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Identifying the control of physically and perceptually evoked sway responses with coincident visual scene velocities and tilt of the base of support.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In this study, we have explored whether the impact of visual information on postural reactions is due to the same perceptual mechanisms that produce vection. Pitch motion of the visual field was presented at varying velocities to eight healthy subjects (29.9 +/- 2.8 years) standing quietly on a stationary base of support or receiving a 3 degrees toes-up tilt of the base of support. An infrared motion system recorded markers placed on body segments to record angular displacement of head and ankle and calculate whole body center of mass. Onset of the visual field motion and base of support movement were synchronized in all t...
Source: Experimental Brain Research - November 19, 2009 Category: Neuroscience Authors: Wang Y, Kenyon RV, Keshner EA Tags: Exp Brain Res Source Type: journals

Proprioceptive localization of the left and right hands.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The present study examined the accuracy of proprioceptive localization of the hand using two paradigms. In our proprioceptive estimation paradigm, participants judged the position of a target hand relative to visual references, or their body's midline. Placement of the target hand was active (participants pushed a robot manipulandum along a constrained path) or passive (the robot manipulandum positioned participants' target hand). In our proprioceptive-guided reaching paradigm, participants reached to the unseen location of a hand; both the left and right hands served as the target hand and the reaching hand. In both p...
Source: Experimental Brain Research - November 18, 2009 Category: Neuroscience Authors: Jones SA, Cressman EK, Henriques DY Tags: Exp Brain Res Source Type: journals

Evidence for limb-independent control of locomotor trajectory.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
After stepping in place on a rotating treadmill, individuals exhibit involuntary turning in the direction opposite treadmill rotation when stepping in place on a stationary surface without vision. This response is called podokinetic after-rotation (PKAR). It remains unclear where the control center for PKAR is located and whether separate, independent podokinetic control centers exist for each lower limb. To better understand neural mechanisms underlying locomotor trajectory adaptation, this study asked whether PKAR transfers between lower limbs. Thirteen healthy adults underwent separate 15-min sessions where one (tra...
Source: Experimental Brain Research - November 18, 2009 Category: Neuroscience Authors: McNeely ME, Earhart GM Tags: Exp Brain Res Source Type: journals

Announced reward counteracts the effects of chronic social stress on anticipatory behavior and hippocampal synaptic plasticity in rats.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In conclusion, announced short-term enriched housing has a high and long-lasting counteracting efficacy on stress-induced alterations of hippocampal synaptic plasticity. This information is important for counteracting the consequences of chronic stress in both human and captive rats. PMID: 19921157 [PubMed - as supplied by publisher] (Source: Experimental Brain Research)
Source: Experimental Brain Research - November 17, 2009 Category: Neuroscience Authors: Kamal A, Van der Harst JE, Kapteijn CM, Baars AJ, Spruijt BM, Ramakers GM Tags: Exp Brain Res Source Type: journals

Fixation disengagement enhances peripheral perceptual processing: evidence for a perceptual gap effect.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Temporal gaps between the offset of a central fixation stimulus and the onset of an eccentric target typically reduce saccade latencies (saccadic gap effect). Here, we test whether temporal gaps also affect perceptual performance in peripheral vision. In Experiment 1, subjects executed saccades to briefly presented peripheral target letters and reported letter identity afterwards. A central fixation stimulus either remained visible throughout the trial (overlap) or disappeared 200 ms before letter onset (gap). Experiment 2 tested perceptual performance without saccade execution, whereas Experiment 3 tested saccade exec...
Source: Experimental Brain Research - November 15, 2009 Category: Neuroscience Authors: Huestegge L, Koch I Tags: Exp Brain Res Source Type: journals

Kinematic analysis of the human wrist during pointing tasks.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In this work, we tested the hypothesis that intrinsic kinematic constraints such as Donders' law are adopted by the brain to solve the redundancy in pointing at targets with the wrist. Ten healthy subjects were asked to point at visual targets displayed on a monitor with the three dof of the wrist. Three-dimensional rotation vectors were derived from the orientation of the wrist acquired during the execution of the motor task and numerically fitted to a quadratic surface to test Donders' law. The thickness of the Donders' surfaces, i.e., the deviation from the best fitting surface, ranged between 1 degrees and 2 degree...
Source: Experimental Brain Research - November 15, 2009 Category: Neuroscience Authors: Campolo D, Formica D, Guglielmelli E, Keller F Tags: Exp Brain Res Source Type: journals

