MedWorm.com provides a medical RSS filtering service. Over 6000 RSS medical sources are combined and output via different filters. This feed contains the latest items from the 'Psychophysiology' source. Mon, 15 Mar 2010 14:57:51 +0100 http://www.medworm.com/index.php?rid=3356436&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2010.00977.x We examined whether startle abnormalities are present in bipolar disorder (BD) patients and their unaffected siblings. Twenty-one remitted patients with BD, 19 unaffected siblings, and 42 controls were presented with 18 pleasant, 18 unpleasant, and 18 neutral pictures. Acoustic probes (104 dB) were presented during 12 of 18 pictures in each affective category at 300, 3000, and 4500 ms after picture onset, so that there were 4 pictures per valence per probe onset type. Baseline startle was assessed during blank screens and was found reduced in patients and sibling groups. We found startle inhibition with the 300 probes and a linear increase in amplitude with valence with the late probes in controls; these effects were absent in patients and their siblings. Low startle and blunted startle re... Psychophysiology journals http://www.medworm.com/rss/comments.php?id=3356436 Fri, 12 Mar 2010 00:00:00 +0100 3356436 http://www.medworm.com/index.php?rid=3352152&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2010.00999.x Approach motivation has been reliably associated with relative left prefrontal brain activity as measured with electroencephalography (EEG). Motivation researchers have increasingly used the line bisection task, a behavioral measure of relative cerebral asymmetry, as a neural index of approach motivation-related processes. Despite its wide adoption, however, the line bisection task has not been confirmed as a valid measure of the precise pattern of activity linked to approach motivation. In two studies, we demonstrate that line bisection bias is specifically related to baseline, approach-related, prefrontal EEG alpha asymmetry (Study 1) and is heightened by the same situational factors that heighten the same approach-related prefrontal EEG alpha asymmetry (Study 2). Results support the lin... Psychophysiology journals http://www.medworm.com/rss/comments.php?id=3352152 Thu, 11 Mar 2010 00:00:00 +0100 3352152 http://www.medworm.com/index.php?rid=3352157&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2010.01000.x Prepulse inhibition (PPI) of the acoustic startle reflex (ASR) is the most common psychophysiological index of sensorimotor gating. Several studies have investigated the relationship of PPI of ASR to schizotypy in Caucasians. However, little has been reported on this relationship in Asians. We investigated a possible relationship between PPI of ASR and schizotypy in 79 healthy Japanese subjects. Schizotypy was assessed by the Schizotypal personality Questionnaire (SPQ). PPI was evaluated at signal-to-noise ratios (SnRs: difference between background noise intensity and prepulse intensity) of +12, +16, and +20 dB. The total SPQ score, cognitive/perceptual score, and interpersonal score correlated negatively with PPI at SnR of +16 and +20 dB. We conclude that PPI is associated with the trait... Psychophysiology journals http://www.medworm.com/rss/comments.php?id=3352157 Wed, 10 Mar 2010 00:00:00 +0100 3352157 http://www.medworm.com/index.php?rid=3352156&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2010.01001.x ADHD is characterized by inattention, hyperactivity, and disinhibition, including the inability to screen out distracting stimuli. Prepulse inhibition (PPI) of startle indexes a related gating process and is enhanced during attended compared to ignored stimuli. We predicted that PPI during attended stimuli would be enhanced by the stimulant methylphenidate (MPH) and that this effect would be moderated by baseline PPI. Children with ADHD (n=36) completed a baseline day and a randomized, double-blind medication trial (placebo vs. sustained release MPH). Bilateral startle eyeblink EMG was measured during a tone discrimination task. MPH enhanced PPI during attended, but not during ignored stimuli. Extending findings that pretreatment functioning moderates stimulant effects on PPI, this effect ... Psychophysiology journals http://www.medworm.com/rss/comments.php?id=3352156 Wed, 10 Mar 2010 00:00:00 +0100 3352156 http://www.medworm.com/index.php?rid=3352155&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2010.01002.x This experiment explored whether a late positive potential (LPP) of the event-related brain potential is useful for examining attitudes that people attempt to conceal. Participants identified a set of liked, neutral, and disliked people and viewed sequences consisting of either names or pictures of these people. Disliked people appeared rarely among liked people, and participants either: (1) always accurately reported their negative attitudes toward the people; (2) misreported negative attitudes as positive when they saw a picture of a disliked person; or (3) misreported negative attitudes as positive when they saw a name of a disliked person. Rare negative stimuli evoked a larger-amplitude LPP than frequent positive stimuli. Misreporting attitudes significantly reduced the amplitude diffe... Psychophysiology journals http://www.medworm.com/rss/comments.php?id=3352155 Wed, 10 Mar 2010 00:00:00 +0100 3352155 http://www.medworm.com/index.php?rid=3352154&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2010.01003.x This article proposes an efficient method for the objective and continuous measurement of piloerection. It is based on an optical recording device combined with a discrete Fourier transform analysis quantifying the frequency power related to visible piloerection. The validity of the method was demonstrated in a proof-of-principle experiment involving a person with the exceptional ability to control the erection of his hair. The method reliably mapped all occurrences of visible piloerection and provided insight into the temporal dynamics of the underlying physiological process. It thus proved suitable for future experimental investigation of human piloerection. (Source: Psychophysiology) Psychophysiology journals http://www.medworm.com/rss/comments.php?id=3352154 Wed, 10 Mar 2010 00:00:00 +0100 3352154 http://www.medworm.com/index.php?rid=3352153&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2010.00998.x Target selection can be based on spatial or dimensional/featural mechanisms operating in a location-independent manner. We investigated whether dimension-based attention affects processing in early visual stages. Subjects searched for a singleton target among an 8-item array, with the search display preceded by an identical cue array with a dimensionally non-predictive, but spatially predictive singleton. Reaction times (RTs) were increased for changes in the target-defining dimension but not for featural changes within a dimension. This RT effect was mirrored by modulations of the P1 and anterior transition N2 (tN2). Current density reconstructions revealed increased activity in dorsal occipital cortex and decreased activity in left frontopolar cortex owing to repeated dimensional pop-out... Psychophysiology journals http://www.medworm.com/rss/comments.php?id=3352153 Wed, 10 Mar 2010 00:00:00 +0100 3352153 http://www.medworm.com/index.php?rid=3340590&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2010.00988.x Patients with obsessive-compulsive disorder (OCD) show an increased error-related negativity (ERN), yet previous studies have not controlled for medication use, which may be important given evidence linking performance monitoring to neurotransmitter systems targeted by treatment, such as serotonin. In an examination of 19 unmedicated OCD patients, 19 medicated OCD patients, 19 medicated patient controls without OCD, and 21 unmedicated healthy controls, we found greater ERNs in OCD patients than in controls, irrespective of medication use. Severity of generalized anxiety and depression was associated with ERN amplitude in controls but not patients. These data confirm previous findings of an exaggerated error response in OCD, further showing that it cannot be attributed to medication. The ab... Psychophysiology journals http://www.medworm.com/rss/comments.php?id=3340590 Mon, 08 Mar 2010 00:00:00 +0100 3340590 http://www.medworm.com/index.php?rid=3336927&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2010.00975.x (Source: Psychophysiology) Psychophysiology journals http://www.medworm.com/rss/comments.php?id=3336927 Sat, 06 Mar 2010 00:00:00 +0100 3336927 http://www.medworm.com/index.php?rid=3336928&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2009.00972.x Skin conductance (SC) data are usually characterized by a sequence of overlapping phasic skin conductance responses (SCRs) overlying a tonic component. The variability of SCR shapes hereby complicates the proper decomposition of SC data. A method is proposed for full decomposition of SC data into tonic and phasic components. A two-compartment diffusion model was found to adequately describe a standard SCR shape based on the process of sweat diffusion. Nonnegative deconvolution is used to decompose SC data into discrete compact responses and at the same time assess deviations from the standard SCR shape, which could be ascribed to the additional process of pore opening. Based on the result of single non-overlapped SCRs, response parameters can be estimated precisely as shown in a paradigm w... Psychophysiology journals http://www.medworm.com/rss/comments.php?id=3336928 Fri, 05 Mar 2010 00:00:00 +0100 3336928 http://www.medworm.com/index.php?rid=3333260&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2010.00991.x (Source: Psychophysiology) Psychophysiology journals http://www.medworm.com/rss/comments.php?id=3333260 Fri, 05 Mar 2010 00:00:00 +0100 3333260 http://www.medworm.com/index.php?rid=3333268&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2010.00974.x The minimum number of trials necessary to accurately characterize the error-related negativity (ERN) and the error positivity (Pe) across the life span was investigated using samples of preadolescent children, college-age young adults, and older adults. Event-related potentials and task performance were subsequently measured during a modified flanker task. Response-locked averages were created using sequentially increasing errors of commission in blocks of two. Findings indicated that across all age cohorts ERN and Pe were not significantly different relative to the within-participants grand average after six trials. Further, results indicated that the ERN and Pe exhibited excellent internal reliability in preadolescent children and young adults after six trials, but older adults required ... Psychophysiology journals http://www.medworm.com/rss/comments.php?id=3333268 Thu, 04 Mar 2010 00:00:00 +0100 3333268 http://www.medworm.com/index.php?rid=3333267&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2010.00976.x In detecting deception, the Cognitive Load hypothesis states that lying requires more cognitive resources compared to truth telling. Further, increases in cognitive load are predicted to decrease respiratory sinus arrhythmia (RSA). We evaluated the impact of cognitive tasks and the intent to deceive on RSA in 40 male, native Arabic-speaking participants quasi-randomized into truthful (n=14) or deceptive (n=26) groups. Participants donned an ambulatory physiologic recording device and completed cognitive testing after receiving translated instructions about their role in an impending mock crime. The results show that a decrease in RSA recorded during the cognitive testing was greater in individuals who were about to commit a deceptive act. (Source: Psychophysiology) Psychophysiology journals http://www.medworm.com/rss/comments.php?id=3333267 Thu, 04 Mar 2010 00:00:00 +0100 3333267 http://www.medworm.com/index.php?rid=3333266&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2010.00978.x Chronic fatigue syndrome (CFS) patients often report symptom flare (SF) for >24 h after moderate exercise (post-ex). We hypothesized that SF is linked to increases in circulating cytokines and CD40 Ligand (CD40L). In 19 CFS patients and 17 controls, mental and physical fatigue and pain symptom ratings were obtained together with serum for 11 cytokines and CD40L before and at 0.5, 8, 24, and 48 h post-ex. Before exercise, CFS had lower CD40L (p (Source: Psychophysiology) Psychophysiology journals http://www.medworm.com/rss/comments.php?id=3333266 Thu, 04 Mar 2010 00:00:00 +0100 3333266 http://www.medworm.com/index.php?rid=3333265&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2010.00979.x Reaction times (RT) to targets are faster in repeated displays relative to novel ones when the spatial arrangement of the distracting items predicts the target location (contextual cueing). It is assumed that visual[ndash]spatial attention is guided more efficiently to the target resulting in reduced RTs. In the present experiment, contextual cueing even occurred when the target location was previously peripherally cued. Electrophysiologically, repeated displays elicited an enhanced N2pc component in both conditions and resulted in an earlier onset of the stimulus-locked lateralized readiness potential (s-LRP) in the cued condition and in an enhanced P3 in the uncued condition relative to novel displays. These results indicate that attentional guidance is less important than previously ass... Psychophysiology journals http://www.medworm.com/rss/comments.php?id=3333265 Thu, 04 Mar 2010 00:00:00 +0100 3333265 http://www.medworm.com/index.php?rid=3333264&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2010.00986.x In attended novelty oddball tasks, rare nontarget stimuli can elicit two late positive ERP components: P3a and P300. In passive oddball tasks, P300 is not elicited by these stimuli. In passive tasks, however, P3a is accompanied by another positive component, termed eP3a, which may have evaded detection in attended oddball tasks because of its spatiotemporal overlap with P300. To address this, temporal-spatial principal components analysis was used to quantify ERPs recorded in attended three-tone and novelty oddball tasks. As expected, novel stimuli elicited both P3a and P300. The analysis also identified a third component, evident in novelty ERPs as an inflection on the leading edge of P3a. This component has the same antecedent conditions as P3a, but is earlier and more centrally distribu... Psychophysiology journals http://www.medworm.com/rss/comments.php?id=3333264 Thu, 04 Mar 2010 00:00:00 +0100 3333264 http://www.medworm.com/index.php?rid=3333263&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2010.00987.x In this study, the cortical dynamics of the visual change detection process were investigated using an oddball paradigm similar to that used in auditory mismatch negativity studies. When subjects watched a silent movie, color stimuli were presented using 280 dual color LEDs arranged along the frame of the video screen. Task-irrelevant red and blue color stimuli were presented randomly at a probability of 10% and 90%, respectively, in one session and vice versa for the other one, and we traced brain responses using magnetoencephalography. Results show that activation in the middle occipital gyrus (MOG) was significantly enhanced for the infrequent stimulus, while early activities in Brodmann's area 17/18 were comparable for the frequent and infrequent stimuli. These results suggest that aut... Psychophysiology journals http://www.medworm.com/rss/comments.php?id=3333263 Thu, 04 Mar 2010 00:00:00 +0100 3333263 http://www.medworm.com/index.php?rid=3333262&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2010.00989.x Event-related potentials (ERPs) were obtained from an identity priming task, where a green target had to be selected against a superimposed red distractor. Several priming conditions were realized in a mix of control (CO), negative priming (NP), and positive priming (PP) trials. PP and NP effects in reaction times (RTs) were significant. ERP results conceptually replicate earlier findings of left-posterior P300 reduction in PP and NP trials compared to CO. This ERP effect may reflect the detection of prime-probe similarity corresponding to the concept of a retrieval cue. A novel finding concerned amplitude increase of the frontal late positive complex (LPC) in the order NP, CO, and PP. NP therefore seemed to induce brain activity related to cognitive control and/or memory processes, with r... Psychophysiology journals http://www.medworm.com/rss/comments.php?id=3333262 Thu, 04 Mar 2010 00:00:00 +0100 3333262 http://www.medworm.com/index.php?rid=3333261&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2010.00990.x An experimental model for investigating the processes involved in reacting to unpredictable events is the oddball paradigm. We investigated how the commonality or independence of response options (i.e., many-to-one vs. one-to-one stimulus-response mappings) influences processing in an auditory oddball paradigm. Participants performed a discrimination task with two one-to-one and one two-to-one mappings. The pattern of conflict- and oddball-related N2 event-related potentials suggest that information that would allow correct responding is represented at the latency of the N2. Integration of this information takes place only by the latency of P3b, and longer reaction times to rare stimuli are probably due to processes preventing the utilization of this information. We also suggest that, in t... Psychophysiology journals http://www.medworm.com/rss/comments.php?id=3333261 Thu, 04 Mar 2010 00:00:00 +0100 3333261 http://www.medworm.com/index.php?rid=3328966&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2010.00967.x Human brain theta rhythm has been related to the operation of a generic mechanism involved in error detection processes of different types (e.g., detecting incorrect motor responses or incorrect arithmetic equations). This theta activity seems to be sensitive to error salience or magnitude, that is, stronger theta activity is found with larger or more deviant errors (e.g., 1+2=8) than with smaller or less deviant ones (e.g., 1+2=4). A time-frequency decomposition analysis indicated that theta activity is modulated by the magnitude of erroneous information in a nonlinear fashion, which can be characterized using Weber[ndash]Fechner's