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 'Cerebral Cortex' source. Wed, 08 Feb 2012 20:43:01 +0100 http://www.medworm.com/index.php?rid=5584572&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F22%2F2%2F482%3Frss%3D1 We examined the Amazonian rodent agouti (Dasyprocta agouti) and the marmoset monkey (Callithrix jacchus) to further understand relationships among progenitor compartmentalization, proportions of various cortical progenitors, and degree of cortical folding. We identified a similar cytoarchitectonic distinction between the OSVZ and ISVZ at midgestation in both species. In the marmoset, we quantified the ventricular and abventricular divisions and observed similar proportions as previously described for the human and ferret brains. The proportions of radial glia, intermediate progenitors, and outer radial glial cell (oRG) populations were similar in midgestation lissencephalic marmoset as in gyrencephalic human or ferret. Our findings suggest that cytoarchitectonic subdivisions of SVZ are an ... Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5584572 Wed, 11 Jan 2012 05:00:00 +0100 5584572 http://www.medworm.com/index.php?rid=5584571&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F22%2F2%2F469%3Frss%3D1 Subventricular zone (SVZ) progenitors are a hallmark of the developing neocortex. Recent studies described a novel type of SVZ progenitor that retains a basal process at mitosis, sustains expression of radial glial markers, and is capable of self-renewal. These progenitors, referred to here as basal radial glia (bRG), occur at high relative abundance in the SVZ of gyrencephalic primates (human) and nonprimates (ferret) but not lissencephalic rodents (mouse). Here, we analyzed the occurrence of bRG cells in the embryonic neocortex of the common marmoset Callithrix jacchus, a near-lissencephalic primate. bRG cells, expressing Pax6, Sox2 (but not Tbr2), glutamate aspartate transporter, and glial fibrillary acidic protein and retaining a basal process at mitosis, occur at similar relative abun... Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5584571 Wed, 11 Jan 2012 05:00:00 +0100 5584571 http://www.medworm.com/index.php?rid=5584570&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F22%2F2%2F465%3Frss%3D1 Recent advances in cell labeling and imaging techniques have dramatically expanded our knowledge of the neural precursor cells responsible for corticogenesis. In particular, radial glial cells are now known to generate several classes of restricted progenitors and neurons. While radial glial cells in the ventricular zone have received the most attention, it has become increasingly clear that a distinct subclass of radial glial cells situated in the subventricular zone (SVZ) and intermediate zone also play an important role in corticogenesis. These delaminated radial glial cells, which lack an apical process attached to the ventricular surface but maintain a basal process, were discovered over 3 decades ago. Recently, they have been further characterized as cortical progenitors and renamed ... Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5584570 Wed, 11 Jan 2012 05:00:00 +0100 5584570 http://www.medworm.com/index.php?rid=5584569&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F22%2F2%2F455%3Frss%3D1 Cerebral axonal connections begin to develop before birth during radial migration in each brain area. A number of theories are still actively debated regarding the link between neuronal migration, developing connectivity, and gyrification. Here, we used high angular resolution diffusion tractography on postmortem fetal human brains (postconception week (W) 17–40) to document the regression of radial and tangential organization likely to represent migration pathways and the emergence of corticocortical organization and gyrification. The dominant radial organization at W17 gradually diminished first in dorsal parieto-occipital and later in ventral frontotemporal regions with regional variation: radial organization persisted longer in the crests of gyri than at the depths of sulci. The ... Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5584569 Wed, 11 Jan 2012 05:00:00 +0100 5584569 http://www.medworm.com/index.php?rid=5584568&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F22%2F2%2F446%3Frss%3D1 We have recently shown that interference with repetitive transcranial magnetic stimulation (rTMS) of right posterior intraparietal sulcus (IPS) cortex during the allocation of spatial attention leads to abnormal desynchronization of anticipatory (pretarget) electroencephalographic alpha rhythms (8–12 Hz) in occipital–parietal cortex and the detection of subsequently presented visual targets (Capotosto et al. 2009). Since lesion data suggest that lesions of the right frontoparietal cortices produce more severe and long-lasting deficits of visual spatial attention than lesions of the left hemisphere, here, we used the mentioned rTMS-electroencephalographic procedure to test if the control of anticipatory alpha rhythms by IPS is asymmetrically organized in the 2 hemispheres. Resul... Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5584568 Wed, 11 Jan 2012 05:00:00 +0100 5584568 http://www.medworm.com/index.php?rid=5584567&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F22%2F2%2F436%3Frss%3D1 Everyday language is replete with descriptions of emotional events that people have experienced and wish to share with others. Such descriptions presumably rely on pairings of affective words and visual information (such as events and pictures) that have been learnt throughout one's development. To study this kind of affective language learning in the brain, we used functional neuroimaging during associative learning of emotional words and pictures. Brain imaging revealed increased activation of both primary emotional areas such as the amygdala and of higher cognitive areas such as the inferior frontal gyrus (IFG) and medial frontal gyrus. The dynamic causal modeling with Bayesian model selection suggested that the IFG first receives the input and that the connections are bidirectional, su... Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5584567 Wed, 11 Jan 2012 05:00:00 +0100 5584567 http://www.medworm.com/index.php?rid=5584566&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F22%2F2%2F426%3Frss%3D1 Nonrapid eye movement (NREM) sleep is characterized by periodic changes in cortical excitability that are reflected in the electroencephalography (EEG) as high-amplitude slow oscillations, indicative of cortical Up/Down states. These slow oscillations are thought to be involved in NREM sleep-dependent memory consolidation. Although the locus coeruleus (LC) noradrenergic system is known to play a role in off-line memory consolidation (that may occur during NREM sleep), cortico–coerulear interactions during NREM sleep have not yet been studied in detail. Here, we investigated the timing of LC spikes as a function of sleep-associated slow oscillations. Cortical EEG was monitored, along with activity of LC neurons recorded extracellularly, in nonanesthetized naturally sleeping rats. LC s... Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5584566 Wed, 11 Jan 2012 05:00:00 +0100 5584566 http://www.medworm.com/index.php?rid=5584565&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F22%2F2%2F417%3Frss%3D1 Spasmodic dysphonia (SD) is a primary focal dystonia characterized by involuntary spasms in the laryngeal muscles during speech production. Although recent studies have found abnormal brain function and white matter organization in SD, the extent of gray matter alterations, their structure–function relationships, and correlations with symptoms remain unknown. We compared gray matter volume (GMV) and cortical thickness (CT) in 40 SD patients and 40 controls using voxel-based morphometry and cortical distance estimates. These measures were examined for relationships with blood oxygen level–dependent signal change during symptomatic syllable production in 15 of the same patients. SD patients had increased GMV, CT, and brain activation in key structures of the speech control system... Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5584565 Wed, 11 Jan 2012 05:00:00 +0100 5584565 http://www.medworm.com/index.php?rid=5584564&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F22%2F2%2F403%3Frss%3D1 The relative contribution of intrinsic and extrinsic cues in the regulation of cortical neurogenesis remains a crucial challenge in developmental neurobiology. We previously reported that a transient population of glutamatergic neurons, the cortical plate (CP) transient neurons, migrates from the ventral pallium (VP) over long distances and participate in neocortical development. Here, we show that the genetic ablation of this population leads to a reduction in the number of cortical neurons especially fated to superficial layers. These defects result from precocious neurogenesis followed by a depletion of the progenitor pools. Notably, these changes progress from caudolateral to rostrodorsal pallial territories between E12.5 and E14.5 along the expected trajectory of the ablated cells. Co... Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5584564 Wed, 11 Jan 2012 05:00:00 +0100 5584564 http://www.medworm.com/index.php?rid=5584563&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F22%2F2%2F391%3Frss%3D1 Ventral visual cortex contains specialized regions for particular object categories, but little is known about how these regions interact during object recognition. Here we examine how the face-selective fusiform gyrus (FG) and the scene-selective parahippocampal cortex (PHC) interact with each other and with the rest of the brain during different visual tasks. To assess these interactions, we developed a novel approach for identifying patterns of connectivity associated with specific task sets, independent of stimulus-evoked responses. We tested whether this "background connectivity" between the FG and PHC was modulated when subjects engaged in face and scene processing tasks. In contrast to what would be predicted from biased competition or intrinsic activity accounts, we found that the ... Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5584563 Wed, 11 Jan 2012 05:00:00 +0100 5584563 http://www.medworm.com/index.php?rid=5584562&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F22%2F2%2F381%3Frss%3D1 Retention of information over extended time periods places special demands on the brain. The neural correlates of memory performance after a short delay of 30 min and a long delay of 1 week are likely partly different, but we do not know how structural maturation of the brain contributes to the differential development of these functions. This question was investigated in a sample of 107 children and adolescents aged 8–19 years. Measures used were structural magnetic resonance imaging and the Rey Complex Figure Test copy, organizational strategy, and 30-min and 1-week recall. While the amount of details copied and later recalled after both 30 min and 1 week increased with age, the relative saving over 1 week (1-week/30-min ratio score) did not increase with age. Thirty minutes recall... Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5584562 Wed, 11 Jan 2012 05:00:00 +0100 5584562 http://www.medworm.com/index.php?rid=5584561&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F22%2F2%2F372%3Frss%3D1 Visual imagery allows us to vividly imagine scenes in the absence of visual stimulation. The likeness of visual imagery to visual perception suggests that they might share neural mechanisms in the brain. Here, we directly investigated whether perception and visual imagery share cortical representations. Specifically, we used a combination of functional magnetic resonance imaging (fMRI) and multivariate pattern classification to assess whether imagery and perception encode the "category" of objects and their "location" in a similar fashion. Our results indicate that the fMRI response patterns for different categories of imagined objects can be used to predict the fMRI response patters for seen objects. Similarly, we found a shared representation of location in low-level and high-level ventr... Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5584561 Wed, 11 Jan 2012 05:00:00 +0100 5584561 http://www.medworm.com/index.php?rid=5584560&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F22%2F2%2F363%3Frss%3D1 Stopping an initiated response is an essential function, investigated in many studies with go/no-go and stop-signal paradigms. These standard tests require rapid action cancellation. This appears to be achieved by a suppression mechanism that has "global" effects on corticomotor excitability (i.e., affecting task-irrelevant muscles). By contrast, stopping action in everyday life may require selectivity (i.e., targeting a specific response tendency without affecting concurrent action). We hypothesized that while standard stopping engages global suppression, behaviorally selective stopping engages a selective suppression mechanism. Accordingly, we measured corticomotor excitability of the task-irrelevant leg using transcranial magnetic stimulation while subjects stopped the hand. Experiment ... Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5584560 Wed, 11 Jan 2012 05:00:00 +0100 5584560 http://www.medworm.com/index.php?rid=5584559&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F22%2F2%2F345%3Frss%3D1 The pontine nuclei (PN) are the major intermediary elements in the corticopontocerebellar pathway. Here we asked if the PN may help to adapt the spatial reference frames used by cerebrocortical neurons involved in the sensory guidance of movement to a format potentially more appropriate for the cerebellum. To this end, we studied movement-related neurons in the dorsal PN (DPN) of monkeys, most probably projecting to the cerebellum, executing fixed vector saccades or, alternatively, fixed vector hand reaches from different starting positions. The 83 task-related neurons considered fired movement-related bursts before saccades (saccade-related) or before hand movements (hand movement-related). About 40% of the SR neurons were "oculocentric," whereas the others were modulated by eye starting ... Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5584559 Wed, 11 Jan 2012 05:00:00 +0100 5584559 http://www.medworm.com/index.php?rid=5584558&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F22%2F2%2F337%3Frss%3D1 We investigated the key anatomical structures mediating interhemispheric integration during the perception of apparent motion across the retinal midline. Previous studies of commissurotomized patients suggest that subcortical structures mediate interhemispheric transmission but the specific regions involved remain unclear. Here, we exploit interindividual variations in the propensity of normal subjects to perceive horizontal motion, in relation to vertical motion. We characterize these differences psychophysically using a Dynamic Dot Quartet (an ambiguous stimulus that induces illusory motion). We then tested for correlations between a tendency to perceive horizontal motion and fractional anisotropy (FA) (from structural diffusion tensor imaging), over subjects. FA is an indirect measure o... Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5584558 Wed, 11 Jan 2012 05:00:00 +0100 5584558 http://www.medworm.com/index.php?rid=5584557&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F22%2F2%2F327%3Frss%3D1 The mesocortical pathway projecting from the ventral tegmental area (VTA) to the prefrontal cortex (PFC) plays a critical role in a number of cognitive and emotional processes. While this pathway has been traditionally viewed as dopaminergic, recent data indicate that a considerable proportion of rostromedial VTA neurons possess markers for glutamate transmission. However, the relative density of the glutamatergic projection to the PFC from these rostromedial regions is unknown. In the present study, anterograde tracer injections into 4 ventral midbrain subregions were coupled with immunohistochemical analysis of labeled axons in PFC for markers of dopamine (DA; tyrosine hydroxylase [TH]) and glutamate (vesicular glutamate transporter 2; VGLUT2). We found that while tracer injections into ... Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5584557 Wed, 11 Jan 2012 05:00:00 +0100 5584557 http://www.medworm.com/index.php?rid=5584556&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F22%2F2%2F308%3Frss%3D1 The intrinsic functional architecture of early cortical areas in highly visual mammals is characterized by the presence of domains and pinwheels, with orientation preference of the inputs to these regions being more and less selective, respectively. We exploited this organizational feature to investigate mechanisms supporting extraclassical surround suppression, a process thought to be critical for figure ground segregation and form vision. Combining intrinsic signal optical imaging and single-unit recording in V1 of anesthetized cats, we show for the first time that the orientation tuning of the suppressive surround is sharper for domain than for pinwheel neurons. This difference depends on high center gain and is more pronounced in superficial cortex. In addition, when we remove the near... Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5584556 Wed, 11 Jan 2012 05:00:00 +0100 5584556 http://www.medworm.com/index.php?rid=5584555&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F22%2F2%2F294%3Frss%3D1 During visual fixation, the eyes make fast involuntary miniature movements known as microsaccades (MSs). When MSs are executed they displace the visual image over the retina and can generate neural modulation along the visual pathway. However, the effects of MSs on neural activity have substantial variability and are not fully understood. By utilizing voltage-sensitive dye imaging, we imaged the spatiotemporal patterns induced by MSs in V1 and V2 areas of behaving monkeys while they were fixating and presented with visual stimuli. We then investigated the neuronal modulation dynamics, induced by MSs, under different visual stimulation. MSs induced monophasic or biphasic neural responses depending on stimulus size. These neural responses were accompanied by different spatiotemporal patterns... Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5584555 Wed, 11 Jan 2012 05:00:00 +0100 5584555 http://www.medworm.com/index.php?rid=5584554&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F22%2F2%2F286%3Frss%3D1 Many empiricist theories hold that concepts are composed of sensory–motor primitives. For example, the meaning of the word "run" is in part a visual image of running. If action concepts are partly visual, then the concepts of congenitally blind individuals should be altered in that they lack these visual features. We compared semantic judgments and neural activity during action verb comprehension in congenitally blind and sighted individuals. Participants made similarity judgments about pairs of nouns and verbs that varied in the visual motion they conveyed. Blind adults showed the same pattern of similarity judgments as sighted adults. We identified the left middle temporal gyrus (lMTG) brain region that putatively stores visual–motion features relevant to action verbs. The fu... Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5584554 Wed, 11 Jan 2012 05:00:00 +0100 5584554 http://www.medworm.com/index.php?rid=5584553&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F22%2F2%2F274%3Frss%3D1 Negative emotional signals are known to influence task performance, but so far, investigations have focused on how emotion interacts with perceptual processes by mobilizing attentional resources. The attention-independent effects of negative emotional signals are less well understood. Here, we show that threat signals trigger defensive responses independently of what observers pay attention to. Participants were scanned using functional magnetic resonance imaging while watching short video clips of threatening actions and performed either color or emotion judgments. Seeing threatening actions interfered with performance in both tasks. Amygdala activation reflected both stimulus and task conditions. In contrast, threat stimuli prompted a constant activity in a network underlying reflexive d... Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5584553 Wed, 11 Jan 2012 05:00:00 +0100 5584553 http://www.medworm.com/index.php?rid=5584552&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F22%2F2%2F260%3Frss%3D1 Category knowledge can be explicit, yet not conform to a perfect rule. For example, a child may acquire the rule "If it has wings, then it is a bird," but then must account for exceptions to this rule, such as bats. The current study explored the neurobiological basis of rule-plus-exception learning by using quantitative predictions from a category learning model, SUSTAIN, to analyze behavioral and functional magnetic resonance imaging (fMRI) data. SUSTAIN predicts that exceptions require formation of specialized representations to distinguish exceptions from rule-following items in memory. By incorporating quantitative trial-by-trial predictions from SUSTAIN directly into fMRI analyses, we observed medial temporal lobe (MTL) activation consistent with 2 predicted psychological processes t... Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5584552 Wed, 11 Jan 2012 05:00:00 +0100 5584552 http://www.medworm.com/index.php?rid=5584551&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F22%2F2%2F251%3Frss%3D1 Behavioral variant frontotemporal dementia (bvFTD) erodes complex social–emotional functions as the anterior cingulate cortex (ACC) and frontoinsula (FI) degenerate, but the early vulnerable neuron within these regions has remained uncertain. Previously, we demonstrated selective loss of ACC von Economo neurons (VENs) in bvFTD. Unlike ACC, FI contains a second conspicuous layer 5 neuronal morphotype, the fork cell, which has not been previously examined. Here, we investigated the selectivity, disease-specificity, laterality, timing, and symptom relevance of frontoinsular VEN and fork cell loss in bvFTD. Blinded, unbiased, systematic sampling was used to quantify bilateral FI VENs, fork cells, and neighboring neurons in 7 neurologically unaffected controls (NC), 5 patients with Alzhei... Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5584551 Wed, 11 Jan 2012 05:00:00 +0100 5584551 http://www.medworm.com/index.php?rid=5584550&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F22%2F2%2F245%3Frss%3D1 Human anterior cingulate and frontoinsular cortices participate in healthy social-emotional processing. These regions feature 2 related layer 5 neuronal morphotypes, the von Economo neurons and fork cells. In this paper, we review the historical accounts of these neurons and provide a German-to-English translation of von Economo's seminal paper describing the neurons which have come to bear his name. We close with a brief discussion regarding the functional and clinical relevance of these neurons and their home regions. (Source: Cerebral Cortex) Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5584550 Wed, 11 Jan 2012 05:00:00 +0100 5584550 http://www.medworm.com/index.php?rid=5584549&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F22%2F2%2FNP-c%3Frss%3D1 (Source: Cerebral Cortex) Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5584549 Wed, 11 Jan 2012 05:00:00 +0100 5584549 http://www.medworm.com/index.php?rid=5584548&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F22%2F2%2FNP-b%3Frss%3D1 (Source: Cerebral Cortex) Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5584548 Wed, 11 Jan 2012 05:00:00 +0100 5584548 http://www.medworm.com/index.php?rid=5584547&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F22%2F2%2FNP-a%3Frss%3D1 (Source: Cerebral Cortex) Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5584547 Wed, 11 Jan 2012 05:00:00 +0100 5584547 http://www.medworm.com/index.php?rid=5584546&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F22%2F2%2FNP%3Frss%3D1 (Source: Cerebral Cortex) Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5584546 Wed, 11 Jan 2012 05:00:00 +0100 5584546 http://www.medworm.com/index.php?rid=5506687&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F22%2F1%2F244%3Frss%3D1 (Source: Cerebral Cortex) Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5506687 Tue, 13 Dec 2011 05:00:00 +0100 5506687 http://www.medworm.com/index.php?rid=5506685&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F22%2F1%2F232%3Frss%3D1 Contralateral recruitment remains a controversial phenomenon in both the clinical and normative populations. To investigate the neural correlates of this phenomenon, we explored the tendency for older adults to recruit prefrontal cortex (PFC) regions contralateral to those most active in younger adults. Participants were scanned with diffusion tensor imaging and functional magnetic rresonance imaging during a lateralized word matching task (unilateral vs. bilateral). Cross-hemispheric communication was measured behaviorally as greater accuracy for bilateral than unilateral trials (bilateral processing advantage [BPA]) and at the neural level by functional and structural connectivity between contralateral PFC. Compared with the young, older adults exhibited 1) greater BPAs in the behavioral... Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5506685 Tue, 13 Dec 2011 05:00:00 +0100 5506685 http://www.medworm.com/index.php?rid=5506684&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F22%2F1%2F221%3Frss%3D1 The McGurk effect demonstrates the influence of visual cues on auditory perception. Mismatching information from both sensory modalities can fuse to a novel percept that matches neither the auditory nor the visual stimulus. This illusion is reported in 60–80% of trials. We were interested in the impact of ongoing brain oscillations—indexed by fluctuating local excitability and interareal synchronization—on upcoming perception of identical stimuli. The perception of the McGurk effect is preceded by high beta activity in parietal, frontal, and temporal areas. Beta activity is pronounced in the left superior temporal gyrus (lSTG), which is considered as a site of multimodal integration. This area is functionally (de)coupled to distributed frontal and temporal regions in illu... Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5506684 Tue, 13 Dec 2011 05:00:00 +0100 5506684 http://www.medworm.com/index.php?rid=5506683&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F22%2F1%2F209%3Frss%3D1 This study combined neurophysiological measures, including functional magnetic resonance imaging, eye-tracking, and pupillary response with behavioral measures assessing affective and moral judgments across age. One hundred and twenty-six participants aged between 4 and 37 years viewed scenarios depicting intentional versus accidental actions that caused harm/damage to people and objects. Morally, salient scenarios evoked stronger empathic sadness in young participants and were associated with enhanced activity in the amygdala, insula, and temporal poles. While intentional harm was evaluated as equally wrong across all participants, ratings of deserved punishments and malevolent intent gradually became more differentiated with age. Furthermore, age-related increase in activity was detected... Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5506683 Tue, 13 Dec 2011 05:00:00 +0100 5506683 http://www.medworm.com/index.php?rid=5506682&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F22%2F1%2F201%3Frss%3D1 We presented naturalistic combinations of virtual self-movement stimuli while recording neuronal activity in monkey cerebral cortex. Monkeys used a joystick to drive to a straight ahead heading direction guided by either object motion or optic flow. The selected cue dominates neuronal responses, often mimicking responses evoked when that stimulus is presented alone. In some neurons, driving strategy creates selective response additivities. In others, it creates vulnerabilities to the disruptive effects of independently moving objects. Such cue interactions may be related to the disruptive effects of independently moving objects in Alzheimer's disease patients with navigational deficits. (Source: Cerebral Cortex) Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5506682 Tue, 13 Dec 2011 05:00:00 +0100 5506682 http://www.medworm.com/index.php?rid=5506681&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F22%2F1%2F191%3Frss%3D1 We determined the location, functional response profile, and structural fiber connections of auditory areas with voice- and emotion-sensitive activity using functional magnetic resonance imaging (fMRI) and diffusion tensor imaging. Bilateral regions responding to emotional voices were consistently found in the superior temporal gyrus, posterolateral to the primary auditory cortex. Event-related fMRI showed stronger responses in these areas to voices-expressing anger, sadness, joy, and relief, relative to voices with neutral prosody. Their neural responses were primarily driven by prosodic arousal, irrespective of valence. Probabilistic fiber tracking revealed direct structural connections of these "emotional voice areas" (EVA) with ipsilateral medial geniculate body, which is the major inp... Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5506681 Tue, 13 Dec 2011 05:00:00 +0100 5506681 http://www.medworm.com/index.php?rid=5506680&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F22%2F1%2F175%3Frss%3D1 The insula of Reil represents a large cortical territory buried in the depth of the lateral sulcus and subdivided into 3 major cytoarchitectonic domains: agranular, dysgranular, and granular. The present study aimed at reinvestigating the architectonic organization of the monkey's insula using multiple immunohistochemical stainings (parvalbumin, PV; nonphosphorylated neurofilament protein, with SMI-32; acetylcholinesterase, AChE) in addition to Nissl and myelin. According to changes in density and laminar distributions of the neurochemical markers, several zones were defined and related to 8 cytoarchitectonic subdivisions (Ia1–Ia2/Id1–Id3/Ig1–Ig2/G). Comparison of the different patterns of staining on unfolded maps of the insula revealed: 1) parallel ventral to dorsal gra... Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5506680 Tue, 13 Dec 2011 05:00:00 +0100 5506680 http://www.medworm.com/index.php?rid=5506679&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F22%2F1%2F166%3Frss%3D1 The capacity to imagine being somewhere else and seeing the environment from a different point of view is crucial for spatial planning in daily life and for understanding the intentions, actions, and state of mind of other people. The neural bases of spatial updating of multiple object locations were investigated using functional magnetic resonance imaging. Healthy volunteers saw an array of objects on a table in a virtual reality environment and imagined movement of their own viewpoint or rotation of the array. Their memory for the locations of the objects was then tested with a change-detection task. Behavioral results confirmed the advantage for imagined viewpoint change compared with imagined array rotation of equivalent size. Encoding of object locations was associated with a network ... Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5506679 Tue, 13 Dec 2011 05:00:00 +0100 5506679 http://www.medworm.com/index.php?rid=5506678&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F22%2F1%2F158%3Frss%3D1 Decoding specific cognitive states from brain activity constitutes a major goal of neuroscience. Previous studies of brain-state classification have focused largely on decoding brief, discrete events and have required the timing of these events to be known. To date, methods for decoding more continuous and purely subject-driven cognitive states have not been available. Here, we demonstrate that free-streaming subject-driven cognitive states can be decoded using a novel whole-brain functional connectivity analysis. Ninety functional regions of interest (ROIs) were defined across 14 large-scale resting-state brain networks to generate a 3960 cell matrix reflecting whole-brain connectivity. We trained a classifier to identify specific patterns of whole-brain connectivity as subjects rested qu... Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5506678 Tue, 13 Dec 2011 05:00:00 +0100 5506678 http://www.medworm.com/index.php?rid=5506677&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F22%2F1%2F144%3Frss%3D1 The cingulate and retrosplenial regions are major components of the dorsomedial (dm) limbic cortex and have been implicated in a range of cognitive functions such as emotion, attention, and spatial memory. While the structure and connectivity of these cortices are well characterized, little is known about their development. Notably, the timing and mode of migration that govern the appropriate positioning of late-born neurons remain unknown. Here, we analyzed migratory events during the early postnatal period from ventricular/subventricular zone (VZ/SVZ) to the cerebral cortex by transducing neuronal precursors in the VZ/SVZ of newborn rats/mice with Tomato/green fluorescent protein–encoding lentivectors. We have identified a pool of postmitotic pyramidal precursors in the dm part of ... Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5506677 Tue, 13 Dec 2011 05:00:00 +0100 5506677 http://www.medworm.com/index.php?rid=5506676&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F22%2F1%2F132%3Frss%3D1 There is an increasing interest to integrate electrophysiological and hemodynamic measures for characterizing spatial and temporal aspects of cortical processing. However, an informative combination of responses that have markedly different sensitivities to the underlying neural activity is not straightforward, especially in complex cognitive tasks. Here, we used parametric stimulus manipulation in magnetoencephalography (MEG) and functional magnetic resonance imaging (fMRI) recordings on the same subjects, to study effects of noise on processing of spoken words and environmental sounds. The added noise influenced MEG response strengths in the bilateral supratemporal auditory cortex, at different times for the different stimulus types. Specifically for spoken words, the effect of noise on ... Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5506676 Tue, 13 Dec 2011 05:00:00 +0100 5506676 http://www.medworm.com/index.php?rid=5506675&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F22%2F1%2F122%3Frss%3D1 Motor planning is a hierarchical process that is typically organized around an action's goal (e.g., drinking from a cup). However, the motor plan depends not only on the goal but also on the current body state. Here, we investigated how one's own body posture interacts with planning of goal-directed actions. Participants engaged in a grasp selection (GS) task while we manipulated their arm posture. They had to indicate how they would grasp a bar when transporting it from a start to goal position and orientation. We compared situations in which one's body posture was in-congruent with the start posture and/or goal posture of the planned movement. Behavioral results show that GS took longer when one's own body state was incongruent with the goal posture of the planned movement. Corresponding... Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5506675 Tue, 13 Dec 2011 05:00:00 +0100 5506675 http://www.medworm.com/index.php?rid=5506674&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F22%2F1%2F112%3Frss%3D1 Persistent motor/cognitive alterations and increased prevalence of Alzheimer's disease are known consequences of recurrent sports concussions, the most prevalent cause of mild traumatic brain injury (TBI) among youth. Animal models of TBI demonstrated that impaired learning was related to persistent synaptic plasticity suppression in the form of long-term potentiation (LTP) and depression (LTD). In humans, single and repeated concussive injuries lead to lifelong and cumulative enhancements of gamma-aminobutyric acid (GABA)–mediated inhibition, which is known to suppress LTP/LTD plasticity. To test the hypothesis that increased GABAergic inhibition after repeated concussions suppresses LTP/LTD and contributes to learning impairments, we used a paired associative stimulation (PAS) prot... Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5506674 Tue, 13 Dec 2011 05:00:00 +0100 5506674 http://www.medworm.com/index.php?rid=5506673&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F22%2F1%2F99%3Frss%3D1 The medial superior frontal cortex (SFC), including the supplementary motor area (SMA) and presupplementary motor area (preSMA), is implicated in movement and cognitive control, among other functions central to decision making. Previous studies delineated the anatomical boundaries and functional connectivity of the SMA. However, it is unclear whether the preSMA, which responds to a variety of behavioral tasks, comprises functionally distinct areas. With 24 seed regions systematically demarcated throughout the anterior and posterior medial SFC, we examined here the functional divisions of the medial SFC on the basis of the "correlograms" of resting-state functional magnetic resonance imaging data of 225 adult individuals. In addition to replicating segregation of the SMA and posterior preSM... Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5506673 Tue, 13 Dec 2011 05:00:00 +0100 5506673 http://www.medworm.com/index.php?rid=5506672&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F22%2F1%2F86%3Frss%3D1 The migration of cortical -aminobutyric acidergic interneurons has been extensively studied in rodent embryos, whereas few studies have documented their postnatal migration. Combining in vivo analysis together with time-lapse imaging on cortical slices, we explored the origin and migration of cortical interneurons during the first weeks of postnatal life. Strikingly, we observed that a large pool of GAD65-GFP–positive cells accumulate in the dorsal white matter region during the first postnatal week. Part of these cells divides and expresses the transcription factor paired box 6 indicating the presence of local transient amplifying precursors. The vast majority of these cells are immature interneurons expressing the neuronal marker doublecortin and partly the calcium-binding protein ... Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5506672 Tue, 13 Dec 2011 05:00:00 +0100 5506672 http://www.medworm.com/index.php?rid=5506671&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F22%2F1%2F74%3Frss%3D1 We examined functional magnetic resonance imaging data for closely matched perceptual and recognition memory tasks for faces that engaged right PrC equivalently. Multivariate seed analyses revealed distinct patterns of interactions: Right ventrolateral prefrontal and posterior cingulate cortices exhibited stronger functional connectivity with PrC in recognition memory; fusiform regions were part of the pattern that displayed stronger functional connectivity with PrC in perceptual discrimination. Structural equation modeling revealed distinct patterns of effective connectivity that allowed us to constrain interpretation of these findings. Overall, they demonstrate that, even when MTL structures show similar involvement in recognition memory and perceptual discrimination, differential neural... Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5506671 Tue, 13 Dec 2011 05:00:00 +0100 5506671 http://www.medworm.com/index.php?rid=5506670&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F22%2F1%2F60%3Frss%3D1 Visual area V5/MT in the rhesus macaque has a distinct functional organization, where neurons with specific preferences for direction of motion and binocular disparity are co-organized in columns or clusters. Here, we analyze the pattern of intrinsic connectivity within cortical area V5/MT in both parasagittal sections of the intact brain and tangential sections from flatmounted cortex using small injections of the retrograde tracer cholera toxin subunit b. Labeled cells were predominantly found in cortical layers 2, 3, and 6. Going along the cortical layers, labeled cells were concentrated in regularly spaced clusters. The clusters nearest to the injection site were approximately 2 mm from its center. In flatmounted cortex, along the dorsoventral axis of V5/MT, we identified further clust... Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5506670 Tue, 13 Dec 2011 05:00:00 +0100 5506670 http://www.medworm.com/index.php?rid=5506669&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F22%2F1%2F51%3Frss%3D1 Motor control relies on well-established motor circuits, which are critical for typical child development. Although many imaging studies have examined task activation during motor performance, none have examined the relationship between functional intrinsic connectivity and motor ability. The current study investigated the relationship between resting state functional connectivity within the motor network and motor performance assessment outside of the scanner in 40 typically developing right-handed children. Better motor performance correlated with greater left-lateralized (mean left hemisphere—mean right hemisphere) motor circuit connectivity. Speed, rhythmicity, and control of movements were associated with connectivity within different individual region pairs: faster speed was as... Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5506669 Tue, 13 Dec 2011 05:00:00 +0100 5506669 http://www.medworm.com/index.php?rid=5506668&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F22%2F1%2F37%3Frss%3D1 Age-related declines in source memory have been observed for various stimuli and associated details. These impairments may be related to alterations in brain regions contributing to source memory via material-independent processes and/or regions specialized for processing specific materials. Using event-related functional magnetic resonance imaging, we investigate the effects of aging on source memory and associated neural activity for words and objects. Source accuracy was equally impaired in older adults for both materials. Imaging data revealed both groups recruited similar networks of regions to support source memory accuracy irrespective of material, including parietal and prefrontal cortices (PFC) and the hippocampus. Age-related decreases in material-independent activity linked to p... Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5506668 Tue, 13 Dec 2011 05:00:00 +0100 5506668 http://www.medworm.com/index.php?rid=5506667&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F22%2F1%2F26%3Frss%3D1 In conclusion, SE stimulates neurogenesis in a position-dependent manner and coincidence of neurogenesis and stronger EA distal to the injection site suggests a proepileptogenic effect of increased neurogenesis. (Source: Cerebral Cortex) Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5506667 Tue, 13 Dec 2011 05:00:00 +0100 5506667 http://www.medworm.com/index.php?rid=5506666&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F22%2F1%2F13%3Frss%3D1 In this study, we present a dedicated image analysis framework and its application for the detection of folding patterns during the critical period for the formation of many primary sulci (20–28 gestational weeks). Using structural information from in utero MRI, we perform morphometric analysis of cortical plate surface development and modeling of early folding in the normal fetal brain. First, we identify regions of the fetal brain surface that undergo significant folding changes during this developmental period and provide precise temporal staging of these changes for each region of interest. Then, we highlight the emergence of interhemispheric structural asymmetries that may be related to future functional specialization of cortical areas. Our findings complement previous descript... Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5506666 Tue, 13 Dec 2011 05:00:00 +0100 5506666 http://www.medworm.com/index.php?rid=5506665&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F22%2F1%2F1%3Frss%3D1 Using a population-based sampling strategy, the National Institutes of Health (NIH) Magnetic Resonance Imaging Study of Normal Brain Development compiled a longitudinal normative reference database of neuroimaging and correlated clinical/behavioral data from a demographically representative sample of healthy children and adolescents aged newborn through early adulthood. The present paper reports brain volume data for 325 children, ages 4.5–18 years, from the first cross-sectional time point. Measures included volumes of whole-brain gray matter (GM) and white matter (WM), left and right lateral ventricles, frontal, temporal, parietal and occipital lobe GM and WM, subcortical GM (thalamus, caudate, putamen, and globus pallidus), cerebellum, and brainstem. Associations with cross-sectio... Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5506665 Tue, 13 Dec 2011 05:00:00 +0100 5506665 http://www.medworm.com/index.php?rid=5506664&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F22%2F1%2FNP-c%3Frss%3D1 (Source: Cerebral Cortex) Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5506664 Tue, 13 Dec 2011 05:00:00 +0100 5506664 http://www.medworm.com/index.php?rid=5506663&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F22%2F1%2FNP-b%3Frss%3D1 (Source: Cerebral Cortex) Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5506663 Tue, 13 Dec 2011 05:00:00 +0100 5506663 http://www.medworm.com/index.php?rid=5506662&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F22%2F1%2FNP-a%3Frss%3D1 (Source: Cerebral Cortex) Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5506662 Tue, 13 Dec 2011 05:00:00 +0100 5506662 http://www.medworm.com/index.php?rid=5506661&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F22%2F1%2FNP%3Frss%3D1 (Source: Cerebral Cortex) Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5506661 Tue, 13 Dec 2011 05:00:00 +0100 5506661 http://www.medworm.com/index.php?rid=5389766&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F21%2F12%2F2893%3Frss%3D1 The identification of a face comprises processing of both visual features and conceptual knowledge. Studies showing that the fusiform face area (FFA) is sensitive to face identity generally neglect this dissociation. The present study is the first that isolates conceptual face processing by using words presented in a person context instead of faces. The design consisted of 2 different conditions. In one condition, participants were presented with blocks of words related to each other at the categorical level (e.g., brands of cars, European cities). The second condition consisted of blocks of words linked to the personality features of a specific face. Both conditions were created from the same 8 x 8 word matrix, thereby controlling for visual input across conditions. Univariate statistical... Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5389766 Fri, 04 Nov 2011 04:00:00 +0100 5389766 http://www.medworm.com/index.php?rid=5389765&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F21%2F12%2F2883%3Frss%3D1 In cats with central retinal lesions, deprivation of the lesion projection zone (LPZ) in primary visual cortex (area 17) induces remapping of the cortical topography. Recovery of visually driven cortical activity in the LPZ involves distinct changes in protein expression. Recent observations, about molecular activity changes throughout area 17, challenge the view that its remote nondeprived parts would not be involved in this recovery process. We here investigated the dynamics of the protein expression pattern of remote nondeprived area 17 triggered by central retinal lesions to explore to what extent far peripheral area 17 would contribute to the topographic map reorganization inside the visual cortex. Using functional proteomics, we identified 40 proteins specifically differentially expr... Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5389765 Fri, 04 Nov 2011 04:00:00 +0100 5389765 http://www.medworm.com/index.php?rid=5389764&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F21%2F12%2F2876%3Frss%3D1 The adult visual cortex maintains a substantial potential for plasticity in response to a change in visual input. For instance, transcranial magnetic stimulation (TMS) studies have shown that binocular deprivation (BD) increases the cortical excitability for inducing phosphenes with TMS. Here, we employed TMS to trace plastic changes in adult visual cortex before, during, and after 48 h of monocular deprivation (MD) of the right dominant eye. In healthy adult volunteers, MD-induced changes in visual cortex excitability were probed with paired-pulse TMS applied to the left and right occipital cortex. Stimulus–response curves were constructed by recording the intensity of the reported phosphenes evoked in the contralateral visual field at range of TMS intensities. Phosphene measurement... Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5389764 Fri, 04 Nov 2011 04:00:00 +0100 5389764 http://www.medworm.com/index.php?rid=5389763&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F21%2F12%2F2863%3Frss%3D1 Postischemic seizures are associated with worsened outcome following stroke, but the underlying pathophysiology is poorly understood. Here we examined acute seizures in adult mice following hypoxia–ischemia (HI) via combined behavioral, electrophysiological, and histological assessments. C57BL/6 mice aged 4–9 months received a permanent occlusion of the right common carotid artery and then underwent a systemic hypoxic episode. Generalized motor seizures were observed within 72 h following HI. These seizures occurred nearly exclusively in animals with extensive brain injury in the hemisphere ipsilateral to the carotid occlusion, but their generation was not associated with electroencephalographic discharges in bilateral hippocampal and neocortical recordings. Animals exhibiting ... Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5389763 Fri, 04 Nov 2011 04:00:00 +0100 5389763 http://www.medworm.com/index.php?rid=5389762&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F21%2F12%2F2850%3Frss%3D1 Valid expectations are known to improve target detection, but the preparatory attentional mechanisms underlying this perceptual facilitation remain an open issue. Using functional magnetic resonance imaging, we show here that expecting auditory, tactile, or visual targets, in the absence of stimulation, selectively increased baseline activity in corresponding sensory cortices and decreased activity in irrelevant ones. Regardless of sensory modality, expectancy activated bilateral premotor and posterior parietal areas, supplementary motor area as well as right anterior insula and right middle frontal gyrus. The bilateral putamen was sensitive to the modality specificity of expectations during the unexpected omission of targets. Thus, across modalities, detection improvement arising from sel... Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5389762 Fri, 04 Nov 2011 04:00:00 +0100 5389762 http://www.medworm.com/index.php?rid=5389761&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F21%2F12%2F2838%3Frss%3D1 Despite intersubject variability, dramatic impairments of socio-communicative skills are core features of autistic spectrum disorder (ASD). A deficit in the ability to express and understand emotions has often been hypothesized to be an important correlate of such impairments. Little is known about individuals with ASD’s ability to sense emotions conveyed by nonsocial stimuli such as music. Music has been found to be capable of evoking and conveying strong and consistent positive and negative emotions in healthy subjects. The ability to process perceptual and emotional aspects of music seems to be maintained in ASD. Individuals with ASD and neurotypical (NT) controls underwent a single functional magnetic resonance imaging (fMRI) session while processing happy and sad music excerpts.... Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5389761 Fri, 04 Nov 2011 04:00:00 +0100 5389761 http://www.medworm.com/index.php?rid=5389760&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F21%2F12%2F2829%3Frss%3D1 A central topic of controversy in the search for cortical mechanisms underlying perceptual awareness concerns the fundamental specialization of the visual system into a dorsal "vision-for-action/Where" stream and a ventral "vision-for-perception/What" stream. Specifically, it has been debated whether suppression of visual perception leads to differential reduction in brain activity in the 2 streams—with the dorsal stream remaining largely unaffected and the ventral stream showing a significant reduction in activity. Here, we examined this issue using the recently introduced method of continuous flash suppression (CFS), which offers a particularly sensitive measure of the link between perception and brain activity. Subjects had to detect, during CFS, images of manipulable man-made obj... Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5389760 Fri, 04 Nov 2011 04:00:00 +0100 5389760 http://www.medworm.com/index.php?rid=5389759&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F21%2F12%2F2820%3Frss%3D1 Temporal voice areas showing a larger activity for vocal than non-vocal sounds have been identified along the superior temporal sulcus (STS); more voice-sensitive areas have been described in frontal and parietal lobes. Yet, the role of voice-sensitive regions in representing voice identity remains unclear. Using a functional magnetic resonance adaptation design, we aimed at disentangling acoustic- from identity-based representations of voices. Sixteen participants were scanned while listening to pairs of voices drawn from morphed continua between 2 initially unfamiliar voices, before and after a voice learning phase. In a given pair, the first and second stimuli could be identical or acoustically different and, at the second session, perceptually similar or different. At both sessions, ri... Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5389759 Fri, 04 Nov 2011 04:00:00 +0100 5389759 http://www.medworm.com/index.php?rid=5389758&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F21%2F12%2F2809%3Frss%3D1 Estimates of working memory (WM) capacity increase in children, peak in young adulthood, and decline thereafter. Despite this symmetry, the mechanisms causing capacity increments in childhood may differ from those causing decline in old age. The contralateral delay activity (CDA) of the electroencephalogram, an event-related difference wave with a posterior scalp distribution, has been suggested as a neural marker of WM capacity. Here, we examine 22 children (10–12 years), 12 younger adults (20–25 years), and 22 older adults (70–75 years) in a cued change detection paradigm. Load levels and presentation times were varied within subjects. Behaviorally, we observed the expected life-span peak in younger adults and better performance with longer presentation times. With shor... Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5389758 Fri, 04 Nov 2011 04:00:00 +0100 5389758 http://www.medworm.com/index.php?rid=5389757&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F21%2F12%2F2797%3Frss%3D1 Parallel visual pathways in the primate brain known as the dorsal and ventral streams receive retinal inputs mainly through the magnocellular (M) and parvocellular (P) layers of the lateral geniculate nucleus. Inputs from these layers terminate within distinct parts of layer 4C of V1 (visual area 1). Due to the complexity of M- and P-derived neural connectivity in V1 and higher visual areas, the contributions of M and P inputs to the dorsal and ventral streams remain unclear. Employing retrograde transsynaptic transport of rabies virus, we analyzed the architecture of bottom–up pathways toward ventral stream area V4 (visual area 4) and dorsal stream area MT (middle temporal area). We found that V4 receives both M and P inputs "trisynaptically" from layer 4C via layer 2/3 of V1, where... Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5389757 Fri, 04 Nov 2011 04:00:00 +0100 5389757 http://www.medworm.com/index.php?rid=5389756&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F21%2F12%2F2788%3Frss%3D1 People are able to rapidly infer complex personality traits and mental states even from the most minimal person information. Research has shown that when observers view a natural scene containing people, they spend a disproportionate amount of their time looking at the social features (e.g., faces, bodies). Does this preference for social features merely reflect the biological salience of these features or are observers spontaneously attempting to make sense of complex social dynamics? Using functional neuroimaging, we investigated neural responses to social and nonsocial visual scenes in a large sample of participants (n = 48) who varied on an individual difference measure assessing empathy and mentalizing (i.e., empathizing). Compared with other scene categories, viewing natural social s... Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5389756 Fri, 04 Nov 2011 04:00:00 +0100 5389756 http://www.medworm.com/index.php?rid=5389755&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F21%2F12%2F2774%3Frss%3D1 Ischemic small vessel disease (SVD) may lead to cognitive impairment, but cognitive deficits with a given burden of SVD vary significantly. The underlying mechanisms of impaired or preserved cognition are unknown. Here, we investigated the impact of ischemic SVD on rapid-onset cortical plasticity, as induced with a paired-associative stimulation protocol. To exclude concomitant effects of aging, we examined 12 middle-aged patients (48.3 ± 8.3 years) with cerebral autosomal dominant arteriopathy with subcortical infarctions and leucoencephalopathy (CADASIL) who suffered from severe ischemic SVD and a group of 12 age-matched controls (49.9 ± 8.3 years). Cognitive status, motor performance and learning, and motor cortex excitability in response to cathodal transcranial direct cu... Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5389755 Fri, 04 Nov 2011 04:00:00 +0100 5389755 http://www.medworm.com/index.php?rid=5389754&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F21%2F12%2F2762%3Frss%3D1 Cortical activation and goal-directed behaviors characterize wakefulness. One cortical region especially involved in these phenomena is the medial prefrontal cortex (mPFC), which receives many inputs from cholinergic-containing neurons in brain stem structures implicated in arousal and wakefulness, such as the laterodorsal tegmental nucleus (LDT). Hypocretins/orexins (Hcrt/Ox), whose dysfunction is linked to narcolepsy, maintains arousal and stabilizes sleep–wakefulness states. We aim to determine if Hcrt1/OxA axons (1) innervate LDT neurons projecting to the mPFC, a target that would allow them to sustain arousal and wakefulness, and (2) target preferentially cholinergic versus noncholinergic LDT neurons. The retrograde tracer Fluorogold (FG) was injected in the rat mPFC, and dual i... Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5389754 Fri, 04 Nov 2011 04:00:00 +0100 5389754 http://www.medworm.com/index.php?rid=5389753&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F21%2F12%2F2751%3Frss%3D1 Recent evidence suggests the possibility that not all action modes depend on dorsal visual stream processing but that off-line nontarget-directed actions, such as antipointing, require additional and even distinct neural networks when compared with target-directed online actions. Here, we explored this potential dissociation in a group of 11 patients with left visual neglect, a syndrome characterized by a loss of awareness of the contralesional side of space. Ten healthy participants and 10 right hemisphere–damaged patients without neglect served as controls. Participants had to point either directly toward targets presented on their left or right (i.e., propointing) or to the mirror position in the opposite hemispace (i.e., antipointing). Compared with both control groups, neglect p... Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5389753 Fri, 04 Nov 2011 04:00:00 +0100 5389753 http://www.medworm.com/index.php?rid=5389752&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F21%2F12%2F2742%3Frss%3D1 The present study combined behavioral measures and diffusion tensor imaging to investigate the neuroanatomical basis of language learning in relation to phonological working memory (WM). Participants were exposed to simplified artificial languages under WM constraints. The results underscore the role of the rehearsal subcomponent of WM in successful speech segmentation and rule learning. Moreover, when rehearsal was blocked task performance was correlated to the white matter microstructure of the left ventral pathway connecting frontal and temporal language–related cortical areas through the extreme/external capsule. This ventral pathway may therefore play an important additional role in language learning when the main dorsal pathway–dependent rehearsal mechanisms are not avail... Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5389752 Fri, 04 Nov 2011 04:00:00 +0100 5389752 http://www.medworm.com/index.php?rid=5389751&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F21%2F12%2F2733%3Frss%3D1 The striatum has been identified as a new target for therapeutic deep brain stimulation in the treatment of neurological and psychiatric disorders. The nonhuman primate model offers opportunities for detailed mapping of the behavioral effects of stimulation within the striatum. We recently showed that dysfunction in the dorsal and ventral striatum was able to produce a specific pattern of abnormal movements and behavioral states. In the present study, electrical stimulation of monkey striatum evoked abnormal movements and behavioral states depending not only on the location of stimulation sites but also on the parameters of stimulation. Abnormal movements were induced by stimulation of sites in the anterior associative and posterior sensorimotor striatum. Short-train stimulation evoked myo... Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5389751 Fri, 04 Nov 2011 04:00:00 +0100 5389751 http://www.medworm.com/index.php?rid=5389750&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F21%2F12%2F2722%3Frss%3D1 The prefrontal cortex is considered essential for learning to perform cognitive tasks though little is known about how the representation of stimulus properties is altered by learning. To address this issue, we recorded neuronal activity in monkeys before and after training on a task that required visual working memory. After the subjects learned to perform the task, we observed activation of more prefrontal neurons and increased activity during working memory maintenance. The working memory–related increase in firing rate was due mostly to regular-spiking putative pyramidal neurons. Unexpectedly, the selectivity of neurons for stimulus properties and the ability of neurons to discriminate between stimuli decreased as the information about stimulus properties was apparently present i... Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5389750 Fri, 04 Nov 2011 04:00:00 +0100 5389750 http://www.medworm.com/index.php?rid=5389749&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F21%2F12%2F2712%3Frss%3D1 There is substantial interpatient variation in recovery from upper limb impairment after stroke in patients with severe initial impairment. Defining recovery as a change in the upper limb Fugl-Meyer score (FM), we predicted FM with its conditional expectation (i.e., posterior mean) given upper limb Fugl-Meyer initial impairment (FMii) and a putative functional magnetic resonance imaging (fMRI) recovery measure. Patients with first time, ischemic stroke were imaged at 2.5 ± 2.2 days poststroke with 1.5-T fMRI during a hand closure task alternating with rest (fundamental frequency = 0.025 Hz, scan duration = 172 s). Confirming a previous finding, we observed that the prediction of FM by FMii alone is good in patients with nonsevere initial hemiparesis but is not good in patients with ... Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5389749 Fri, 04 Nov 2011 04:00:00 +0100 5389749 http://www.medworm.com/index.php?rid=5389748&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F21%2F12%2F2704%3Frss%3D1 Accurate 3D determination of postsynaptic structures is essential to our understanding memory-related function and pathology in neurons. However, current methods of spine analysis require time-consuming and labor-intensive manual spine identification in large image data sets. Therefore, a realistic implementation of algorithm is necessary to replace manual identification. Here, we describe a new method for the automated detection of spines and dendrites based on analysis of geometrical features. Our "Spiso-3D" software carries out automated dendrite reconstruction and spine detection using both eigenvalue images and information of brightness, avoiding detection of pseudo-spines. To demonstrate the potential application of Spiso-3D automated analysis, we distinguished the rapid effects of a... Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5389748 Fri, 04 Nov 2011 04:00:00 +0100 5389748 http://www.medworm.com/index.php?rid=5389747&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F21%2F12%2F2696%3Frss%3D1 The present study aimed to investigate the role of frontopolar cortex in prospective memory (PM) by means of inhibitory theta-burst stimulation (cTBS). "Experiment 1"—8 volunteers were evaluated after inhibitory cTBS over left Brodmann area (BA) 10, right BA10, and Cz. In the PM procedure, sequences of 4 words each were presented. During the intersequence delay, subjects had to repeat the sequence in the observed order (ongoing task forward) or in the reverse order (backward). At the occurrence of a target word, subjects had to press a key on the keyboard (PM task). Recall and recognition of the target words were also tested. PM accuracy was lower after cTBS over left BA10 compared with Cz (P = 0.012), whereas it was comparable in right BA10 and Cz conditions. No other significant di... Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5389747 Fri, 04 Nov 2011 04:00:00 +0100 5389747 http://www.medworm.com/index.php?rid=5389746&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F21%2F12%2F2681%3Frss%3D1 While oscillations of the local field potential (LFP) are commonly attributed to the synchronization of neuronal firing rate on the same time scale, their relationship to coincident spiking in the millisecond range is unknown. Here, we present experimental evidence to reconcile the notions of synchrony at the level of spiking and at the mesoscopic scale. We demonstrate that only in time intervals of significant spike synchrony that cannot be explained on the basis of firing rates, coincident spikes are better phase locked to the LFP than predicted by the locking of the individual spikes. This effect is enhanced in periods of large LFP amplitudes. A quantitative model explains the LFP dynamics by the orchestrated spiking activity in neuronal groups that contribute the observed surplus synch... Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5389746 Fri, 04 Nov 2011 04:00:00 +0100 5389746 http://www.medworm.com/index.php?rid=5389745&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F21%2F12%2F2665%3Frss%3D1 The medial prefrontal cortex (mPFC) comprises an important component in the neural circuitry underlying drug-related associative learning and memory processing. Neuronal activation within mPFC circuits is correlated with the recall of opiate-related drug-taking experiences in both humans and other animals. Using an unbiased associative place conditioning procedure, we recorded mPFC neuronal populations during the acquisition, recall, and extinction phases of morphine-related associative learning and memory. Our analyses revealed that mPFC neurons show increased activity both in terms of tonic and phasic activity patterns during the acquisition phase of opiate reward-related memory and demonstrate stimulus-locked associative activity changes in real time, during the recall of opiate reward ... Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5389745 Fri, 04 Nov 2011 04:00:00 +0100 5389745 http://www.medworm.com/index.php?rid=5389744&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F21%2F12%2FNP-c%3Frss%3D1 (Source: Cerebral Cortex) Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5389744 Fri, 04 Nov 2011 04:00:00 +0100 5389744 http://www.medworm.com/index.php?rid=5389743&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F21%2F12%2FNP-b%3Frss%3D1 (Source: Cerebral Cortex) Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5389743 Fri, 04 Nov 2011 04:00:00 +0100 5389743 http://www.medworm.com/index.php?rid=5389742&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F21%2F12%2FNP-a%3Frss%3D1 (Source: Cerebral Cortex) Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5389742 Fri, 04 Nov 2011 04:00:00 +0100 5389742 http://www.medworm.com/index.php?rid=5389741&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F21%2F12%2FNP%3Frss%3D1 (Source: Cerebral Cortex) Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5389741 Fri, 04 Nov 2011 04:00:00 +0100 5389741 http://www.medworm.com/index.php?rid=5275545&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F21%2F11%2F2663%3Frss%3D1 (Source: Cerebral Cortex) Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5275545 Thu, 29 Sep 2011 04:00:00 +0100 5275545 http://www.medworm.com/index.php?rid=5275544&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F21%2F11%2F2650%3Frss%3D1 Goal-directed perceptual decisions involve the analysis of sensory inputs, the extraction and accumulation of evidence, and the commitment to a choice. Previous neuroimaging studies of perceptual decision making have identified activity related to accumulation in parietal, inferior temporal, and frontal regions. However, such effects may be related to factors other than the integration of evidence over time, such as changes in the quantity of stimulus input and in attentional demands leading up to a decision. The current study tested an accumulation account using 2 manipulations. First, to test whether patterns of accumulation can be explained by changes in the quantity of sensory information, objects were revealed with a high quality but consistent quantity of evidence throughout the tria... Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5275544 Thu, 29 Sep 2011 04:00:00 +0100 5275544 http://www.medworm.com/index.php?rid=5275543&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F21%2F11%2F2639%3Frss%3D1 To characterize connexin36 (Cx36)-expressing neurons of the adult rat somatosensory cortex, we examined fluorescence signals for Cx36 messenger RNA (mRNA) in 3 nonoverlapping subpopulations of -aminobutyric acid (GABA)ergic interneurons, which showed immunoreactivity for 1) parvalbumin (PV); 2) somatostatin (SOM); and 3) either calretinin (CR), vasoactive intestinal polypeptide (VIP), cholecystokinin (CCK), or choline acetyltransferase (ChAT). About 80% of PV-, 52% of SOM-, 37% of CR/VIP/CCK/ChAT-immunoreactive cells displayed Cx36 signals across all cortical layers, and inversely 64%, 25%, and 9% of Cx36-expressing neurons were positive for PV, SOM, or CR/VIP/CCK/ChAT, respectively. Notably, although almost all Cx36-expressing neurons in layer (L) 4, L5, and L6 were positive for one of th... Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5275543 Thu, 29 Sep 2011 04:00:00 +0100 5275543 http://www.medworm.com/index.php?rid=5275542&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F21%2F11%2F2620%3Frss%3D1 Primary sensory cortical responses are modulated by the presence or expectation of related sensory information in other modalities, but the sources of multimodal information and the cellular locus of this integration are unclear. We investigated the modulation of neural responses in the murine primary auditory cortical area Au1 by extrastriate visual cortex (V2). Projections from V2 to Au1 terminated in a classical descending/modulatory pattern, with highest density in layers 1, 2, 5, and 6. In brain slices, whole-cell recordings revealed long latency responses to stimulation in V2L that could modulate responses to subsequent white matter (WM) stimuli at latencies of 5–20 ms. Calcium responses imaged in Au1 cell populations showed that preceding WM with V2L stimulation modulated WM r... Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5275542 Thu, 29 Sep 2011 04:00:00 +0100 5275542 http://www.medworm.com/index.php?rid=5275541&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F21%2F11%2F2612%3Frss%3D1 Recent studies have established a relation between ongoing brain activity fluctuations and intertrial variability in evoked neural responses, perception, and motor performance. Here, we extended these investigations into the domain of cognitive control. Using functional neuroimaging and a sparse event-related design (with long and unpredictable intervals), we measured ongoing activity fluctuations and evoked responses in volunteers performing a Stroop task with color–word interference. Across trials, prestimulus activity of several regions predicted subsequent response speed and across subjects this effect scaled with the Stroop effect size, being significant only in subjects manifesting behavioral interference. These effects occurred only in task relevant as the dorsal anterior cing... Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5275541 Thu, 29 Sep 2011 04:00:00 +0100 5275541 http://www.medworm.com/index.php?rid=5275540&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F21%2F11%2F2599%3Frss%3D1 Cajal–Retzius cells are essential pioneer neurons that guide neuronal migration in the developing neocortex. During development, Cajal–Retzius cells arise from distinct progenitor domains that line the margins of the dorsal telencephalon, or pallium. Here, we show that the proneural gene Ascl1 is expressed in Cajal–Retzius cell progenitors in the pallial septum, ventral pallium, and cortical hem. Using a short-term lineage trace, we demonstrate that it is primarily the Ascl1-expressing progenitors in the pallial septum and ventral pallium that differentiate into Cajal–Retzius cells. Accordingly, we found a small, albeit significant reduction in the number of Reelin+ and Trp73+ Cajal–Retzius cells in the Ascl1–/– neocortex. Conversely, using a gain-... Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5275540 Thu, 29 Sep 2011 04:00:00 +0100 5275540 http://www.medworm.com/index.php?rid=5275539&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F21%2F11%2F2589%3Frss%3D1 Memory verification is crucial for meaningful behavior. Orbitofrontal damage may impair verification and induce confabulation and inappropriate acts. The strategic retrieval account explains this state by deficient monitoring of memories' precise content, whereas the reality filter hypothesis explains it by a failure of an orbitofrontal mechanism suppressing the interference of memories that do not pertain to reality. The distinctiveness of these mechanisms has recently been questioned. Here, we juxtaposed these 2 mechanisms using high-resolution evoked potentials in healthy subjects who performed 2 runs of a continuous recognition task which contained pictures that precisely matched or only resembled previous pictures. We found behavioral and electrophysiological dissociation: Strategic c... Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5275539 Thu, 29 Sep 2011 04:00:00 +0100 5275539 http://www.medworm.com/index.php?rid=5275538&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F21%2F11%2F2578%3Frss%3D1 Recent research showed that cognitive emotion regulation (ER) both increases activity in the dorsolateral prefrontal cortex (DLPFC) and decreases striatal responsivity to monetary rewards. Using a mixed monetary incentive delay/memory task as well as functional magnetic resonance imaging, we tested in healthy subjects whether ER effectively attenuates striatal reward encoding during the anticipation of reward (1.00 vs. 0.05 reward cues) as well as subsequent target reaction times (RTs), which are an indicator of motivation to obtain reward. ER significantly diminished feelings of pleasant anticipation and slowed down 1.00 target RT. At the neural level, ER increased activity in the DLPFC and attenuated reward encoding in the left putamen. Analyses of psychophysiological interaction reveale... Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5275538 Thu, 29 Sep 2011 04:00:00 +0100 5275538 http://www.medworm.com/index.php?rid=5275537&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F21%2F11%2F2565%3Frss%3D1 Little is currently known about the alterations in the topological organization of the white matter (WM) structural networks in patients with multiple sclerosis (MS). In the present study, we used diffusion tensor imaging and deterministic tractography to map the WM structural networks in 39 MS patients and 39 age- and gender-matched healthy controls. Graph theoretical methods were applied to investigate alterations in the network efficiency in these patients. The MS patients and the controls exhibited efficient small-world properties in their WM structural networks. However, the global and local network efficiencies were significantly decreased in the MS patients compared with the controls, with the most pronounced changes observed in the sensorimotor, visual, default-mode, and language a... Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5275537 Thu, 29 Sep 2011 04:00:00 +0100 5275537 http://www.medworm.com/index.php?rid=5275536&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F21%2F11%2F2555%3Frss%3D1 Working memory training is a useful tool to examine dissociations between specific working memory processes. Although current models propose a distinction between modality-specific working memory processes, to our knowledge no study has directly examined the effects of visual versus auditory working memory training. Functional magnetic resonance imaging was used to investigate whether visual working memory processes can be trained specifically and whether those effects can be separated from across-modal training effects. We found decidedly larger training gains after visual working memory training compared with auditory or no training on a visual 2-back task. These effects were accompanied by specific training-related decreases in the right middle frontal gyrus arising from visual training... Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5275536 Thu, 29 Sep 2011 04:00:00 +0100 5275536 http://www.medworm.com/index.php?rid=5275535&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F21%2F11%2F2542%3Frss%3D1 Neurons in primary visual cortex have been characterized by their selectivity to orientation, spatiotemporal frequencies, and motion direction, among others all essential parameters to decompose complex image structure. However, their concerted functioning upon real-world visual dynamics remained unobserved since most studies tested these parameters in isolation rather than in rich mixture. We used voltage-sensitive dye imaging to characterize population responses to natural scene movies, and for comparison, to well-established moving gratings. For the latter, we confirm previous observations of a deceleration/acceleration notch. Upon stimulation with natural movies, however, a subsequent acceleration component was almost absent. Furthermore, we found that natural stimuli revealed sparsely... Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5275535 Thu, 29 Sep 2011 04:00:00 +0100 5275535 http://www.medworm.com/index.php?rid=5275534&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F21%2F11%2F2534%3Frss%3D1 Ample evidence supports a role for sleep in the offline consolidation of memory. However, circumstances exist where forgetting can be as critical as remembering, both in daily life and clinically. Using a directed forgetting paradigm, here, we investigate the impact of explicit cue instruction during learning, prior to sleep, on subsequent remembering and forgetting of memory, after sleep. We demonstrate that sleep, relative to time awake, can selectively ignore the facilitation of items previously cued to be forgotten, yet preferentially enhance recall for items cued to be remembered; indicative of specificity based on prior waking instruction. Moreover, the success of this differential remember/forget effect is strongly correlated with fast sleep spindles over the left superior parietal ... Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5275534 Thu, 29 Sep 2011 04:00:00 +0100 5275534 http://www.medworm.com/index.php?rid=5275533&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F21%2F11%2F2525%3Frss%3D1 Gender dysphoria is suggested to be a consequence of sex atypical cerebral differentiation. We tested this hypothesis in a magnetic resonance study of voxel-based morphometry and structural volumetry in 48 heterosexual men (HeM) and women (HeW) and 24 gynephillic male to female transsexuals (MtF-TR). Specific interest was paid to gray matter (GM) and white matter (WM) fraction, hemispheric asymmetry, and volumes of the hippocampus, thalamus, caudate, and putamen. Like HeM, MtF-TR displayed larger GM volumes than HeW in the cerebellum and lingual gyrus and smaller GM and WM volumes in the precentral gyrus. Both male groups had smaller hippocampal volumes than HeW. As in HeM, but not HeW, the right cerebral hemisphere and thalamus volume was in MtF-TR lager than the left. None of these measu... Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5275533 Thu, 29 Sep 2011 04:00:00 +0100 5275533 http://www.medworm.com/index.php?rid=5275532&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F21%2F11%2F2519%3Frss%3D1 The total numbers of neurons and glial cells in the neocortex and basal ganglia in adults with Down syndrome (DS) were estimated with design-based stereological methods, providing quantitative data on brains affected by delayed development and accelerated aging. Cell numbers, volume of regions, and densities of neurons and glial cell subtypes were estimated in brains from 4 female DS subjects (mean age 66 years) and 6 female controls (mean age 70 years). The DS subjects were estimated to have about 40% fewer neocortical neurons in total (11.1 x 109 vs. 17.8 x 109, 2p ≤ 0.001) and almost 30% fewer neocortical glial cells with no overlap to controls (12.8 x 109 vs. 18.2 x 109, 2p = 0.004). In contrast, the total number of neurons in the basal ganglia was the same in the 2 groups, whereas ... Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5275532 Thu, 29 Sep 2011 04:00:00 +0100 5275532 http://www.medworm.com/index.php?rid=5275531&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F21%2F11%2F2507%3Frss%3D1 The neurophysiological basis for stuttering may involve deficits that affect dynamic interactions among neural structures supporting fluid speech processing. Here, we examined functional and structural connectivity within corticocortical and thalamocortical loops in adults who stutter. For functional connectivity, we placed seeds in the left and right inferior frontal Brodmann area 44 (BA44) and in the ventral lateral nucleus (VLN) of the thalamus. Subject-specific seeds were based on peak activation voxels captured during speech and nonspeech tasks using functional magnetic resonance imaging. Psychophysiological interaction (PPI) was used to find brain regions with heightened functional connectivity with these cortical and subcortical seeds during speech and nonspeech tasks. Probabilistic... Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5275531 Thu, 29 Sep 2011 04:00:00 +0100 5275531 http://www.medworm.com/index.php?rid=5275530&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F21%2F11%2F2498%3Frss%3D1 When exploring a visual scene, some objects perceptually popout because of a difference of color, shape, or size. This bottom-up information is an important part of many models describing the allocation of visual attention. It has been hypothesized that the lateral intraparietal area (LIP) acts as a "priority map," integrating bottom-up and top-down information to guide the allocation of attention. Despite a large literature describing top-down influences in LIP, the presence of a pure salience response to a salient stimulus defined by its static features alone has not been reported. We compared LIP responses with colored salient stimuli and distractors in a passive fixation task. Many LIP neurons responded preferentially to 1 of the 2 colored stimuli, yet the mean responses to the salient... Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5275530 Thu, 29 Sep 2011 04:00:00 +0100 5275530 http://www.medworm.com/index.php?rid=5275529&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F21%2F11%2F2482%3Frss%3D1 During natural vision, primates perform frequent saccadic eye movements, allowing only a narrow time window for processing the visual information at each location. Individual neurons may contribute only with a few spikes to the visual processing during each fixation, suggesting precise spike timing as a relevant mechanism for information processing. We recently found in V1 of monkeys freely viewing natural images, that fixation-related spike synchronization occurs at the early phase of the rate response after fixation-onset, suggesting a specific role of the first response spikes in V1. Here, we show that there are strong local field potential (LFP) modulations locked to the onset of saccades, which continue into the successive fixation periods. Visually induced spikes, in particular the f... Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5275529 Thu, 29 Sep 2011 04:00:00 +0100 5275529 http://www.medworm.com/index.php?rid=5275528&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F21%2F11%2F2471%3Frss%3D1 Turner syndrome (TS) is a genetic disorder affecting females, resulting from the complete or partial absence of an X chromosome. The cognitive profile of TS shows relative strengths in the verbal domain and weaknesses in the procedural domain, including working memory. Neuroimaging studies have identified differences in the morphology of the parietal lobes, and white matter pathways linking frontal and parietal regions, as well as abnormal activation in dorsal frontal and parietal regions. Taken together these findings suggest that abnormal functional connectivity between frontal and parietal regions may be related to working memory impairments in TS, a hypothesis we tested in the present study. We scanned TS and typically developing participants with functional magnetic resonance imaging ... Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5275528 Thu, 29 Sep 2011 04:00:00 +0100 5275528 http://www.medworm.com/index.php?rid=5275527&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F21%2F11%2F2461%3Frss%3D1 Guilt is a central moral emotion due to its inherent link to norm violations, thereby affecting both individuals and society. Furthermore, the nature and specificity of guilt is still debated in psychology and philosophy, particularly with regard to the differential involvement of self-referential representations in guilt relative to shame. Here, using functional magnetic resonance imaging (fMRI) in healthy volunteers, we identified specific brain regions associated with guilt by comparison with the 2 most closely related emotions, shame and sadness. To induce high emotional intensity, we used an autobiographical memory paradigm where participants relived during fMRI scanning situations from their own past that were associated with strong feelings of guilt, shame, or sadness. Compared with... Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5275527 Thu, 29 Sep 2011 04:00:00 +0100 5275527 http://www.medworm.com/index.php?rid=5275526&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F21%2F11%2F2450%3Frss%3D1 Subclasses of -aminobutyric acid (GABA) interneurons differentially influence cortical network activity. The contribution of differences in GABA synthesis and reuptake in axon boutons to cell type–specific functions is unknown. GABA is synthesized within boutons by glutamic acid decarboxylase 65 (GAD65) and GAD67, while GAT1 is responsible for GABA reuptake. Using an imaging methodology capable of determining the colocalization frequency of different immunocytochemical labels in the same bouton and the quantification of the fluorescence intensity of each label in these same structures, we assessed the bouton levels of GAD65, GAD67, and GAT1 in parvalbumin–expressing chandelier (PVch) and basket (PVb) neurons and cannabinoid 1 receptor–expressing basket (CB1rb) neurons in ... Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5275526 Thu, 29 Sep 2011 04:00:00 +0100 5275526 http://www.medworm.com/index.php?rid=5275525&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F21%2F11%2F2442%3Frss%3D1 We report that in freely behaving rats, long-term potentiation (LTP) is facilitated at both mossy fiber (mf)–CA3 and commissural–associational (AC)–CA3 synapses by exploration of a novel (empty) environment. Exploration of large spatial landmarks facilitates long-term depression (LTD) at mf-CA3 synapses and impairs synaptic depression at AC-CA3 synapses. Novel exploration of small environmental features does not facilitate LTD at mf synapses but facilitates persistent LTD at AC synapses. Thus, depending on the quality of the information synaptic plasticity at AC-CA3 and mf-CA3 synapses is differentially modulated. These data suggest that expression of LTP as a result of environmental change is a common property of hippocampal synapses. However, LTD at mf synapses or AC sy... Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5275525 Thu, 29 Sep 2011 04:00:00 +0100 5275525 http://www.medworm.com/index.php?rid=5275524&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F21%2F11%2F2425%3Frss%3D1 Little is known regarding the synaptic properties of corticocortical connections from one cortical area to another. To expand on this knowledge, we assessed the synaptic properties of excitatory projections from the primary to secondary auditory cortex and vice versa. We identified 2 types of postsynaptic responses. The first class of responses have larger initial excitatory postsynaptic potentials (EPSPs), exhibit paired-pulse depression, are limited to ionotropic glutamate receptor activation, and have larger synaptic terminals; the second has smaller initial EPSPs, paired-pulse facilitation, metabotropic glutamate receptor activation, and smaller synaptic terminals. These responses are similar to the driver and modulator properties previously identified for thalamic and thalamocortical ... Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5275524 Thu, 29 Sep 2011 04:00:00 +0100 5275524 http://www.medworm.com/index.php?rid=5275523&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F21%2F11%2FNP-c%3Frss%3D1 (Source: Cerebral Cortex) Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5275523 Thu, 29 Sep 2011 04:00:00 +0100 5275523 http://www.medworm.com/index.php?rid=5275522&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F21%2F11%2FNP-b%3Frss%3D1 (Source: Cerebral Cortex) Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5275522 Thu, 29 Sep 2011 04:00:00 +0100 5275522 http://www.medworm.com/index.php?rid=5275521&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F21%2F11%2FNP-a%3Frss%3D1 (Source: Cerebral Cortex) Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5275521 Thu, 29 Sep 2011 04:00:00 +0100 5275521 http://www.medworm.com/index.php?rid=5275520&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F21%2F11%2FNP%3Frss%3D1 (Source: Cerebral Cortex) Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5275520 Thu, 29 Sep 2011 04:00:00 +0100 5275520 http://www.medworm.com/index.php?rid=5211022&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F21%2F10%2F2415%3Frss%3D1 Callosal volume reduction has been observed in patients with bipolar disorder, but whether these deficits reflect genetic vulnerability to the illness remains unresolved. Here, we used computational methods to map corpus callosum abnormalities in a population-based sample of twin pairs discordant for bipolar disorder. Twenty-one probands with bipolar I disorder (mean age 44.4 ± 7.5 years; 48% female), 19 of their non-bipolar co-twins, and 34 demographically matched control twin individuals underwent magnetic resonance imaging. Three-dimensional callosal surface models were created to visualize its morphologic variability and to localize group differences. Neurocognitive correlates of callosal area differences were additionally investigated in a subsample of study participants. Bipol... Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5211022 Thu, 08 Sep 2011 04:00:00 +0100 5211022 http://www.medworm.com/index.php?rid=5211021&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F21%2F10%2F2408%3Frss%3D1 Perception is not a simple reflection of sensory information but varies within and between individuals. This applies particularly to the perception of pain, which, in the brain, is associated with neuronal responses at different frequencies. Here, we show how these different neuronal responses subserve interindividual and intraindividual variations in the perception of identical painful stimuli. A time–frequency analysis of single trial electroencephalographic data indicates that pain-related responses in the theta frequency range but not at higher gamma frequencies code for interindividual variations in the perception of pain. In contrast, both pain-related theta and gamma responses provide different and complementary information on intraindividual variations in the pain experience.... Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5211021 Thu, 08 Sep 2011 04:00:00 +0100 5211021 http://www.medworm.com/index.php?rid=5211020&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F21%2F10%2F2399%3Frss%3D1 In this study, we show that DMN functional connectivity (FC) during rest is altered with increasing levels of PIB uptake in NC. Specifically, FC decreases were identified in regions implicated in episodic memory (EM) processing (posteromedial cortex, ventral medial prefrontal cortex, and angular gyrus), whereas connectivity increases were detected in dorsal and anterior medial prefrontal and lateral temporal cortices. This pattern of decreases is consistent with previous studies that suggest heightened vulnerability of EM-related brain regions in AD, whereas the observed increases in FC may reflect a compensatory response. (Source: Cerebral Cortex) Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5211020 Thu, 08 Sep 2011 04:00:00 +0100 5211020 http://www.medworm.com/index.php?rid=5211019&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F21%2F10%2F2394%3Frss%3D1 The neural mechanisms underlying conversion disorders such as hysterical blindness are at present unknown. Typically, patients are diagnosed through exclusion of neurological disease and the absence of pathologic neurophysiological diagnostic findings. Here, we investigate the neural basis of this disorder by combining electrophysiological (event-related potentials) and hemodynamic measures (functional magnet resonance tomography) in a patient with hysterical blindness before and after successful treatment. Importantly, the blindness was limited to the left upper and right lower visual quadrant offering the possibility to use the other 2 sighted quadrants as controls. While the functional magnetic resonance imaging activations were normal for visual stimulation electrophysiological indices... Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5211019 Thu, 08 Sep 2011 04:00:00 +0100 5211019 http://www.medworm.com/index.php?rid=5211018&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F21%2F10%2F2374%3Frss%3D1 A large-scale study of 484 elementary school children (6–10 years) performing word repetition tasks in their native language (L1-Japanese) and a second language (L2-English) was conducted using functional near-infrared spectroscopy. Three factors presumably associated with cortical activation, language (L1/L2), word frequency (high/low), and hemisphere (left/right), were investigated. L1 words elicited significantly greater brain activation than L2 words, regardless of semantic knowledge, particularly in the superior/middle temporal and inferior parietal regions (angular/supramarginal gyri). The greater L1-elicited activation in these regions suggests that they are phonological loci, reflecting processes tuned to the phonology of the native language, while phonologically unfamiliar L... Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5211018 Thu, 08 Sep 2011 04:00:00 +0100 5211018 http://www.medworm.com/index.php?rid=5211017&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F21%2F10%2F2366%3Frss%3D1 The development and relapse of many psychopathologies can be linked to both stress and prefrontal cortex dysfunction. Glucocorticoid stress hormones target medial prefrontal cortex (mPFC) and either chronic stress or chronic administration of glucocorticoids produces dendritic remodeling in prefrontal pyramidal neurons. Exposure to stress also causes an increase in the release of the excitatory amino acid glutamate, which binds to N-methyl-D-aspartate (NMDA) receptors, which are plentiful in mPFC. NMDA receptor activation is crucial for producing hippocampal dendritic remodeling due to stress and for dendritic reorganization in frontal cortex after cholinergic deafferentation. Thus, NMDA receptors could mediate stress-induced dendritic retraction in mPFC. To test this hypothesis, dendritic... Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5211017 Thu, 08 Sep 2011 04:00:00 +0100 5211017 http://www.medworm.com/index.php?rid=5211016&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F21%2F10%2F2357%3Frss%3D1 Musical training is known to modify auditory perception and related cortical organization. Here, we show that these modifications may extend to higher cognitive functions and generalize to processing of speech. Previous studies have shown that adults and newborns can segment a continuous stream of linguistic and nonlinguistic stimuli based only on probabilities of occurrence between adjacent syllables or tones. In the present experiment, we used an artificial (sung) language learning design coupled with an electrophysiological approach. While behavioral results were not clear cut in showing an effect of expertise, Event-Related Potentials data showed that musicians learned better than did nonmusicians both musical and linguistic structures of the sung language. We discuss these findings in... Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5211016 Thu, 08 Sep 2011 04:00:00 +0100 5211016 http://www.medworm.com/index.php?rid=5211015&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F21%2F10%2F2348%3Frss%3D1 Correlated spontaneous activity in the resting brain is increasingly recognized as a useful index for inferring underlying functional-anatomic architecture. However, despite efforts for comparison with anatomical connectivity, neuronal origin of intrinsic functional connectivity (inFC) remains unclear. Conceptually, the source of inFC could be decomposed into causal components that reflect the efficacy of synaptic interactions and other components mediated by collective network dynamics (e.g., synchronization). To dissociate these components, it is useful to introduce another connectivity measure such as effective connectivity, which is a quantitative measure of causal interactions. Here, we present a direct comparison of inFC against emEC (effective connectivity probed with electrical mic... Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5211015 Thu, 08 Sep 2011 04:00:00 +0100 5211015 http://www.medworm.com/index.php?rid=5211014&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F21%2F10%2F2332%3Frss%3D1 To clarify speech-elicited response patterns within auditory-responsive cortex of the posterolateral superior temporal (PLST) gyrus, time–frequency analyses of event-related band power in the high gamma frequency range (75–175 Hz) were performed on the electrocorticograms recorded from high-density subdural grid electrodes in 8 patients undergoing evaluation for medically intractable epilepsy. Stimuli were 6 stop consonant–vowel (CV) syllables that varied in their consonant place of articulation (POA) and voice onset time (VOT). Initial augmentation was maximal over several centimeters of PLST, lasted about 400 ms, and was often followed by suppression and a local outward expansion of activation. Maximal gamma power overlapped either the Nα or Pβ deflections of... Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5211014 Thu, 08 Sep 2011 04:00:00 +0100 5211014 http://www.medworm.com/index.php?rid=5211013&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F21%2F10%2F2322%3Frss%3D1 In bistable vision, one constant ambiguous stimulus leads to 2 alternating conscious percepts. This perceptual switching occurs spontaneously but can also be influenced through voluntary control. Neuroimaging studies have reported that frontal regions are activated during spontaneous perceptual switches, leading some researchers to suggest that frontal regions causally induce perceptual switches. But the opposite also seems possible: frontal activations may themselves be caused by spontaneous switches. Classically implicated in attentional processes, these same regions are also candidates for the origins of voluntary control over bistable vision. Here too, it remains unknown whether frontal cortex is actually functionally relevant. It is even possible that spontaneous perceptual switches a... Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5211013 Thu, 08 Sep 2011 04:00:00 +0100 5211013 http://www.medworm.com/index.php?rid=5211012&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F21%2F10%2F2313%3Frss%3D1 Cortical surface area measures appear to be functionally relevant and distinct in etiology, development, and behavioral correlates compared with other size characteristics, such as cortical thickness. Little is known about genetic and environmental influences on individual differences in regional surface area in humans. Using a large sample of adult twins, we determined relative contributions of genes and environment on variations in regional cortical surface area as measured by magnetic resonance imaging before and after adjustment for genetic and environmental influences shared with total cortical surface area. We found high heritability for total surface area and, before adjustment, moderate heritability for regional surface areas. Compared with other lobes, heritability was higher for ... Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5211012 Thu, 08 Sep 2011 04:00:00 +0100 5211012 http://www.medworm.com/index.php?rid=5211011&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F21%2F10%2F2307%3Frss%3D1 Different cortical regions within the ventral occipitotemporal junction have been reported to show preferential responses to particular objects. Thus, it is argued that there is evidence for a left-lateralized visual word form area and a right-lateralized fusiform face area, but the unique specialization of these areas remains controversial. Words are characterized by greater power in the high spatial frequency (SF) range, whereas faces comprise a broader range of high and low frequencies. We investigated how these high-order visual association areas respond to simple sine-wave gratings that varied in SF. Using functional magnetic resonance imaging, we demonstrated lateralization of activity that was concordant with the low-level visual property of words and faces; left occipitotemporal co... Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5211011 Thu, 08 Sep 2011 04:00:00 +0100 5211011 http://www.medworm.com/index.php?rid=5211010&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F21%2F10%2F2299%3Frss%3D1 Circadian rhythms exert powerful influence on various aspects of human physiology and behavior. Here, we tested changes of human cerebral cortex excitability over the course of the day with transcranial magnetic stimulation (TMS). At different times of the day, intracortical and corticospinal excitability of the primary motor cortex (M1) was evaluated in 15 healthy subjects by TMS of left M1. While motor thresholds, short-interval intracortical inhibition and facilitation and input/output curves remained unchanged, we found that a specific form of -aminobutyric acid (GABA)–mediated intracortical inhibition, revealed by long-interval intracortical inhibition and cortical silent periods, progressively decreased during the course of the day. Additional experiments demonstrated that morn... Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5211010 Thu, 08 Sep 2011 04:00:00 +0100 5211010 http://www.medworm.com/index.php?rid=5211009&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F21%2F10%2F2291%3Frss%3D1 We investigated whether the functional connections to the primary sensorimotor cortex (SMC) at rest are abnormal in 26 patients with amyotrophic lateral sclerosis (ALS) and whether such changes are related to the corticospinal tract (CST) damage, measured using diffusion tensor magnetic resonance imaging (DT MRI). ALS patients versus controls showed a significantly increased functional connectivity between the left SMC and the right cingulate cortex, parahippocampal gyrus, and cerebellum-crus II. No right SMC connectivity changes were found. The pattern of increased functional connectivity to the left SMC was more widespread when considering only patients with no CST DT MRI abnormalities than the whole group of patients. In this patient group, functional connectivity was also increased bet... Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5211009 Thu, 08 Sep 2011 04:00:00 +0100 5211009 http://www.medworm.com/index.php?rid=5211008&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F21%2F10%2F2282%3Frss%3D1 It is clear that the steroid hormone testosterone plays an important role in the regulation of social emotional behavior, but it remains unknown which neural circuits mediate these hormonal influences in humans. We investigated the modulatory effects of endogenous testosterone on the control of social emotional behavior by applying functional magnetic resonance imaging while healthy male participants performed a social approach–avoidance task. This task operationalized social emotional behavior by having participants approach and avoid emotional faces by pulling and pushing a joystick, respectively. Affect-congruent trials mapped the automatic tendency to approach happy faces and avoid angry faces. Affect-incongruent trials required participants to override those automatic action ten... Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5211008 Thu, 08 Sep 2011 04:00:00 +0100 5211008 http://www.medworm.com/index.php?rid=5211007&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F21%2F10%2F2272%3Frss%3D1 The default mode network (DMN) comprises brain structures maximally active at rest. Disturbance of network nodes or their connections occurs with some neuropsychiatric conditions and may underlie associated dysfunction. DMN connectivity has not been examined in alcoholism, which is marked by compromised DMN nodes and impaired spatial working memory. To test whether performance would be related to DMN integrity, we examined DMN functional connectivity using functional magnetic resonance imaging (fMRI) data and graph theory analysis. We assumed that disruption of short paths between network nodes would attenuate processing efficiency. Alcoholics and controls were scanned at rest and during a spatial working memory task. At rest, the spontaneous slow fluctuations of fMRI signals in the poster... Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5211007 Thu, 08 Sep 2011 04:00:00 +0100 5211007 http://www.medworm.com/index.php?rid=5211006&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F21%2F10%2F2261%3Frss%3D1 We investigated how the microstructure of relevant white matter connections is associated with cortical responsivity and working memory (WM) performance by collecting diffusion tensor imaging and verbal WM functional magnetic resonance imaging data from 29 young adults. We measured cortical responsivity within the frontoparietal WM network as the difference in blood oxygenation level–dependent (BOLD) signal between 3-back and 1-back conditions. Fractional anisotropy served as an index of the integrity of the superior longitudinal fasciculi (SLF), which connect frontal and posterior regions. We found that SLF integrity is associated with better 3-back performance and greater task-related BOLD responsivity. In addition, BOLD responsivity in right premotor cortex reliably mediated the e... Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5211006 Thu, 08 Sep 2011 04:00:00 +0100 5211006 http://www.medworm.com/index.php?rid=5211005&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F21%2F10%2F2244%3Frss%3D1 Pyramidal cells in layers 2 and 3 of the neocortex of many species collectively form a clustered system of lateral axonal projections (the superficial patch system—Lund JS, Angelucci A, Bressloff PC. 2003. Anatomical substrates for functional columns in macaque monkey primary visual cortex. Cereb Cortex. 13:15–24. or daisy architecture—Douglas RJ, Martin KAC. 2004. Neuronal circuits of the neocortex. Annu Rev Neurosci. 27:419–451.), but the function performed by this general feature of the cortical architecture remains obscure. By comparing the spatial configuration of labeled patches with the configuration of responses to drifting grating stimuli, we found the spatial organizations both of the patch system and of the cortical response to be highly conserved between... Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5211005 Thu, 08 Sep 2011 04:00:00 +0100 5211005 http://www.medworm.com/index.php?rid=5211004&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F21%2F10%2F2233%3Frss%3D1 Growing consensus suggests that autism spectrum disorders (ASD) are associated with atypical brain networks, thus shifting the focus to the study of connectivity. Many functional connectivity studies have reported underconnectivity in ASD, but results in others have been divergent. We conducted a survey of 32 functional connectivity magnetic resonance imaging studies of ASD for numerous methodological variables to distinguish studies supporting general underconnectivity (GU) from those not consistent with this hypothesis (NGU). Distinguishing patterns were apparent for several data analysis choices. The study types differed significantly with respect to low-pass filtering, task regression, and whole-brain field of view. GU studies were more likely to examine task-driven time series in regi... Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5211004 Thu, 08 Sep 2011 04:00:00 +0100 5211004 http://www.medworm.com/index.php?rid=5211003&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F21%2F10%2F2217%3Frss%3D1 Mechanisms inducing perforation of the postsynaptic density (PSD) are poorly understood. We show that neural cell adhesion molecule– deficient (NCAM–/–) hippocampal neurons have an abnormally high percentage of synapses with perforated PSDs. The percentage of synapses with perforated PSDs is also increased in wild-type (NCAM+/+) neurons after the disruption of the NCAM/spectrin complex indicating that the NCAM-assembled spectrin cytoskeleton maintains the structural integrity of PSDs. We demonstrate that PSD perforations contain endocytic zones involved in α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR) internalization. Induction of long-term potentiation in NCAM+/+ neurons accompanied by insertion of AMPAR into the neuronal cell surface is sub... Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5211003 Thu, 08 Sep 2011 04:00:00 +0100 5211003 http://www.medworm.com/index.php?rid=5211002&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F21%2F10%2F2204%3Frss%3D1 Markers of preparatory visual–spatial attention in sensory cortex have been described both as lateralized, slow-wave event-related potential (ERP) components and as lateralized changes in oscillatory-electroencephalography alpha power, but the roles of these markers and their functional relationship are still unclear. Here, 3 versions of a visual–spatial cueing paradigm, differing in perceptual task difficulty and/or response instructions, were used to investigate the functional relationships between posterior oscillatory-alpha changes and our previously reported posterior, slow-wave biasing-related negativity (swBRN) ERP activity. The results indicate that the swBRN reflects spatially specific, pretarget preparatory activity sensitive to the expected perceptual difficulty of t... Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5211002 Thu, 08 Sep 2011 04:00:00 +0100 5211002 http://www.medworm.com/index.php?rid=5211001&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F21%2F10%2F2187%3Frss%3D1 We examined the subplate with murine markers including nuclear receptor related 1 (Nurr1), monooxygenase Dbh-like 1 (Moxd1), transmembrane protein 163 (Tmem163), and connective tissue growth factor (Ctgf) in developing and adult turtle, chick, opossum, mouse, and rat. Whereas some of these are expressed in dorsal pallium in all species studied (Nurr1, Ctgf, and Tmem163), we observed that the closely related mouse and rat differed in the expression patterns of several others (Dopa decarboxylase, Moxd1, and thyrotropin-releasing hormone). The expression of Ctgf, Moxd1, and Nurr1 in the oppossum suggests a more dispersed subplate population in this marsupial compared with mice and rats. In embryonic and adult chick brains, our selected subplate markers are primarily expressed in the hyperpall... Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5211001 Thu, 08 Sep 2011 04:00:00 +0100 5211001 http://www.medworm.com/index.php?rid=5211000&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F21%2F10%2FNP-c%3Frss%3D1 (Source: Cerebral Cortex) Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5211000 Thu, 08 Sep 2011 04:00:00 +0100 5211000 http://www.medworm.com/index.php?rid=5210999&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F21%2F10%2FNP-b%3Frss%3D1 (Source: Cerebral Cortex) Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5210999 Thu, 08 Sep 2011 04:00:00 +0100 5210999 http://www.medworm.com/index.php?rid=5210998&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F21%2F10%2FNP-a%3Frss%3D1 (Source: Cerebral Cortex) Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5210998 Thu, 08 Sep 2011 04:00:00 +0100 5210998 http://www.medworm.com/index.php?rid=5210997&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F21%2F10%2FNP%3Frss%3D1 (Source: Cerebral Cortex) Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5210997 Thu, 08 Sep 2011 04:00:00 +0100 5210997 http://www.medworm.com/index.php?rid=5127002&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F21%2F9%2F2177%3Frss%3D1 The mechanisms by which transcription factors control stepwise lineage restriction during the specification of cortical neurons remain largely unknown. Here, we investigated the role of forebrain embryonic zinc finger like (Fezf2) in this process by generating Fezf2 knockdown and tetracycline-inducible Fezf2 overexpression mouse embryonic stem cell (mESC) lines. The overexpression of Fezf2 at early time points significantly increased the generation of rostral forebrain progenitors (Foxg1+, Six3+) and inhibited the expression of transcription factors which are expressed by the midbrain and caudal diencephalon (En1+, Irx+). This effect was partially achieved by the regulation of Wnt signaling during this critical early time window. The role of Fezf2 in regulating the rostrocaudal patterning ... Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5127002 Thu, 11 Aug 2011 23:00:00 +0100 5127002 http://www.medworm.com/index.php?rid=5127001&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F21%2F9%2F2166%3Frss%3D1 This functional magnetic resonance imaging study investigated the relationship between the neural correlates of associative memory encoding, callosal integrity, and memory performance in older adults. Thirty-six older and 18 young subjects were scanned while making relational judgments on word pairs. Neural correlates of successful encoding (subsequent memory effects) were identified by contrasting the activity elicited by study pairs that were correctly identified as having been studied together with the activity elicited by pairs wrongly judged to have come from different study trials. Subsequent memory effects common to the 2 age groups were identified in several regions, including left inferior frontal gyrus and bilateral hippocampus. Negative effects (greater activity for forgotten th... Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5127001 Thu, 11 Aug 2011 23:00:00 +0100 5127001 http://www.medworm.com/index.php?rid=5127000&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F21%2F9%2F2158%3Frss%3D1 Neuron-restrictive silencer factor (NRSF), also known as repressor element-1 silencing transcription factor, is a transcriptional repressor that plays important roles in embryonic development and neurogenesis. Recent findings show that NRSF is upregulated after seizures activity however, the link between NRSF and epileptogenesis remains poorly understood. To investigate the role of NRSF in epilepsy, we employed a Cre–loxp system to specifically delete NRSF in excitatory neurons of the postnatal mouse forebrain. In the kindling model of epileptogenesis, conditional NRSF knockout (NRSF-cKO) mice exhibited dramatically accelerated seizure progression and prolonged afterdischarge duration compared with control mice. Moreover, seizures activity–induced mossy fiber sprouting was enha... Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5127000 Thu, 11 Aug 2011 23:00:00 +0100 5127000 http://www.medworm.com/index.php?rid=5126999&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F21%2F9%2F2147%3Frss%3D1 Temporal lobe epilepsy (TLE) is the most common drug-resistant epilepsy in adults. As morphometric studies have shown widespread structural damage in TLE, this condition is often referred to as a system disorder with disrupted structural networks. Studies based on univariate statistical comparisons can only indirectly test such hypothesis. Graph theory provides a new approach to formally analyze large-scale networks. Using graph-theoretical analysis of magnetic resonance imaging–based cortical thickness correlations, we investigated the structural basis of the organization of such networks in 122 TLE patients and 47 age- and sex-matched healthy controls. Networks in patients and controls were characterized by a short path length between anatomical regions and a high degree of cluster... Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5126999 Thu, 11 Aug 2011 23:00:00 +0100 5126999 http://www.medworm.com/index.php?rid=5126998&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F21%2F9%2F2133%3Frss%3D1 In conclusion, this study supports an important cross-modal component in reorganization of adult mouse visual cortex upon monocular enucleation. (Source: Cerebral Cortex) Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5126998 Thu, 11 Aug 2011 23:00:00 +0100 5126998 http://www.medworm.com/index.php?rid=5126997&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F21%2F9%2F2122%3Frss%3D1 This study aimed to assess basic and higher-order visual deficits in 21 PCA patients. Basic visual skills including form detection and discrimination, color discrimination, motion coherence, and point localization were measured, and associations and dissociations between specific basic visual functions and measures of higher-order object and space perception were identified. All participants showed impairment in at least one aspect of basic visual processing. However, a number of dissociations between basic visual skills indicated a heterogeneous pattern of visual impairment among the PCA patients. Furthermore, basic visual impairments were associated with particular higher-order object and space perception deficits, but not with nonvisual parietal tasks, suggesting the specific involvemen... Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5126997 Thu, 11 Aug 2011 23:00:00 +0100 5126997 http://www.medworm.com/index.php?rid=5126996&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F21%2F9%2F2113%3Frss%3D1 There is increasing evidence to suggest that primary sensory cortices can become active in the absence of external stimulation in their respective modalities. This occurs, for example, when stimuli processed via one sensory modality imply features characteristic of a different modality; for instance, visual stimuli that imply touch have been observed to activate the primary somatosensory cortex (SI). In the present study, we addressed the question of whether such cross-modal activations are content specific. To this end, we investigated neural activity in the primary somatosensory cortex of subjects who observed human hands engaged in the haptic exploration of different everyday objects. Using multivariate pattern analysis of functional magnetic resonance imaging data, we were able to pred... Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5126996 Thu, 11 Aug 2011 23:00:00 +0100 5126996 http://www.medworm.com/index.php?rid=5126995&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F21%2F9%2F2103%3Frss%3D1 The role of anterior temporal lobes (ATLs) in semantic processing is controversial. One theory, influenced by semantic dementia (SD) patients, is that this region is a pan-modal hub for all concepts. An alternative view is that atrophy in SD specifically affects knowledge for visual features. This is supported by reports of reverse concreteness effects in a few SD patients, suggesting that abstract word knowledge is spared relative to concrete words. However, it is not clear whether such effects are typical in SD, hence reliably associated with ATL damage, because most reports are of single cases and group studies have produced conflicting results. To address these contradictions, we investigated concreteness effects in 7 SD patients, using multiple tests from earlier studies in addition t... Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5126995 Thu, 11 Aug 2011 23:00:00 +0100 5126995 http://www.medworm.com/index.php?rid=5126994&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F21%2F9%2F2094%3Frss%3D1 To explore visual scenes in the everyday world, we constantly move our eyes, yet most neural studies of scene processing are conducted with the eyes held fixated. Such prior work in humans suggests that the parahippocampal place area (PPA) represents scenes in a highly specific manner that can differentiate between different but overlapping views of a panoramic scene. Using functional magnetic resonance imaging (fMRI) adaptation to measure sensitivity to change, we asked how this specificity is affected when active eye movements across a stable scene generate retinotopically different views. The PPA adapted to successive views when subjects made a series of saccades across a stationary spatiotopic scene but not when the eyes remained fixed and a scene translated in the background, suggesti... Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5126994 Thu, 11 Aug 2011 23:00:00 +0100 5126994 http://www.medworm.com/index.php?rid=5126993&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F21%2F9%2F2082%3Frss%3D1 Falling asleep is paralleled by a loss of conscious awareness and reduced capacity to process external stimuli. Little is known on sleep-associated changes of spontaneously synchronized anatomical networks as detected by resting-state functional magnetic resonance imaging (rs-fMRI). We employed functional connectivity analysis of rs-fMRI series obtained from 25 healthy participants, covering all non-rapid eye movement (NREM) sleep stages. We focused on the default mode network (DMN) and its anticorrelated network (ACN) that are involved in internal and external awareness during wakefulness. Using independent component analysis, cross-correlation analysis (CCA), and intraindividual dynamic network tracking, we found significant changes in DMN/ACN integrity throughout the NREM sleep. With in... Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5126993 Thu, 11 Aug 2011 23:00:00 +0100 5126993 http://www.medworm.com/index.php?rid=5126992&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F21%2F9%2F2075%3Frss%3D1 The primary visual cortex V1, when dissected, is characterized by an easily identifiable anatomical landmark: the stria of Gennari or Gennari stripe. However, the origin and function of the Gennari stripe is so far unknown. In order to shed some light on this question, we acquired 7-T magnetic resonance imaging (MRI) brain scans of congenitally blind (CB) people, who have never had visual experience. If the stria of Gennari requires visual input to develop or to maintain its homeostasis, such subjects should lack this structure. If it is reliably detectable in the CB, it must form and persist independently of visual sensation. This question has never previously been explored in living subjects. For the first time, the use of 7-T high-resolution MRI enables such investigations because of th... Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5126992 Thu, 11 Aug 2011 23:00:00 +0100 5126992 http://www.medworm.com/index.php?rid=5126991&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F21%2F9%2F2065%3Frss%3D1 Early -aminobutyric acid mediated (GABAergic) synaptic transmission and correlated neuronal activity are fundamental to network formation; however, their regulation during early postnatal development is poorly understood. Nitric oxide (NO) is an important retrograde messenger at glutamatergic synapses, and it was recently shown to play an important role also at GABAergic synapses in the adult brain. The subcellular localization and network effect of this signaling pathway during early development are so far unexplored, but its disruption at this early age is known to lead to profound morphological and functional alterations. Here, we provide functional evidence—using whole-cell recording—that NO signaling modulates not only glutamatergic but also GABAergic synaptic transmission... Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5126991 Thu, 11 Aug 2011 23:00:00 +0100 5126991 http://www.medworm.com/index.php?rid=5126990&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F21%2F9%2F2056%3Frss%3D1 Many changes produced by chronic stress are similar to those seen in cannabinoid CB1 receptor–deficient mice. In the current study, we examined both anxiety-like behavior and dendritic complexity within the prefrontal cortex and basolateral amygdala (BLA) in wild-type and CB1 receptor–deficient mice, under basal conditions and following exposure to 21 days of protracted restraint stress. CB1 receptor–deficient mice exhibited increased indices of anxiety in the elevated plus maze under basal conditions that were similar in magnitude to changes seen in wild-type mice exposed to chronic stress. Chronic stress or deletion of the CB1 receptor also produced a reduction in both apical dendritic length and branch points of neurons within layer II/III of the prelimbic region of th... Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5126990 Thu, 11 Aug 2011 23:00:00 +0100 5126990 http://www.medworm.com/index.php?rid=5126989&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F21%2F9%2F2046%3Frss%3D1 In this study, we have explored whether cannabinoid receptors are involved in the effects of estradiol on reactive astroglia. To test this hypothesis, the effects of estradiol, the cannabinoid CB1 antagonist/inverse agonist AM251, and the cannabinoid CB2 antagonist/inverse agonist AM630 were assessed in the cerebral cortex of male rats after a stab wound brain injury. Estradiol reduced the number of vimentin immunoreactive astrocytes and the number of glial fibrillary acidic protein immunoreactive astrocytes in the proximity of the wound. The effect of estradiol was significantly inhibited by the administration of either CB1 or CB2 receptor antagonists. The effect of estradiol may be in part mediated by alterations in endocannabinoid signaling because the hormone increased in the injured c... Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5126989 Thu, 11 Aug 2011 23:00:00 +0100 5126989 http://www.medworm.com/index.php?rid=5126988&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F21%2F9%2F2033%3Frss%3D1 Amblyopia, a developmental disorder of spatial vision, is thought to result from a cascade of cortical deficits over several processing stages beginning at the primary visual cortex (V1). However, beyond V1, little is known about how cortical development limits the visual performance of amblyopic primates. We quantitatively analyzed the monocular and binocular responses of V1 and V2 neurons in a group of strabismic monkeys exhibiting varying depths of amblyopia. Unlike in V1, the relative effectiveness of the affected eye to drive V2 neurons was drastically reduced in the amblyopic monkeys. The spatial resolution and the orientation bias of V2, but not V1, neurons were subnormal for the affected eyes. Binocular suppression was robust in both cortical areas, and the magnitude of suppression... Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5126988 Thu, 11 Aug 2011 23:00:00 +0100 5126988 http://www.medworm.com/index.php?rid=5126987&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F21%2F9%2F2023%3Frss%3D1 In this study, we demonstrate marked age-related D1 receptor losses in striatal, limbic, and cortical areas using positron emission tomography and the radioligand [11C]SCH23390 in humans. Interregional correlations of binding potential (BP) values were high for areas within DA pathways in younger and elderly adults alike. Furthermore, interregional correlations in D1 BP between DA pathways were uniformly high in younger adults, indicating that D1 receptor densities in striatal, limbic, and cortical areas are not regulated independently, despite dopaminergic innervation from different midbrain areas. For elderly adults, between-pathway correlations of D1 receptor densities were preserved only between mesolimbic and mesocortical areas, whereas striatal BPs were weakly related to those in lim... Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5126987 Thu, 11 Aug 2011 23:00:00 +0100 5126987 http://www.medworm.com/index.php?rid=5126986&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F21%2F9%2F2014%3Frss%3D1 The magnitude of somatosensory evoked potentials (SEPs) elicited by simultaneous electrical stimulation of adjacent digits is generally less than the sum of potentials evoked by stimulation of each digit individually. This under-additivity suggests suppression between representations of adjacent skin regions and may reflect a process of lateral inhibition by interneurons in somatosensory cortex. Given that simply viewing the body enhances tactile acuity and that tactile acuity depends on cortical lateral inhibition, we investigated how viewing the body modulates suppressive interactions between simultaneous afferent volleys from adjacent fingers. We recorded SEPs evoked by electrical stimulation of the right index and middle fingers, either individually or simultaneously, while participant... Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5126986 Thu, 11 Aug 2011 23:00:00 +0100 5126986 http://www.medworm.com/index.php?rid=5126985&cid=s_32202_25_f&fid=32202&url=http%3A%2F%2Fcercor.oxfordjournals.org%2Fcgi%2Fcontent%2Fshort%2F21%2F9%2F2003%3Frss%3D1 Functional networks are usually accessed with "resting-state" functional magnetic resonance imaging using preselected "seeds" regions. Frequently, however, the selection of the seed locations is arbitrary. Recently, we proposed local functional connectivity density mapping (FCDM), an ultrafast data-driven to locate highly connected brain regions (functional hubs). Here, we used the functional hubs obtained from local FCDM to determine the functional networks of the resting state in 979 healthy subjects without a priori hypotheses on seed locations. In addition, we computed the global functional connectivity hubs. Seven networks covering 80% of the gray matter volume were identified. Four major cortical hubs (ventral precuneus/posterior cingulate, inferior parietal cortex, cuneus, and postc... Cerebral Cortex journals http://www.medworm.com/rss/comments.php?id=5126985 Thu, 11 Aug 2011 23:00:00 +0100 5126985