Response selection in dual task paradigms: observations from random generation tasks.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In conclusion, the fact that during dual task performance transient bias in one task was not associated with concurrent improvement of performance in the other task indicates that alternation of supervisory control or attentional resources from one to the other task does not mediate the observed dual task costs. Resources of the central executive are not re-allocated or 'switched' from one to the other task. Dual task costs may result from mechanisms effective within each trial such as the demands of response selection. PMID: 19915828 [PubMed - as supplied by publisher] (Source: Experimental Brain Research)
Source: Experimental Brain Research - November 14, 2009 Category: Neuroscience Authors: Dirnberger G, Jahanshahi M Tags: Exp Brain Res Source Type: journals

Editorial: Special Issue Neurovision.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
PMID: 19908034 [PubMed - as supplied by publisher] (Source: Experimental Brain Research)
Source: Experimental Brain Research - November 12, 2009 Category: Neuroscience Authors: Eysel UT, Hoffmann KP Tags: Exp Brain Res Source Type: journals

Memory-guided saccade processing in visual form agnosia (patient DF).Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
According to Milner and Goodale's model (The visual brain in action, Oxford University Press, Oxford, 2006) areas in the ventral visual stream mediate visual perception and off-line actions, whilst regions in the dorsal visual stream mediate the on-line visual control of action. Strong evidence for this model comes from a patient (DF), who suffers from visual form agnosia after bilateral damage to the ventro-lateral occipital region, sparing V1. It has been reported that she is normal in immediate reaching and grasping, yet severely impaired when asked to perform delayed actions. Here we investigated whether this disso...
Source: Experimental Brain Research - November 11, 2009 Category: Neuroscience Authors: Rossit S, Szymanek L, Butler SH, Harvey M Tags: Exp Brain Res Source Type: journals

Fitts's Law violation and motor imagery: are imagined movements truthful or lawful?Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Fitts's Law for the timing of targeted movements states that, when target width is held constant, movement time (MT) will increase as the travelled distance increases. Even imagined movements, mentally simulated actions without actual actions, obey Fitts's Law. Recently, a violation of Fitts's Law has been reported; when targets occur in a structured array, MT to the farthest target is shorter than that predicted by Fitts's Law. We conducted two experiments to determine if the violation also occurs for imagined movements. Results showed a close correspondence between real and imaginary MTs across target locations, incl...
Source: Experimental Brain Research - November 11, 2009 Category: Neuroscience Authors: Radulescu PV, Adam JJ, Fischer MH, Pratt J Tags: Exp Brain Res Source Type: journals

Striatal action-learning based on dopamine concentration.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The reinforcement learning hypothesis of dopamine function predicts that dopamine acts as a teaching signal by governing synaptic plasticity in the striatum. Induced changes in synaptic strength enable the cortico-striatal network to learn a mapping between situations and actions that lead to a reward. A review of the relevant neurophysiology of dopamine function in the cortico-striatal network and the machine reinforcement learning hypothesis reveals an apparent mismatch with recent electrophysiological studies. It was found that in addition to the well-described reward-related responses, a subpopulation of dopamine n...
Source: Experimental Brain Research - November 11, 2009 Category: Neuroscience Authors: Morris G, Schmidt R, Bergman H Tags: Exp Brain Res Source Type: journals

The trajectory of adaptation to the visuo-motor transformation of virtual and real sliding levers.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
We studied adaptation to the visuo-motor transformation of a virtual and a real two-sided sliding lever. In a previous study (Sülzenbrück and Heuer in Exp Brain Res 195:153-165, 2009) we had found essentially no differences. However, adaptation had been restricted to a simplified symmetry approximation of the transformation. In the present study practice conditions were designed to facilitate adaptation (e.g., terminal rather than continuous visual feedback). In visual open-loop tests, differences between the effects of practice with a virtual and a real lever were found for curvature of hand movements, where...
Source: Experimental Brain Research - November 10, 2009 Category: Neuroscience Authors: Sülzenbrück S, Heuer H Tags: Exp Brain Res Source Type: journals

Effects of lower limb amputation on the mental rotation of feet.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
What happens to the mental representation of our body when the actual anatomy of our body changes? We asked 18 able-bodied controls, 18 patients with a lower limb amputation and a patient with rotationplasty to perform a laterality judgment task. They were shown illustrations of feet in different orientations which they had to classify as left or right limb. This laterality recognition task, originally introduced by Parsons in Cognit Psychol 19:178-241, (1987), is known to elicit implicit mental rotation of the subject's own body part. However, it can also be solved by mental transformation of the visual stimuli. Despi...
Source: Experimental Brain Research - November 10, 2009 Category: Neuroscience Authors: Curtze C, Otten B, Postema K Tags: Exp Brain Res Source Type: journals