law of logarithmic function and Stevens' law of power function. The present study suggests that the generic mechanisms for error detection and evaluation may s... Psychophysiology journals http://www.medworm.com/rss/comments.php?id=3328966 Thu, 04 Mar 2010 00:00:00 +0100 3328966 http://www.medworm.com/index.php?rid=3300017&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2010.00985.x The aim of this study was to examine the effects of instructions and expertise upon neuronal changes during observation of sequential finger movements. Professional pianists and musically naïve subjects observed these movements with the aim of either replicating or recognizing them at a later stage. A non-linear measure of functional coupling was used to investigate EEG activity. In the 10[ndash]13 Hz frequency band and in musically naïve subjects, functional coupling during observation for replica was greater within central and neighboring areas than during observation for recognition. An opposite pattern was found in the 4[ndash]8 Hz frequency band. In the 10[ndash]13 Hz band and in areas including the parietal cortex, functional coupling in musically naïve subjects was greater compar... Psychophysiology journals http://www.medworm.com/rss/comments.php?id=3300017 Wed, 24 Feb 2010 00:00:00 +0100 3300017 http://www.medworm.com/index.php?rid=3296343&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2010.00983.x ERPs were recorded as older adults decided if a target word was related to a lateralized ambiguous or unambiguous prime; prime-target pairs were preceded by a related or unrelated context word. In an unrelated context, N400 facilitation effects differed from those seen in young adults, with older adults showing priming for the dominant meaning (e.g., BOOM-BANK-DEPOSIT) on right visual field/left hemisphere (RVF/LH) trials and priming for the subordinate meaning (e.g., BOOM-BANK-RIVER) on LVF/RH trials. Higher-functioning older adults, especially those with better inhibition, were more likely to show bilateral activation of the dominant meaning and unilateral activation of the subordinate meaning, suggesting a retention of young-like activation. In a biasing context (e.g., RIVER-BANK-DEPOSI... Psychophysiology journals http://www.medworm.com/rss/comments.php?id=3296343 Tue, 23 Feb 2010 00:00:00 +0100 3296343 http://www.medworm.com/index.php?rid=3296345&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2010.00964.x In the present study we tested the applicability of a paired-stimulus paradigm for the investigation of near-threshold (NT) stimulus processing in the somatosensory system using magnetoencephalography. Cortical processing of the NT stimuli was studied indirectly by investigating the impact of NT stimuli on the source activity of succeeding suprathreshold test stimuli. We hypothesized that cortical responses evoked by test stimuli are reduced due to the preactivation of the same finger representation by the preceding NT stimulus. We observed attenuation of the magnetic responses in the secondary somatosensory (SII) cortex, with stronger decreases for perceived than for missed NT stimuli. Our data suggest that processing in the primary somatosensory cortex including recovery lasts for (Sourc... Psychophysiology journals http://www.medworm.com/rss/comments.php?id=3296345 Mon, 22 Feb 2010 00:00:00 +0100 3296345 http://www.medworm.com/index.php?rid=3296344&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2009.00970.x We describe a new approach, in which independent components with high trial-by-trial variance are first removed. Next, each deviant response has the preceding standard response subtracted, giving a set of single trial difference waves. We illustrate this approach in analysis of MMN to brief tones in 17 adults. The best criterion for MMN combined t-test with an index of inter-trial coherence, giving significant MMN in 14 (82%) of individuals. Single-trial methods can indicate which people show MMN. However, in some clinically normal individuals there was no MMN, despite good behavioral discrimination of stimuli. (Source: Psychophysiology) Psychophysiology journals http://www.medworm.com/rss/comments.php?id=3296344 Mon, 22 Feb 2010 00:00:00 +0100 3296344 http://www.medworm.com/index.php?rid=3264685&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2010.00984.x This article examines the impact of task control on perceived control and cardiovascular processes. Fifty-eight undergraduates performed a computer task where the functionality of the computer mouse was used to manipulate task control. Results are consistent with the proposition that actual control triggers an initial physiological response which can be modified temporally later by perceived control and that male participants react psychologically faster to changes in task control than female participants. (Source: Psychophysiology) Psychophysiology journals http://www.medworm.com/rss/comments.php?id=3264685 Fri, 12 Feb 2010 00:00:00 +0100 3264685 http://www.medworm.com/index.php?rid=3264687&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2010.00980.x Anxiety disorders have been linked to a hyperactivated cortico-amygdalar circuitry, but the amygdala's role in the pathophysiology of obsessive-compulsive disorder (OCD) remains unclear. This fMRI study examined the cortico-limbic correlates of individually tailored symptom provocation in 14 unmedicated OCD patients and 14 controls. In addition to OCD-relevant pictures, aversive and neutral control stimuli were included. Patients showed increased fronto-striatal activation to OCD-relevant stimuli contrasted with both control categories. Briefly presented symptom-related triggers elicited stronger amygdala engagement in patients than in controls. This effect, however, did also occur to aversive stimuli and was not symptom specific. Augmented amygdala involvement in patients reflects general... Psychophysiology journals http://www.medworm.com/rss/comments.php?id=3264687 Thu, 11 Feb 2010 00:00:00 +0100 3264687 http://www.medworm.com/index.php?rid=3264686&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2010.00982.x Recent research suggests that the allocation of attentional resources to emotional content during word processing might be sensitive to task requirements. This question was investigated in two tasks with similar instructions. The stimuli were positive, negative, and neutral nouns. Participants had to identify meaningful words embedded in a stream of non-recognizable stimuli (task 1) or pseudowords (task 2). Task 1 could be successfully performed on the basis of the perceptual features whereas a lexico-semantic analysis was required in task 2. Effects were found only in task 2. Positive nouns were identified faster, with fewer errors and elicited larger amplitude in an early negativity. Also, the amplitude of a late positivity was larger for both positive and negative nouns than for neutral... Psychophysiology journals http://www.medworm.com/rss/comments.php?id=3264686 Thu, 11 Feb 2010 00:00:00 +0100 3264686 http://www.medworm.com/index.php?rid=3252475&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2010.00981.x Neuroimaging studies have provided evidence that a bilateral frontal-parietal network is involved in voluntary attentional control. However, because those studies used instructive cue stimuli, some of the activity may have been due to interactions between cue processing and voluntary orienting. Here, we show that self-initiated voluntary orienting, in the absence of any cue stimulus, evokes activity in this frontal-parietal network. In contrast to the typical symmetric activity observed with cued attentional shifts, self-initiated shifts showed a hemispheric asymmetry consistent with studies of unilateral neglect patients. Specifically, the right hemisphere was equally involved in orienting to either visual field, whereas the left hemisphere was biased toward the contralateral field. Our d... Psychophysiology journals http://www.medworm.com/rss/comments.php?id=3252475 Tue, 09 Feb 2010 00:00:00 +0100 3252475 http://www.medworm.com/index.php?rid=3233594&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2010.00966.x The present study examined the interaction of anticipatory anxiety and selective emotion processing. Toward this end, a rapid stream of pleasant, neutral, and unpleasant pictures was presented in alternating blocks of threat-of-shock or safety, which were signaled by colored picture frames. The main finding is that pleasant pictures elicited a sustained negative difference potential over occipital regions during threat as compared to safety periods. In contrast, unpleasant and neutral picture processing did not vary as a function of threat-of-shock. Furthermore, in both the safety and threat-of-shock conditions, emotional pictures elicited an enlarged early posterior negativity and late positive potential. These data show that the activation of the fear/anxiety network exerts valence-speci... Psychophysiology journals http://www.medworm.com/rss/comments.php?id=3233594 Wed, 03 Feb 2010 00:00:00 +0100 3233594 http://www.medworm.com/index.php?rid=3233597&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2010.00962.x Four experiments are reported that investigated visual event integration by using a variant of the missing element paradigm. Good performance on this task depends on whether two brief successive stimulus displays are perceived as (or integrated into) one single event. We replicated the classic finding of greater accuracy with shorter duration of the first stimulus and ruled out an attention-related account thereof. In a subsequent electrophysiological experiment we found that successful event integration increased the amplitude of the N1, N2, and late P3 components of the event-related potential and decreased early P3 amplitude. No effect on the P1 was observed. The results provided evidence for an early onset of event integration in time and demonstrated the existence of electrophysiologi... Psychophysiology journals http://www.medworm.com/rss/comments.php?id=3233597 Tue, 02 Feb 2010 00:00:00 +0100 3233597 http://www.medworm.com/index.php?rid=3233596&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2010.00963.x Three largely independent lines of research have investigated experimental manipulations that influence the amplitude of the N2 component of the event-related brain potential (ERP), one linking heightened N2 amplitude to response conflict, another showing that N2 is sensitive to stimulus infrequency, and the third showing larger N2 amplitude during categorization of racial ingroup relative to racial outgroup targets. The purpose of this research was to investigate potential interactions between these three features on the amplitude of the N2. ERPs were recorded while participants completed a modified flanker task using pictures of ingroup and outgroup faces. Results showed a 3-way interaction, indicating that the N2 was largest for ingroup targets on high-conflict trials but only when such... Psychophysiology journals http://www.medworm.com/rss/comments.php?id=3233596 Tue, 02 Feb 2010 00:00:00 +0100 3233596 http://www.medworm.com/index.php?rid=3233595&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2010.00965.x Using a spatial cueing paradigm with emotional and neutral facial expressions as cues, we examined early and late patterns of information processing in cognitive avoidant coping (CAV). Participants were required to detect a target that appeared either in the same location as the cue (valid) or in a different location (invalid). Cue[ndash]target onset asynchrony (CTOA) was manipulated to be short (250 ms) or long (750 ms). CAV was associated with early facilitation and faster disengagement from angry faces. No effects were found for happy or neutral faces. After completing the spatial cueing task, participants prepared and delivered a public speech and heart rate variability (HRV) was recorded. Disengagement from angry faces was related to a decrease in HRV in response to this task. Togethe... Psychophysiology journals http://www.medworm.com/rss/comments.php?id=3233595 Tue, 02 Feb 2010 00:00:00 +0100 3233595 http://www.medworm.com/index.php?rid=3222016&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2009.00973.x According to the dual-mechanisms of cognitive control framework (DMC), older adults rely predominantly on reactive as opposed to proactive control. As a result, we expected elevated response conflict for older relative to younger adults with increasing task difficulty. Response-locked ERP activity was examined separately for fast and slow responses (representing proactive and reactive control, respectively) at low, medium, and high levels of difficulty. Older adults recruited reactive control more often than the young, as reflected by increased behavioral costs and enhanced pre-response negativity (PRN). No age differences in conflict detection (medial frontal negativity, MFN) were evident at low levels of difficulty, but response conflict increased along with difficulty for older adults. ... Psychophysiology journals http://www.medworm.com/rss/comments.php?id=3222016 Sat, 30 Jan 2010 00:00:00 +0100 3222016 http://www.medworm.com/index.php?rid=3222017&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2009.00969.x Associative processing in the cerebral hemispheres was examined using ERPs and visual half-field (VF) methods. Associative strength was manipulated using asymmetrically associated pairs: viewed in one order (forward), there was a strong prime-to-target association, but in the backward order, predictability was weak. N400 priming was greater for forward than backward pairs in both VFs and not different across VF, suggesting similar semantic representations and automatic meaning activation in the two hemispheres. However, a frontal P2 enhancement for forward pairs restricted to the LH suggests that it uses context to predict likely upcoming words. Also, greater late positive complex priming for backward pairs in the LH than the RH reveals a LH advantage for strategically reshaping meaning ac... Psychophysiology journals http://www.medworm.com/rss/comments.php?id=3222017 Fri, 29 Jan 2010 00:00:00 +0100 3222017 http://www.medworm.com/index.php?rid=3199369&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2009.00971.x The interhemispheric asymmetries that originate from connectivity-related structuring of the cortex are compromised in schizophrenia (SZ). Under the assumption that such abnormalities affect functional connectivity, we analyzed its correlate[mdash]EEG synchronization[mdash]in SZ patients and matched controls. We applied multivariate synchronization measures based on Laplacian EEG and tuned to various spatial scales. Compared to the controls who had rightward asymmetry at a local level (EEG power), rightward anterior and leftward posterior asymmetries at an intraregional level (1st and 2nd order S-estimator), and rightward global asymmetry (hemispheric S-estimator), SZ patients showed generally attenuated asymmetry, the effect being strongest for intraregional synchronization in the alpha a... Psychophysiology journals http://www.medworm.com/rss/comments.php?id=3199369 Sat, 23 Jan 2010 00:00:00 +0100 3199369 http://www.medworm.com/index.php?rid=3199370&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2009.00968.x Oxytocin (OT) is a peptide increasingly studied in relation to human social interactions, affiliation, and clinical disorders. Studies are constrained by use of invasive blood draws and would benefit from a reliable salivary OT assay. Our goals were to examine feasibility of salivary OT measurement, compare salivary to plasma OT responses in 12 breast- and 8 formula-feeding mothers, and assess the degree of correlation between plasma and salivary OT. Using a commercial EIA kit, we measured OT in 5 saliva and 7 plasma samples in a protocol designed to elicit changes in OT (Rest, Infant Interaction, Stress, Feeding). Breast-feeders had higher OT levels than formula-feeders across all conditions in plasma (+36%) and saliva (+23%). OT levels and ranges were similar in saliva and plasma, with s... Psychophysiology journals http://www.medworm.com/rss/comments.php?id=3199370 Fri, 22 Jan 2010 00:00:00 +0100 3199370 http://www.medworm.com/index.php?rid=3187285&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2009.00960.x Words with many orthographic neighbors elicit a larger N400 than words with few orthographic neighbors. This has been interpreted as stronger overall semantic activation due to orthographic neighbors activating their semantic representations. To investigate this claim, we manipulated the number of associates of words (NoA), a variable directly affecting overall semantic activation, and compared this to the ERP effect of the number of orthographic neighbors (N) in a lexical decision task. Words with high NoA and with high N produced a very similar increase of the N400. In addition, a higher N increased the amplitude of the Late Positive Complex. The common N400 effect suggests that N affects semantic activation, like NoA does. The late positive effect specific to N could occur because words... Psychophysiology journals http://www.medworm.com/rss/comments.php?id=3187285 Wed, 20 Jan 2010 00:00:00 +0100 3187285 http://www.medworm.com/index.php?rid=3187286&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2009.00954.x The study investigated event-related EEG potentials during concurrent performance of interlimb coordination and visual oddball tasks by younger and older adults. Coordination task difficulty was equated between age groups by allowing participants to perform the task at self-determined frequencies. The amplitude of the P3b component of the event-related potentials (ERPs) elicited by visual task targets showed a different pattern across midline sites (Fz, Cz, Pz) for younger and older adults. While younger adults showed a parietal maximum, P3b amplitudes in older adults did not differ across midline site, with lower amplitudes at central and parietal sites than younger adults but higher amplitude at the frontal site. Younger adults also had significantly shorter P3b latency than older adults... Psychophysiology journals http://www.medworm.com/rss/comments.php?id=3187286 Tue, 19 Jan 2010 00:00:00 +0100 3187286 http://www.medworm.com/index.php?rid=3169323&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2009.00944.x In conclusion, ERN and FRN, but