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 'Human Brain Mapping' source. Wed, 08 Feb 2012 20:43:08 +0100 http://www.medworm.com/index.php?rid=5650110&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.22044 In this study, we used functional magnetic resonance imaging (fMRI) to investigate how people perceive the actions of in‐group and out‐group members, and how their biased view in favor of own team members manifests itself in the brain. We divided participants into two teams and had them judge the relative speeds of hand actions performed by an in‐group and an out‐group member in a competitive situation. Participants judged hand actions performed by in‐group members as being faster than those of out‐group members, even when the two actions were performed at physically identical speeds. In an additional fMRI experiment, we showed that, contrary to common belief, such skewed impressions arise from a subtle bias in perception and associated brain activity rather than decision‐mak... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5650110 Wed, 01 Feb 2012 05:00:00 +0100 5650110 http://www.medworm.com/index.php?rid=5650117&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21504 AbstractPost‐lingual deafness induces a decline in the ability to process phonological sounds or evoke phonological representations. This decline is paralleled with abnormally high neural activity in the right posterior superior temporal gyrus/supramarginal gyrus (PSTG/SMG). As this neural plasticity negatively relates to cochlear implantation (CI) success, it appears important to understand its determinants. We addressed the neuro‐functional mechanisms underlying this maladaptive phenomenon using behavioral and functional magnetic resonance imaging (fMRI) data acquired in 10 normal‐hearing subjects and 10 post‐lingual deaf candidates for CI. We compared two memory tasks where subjects had to evoke phonological (speech) and environmental sound representations from visually presente... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5650117 Mon, 30 Jan 2012 05:00:00 +0100 5650117 http://www.medworm.com/index.php?rid=5650116&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21505 AbstractThe primary aim of this study was to enhance our understanding of the functional architecture of the cortico‐basal ganglia circuitry during motor task execution. Twenty right‐handed female subjects without any history of neuropsychiatric illness underwent fMRI at 3 T. The activation paradigm was a complex motor task completed with the nondominant hand. Analyses of functional connectivity strength were conducted for pairs of structures in input, intrinsic, and output segments of the circuitry. Next, connectivity strengths were correlated with results of neurocognitive testing conducted outside of the scanner, which provided information about both motor and cognitive processes. For input pathways, results indicate that SMA–striatum interactions are particularly relevant for mot... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5650116 Mon, 30 Jan 2012 05:00:00 +0100 5650116 http://www.medworm.com/index.php?rid=5650115&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21506 AbstractResearch in auditory neuroscience has largely neglected the possible effects of different listening tasks on activations of auditory cortex (AC). In the present study, we used high‐resolution fMRI to compare human AC activations with sounds presented during three auditory and one visual task. In all tasks, subjects were presented with pairs of Finnish vowels, noise bursts with pitch and Gabor patches. In the vowel pairs, one vowel was always either a prototypical /i/ or /ae/ (separately defined for each subject) or a nonprototype. In different task blocks, subjects were either required to discriminate (same/different) vowel pairs, to rate vowel “goodness” (first/second sound was a better exemplar of the vowel class), to discriminate pitch changes in the noise bursts, or to di... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5650115 Mon, 30 Jan 2012 05:00:00 +0100 5650115 http://www.medworm.com/index.php?rid=5650114&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21507 AbstractWhat is it like to be at the lower boundaries of consciousness? Disorders of consciousness such as coma, the vegetative state, and the minimally conscious state are among the most mysterious and least understood conditions of the human brain. Particularly complicated is the assessment of residual cognitive functioning and awareness for diagnostic, rehabilitative, legal, and ethical purposes. In this article, we present a novel functional magnetic resonance imaging exploration of visual cognition in a patient with a severe disorder of consciousness. This battery of tests, first developed in healthy volunteers, assesses increasingly complex transformations of visual information along a known caudal to rostral gradient from occipital to temporal cortex. In the first five levels, the b... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5650114 Mon, 30 Jan 2012 05:00:00 +0100 5650114 http://www.medworm.com/index.php?rid=5650113&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21508 AbstractThe ability to suppress and flexibly adapt motor behavior is a fundamental mechanism of cognitive control, which is impaired in traumatic brain injury (TBI). Here, we used a combination of functional magnetic resonance imaging and diffusion weighted imaging tractography to study changes in brain function and structure associated with motor switching performance in TBI. Twenty‐three young adults with moderate‐severe TBI and twenty‐six healthy controls made spatially and temporally coupled bimanual circular movements. A visual cue signaled the right hand to switch or continue its circling direction. The time to initiate the switch (switch response time) was longer and more variable in the TBI group and TBI patients exhibited a higher incidence of complete contralateral (left ha... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5650113 Mon, 30 Jan 2012 05:00:00 +0100 5650113 http://www.medworm.com/index.php?rid=5650112&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21511 This study constructs a rat brain T2‐weighted magnetic resonance imaging template including olfactory bulb and a compatible digital atlas. The atlas contains 624 carefully delineated brain structures based on the newest (2005) edition of rat brain atlas by Paxinos and Watson. An automated procedure, as an SPM toolbox, was introduced for spatially normalizing individual rat brains, conducting statistical analysis and visually localizing the results in the Atlas coordinate space. The brain template/atlas and the procedure were evaluated using functional images between rats with the right side middle cerebral artery occlusion (MCAO) and normal controls. The result shows that the brain region with significant signal decline in the MCAO rats was consistent with the occlusion position. Hum Bra... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5650112 Mon, 30 Jan 2012 05:00:00 +0100 5650112 http://www.medworm.com/index.php?rid=5650111&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21515 AbstractPosterior parahippocampal gyrus (PPHG) is strongly involved during scene recognition and spatial cognition. How PPHG electrophysiological activity could underlie these functions, and whether they share similar timing mechanisms is unknown. We addressed this question in two intracerebral experiments which revealed that PPHG neural activity dissociated an early stimulus‐driven effect (>200 and <500 ms) and a late task‐related effect (>600 and <800 ms). Strongest PPHG gamma band (50–150 Hz) activities were found early when subjects passively viewed scenes (scene selectivity effect) and lately when they had to estimate the position of an object relative to the environment (allocentric effect). Based on single trial analyses, we were able to predict when patients viewe... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5650111 Mon, 30 Jan 2012 05:00:00 +0100 5650111 http://www.medworm.com/index.php?rid=5599405&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21509 This study provides functional magnetic resonance imaging evidence for brain regions underlying the persistence of postcategorical representations of visual stimuli. In a partial report paradigm, subjects matched a cued row of a 3 × 3 array of letters (postcategorical stimuli) or false fonts (precategorical stimuli) with a subsequent triplet of stimuli. The cued row was indicated by two visual flankers presented at the onset (physical stimulus readout) or after the offset of the array (iconic memory readout). The left planum temporale showed a greater modulation of the source of readout (iconic memory vs. physical stimulus) when letters were presented compared to false fonts. This is a multimodal brain region responsible for matching incoming acoustic and visual patterns with acoustic pat... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5599405 Wed, 18 Jan 2012 02:01:10 +0100 5599405 http://www.medworm.com/index.php?rid=5599413&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21454 AbstractWater diffusion magnetic resonance imaging (dMRI) is a powerful tool for studying biological tissue microarchitectures in vivo. Recently, there has been increased effort to develop quantitative dMRI methods to probe both length scale and orientation information in diffusion media. Diffusion spectrum imaging (DSI) is one such approach that aims to resolve such information based on the three‐dimensional diffusion propagator at each voxel. However, in practice, only the orientation component of the propagator function is preserved when deriving the orientation distribution function. Here, we demonstrate how a straightforward extension of the linear spherical deconvolution (SD) model can be used to probe tissue orientation structures over a range (or “spectrum”) of length scales ... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5599413 Mon, 16 Jan 2012 05:00:00 +0100 5599413 http://www.medworm.com/index.php?rid=5599412&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21469 Conclusions: There is still an abnormal functional connectivity of several brain networks in remission after the first episode of schizophrenia. The effect of different treatment modalities on brain connectivity, together with temporal dynamics of this functional abnormality should be the objective of further studies to assess its potential as a marker of disease stabilization. Hum Brain Mapp, 2012. © 2012 Wiley Periodicals, Inc. (Source: Human Brain Mapping) Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5599412 Mon, 16 Jan 2012 05:00:00 +0100 5599412 http://www.medworm.com/index.php?rid=5599411&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21494 AbstractPrevious studies suggest the importance of medial temporal lobe, areas of parietal cortex, and retrosplenial cortex in human spatial navigation, though the exact role of these structures in representing the relations of elements within a spatial layout (“allocentric” representation) remains unresolved. Hippocampal involvement, in particular, during memory processing is affected by whether a previously formed representation is employed in a novel fashion (“flexible” usage) or in a manner comparable with how it was encoded originally (“rigid” usage). To address whether brain systems are differentially involved during flexible vs. rigid utilization of a pre‐existing allocentric representation, subjects encoded the position of six different target buildings relative to a ... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5599411 Mon, 16 Jan 2012 05:00:00 +0100 5599411 http://www.medworm.com/index.php?rid=5599410&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21497 AbstractPattern recognition approaches to the analysis of neuroimaging data have brought new applications such as the classification of patients and healthy controls within reach. In our view, the reliance on expensive neuroimaging techniques which are not well tolerated by many patient groups and the inability of most current biomarker algorithms to accommodate information about prior class frequencies (such as a disorder's prevalence in the general population) are key factors limiting practical application. To overcome both limitations, we propose a probabilistic pattern recognition approach based on cheap and easy‐to‐use multi‐channel near‐infrared spectroscopy (fNIRS) measurements. We show the validity of our method by applying it to data from healthy controls (n = 14) enabling... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5599410 Mon, 16 Jan 2012 05:00:00 +0100 5599410 http://www.medworm.com/index.php?rid=5599409&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21498 In this study we investigated if single‐trial‐based brain activity was sufficient to distinguish abstract (e.g., mercy) versus concrete (e.g., barn) concept representations. Multiple neuroimaging studies have identified differences in the processing of abstract versus concrete concepts based on the averaged activity across time by using univariate methods. In this study we used multi‐voxel pattern analysis to decode functional magnetic resonance imaging (fMRI) data when participants perform a semantic similarity judgment task on triplets of either abstract or concrete words with similar meanings. Classifiers were trained to identify individual trials as concrete or abstract. Cross‐validated accuracies for classifying trials as abstract or concrete were significantly above chance (P... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5599409 Mon, 16 Jan 2012 05:00:00 +0100 5599409 http://www.medworm.com/index.php?rid=5599408&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21500 AbstractFine surface texture is best discriminated by touch, in contrast to macro geometric features like shape. We used functional magnetic resonance imaging and a delayed match‐to‐sample task to investigate the neural substrate for working memory of tactile surface texture. Blindfolded right‐handed males encoded the texture or location of up to four sandpaper stimuli using the dominant or non‐dominant hand. They maintained the information for 10–12 s and then answered whether a probe stimulus matched the memory array. Analyses of variance with the factors Hand, Task, and Load were performed on the estimated percent signal change for the encoding and delay phase. During encoding, contralateral effects of Hand were found in sensorimotor regions, whereas Load effects were observed... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5599408 Mon, 16 Jan 2012 05:00:00 +0100 5599408 http://www.medworm.com/index.php?rid=5599407&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21465 AbstractCharacterizing the neural substrate of reasoning has been investigated with regularity over the last 10 years or so while relying on measures that come primarily from positron emission tomography and functional magnetic resonance imaging. To some extent, these techniques—as well as those from electroencephalography—have shown that time course is equally worthwhile for revealing the way reasoning processes work in the brain. In this work, we employ magnetoencephalography while investigating Modus Ponens (If P then Q; P//Therefore, Q) in order to simultaneously derive time course and the source of this fundamental logical inference. The present results show that conditional reasoning involves several successive cognitive processes, each of which engages a distinct cerebral networ... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5599407 Mon, 16 Jan 2012 05:00:00 +0100 5599407 http://www.medworm.com/index.php?rid=5599406&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21495 We present here a generalized BOLD signal model that reduces under appropriate conditions to previous models derived for hypercapnia or hyperoxia alone, and is suitable for use during hybrid breathing manipulations including simultaneous hypercapnia and hyperoxia. This new approach yields robust and accurate M maps, in turn allowing more reliable estimation of CMRO2 changes evoked during a visual task. The generalized model is valid for arbitrary flow changes during hyperoxia, thus benefiting from the larger total oxygenation changes produced by increased blood O2 content from hyperoxia combined with increases in flow from hypercapnia. This in turn reduces the degree of extrapolation required to estimate M. The new procedure yielded M estimates that were generally higher (7.6 ± 2.6) than ... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5599406 Mon, 16 Jan 2012 05:00:00 +0100 5599406 http://www.medworm.com/index.php?rid=5599414&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21408 AbstractViewing other's pain inhibits the excitability of the motor cortex and also modulates the neural activity elicited by a concomitantly delivered nociceptive somatosensory stimulus. As the neural activity elicited by a transient nociceptive stimulus largely reflects non nociceptive‐specific, multimodal neural processes, here we tested, for the first time, whether the observation of other's pain preferentially affects the brain responses elicited by nociceptive stimulation, or instead similarly modulates those elicited by stimuli belonging to a different sensory modality. Using 58‐channel electroencephalography (EEG), we recorded the cortical responses elicited by laser and auditory stimulation during the observation of videoclips showing either noxious or non‐noxious stimulatio... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5599414 Tue, 10 Jan 2012 05:00:00 +0100 5599414 http://www.medworm.com/index.php?rid=5562012&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21439 Conclusions. Our results indicate that in the early course of depression, depressive state is associated with increased left prefrontal activation during the attempt to recollect source information suggesting an increased need for executive control during recollection in MDD. In this sample of first‐episode MDD patients we found no evidence for hippocampal dysfunction. Hum Brain Mapp, 2012. © 2012 Wiley Periodicals, Inc. (Source: Human Brain Mapping) Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5562012 Tue, 03 Jan 2012 05:00:00 +0100 5562012 http://www.medworm.com/index.php?rid=5562011&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21442 AbstractWe studied online coupling between a reader's voice and a listener's cortical activity using a novel, ecologically valid continuous listening paradigm. Whole‐scalp magnetoencephalographic (MEG) signals were recorded from 10 right‐handed, native French‐speaking listeners in four conditions: a female (Exp1f) and a male (Exp1m) reading the same text in French; a male reading a text in Finnish (Exp 2), a language incomprehensible for the subjects, and a male humming Exp1 text (Exp 3). The fundamental frequency (f0) of the reader's voice was recorded with an accelerometer attached to the throat, and coherence was computed between f0 time‐course and listener's MEG. Similar levels of right‐hemisphere‐predominant coherence were found at ˜0.5 Hz in Exps 1–3. Dynamic imaging o... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5562011 Tue, 03 Jan 2012 05:00:00 +0100 5562011 http://www.medworm.com/index.php?rid=5562010&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21490 Conclusion: These results suggest a relationship between anosognosia and hemispheric asymmetry in schizophrenia, supporting previous volume‐based MRI studies in schizophrenia that found a relationship between illness unawareness and reduced right hemisphere gray matter volume. Functional imaging studies are required to examine the neural mechanisms contributing to these structural observations. Hum Brain Mapp , 2012. © 2012 Wiley Periodicals, Inc. (Source: Human Brain Mapping) Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5562010 Sun, 01 Jan 2012 05:00:00 +0100 5562010 http://www.medworm.com/index.php?rid=5488533&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21488 AbstractDuring task switching, if we occasionally encounter stimuli that cue more than one task (i.e., bivalent stimuli), response slowing is observed on all univalent trials within that block, even when no features overlap with the bivalent stimuli. This observation is known as the bivalency effect. Previous fMRI work (Woodward et al., 2008) clearly suggests a role for the dorsal anterior cingulate cortex (dACC) in the bivalency effect, but the time course remains uncertain. Here, we present the first high‐temporal resolution account for the bivalency effect using stimulus‐locked event‐related potentials. Participants alternated among three simple tasks in six experimental blocks, with bivalent stimuli appearing occasionally in bivalent blocks (blocks 2, 4, and 6). The increased rea... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5488533 Thu, 08 Dec 2011 05:00:00 +0100 5488533 http://www.medworm.com/index.php?rid=5488532&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21493 AbstractCerebral activations involved in actual writing of a new story and the associated correlates with creative performance are still unexplored. To investigate the different aspects of the creative writing process, we used functional magnetic resonance imaging while 28 healthy participants performed a new paradigm related to creative writing: “brainstorming” (planning a story) and “creative writing” (writing a new and creative continuation of a given literary text), as well as an additional control paradigm of “reading” and “copying.” Individual verbal creativity was assessed with a verbal creativity test and creative performance with a qualitative rating of the creative products. “brainstorming” engaged cognitive, linguistic, and creative brain functions mainly rep... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5488532 Thu, 08 Dec 2011 05:00:00 +0100 5488532 http://www.medworm.com/index.php?rid=5488531&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21502 AbstractPremenstrual increases in negative mood are thought to arise from changes in gonadal hormone levels, presumably by influencing mood regulation and stress sensitivity. The amygdala plays a major role in this context, and animal studies suggest that gonadal hormones influence its morphology. Here, we investigated whether amygdala morphology changes over the menstrual cycle and whether this change explains differences in stress sensitivity. Twenty‐eight young healthy women were investigated once during the premenstrual phase and once during the late follicular phase. T1‐weighted anatomical images of the brain were acquired using magnetic resonance imaging and analyzed with optimized voxel‐based morphometry. To measure mood regulation and stress sensitivity, negative affect was a... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5488531 Thu, 08 Dec 2011 05:00:00 +0100 5488531 http://www.medworm.com/index.php?rid=5470286&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21354 In conclusion, statistical associations were found between parental overprotection during childhood and adolescence and adulthood HPA axis hypoactivity, and between HPA axis hypoactivity and hippocampal GM volume reduction in healthy young adults, but no significant relationship was observed between any PBI scores and adulthood hippocampal GM volume. Hum Brain Mapp, 2011. © 2011 Wiley Periodicals, Inc. (Source: Human Brain Mapping) Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5470286 Sat, 03 Dec 2011 05:00:00 +0100 5470286 http://www.medworm.com/index.php?rid=5470285&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21468 AbstractThe human brain undergoes structural changes in children entering puberty, while simultaneously children increase in height. It is not known if brain changes are under genetic control, and whether they are related to genetic factors influencing the amount of overall increase in height. Twins underwent magnetic resonance imaging brain scans at age 9 (N = 190) and 12 (N = 125). High heritability estimates were found at both ages for height and brain volumes (49–96%), and high genetic correlation between ages were observed (rg > 0.89). With increasing age, whole brain (+1.1%), cerebellum (+4.2%), cerebral white matter (+5.1%), and lateral ventricle (+9.4%) volumes increased, and third ventricle (−4.0%) and cerebral gray matter (−1.6%) volumes decreased. Children increased on ... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5470285 Sat, 03 Dec 2011 05:00:00 +0100 5470285 http://www.medworm.com/index.php?rid=5470284&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21486 AbstractQuantification of brain development as well as disease‐induced pathologies in neonates often requires precise delineation of white matter, grey matter and cerebrospinal fluid. Unlike adults, tissue segmentation in neonates is significantly more challenging due to the inherently lower tissue contrast. Most existing methods take a voxel‐based approach and are limited to working with images from a single time‐point, even though longitudinal scans are available. We take a different approach by taking advantage of the fact that the pattern of the major sulci and gyri are already present in the neonates and generally preserved but fine‐tuned during brain development. That is, the segmentation of late‐time‐point image can be used to guide the segmentation of neonatal image. Ac... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5470284 Sat, 03 Dec 2011 05:00:00 +0100 5470284 http://www.medworm.com/index.php?rid=5470283&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21491 This study assessed relationships between body mass index (BMI) and values of DTI parameters among 51 normal weight (lean), overweight, and obese participants who were otherwise healthy. BMI correlated negatively with fractional anisotropy and axial eigenvalues (λ1) in the body of corpus callosum (CC), positively with mean diffusivity and radial eigenvalues (λ⟂) in the fornix and splenium of CC, and positively with λ1 in the right corona radiata (CR) and superior longitudinal fasciculus (SLF). These data indicate that BMI correlates negatively with WM integrity in the fornix and CC. Furthermore, the different patterns of BMI‐related differences in DTI parameters at the fornix, body, and splenium of the CC, and the right CR and SLF suggest that different biological processes may unde... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5470283 Sat, 03 Dec 2011 05:00:00 +0100 5470283 http://www.medworm.com/index.php?rid=5488530&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21503 AbstractThe anterior insula and the dorsal anterior cingulate cortex (ACC) are regarded as key brain structures associated with the integration of perceived phobic characteristics of external stimuli and the perception of ones own body responses that leads to emotional feelings. To test to what extent the activity in these two brain structures anatomically and functionally overlap during phobic reactions and interoception, we submitted the same group of phobic participants (n = 29; either spider or blood‐injection‐injury (BII) phobics) and controls (n = 17) to both type of experimental paradigms. Results showed that there was a clear anatomical overlap in the Blood Oxygen Level‐Dependent (BOLD) responses within the anterior insula and ACC elicited during phobic symptom provocation an... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5488530 Thu, 01 Dec 2011 05:00:00 +0100 5488530 http://www.medworm.com/index.php?rid=5470282&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21492 We examined this relationship in the brain of healthy young adult men [n = 74, mean age = 21.5 years, standard deviation (SD) = 1.6] and women (n = 44, mean age = 21.9 years, SD = 1.4). We performed a voxel‐based analysis of fractional anisotropy, which is an indicator of WM integrity, using diffusion tensor imaging and used a questionnaire (EI Scale) for measuring EI to identify the correlation of WM integrity with individual EI factor (intrapersonal, interpersonal, and situation management factors). Our results showed that (a) the intrapersonal factor of EI was positively correlated with WM integrity in the right anterior insula, and (b) the interpersonal factor of EI was associated with WM integrity in a part of the right inferior longitudinal fasciculus (ILF). The right anterior insu... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5470282 Thu, 01 Dec 2011 05:00:00 +0100 5470282 http://www.medworm.com/index.php?rid=5459560&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21416 AbstractA meta‐analysis of 140 neuroimaging studies was performed using the activation‐likelihood‐estimate (ALE) method to explore the location and extent of activation in the brain in response to noxious stimuli in healthy volunteers. The first analysis involved the creation of a likelihood map illustrating brain activation common across studies using noxious stimuli. The left thalamus, right anterior cingulate cortex (ACC), bilateral anterior insulae, and left dorsal posterior insula had the highest likelihood of being activated. The second analysis contrasted noxious cold with noxious heat stimulation and revealed higher likelihood of activation to noxious cold in the subgenual ACC and the amygdala. The third analysis assessed the implications of using either a warm stimulus or a ... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5459560 Thu, 01 Dec 2011 05:00:00 +0100 5459560 http://www.medworm.com/index.php?rid=5459563&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21480 AbstractDespite the crucial role of touch in social development, there is very little functional magnetic resonance imaging (fMRI) research on brain mechanisms underlying social touch processing. The “skin as a social organ” hypothesis is supported by the discovery of C‐tactile (CT) nerves that are present in hairy skin and project to the insular cortex. CT‐fibers respond specifically well to slow, gentle touch such as that which occurs during close social interactions. Given the social significance of such touch researchers have proposed that the CT‐system represents an evolutionarily conserved mechanism important for normative social development. However, it is currently unknown whether brain regions other than the insula are involved in processing CT‐targeted touch. In the c... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5459563 Tue, 29 Nov 2011 05:00:00 +0100 5459563 http://www.medworm.com/index.php?rid=5459562&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21489 AbstractWhile the left angular gyrus (lAG) has been repeatedly implicated in mental arithmetic, its precise functional role has not been established. On the one hand, it has been speculated that the lAG is involved in task‐specific processes. On the other hand, the observation of relative deactivation during arithmetic has led to the contention that differential lAG activation reflects task‐unrelated difficulty effects associated with the default mode network (DMN). Using functional magnetic resonance imaging, we investigated the neural correlates of the associative confusion effect that allowed us to dissociate effects of task difficulty and task‐related arithmetic processes on lAG activation. The associative confusion effect is characterized by poorer performance while verifying ad... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5459562 Tue, 29 Nov 2011 05:00:00 +0100 5459562 http://www.medworm.com/index.php?rid=5459561&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21471 AbstractPlacebo analgesia (PA) is one of the most studied placebo effects. Brain imaging studies published over the last decade, using either positron emission tomography (PET) or functional magnetic resonance imaging (fMRI), suggest that multiple brain regions may play a pivotal role in this process. However, there continues to be much debate as to which areas consistently contribute to placebo analgesia‐related networks. In the present study, we used activation likelihood estimation (ALE) meta‐analysis, a state‐of‐the‐art approach, to search for the cortical areas involved in PA in human experimental pain models. Nine fMRI studies and two PET studies investigating cerebral hemodynamic changes were included in the analysis. During expectation of analgesia, activated foci were fo... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5459561 Tue, 29 Nov 2011 05:00:00 +0100 5459561 http://www.medworm.com/index.php?rid=5450297&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21418 In conclusion, our results add further evidence in support to the notion that CBF provides a more accurate localization of motor activation than BOLD contrast, indicating that ASL may be an appropriate technique for clinical fMRI studies. Hum Brain Mapp, 2011. © 2011 Wiley‐Liss, Inc. (Source: Human Brain Mapping) Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5450297 Mon, 28 Nov 2011 13:44:19 +0100 5450297 http://www.medworm.com/index.php?rid=5450299&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21487 We present a technique for predicting cardiac and respiratory phase on a time point by time point basis, from fMRI image data. These predictions have utility in attempts to detrend effects of the physiological cycles from fMRI image data. We demonstrate the technique both in the case where it can be trained on a subject's own data, and when it cannot. The prediction scheme uses a multiclass support vector machine algorithm. Predictions are demonstrated to have a close fit to recorded physiological phase, with median Pearson correlation scores between recorded and predicted values of 0.99 for the best case scenario (cardiac cycle trained on a subject's own data) down to 0.83 for the worst case scenario (respiratory predictions trained on group data), as compared to random chance correlation... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5450299 Mon, 28 Nov 2011 05:00:00 +0100 5450299 http://www.medworm.com/index.php?rid=5450298&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21452 AbstractThe ability to detect single trial responses in functional magnetic resonance imaging (fMRI) studies is essential, particularly if investigating learning or adaptation processes or unpredictable events. We recently introduced paradigm free mapping (PFM), an analysis method that detects single trial blood oxygenation level dependent (BOLD) responses without specifying prior information on the timing of the events. PFM is based on the deconvolution of the fMRI signal using a linear hemodynamic convolution model. Our previous PFM method (Caballero‐Gaudes et al., 2011: Hum Brain Mapp) used the ridge regression estimator for signal deconvolution and required a baseline signal period for statistical inference. In this work, we investigate the application of sparse regression techniques... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5450298 Mon, 28 Nov 2011 05:00:00 +0100 5450298 http://www.medworm.com/index.php?rid=5442996&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21472 AbstractCognitive performance is affected by motivation. Few studies, however, have investigated the neural mechanisms of the influence of motivation through potential monetary punishment on working memory. We employed functional MRI during a delayed recognition task that manipulated top‐down control demands with added monetary incentives to some trials in the form of potential losses of bonus money. Behavioral performance on the task was influenced by loss‐threatening incentives in the form of faster and more accurate performance. As shown previously, we found enhancement of activity for relevant stimuli occurs throughout all task periods (e.g., stimulus encoding, maintenance, and response) in both prefrontal and visual association cortex. Further, these activation patterns were enhan... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5442996 Fri, 25 Nov 2011 13:34:33 +0100 5442996 http://www.medworm.com/index.php?rid=5442997&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21464 AbstractSimple writer's cramp (WC) is a task‐specific form of dystonia, characterized by abnormal movements and postures of the hand during writing. It is extremely task‐specific, since dystonic symptoms can occur when a patient uses a pencil for writing, but not when it is used for sharpening. Maladaptive plasticity, loss of inhibition, and abnormal sensory processing are important pathophysiological elements of WC. However, it remains unclear how those elements can account for its task‐specificity. We used fMRI to isolate cerebral alterations associated with the task‐specificity of simple WC. Subjects (13 simple WC patients, 20 matched controls) imagined grasping a pencil to either write with it or sharpen it. On each trial, we manipulated the pencil's position and the number of ... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5442997 Thu, 24 Nov 2011 05:00:00 +0100 5442997 http://www.medworm.com/index.php?rid=5443008&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21456 Conclusions: These findings support the hypothesis that DA release in mOFC, vmPFC, and dACC regions plays an important role in reinforcement learning in the human brain. Hum Brain Mapp, 2011. © 2011 Wiley Periodicals, Inc. (Source: Human Brain Mapping) Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5443008 Wed, 23 Nov 2011 05:00:00 +0100 5443008 http://www.medworm.com/index.php?rid=5443007&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21460 This study was undertaken to investigate the reciprocity effect between postural and suprapostural performances and its underlying neural mechanisms wherein subjects executed a perceptual‐motor suprapostural task and maintained steady upright postures. Fourteen healthy individuals conducted force‐matching maneuvers (static vs. dynamic) under two stance conditions (bipedal stance vs. unipedal stance); meanwhile, force‐matching error, center of pressure dynamics, event‐related potentials (ERPs), and the movement‐related potential (MRP) were monitored. The behavioral results showed that force‐matching error and postural sway were differently modulated by variations in stance pattern and force‐matching version. Increase in postural challenge undermined the precision of static for... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5443007 Wed, 23 Nov 2011 05:00:00 +0100 5443007 http://www.medworm.com/index.php?rid=5443006&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21463 AbstractThe pathophysiology of auditory verbal hallucinations (AVH) is still unclear. Cognitive as well as electrophysiological studies indicate that a defect in sensory feedback (corollary discharge) may contribute to the experience of AVH. This could result from disruption of the arcuate fasciculus, the major tract connecting frontal and temporo‐parietal language areas. Previous diffusion tensor imaging studies indeed demonstrated abnormalities of this tract in schizophrenia patients with AVH. It is, however, difficult to disentangle specific associations with AVH in this patient group as many other factors, such as other positive and negative symptoms, medication or halted education could likewise have affected tract integrity. We therefore investigated AVH in relative isolation and s... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5443006 Wed, 23 Nov 2011 05:00:00 +0100 5443006 http://www.medworm.com/index.php?rid=5443005&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21467 This study compared the neural circuits associated with the production of static force to those associated with the production of dynamic force pulses. To that end, healthy young adults (n = 17) completed static and dynamic precision grip force tasks during functional magnetic resonance imaging (fMRI). Both tasks activated core regions within the visuomotor network, including primary and sensory motor cortices, premotor cortices, multiple visual areas, putamen, and cerebellum. Static force was associated with unique activity in a right‐lateralized cortical network including inferior parietal lobe, ventral premotor cortex, and dorsolateral prefrontal cortex. In contrast, dynamic force was associated with unique activity in left‐lateralized and midline cortical regions, including supplem... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5443005 Wed, 23 Nov 2011 05:00:00 +0100 5443005 http://www.medworm.com/index.php?rid=5443004&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21483 In this study, the effect of the neonatal fontanel was investigated by predicting photon propagation using a probabilistic Monte Carlo approach. Two anatomical newborn head models were created from computed tomography and magnetic resonance images: (1) a realistic model including the fontanel tissue and (2) a model in which the fontanel was replaced by skull tissue. Quantitative change in absorption due to simulated activation was compared for the two models for specific regions of activation and optical arrays simulated in the temporal area. A correction factor was computed to quantify the effect of the fontanel and defined by the ratio between the true and recovered change. The results show that recovered changes in absorption were more precise when determined with the anatomical model i... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5443004 Wed, 23 Nov 2011 05:00:00 +0100 5443004 http://www.medworm.com/index.php?rid=5443003&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21484 AbstractSemantic (svPPA) and nonfluent (nfPPA) variants of primary progressive aphasia are associated with distinct patterns of cortical atrophy and underlying pathology. Little is known, however, about their contrasting spread of white matter disruption and how this relates to grey matter (GM) loss. We undertook a structural MRI study to investigate this relationship. We used diffusion tensor imaging, tract‐based spatial statistics, and voxel‐based morphometry to examine fractional anisotropy (FA) and directional diffusivities in nine patients with svPPA and nine patients with nfPPA, and compared them to 16 matched controls after accounting for global GM atrophy. Significant differences in topography of white matter changes were found, with more ventral involvement in svPPA patients a... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5443003 Wed, 23 Nov 2011 05:00:00 +0100 5443003 http://www.medworm.com/index.php?rid=5443002&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21470 Conclusions: Increased neuronal activation in OTCD subjects despite equivalent task performance points to sub‐optimal activation of the working memory network in these subjects, most likely reflecting damage caused by hyperammonemic events. These increases directly relate to our previous finding of reduced frontal white matter integrity in the superior extents of the corpus callosum; key hemispheric connections for these areas. Future studies using higher cognitive load are required to further characterize these effects. Hum Brain Mapp, 2011. © 2011 Wiley Periodicals, Inc. (Source: Human Brain Mapping) Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5443002 Wed, 23 Nov 2011 05:00:00 +0100 5443002 http://www.medworm.com/index.php?rid=5443001&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21474 In conclusion, neural activity distinguishing old from new events comprises an ensemble of multiple memory‐specific activities, including encoding, retrieval, and priming, as well as multiple types of more general cognitive activities, including default‐mode, cognitive‐control, and reward processing. Hum Brain Mapp, 2011. © 2011 Wiley Periodicals, Inc. (Source: Human Brain Mapping) Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5443001 Wed, 23 Nov 2011 05:00:00 +0100 5443001 http://www.medworm.com/index.php?rid=5443000&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21477 In conclusion, there are a number of differences in WM integrity between human brain hemispheres. Specially, the anisotropy asymmetry in inferior frontal ACR plays a crucial role in EC function. Our finding is supportive of the functional studies of inferior frontal regions and in keeping with the theory of the brain lateralization on human ventral attention system. Hum Brain Mapp, 2011. © 2011 Wiley Periodicals, Inc. (Source: Human Brain Mapping) Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5443000 Wed, 23 Nov 2011 05:00:00 +0100 5443000 http://www.medworm.com/index.php?rid=5442999&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21478 AbstractExtra‐striate regions are thought to receive non‐retinal signals from the pursuit system to maintain perceptual stability during eye movements. Here, we used magnetoencephalography (MEG) to study changes in oscillatory power related to smooth pursuit in extra‐striate visual areas under three conditions: ‘pursuit’ of a small target, ‘retinal motion’ of a large background and ‘pursuit + retinal motion’ combined. All stimuli moved sinusoidally. MEG source reconstruction was performed using synthetic aperture magnetometry. Broadband alpha–beta suppression (5–25 Hz) was observed over bilateral extra‐striate cortex (consistent with middle temporal cortex (MT+)) during all conditions. A functional magnetic resonance imaging study using the same experimental protoco... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5442999 Wed, 23 Nov 2011 05:00:00 +0100 5442999 http://www.medworm.com/index.php?rid=5442998&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21479 AbstractThe need for realistic electric field calculations in human noninvasive brain stimulation is undisputed to more accurately determine the affected brain areas. However, using numerical techniques such as the finite element method (FEM) is methodologically complex, starting with the creation of accurate head models to the integration of the models in the numerical calculations. These problems substantially limit a more widespread application of numerical methods in brain stimulation up to now. We introduce an optimized processing pipeline allowing for the automatic generation of individualized high‐quality head models from magnetic resonance images and their usage in subsequent field calculations based on the FEM. The pipeline starts by extracting the borders between skin, skull, c... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5442998 Wed, 23 Nov 2011 05:00:00 +0100 5442998 http://www.medworm.com/index.php?rid=5423731&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21466 AbstractOcclusal splints are a common and effective therapy for temporomandibular joint disorder. Latest hypotheses on the impact of occlusal splints suggest an altered cerebral control on the occlusion movements after using a splint. However, the impact of using a splint during chewing on its cerebral representation is quite unknown. We used functional magnetic resonance imaging (fMRI) to investigate brain activities during occlusal function in centric occlusion on natural teeth or on occlusal splints in fifteen healthy subjects. Comparisons between conditions revealed an increased activation for the bilateral occlusion without a splint in bilateral primary and secondary sensorimotor areas, the putamen, inferior parietal and prefrontal cortex (left dorsal and bilateral orbital) and anteri... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5423731 Sat, 19 Nov 2011 13:47:44 +0100 5423731 http://www.medworm.com/index.php?rid=5423742&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21449 AbstractTRACK‐HD is a multicentre longitudinal observational study investigating the use of clinical assessments and 3‐Tesla magnetic resonance imaging as potential biomarkers for future therapeutic trials in Huntington's disease (HD). The cross‐sectional data from this large well‐characterized dataset provide the opportunity to improve our knowledge of how the underlying neuropathology of HD may contribute to the clinical manifestations of the disease across the spectrum of premanifest (PreHD) and early HD. Two hundred and thirty nine gene‐positive subjects (120 PreHD and 119 early HD) from the TRACK‐HD study were included. Using voxel‐based morphometry (VBM), grey and white matter volumes were correlated with performance in four domains: quantitative motor (tongue force, me... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5423742 Fri, 18 Nov 2011 05:00:00 +0100 5423742 http://www.medworm.com/index.php?rid=5423741&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21450 AbstractLinking observed and executable actions appears to be achieved by an action observation network (AON), comprising parietal, premotor, and occipitotemporal cortical regions of the human brain. AON engagement during action observation is thought to aid in effortless, efficient prediction of ongoing movements to support action understanding. Here, we investigate how the AON responds when observing and predicting actions we cannot readily reproduce before and after visual training. During pre‐ and posttraining neuroimaging sessions, participants watched gymnasts and wind‐up toys moving behind an occluder and pressed a button when they expected each agent to reappear. Between scanning sessions, participants visually trained to predict when a subset of stimuli would reappear. Posttra... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5423741 Fri, 18 Nov 2011 05:00:00 +0100 5423741 http://www.medworm.com/index.php?rid=5423740&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21458 We examined the common and distinct features of the neural activity underlying evaluation of emotional and bodily state using functional magnetic resonance imaging (fMRI). The right anterior insular cortex and ventromedial prefrontal cortex (VMPFC) were identified as commonly activated areas. As both of these areas are considered critical for interoceptive awareness, these results suggest that attending to the bodily state underlies awareness of one's emotional state. Uniquely activated areas involved in the evaluation of emotional state included the temporal pole, posterior and anterior cingulate cortex, medial frontal gyrus, and inferior frontal gyrus. Also the precuneus was functionally associated with activity of the right anterior insular cortex and VMPFC when evaluating emotional sta... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5423740 Fri, 18 Nov 2011 05:00:00 +0100 5423740 http://www.medworm.com/index.php?rid=5423739&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21459 AbstractPrevious investigations of the default‐mode network (DMN) in persons with attention‐deficit/hyperactivity disorder (ADHD) have shown reduced functional connectivity between the anterior and posterior aspects. This finding was originally demonstrated in adults with ADHD, then in youth with ADHD, and has been tentatively linked to ultra low frequency oscillations within the DMN. The current study evaluates the specificity of DMN abnormalities to neuronal oscillations in the ultra low frequency range, and examines the regional specificity of these DMN aberrations in medicated and unmedicated adults with, and those without ADHD. An individually matched sample of adults with and without ADHD completed 6‐minute sessions of resting‐state magnetoencephalography (MEG). Participants ... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5423739 Fri, 18 Nov 2011 05:00:00 +0100 5423739 http://www.medworm.com/index.php?rid=5423738&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21461 We describe modifications that improve the reliability and efficiency of this method. First, we find that increasing the number and size of visual stimuli results in source estimates that are less susceptible to noise. Second, to create a more accurate forward solution, we have explicitly modeled the cortical point spread of individual visual stimuli. Dipoles are represented as extended patches on the cortical surface, which take into account the estimated receptive field size at each location in V1, V2, and V3 as well as the contributions from contralateral, ipsilateral, dorsal, and ventral portions of the visual areas. Third, we implemented a map fitting procedure to deform a template to match individual subject retinotopic maps derived from functional magnetic resonance imaging (fMRI). ... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5423738 Fri, 18 Nov 2011 05:00:00 +0100 5423738 http://www.medworm.com/index.php?rid=5423737&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21462 AbstractLinear statistical models are used very effectively to assess task‐related differences in EEG power spectral analyses. Mixed models, in particular, accommodate more than one variance component in a multisubject study, where many trials of each condition of interest are measured on each subject. Generally, intra‐ and intersubject variances are both important to determine correct standard errors for inference on functions of model parameters, but it is often assumed that intersubject variance is the most important consideration in a group study. In this article, we show that, under common assumptions, estimates of some functions of model parameters, including estimates of task‐related differences, are properly tested relative to the intrasubject variance component only. A subst... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5423737 Fri, 18 Nov 2011 05:00:00 +0100 5423737 http://www.medworm.com/index.php?rid=5423736&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21481 AbstractTurner syndrome (TS) is a noninherited genetic disorder caused by the absence of one or part of one X chromosome. It is characterized by physical and cognitive phenotypes that include motor deficits that may be related to neuroanatomical abnormalities of sensorimotor pathways. Here, we used transcranial magnetic stimulation (TMS) and cortical thickness analysis to assess motor cortex excitability and cortical morphology in 17 individuals with TS (45, X) and 17 healthy controls. Exploratory analysis was performed to detect the effect of parental origin of the X chromosome (Xmat, Xpat) on both measures. Results showed that long‐interval intracortical inhibition was reduced and motor threshold (MT) was increased in TS relative to controls. Areas of reduced thickness were observed in... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5423736 Fri, 18 Nov 2011 05:00:00 +0100 5423736 http://www.medworm.com/index.php?rid=5423735&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21473 AbstractElectroencephalography (EEG) and magnetoencephalography (MEG) have different sensitivities to differently configured brain activations, making them complimentary in providing independent information for better detection and inverse reconstruction of brain sources. In the present study, we developed an integrative approach, which integrates a novel sparse electromagnetic source imaging method, i.e., variation‐based cortical current density (VB‐SCCD), together with the combined use of EEG and MEG data in reconstructing complex brain activity. To perform simultaneous analysis of multimodal data, we proposed to normalize EEG and MEG signals according to their individual noise levels to create unit‐free measures. Our Monte Carlo simulations demonstrated that this integrative appro... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5423735 Fri, 18 Nov 2011 05:00:00 +0100 5423735 http://www.medworm.com/index.php?rid=5423734&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21451 AbstractThe medial temporal lobes (MTL) and frontal cortex have been shown to subserve memory processes. Neurodegenerative diseases, such as Alzheimer's disease (AD), disrupt the neuronal networks that underlie memory processing. The ε4 allele of the apolipoprotein E gene is a genetic risk factor for AD and is associated with decrements in memory and in olfactory function. The present study utilized EQS, a structural equation modeling software program, to examine differences in the neuronal networks between non‐demented ε4 carriers and ε4 noncarriers during a cross‐modal olfactory recognition memory paradigm. Prior to fMRI scanning, participants were presented with 16 odors. During two scans, participants discriminated between names of odors presented before scanning (targets) or no... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5423734 Fri, 18 Nov 2011 05:00:00 +0100 5423734 http://www.medworm.com/index.php?rid=5423733&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21453 AbstractA fundamental question with regard to perceptual development is how multisensory information is processed in the brain during the early stages of development. Although a growing body of evidence has shown the early emergence of modality‐specific functional differentiation of the cortical regions, the interplay between sensory inputs from different modalities in the developing brain is not well understood. To study the effects of auditory input during audio‐visual processing in 3‐month‐old infants, we evaluated the spatiotemporal cortical hemodynamic responses of 50 infants while they perceived visual objects with or without accompanying sounds. The responses were measured using 94‐channel near‐infrared spectroscopy over the occipital, temporal, and frontal cortices. The... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5423733 Fri, 18 Nov 2011 05:00:00 +0100 5423733 http://www.medworm.com/index.php?rid=5423732&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21457 AbstractThe neural events that lead to successful or failed detection of suprathreshold sounds are not well established. In this experiment, event‐related potentials (ERPs) and functional magnetic resonance imaging (fMRI) were recorded while participants performed two tasks: a primary difficult duration judgment task on a sequence of tones presented to one ear, and a secondary target detection task on an auditory oddball stream presented to the other ear. The paradigm was designed to elicit competition and variability in detection of auditory targets despite identical input. Successful detection of auditory targets was associated mainly with greater fMRI activity in superior parietal cortex and thalamus. In the ERPs, successful detection was linked with a larger fronto‐central negativi... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5423732 Fri, 18 Nov 2011 05:00:00 +0100 5423732 http://www.medworm.com/index.php?rid=5410473&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21448 AbstractFunctional magnetic resonance imaging (fMRI) is able to detect changes in blood oxygenation level associated with neuronal activity throughout the brain. For more than a decade, fMRI alone or in combination with simultaneous EEG recording (EEG‐fMRI) has been used to investigate the hemodynamic changes associated with interictal and ictal epileptic discharges. This is the first literature review to focus on the various fMRI acquisition and data analysis methods applied to map epileptic seizure‐related hemodynamic changes from the first report of an fMRI scan of a seizure to the present day. Two types of data analysis approaches, based on temporal correlation and data driven, are explained and contrasted. The spatial and temporal relationship between the observed hemodynamic chan... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5410473 Thu, 17 Nov 2011 04:25:23 +0100 5410473 http://www.medworm.com/index.php?rid=5401673&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21455 AbstractPrevious studies have shown that healthy anatomical as well as functional brain networks have small‐world properties and become less optimal with brain disease. During sleep, the functional brain network becomes more small‐world‐like. Here we test the hypothesis that the functional brain network during wakefulness becomes less optimal after sleep deprivation (SD). Electroencephalography (EEG) was recorded five times a day after a night of SD and after a night of normal sleep in eight young healthy subjects, both during eyes‐closed and eyes‐open resting state. Overall synchronization was determined with the synchronization likelihood (SL) and the phase lag index (PLI). From these coupling strength matrices the normalized clustering coefficient C (a measurement of local clu... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5401673 Sun, 13 Nov 2011 13:12:21 +0100 5401673 http://www.medworm.com/index.php?rid=5401678&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21440 AbstractDiffering imaging modalities provide unique channels of information to probe differing aspects of the brain's structural or functional organization. In combination, differing modalities provide complementary and mutually informative data about tissue organization that is more than their sum. We acquired and spatially coregistered data in four MRI modalities—anatomical MRI, functional MRI, diffusion tensor imaging (DTI), and magnetic resonance spectroscopy (MRS)—from 20 healthy adults to understand how interindividual variability in measures from one modality account for variability in measures from other modalities at each voxel of the brain. We detected significant correlations of local volumes with the magnitude of functional activation, suggesting that underlying variation i... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5401678 Fri, 11 Nov 2011 05:00:00 +0100 5401678 http://www.medworm.com/index.php?rid=5401677&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21443 AbstractThe dorsal frontal‐striatal circuit is implicated in executive functions, such as planning. The Tower of London task, a planning task, in combination with off‐line low‐frequency repetitive transcranial magnetic stimulation (rTMS), was used to investigate whether interfering with dorsolateral prefrontal function would modulate executive performance, mimicking dorsal frontal‐striatal dysfunction as found in neuropsychiatric disorders. Eleven healthy controls (seven females; mean age 25.5 years) were entered in a cross‐over design: two single‐session treatments of low‐frequency (1 Hz) rTMS (vs. sham rTMS) for 20 min on the left dorsolateral prefrontal cortex (DLPFC). Directly following the off‐line rTMS treatment, the Tower of London task was performed during MRI measu... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5401677 Fri, 11 Nov 2011 05:00:00 +0100 5401677 http://www.medworm.com/index.php?rid=5401676&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21444 AbstractNetworks of functional connectivity are highly consistent across participants, suggesting that functional connectivity is for a large part predetermined. However, several studies have shown that functional connectivity may change depending on instructions or previous experience. In the present study, we investigated whether 6 weeks of practice with a working memory task changes functional connectivity during a resting period preceding the task. We focused on two task‐relevant networks, the frontoparietal network and the default network, using seed regions in the right middle frontal gyrus (MFG) and the medial prefrontal cortex (PFC), respectively. After practice, young adults showed increased functional connectivity between the right MFG and other regions of the frontoparietal ne... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5401676 Fri, 11 Nov 2011 05:00:00 +0100 5401676 http://www.medworm.com/index.php?rid=5401675&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21446 Conclusions: The neural correlate of trait impulsiveness in the OFC matches an area where brain function has previously been related to inhibitory control. Additionally, orbitofrontal GM volume was associated with scores for perceptual reasoning. The data show for the first time structural correlates of both cognitive functioning and impulsiveness in healthy adolescent subjects. Hum Brain Mapp, 2011. © 2011 Wiley Periodicals, Inc. (Source: Human Brain Mapping) Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5401675 Fri, 11 Nov 2011 05:00:00 +0100 5401675 http://www.medworm.com/index.php?rid=5401674&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21447 AbstractInvestigation of the brain's white matter fiber tracts in social anxiety disorder (SAD) may provide insight into the underlying pathophysiology. Because models of pathological anxiety posit altered frontolimbic interactions, the uncinate fasciculus (UF) connecting (orbito‐) frontal and temporal areas including the amygdala is of particular interest. Microstructural alterations in parts of the UF have been reported previously, whereas examination of the UF as discrete fiber tract with regard to more large‐scale properties is still lacking. Diffusion tensor imaging was applied in 25 patients with generalized SAD and 25 healthy control subjects matched by age and gender. By means of fiber tractography, the UF was reconstructed for each participant. The inferior fronto‐occipital ... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5401674 Fri, 11 Nov 2011 05:00:00 +0100 5401674 http://www.medworm.com/index.php?rid=5365459&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21438 AbstractA characterization of the impact of natural disasters on the brain of survivors is critical for a better understanding of posttraumatic responses and may inform the development of more effective early interventions. Here we report alterations in white matter microstructure in survivors soon after Wenchuan earthquake in China in 2008. Within 25 days after the Wenchuan earthquake, 44 healthy survivors were recruited and scanned on a 3T MR imaging system. The survivors were divided into two groups according to their self‐rating anxiety scale (SAS) score, including the SAS(+) (SAS > 55 after correction) group and “SAS(−)” (SAS < 55 after correction) group. Thrity‐two healthy volunteers were also recruited as control group before earthquake. Individual maps of fractional... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5365459 Tue, 01 Nov 2011 04:00:00 +0100 5365459 http://www.medworm.com/index.php?rid=5365463&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21433 In this study, transcranial magnetic stimulation was used to examine the involvement of three areas in the undamaged brain, while participants completed a conjunction search task in near and far space. The brain areas investigated were right posterior parietal cortex (rPPC), right frontal eye field (rFEF), and right ventral occipital cortex (rVO), each of which has been implicated in visuospatial processing. The results revealed a double dissociation, whereby rPPC was involved for search in near space only, whilst rVO only became necessary when the task was completed in far space. These data provide clear evidence for a dorsal and ventral dissociation between the processing of near and far space, which is compatible with the functional roles previously attributed to the two streams. For ex... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5365463 Mon, 31 Oct 2011 04:00:00 +0100 5365463 http://www.medworm.com/index.php?rid=5365462&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21434 AbstractGenome‐wide association studies identified the single nucleotide polymorphism rs1344706 in ZNF804A as a common risk‐variant for schizophrenia and bipolar disorder. Whereas the molecular function of ZNF804A is yet unclear, recent imaging genetics studies have started to characterize the neural systems architecture linking rs1344706 genotype to psychosis. Carring rs1344706 risk‐alleles was associated with a decrease in functional connectivity within the dorsolateral prefrontal cortices (DLPFCs) as well as an increase in connectivity between the DLPFC and the hippocampal formation (HF) in the context of a working memory task. The present study aimed at replicating these findings in an independent sample of 94 healthy subjects. Subjects were genotyped for rs1344706 and performed ... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5365462 Mon, 31 Oct 2011 04:00:00 +0100 5365462 http://www.medworm.com/index.php?rid=5365461&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21435 AbstractNew episodic memory traces represent a record of the ongoing neocortical processing engaged during memory formation (encoding). Thus, during encoding, deep (semantic) processing typically establishes more distinctive and retrievable memory traces than does shallow (perceptual) processing, as assessed by later episodic memory tests. By contrast, the hippocampus appears to play a processing‐independent role in encoding, because hippocampal lesions impair encoding regardless of level of processing. Here, we clarified the neural relationship between processing and encoding by examining hippocampal–cortical connectivity during deep and shallow encoding. Participants studied words during functional magnetic resonance imaging and freely recalled these words after distraction. Deep stu... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5365461 Mon, 31 Oct 2011 04:00:00 +0100 5365461 http://www.medworm.com/index.php?rid=5365460&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21437 AbstractRecent studies have demonstrated neuroanatomically selective relationships among white matter tract microstructure, physiological function, and task performance. Such findings suggest that the microstructure of transcallosal motor fibers may reflect the capacity for interhemispheric inhibition between the primary motor cortices, although full characterization of the transcallosal inhibitory sensorimotor network is lacking. Thus, the goal of this study was to provide a comprehensive description of transcallosal fibers connecting homologous sensorimotor cortical regions and to identify the relationship(s) between fiber tract microstructure and interhemispheric inhibition during voluntary cortical activity. To this end, we assessed microstructure of fiber tracts connecting homologous ... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5365460 Mon, 31 Oct 2011 04:00:00 +0100 5365460 http://www.medworm.com/index.php?rid=5365464&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21432 AbstractWe aimed to identify the brain areas involved in verbal and visual memory processing in normal controls and patients with unilateral mesial temporal lobe epilepsy (MTLE) associated with unilateral hippocampal sclerosis (HS) by means of functional magnetic resonance imaging (fMRI). The sample comprised nine normal controls, eight patients with right MTLE, and nine patients with left MTLE. All subjects underwent fMRI with verbal and visual memory paradigms, consisting of encoding and immediate recall of 17 abstract words and 17 abstract drawings. A complex network including parietal, temporal, and frontal cortices seems to be involved in verbal memory encoding and retrieval in normal controls. Although similar areas of activation were identified in both patient groups, the extension ... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5365464 Sun, 30 Oct 2011 04:00:00 +0100 5365464 http://www.medworm.com/index.php?rid=5338159&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21445 We examined the ratio of lesion to nonlesioned white matter tissue within multiple fiber tracts between depressed and nondepressed elders. We also sought to determine if the AGTR1 A1166C and BDNF Val66Met polymorphisms contributed to vulnerability to lesion development in discrete tracts. The 3T structural MR images and blood samples for genetic analyses were acquired on 54 depressed and 37 nondepressed elders. Lesion maps were created through an automated tissue segmentation process and applied to a probabilistic white matter fiber tract atlas allowing for identification of the fraction of the tract occupied by lesion. The depressed cohort exhibited a significantly greater lesion ratio only in the left upper cingulum near the cingulate gyrus (F(1,86) = 4.62, P = 0.0344), supporting past w... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5338159 Sun, 23 Oct 2011 02:20:50 +0100 5338159 http://www.medworm.com/index.php?rid=5338167&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21414 In conclusion, this study demonstrates the congruent odor‐induced saltiness enhancement on the basis of psychophysical and neuroanatomical results. These findings support an alternative strategy to reduce excessive salt intake by adding salty‐congruent aroma to sodium reduced food. However, there are open questions regarding the salty‐congruent odor‐induced taste unpleasantness. Hum Brain Mapp, 2011. © 2011 Wiley Periodicals, Inc. (Source: Human Brain Mapping) Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5338167 Sat, 22 Oct 2011 04:00:00 +0100 5338167 http://www.medworm.com/index.php?rid=5338166&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21417 AbstractAnimal models of stroke demonstrated that white matter ischemia may cause both axonal damage and myelin degradation distant from the core lesion, thereby impacting on behavior and functional outcome after stroke. We here used parameters derived from diffusion magnetic resonance imaging (MRI) to investigate the effect of focal white matter ischemia on functional reorganization within the motor system. Patients (n = 18) suffering from hand motor deficits in the subacute or chronic stage after subcortical stroke and healthy controls (n = 12) were scanned with both diffusion MRI and functional MRI while performing a motor task with the left or right hand. A laterality index was employed on activated voxels to assess functional reorganization across hemispheres. Regression analyses reve... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5338166 Sat, 22 Oct 2011 04:00:00 +0100 5338166 http://www.medworm.com/index.php?rid=5338165&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21419 AbstractIntra‐active touch (IAT) is a process that involves a body part doing the touching (active touch [AT]) and another body part being touched (passive touch [PT]) simultaneously. The brain representation related to IAT is still unclear. A total of 23 subjects carried out angle discrimination under PT, AT and IAT conditions with functional magnetic resonance imaging. All of the tasks were strictly dependent on cutaneous feedback from the finger(s). As the subjects were able to perceive the angle stimuli from the right (touching) and left (touched) sides during the IAT condition, we expected there would be greater brain activation with the IAT condition than for the AT or PT condition. Therefore, we hypothesized that the region within and/or around the intraparietal sulcus (IPS) and t... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5338165 Sat, 22 Oct 2011 04:00:00 +0100 5338165 http://www.medworm.com/index.php?rid=5338164&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21425 AbstractAdvantageous economic decision making requires flexible adaptation of gain‐based and loss‐based preference hierarchies. However, where the neuronal blueprints for economic preference hierarchies are kept and how they may be adapted remains largely unclear. Phasic cortical dopamine release likely mediates flexible adaptation of neuronal representations. In this PET study, cortical‐binding potential (BP) for the D2‐dopamine receptor ligand [11C]FLB 457 was examined in healthy participants during multiple sessions of a probabilistic four‐choice financial decision‐making task with two behavioral variants. In the changing‐gains/constant‐losses variant, the implicit gain‐based preference hierarchy was unceasingly changing, whereas the implicit loss‐based preference hi... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5338164 Sat, 22 Oct 2011 04:00:00 +0100 5338164 http://www.medworm.com/index.php?rid=5338163&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21426 AbstractCerebral 18F‐deoxyglucose positron emission tomography (FDG‐PET) has shown altered auditory pathway activity in tinnitus. However, the corresponding studies involved only small samples and analyses were restricted to the auditory cortex in most studies. Evidence is growing that also limbic, frontal, and parietal areas are involved in the pathophysiology of chronic tinnitus. These regions are considered to mediate perceptual, attentional, and emotional processes. Thus, the aim of the present study was the systematic evaluation of metabolic brain activity in a large sample of tinnitus patients. Ninety one patients with chronic tinnitus underwent FDG‐PET. The effects of tinnitus severity (assessed by a tinnitus questionnaire score), duration and laterality were evaluated with st... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5338163 Sat, 22 Oct 2011 04:00:00 +0100 5338163 http://www.medworm.com/index.php?rid=5338162&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21427 This study shows for the first time that patients with schizophrenia can learn volitional brain regulation by rtfMRI feedback training leading to changes in the perception of emotions and modulations of the brain network connectivity. These findings open the door for further studies of rtfMRI in severely ill psychiatric populations, and possible therapeutic applications. Hum Brain Mapp, 2011. © 2011 Wiley Periodicals, Inc. (Source: Human Brain Mapping) Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5338162 Sat, 22 Oct 2011 04:00:00 +0100 5338162 http://www.medworm.com/index.php?rid=5338161&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21429 AbstractWhen manipulating objects with both hands, the corpus callosum (CC) is of paramount importance for interhemispheric information exchange. Hence, CC damage results in impaired bimanual performance. Here, healthy young adults performed a complex bimanual dial rotation task with or without augmented visual feedback and according to five interhand frequency ratios (1:1, 1:3, 2:3, 3:1, 3:2). The relation between bimanual task performance and microstructural properties of seven CC subregions (i.e., prefrontal, premotor/supplementary motor, primary motor, primary sensory, occipital, parietal, and temporal) was studied by means of diffusion tensor imaging (DTI). Findings revealed that bimanual coordination deteriorated in the absence as compared to the presence of augmented visual feedback... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5338161 Sat, 22 Oct 2011 04:00:00 +0100 5338161 http://www.medworm.com/index.php?rid=5338160&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21430 AbstractPrevious studies have indicated that increasing working memory (WM) load can affect the attentional selection of signals originating from one object/location. Here we assessed whether WM load affects also the selection of multiple objects/locations (divided attention). Participants monitored either two object‐categories (vs. one category; object‐based divided attention) or two locations (vs. one location; space‐based divided attention) while maintaining in WM either a variable number of objects (object‐based WM load) or locations (space‐based WM load). Behavioural results showed that WM load affected attentional performance irrespective of divided or focused attention. However, fMRI results showed that the activity associated with object‐based divided attention increase... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5338160 Sat, 22 Oct 2011 04:00:00 +0100 5338160 http://www.medworm.com/index.php?rid=5338169&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21485 AbstractInducing and experiencing emotions about others' mental and physical circumstances is thought to involve self‐relevant processing and personal memories of similar experiences. The hippocampus is important for self‐referential processing during recall and prospection; however, its contributions during social emotions have not been systematically investigated. We use event‐related averaging and Granger causal connectivity mapping to investigate hippocampal contributions during the processing of varieties of admiration and compassion pertaining to protagonists' mental versus physical circumstances [admiration for virtue (AV) versus for skill; compassion for social/psychological pain (CSP) versus for physical pain]. Data were collected using a multistep emotion‐induction paradi... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5338169 Thu, 20 Oct 2011 04:00:00 +0100 5338169 http://www.medworm.com/index.php?rid=5338168&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21441 AbstractAutism spectrum disorder is a heterogeneous disorder of brain development with wide ranging cognitive deficits. Typically diagnosed before age 3, autism spectrum disorder is behaviorally defined but patients are thought to have protracted alterations in brain maturation. With longitudinal magnetic resonance imaging (MRI), we mapped an anomalous developmental trajectory of the brains of autistic compared with those of typically developing children and adolescents. Using tensor‐based morphometry, we created 3D maps visualizing regional tissue growth rates based on longitudinal brain MRI scans of 13 autistic and seven typically developing boys (mean age/interscan interval: autism 12.0 ± 2.3 years/2.9 ± 0.9 years; control 12.3 ± 2.4/2.8 ± 0.8). The typically developing boys demon... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5338168 Thu, 20 Oct 2011 04:00:00 +0100 5338168 http://www.medworm.com/index.php?rid=5325387&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21415 This study tests the hypothesis that white‐collar criminals have better executive functioning, enhanced information processing, and structural brain superiorities compared with offender controls. Using a case‐control design, executive functioning, orienting, and cortical thickness was assessed in 21 white‐collar criminals matched with 21 controls on age, gender, ethnicity, and general level of criminal offending. White‐collar criminals had significantly better executive functioning, increased electrodermal orienting, increased arousal, and increased cortical gray matter thickness in the ventromedial prefrontal cortex, inferior frontal gyrus, somatosensory cortex, and the temporal‐parietal junction compared with controls. Results, while initial, constitute the first findings on ne... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5325387 Tue, 18 Oct 2011 23:16:53 +0100 5325387 http://www.medworm.com/index.php?rid=5316897&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21423 AbstractMost neuroimaging studies on planning report bilateral activations of the dorsolateral prefrontal cortex (dlPFC). Recently, these concurrent activations of left and right dlPFC have been shown to double dissociate with different cognitive demands imposed by the planning task: Higher demands on the extraction of task‐relevant information led to stronger activation in left dlPFC, whereas higher demands on the integration of interdependent information into a coherent action sequence entailed stronger activation of right dlPFC. Here, we used continuous theta‐burst stimulation (cTBS) to investigate the supposed causal structure‐function mapping underlying this double dissociation. Two groups of healthy subjects (left‐lateralized stimulation, n = 26; right‐lateralized stimulati... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5316897 Sat, 15 Oct 2011 15:27:24 +0100 5316897 http://www.medworm.com/index.php?rid=5316900&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21411 AbstractNocturnal enuresis is a common developmental disorder in children, and primary nocturnal enuresis (PNE) is the dominant subtype. The main purpose of this study was to investigate brain functional abnormalities specifically related to motor response inhibition in children with PNE using fMRI in combination with a Go/NoGo task. Twenty‐two children with PNE and 22 healthy children, group‐matched for age and sex, took part in this experiment. Although no significant between‐group differences in task performance accuracy were observed, PNE patients showed significantly longer response times on average. There were several brain regions with reduced activation during motor response inhibition in children with PNE: the bilateral inferior frontal gyri, right superior and middle fronta... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5316900 Fri, 14 Oct 2011 04:00:00 +0100 5316900 http://www.medworm.com/index.php?rid=5316899&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21420 AbstractA large body of behavioural research has used the cued task‐switching paradigm to characterize the nature of trial‐by‐trial preparatory adjustments that enable fluent task implementation when demands on cognitive flexibility are high. This work reviews the growing number of fMRI studies on the same topic, mostly focusing on the central hypothesis that preparatory adjustments should be indicated by enhanced prefrontal and parietal BOLD activation in task switch when compared with task repeat trials under conditions that enable advance task preparation. The evaluation of this straight‐forward hypothesis reveals surprisingly heterogeneous results regarding both the precise localization and the very existence of switch‐related preparatory activation. Explanations for these in... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5316899 Fri, 14 Oct 2011 04:00:00 +0100 5316899 http://www.medworm.com/index.php?rid=5316898&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21421 AbstractRecent studies highlighted the great potential of newly established theta burst stimulation (TBS) protocols for non‐invasive human brain stimulation studies using transcranial magnetic stimulation (TMS). While intermittent TBS over the primary motor cortex was found to potentiate motor evoked potentials, continuous TBS led to profound attenuations. Although numerous studies investigated the impact of TBS on motor cortex function, yet, only few imaging studies focused on its effects in other brain areas. Particularly for the prefrontal cortex, it is unclear whether TBS has similar effects compared to application over motor areas. In the current study continuous TBS was applied to either the left or right dorsolateral prefrontal cortex in a sample of healthy subjects. Changes in pr... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5316898 Fri, 14 Oct 2011 04:00:00 +0100 5316898 http://www.medworm.com/index.php?rid=5316903&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21376 AbstractWe used functional magnetic resonance imaging (fMRI) to investigate brain processes underlying control of emotional responses towards a person in distress by cognitive social distance modulation. fMRI and peripheral physiological responses (startle response and electrodermal activity) were recorded from 24 women while they watched victim–offender scenes and modulated their social distance to the victim by cognitive reappraisal. We found that emotional responses, including startle eyeblink and amygdala responses, can effectively be modulated by social distance modulation. Furthermore, our data provide evidence that activity in the dorsomedial prefrontal cortex (dmPFC) and the anterior paracingulate cortex (aPCC), two brain regions that have previously been associated with brain pr... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5316903 Thu, 13 Oct 2011 04:00:00 +0100 5316903 http://www.medworm.com/index.php?rid=5316902&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21392 AbstractSomatoform disorder patients suffer from impaired emotion recognition and other emotional deficits. Emotional empathy refers to the understanding and sharing of emotions of others in social contexts. It is likely that the emotional deficits of somatoform disorder patients are linked to disturbed empathic abilities; however, little is known so far about empathic deficits of somatoform patients and the underlying neural mechanisms. We used fMRI and an empathy paradigm to investigate 20 somatoform disorder patients and 20 healthy controls. The empathy paradigm contained facial pictures expressing anger, joy, disgust, and a neutral emotional state; a control condition contained unrecognizable stimuli. In addition, questionnaires testing for somatization, alexithymia, depression, empath... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5316902 Thu, 13 Oct 2011 04:00:00 +0100 5316902 http://www.medworm.com/index.php?rid=5316901&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21396 We examined cognitive processes related to recognition of objects, their relations, and the patterns they form by using the game of chess. Chess enables us to compare experts with novices and thus gain insight in the nature of development of recognition skills. Eye movement recordings showed that experts were generally faster than novices on a task that required enumeration of relations between chess objects because their extensive knowledge enabled them to immediately focus on the objects of interest. The advantage was less pronounced on random positions where the location of chess objects, and thus typical relations between them, was randomized. Neuroimaging data related experts' superior performance to the areas along the dorsal stream—bilateral posterior temporal areas and left infer... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5316901 Thu, 13 Oct 2011 04:00:00 +0100 5316901 http://www.medworm.com/index.php?rid=5287508&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21326 AbstractA number of magnetic resonance imaging (MRI) studies have revealed morphological cortical asymmetry in the normal human brain, and reduction or inversion of such hemispheric asymmetry has been reported in schizophrenia. On the other hand, diffusion tensor imaging (DTI) studies have reported inconsistent findings concerning abnormal asymmetry of white matter integrity in schizophrenia. Our aim was to confirm whether there is reduced or inverted asymmetry of white matter integrity in the whole brain in schizophrenia. For this study, 26 right‐handed schizophrenia patients, and 32 matched healthy control subjects were investigated. Voxelwise analysis of DTI data was performed using the tract‐based spatial statistics. The fractional anisotropy (FA) images were normalized and project... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5287508 Wed, 05 Oct 2011 04:00:00 +0100 5287508 http://www.medworm.com/index.php?rid=5287507&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21365 AbstractAccording to an embodied view of language comprehension, language concepts are grounded in our perceptual systems. Evidence for the idea that concepts are grounded in areas involved in action and perception comes from both behavioral and neuroimaging studies (Glenberg [1997]: Behav Brain Sci 20:1‐55; Barsalou [1999]: Behav Brain Sci 22:577‐660; Pulvermueller [1999]: Behav Brain Sci 22:253‐336; Barsalou et al. [2003]: Trends Cogn Sci 7:84‐91). However, the results from several studies indicate that the activation of information in perception and action areas is not a purely automatic process (Raposo et al. [2009]: Neuropsychologia 47:388‐396; Rueschemeyer et al. [2007]: J Cogn Neurosci 19:855‐865). These findings suggest that embodied representations are flexible. In the... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5287507 Wed, 05 Oct 2011 04:00:00 +0100 5287507 http://www.medworm.com/index.php?rid=5287506&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21399 This study investigated the preparatory control of motor inhibition and motor execution using a stop signal task (SST) and functional magnetic resonance imaging (fMRI). In the SST, a frequent “go” signal triggered a prepotent response and a less frequent “stop” signal prompted the inhibition of this response. Preparatory control of motor inhibition and execution in the stop signal trials were examined by contrasting brain activation between stop success and stop error trials during the fore‐period, in which participants prepared to respond to go or to stop. Results from 91 healthy adults showed greater activation in the right prefrontal cortex and inferior parietal lobule during preparatory motor inhibition. Preparatory motor execution activated bilateral putamen, primary motor c... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5287506 Wed, 05 Oct 2011 04:00:00 +0100 5287506 http://www.medworm.com/index.php?rid=5287505&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21405 AbstractDespite intensive study, the role of the dorsal medial frontal cortex (dMFC) in error monitoring and conflict processing remains actively debated. The current experiment manipulated conflict type (stimulus conflict only or stimulus and response selection conflict) and utilized a novel modeling approach to isolate error and conflict variance during a multimodal numeric Stroop task. Specifically, hemodynamic response functions resulting from two statistical models that either included or isolated variance arising from relatively few error trials were directly contrasted. Twenty‐four participants completed the task while undergoing event‐related functional magnetic resonance imaging on a 1.5‐Tesla scanner. Response times monotonically increased based on the presence of pure stim... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5287505 Wed, 05 Oct 2011 04:00:00 +0100 5287505 http://www.medworm.com/index.php?rid=5287504&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21402 AbstractPrevious imaging studies assessing the relationship between white matter (WM) damage and matter (GM) atrophy have raised the concern that Multiple Sclerosis (MS) WM lesions may affect measures of GM volume by inducing voxel misclassification during intensity‐based tissue segmentation. Here, we quantified this misclassification error in simulated and real MS brains using a lesion‐filling method. Using this method, we also corrected GM measures in patients before comparing them with controls in order to assess the impact of this lesion‐induced misclassification error in clinical studies. We found that higher WM lesion volumes artificially reduced total GM volumes. In patients, this effect was about 72% of that predicted by simulation. Misclassified voxels were located at the GM... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5287504 Wed, 05 Oct 2011 04:00:00 +0100 5287504 http://www.medworm.com/index.php?rid=5287503&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21428 AbstractUsing functional magnetic resonance imaging, we show that a distributed fronto‐parietal visuomotor integration network is recruited to overcome automatic responses to both biological and nonbiological cues. Activity levels in these areas are similar for both cue types. The functional connectivity of this network, however, reveals differential coupling with thalamus and precuneus (biological cues) and extrastriate cortex (nonbiological cues). This suggests that a set of cortical areas equally activated in two tasks may accomplish task goals differently depending on their network interactions. This supports models of brain organization that emphasize efficient coding through changing patterns of integration between regions of specialized function. Hum Brain Mapp, 2011. © 2011 Wile... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5287503 Sat, 01 Oct 2011 04:00:00 +0100 5287503 http://www.medworm.com/index.php?rid=5252109&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21384 In this study, we examined how the pattern of activation in core reading regions changes as the ability to read fluently is manipulated through reading speed. We evaluated 13 right‐handed adults with a novel fMRI task assessing fluent sentence reading and lower‐order letter reading at each participant's normal fluent reading speed, as well as constrained (slowed) and accelerated reading speeds. Comparing fluent reading conditions with rest revealed regions including bilateral occipito‐fusiform, left middle temporal, and inferior frontal gyral clusters across reading speeds. The selectivity of these regions' responses to fluent sentence reading was shown by comparison with the letter reading task. Region of interest analyses showed that at constrained and accelerated speeds these regi... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5252109 Mon, 26 Sep 2011 01:23:46 +0100 5252109 http://www.medworm.com/index.php?rid=5252115&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21403 In conclusion, the high temporal sampling rates achievable with InI permit significant reductions in physiological noise using standard temporal filtering techniques that result in significant improvements in hemodynamic response estimation. Hum Brain Mapp, 2011. © 2011 Wiley‐Liss, Inc. (Source: Human Brain Mapping) Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5252115 Fri, 23 Sep 2011 04:00:00 +0100 5252115 http://www.medworm.com/index.php?rid=5252114&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21278 AbstractThe brain seeks to combine related inputs from different senses (e.g., hearing and vision), via multisensory integration. Temporal information can indicate whether stimuli in different senses are related or not. A recent human fMRI study (Noesselt et al. [2007]: J Neurosci 27:11431–11441) used auditory and visual trains of beeps and flashes with erratic timing, manipulating whether auditory and visual trains were synchronous or unrelated in temporal pattern. A region of superior temporal sulcus (STS) showed higher BOLD signal for the synchronous condition. But this could not be related to performance, and it remained unclear if the erratic, unpredictable nature of the stimulus trains was important. Here we compared synchronous audiovisual trains to asynchronous trains, while usin... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5252114 Fri, 23 Sep 2011 04:00:00 +0100 5252114 http://www.medworm.com/index.php?rid=5252113&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21424 In this study we investigated functional connectivity changes in MS using resting‐state magnetoencephalography (MEG). Data from 34 MS patients and 28 age and gender‐matched controls was assessed using synchronization likelihood (SL) as a measure of functional interaction strength between brain regions, and graph analysis to characterize topological patterns of connectivity changes. Cognition was assessed using extensive neuropsychological evaluation. Structural measures included brain and lesion volumes, using MRI. Results show SL increases in MS patients in theta, lower alpha and beta bands, with decreases in the upper alpha band. Graph analysis revealed a more regular topology in the lower alpha band in patients, indicated by an increased path length (λ) and clustering coefficient (... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5252113 Fri, 23 Sep 2011 04:00:00 +0100 5252113 http://www.medworm.com/index.php?rid=5252112&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21422 AbstractThe neural substrate underlying cognitive impairments after chemotherapy is largely unknown. Here, we investigated very late (>9 years) effects of adjuvant high‐dose chemotherapy on brain white and gray matter in primary breast cancer survivors (n = 17) with multimodal magnetic resonance imaging (MRI). A group of breast cancer survivors who did not receive chemotherapy was scanned for comparison (n = 15). Neuropsychological tests demonstrated cognitive impairments in the chemotherapy group. Diffusion tensor imaging (DTI) with tract‐based spatial statistics showed that chemotherapy was associated with focal changes in DTI values indicative for reduced white matter integrity. Single voxel proton MR spectroscopy (1H‐MRS) in the left centrum semiovale (white matter) showed a r... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5252112 Fri, 23 Sep 2011 04:00:00 +0100 5252112 http://www.medworm.com/index.php?rid=5252111&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21413 AbstractViewing emotional pictures is associated with heightened perception and attention, indexed by a relative increase in visual cortical activity. Visual cortical modulation by emotion is hypothesized to reflect re‐entrant connectivity originating in higher‐order cortical and/or limbic structures. The present study used dense‐array electroencephalography and individual brain anatomy to investigate functional coupling between the visual cortex and other cortical areas during affective picture viewing. Participants viewed pleasant, neutral, and unpleasant pictures that flickered at a rate of 10 Hz to evoke steady‐state visual evoked potentials (ssVEPs) in the EEG. The spectral power of ssVEPs was quantified using Fourier transform, and cortical sources were estimated using beamfo... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5252111 Fri, 23 Sep 2011 04:00:00 +0100 5252111 http://www.medworm.com/index.php?rid=5252110&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21412 We examined how white matter structure was associated with performance on tests of two cognitive domains, executive functioning (EF) and processing speed (PS), and how patterns of regional associations were modified by BP and WMSA. Multiple linear regression and structural equation models demonstrated associations between tissue structure, EF and PS in frontal, temporal, parietal, and occipital white matter regions. Radial diffusivity was more prominently associated with performance than axial diffusivity. BP only minimally influenced the relationship between white matter integrity, EF and PS. However, WMSA volume had a major impact on neurocognitive associations. This suggests that, although BP and WMSA are causally related, these differential metrics of vascular health may act via indepe... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5252110 Fri, 23 Sep 2011 04:00:00 +0100 5252110 http://www.medworm.com/index.php?rid=5240007&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21409 AbstractStress has a powerful impact on memory. Corticosteroids, released in response to stress, are thought to mediate, at least in part, these effects by affecting neuronal plasticity in brain regions involved in memory formation, including the hippocampus and prefrontal cortex. Animal studies have delineated aspects of the underlying physiological mechanisms, revealing rapid, nongenomic effects facilitating synaptic plasticity, followed several hours later by a gene‐mediated suppression of this plasticity. Here, we tested the hypothesis that corticosteroids would also rapidly upregulate and slowly downregulate brain regions critical for episodic memory formation in humans. To target rapid and slow effects of corticosteroids on neural processing associated with memory formation, we inv... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5240007 Thu, 22 Sep 2011 14:05:46 +0100 5240007 http://www.medworm.com/index.php?rid=5240010&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21394 AbstractEstimating cortical current distributions from electroencephalographic (EEG) or magnetoencephalographic data is a difficult inverse problem whose solution can be improved by the addition of priors on the associated neural responses. In the context of visual activation studies, we propose a new approach that uses a functional area constrained estimator (FACE) to increase the accuracy of the reconstructions. It derives the source correlation matrix from a segmentation of the cortex into areas defined by retinotopic maps of the visual field or by functional localizers obtained independently by fMRI. These areas are computed once for each individual subject and the associated estimators can therefore be reused for any new study on the same participant. The resulting FACE reconstruction... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5240010 Wed, 21 Sep 2011 04:00:00 +0100 5240010 http://www.medworm.com/index.php?rid=5240009&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21398 AbstractThe ability to resist immediate rewards is crucial for lifetime success and individual well‐being. Using functional magnetic resonance imaging, we assessed the association between trait impulsivity and the neural underpinnings of the ability to control immediate reward desiring. Low and high extreme impulsivity groups were compared with regard to their behavioral performance and brain activation in situations, in which they had to forego immediate rewards with varying value to achieve a superordinate long‐term goal. We found that highly impulsive (HI) individuals, who successfully compensated for their lack in behavioral self‐control, engaged two complementary brain mechanisms when choosing actions in favor of a long‐term goal, but at the expense of an immediate reward. Fir... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5240009 Wed, 21 Sep 2011 04:00:00 +0100 5240009 http://www.medworm.com/index.php?rid=5240008&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21400 AbstractPrevious anatomical studies in monkeys have shown that forelimb motor representation is located caudal to hindlimb representation within the dorso‐rostral dentate nucleus. Here we investigate human dentate nucleus motor somatotopy by means of ultra‐highfield (7 T) functional magnetic brain imaging (fMRI). Twenty five young healthy males participated in the study. Simple finger and foot movement tasks were performed to identify dentate nucleus motor areas. Recently developed normalization procedures for group analyses were used for the cerebellar cortex and the cerebellar dentate nucleus. Cortical activations were in good accordance with the known somatotopy of the human cerebellar cortex. Dentate nucleus activations following motor tasks were found in particular in the ipsilate... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5240008 Wed, 21 Sep 2011 04:00:00 +0100 5240008 http://www.medworm.com/index.php?rid=5240019&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21373 AbstractThere has been much debate recently over the functional role played by the planum temporale (PT) within the context of the dorsal auditory processing stream. Some studies indicate that regions in the PT support spatial hearing and other auditory functions, whereas others demonstrate sensory‐motor response properties. This multifunctionality has led to the claim that the PT is performing a common computational pattern matching operation, then routing the signals (spatial, object, sensory‐motor) into an appropriate processing stream. An alternative possibility is that the PT is functionally subdivided with separate regions supporting various functions. We assess this possibility using a within subject fMRI block design. DTI data were also collected to examine connectivity. There ... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5240019 Tue, 20 Sep 2011 04:00:00 +0100 5240019 http://www.medworm.com/index.php?rid=5240018&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21385 AbstractCurrent theories suggest that disrupting cortical information integration may account for the mechanism of general anesthesia in suppressing consciousness. Human cognitive operations take place in hierarchically structured neural organizations in the brain. The process of low‐order neural representation of sensory stimuli becoming integrated in high‐order cortices is also known as cognitive binding. Combining neuroimaging, cognitive neuroscience, and anesthetic manipulation, we examined how cognitive networks involved in auditory verbal memory are maintained in wakefulness, disrupted in propofol‐induced deep sedation, and re‐established in recovery. Inspired by the notion of cognitive binding, an functional magnetic resonance imaging‐guided connectivity analysis was utili... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5240018 Tue, 20 Sep 2011 04:00:00 +0100 5240018 http://www.medworm.com/index.php?rid=5240017&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21389 AbstractDistinct thalamic nuclei, like the mediodorsal (MD) nucleus and the centromedian/parafascicular complex (CM/Pf), are embedded in different basal ganglia—thalamocortical loops, which were shown to integrate cognitive and emotional aspects of human behavior. Despite well described connections on a microscopic scale, derived from tracing studies in animals, little is known about the intrinsic anatomical connections of these nuclei in humans. This lack of knowledge limits not only interpretation of functional imaging studies but also estimation of direct effects of deep brain stimulation which treats diseases as different as epilepsy or major depression. Therefore, non‐invasive diffusion tensor imaging (DTI) studies are key to analyzing connectivity patterns and elaborate approache... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5240017 Tue, 20 Sep 2011 04:00:00 +0100 5240017 http://www.medworm.com/index.php?rid=5240016&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21391 AbstractBehavioral and function magnetic resonance imagery (fMRI) data were combined to infer the mental states of students as they interacted with an intelligent tutoring system. Sixteen children interacted with a computer tutor for solving linear equations over a six‐day period (Days 0–5), with Days 1 and 5 occurring in an fMRI scanner. Hidden Markov model algorithms combined a model of student behavior with multi‐voxel imaging pattern data to predict the mental states of students. We separately assessed the algorithms' ability to predict which step in a problem‐solving sequence was performed and whether the step was performed correctly. For Day 1, the data patterns of other students were used to predict the mental states of a target student. These predictions were improved on Da... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5240016 Tue, 20 Sep 2011 04:00:00 +0100 5240016 http://www.medworm.com/index.php?rid=5240015&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21393 AbstractPrevious brain imaging studies identified the neural networks underlying free choice of self‐initiated actions. In contrast, the neural mechanisms underlying free choice of external objects remain to be elucidated. In this event‐related functional magnetic resonance imaging study, participants had to choose one out of two different single‐colored target squares presented at two of three possible locations. In 50% of the trials the choice was either free or specified, which was indicated by a preceding cue. In order to disentangle processes associated with object choice from those related to motor responses, object‐response mapping was orthogonally varied. Processes related to the freedom of choice were isolated by means of an adaptive algorithm: based on the subjects indivi... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5240015 Tue, 20 Sep 2011 04:00:00 +0100 5240015 http://www.medworm.com/index.php?rid=5240014&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21395 AbstractCross‐modal processing enables the utilization of information received via different sensory organs to facilitate more complicated human actions. We used functional MRI on early‐blind individuals to study the neural processes associated with cross auditory‐spatial learning. The auditory signals, converted from echoes of ultrasonic signals emitted from a navigation device, were novel to the participants. The subjects were trained repeatedly for 4 weeks in associating the auditory signals with different distances. Subjects' blood‐oxygenation‐level‐dependent responses were captured at baseline and after training using a sound‐to‐distance judgment task. Whole‐brain analyses indicated that the task used in the study involved auditory discrimination as well as spatial l... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5240014 Tue, 20 Sep 2011 04:00:00 +0100 5240014 http://www.medworm.com/index.php?rid=5240013&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21404 AbstractHistological studies have shown a relatively high iron concentration in the subthalamic nucleus (STN). T2‐ and T2*‐weighted sequences have previously been used to visualize the STN in vivo. The phase information of gradient‐echo images reflects the magnetic tissue properties more directly, e.g., iron is more paramagnetic than water. Unfortunately, phase images suffer from non‐local effects and orientation dependency. The goal of this study is to delineate the STN more precisely using susceptibility maps, calculated from phase images, which directly index magnetic tissue properties while removing the non‐local effects and orientation dependency. Use of 7T MRI enables high spatial resolution with good signal to noise ratio (SNR). Eight healthy subjects were scanned at 7T us... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5240013 Tue, 20 Sep 2011 04:00:00 +0100 5240013 http://www.medworm.com/index.php?rid=5240012&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21406 AbstractRegions of the fusiform gyrus (FG) respond preferentially to faces over other classes of visual stimuli. It remains unclear whether emotional face information modulates FG activity. In the present study, whole‐head magnetoencephalography (MEG) was obtained from fifteen healthy adults who viewed emotionally expressive faces and made button responses based upon emotion (explicit condition) or age (implicit condition). Dipole source modeling produced source waveforms for left and right primary visual and left and right fusiform areas. Stronger left FG activity (M170) to fearful than happy or neutral faces was observed only in the explicit task, suggesting that directed attention to the emotional content of faces facilitates observation of M170 valence modulation. A strong associatio... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5240012 Tue, 20 Sep 2011 04:00:00 +0100 5240012 http://www.medworm.com/index.php?rid=5240011&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21397 AbstractTo examine how musical expertise tunes the brain to subtle metric anomalies in an ecological musical context, we presented piano compositions ending on standard and deviant cadences (endings) to expert pianists and musical laymen, while high‐density EEG was recorded. Temporal expectancies were manipulated by substituting standard “masculine” cadences at metrically strong positions with deviant, metrically unaccented, “feminine” cadences. Experts detected metrically deviant cadences better than laymen. Analyses of event‐related potentials demonstrated that an early P3a‐like component (∼ 150–300 ms), elicited by musical closure, was significantly enhanced at frontal and parietal electrodes in response to deviant endings in experts, whereas a reduced response to devi... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5240011 Tue, 20 Sep 2011 04:00:00 +0100 5240011 http://www.medworm.com/index.php?rid=5228126&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21407 AbstractParieto‐frontal network is essential for sensorimotor integration in various complex behaviors, and its disruption is associated with pathophysiology of apraxia and visuo‐spatial disorders. Despite advances in knowledge regarding specialized cortical areas for various sensorimotor transformations, little is known about the underlying cortico‐cortical connectivity in humans. We investigated inter‐areal connections of the lateral parieto‐frontal network in vivo by means of cortico‐cortical evoked potentials (CCEPs). Six patients with epilepsy and one with brain tumor were studied. With the use of subdural electrodes implanted for presurgical evaluation, network configuration was investigated by tracking the connections from the parietal stimulus site to the frontal site w... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5228126 Mon, 19 Sep 2011 04:54:27 +0100 5228126 http://www.medworm.com/index.php?rid=5228135&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21379 AbstractWhile schizophrenia is frequently characterized as a disorder of disturbed functional connectivity, the causes and pathophysiological origins of such disturbances remain unclear. The aim of this study was to better elucidate the mechanistic causes of abnormal functional connectivity in schizophrenia, measured as the extent of temporal correlation between endogenous fluctuations recorded at anatomically discrete brain regions during resting‐state functional MRI. An approach was developed to perform whole‐brain connectivity mapping at the resolution of individual pairs of voxels, without the need for arbitrary parcellation of the cerebrum. Between‐group connectivity reductions in 12 people diagnosed with schizophrenia and 15 age‐, IQ‐, and gender‐matched healthy volunteer... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5228135 Fri, 16 Sep 2011 04:00:00 +0100 5228135 http://www.medworm.com/index.php?rid=5228134&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21381 AbstractThe hallucinogenic brew Ayahuasca, a rich source of serotonergic agonists and reuptake inhibitors, has been used for ages by Amazonian populations during religious ceremonies. Among all perceptual changes induced by Ayahuasca, the most remarkable are vivid “seeings.” During such seeings, users report potent imagery. Using functional magnetic resonance imaging during a closed‐eyes imagery task, we found that Ayahuasca produces a robust increase in the activation of several occipital, temporal, and frontal areas. In the primary visual area, the effect was comparable in magnitude to the activation levels of natural image with the eyes open. Importantly, this effect was specifically correlated with the occurrence of individual perceptual changes measured by psychiatric scales. Th... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5228134 Fri, 16 Sep 2011 04:00:00 +0100 5228134 http://www.medworm.com/index.php?rid=5228133&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21382 AbstractImpulsivity is a trait shared by many psychiatric disorders and therefore a suitable intermediate phenotype for their underlying biological mechanisms. One of the molecular determinants involved is the NOS1 ex1f‐VNTR, whose short variants are associated with a variety of impulsive behaviors. Fifty‐six healthy controls were stratified into homozygous long (LL) (30 probands) and short (SS) (26 probands) allele groups. Subjects completed a combined stop‐signal go/nogo task, while the oxygenation in the prefrontal cortex was measured with functional near‐infrared spectroscopy. Electromyography was recorded to control for differences in muscle activity in the two inhibition tasks. Two questionnaires on impulsive traits were completed. Differences between the two tasks are shown ... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5228133 Fri, 16 Sep 2011 04:00:00 +0100 5228133 http://www.medworm.com/index.php?rid=5228132&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21383 AbstractConverging evidence from neuroimaging as well as lesion and transcranial magnetic stimulation (TMS) studies has been obtained for the involvement of right ventral posterior parietal cortex (PPC) in exogenous orienting. However, the contribution of dorsal PPC to attentional orienting, particularly endogenous orienting, is still under debate. In an informative peripheral cueing paradigm, in which the exogenous and endogenous orienting can be studied in relative isolation within a single task, we applied TMS over sub‐regions of dorsal PPC to explore their possible distinct involvement in exogenous and endogenous processes. We found that disruption of the left posterior intraparietal sulcus (pIPS) weakened the attentional effects of endogenous orienting, but did not affect exogenous ... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5228132 Fri, 16 Sep 2011 04:00:00 +0100 5228132 http://www.medworm.com/index.php?rid=5228131&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21390 AbstractBehavioral reactions to sensory stimuli during sleep are scarce despite preservation of sizeable cortical responses. To further understand such dissociation, we recorded intracortical field potentials to painful laser pulses in humans during waking and all‐night sleep. Recordings were obtained from the three cortical structures receiving 95% of the spinothalamic cortical input in primates, namely the parietal operculum, posterior insula, and mid‐anterior cingulate cortex. The dynamics of responses during sleep differed among cortical sites. In sleep Stage 2, evoked potential amplitudes were similarly attenuated relative to waking in all three cortical regions. During paradoxical, or rapid eye movements (REM), sleep, opercular and insular potentials remained stable in comparison... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5228131 Fri, 16 Sep 2011 04:00:00 +0100 5228131 http://www.medworm.com/index.php?rid=5228130&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21360 Conclusions: These findings suggest that vulnerability to psychosis was associated with neurofunctional alterations in fronto‐temporo‐parietal networks in a WM task. Neurofunctional differences within the ARMS were related to different duration of the prodromal state and resilience factors. Hum Brain Mapp, 2011. © 2011 Wiley‐Liss, Inc. (Source: Human Brain Mapping) Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5228130 Fri, 16 Sep 2011 04:00:00 +0100 5228130 http://www.medworm.com/index.php?rid=5228129&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21380 AbstractTranscranial direct current stimulation (tDCS) is a noninvasive brain stimulation technique that has been shown to alter cortical excitability and activity via application of weak direct currents. Beyond intracortical effects, functional imaging as well as behavioral studies are suggesting additional tDCS‐driven alterations of subcortical areas, however, direct evidence for such effects is scarce. We aimed to investigate the impact of tDCS on cortico‐subcortical functional networks by seed functional connectivity analysis of different striatal and thalamic regions to prove tDCS‐induced alterations of the cortico‐striato‐thalamic circuit. fMRI resting state data sets were acquired immediately before and after 10 min of bipolar tDCS during rest, with the anode/cathode place... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5228129 Fri, 16 Sep 2011 04:00:00 +0100 5228129 http://www.medworm.com/index.php?rid=5228128&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21372 This study is the first to investigate fiber integrity in the dorsal/ventral frontal parts of the callosal tractography in unmedicated OCD patients. Using a more quantitative method in terms of functional and regional specificity than previous studies, we report abnormalities in interhemispheric connectivity of both dorsal and ventral networks in the pathophysiology of OCD. Hum Brain Mapp, 2011. © 2011 Wiley‐Liss, Inc. (Source: Human Brain Mapping) Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5228128 Fri, 16 Sep 2011 04:00:00 +0100 5228128 http://www.medworm.com/index.php?rid=5228127&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21332 AbstractEstimating the interregional structural connections of the brain via diffusion tractography is a complex procedure and the parameters chosen can affect the outcome of the connectivity matrix. Here, we investigated the influence of different connection reconstruction methods on brain connectivity networks. Specifically, we applied three connection reconstruction methods to the same set of diffusion MRI data, initiating tracking from deep white matter (method #1, M1), from the gray matter/white matter interface (M2), and from the gray/white matter interface with thresholded tract volume rather than the connection probability as the connectivity index (M3). Small‐world properties, hub identification, and hemispheric asymmetry in connectivity patterns were then calculated and compare... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5228127 Fri, 16 Sep 2011 04:00:00 +0100 5228127 http://www.medworm.com/index.php?rid=5228138&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21303 AbstractIndependent component analysis (ICA) of electroencephalographic (EEG) and magnetoencephalographic (MEG) data is usually performed over the temporal dimension: each channel is one row of the data matrix, and a linear transformation maximizing the independence of component time courses is sought. In functional magnetic resonance imaging (fMRI), by contrast, most studies use spatial ICA: each time point constitutes a row of the data matrix, and independence of the spatial patterns is maximized. Here, we show the utility of spatial ICA in characterizing oscillatory neuromagnetic signals. We project the sensor data into cortical space using a standard minimum‐norm estimate and apply a sparsifying transform to focus on oscillatory signals. The resulting method, spatial Fourier‐ICA, p... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5228138 Tue, 13 Sep 2011 04:00:00 +0100 5228138 http://www.medworm.com/index.php?rid=5228137&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21334 AbstractThere is consistent evidence that brain volume changes in early and late life. Most longitudinal studies usually only span a few years and include a limited number of participants. In this review, we integrate findings from 56 longitudinal magnetic resonance imaging (MRI) studies on whole brain volume change in healthy individuals. The individual longitudinal MRI studies describe only the development in a limited age range. In total, 2,211 participants were included. Age at first measurement varied between 4 and 88 years of age. The studies included in this review were performed using a large range of methods (e.g., different scanner protocols and different acquisition parameters). We applied a weighted regression analysis to estimate the age dependency of the rate of relative annu... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5228137 Tue, 13 Sep 2011 04:00:00 +0100 5228137 http://www.medworm.com/index.php?rid=5228136&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21343 AbstractTrans‐synaptic degeneration could exacerbate neurodegeneration in multiple sclerosis (MS). We aimed to assess whether anterograde trans‐synaptic degeneration could be identified in the primary visual pathway in vivo. Diffusion tensor imaging (DTI) was used to assess the optic radiations in 15 patients with previous optic nerve inflammation and 9 healthy volunteers. A probabilistic atlas of the optic radiations was created from healthy diffusion tractography data. Lengthwise profiles for DTI parameters (axial [λ||], radial [λ⟂] and mean diffusivity [MD], fractional anisotropy [FA] and the angle of deviation of the principal eigenvector [α]) were analyzed for patients and controls. Patients also underwent multifocal visual evoked potential (mfVEP) assessments to characterize... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5228136 Tue, 13 Sep 2011 04:00:00 +0100 5228136 http://www.medworm.com/index.php?rid=5197608&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21359 AbstractMemory deficits are highly prevalent in multiple sclerosis (MS). As the hippocampus is crucial to memory processing, a functional magnetic resonance imaging (fMRI) task was used to investigate changes in hippocampal function in MS patients with and without cognitive decline. Fifty patients with MS, (34 cognitively preserved (CP) and 16 cognitively impaired (CI)) and 30 healthy controls completed an episodic memory fMRI task (encoding and retrieval) that was used to specifically activate the hippocampus. During encoding of correctly remembered items, increased brain activation was seen in the parahippocampal areas bilaterally and in the left anterior cingulate gyrus in the CP patients compared to the controls (unclustered, Z ≥ 3.1, P ≤ 0.001). No brain areas showed less activati... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5197608 Mon, 05 Sep 2011 23:00:00 +0100 5197608 http://www.medworm.com/index.php?rid=5197607&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21361 In this study, we test how this network responds to form and motion cues when observing natural human motion compared to rigid robotic‐like motion across two independent functional neuroimaging experiments. In Experiment 1, we report the surprising finding that premotor, parietal, occipitotemporal regions respond more robustly to rigid, robot‐like motion than natural human motion. In Experiment 2, we replicate and extend this finding by demonstrating that the same pattern of results emerges whether the agent is a human or a robot, which suggests the preferential response to robot‐like motion is independent of the agent's form. These data challenge previous ideas about AON function by demonstrating that the core nodes of this network can be flexibly engaged by novel, unfamiliar action... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5197607 Mon, 05 Sep 2011 23:00:00 +0100 5197607 http://www.medworm.com/index.php?rid=5197606&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21364 AbstractEvidence for an anterior‐posterior gradient of age‐related volume reduction along the hippocampal longitudinal axis has been reported in normal aging, but functional changes have yet to be systematically investigated. The current study applied an advanced brain mapping technique, large deformation diffeomorphic metric mapping (LDDMM), automatically delineating the hippocampus into the anterior and posterior segments based on anatomical landmarks. We studied this anterior‐posterior gradient in terms of structural and functional MRI in 66 participants aged from 19 to 79 years. The results showed age‐related structural volume reduction in both anterior and posterior hippocampi, with greater tendency for anterior decrease. FMRI task contrasts that robustly activated the anterio... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5197606 Mon, 05 Sep 2011 23:00:00 +0100 5197606 http://www.medworm.com/index.php?rid=5197605&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21374 AbstractThe aim of this large‐sample cross‐sectional voxel‐based morphometry (VBM) study of anatomical brain data was to investigate linear and nonlinear age‐related trajectories of grey matter volume in the human brain during the adult lifespan. To date, there are only a few structural brain studies investigating local nonlinear aspects at the voxel level, i.e., without using anatomical ROIs as a priori hypothesis. Therefore, we analyzed 547 T1‐weighted MR images of healthy adult brains with an age range of 19 to 86 years, including 161 scans of subjects with ages 60 and older. We found that the gray matter volume in some regions did not linearly decrease over time, but rather exhibited a delayed decline. Nonlinear age trajectories were observed in the medial temporal lobe regio... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5197605 Mon, 05 Sep 2011 23:00:00 +0100 5197605 http://www.medworm.com/index.php?rid=5197604&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21377 AbstractThe aim of this event‐related fMRI study was to investigate the cortical networks involved in case processing, an operation that is crucial to language comprehension yet whose neural underpinnings are not well‐understood. What is the relationship of these networks to those that serve other aspects of syntactic and semantic processing? Participants read Basque sentences that contained case violations, number agreement violations or semantic anomalies, or that were both syntactically and semantically correct. Case violations elicited activity increases, compared to correct control sentences, in a set of parietal regions including the posterior cingulate, the precuneus, and the left and right inferior parietal lobules. Number agreement violations also elicited activity increases i... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5197604 Mon, 05 Sep 2011 23:00:00 +0100 5197604 http://www.medworm.com/index.php?rid=5197603&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21378 We examined the relationship between global and regional gray matter (GM) volumes, sulcal indices, and thickness measures derived from the previous methods as well as their association with cognitive performance, age, severity of motor symptoms, and disease stage. VBM analyses showed GM volume reductions in the left temporal gyrus in patients compared with controls. Cortical folding measures revealed significant decreases in the left frontal and right collateral sulci in patients. Finally, analysis of cortical thickness showed widespread cortical thinning in right lateral occipital, parietal and left temporal, frontal, and premotor regions. We found that, in patients, all global anatomical measures correlated with age, while GM volume and cortical thickness significantly correlated with di... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5197603 Mon, 05 Sep 2011 23:00:00 +0100 5197603 http://www.medworm.com/index.php?rid=5197602&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21375 AbstractThe article to which this erratum refers was published in Hum Brain Mapp 2011, DOI: 10.1002/hbm.21013. © 2011 Wiley‐Liss, Inc. (Source: Human Brain Mapping) Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5197602 Wed, 31 Aug 2011 23:00:00 +0100 5197602 http://www.medworm.com/index.php?rid=5185623&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21344 AbstractMR‐based measurements of brain volumes may be affected by the presence of white matter (WM) lesions. Here, we assessed how and to what extent this may happen for WM lesions of various sizes and intensities. After inserting WM lesions of different sizes and intensities into T1‐W brain images of healthy subjects, we assessed the effect on two widely used automatic methods for brain volume measurement such as SIENAX (segmentation‐based) and SIENA (registration‐based). To explore the relevance of partial volume (PV) estimation, we performed the experiments with two different PV models, implemented by the same segmentation algorithm (FAST) of SIENAX and SIENA. Finally, we tested potential solutions to this issue. The presence of WM lesions did not bias measurements for registrat... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5185623 Wed, 31 Aug 2011 23:00:00 +0100 5185623 http://www.medworm.com/index.php?rid=5185624&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21341 AbstractRecurrent anticipation of ominous events is central to obsessions, the core symptom of obsessive‐compulsive disorder (OCD), yet the neural basis of intrinsic anticipatory processing in OCD is unknown. We studied nonmedicated adults with OCD and case matched healthy controls in a visual‐spatial working memory task with distractor. Magnetoencephalography was used to examine the medial cortex activity during anticipation of to‐be‐inhibited distractors and to‐be‐facilitated retrieval stimuli. In OCD anticipatory activation to distractors was abnormally reduced within the posterior cingulate and fusiform gyrus compared to prominent activation in controls. Conversely, OCD subjects displayed significantly increased activation to retrieval stimuli within the anterior cingulate ... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5185624 Tue, 30 Aug 2011 23:00:00 +0100 5185624 http://www.medworm.com/index.php?rid=5176526&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21388 AbstractThe benefits of locally adaptive statistical methods for fMRI research have been shown in recent years, as these methods are more proficient in detecting brain activations in a noisy environment. One such method is local canonical correlation analysis (CCA), which investigates a group of neighboring voxels instead of looking at the single voxel time course. The value of a suitable test statistic is used as a measure of activation. It is customary to assign the value to the center voxel for convenience. The method without constraints is prone to artifacts, especially in a region of localized strong activation. To compensate for these deficiencies, the impact of different spatial constraints in CCA on sensitivity and specificity are investigated. The ability of constrained CCA (cCCA)... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5176526 Tue, 30 Aug 2011 17:51:53 +0100 5176526 http://www.medworm.com/index.php?rid=5176533&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21342 Conclusions: These findings suggest that the ARMS and prodromal phase of psychosis are characterized by a convergent mapping from multi‐domain neurocognitive measures to a set of prefronto‐temporo‐limbic and subcortical structures. Furthermore, a neuroanatomical separation between positive and negative brain–cognition correlations may not only point to a biological process determining the clinical risk for disease transition, but also to possible compensatory or dysmaturational neural processes. Hum Brain Mapp, 2011. © 2011 Wiley‐Liss, Inc. (Source: Human Brain Mapping) Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5176533 Mon, 29 Aug 2011 23:00:00 +0100 5176533 http://www.medworm.com/index.php?rid=5176532&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21345 This study addresses how visual food cues are encoded in reward related brain areas and whether this encoding might provide information to differentiate between patients suffering from eating disorders [binge‐eating disorder (BED) and bulimia nervosa (BN)], overweight controls (C‐OW), and normal‐weight controls (C‐NW). Participants passively viewed pictures of food stimuli and neutral stimuli in a cue reactivity design. Two classification analyses were conducted. First, we used multivariate pattern recognition techniques to decode the category of a currently viewed picture from local brain activity patterns. In the second analysis, we applied an ensemble classifier to predict the clinical status of subjects (BED, BN, C‐OW, and C‐NW) based on food‐related brain response patter... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5176532 Mon, 29 Aug 2011 23:00:00 +0100 5176532 http://www.medworm.com/index.php?rid=5176531&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21347 AbstractAlthough the involvement of the anterior cingulate cortex (ACC) in emotional response inhibition is well established, there are several outstanding issues about the nature of this involvement that are not well understood. The present study aimed to examine the precise contribution of the ACC to emotion‐modulated response inhibition by capitalizing on fine temporal resolution of the event‐related potentials (ERPs) and the recent advances in source localization. To this end, participants (N = 30) performed an indirect affective Go/Nogo task (i.e., unrelated to the emotional content of stimulation) that required the inhibition of a motor response to three types of visual stimuli: arousing negative (A−), neutral (N), and arousing positive (A+). Behavioral data revealed that parti... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5176531 Mon, 29 Aug 2011 23:00:00 +0100 5176531 http://www.medworm.com/index.php?rid=5176530&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21349 In conclusion, TBM findings complement reports of frontal, temporal, and ventricular dysmorphology in schizophrenia and further indicate that putamen/pallidum enlargements, originally linked mainly with medication exposure in early studies, also reflect a genetic predisposition for schizophrenia. Thus, brain deformation profiles revealed in this study may help to clarify the role of specific genetic or environmental risk factors toward altered brain morphology in schizophrenia. Hum Brain Mapp, 2011. © 2011 Wiley‐Liss, Inc. (Source: Human Brain Mapping) Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5176530 Mon, 29 Aug 2011 23:00:00 +0100 5176530 http://www.medworm.com/index.php?rid=5176529&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21351 AbstractAberrant sensitivity of incentive neurocircuitry to nondrug rewards has been suggested as either a risk factor for or consequence of drug addiction. Using functional magnetic resonance imaging, we tested whether alcohol‐dependent patients (ADP: n = 29) showed altered recruitment of ventral striatal (VS) incentive neurocircuitry compared to controls (n = 23) by: (1) cues to respond for monetary rewards, (2) post‐response anticipation of rewards, or (3) delivery of rewards. Using an instrumental task with two‐stage presentation of reward‐predictive information, subjects saw cues signaling opportunities to win $0, $1, or $10 for responding to a target. Following this response, subjects were notified whether their success would be indicated by a lexical notification (“Hit?”... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5176529 Mon, 29 Aug 2011 23:00:00 +0100 5176529 http://www.medworm.com/index.php?rid=5176528&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21353 We report no associations (P > 0.05) between either global or central midlife obesity and subsequent rates of regional brain volume changes against a background of age‐related atrophy in older individuals who remained nondemented. When looking at the entire sample, greater decline was observed in the volume of gray matter, precuneus, cingulate and orbito‐frontal gyri for globally obese (P < 0.03), even though only data up to the point of dementia diagnosis were included in the analyses (i.e., while still considered clinically normal). Moreover, when trajectories of regional volume changes were examined across the range of BMI and waist circumference values instead of employing a cut‐off point to define obesity, a different pattern of results emerged. Overall, our results sugges... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5176528 Mon, 29 Aug 2011 23:00:00 +0100 5176528 http://www.medworm.com/index.php?rid=5176527&cid=s_33635_25_f&fid=33635&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fhbm.21387 AbstractAs it is the case in brainstorming, each single idea a person generates to a specific problem may stimulate new ideas or solutions in others. In this fMRI study, we investigate the effects of cognitive stimulation via the exposure to other people's ideas on the originality of generated ideas. Participants are requested to generate alternative uses of conventional everyday objects subsequent to a short cognitive stimulation intervention in which they are exposed to other ideas, which were either common or highly original. In a control condition, meaningless pseudowords are shown. Results suggest that cognitive stimulation via common or moderately creative ideas was effective in improving creativity. At the neurophysiological level, temporo‐parietal brain regions (primarily right�... Human Brain Mapping journals http://www.medworm.com/rss/comments.php?id=5176527 Mon, 29 Aug 2011 23:00:00 +0100 5176527