Contribution of GABA(C) receptors to inhibition in the rodent accessory optic system.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The medial terminal nucleus (MTN) of the mammalian accessory optic system controls vertical compensatory eye movements. It consists of two neuronal populations which respond best either to upward or to downward visual image shifts. The two cell classes are located spatially separate in the dorsal or in the ventral subdivision of the MTN, respectively. Pronounced GABAergic pathways have been described to exist between neurons in the two MTN subdivisions indicating that inhibitory interactions play a significant role for the generation of MTN cell response properties. Yet, the types of GABA receptors which mediate these ...
Source: Experimental Brain Research - November 10, 2009 Category: Neuroscience Authors: Schlicker K, Schmidt M Tags: Exp Brain Res Source Type: journals

Control of aperture closure initiation during reach-to-grasp movements under manipulations of visual feedback and trunk involvement in Parkinson's disease.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The present project was aimed at investigating how two distinct and important difficulties (coordination difficulty and pronounced dependency on visual feedback) in Parkinson's disease (PD) affect each other for the coordination between hand transport toward an object and the initiation of finger closure during reach-to-grasp movement. Subjects with PD and age-matched healthy subjects made reach-to-grasp movements to a dowel under conditions in which the target object and/or the hand were either visible or not visible. The involvement of the trunk in task performance was manipulated by positioning the target object wit...
Source: Experimental Brain Research - November 10, 2009 Category: Neuroscience Authors: Rand MK, Lemay M, Squire LM, Shimansky YP, Stelmach GE Tags: Exp Brain Res Source Type: journals

Differential rates of consolidation of conceptual and stimulus learning following training on an auditory skill.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Training-induced improvements on perceptual skills can be attributed to at least two learning types: learning of general aspects of the trained condition (conceptual learning) and learning of specific feature values of the stimulus used in training (stimulus learning). Here we asked whether conceptual and stimulus learning on interaural time difference (ITD) discrimination emerge along different time courses. Conceptual learning was clearly evident 10 h after training, when performance on a target ITD condition was equivalent following training on that condition or on a non-target condition differing only in the stimul...
Source: Experimental Brain Research - November 10, 2009 Category: Neuroscience Authors: Ortiz JA, Wright BA Tags: Exp Brain Res Source Type: journals

Bilateral parietal cortex function during motor imagery.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The aim of this study was to investigate the involvement of the parietal cortex during motor imagery (MI). In experiment one, participants imagined a sequence of upper limb movements during FMRI scanning. Statistical parametric mapping revealed a network of activation consistent with previous MI research, including activation in right and left inferior and superior parietal cortex. In experiment two, participants imagined a sequence of upper limb movements while real or sham single-pulse TMS was delivered over the scalp area corresponding to each individual's left or right superior parietal cortex. At the end of each t...
Source: Experimental Brain Research - November 6, 2009 Category: Neuroscience Authors: Fleming MK, Stinear CM, Byblow WD Tags: Exp Brain Res Source Type: journals

Placing order in space: the SNARC effect in serial learning.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
This study tests the hypothesis of an oriented spatial representation as the privileged way of mentally organizing serial information, by looking for stimulus-response compatibility effects in the processing of a newly acquired arbitrary sequence. Here we report an association between ordinal position of the items and spatial response preference for both order-relevant and order-irrelevant tasks. These results suggest that any ordered information, even when order is not intrinsically relevant to it, is spontaneously mapped in the representational space. This spatial representation is likely to acquire a left-to-right orien...
Source: Experimental Brain Research - November 4, 2009 Category: Neuroscience Authors: Previtali P, de Hevia MD, Girelli L Tags: Exp Brain Res Source Type: journals

Collinear facilitation is independent of receptive-field expansion at low contrast.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Modulation of single-cell responses by compound stimuli (target plus flankers) extending outside the cell's receptive field (RF) may represent an early neural mechanism for encoding objects in visual space, enhancing their perceptual saliency. The spatial extent of contextual modulation is wide. The size of the RF is known to be dynamically variable. It has been suggested that RF expansion when target contrast decreases is the real cause of effects attributed to modulation by flankers. This is not the case. We directly compared, in the same cells, the extent of RF size changes when stimulus contrast decreased with that...
Source: Experimental Brain Research - November 4, 2009 Category: Neuroscience Authors: Kasamatsu T, Miller R, Zhu Z, Chang M, Ishida Y Tags: Exp Brain Res Source Type: journals