not P300, may be sensitive to affective distress elicited by expectation violations during social interaction. (Source: Psychophysiology) Psychophysiology journals http://www.medworm.com/rss/comments.php?id=3169323 Thu, 14 Jan 2010 00:00:00 +0100 3169323 http://www.medworm.com/index.php?rid=3161451&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2009.00959.x Stimulus-locked, response-locked, and ERP-locked averaging are effective methods for reducing artifacts in ERP analysis. However, they suffer from a magnifying-glass effect: they increase the resolution of specific ERPs at the cost of blurring other ERPs. Here we propose an extremely simple technique[mdash]binning trials based on response times and then averaging[mdash]which can significantly alleviate the problems of other averaging methods. We have empirically evaluated the technique in an experiment where the task requires detecting a target in the presence of distractors. We have also studied the signal-to-noise ratio and the resolving power of averages with and without binning. Results indicate that the method produces clearer representations of ERPs than either stimulus-locked and re... Psychophysiology journals http://www.medworm.com/rss/comments.php?id=3161451 Tue, 12 Jan 2010 00:00:00 +0100 3161451 http://www.medworm.com/index.php?rid=3161458&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2009.00947.x Two experiments examined the effectiveness of the pupillary response as a measure of cognitive load in younger and older adults. Experiment 1 measured the change in pupil size of younger and older adults while they listened to spoken digit lists that varied in length and retained them briefly for recall. In Experiment 2 changes in relative pupil size were measured while younger and older adults listened to sentences for later recall that varied in syntactic complexity and sentence length. Both age groups' pupil sizes were sensitive to the size of the memory set in Experiment 1 and sentence length in Experiment 2, with the older adults showing a larger effect of the memory load on a normalized measure of pupil size relative to the younger adults. By contrast, only the younger adults showed ... Psychophysiology journals http://www.medworm.com/rss/comments.php?id=3161458 Mon, 11 Jan 2010 00:00:00 +0100 3161458 http://www.medworm.com/index.php?rid=3161457&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2009.00955.x This article reviews event-related potential (ERP) studies investigating the role played by cognitive control and conflict resolution processes in social-cognitive phenomena typically deemed automatic. Neurocognitive responses associated with response activation and conflict often are sensitive to the same stimulus manipulations that produce differential behavioral responses on social-cognitive tasks and that often are attributed to the role of automatic associations. Findings are discussed in the context of an overarching social cognitive neuroscience model in which physiological data are used to constrain social-cognitive theories. (Source: Psychophysiology) Psychophysiology journals http://www.medworm.com/rss/comments.php?id=3161457 Mon, 11 Jan 2010 00:00:00 +0100 3161457 http://www.medworm.com/index.php?rid=3161456&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2009.00957.x Salivary [alpha]-amylase (sAA) increases rapidly in response to psychosocial stress in young adults, but no direct comparisons between different age groups across the life span have been made. Secretion of sAA and cortisol was assessed in children, young adults, and older adults after exposure to the Trier Social Stress Test. Additionally, cardiovascular activity was measured in both adult groups. Older adults showed attenuated sAA, heart rate (HR), and heart rate variability (HRV) responses. Furthermore, we found higher sAA but lower cortisol at baseline as well as lower sAA and cortisol responses in children. Age × sex interactions were observed only for cortisol with higher responses in older male participants. No associations between the parameters were found. These results implicate ... Psychophysiology journals http://www.medworm.com/rss/comments.php?id=3161456 Mon, 11 Jan 2010 00:00:00 +0100 3161456 http://www.medworm.com/index.php?rid=3161455&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2009.00961.x The prevalence of stress disorders differs between men and women. An understanding of how men and women vary in acute stress responses may help to understand these sex differences. We compared responses to the TSST and a control task in healthy men (N=28) and women tested in two phases (Follicular N=29, Luteal N=23) of the menstrual cycle. Men exhibited greater cortisol responses to stress than women in either phase. Luteal women exhibited the greatest subjective and allopregnanolone responses to stress, whereas follicular women exhibited blunted noradrenaline responses. Partial correlations controlling for group differences revealed that individuals who were most sensitive to the subjective effects of stress exhibited the largest salivary cortisol, noradrenaline, and allopregnanolone resp... Psychophysiology journals http://www.medworm.com/rss/comments.php?id=3161455 Mon, 11 Jan 2010 00:00:00 +0100 3161455 http://www.medworm.com/index.php?rid=3161454&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2009.00946.x Before starting a smoking cessation treatment, 51 smokers took part in a study aimed at investigating brain mechanisms associated with attention allocation. Event-related potentials to acoustic startle probes were recorded from 129 sensors during the presentation of neutral, pleasant, unpleasant, and cigarette-related pictures. Results indicated that the amplitude of the startle probe P3 component was reduced for pleasant, unpleasant, and cigarette-related conditions relative to neutral. Surface Laplacian estimates showed that sources of electrocortical activity under frontal and parietal sensors contributed to the modulation of this effect. For smokers, cigarette-related stimuli, like intrinsically motivating ones, capture attentional resources and therefore reduce the ability to process ... Psychophysiology journals http://www.medworm.com/rss/comments.php?id=3161454 Mon, 11 Jan 2010 00:00:00 +0100 3161454 http://www.medworm.com/index.php?rid=3161453&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2009.00948.x To carry out tasks with the highest possible efficiency we have developed executive mechanisms that monitor task performance and optimize cognitive processing. It has been hypothesized that these executive mechanisms operate even without conscious awareness to maximize their sensitivity to task-relevant outcomes. To test this hypothesis the present study examined the error-related negativity (ERN), an electrophysiological index of the performance-monitoring neural circuitry, during masked visual search. The findings show that representations of target objects that are processed perceptually, but not to the level of awareness, fail to elicit an ERN despite the ability of these targets to elicit a shift of attention. These findings indicate that the performance-monitoring mechanism indexed b... Psychophysiology journals http://www.medworm.com/rss/comments.php?id=3161453 Mon, 11 Jan 2010 00:00:00 +0100 3161453 http://www.medworm.com/index.php?rid=3161452&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2009.00958.x Although numerous EEG studies have shown that depression is associated with abnormal functional asymmetries in frontal cortex, fMRI and PET studies have largely failed to identify specific brain areas showing this effect. The present study tested the hypothesis that emotion processes are related to asymmetric patterns of fMRI activity, particularly within dorsolateral prefrontal cortex (DLPFC). Eleven depressed and 18 control participants identified the color in which pleasant, neutral, and unpleasant words were printed. Both groups showed a leftward lateralization for pleasant words in DLPFC. In a neighboring DLPFC area, the depression group showed more right-lateralized activation than controls, replicating EEG findings. These data confirm that emotional stimulus processing and trait dep... Psychophysiology journals http://www.medworm.com/rss/comments.php?id=3161452 Mon, 11 Jan 2010 00:00:00 +0100 3161452 http://www.medworm.com/index.php?rid=3151010&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2009.00956.x We examined the impact of viewing pleasant, neutral, and unpleasant affective pictures on the respiratory-related evoked potential (RREP) elicited by a short inspiratory occlusion in healthy volunteers. Reduced P3 amplitude of the RREP was found for respiratory probes presented when viewing pleasant or unpleasant series, when compared to those presented during the neutral series. Earlier RREP components, such as Nf, P1, N1, and P2, showed no modulation by emotion. The results suggest that emotion impacts the perception of respiratory sensations by reducing the attentional resources available for processing afferent respiratory sensory signals. (Source: Psychophysiology) Psychophysiology journals http://www.medworm.com/rss/comments.php?id=3151010 Fri, 08 Jan 2010 00:00:00 +0100 3151010 http://www.medworm.com/index.php?rid=3151011&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2009.00943.x The association between defensiveness and physiological responses to stress were evaluated in 81 healthy working men and 118 women, aged 20 to 64 years (M=41; SD=11.45). Participants underwent laboratory testing during which they were exposed to interpersonal stressors. Heart rate (HR), heart rate variability (HRV), blood pressure (BP), and salivary cortisol were measured. Defensiveness was evaluated using the Marlowe-Crowne Social Desirability Scale. In women, higher defensiveness was associated with greater BP and HR reactivity to stress (p (Source: Psychophysiology) Psychophysiology journals http://www.medworm.com/rss/comments.php?id=3151011 Thu, 07 Jan 2010 00:00:00 +0100 3151011 http://www.medworm.com/index.php?rid=3113051&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2009.00953.x In this study we assessed blood pressure (BP), heart rate (HR), stroke volume (SV), cardiac output (CO), and total peripheral resistance (TPR) in response to 13 picture series in 37 participants in order to investigate their hemodynamic response associated with activation of the appetitive and defensive motivational systems underlying emotional experience. BP and SV, but not TPR, increased with increasing self-rated arousal, whereas HR decelerated more in response to negative than positive and neutral pictures. These findings suggest that modulation of the cardiovascular response to pictures is primarily myocardial. The observed response pattern is consistent with a configuration of cardiac sympathetic[ndash]parasympathetic coactivation. The relationships between self-rated arousal, BP, an... Psychophysiology journals http://www.medworm.com/rss/comments.php?id=3113051 Wed, 23 Dec 2009 00:00:00 +0100 3113051 http://www.medworm.com/index.php?rid=3113056&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2009.00945.x This study examined the relationship between cardiovascular markers of challenge/threat motivation and university course performance. Before the first course exam, participants gave speeches on academics-relevant topics while their cardiovascular responses were recorded. Participants who exhibited cardiovascular markers of relative challenge (lower total peripheral resistance and higher cardiac output) while discussing academic interests performed better in the subsequent course than those who exhibited cardiovascular markers of relative threat. This relationship remained significant after controlling for two other important predictors of performance (college entrance exam score and academic self-efficacy). These results have implications for the challenge/threat model and for understandin... Psychophysiology journals http://www.medworm.com/rss/comments.php?id=3113056 Tue, 22 Dec 2009 00:00:00 +0100 3113056 http://www.medworm.com/index.php?rid=3113055&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2009.00949.x Recent research suggests a relationship between empathy and error processing. Error processing is an evaluative control function that can be measured using post-error response time slowing and the error-related negativity (ERN) and post-error positivity (Pe) components of the event-related potential (ERP). Thirty healthy participants completed two measures of empathy, the Interpersonal Reactivity Index (IRI) and the Empathy Quotient (EQ), and a modified Stroop task. Post-error slowing was associated with increased empathic personal distress on the IRI. ERN amplitude was related to overall empathy score on the EQ and the fantasy subscale of the IRI. The Pe and measures of empathy were not related. Results remained consistent when negative affect was controlled via partial correlation, with ... Psychophysiology journals http://www.medworm.com/rss/comments.php?id=3113055 Tue, 22 Dec 2009 00:00:00 +0100 3113055 http://www.medworm.com/index.php?rid=3113054&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2009.00950.x We measured ERPs of professional boxers in a Go/No-Go task, comparing them to fencers and non-athletes. Results showed that fencing improved attention and motor response control, but boxing did not. More strikingly, in boxers, as in brain trauma patients, the P3 component was delayed and reduced. The P3 delay of boxers was correlated with the amount of performed sport exercise. Furthermore, in terms of behavior, boxers showed increased intra-individual variability and switch cost. Results were consistent with the hypothesis of specific impairment at the level of response inhibition processing. We suggest that this impairment is derived from the cumulative effect of blows to the head. The changes found in boxers suggest that ERPs and reaction times may be a tool for early detection of speci... Psychophysiology journals http://www.medworm.com/rss/comments.php?id=3113054 Tue, 22 Dec 2009 00:00:00 +0100 3113054 http://www.medworm.com/index.php?rid=3113053&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2009.00951.x A non-clinical group high on heterogeneous medically unexplained symptoms (MUS; n=97) was compared with healthy controls (n=66) on the within-subject relationships between physiological measures using multilevel path analysis. Momentary experienced somatic complaints, mood (tension and depression), cardiac autonomic activity (inter-beat intervals, pre-ejection period (PEP), and respiratory sinus arrhythmia (RSA)) and respiration (rate and partial pressure of CO2 at the end of a normal expiration) were monitored for 24 h using electronic diary and ambulatory devices. Relationships between measures were controlled for diurnal variation and individual means. Only subtle group differences were found in the diurnal rhythm and in the within-subject relationships between physiological measures. F... Psychophysiology journals http://www.medworm.com/rss/comments.php?id=3113053 Tue, 22 Dec 2009 00:00:00 +0100 3113053 http://www.medworm.com/index.php?rid=3113052&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2009.00952.x Blindfolded participants performed one-dimensional movements towards a mechanical stop and back to the start. After a varying delay, they had to reproduce the encoded target position by a second mechanically unrestricted movement. Average event-related potentials accompanying the "encoding" and the "reproduction" movements revealed a biphasic waveshape over primary sensorimotor areas. The first negative deflection was the gradually increasing motor potential (MP) that precedes movement onset. This was followed by a second negative component (N4) starting about 100 ms after movement onset. Its amplitude and latency increased with increasing movement distance and reached its maximum in unrestricted movements (i.e., during reproduction) shortly before the deceleration peak. These results show... Psychophysiology journals http://www.medworm.com/rss/comments.php?id=3113052 Tue, 22 Dec 2009 00:00:00 +0100 3113052 http://www.medworm.com/index.php?rid=3098442&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2009.00941.x Vaginal pulse amplitude (VPA) has been the most commonly analyzed signal of the vaginal photoplethysmograph. Frequent, large, and variable-morphology artifacts typically have crowded this signal. These artifacts usually were corrected by hand, which may have introduced large differences in outcomes across laboratories. VPA signals were collected from 22 women who viewed a neutral film and a sexual film. An automated, wavelet-based, denoising algorithm was compared against the uncorrected signal and the signal corrected in the typical manner (by hand). The automated wavelet denoising resulted in the same pattern of results as the hand-corrected signal. The wavelet procedure automated artifact reduction in the VPA, and this mathematical instantiation permits the comparison of competing metho... Psychophysiology journals http://www.medworm.com/rss/comments.php?id=3098442 Fri, 18 Dec 2009 00:00:00 +0100 3098442 http://www.medworm.com/index.php?rid=3094363&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2009.00942.x The error-related negativity (ERN) and feedback-related negativity (FRN) have been used as electrophysiological indices of performance monitoring produced in response to internally generated (errors) and externally generated (feedback) activations of the anterior cingulate cortex (ACC). No studies to date have systematically examined the measurement reliability of these components. In this article, we present the retest reliability of the ERN and FRN during response tasks designed to elicit errors or feedback responses on two occasions. Data from four experiments are presented in which participants performed tasks over various periods of time. Results indicate good retest reliability of the ERN and FRN amplitudes and source generation of these components. The present article provides impor... Psychophysiology journals http://www.medworm.com/rss/comments.php?id=3094363 Thu, 17 Dec 2009 00:00:00 +0100 3094363 http://www.medworm.com/index.php?rid=3094367&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2009.00937.x To examine how people deal with perceivable consequences of their voluntary actions, we recorded event-related potentials (ERPs) during a self-paced, two-choice random generation task. Sixteen participants were asked to press one of two buttons randomly at a regular but self-selected interval of once per 1[ndash]2 s. Each button press produced either a 1000-Hz or 2000-Hz tone, but participants were told that the tones were irrelevant to the task. The button[ndash]tone combinations were initially fixed, but in subsequent blocks, a button press infrequently produced the tone associated with the opposite button (p=.15). This cognitively mismatched tone elicited N2, P3, and late positive potential (or positive slow wave) of the ERP and delayed the timing of the next button press. These results... Psychophysiology journals http://www.medworm.com/rss/comments.php?id=3094367 Wed, 16 Dec 2009 00:00:00 +0100 3094367 http://www.medworm.com/index.php?rid=3094366&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2009.00938.x Anxiety is supposed to enhance the processing of threatening information. Here, we investigated the cortical processing of angry faces during anticipated public speaking. To elicit anxiety, a group of participants was told that they would have to perform a public speech. As a control condition, another group was told that they would have to write a short essay. During anticipation of these tasks, participants saw facial expressions (angry, happy, and neutral) while electroencephalogram was recorded. Event-related potential analysis revealed larger N170 amplitudes for angry compared to happy and neutral faces in the anxiety group. The early posterior negativity as an index of motivated attention was also enhanced for angry compared to happy and neutral faces in participants anticipating pub... Psychophysiology journals http://www.medworm.com/rss/comments.php?id=3094366 Wed, 16 Dec 2009 00:00:00 +0100 3094366 http://www.medworm.com/index.php?rid=3094365&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2009.00939.x Reduced perception of somatosensory stimulation in patients with essential hypertension may be due to deficits in the ascending somatosensory pathway. Function in the ascending somatosensory pathway was assessed by measuring N9, N13, and N20 somatosensory-evoked potentials in 14 unmedicated essential hypertensives and 22 normotensives. N9 amplitudes were smaller and N13 amplitudes marginally smaller in hypertensives than normotensives. N9 amplitudes were inversely associated with blood pressure. N20 amplitudes and N9, N13, and N20 latencies did not differ between groups. In addition, plexus-to-cord, cord-to-cortex, and plexus-to-cortex conduction times were not different between groups. These data suggest that hypertension affects the peripheral nervous system by reducing the number of act... Psychophysiology journals http://www.medworm.com/rss/comments.php?id=3094365 Wed, 16 Dec 2009 00:00:00 +0100 3094365 http://www.medworm.com/index.php?rid=3094364&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2009.00940.x The influence of past traumatic experiences on the defense cascade in response to affective pictures was examined in survivors of war and torture. Trauma-exposed refugees with and without Posttraumatic Stress Disorder (PTSD) as well as healthy individuals viewed 75 pictures that varied in emotional content. Heart rate (HR) was recorded during the flickering stimulation of affective pictures in the context of a steady-state experiment. Whereas healthy controls showed the typical orienting response to aversive stimuli, PTSD patients reacted with an almost immediate increase in HR toward unpleasant pictures. Trauma-exposed participants without PTSD showed an indiscriminate orienting response regardless of picture category. The present findings argue for a faster flight/fight response to threa... Psychophysiology journals http://www.medworm.com/rss/comments.php?id=3094364 Wed, 16 Dec 2009 00:00:00 +0100 3094364 http://www.medworm.com/index.php?rid=3077480&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2009.00935.x In this study we describe optimal placement of bipolar electrodes based on a novel method and present results for lower facial muscles. We performed high-density sEMG recordings in 13 healthy participants. Raw sEMG signals were decomposed into motor unit action potentials (MUAPs). We positioned virtual electrode pairs in the interpolated monopolar MUAPs at different positions along muscle fiber direction and calculated the bipolar potentials. Electrode sites were determined where maximal bipolar amplitude was achieved and were validated. Objective guidelines for sEMG electrode placement improve the signal-to-noise ratio and may contribute to reduce cross talk, which is particularly important in the face. The method may be regarded as an important basis for improving the validity and reprod... Psychophysiology journals http://www.medworm.com/rss/comments.php?id=3077480 Fri, 11 Dec 2009 00:00:00 +0100 3077480 http://www.medworm.com/index.php?rid=3064923&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2009.00936.x Two experiments were conducted to examine whether the N2 component of the event-related potential (ERP), typically elicited in a S1-S2 matching task and considered to reflect mismatch process, can still be elicited when the S1 was imagined instead of perceived and to investigate how N2 amplitude varied with the degree of S1-S2 discrepancy. Three levels of discrepancy were defined by the degree of separation between the heard (S2) and imagined (S1) sounds. It was found that the N2 was reliably elicited when the perceived S2 differed from the imagined S1, but whether N2 amplitude increased with the degree of discrepancy depended in part on the S1-S2 discriminability (as evidenced by reaction time). Specifically, the effect of increasing discrepancy was attenuated as discriminability increase... Psychophysiology journals http://www.medworm.com/rss/comments.php?id=3064923 Tue, 08 Dec 2009 00:00:00 +0100 3064923 http://www.medworm.com/index.php?rid=3064927&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2009.00931.x This study investigated the relationship between autonomic cardiovascular reactivity and cardiac awareness during the following conditions: baseline, emotional picture viewing, mental stress, and heartbeat tracking. Cardiac parameters were examined by using power spectrum analysis of heart rate variability and impedance cardiography. According to their performance in a heartbeat tracking task, 38 participants were classified as good (n=19) or poor (n=19) heartbeat perceivers. Neither group differed during baseline and heartbeat tracking, but good compared to poor heartbeat perceivers demonstrated greater sympathetic reactivity during mental stress and more vagal reactivity and subjective arousal during emotional picture viewing. The results suggest that cardiac awareness is related to grea... Psychophysiology journals http://www.medworm.com/rss/comments.php?id=3064927 Mon, 07 Dec 2009 00:00:00 +0100 3064927 http://www.medworm.com/index.php?rid=3064926&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2009.00932.x We examined the locus of no-go interference on task-switching performance by comparing the event-related potential (ERP) time course of go/go and no-go/go sequences from cue onset to response execution. We also examined whether noninformative trials (i.e., delayed reconfiguration, no response inhibition) produce similar sequence effects. Participants switched using informative and noninformative cues (Experiment 2) intermixed with no-go trials (Experiment 1). Repeat RT was slower for both no-go/informative (pNG/I) and noninformative/informative (pNI/I) than informative/informative sequences. ERPs linked to anticipatory preparation showed no effect of trial sequence. ERPs indicated that pNG/I sequences reduce response readiness whereas pNI/I sequences reduce repetition benefit for repeat tr... Psychophysiology journals http://www.medworm.com/rss/comments.php?id=3064926 Mon, 07 Dec 2009 00:00:00 +0100 3064926 http://www.medworm.com/index.php?rid=3064925&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2009.00933.x This study aimed at differentiating between memory- and task-related processes and their correlates on the electrodermal and electrocortical level during information concealment. Variations of the Guilty Knowledge Test were implemented in two experiments while we measured skin conductance responses (SCRs) and event-related brain potentials. P300 amplitudes were specifically enhanced for items requiring a deviant behavioral response but they were not sensitive to concealed knowledge. In contrast, N200 amplitudes differed between memorized and irrelevant items in both experiments. SCR measures reflected a combined influence of task relevance and probe recognition, and they provided incremental validity above N200 amplitudes. These results suggest that the P300 mainly reflects task relevance ... Psychophysiology journals http://www.medworm.com/rss/comments.php?id=3064925 Mon, 07 Dec 2009 00:00:00 +0100 3064925 http://www.medworm.com/index.php?rid=3064924&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2009.00934.x Research has demonstrated that the jackknifing procedure for estimating ERP latencies (J. Miller, T. Patterson, & R. Ulrich, 1998) yields more accurate estimates of differences between experimental conditions in ERP latency than other methods. However, the scores resulting from this procedure require special adjustments for further analyses and do not directly reflect each participant's latency. Here, a simple transform is proposed that retrieves estimates of each participant's latency from the subaverage scores, rendering further adjustments superfluous. Other advantages of working with participants' latencies are discussed. Results of simulations support the validity of jackknifing and the retrieval transform. (Source: Psychophysiology) Psychophysiology journals http://www.medworm.com/rss/comments.php?id=3064924 Mon, 07 Dec 2009 00:00:00 +0100 3064924 http://www.medworm.com/index.php?rid=3010435&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2009.00930.x (Source: Psychophysiology) Psychophysiology journals http://www.medworm.com/rss/comments.php?id=3010435 Fri, 20 Nov 2009 00:00:00 +0100 3010435 http://www.medworm.com/index.php?rid=3010436&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2009.00929.x Negative feedback, either internal or external, is a fundamental guide to human learning and performance. The neural system that underlies the monitoring of performance and the adjustment of behavior has been subject to multiple neuroimaging investigations that uniformly implicate the anterior cingulate cortex and other prefrontal structures as crucial to these executive functions. The present article describes a series of experiments that employed event-related potentials to study a variety of processes associated with internal or external feedback. Three medial-frontal negativities (error-related negativity, correct-response negativity, feedback-related negativity) are highlighted, each of which plays an important role in the monitoring and dynamic adjustment of behavior. Extensions of b... Psychophysiology journals http://www.medworm.com/rss/comments.php?id=3010436 Thu, 19 Nov 2009 00:00:00 +0100 3010436 http://www.medworm.com/index.php?rid=2929067&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2009.00926.x Anxiety is characterized by cognitive biases, including attentional bias to emotional (especially threatening) stimuli. Accounts differ on the time course of attention to threat, but the literature generally confounds emotional valence and arousal and overlooks gender effects, both addressed in the present study. Nonpatients high in self-reported anxious apprehension, anxious arousal, or neither completed an emotion-word Stroop task during event-related potential (ERP) recording. Hypotheses differentiated time course of preferential attention to emotional stimuli. Individuals high in anxious apprehension and anxious arousal showed distinct early ERP evidence of preferential processing of emotionally arousing stimuli along with some evidence for gender differences in processing. Healthy con... Psychophysiology journals http://www.medworm.com/rss/comments.php?id=2929067 Tue, 27 Oct 2009 00:00:00 +0100 2929067 http://www.medworm.com/index.php?rid=2884597&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2009.00928.x Considerable progress has been made in our understanding of the remarkable fidelity with which the human auditory brainstem represents key acoustic features of the speech signal. The brainstem response to speech can be assessed noninvasively by examining scalp-recorded evoked potentials. Morphologically, two main components of the scalp-recorded brainstem response can be differentiated, a transient onset response and a sustained frequency-following response (FFR). Together, these two components are capable of conveying important segmental and suprasegmental information inherent in the typical speech syllable. Here we examine the putative neural sources of the scalp-recorded brainstem response and review recent evidence that demonstrates that the brainstem response to speech is dynamic in n... Psychophysiology journals http://www.medworm.com/rss/comments.php?id=2884597 Mon, 12 Oct 2009 23:00:00 +0100 2884597 http://www.medworm.com/index.php?rid=2884598&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2009.00927.x In conclusion, disturbed PPI in schizophrenia appears to result from deficits in selective attention, rather than from preattentive dysfunction. (Source: Psychophysiology) Psychophysiology journals http://www.medworm.com/rss/comments.php?id=2884598 Sun, 11 Oct 2009 23:00:00 +0100 2884598 http://www.medworm.com/index.php?rid=2873917&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2009.00923.x The affect-modulated acoustic startle response (ASR) might be a promising indicator for emotional reactivity as an endophenotype (an intermediate level between genetics and phenotypes), which we expected to be associated with the DRD4 polymorphism. Therefore, the affect-modulated ASR was examined in 114 healthy volunteers, 74 lacking the DRD4 7R allele (7R-absent group) and 41 with at least one DRD4 7R allele (7R group). Results revealed the well-known affect[ndash]modulated ASR in the 7R-absent group. The 7R group, however, was characterized by a blunted affect-modulated ASR, especially by a reduced startle potentiation toward unpleasant pictures. Associations between the exploratory assessed 5-HTT, COMT, and DAT polymorphisms and affect-modulated ASR were not found. Results speak for the... Psychophysiology journals http://www.medworm.com/rss/comments.php?id=2873917 Wed, 07 Oct 2009 23:00:00 +0100 2873917 http://www.medworm.com/index.php?rid=2873916&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2009.00924.x Attentional blink (AB) refers to the situation where the correct identification of a first target causes a processing deficit of a second target. The present study aims to clarify the stage at which the auditory AB occurs by means of scalp-recorded event-related potentials. On each trial, participants indicated whether predefined target sounds were presented in a rapid series of distractor sounds. The results showed a large AB when the presentation rate was fast. This auditory AB was paralleled by a suppression of the P3b wave to the second target. During the AB, the second target generated N1 and P2 waves, suggesting that some aspects of perceptual processing were preserved. The magnitude of the AB decreased with decreasing presentation rate. The improvement in detecting the second target... Psychophysiology journals http://www.medworm.com/rss/comments.php?id=2873916 Wed, 07 Oct 2009 23:00:00 +0100 2873916 http://www.medworm.com/index.php?rid=2873915&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2009.00925.x In this study we examined the specificity of the influence of video game experience on cognitive control. Participants with high and low video game experience performed the Stroop task while event-related brain potentials were recorded. The behavioral data revealed no difference between high and low gamers for the Stroop interference effect and a reduction in the conflict adaptation effect in high gamers. The amplitude of the medial frontal negativity and a frontal slow wave was attenuated in high gamers, and there was no effect of gaming status on the conflict slow potential. These data lead to the suggestion that video game experience has a negative influence on proactive, but not reactive, cognitive control. (Source: Psychophysiology) Psychophysiology journals http://www.medworm.com/rss/comments.php?id=2873915 Wed, 07 Oct 2009 23:00:00 +0100 2873915 http://www.medworm.com/index.php?rid=2802498&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2009.00885.x Principal components analysis (PCA) can facilitate analysis of event-related potential (ERP) components. Geomin, Oblimin, Varimax, Promax, and Infomax (independent components analysis) were compared using a simulated data set. Kappa settings for Oblimin and Promax were also systematically compared. Finally, the rotations were also analyzed in a two-step PCA procedure, including a contrast between spatiotemporal and temporospatial procedures. Promax was found to give the best overall results for temporal PCA, and Infomax was found to give the best overall results for spatial PCA. The current practice of kappa values of 3 or 4 for Promax and 0 for Oblimin was supported. Source analysis was meaningfully improved by temporal Promax PCA over the conventional windowed difference wave approach (f... Psychophysiology journals http://www.medworm.com/rss/comments.php?id=2802498 Wed, 16 Sep 2009 23:00:00 +0100 2802498 http://www.medworm.com/index.php?rid=2802503&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2009.00880.x We previously reported a novelty P3 reduction in depressed patients compared to healthy controls (n=20 per group) in a novelty oddball task using a 31-channel montage. In an independent replication and extension using a 67-channel montage (n=49 per group), reference-free current source density (CSD) waveforms were simplified and quantified by a temporal, covariance-based principal components analysis (PCA) (unrestricted Varimax rotation), yielding factor solutions consistent with other oddball tasks. A factor with a loadings peak at 343 ms summarized the target P3b source as well as a secondary