Postnatal exposure to MK801 induces selective changes in GAD67 or parvalbumin.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Brain injury during the last trimester to the first 1-4 years in humans is now thought to trigger an array of intellectual and emotional problems later in life, including disorders such as schizophrenia. In adult schizophrenic brains, there is a specific loss of neurons that co-express glutamic acid decarboxylase-parvalbumin (GAD67-PV). Loss of this phenotype is thought to occur in mature animals previously exposed to N-methyl-D: -aspartate receptor (NMDAR) antagonists during late gestation or at postnatal day 7 (P7). However, in similarly treated animals, we have previously shown that GAD67 and PV are unaltered in the...
Source: Experimental Brain Research - November 3, 2009 Category: Neuroscience Authors: Turner CP, Debenedetto D, Ware E, Stowe R, Lee A, Swanson J, Walburg C, Lambert A, Lyle M, Desai P, Liu C Tags: Exp Brain Res Source Type: journals

Visuomotor adaptive improvement and aftereffects are impaired differentially following cerebellar lesions in SCA and PICA territory.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The aim of the present study was to elucidate the contribution of the superior and posterior inferior cerebellum to adaptive improvement and aftereffects in a visuomotor adaptation task. Nine patients with ischemic lesions within the territory of the posterior inferior cerebellar artery (PICA), six patients with ischemic lesions within the territory of the superior cerebellar artery (SCA) and 17 age-matched controls participated. All subjects performed center-out reaching movements under 60 degrees rotation of visual feedback. For the assessment of aftereffects, we tested retention of adaptation and de-adaptation under...
Source: Experimental Brain Research - November 3, 2009 Category: Neuroscience Authors: Werner S, Bock O, Gizewski ER, Schoch B, Timmann D Tags: Exp Brain Res Source Type: journals

Age-related differences in visual sampling requirements during adaptive locomotion.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
This study investigates if there are age- and falls-risk related differences in the length of time individuals need following fixation of a stepping target in order to step accurately onto it. This aim was achieved by manipulating the timing and location of stepping target presentation and comparing the effects on stepping performance between young adults, older adults characterised as having a low risk of falling and older adults characterised as having increased risk of falling (N = 10 in each group). Eye and lower limb kinematics were recorded using an eye tracker interfaced with a 3D motion analysis system. Temporal an...
Source: Experimental Brain Research - October 31, 2009 Category: Neuroscience Authors: Chapman GJ, Hollands MA Tags: Exp Brain Res Source Type: journals

Visuomotor mental rotation: the reaction time advantage for anti-pointing is not influenced by perceptual experience with the cardinal axes.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In the visuomotor mental rotation (VMR) paradigm, participants execute a center-out reaching movement to a location that deviates from a visual cue by a predetermined instruction angle. Previous work has demonstrated a linear increase in reaction time (RT) as a function of the amplitude of the instruction angle (Georgopoulos and Massey in Exp Brain Res 65:361-370, 1987). In contrast, we recently reported a RT advantage for an instruction angle of 180 degrees relative to a 90 degrees angle (Neely and Heath in Neurosci Lett 463:194-198, 2009). It is possible, however, that perceptual expertise with the cardinal axes, whi...
Source: Experimental Brain Research - October 31, 2009 Category: Neuroscience Authors: Neely KA, Heath M Tags: Exp Brain Res Source Type: journals

Evidence for the predictive remapping of visual attention.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
When attending an object in visual space, perception of the object remains stable despite frequent eye movements. It is assumed that visual stability is due to the process of remapping, in which retinotopically organized maps are updated to compensate for the retinal shifts caused by eye movements. Remapping is predictive when it starts before the actual eye movement. Until now, most evidence for predictive remapping has been obtained in single cell studies involving monkeys. Here, we report that predictive remapping affects visual attention prior to an eye movement. Immediately following a saccade, we show that attent...
Source: Experimental Brain Research - October 31, 2009 Category: Neuroscience Authors: Mathôt S, Theeuwes J Tags: Exp Brain Res Source Type: journals

Extrapolation of vertical target motion through a brief visual occlusion.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
It is known that arbitrary target accelerations along the horizontal generally are extrapolated much less accurately than target speed through a visual occlusion. The extent to which vertical accelerations can be extrapolated through an occlusion is much less understood. Here, we presented a virtual target rapidly descending on a blank screen with different motion laws. The target accelerated under gravity (1g), decelerated under reversed gravity (-1g), or moved at constant speed (0g). Probability of each type of acceleration differed across experiments: one acceleration at a time, or two to three different acceleratio...
Source: Experimental Brain Research - October 31, 2009 Category: Neuroscience Authors: Zago M, Iosa M, Maffei V, Lacquaniti F Tags: Exp Brain Res Source Type: journals

Properties of glutamatergic synapses in immature layer Vb pyramidal neurons: coupling of pre- and postsynaptic maturational states.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Following initial contact formation, glutamatergic synapses in cortical neurons undergo pronounced functional maturation. These maturational events, occurring both pre- and postsynaptically, have been well described in the developing hippocampus. In this paper, we characterized glutamatergic synapses in immature layer Vb pyramidal neurons of the mouse somatosensory cortex during early postnatal development. At postnatal day 7, a significant subpopulation of glutamatergic synapses exhibited a low release probability that was accompanied by strong paired-pulse facilitation of AMPA EPSCs (paired-pulse ratio >/= 2). Inc...
Source: Experimental Brain Research - October 28, 2009 Category: Neuroscience Authors: Walz C, Elßner-Beyer B, Schubert D, Gottmann K Tags: Exp Brain Res Source Type: journals

Incarnation and animation: physical versus representational deficits of body integrity.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Two apparently disparate phenomena of defective body integrity are reviewed. The first concerns dysmelia, characterized by the congenital absence or deformation of limbs, and the focus of the review is on phantom sensations of people with this kind of physical integrity disorder. The second phenomenon consists of non-psychotic individuals' desire to have a healthy limb amputated, which is interpreted as a mismatch between the physical integrity of a particular limb and its representation in multimodal cortical areas of the brain. We outlined commonalities and differences between the two conditions and note the absence,...
Source: Experimental Brain Research - October 25, 2009 Category: Neuroscience Authors: Hilti LM, Brugger P Tags: Exp Brain Res Source Type: journals

Gating of vibrotactile detection during visually guided bimanual reaches.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
It is far more difficult to detect a small tactile stimulation on a finger that is moving compared to when it is static. This suppression of tactile information during motion, known as tactile gating, has been examined in some detail during single-joint movements. However, the existence and time course of this gating has yet to be examined during visually guided multi-joint reaches, where sensory feedback may be paramount. The current study demonstrated that neurologically intact humans are unable to detect a small vibratory stimulus on one of their index fingers during a bimanual reach toward visual targets. By parame...
Source: Experimental Brain Research - October 23, 2009 Category: Neuroscience Authors: Buckingham G, Carey DP, Colino FL, Degrosbois J, Binsted G Tags: Exp Brain Res Source Type: journals

Influence of accuracy constraints on bimanual coordination during a goal-directed task in children with hemiplegic cerebral palsy.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Previously we found that children with hemiplegic cerebral palsy (CP) have impaired bimanual coordination compared to typically developing children during a functional drawer-opening task. However, performance of the task under time constraints (fast-as-possible) facilitated better bimanual coordination for these children. Accuracy is another important task constraint that could influence the coordination of the two hands during such tasks. The effect of accuracy constraints on bimanual coordination in children with hemiplegic CP is not well understood. In the present study, children were asked to reach forward and ope...
Source: Experimental Brain Research - October 23, 2009 Category: Neuroscience Authors: Hung YC, Charles J, Gordon AM Tags: Exp Brain Res Source Type: journals

Adaptation to motor-visual and motor-auditory temporal lags transfer across modalities.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Previous research has shown that the timing of a sensor-motor event is recalibrated after a brief exposure to a delayed feedback of a voluntary action (Stetson et al. 2006). Here, we examined whether it is the sensory or motor event that is shifted in time. We compared lag adaption for action-feedback in visuo-motor pairs and audio-motor pairs using an adaptation-test paradigm. Participants were exposed to a constant lag (50 or 150 ms) between their voluntary action (finger tap) and its sensory feedback (flash or tone pip) during an adaptation period (~3 min). Immediately after that, they performed a temporal order jud...
Source: Experimental Brain Research - October 23, 2009 Category: Neuroscience Authors: Sugano Y, Keetels M, Vroomen J Tags: Exp Brain Res Source Type: journals

The effects of multisensory targets on saccadic trajectory deviations: eliminating age differences.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The present study had two aims. First, to determine if bimodal audio-visual targets allow for greater inhibition of visual distractors, which in turn may lead to greater saccadic trajectory deviations away from those distractors. Second, to determine if bimodal targets can reduce age differences in the ability to generate deviations away, as older adults tend to benefit more from multisensory integration than younger adults. The results show that bimodal targets produced larger deviations away than unimodal targets, but only when the distractor preceded the target, and this effect was comparable across age groups. Furt...
Source: Experimental Brain Research - October 23, 2009 Category: Neuroscience Authors: Campbell KL, Al-Aidroos N, Fatt R, Pratt J, Hasher L Tags: Exp Brain Res Source Type: journals