midline frontocentral source for novels and targets. An earlier novelty vertex source (NVS) at 241 ms was present for novels, but not targets, and was reduced in patients. Compatible CSD-PCA finding... Psychophysiology journals http://www.medworm.com/rss/comments.php?id=2802503 Mon, 14 Sep 2009 23:00:00 +0100 2802503 http://www.medworm.com/index.php?rid=2802502&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2009.00881.x The face inversion effect (FIE) refers to a disproportionate disruption of the processing of face information by inverting faces. We investigated the FIE in epilepsy patients by simultaneous intracranial and scalp recordings of event-related potentials (ERPs). In scalp recordings, a typical FIE on ERPs was observed with increased latencies and amplitudes of the positive counterpart of the occipito-temporal N170, namely, the vertex positive potential (VPP), in response to inverted faces. Similar amplitude and latency increases were revealed for the intracranial N200 recorded over face-sensitive and non-face-sensitive areas in the lateral occipital cortex, but not in the ventral temporal cortex. Peak latencies did not differ between the scalp VPP and intracranial N200. Findings indicate that... Psychophysiology journals http://www.medworm.com/rss/comments.php?id=2802502 Mon, 14 Sep 2009 23:00:00 +0100 2802502 http://www.medworm.com/index.php?rid=2802501&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2009.00882.x The present study examined the effects of cigarette smoking on attentional processing by measuring nondeprived smokers' (n=39), minimally deprived smokers' (n=36), and nonsmokers' (n=34) startle eyeblink reflex, heart rate, and skin conductance responses (SCR) to acoustic startle stimuli (105 dB) during directed attention tasks. Whereas smokers demonstrated smaller startle responses than nonsmokers during a directed attention visual task, no difference in startle response magnitude emerged between the two smoking groups, nor did we observe an effect of smoking on SCR or heart rate response to the startle stimuli. Our findings suggest that smokers differ from nonsmokers in their selective attention abilities and that smoking does not enhance minimally deprived smokers' selective attention. ... Psychophysiology journals http://www.medworm.com/rss/comments.php?id=2802501 Mon, 14 Sep 2009 23:00:00 +0100 2802501 http://www.medworm.com/index.php?rid=2802500&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2009.00883.x We recently introduced an accurate and countermeasure (CM)-resistant P300-based deception detection test (J.P. Rosenfeld et al., 2008). When subjects use CMs to all irrelevant items in the test, the probe P300 is increased rather than reduced, as in previous P300-based deception protocols, allowing detection of CM users. Evidence herein suggests this is partly due to an omit effect; the probe was the only uncountered item. Three groups were tested: a guilty omit probe group performed an explicit response to each irrelevant item but not to the probe, an innocent omit irrelevant group saw only irrelevant items and omitted a response to one item, and a guilty no omit group had a concealed information item as probe and performed an explicit response to each. We found a greater P300 amplitude t... Psychophysiology journals http://www.medworm.com/rss/comments.php?id=2802500 Mon, 14 Sep 2009 23:00:00 +0100 2802500 http://www.medworm.com/index.php?rid=2802499&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2009.00884.x Thinking is biological work and involves the allocation of cognitive resources. The aim of this study was to investigate the impact of fluid intelligence on the allocation of cognitive resources while one is processing low-level and high-level cognitive tasks. Individuals with high versus average fluid intelligence performed low-level choice reaction time tasks and high-level geometric analogy tasks. We combined behavioral measures to examine speed and accuracy of processing with pupillary measures that indicate resource allocation. Individuals with high fluid intelligence processed the low-level choice reaction time tasks faster than normal controls. The task-evoked pupillary responses did not differ between groups. Furthermore, individuals with high fluid intelligence processed the high-... Psychophysiology journals http://www.medworm.com/rss/comments.php?id=2802499 Mon, 14 Sep 2009 23:00:00 +0100 2802499 http://www.medworm.com/index.php?rid=2780366&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2009.00874.x Asymmetries in posterior ERP components, such as the N1, are generally taken to reflect the visual processing of spatial information in absolute (fixation-based) coordinates. Yet, it is also well established that the position of an object can be coded relative to the position of other objects. To examine the ERP correlates of relative spatial coding, two experiments were conducted in which spatially neutral target stimuli were preceded, accompanied, or followed by laterally presented, task-irrelevant accessory stimuli. Targets presented simultaneously with a lateral accessory evoked, despite physical asymmetry, a bilateral, symmetric N1. Targets that followed the accessory evoked, despite physical symmetry, an asymmetric N1, with a maximum contralateral to the accessory N1. Thus, lateraliz... Psychophysiology journals http://www.medworm.com/rss/comments.php?id=2780366 Wed, 09 Sep 2009 23:00:00 +0100 2780366 http://www.medworm.com/index.php?rid=2706838&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2009.00873.x Although previous findings suggest that motor preparation can be initiated unconsciously, there is some debate as to whether inhibitory control can occur unconsciously. Results from research involving response conflict points to an association between inhibitory control and conscious awareness. However, no previous research has assessed whether unconscious information can influence brain activity correlates of inhibition when a response must be completely withheld. We recorded event-related potentials (ERPs) in a go/no-go task with subliminal primes and demonstrated that inhibition-related ERP components were modulated as a function of the congruency of the primes. Furthermore, these ERP modulations were directly related to the extent to which participants' performance was influenced by th... Psychophysiology journals http://www.medworm.com/rss/comments.php?id=2706838 Mon, 17 Aug 2009 23:00:00 +0100 2706838 http://www.medworm.com/index.php?rid=2680265&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2009.00879.x Previous research has demonstrated that the maintenance of visual information in working memory is associated with a sustained posterior contralateral negativity. Here we show that this component is also elicited during the spatially selective access to visual working memory. Participants memorized a bilateral visual search array that contained two potential targets on the left and right side. The task-relevant side was signalled by post-cues that were presented either 150 ms after array offset or after a longer interval (700[ndash]1000 ms). Enhanced negativities at posterior electrodes contralateral to the cued side of a target were elicited in response to both early and late post-cues, suggesting that they reflect not only memory maintenance, but also processes involved in the access to ... Psychophysiology journals http://www.medworm.com/rss/comments.php?id=2680265 Fri, 07 Aug 2009 23:00:00 +0100 2680265 http://www.medworm.com/index.php?rid=2680274&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2009.00868.x This study examined how valence and arousal affect the processes linked to subsequent memory for emotional information. While undergoing an fMRI scan, participants viewed neutral pictures and emotional pictures varying by valence and arousal. After the scan, participants performed a recognition test. Subsequent memory for negative or high arousal information was associated with occipital and temporal activity, whereas memory for positive or low arousal information was associated with frontal activity. Regression analyses confirmed that for negative or high arousal items, temporal lobe activity was the strongest predictor of later memory whereas for positive or low arousal items, frontal activity corresponded most strongly with later memory. These results suggest that the types of encoding ... Psychophysiology journals http://www.medworm.com/rss/comments.php?id=2680274 Thu, 06 Aug 2009 23:00:00 +0100 2680274 http://www.medworm.com/index.php?rid=2680273&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2009.00869.x The present study used behavioral and electrophysiological measures to investigate the processes mediating long-term recognition memory for emotional and neutral pictures. The results show enhanced memory recollection for emotional arousing pictures compared to neutral low arousing pictures. In accordance with the behavioral data, we observed enhanced old/new effects in the ERPs for emotionally arousing pictures in the recollection-sensitive old/new component at centro-parietal sites (500[ndash]800 ms). Moreover, early old/new effects were present over frontal and parietal sites (300[ndash]500 ms) irrespective of picture contents. Analysis of the subjective awareness, indexed by the confidence ratings, showed that the late parietal old/new effect was increased for high confidence responses... Psychophysiology journals http://www.medworm.com/rss/comments.php?id=2680273 Thu, 06 Aug 2009 23:00:00 +0100 2680273 http://www.medworm.com/index.php?rid=2680272&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2009.00870.x We examined whether effects of prior experience are mediated by distinct brain processes from those processing current stimulus features. We recorded event-related potentials (ERPs) during an auditory stream segregation task that presented an adaptation sequence with a small, intermediate, or large frequency separation between low and high tones ([Delta]f), followed by a test sequence with intermediate [Delta]f. Perception of two streams during the test was facilitated by small prior [Delta]f and by prior perception of two streams and was accompanied by more positive ERPs. The scalp topography of these perception-related changes in ERPs was different from that observed for ERP modulations due to increasing the current [Delta]f. These results reveal complex interactions between stimulus-dri... Psychophysiology journals http://www.medworm.com/rss/comments.php?id=2680272 Thu, 06 Aug 2009 23:00:00 +0100 2680272 http://www.medworm.com/index.php?rid=2680271&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2009.00871.x Altered affective processing has been proposed as mediating between early life stress (ELS) and subsequent psychopathology. The present study examined whether ELS influences affective cortical processing differently in psychiatric patients and healthy subjects. The number of stressful experiences before onset of puberty was assessed in 50 inpatients with diagnoses of Major Depressive Disorder, schizophrenia, drug addiction, or Borderline Personality Disorder and in 20 healthy comparison subjects. Subjects monitored pleasant, neutral, and unpleasant pictures during magnetoencephalographic recording. Suppression of right-posterior activity 160[ndash]210 ms after stimulus onset was associated with certain diagnoses and high ELS. Results confirmed specific contributions of ELS versus adult str... Psychophysiology journals http://www.medworm.com/rss/comments.php?id=2680271 Thu, 06 Aug 2009 23:00:00 +0100 2680271 http://www.medworm.com/index.php?rid=2680270&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2009.00872.x Task- and personality-related modulations of the N2 were probed within the framework of the revised Reinforcement Sensitivity Theory (RST). Using an appetitive choice task, we investigated 58 students with extreme scores on the behavioral inhibition system and behavioral approach system (BIS/BAS) scales. The baseline-to-peak N2 amplitude was sensitive to the strength of decision conflict and demonstrated RST-related personality differences. In addition to the baseline N2 amplitude, temporal PCA results suggested two N2 components accounting for a laterality effect and capturing different N2 patterns for BIS/BAS groups with increasing conflict level. Evidence for RST-related personality differences was obtained for baseline-to-peak N2 and tPCA components in the present task. The results sup... Psychophysiology journals http://www.medworm.com/rss/comments.php?id=2680270 Thu, 06 Aug 2009 23:00:00 +0100 2680270 http://www.medworm.com/index.php?rid=2680269&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2009.00875.x When speakers hear the fundamental frequency (F0) of their voice altered, they shift their F0 in the direction opposite the perturbation. The current study used ERPs to examine sensory processing of short feedback perturbations during an ongoing utterance. In one session, participants produced a vowel at an F0 of their own choosing. In another session, participants matched the F0 of a cue voice. An F0 perturbation of 0, 25, 50, 100, or 200 cents was introduced for 100 ms. A mismatch negativity (MMN) was observed. Differences between sessions were only found for 200-cent perturbations. Reduced compensation when speakers experienced the 200-cent perturbations suggests that this larger perturbation was perceived as externally generated. The presence of an MMN, and no earlier (N100) response s... Psychophysiology journals http://www.medworm.com/rss/comments.php?id=2680269 Thu, 06 Aug 2009 23:00:00 +0100 2680269 http://www.medworm.com/index.php?rid=2680268&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2009.00876.x P3 amplitude reduction (P3-AR) is associated with biological vulnerability to a spectrum of externalizing disorders, such as ADHD, conduct disorder, and substance use disorders. P3, however, is generally characterized as a broad activation involving multiple neurophysiological processes. One approach to separating P3-related processes is time-frequency (TF) analysis. The current study used a novel PCA-based TF analysis method to investigate relationships between P3, its associated TF components, and externalizing in a community-based sample of adolescent males. Results showed that 1) alone, P3 and each TF-PCA derived component could successfully discriminate diagnostic groups from controls, and 2) delta components in specific time ranges accounted for variance beyond that accounted for by ... Psychophysiology journals http://www.medworm.com/rss/comments.php?id=2680268 Thu, 06 Aug 2009 23:00:00 +0100 2680268 http://www.medworm.com/index.php?rid=2680267&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2009.00877.x Activity in the anterior cingulate cortex (ACC) has been linked to the processes of error detection and conflict monitoring, along with the subsequent engagement of cognitive-control mechanisms. The error-related negativity (ERN) is an electrophysiological signal associated with this ACC monitoring process, occurring approximately 100 ms after an error is made. The current study examined the possibility that individual differences in ERN magnitude would predict performance outcomes related to cognitive control. Undergraduate students completed a color-naming Stroop task while their neural activity was recorded via electroencephalogram. Results indicated that a larger ERN following errors was significantly correlated with better academic performance as measured by official student transcrip... Psychophysiology journals http://www.medworm.com/rss/comments.php?id=2680267 Thu, 06 Aug 2009 23:00:00 +0100 2680267 http://www.medworm.com/index.php?rid=2680266&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2009.00878.x The lateralized readiness potential (LRP) is a component of average event-related potentials that has proven very useful in the study of hand-specific motor preparation. We developed a model of single-trial LRP waveforms that produces realistic average waveforms for both stimulus-locked and response-locked averaging. This model may be useful in computer simulation studies of LRP scoring methods, and it may open up the possibility of ultimately retrieving trial-by-trial information about LRP activity. (Source: Psychophysiology) Psychophysiology journals http://www.medworm.com/rss/comments.php?id=2680266 Thu, 06 Aug 2009 23:00:00 +0100 2680266 http://www.medworm.com/index.php?rid=2651940&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2009.00865.x In a common version of the Simon task, the subjects respond by a left- or a right-hand key press to the color of a stimulus (S) presented to the left or right of a fixation point. Albeit S location is irrelevant, the incorrect response is more often activated when the required response is contralateral to the S (incongruent) than when it is ipsilateral to the S (congruent). The aim of the present study was to decipher the respective contributions of S-response key location correspondence and S-hand correspondence to such incorrect activations (IAs). The subjects were required to perform a Simon task with the arms not crossing and crossing the median plane. Present for both arm placements, the difference in the frequency of IAs between incongruent and congruent responses was smaller when th... Psychophysiology journals http://www.medworm.com/rss/comments.php?id=2651940 Wed, 29 Jul 2009 23:00:00 +0100 2651940 http://www.medworm.com/index.php?rid=2651941&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2009.00857.x We report the results of two experiments designed to clarify the spatial and temporal characteristics of the positive deflection that follows the error related negativity (ERN) elicited to incorrect responses in speeded reaction time tasks. Principal components analysis (PCA) indicates that the positive deflection reported to follow the ERN is composed of two different components: (a) a fronto-cental positive deflection that follows the ERN and shares its spatial distribution and (b) a P300. When accuracy was required of the participants, the ERN and the P300 were larger in amplitude than when speed and accuracy were equally weighted. On the other hand, the amplitude of the fronto-central positive component was not affected by the degree to which accuracy was stressed. (Source: Psychophysi... Psychophysiology journals http://www.medworm.com/rss/comments.php?id=2651941 