Manual obstacle avoidance takes into account visual uncertainty, motor noise, and biomechanical costs.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Moving around obstacles requires balancing the need to avoid collisions with the need to minimize biomechanical costs. We investigated this tradeoff by studying the effects of visual uncertainty, motor noise, and practice on clearance over obstacles in a manual positioning task. Participants moved a manipulandum back and forth over a stationary obstacle. We varied visual uncertainty by placing the obstacle at different heights relative to participants' eyes, and we varied motor noise by having participants hold the object to be moved at different positions relative to the range of motion of the arm joints. Clearance wa...
Source: Experimental Brain Research - October 23, 2009 Category: Neuroscience Authors: Cohen RG, Biddle JC, Rosenbaum DA Tags: Exp Brain Res Source Type: journals

Adaptive and phase transition behavior in performance of discrete multi-articular actions by degenerate neurobiological systems.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The identification of attractors is one of the key tasks in studies of neurobiological coordination from a dynamical systems perspective, with a considerable body of literature resulting from this task. However, with regards to typical movement models investigated, the overwhelming majority of actions studied previously belong to the class of continuous, rhythmical movements. In contrast, very few studies have investigated coordination of discrete movements, particularly multi-articular discrete movements. In the present study, we investigated phase transition behavior in a basketball throwing task where participants w...
Source: Experimental Brain Research - October 23, 2009 Category: Neuroscience Authors: Rein R, Davids K, Button C Tags: Exp Brain Res Source Type: journals

How and when auditory action effects impair motor performance.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Music performance is characterized by complex cross-modal interactions, offering a remarkable window into training-induced long-term plasticity and multimodal integration processes. Previous research with pianists has shown that playing a musical score is affected by the concurrent presentation of musical tones. We investigated the nature of this audio-motor coupling by evaluating how congruent and incongruent cross-modal auditory cues affect motor performance at different time intervals. We found facilitation if a congruent sound preceded motor planning with a large Stimulus Onset Asynchrony (SOA -300 and -200 ms), wh...
Source: Experimental Brain Research - October 21, 2009 Category: Neuroscience Authors: D'Ausilio A, Brunetti R, Delogu F, Santonico C, Belardinelli MO Tags: Exp Brain Res Source Type: journals

Effects of DBS on precision grip abnormalities in essential tremor.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Deep brain stimulation (DBS) of the ventrolateral thalamus is a highly effective procedure for the treatment of essential tremor (ET). The regularity of repetitive, self-paced finger tapping is known to be abnormal in patients with ET and improved following DBS. However, the more complex timing that underlies force development in the hands in ET and after DBS has not been evaluated. In this pilot study, we assessed precision grip performance in seven ET subjects before and after 5 months of DBS. Ten healthy controls were also studied. ET subjects showed a significant increase in preload duration (235 +/- 145 vs. 82 +/-...
Source: Experimental Brain Research - October 20, 2009 Category: Neuroscience Authors: Stani TM, Burchiel KJ, Hart MJ, Lenar DP, Anderson VC Tags: Exp Brain Res Source Type: journals

Modulation of proprioceptive inflow when initiating a step influences postural adjustments.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
A synergistic inclination of the whole body towards the supporting leg is required when producing a stepping movement. It serves to shift the centre of mass towards the stance foot. While the importance of sensory information in the setting of this postural adjustment is undisputed, it is currently unknown the extent to which proprioceptive afferences (Ia) give rise to postural regulation during stepping movement when the availability of other sensory information relying on static linear acceleration (gravity) is no longer sensed in microgravity. We tested this possibility asking subjects to step forward with their eye...
Source: Experimental Brain Research - October 15, 2009 Category: Neuroscience Authors: Ruget H, Blouin J, Coyle T, Mouchnino L Tags: Exp Brain Res Source Type: journals

Control of dynamic stability during adaptation to gait termination on a slippery surface.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
An unexpected slip during gait termination results in a generalised slip response designed to regain stability and prevent a fall. With knowledge of and experience with a slippery surface, locomotor behaviour adapts to proactively diminish the effect of the slip and improve the reactive control during the slip. Our purpose was to examine the organisation of the adaptation to a slippery surface during gait termination. After receiving an unexpected slip during gait termination, participants (N = 8) experienced cued gait termination trials in which they were given knowledge of the surface characteristics (i.e., slippery ...
Source: Experimental Brain Research - October 15, 2009 Category: Neuroscience Authors: Oates AR, Frank JS, Patla AE Tags: Exp Brain Res Source Type: journals