Tue, 28 Jul 2009 23:00:00 +0100 2651941 http://www.medworm.com/index.php?rid=2623752&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2009.00856.x The current review constitutes the first comprehensive look at the possibility that the mismatch negativity (MMN, the deflection of the auditory ERP/ERF elicited by stimulus change) might be generated by so-called fresh-afferent neuronal activity. This possibility has been repeatedly ruled out for the past 30 years, with the prevailing theoretical accounts relying on a memory-based explanation instead. We propose that the MMN is, in essence, a latency- and amplitude-modulated expression of the auditory N1 response, generated by fresh-afferent activity of cortical neurons that are under nonuniform levels of adaptation. (Source: Psychophysiology) Psychophysiology journals http://www.medworm.com/rss/comments.php?id=2623752 Tue, 21 Jul 2009 23:00:00 +0100 2623752 http://www.medworm.com/index.php?rid=2574713&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2009.00859.x Aging has been shown to increase sensory thresholds for a variety of exteroceptive and proprioceptive stimuli. However, the influence of aging on interoceptive awareness has received relatively little empirical attention. Here we report an inverse association between aging and interoception, as indexed by the ability to sense the heartbeat at rest. In a group of 59 participants ranging in age from 22 to 63 years, age inversely predicted heartbeat detection ability, both within and across several measurement sessions. On average, age accounted for 30% of the variance in heartbeat detection accuracy. Other attribute variables including body mass index and sex were not related to heartbeat detection ability. These findings provide clear empirical evidence that interoception, much like exteroc... Psychophysiology journals http://www.medworm.com/rss/comments.php?id=2574713 Mon, 06 Jul 2009 23:00:00 +0100 2574713 http://www.medworm.com/index.php?rid=2565599&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2009.00867.x Because expectancies play a central role in current theories of dopaminergic neuron function, it is important to develop measures of reward anticipation processes. In the present study, reflexogenic bursts of white noise were presented to 39 healthy young adults as they awaited rewards and punishments in a gambling-like task. The rewards were small pieces of chocolate; the punishments, segments of bitter-tasting banana peel. Consistent with prior research on affective valence, postauricular reflexes were larger prior to rewards than punishments, whereas the reverse was true for acoustic blink reflexes. We theorized that potentiation of the postauricular reflex prior to consuming appetizing food is related to the priming of ear-retraction musculature during nursing in our remote ancestors. ... Psychophysiology journals http://www.medworm.com/rss/comments.php?id=2565599 Sat, 04 Jul 2009 23:00:00 +0100 2565599 http://www.medworm.com/index.php?rid=2565607&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2009.00854.x Dual-task performance requires flexible attention allocation to two or more streams of information. Dorsolateral prefrontal cortex (DLPFC) is considered important for executive function, and recent modeling work proposes that attention control may arise from selective activation and inhibition of different processing units within this region. Here, we used a tone discrimination task and a visual letter memory task to examine whether this type of competition could be measurable using a neuroimaging technique, the event-related optical signal, with high spatial and temporal resolution. Left and right DLPFC structures were differentially affected by task priority and load, with the left middle frontal gyrus (MFG) being preferentially recruited by the visual memory task, whereas the two tasks ... Psychophysiology journals http://www.medworm.com/rss/comments.php?id=2565607 Tue, 30 Jun 2009 23:00:00 +0100 2565607 http://www.medworm.com/index.php?rid=2565606&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2009.00858.x The present study explored the relationship between inhibition of return (IOR) and visual processes by seeking evidence that IOR and changes in event-related potential (ERP) indices of occipital cortex activity covary in response to experimental manipulation. The presence or absence of a central reorienting event was manipulated within the context of a cue[ndash]target experiment. When a reorienting event was presented in the interval between cue and target, IOR was accompanied by reductions in the amplitudes of early occipital ERP peaks on validly cued trials relative to invalidly cued trials. When a reorienting event was not presented, neither IOR nor modulations of the occipital ERP peaks was observed. These results provide strong evidence that IOR arises from changes in occipital visua... Psychophysiology journals http://www.medworm.com/rss/comments.php?id=2565606 Tue, 30 Jun 2009 23:00:00 +0100 2565606 http://www.medworm.com/index.php?rid=2565605&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2009.00860.x An arrow version of the Eriksen flanker task was employed to investigate the influence of conflict on the error-related negativity (ERN). The degree of conflict was modulated by varying the distance between flankers and the target arrow (CLOSE and FAR conditions). Error rates and reaction time data from a behavioral experiment were used to adapt a connectionist model of this task. This model was based on the conflict monitoring theory and simulated behavioral and event-related potential data. The computational model predicted an increased ERN amplitude in FAR incompatible (the low-conflict condition) compared to CLOSE incompatible errors (the high-conflict condition). A subsequent ERP experiment confirmed the model predictions. The computational model explains this finding with larger post... Psychophysiology journals http://www.medworm.com/rss/comments.php?id=2565605 Tue, 30 Jun 2009 23:00:00 +0100 2565605 http://www.medworm.com/index.php?rid=2565604&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2009.00861.x This study examines similarities and differences in fear potentiation between two protective reflexes: cardiac defense and eyeblink startle. Women reporting intense fear of animals but low fear of blood or intense fear of blood but low fear of animals viewed pictures depicting blood or the feared animal for 6 s in 2 separate trials in counterbalanced order. An intense burst of white noise, able to elicit both a cardiac defense response and a reflexive startle blink, was presented 3.5 s after picture onset. Both cardiac and blink responses were potentiated when highly fearful individuals viewed fearful pictures. However, differences appeared concerning picture order. This pattern of results indicates communalities and differences among protective reflexes that are relevant for understanding... Psychophysiology journals http://www.medworm.com/rss/comments.php?id=2565604 Tue, 30 Jun 2009 23:00:00 +0100 2565604 http://www.medworm.com/index.php?rid=2565603&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2009.00862.x Female undergraduates performed an easy (fatigue low) or difficult (fatigue high) scanning task and then were presented mental arithmetic problems with instructions that they would earn a high or low chance of winning a prize if they did as well as or better than 50% of those who had performed previously. As expected, blood pressure responses in the second work period rose or tended to rise with fatigue where the chance of winning was high. By contrast, the responses tended weakly to decline with fatigue where the chance of winning was low. The pressure findings support the suggestion of a recent fatigue analysis that success importance should moderate fatigue influence on CV responses to a challenge so long as fatigued performers view success as possible. They also conceptually replicate ... Psychophysiology journals http://www.medworm.com/rss/comments.php?id=2565603 Tue, 30 Jun 2009 23:00:00 +0100 2565603 http://www.medworm.com/index.php?rid=2565602&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2009.00863.x The purpose was to assess the validity of predicting peak oxygen uptake from Ratings of Perceived Exertion (RPE)[le]15, during a graded exercise test (GXT), in obese women. Forty-three obese women performed GXT to volitional exhaustion. During GXT, oxygen uptake and RPE were measured. Individual linear regressions between and RPE[le]15 were extrapolated to RPE 20 in order to predict . Actual and predicted were not significantly different (13.9±3.0 vs 14.2±3.3 ml kg[minus]1 min[minus]1, respectively; p=.26). The Pearson product moment correlation between actual and predicted was high (r=0.82). The 95% limits of agreement analysis on these values (bias±1.96SD) was [minus]0.3±3.7 ml kg[minus]1 min[minus]1. Results suggested that RPE[le]15 elicited during a sub-maximal GXT provides accurat... Psychophysiology journals http://www.medworm.com/rss/comments.php?id=2565602 Tue, 30 Jun 2009 23:00:00 +0100 2565602 http://www.medworm.com/index.php?rid=2565601&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2009.00864.x To examine when in the perception-action cycle resolving information-processing conflict modulates signals of the current need for cognitive control, the present work examined event-related potential correlates of response preparation (lateralized readiness potentials; LRPs) and of information-processing conflict (fronto-central N2 responses) on trial n flanker trials, as a function of whether trial n[ndash]1 entailed a congruent flanker, an incongruent flanker, or a NoGo cue. Although LRP-indexed erroneous response preparation was substantial on incongruent trials across all levels of trial n[ndash]1, N2 amplitudes and behavioral interference effects were attenuated on incongruent trials following NoGo and incongruent (relative to congruent) trials. Even after initial attentional and moto... Psychophysiology journals http://www.medworm.com/rss/comments.php?id=2565601 Tue, 30 Jun 2009 23:00:00 +0100 2565601 http://www.medworm.com/index.php?rid=2565600&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2009.00866.x Preparing for a cued, speeded response induces a set of physiological changes. A review of the psychophysiology of preparation suggested that inhibition of action was an important process among the constellation of changes constituting attentive preparation. The current experiment combined event-related functional magnetic resonance imaging and cardiac inter-beat interval measures in an experiment that compared preparing for a response, watching stimuli without responding, and responding in the absence of preparation. Ten college-aged participants were tested in an initial psychophysiological experiment followed by two scanning sessions during which reverse spiral imaging was performed concurrent with inter-beat interval measurement. Two analytic approaches were used to confirm blood oxyge... Psychophysiology journals http://www.medworm.com/rss/comments.php?id=2565600 Tue, 30 Jun 2009 23:00:00 +0100 2565600 http://www.medworm.com/index.php?rid=2492232&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2009.00848.x The error-related negativity (ERN) and error positivity (Pe) are increasingly being examined as neural correlates of response monitoring. The minimum number of error trials included in grand averages varies across studies; indeed, there has not been a systematic investigation on the number of trials required to obtain a stable ERN and Pe. In the current study, the ERN and Pe were quantified as two random trials were added to participants' (N=53) ERP averages. Adding trials increased the correlation with the grand average ERN and Pe; however, high correlations (rs>.80) were obtained with only 6 trials. Internal reliability of the ERN and Pe reached moderate levels after 6 and 2 trials and the signal-to-noise ratio of the ERN and Pe did not change after 8 and 4 trials, respectively. Combined... Psychophysiology journals http://www.medworm.com/rss/comments.php?id=2492232 Wed, 24 Jun 2009 23:00:00 +0100 2492232 http://www.medworm.com/index.php?rid=2492237&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2009.00851.x We examined aspects of emotional empathy across different physiological response systems in boys with disruptive behavior disorders (DBD) and normal controls. Heart rate (HR) and electromyographic (EMG) reactivity in zygomaticus major and corrugator supercilii muscles were monitored during sadness-, anger-, or happiness-inducing film clips. Relative to controls, DBD boys showed significantly less HR reduction during sadness, and a smaller increase in corrugator EMG activity both during sadness and anger. No significant group differences emerged in HR and zygomaticus EMG responsivity during happiness. We also examined cardiac activity at rest and found higher resting HR and lower respiratory sinus arrhythmia in DBD boys compared to controls. Findings give evidence for a selective impairment... Psychophysiology journals http://www.medworm.com/rss/comments.php?id=2492237 Sun, 21 Jun 2009 23:00:00 +0100 2492237 http://www.medworm.com/index.php?rid=2492236&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2009.00850.x In this report, we describe the use of recent advancements in biometric modeling to examine changes in the genetic and environmental contributions to variability in P3 amplitude related to cumulative AAU by late adolescence in a large community-based twin sample. We found that the genetic and environmental contributions to variability in P3 amplitude were unaffected by AAU. This suggests that P3AR indexes risk for alcoholism independent of any deleterious effect of AAU on adolescent brain development. (Source: Psychophysiology) Psychophysiology journals http://www.medworm.com/rss/comments.php?id=2492236 Sun, 21 Jun 2009 23:00:00 +0100 2492236 http://www.medworm.com/index.php?rid=2492235&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2009.00852.x Researchers examining skin conductance (SC) as a measure of aversive conditioning commonly separate the SC response into two components when the CS-UCS interval is sufficiently long. This convention drew from early theorists who described these components, the first- and second-interval responses, as measuring orienting and conditional responses, respectively. The present report critically examines this scoring method through a literature review and a secondary data analysis of a large-scale study of police and firefighter trainees that used a differential aversive conditioning procedure (n=287). The task included habituation, acquisition, and extinction phases, with colored circles as the CSs and shocks as the UCS. Results do not support the convention of separating the SC response into f... Psychophysiology journals http://www.medworm.com/rss/comments.php?id=2492235 Sun, 21 Jun 2009 23:00:00 +0100 2492235 http://www.medworm.com/index.php?rid=2492234&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2009.00853.x We compared early stages of face processing in young and older participants as indexed by ERPs elicited by faces and non-face stimuli presented in upright and inverted orientations. The P1 and N170 components were larger in older than in young participants. However, the early distinction between stimulus categories as reflected by N170 face was similar across groups. Face inversion increased and delayed the N170 peak in the younger group while in older participants inversion delayed the N170 peak but had no effect on amplitude. The N170 amplitude was right-lateralized in the young, but not in the older group. Yet, the difference between the N170 elicited by faces and non-face stimuli was similarly right-lateralized in both groups. These data suggest that detection of faces and their stream... Psychophysiology journals http://www.medworm.com/rss/comments.php?id=2492234 Sun, 21 Jun 2009 23:00:00 +0100 2492234 http://www.medworm.com/index.php?rid=2492233&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2009.00855.x In the present study we provide the first empirical evidence that viscero-sensory feedback from an internal organ is associated with decision-making processes. Participants with accurate vs. poor perception of their heart activity were compared with regard to their performance in the Iowa Gambling Task. During this task, participants have to choose between four card decks. Decks A and B yield high gains and high losses, and if played continuously, result in net loss. In contrast, decks C and D yield small gains and also small losses, but result in net profit if they are selected continuously. Accordingly, participants have to learn to avoid the net loss options in favor of the net gain options. In our study, participants with good cardiac perception chose significantly more of the net gain... Psychophysiology journals http://www.medworm.com/rss/comments.php?id=2492233 Sun, 21 Jun 2009 23:00:00 +0100 2492233 http://www.medworm.com/index.php?rid=2465954&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2009.00849.x An aggressive personality style has been proposed to arise from a cortical asymmetry between the left and right frontal hemispheres. In the present transcranial magnetic stimulation (TMS) study, evidence was sought for a link between an aggressive personality style and functional interhemispheric connectivity between the left and right frontal cortices. Functional interhemispheric connectivity was measured by determining transcallosal inhibition (TCI) using TMS in 20 healthy right-handed volunteers, who were given the Buss[ndash]Perry Aggression Questionnaire (AQ) and a selective attention task. Analyses showed higher levels of left-to-right TCI significantly correlated with higher AQ scores. Furthermore, increased left-to-right together with reduced right-to-left TCI was associated with a... Psychophysiology journals http://www.medworm.com/rss/comments.php?id=2465954 Tue, 09 Jun 2009 04:00:00 +0100 2465954 http://www.medworm.com/index.php?rid=2465957&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2009.00845.x P50, N100, and P200 auditory sensory gating could reflect mechanisms involved in protecting higher-order cognitive functions, suggesting relationships between sensory gating and cognition. This hypothesis was tested in 56 healthy adults who were administered the paired-click paradigm and two adaptations of the continuous performance test (Immediate/Delayed Memory Task, IMT/DMT). Stronger P50 gating correlated with fewer commission errors and prolonged reaction times on the DMT. Stronger N100 and P200 gating correlated with better discriminability on the DMT. Finally, prolonged P200 latency related to better discriminability on the IMT. These findings suggest that P50, N100, and P200 gating could be involved in protecting cognition by affecting response bias, behavioral inhibition, working ... Psychophysiology journals http://www.medworm.com/rss/comments.php?id=2465957 Mon, 08 Jun 2009 04:00:00 +0100 2465957 http://www.medworm.com/index.php?rid=2465956&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2009.00844.x One key issue for computational models of visual-word recognition is the time course of orthographic and phonological information during reading. Previous research, using both behavioral and event related brain potential (ERP) measures, has shown that orthographic codes are activated very early but that phonological activation starts to occur immediately afterward. Here we report an ERP masked priming experiment in Spanish that investigates this issue further by using very strict control conditions. The critical phonological comparison was between two pairs of primes having the same orthographic similarity to the target words but differing in phonological similarity (e.g., conal-CANAL vs. cinal-CANAL vis à vis ponel-PANEL vs. pinel-PANEL), whereas the critical orthographic contrast was be... Psychophysiology journals http://www.medworm.com/rss/comments.php?id=2465956 Mon, 08 Jun 2009 04:00:00 +0100 2465956 http://www.medworm.com/index.php?rid=2465955&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2009.00847.x Avoiding reflexive saccades triggered by salient yet task-irrelevant stimuli requires the engagement of control processes that inhibit attention toward irrelevant objects and prevent reflex-like oculomotor action. In the current study participants made saccades to visual targets to the left and right of fixation as directed by target appearance. A distractor could either be presented in the same (congruent trials) or the opposite hemifield (incongruent trials) as the target. Trial context was manipulated, creating risky (mostly incongruent blocks), safe (mostly congruent blocks), or neutral conditions. Electroencephalogram was measured to examine if any contextual modulations would be reflected in the N2 peak frequently associated with performance monitoring. The results are discussed with... Psychophysiology journals http://www.medworm.com/rss/comments.php?id=2465955 Mon, 08 Jun 2009 04:00:00 +0100 2465955 http://www.medworm.com/index.php?rid=2450425&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2009.00846.x Localized attentional interference (LAI) occurs when attending to a visual object degrades processing of nearby objects. Competitive interaction accounts of LAI explain the phenomenon as the result of competition among objects for representation in extrastriate cortex. Here, we examined the N2pc component of the event-related potential (ERP) as a likely neural correlate of LAI. In Experiment 1, participants responded to the orientation of a target while ignoring a nearby decoy. At small target[ndash]decoy separations, N2pc amplitude was attenuated whereas the amplitude of a later, positive component (Ptc) was potentiated. Experiment 2 ruled out sensory explanations of these effects. The N2pc results are consistent with the idea that spatially mediated competition for representation in extr... Psychophysiology journals http://www.medworm.com/rss/comments.php?id=2450425 Tue, 02 Jun 2009 04:00:00 +0100 2450425 http://www.medworm.com/index.php?rid=2444462&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2009.00843.x This study examined, in a large community sample, the cross-sectional and prospective associations between reactivity and self-reported health. Blood pressure and heart rate were measured at rest and in response to an arithmetic stress task. Self-reported health was assessed concurrently and 5 years later. In cross-sectional analyses, those with excellent/good self-reported health exhibited larger cardiovascular reactions than those with fair/poor subjective health. In prospective analyses, participants who had larger cardiovascular reactions to stress were more likely to report excellent/good health 5 years later, taking into account their reported health status at the earlier assessment. The findings suggest that greater cardiovascular reactivity may not always be associated with negativ... Psychophysiology journals http://www.medworm.com/rss/comments.php?id=2444462 Sat, 30 May 2009 04:00:00 +0100 2444462 http://www.medworm.com/index.php?rid=2444466&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2009.00834.x Conclusions about the cognitive and neural requirements of saccade control may differ as a result of stimulus presentation method. This issue was examined in the current study by evaluating behavioral differences in pro- and antisaccade responses among 12 healthy young adults as a function of task presentation method, length of cue-to-target interval, and previous trial type. A 1-s cue-to-target interval fostered goal neglect, indicated by an increase in uncorrected errors and reaction times for "error" saccades. There was also a strong relationship between speed of visual orienting (prosaccade latencies) and failed inhibition (antisaccade errors) for the simultaneous condition. Interestingly, only the simultaneous condition produced task switch costs (on saccade latencies and error respon... Psychophysiology journals http://www.medworm.com/rss/comments.php?id=2444466 Thu, 28 May 2009 04:00:00 +0100 2444466 http://www.medworm.com/index.php?rid=2444465&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2009.00837.x A component of the event-related magnetic field (ERMF) response was observed in magnetoencephalographic signals recorded during the maintenance of information in visual short-term memory (VSTM). This sustained posterior contralateral magnetic (SPCM) field is likely the magnetic equivalent of the sustained posterior contralateral negativity (SPCN) found in electrophysiology. Magnetoencephalography data showed, at the sensor level, a bilateral activation over the parietal cortex that increased in amplitude for higher memory load. Others sensors, also over the parietal cortex, showed an activation pattern similar to the SPCN with higher activation for the hemisphere contralateral to the visual field from which visual information was encoded. These two activation patterns suggest that the SPCN... Psychophysiology journals http://www.medworm.com/rss/comments.php?id=2444465 Thu, 28 May 2009 04:00:00 +0100 2444465 http://www.medworm.com/index.php?rid=2444464&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2009.00838.x This study examined developmental differences in the ERP correlates of internal and external error processing (ERN and FRN) during learning. A probabilistic learning task was applied in which feedback validity was manipulated. The behavioral data showed similar accuracy for children and adults when feedback was valid, whereas age differences were obtained when it was partially invalid. We found no reduction of the ERN for children compared to adults when performance levels were equated. Yet, contrary to adults, children did not differentiate between responses when feedback was partially invalid, indicating that they are less able to represent the correctness of a response when there is interference during learning. Moreover, we found a larger FRN and reduced ERP learning effects for positi... Psychophysiology journals http://www.medworm.com/rss/comments.php?id=2444464 Thu, 28 May 2009 04:00:00 +0100 2444464 http://www.medworm.com/index.php?rid=2444463&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2009.00839.x We examined whether this ability is reflected in the structure of brain regions involved in memory and the control of retrieval processes. In subjects with high recognition rates for TBF stimuli, voxel-based morphometry revealed increased gray matter (GM) volume in the left ventrolateral prefrontal cortex (VLPFC) and the right hippocampus (H). GM volume in these regions correlated positively with the TBF recognition rate. No significant differences were detected in subjects who forgot many TBF stimuli. Our findings indicate that the right H and left VLPFC are of particular relevance in releasing TBF items from inhibition caused by the F instruction. (Source: Psychophysiology) Psychophysiology journals http://www.medworm.com/rss/comments.php?id=2444463 Thu, 28 May 2009 04:00:00 +0100 2444463 http://www.medworm.com/index.php?rid=2438017&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2009.00842.x Whereas sighing appears to function as a physiological resetter, the psychological function of sighing is largely unknown. Sighing has been suggested to occur both during stress and negative emotions, such as panic and pain, and during positive emotions, such as relaxation and relief. In three experiments, sigh rate was investigated during short imposed states of stress and relief. Stress was induced by exposure to a loud noise stressor or by anticipation of it. Relief was induced by the end of the stressor or the anticipation that no stressor would follow. Breathing parameters were recorded continuously by means of the LifeShirt System. Results consistently showed that more sighing occurred during conditions of relief compared to conditions of stress. (Source: Psychophysiology) Psychophysiology journals http://www.medworm.com/rss/comments.php?id=2438017 Wed, 27 May 2009 04:00:00 +0100 2438017 http://www.medworm.com/index.php?rid=2438023&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2009.00832.x This study explored the effects of tonic blood pressure on the association between baroreceptor cardiac reflex sensitivity and cognitive performance. Sixty female participants completed a mental arithmetic task. Baroreceptor reflex sensitivity was assessed using sequence analysis. An interaction was found, indicating that the relationship between baroreceptor reflex sensitivity and cognitive performance is modulated by blood pressure levels. Reflex sensitivity was inversely associated to performance indices in the subgroup of participants with systolic blood pressure above the mean, whereas the association was positive in participants with systolic values below the mean. These results are in accordance with the findings in the field of pain perception and suggest that tonic blood pressure ... Psychophysiology journals http://www.medworm.com/rss/comments.php?id=2438023 Tue, 26 May 2009 04:00:00 +0100 2438023 http://www.medworm.com/index.php?rid=2438022&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2009.00833.x This study examined the role of these factors in moderating fear-potentiated startle (FPS) as a function of Fearless Dominance and Impulsive Antisociality[mdash]personality dimensions with links to psychopathy. University students performed a task that required them to focus on a (a) threat dimension under low working memory load, (b) threat-irrelevant dimension under low load, or (c) threat-irrelevant dimension under high load. Attentional focus, but not working memory load, moderated the relationship between Fearless Dominance and FPS. Fearless Dominance was negatively correlated with FPS only when attention was directed away from the threat. There were no significant findings for Impulsive Antisociality. Results provide evidence that reduced fear response associated with psychopathy may... Psychophysiology journals http://www.medworm.com/rss/comments.php?id=2438022 Tue, 26 May 2009 04:00:00 +0100 2438022 http://www.medworm.com/index.php?rid=2438021&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2009.00835.x Physiological reactions to noxious stimuli are often used to make inferences about pain, but few studies have thoroughly examined the intra- and interindividual relationships between them. In the present study (N=104), multilevel analyses was used to assess relations between physiological (nociceptive flexion reflex magnitude [NFR], blink reflex magnitude, skin conductance response [SCR], heart rate [HR]) and subjective reactions to electrocutaneous stimuli. All physiological reactions were significant predictors of ratings when entered alone, explaining 1% (SCR) to 29% (NFR) of the variance; but only NFR, blink, and HR were significant in a multivariate predictor model. Significant interindividual variability in slopes was found for blink and HR, but not NFR. A final trimmed model that in... Psychophysiology journals http://www.medworm.com/rss/comments.php?id=2438021 Tue, 26 May 2009 04:00:00 +0100 2438021 http://www.medworm.com/index.php?rid=2438020&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2009.00836.x Conventional eye correction methods subtract portions (propagation coefficients; Bs) of electrooculogram (EOG) voltages from the electroencephalogram (EEG). The frequency domain approach (FDA) uses different Bs for different frequencies whereas the time domain approach (TDA) uses the same Bs. To determine whether measured Bs are dependent on frequency and whether one should employ frequency-dependent methods, 20 min of EEG from eye movement (EM) and blink data (24 participants) were recorded, and Bs were calculated for eye movement ERPs of differing signal-to-noise ratios for frequency bands ranging from 0 to 40 Hz and compared. At high signal to noise, EM Bs for different frequency bands did not differ, for both vertical and horizontal EOG, at all scalp sites tested. There were small diff... Psychophysiology journals http://www.medworm.com/rss/comments.php?id=2438020 Tue, 26 May 2009 04:00:00 +0100 2438020 http://www.medworm.com/index.php?rid=2438019&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2009.00840.x Behavioral estimates of time discrimination threshold on animals might be contaminated by the conditioning procedure used and by attentional effects. To avoid such side effects, we measured time discrimination by recording the rat electroencephalographic response to small temporal variations. Freely moving rats were presented with repetitive sounds, some of them being occasionally shorter than the standard, to produce a Mismatch Negativity (MMN) which is known to primarily involve preattentive processes. The smallest difference eliciting a MMN located the discrimination threshold between 16% and 33% of the standard, without attentional confound. Being observed in several species, MMN can be used to decipher both the phylogenetic and ontogenetic evolution of time discrimination, without att... Psychophysiology journals http://www.medworm.com/rss/comments.php?id=2438019 Tue, 26 May 2009 04:00:00 +0100 2438019 http://www.medworm.com/index.php?rid=2438018&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2009.00841.x Paced breathing has been criticized for its presumed influences on autonomic and respiratory regulation, among that on respiratory resistance. It has been speculated that excessive pulmonary stretch receptor activation through high tidal volume (VT) would be the mechanism underlying such influences. However, the idea of airway dilation by paced breathing has remained untested. We analyzed inspiratory and expiratory resistance measured by forced oscillations in 26 healthy participants during baseline and two paced breathing conditions, regular pacing with instructions to alter rate only and pacing with additional instructions to alter volume randomly throughout the task. In each condition, four 3-min paced breathing trials at 8, 10.5, 13, and 18 breaths/min were administered. Despite pronou... Psychophysiology journals http://www.medworm.com/rss/comments.php?id=2438018 Tue, 26 May 2009 04:00:00 +0100 2438018 http://www.medworm.com/index.php?rid=2419850&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2009.00830.x We examined four-week test-retest reliability of corrugator electromyographic and eyeblink startle measures of negative emotion and its regulation. Both measures demonstrated similar sensitivity to the emotion manipulation, but only individual differences in corrugator modulation and regulation showed adequate reliability. Startle demonstrated diminished sensitivity to the regulation instructions across assessments and poor reliability. This suggests that corrugator represents a trait-like measure of voluntary emotion regulation, whereas startle should be used with caution for assessing individual differences. The data also suggest that corrugator and startle might index partially dissociable constructs and underscore the need to collect multiple measures of emotion. (Source: Psychophysiol... Psychophysiology journals http://www.medworm.com/rss/comments.php?id=2419850 Tue, 19 May 2009 04:00:00 +0100 2419850 http://www.medworm.com/index.php?rid=2419851&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2009.00827.x To investigate whether salient visual singletons capture attention when they appear outside the current endogenous attentional focus, we measured the N2pc component as a marker of attentional capture in a visual search task where target or nontarget singletons were presented at locations previously cued as task-relevant, or in the uncued irrelevant hemifield. In two experiments, targets were either defined by color or by a combination of color and shape. The N2pc was elicited both for attended singletons and for singletons on the uncued side, demonstrating that focused endogenous attention cannot prevent attentional capture by salient unattended visual events. However, N2pc amplitudes were larger for attended and unattended singletons that shared features with the current target, suggestin... Psychophysiology journals http://www.medworm.com/rss/comments.php?id=2419851 Fri, 15 May 2009 04:00:00 +0100 2419851 http://www.medworm.com/index.php?rid=2408957&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2009.00831.x The present study aimed to investigate the impact of facial expression, gaze interaction, and gender on attention allocation, physiological arousal, facial muscle responses, and emotional experience in simulated social interactions. Participants viewed animated virtual characters varying in terms of gender, gaze interaction, and facial expression. We recorded facial EMG, fixation duration, pupil