Perceiving emotion in crowds: the role of dynamic body postures on the perception of emotion in crowded scenes.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Although the perception of emotion in individuals is an important social skill, very little is known about how emotion is determined from a crowd of individuals. We investigated the perception of emotion in scenes of crowds populated by dynamic characters each expressing an emotion. Facial expressions were masked in these characters and emotion was conveyed using body motion and posture only. We systematically varied the proportion of characters in each scene depicting one of two emotions and participants were required to categorise the overall emotion of the crowd. In Experiment 1, we found that the perception of emot...
Source: Experimental Brain Research - October 14, 2009 Category: Neuroscience Authors: McHugh JE, McDonnell R, O'Sullivan C, Newell FN Tags: Exp Brain Res Source Type: journals

Detection of visual feedback delay in active and passive self-body movements.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Temporal congruency between the efference copy of a motor command and the reafferent sensory feedback is crucial for identifying self-generated body movements. We investigated how temporal discrepancy between the efference copy and visual feedback affects the self-body movement recognition process. Subjects experienced active and passive hand movements under conditions of delayed visual feedback (118-352 ms) and judged whether observed hand movements were delayed with respect to the felt movement. The results showed that the discrimination threshold of visual feedback delay (50% detection rate) was not significantly di...
Source: Experimental Brain Research - October 14, 2009 Category: Neuroscience Authors: Shimada S, Qi Y, Hiraki K Tags: Exp Brain Res Source Type: journals

Real-time error detection but not error correction drives automatic visuomotor adaptation.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
We investigated the role of visual feedback of task performance in visuomotor adaptation. Participants produced novel two degrees of freedom movements (elbow flexion-extension, forearm pronation-supination) to move a cursor towards visual targets. Following trials with no rotation, participants were exposed to a 60 degrees visuomotor rotation, before returning to the non-rotated condition. A colour cue on each trial permitted identification of the rotated/non-rotated contexts. Participants could not see their arm but received continuous and concurrent visual feedback (CF) of a cursor representing limb position or post-...
Source: Experimental Brain Research - October 14, 2009 Category: Neuroscience Authors: Hinder MR, Riek S, Tresilian JR, de Rugy A, Carson RG Tags: Exp Brain Res Source Type: journals

Antinociception by motor cortex stimulation in the neuropathic rat: does the locus coeruleus play a role?Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
We studied whether stimulation of the primary motor cortex (M1) attenuates pain-related spinal withdrawal responses of neuropathic and healthy control rats, and whether the descending antinociceptive effect is relayed through the noradrenergic locus coeruleus (LC). The assessments of the noxious heat-evoked limb withdrawals reflecting spinal nociception and recordings of single LC units were performed in spinal nerve-ligated neuropathic and sham-operated control rats under light pentobarbital anesthesia. Electric stimulation of M1 produced equally strong spinal antinociception in neuropathic and control rats. Following...
Source: Experimental Brain Research - October 13, 2009 Category: Neuroscience Authors: Viisanen H, Pertovaara A Tags: Exp Brain Res Source Type: journals

The influence of goals on movement kinematics during imitation.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
This study took a quantitative approach to investigate movement kinematics during the imitation of goal-directed and non-goal directed movements. Motion tracking equipment was used to record the hand movements of 15 healthy participants during an imitation task involving aiming movements that varied in speed. We predicted that movement kinematics would be most similar to the observed movements in the non-goal condition, as a result of direct visuomotor mapping of the action, and least similar in the goal-directed condition because more importance would be given to the end goal. We also predicted that precues (prior informa...
Source: Experimental Brain Research - October 13, 2009 Category: Neuroscience Authors: Wild KS, Poliakoff E, Jerrison A, Gowen E Tags: Exp Brain Res Source Type: journals

The effect of ballistic thumb contractions on the excitability of the ipsilateral motor cortex.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
We investigated how ballistic contractions of the left thumb affect the excitability of the ipsilateral motor cortex using transcranial magnetic stimulation (TMS). TMS was applied at the motor hotspot for the right abductor pollicis brevis (APB) muscle. In 'self-triggered' trials, participants made targeted, isometric, contractions of the left APB. The right APB was either relaxed or maintained a tonic contraction. TMS was administered as soon as possible after electromyographic onset in the left APB. In 'control' trials, the left thumb remained quiescent and TMS was triggered by the computer. In each condition, 20-24 ...
Source: Experimental Brain Research - October 13, 2009 Category: Neuroscience Authors: Hinder MR, Schmidt MW, Garry MI, Summers JJ Tags: Exp Brain Res Source Type: journals