size, and subjective experience. Subject's rapid facial reactions (RFRs) differentiated more clearly between the character's happy and angry expression in the condition of mutual eye-to-eye contact. This finding provides evidence for the idea that RFRs are not simply motor responses, but part of an emotional reaction. Eye movement data showed that fixations were longer in response to both angry and... Psychophysiology journals http://www.medworm.com/rss/comments.php?id=2408957 Fri, 15 May 2009 04:00:00 +0100 2408957 http://www.medworm.com/index.php?rid=2408960&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2009.00826.x This study assessed the validity of the Eston-Parfitt (E-P) curvilinear Ratings of Perceived Exertion (RPE) Scale and a novel marble quantity task to provide estimates of perceived exertion during cycle ergometry. Fifteen children aged 7[ndash]8 years performed a discontinuous incremental graded-exercise test, and reported exertional ratings at the end of each minute. Significant increases in physiological and perceptual data were observed with increasing work rate. The relationship between work rate and marbles was curvilinear (mean R2=.94), supporting the theoretical justification for the E-P Scale. Strong linear (R2=.93) and curvilinear (R2=.94) relationships between RPE from the E-P Scale and work rate confirmed the robustness of the E-P Scale. Valid exertional ratings may be obtained ... Psychophysiology journals http://www.medworm.com/rss/comments.php?id=2408960 Tue, 12 May 2009 04:00:00 +0100 2408960 http://www.medworm.com/index.php?rid=2408959&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2009.00828.x Interaural time and intensity disparities (ITD and IID) are the two cues to sound lateralization. "Time-only" hypothesis claims that an IID is first converted to an interaural afferent delay ([Delta]t), and is then processed by the central ITD mechanism, rendering a separate IID processor unnecessary. We tested this hypothesis by assessing the contribution of the cochlear latency effect to the psychophysical ITD/IID trading ratio. Auditory brainstem responses (ABRs) were used to measure the interaural afferent delays ([Delta]ts) that developed with a 20/sec dichotic click train used in the trading experiment. Except for small IIDs at low loudness levels, the physiological [Delta]t delay produced by an IID was significantly smaller than the ITD psychophysically traded for the same IID. We c... Psychophysiology journals http://www.medworm.com/rss/comments.php?id=2408959 Tue, 12 May 2009 04:00:00 +0100 2408959 http://www.medworm.com/index.php?rid=2408958&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2009.00829.x Positive affect was examined as a predictor of (1) cardiovascular reactivity during a sadness and an anger recall task and recovery following the protocol, (2) epinephrine (EPI) and norepinephrine (NOREPI) reactivity and level during the recall protocol, and (3) the diurnal pattern of salivary cortisol. Sample was 328 individuals. Negative affect, age, race, sex, smoking status, income, and BMI were adjusted. During sadness recall, positive affect was inversely related to systolic blood pressure (p=.007) and diastolic blood pressure (p=.049) reactivity, and unrelated to heart rate (p=.226). Positive affect was unrelated to reactivity during anger recall (ps>.19), and was unrelated to recovery at the end of the recall protocol. Positive affect was inversely related to the mean level of NORE... Psychophysiology journals http://www.medworm.com/rss/comments.php?id=2408958 Tue, 12 May 2009 04:00:00 +0100 2408958 http://www.medworm.com/index.php?rid=2335286&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2009.00825.x We investigated whether prior probability (PP) information modulates preparatory processes at a central premotor level or at a peripheral motor level. We provided parametrically graded probability information during the foreperiod of a precuing paradigm. The Contingent Negative Variation (CNV) and the Lateralized Readiness Potential (LRP) were used as indicators for premotor and motor preparation during the foreperiod, respectively. The CNV amplitude was parametrically modulated by PP. In contrast, the LRP amplitude during the foreperiod differed from baseline only when the precue was reliable. The interval between precue and LRP onset was shortened when probability information was delivered in contrast to noninformative advance information. Furthermore, a source analysis for the foreperio... Psychophysiology journals http://www.medworm.com/rss/comments.php?id=2335286 Sat, 18 Apr 2009 04:00:00 +0100 2335286 http://www.medworm.com/index.php?rid=2335291&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2009.00820.x Affective contrast refers to the tendency for stimuli to be judged as less evocative when preceded by more evocative same-valence stimuli. The authors used facial electromyographic (EMG) activity over corrugator supercilii, which is inversely related to affective valence, to determine if context influences underlying affective reactions. In Experiment 1, moderately pleasant pictures elicited less activity over corrugator supercilii when they were embedded among mildly pleasant, as opposed to extremely pleasant, pictures. In Experiment 2, moderately pleasant pictures elicited less activity over corrugator supercilii when they were embedded among mildly valent (i.e., pleasant and unpleasant), as opposed to extremely valent, pictures; moderately unpleasant pictures elicited comparable EMG act... Psychophysiology journals http://www.medworm.com/rss/comments.php?id=2335291 Tue, 14 Apr 2009 04:00:00 +0100 2335291 http://www.medworm.com/index.php?rid=2335290&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2009.00821.x Identifying overtly observable indicators of cognitive processes should provide a promising basis for a more precise tracking of the associated cognitive and neural events. In the current study we used recordings of eye movements to gain deeper insight into the time course of visuospatial problem solving as measured by the Tower of London. Single-trial, saccade-locked analyses revealed that, despite the complexity of the implemented task, gaze alternations between start and goal state followed a highly regular pattern. Consistent with the buildup of an internal representation, the first two fixations were of constant duration and unaffected by experimental variations of planning demands. Instead, planning manipulations exclusively influenced the duration of the very last fixation before pr... Psychophysiology journals http://www.medworm.com/rss/comments.php?id=2335290 Tue, 14 Apr 2009 04:00:00 +0100 2335290 http://www.medworm.com/index.php?rid=2335289&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2009.00822.x Multistable perception occurs when a single physical stimulus leads to two or more distinct percepts that spontaneously switch (reverse). Previous ERP studies have reported reversal negativities and late positive components associated with perceptual reversals. The goal of the current study was to localize the neural generators of the reversal ERP components in order to evaluate their correspondence with previous fMRI results and to better understand their functional significance. A Necker-type stimulus was presented for brief intervals while subjects indicated their perceptions. Local auto-regressive average source analyses and dipole modeling indicated that sources for the reversal negativity were located in inferior occipital-temporal cortex. Generators of the late positive component we... Psychophysiology journals http://www.medworm.com/rss/comments.php?id=2335289 Tue, 14 Apr 2009 04:00:00 +0100 2335289 http://www.medworm.com/index.php?rid=2335288&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2009.00823.x Previous research indicates that drug motivational systems are instantiated in structures that process information related to incentive, motivational drive, memorial, motor/habit, craving, and cognitive control processing. The present research tests the hypothesis that activity in such systems will be powerfully affected by the combination of drug anticipation and drug withdrawal. Event-related fMRI was used to examine activation in response to a preinfusion warning cue in two experimental sessions that manipulated withdrawal status. Significant cue-induced effects were seen in the caudate, ventral anterior nucleus of the thalamus, the insula, subcallosal gyrus, nucleus accumbens, and anterior cingulate. These results suggest that withdrawal and nicotine anticipation produce (1) different ... Psychophysiology journals http://www.medworm.com/rss/comments.php?id=2335288 Tue, 14 Apr 2009 04:00:00 +0100 2335288 http://www.medworm.com/index.php?rid=2335287&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2009.00824.x When two targets are shown in a rapid temporal stream of distractors, performance for the second target (T2) is typically reduced when presented between 200 and 500 ms after the first (T1). The present study used the steady-state visual evoked potential (ssVEP), a continuous index of electrocortical facilitation, to compare brain responses in trials with correct versus incorrect T2 responses. We found a reduction of the electrocortical response following T1 in trials with correct T2 identification. By contrast, incorrect T2 trials were characterized by enhanced electrocortical amplitude. Amplitude attenuation predictive of successful T2 report was sustained over time, suggesting a reduction of resources allocated to the distractor stream in correct trials. Across intertarget intervals, T2 ... Psychophysiology journals http://www.medworm.com/rss/comments.php?id=2335287 Tue, 14 Apr 2009 04:00:00 +0100 2335287 http://www.medworm.com/index.php?rid=2335293&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2009.00814.x We investigated whether the N2pc is unequivocally linked to distractor-suppression mechanisms, as is commonly assumed. According to the distractor-suppression account of the N2pc, no suppression, and thus no N2pc, should occur when homogeneous distractors help in selecting the target, such as when the target feature is unpredictable. Participants performed a simple detection or a finer discrimination on a singleton target, which had either a variable or a constant color. Contrary to the distractor-suppression account, an N2pc was present for both the variable and the constant conditions, and for both tasks. Additionally, target feature consistency correlated with earlier N2pc onsets relative to variable blocks. Both results indicate that the N2pc is not unequivocally linked to distractor-s... Psychophysiology journals http://www.medworm.com/rss/comments.php?id=2335293 Thu, 09 Apr 2009 04:00:00 +0100 2335293 http://www.medworm.com/index.php?rid=2335292&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2009.00818.x In between-hand choice reaction time tasks, the motor cortex involved in the required response is activated while the motor cortex involved in the non-required response is inhibited. Such an inhibition could be implemented actively between the responses defined as possible alternatives by the task instructions or, alternatively, could passively result from some kind of "reciprocal inhibition" between the two motor cortices. The present study addressed this issue. To this end, we compared the surface Laplacian transforms of electroencephalographic (EEG) waves recorded over the contralateral and ipsilateral motor cortices in between-hand and within-hand choice conditions. The dynamics of the recorded EEG activities suggest that inhibition is implemented in a feed-forward manner between the c... Psychophysiology journals http://www.medworm.com/rss/comments.php?id=2335292 Thu, 09 Apr 2009 04:00:00 +0100 2335292 http://www.medworm.com/index.php?rid=2312162&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2009.00819.x Negative priming (NP) refers to inefficient responding when previous distractors become targets. NP may reflect persisting inhibition of former distractors and/or retrieval of task-inappropriate information from the primes. In an event-related potential (ERP) study of the flanker task, NP was accompanied by reduced positivity in the P300 time range. The early portion of this effect was shared with a target-repetition condition and hence may indicate retrieval processes cued by repeated stimuli. A subsequent N400-like component was specific for NP and may reflect processing of the retrieved task-inappropriate information. In addition, NP effects on the lateralized readiness potential (LRP) matched predictions of the episodic-retrieval view. NP effects on P300, N400, and response-locked LRP ... Psychophysiology journals http://www.medworm.com/rss/comments.php?id=2312162 Wed, 08 Apr 2009 04:00:00 +0100 2312162 http://www.medworm.com/index.php?rid=2312177&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2009.00804.x Effects of exposure duration on emotional reactivity were investigated in two experiments that parametrically varied the duration of exposure to affective pictures from 25[ndash]6000 ms in the presence or absence of a visual mask. Evaluative, facial, autonomic, and cortical responses were measured. Results demonstrated that, in the absence of a visual mask (Experiment 1), emotional content modulated evaluative ratings, cortical, autonomic, and facial changes even with very brief exposures, and there was little evidence that emotional engagement increased with longer exposure. When information persistence was reduced by a visual mask (Experiment 2), differences as a function of hedonic content were absent for all measures when exposure duration was 25 ms but statistically reliable when expo... Psychophysiology journals http://www.medworm.com/rss/comments.php?id=2312177 Mon, 06 Apr 2009 04:00:00 +0100 2312177 http://www.medworm.com/index.php?rid=2312176&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2009.00808.x Two studies determined whether interval exercise reduces children's stress reactivity. For Experiment 1 children completed interval exercise (n=14) or watched TV (n=14) for 25 min. After 20 min rest children completed a speech task. Speech-induced diastolic blood pressure (DBP) reactivity was dampened in the exercise group (p (Source: Psychophysiology) Psychophysiology journals http://www.medworm.com/rss/comments.php?id=2312176 Mon, 06 Apr 2009 04:00:00 +0100 2312176 http://www.medworm.com/index.php?rid=2312174&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2009.00809.x The latency of conditioned fear after delay and trace conditioning was investigated. Some argue that delay conditioning is not dependent on awareness. In contrast, trace conditioning, where there is a gap between the conditioned stimulus (CS) and the unconditioned stimulus (US), is assumed to be dependent on awareness. In the present study, a tone CS signaled a noise US presented 1000 ms after CS onset in the delay conditioning group. In the trace conditioning group, a 200-ms tone CS was followed by an 800-ms gap prior to US presentation. Fear-potentiated startle should be seen at shorter intervals after delay conditioning compared to trace conditioning. Analyses showed increased startle at 30, 50, 100, and 150 ms after CS onset following delay conditioning compared to trace conditioning. ... Psychophysiology journals http://www.medworm.com/rss/comments.php?id=2312174 Mon, 06 Apr 2009 04:00:00 +0100 2312174 http://www.medworm.com/index.php?rid=2312172&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2009.00810.x We studied a lie detection protocol immune to countermeasures. The 4 stimulus conditions were (1 and 2) supraliminal acquaintance name primed by subliminal acquaintance name (A-A) versus subliminal nonacquaintance name (N-A) and (3 and 4) supraliminal nonacquaintance name primed by subliminal acquaintance name (A-N) versus subliminal nonacquaintance name (N-N). In Experiment 1 and replication, principal components analysis-derived event-related potential components revealed significant differences between dishonestly answered supraliminal acquaintance conditions with differing primes (A-A vs. N-A). In Experiment 2 subjects were required to lie in A-N and N-N conditions, in contrast to Experiment 1, in which subjects lied in A-A and N-A conditions. No significant effects were found. In Expe... Psychophysiology journals http://www.medworm.com/rss/comments.php?id=2312172 Mon, 06 Apr 2009 04:00:00 +0100 2312172 http://www.medworm.com/index.php?rid=2312171&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2009.00811.x This study investigated menstrual cycle phase differences in heart rate (HR) and RR interval variability (RRV) in 49 healthy, premenopausal, eumenorrheic women (age 30.2±6.2 years). HR and RRV were computed from ambulatory 24-h electrocardiogram, collected for up to 6 days, with at least 1 day each during early to midfollicular and midluteal menstrual phases. Phase effects on HR and RRV were assessed using linear mixed effects models with a random intercept to account for the correlation of observations within each subject as well as intrasubject variation. During follicular phase monitoring, women had significantly lower average HR ([minus]2.33 bpm), and higher standard deviation, the root mean squared successive difference, and high frequency (0.04[ndash]0.15 Hz) and low frequency (0.15... Psychophysiology journals http://www.medworm.com/rss/comments.php?id=2312171 Mon, 06 Apr 2009 04:00:00 +0100 2312171 http://www.medworm.com/index.php?rid=2312170&cid=s_32233_25_f&fid=32233&url=http%3A%2F%2Fdx.doi.org%2F10.1111%252Fj.1469-8986.2009.00812.x For survival, humans are continuously vigilant for signs of danger. Equally important, but less studied, is our ability to detect and respond to safety cues. The trait of positive affect may be a key component determining human variability in safety detection. Here we investigate autonomic and self-report reactivity to pictures of mutilated bodies, after reading a text about the art of mimicking injuries in the movies. Participants that scored high in positive affect trait showed attenuated autonomic reactions to the mutilation pictures. Thus, high positive affect facilitated engagement in safety cues and modulated reflexive reactions of the brain's defense system. (Source: Psychophysiology) Psychophysiology journals http://www.medworm.com/rss/comments.php?id=2312170 Mon, 06 Apr 2009 04:00:00 +0100 2312170