Motor skill learning depends on protein synthesis in the dorsal striatum after training.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Functional imaging studies in humans and electrophysiological data in animals suggest that corticostriatal circuits undergo plastic modifications during motor skill learning. In motor cortex and hippocampus circuit plasticity can be prevented by protein synthesis inhibition (PSI) which can interfere with certain forms learning. Here, the hypothesis was tested that inducing PSI in the dorsal striatum by bilateral intrastriatal injection of anisomycin (ANI) in rats interferes with learning a precision forelimb reaching task. Injecting ANI shortly after training on days 1 and 2 during 4 days of daily practice (n = 14) led...
Source: Experimental Brain Research - October 12, 2009 Category: Neuroscience Authors: Wächter T, Röhrich S, Frank A, Molina-Luna K, Pekanovic A, Hertler B, Schubring-Giese M, Luft AR Tags: Exp Brain Res Source Type: journals

Hands only illusion: multisensory integration elicits sense of ownership for body parts but not for non-corporeal objects.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The experience of body ownership can be successfully manipulated during the rubber hand illusion using synchronous multisensory stimulation. The hypothesis that multisensory integration is both a necessary and sufficient condition for body ownership is debated. We systematically varied the appearance of the object that was stimulated in synchrony or asynchrony with the participant's hand. A viewed object that was transformed in three stages from a plain wooden block to a wooden hand was compared to a realistic rubber hand. Introspective and behavioural results show that participants experience a sense of ownership only...
Source: Experimental Brain Research - October 9, 2009 Category: Neuroscience Authors: Tsakiris M, Carpenter L, James D, Fotopoulou A Tags: Exp Brain Res Source Type: journals

Irregular head movement patterns in whiplash patients during a trajectory task.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In conclusion, irregular head movements during a complex task were found in the WAD group, indicating altered central sensorimotor processing. The irregularities were found within frequency levels observable to clinicians. PMID: 19820919 [PubMed - as supplied by publisher] (Source: Experimental Brain Research)
Source: Experimental Brain Research - October 9, 2009 Category: Neuroscience Authors: Woodhouse A, Stavdahl O, Vasseljen O Tags: Exp Brain Res Source Type: journals

The effect of haptic guidance, aging, and initial skill level on motor learning of a steering task.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
This study demonstrates that training with haptic guidance can benefit long-term retention of a driving skill for young and for some old drivers. Training with haptic guidance is more useful for people with less initial skill. PMID: 19820920 [PubMed - as supplied by publisher] (Source: Experimental Brain Research)
Source: Experimental Brain Research - October 9, 2009 Category: Neuroscience Authors: Marchal-Crespo L, McHughen S, Cramer SC, Reinkensmeyer DJ Tags: Exp Brain Res Source Type: journals

Eye-hand coupling is not the cause of manual return movements when searching.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
When searching for a target with eye movements, saccades are planned and initiated while the visual information is still being processed, so that subjects often make saccades away from the target and then have to make an additional return saccade. Presumably, the cost of the additional saccades is outweighed by the advantage of short fixations. We previously showed that when the cost of passing the target was increased, by having subjects manually move a window through which they could see the visual scene, subjects still passed the target and made return movements (with their hand). When moving a window in this manner...
Source: Experimental Brain Research - October 8, 2009 Category: Neuroscience Authors: Liesker H, Brenner E, Smeets JB Tags: Exp Brain Res Source Type: journals

Static and dynamic discharge properties of vestibular-nerve afferents in the mouse are affected by core body temperature.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The goal of this study was to determine the effect of changes in core body temperature on the resting discharge rate and sensitivity of vestibular-nerve afferents. Extracellular recordings were made from vestibular-nerve afferents innervating the semicircular canals in anesthetized C57BL/6 mice maintained at a core body temperature of either 30-32 degrees C (T (31)) or 35-37 degrees C (T (36)). The resting rates of regular (CV* < 0.1) and irregular afferents (CV* > 0.1) were lower at T (31) than at T (36). Sensitivity and phase were compared for rotations ranging from 0.1 to 12 Hz by calculating coefficients of a...
Source: Experimental Brain Research - October 5, 2009 Category: Neuroscience Authors: Park HJ, Lasker DM, Minor LB Tags: Exp Brain Res Source Type: journals

Impossible is nothing: 5:3 and 4:3 multi-frequency bimanual coordination.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The present findings demonstrate that when participants are provided a Lissajous display with cursor indicating the position of the limbs and a template illustrating the desired movement pattern they can rapidly (10 min) and effectively (continuous relative phase errors and variability ~10 degrees ) tune in a difficult 5:3 bimanual coordination pattern and without additional practice re-tune their responding to an equally difficult 4:3 coordination pattern. The findings indicate the extreme difficulty associated with producing complex polyrhythms in previous experiments has been due to split attention when Lissajous fe...
Source: Experimental Brain Research - October 1, 2009 Category: Neuroscience Authors: Kovacs AJ, Buchanan JJ, Shea CH Tags: Exp Brain Res Source Type: journals