Subregional Mesiotemporal Network Topology Is Altered in Temporal Lobe Epilepsy
Temporal lobe epilepsy (TLE) is the most frequent drug-resistant epilepsy in adults and commonly associated with variable degrees of mesiotemporal atrophy on magnetic resonance imaging (MRI). Analyses of inter-regional connectivity have unveiled disruptions in large-scale cortico-cortical networks; little is known about the topological organization of the mesiotemporal lobe, the limbic subnetwork central to the disorder. We generated covariance networks based on high-resolution MRI surface-shape descriptors of the hippocampus, entorhinal cortex, and amygdala in 134 TLE patients and 45 age- and sex-matched controls. Graph-t...
Source: Cerebral Cortex - June 7, 2016 Category: Neurology Authors: Bernhardt, B. C., Bernasconi, N., Hong, S.-J., Dery, S., Bernasconi, A. Tags: Articles Source Type: research
Proper Level of Cytosolic Disabled-1, Which Is Regulated by Dual Nuclear Translocation Pathways, Is Important for Cortical Neuronal Migration
In this study, we found that Dab1 has an additional unidentified NLS, and that the Dab1 NLS1 mutant could translocate to the nucleus in an unconventional ATP/temperature-dependent and cytoplasmic factor/RanGTP gradient-independent manner. Additional mutations in the NLS1 mutant revealed that K67 and K69 are important for the nuclear transport. Furthermore, an excess of the intracellular domain of the Reelin receptors inhibited the nuclear translocation of Dab1. An in utero electroporation study showed that a large amount of Dab1 in the cytoplasm in migrating neurons inhibited the migration, and that forced transport of Dab...
Source: Cerebral Cortex - June 7, 2016 Category: Neurology Authors: Honda, T., Nakajima, K. Tags: Articles Source Type: research
Early Cerebellar Network Shifting in Spinocerebellar Ataxia Type 6
Spinocerebellar ataxia 6 (SCA6), an autosomal dominant degenerative disease, is characterized by diplopia, gait ataxia, and incoordination due to severe progressive degeneration of Purkinje cells in the vestibulo- and spinocerebellum. Ocular motor deficits are common, including difficulty fixating on moving objects, nystagmus and disruption of smooth pursuit movements. In presymptomatic SCA6, there are alterations in saccades and smooth-pursuit movements. We sought to assess functional and structural changes in cerebellar connectivity associated with a visual task, hypothesizing that gradual changes would parallel disease ...
Source: Cerebral Cortex - June 7, 2016 Category: Neurology Authors: Falcon, M. I., Gomez, C. M., Chen, E. E., Shereen, A., Solodkin, A. Tags: Articles Source Type: research
Neuroanatomical Evidence in Support of the Bilingual Advantage Theory
The "bilingual advantage" theory stipulates that constant selection and suppression between 2 languages results in enhanced executive control (EC). Behavioral studies of EC in bilinguals have employed wide-ranging tasks and report some conflicting results. To avoid concerns about tasks, we employed a different approach, measuring gray matter volume (GMV) in adult bilinguals, reasoning that any EC-associated benefits should manifest as relatively greater frontal GMV. Indeed, Spanish-English-speaking bilinguals exhibited greater bilateral frontal GMV compared with English-speaking monolinguals. Was this observation attributa...
Source: Cerebral Cortex - June 7, 2016 Category: Neurology Authors: Olulade, O. A., Jamal, N. I., Koo, D. S., Perfetti, C. A., LaSasso, C., Eden, G. F. Tags: Articles Source Type: research
Remapping, Spatial Stability, and Temporal Continuity: From the Pre-Saccadic to Postsaccadic Representation of Visual Space in LIP
As our eyes move, we have a strong percept that the world is stable in space and time; however, the signals in cortex coming from the retina change with each eye movement. It is not known how this changing input produces the visual percept we experience, although the predictive remapping of receptive fields has been described as a likely candidate. To explain how remapping accounts for perceptual stability, we examined responses of neurons in the lateral intraparietal area while animals performed a visual foraging task. When a stimulus was brought into the response field of a neuron that exhibited remapping, the onset of t...
Source: Cerebral Cortex - June 7, 2016 Category: Neurology Authors: Mirpour, K., Bisley, J. W. Tags: Articles Source Type: research
Separate Brain Circuits Support Integrative and Semantic Priming in the Human Language System
Semantic priming is a crucial phenomenon to study the organization of semantic memory. A novel type of priming effect, integrative priming, has been identified behaviorally, whereby a prime word facilitates recognition of a target word when the 2 concepts can be combined to form a unitary representation. We used both functional and anatomical imaging approaches to investigate the neural substrates supporting such integrative priming, and compare them with those in semantic priming. Similar behavioral priming effects for both semantic (Bread–Cake) and integrative conditions (Cherry–Cake) were observed when compa...
Source: Cerebral Cortex - June 7, 2016 Category: Neurology Authors: Feng, G., Chen, Q., Zhu, Z., Wang, S. Tags: Articles Source Type: research
Distinct but Overlapping Patterns of Response to Words and Faces in the Fusiform Gyrus
Converging evidence suggests that the fusiform gyrus is involved in the processing of both faces and words. We used fMRI to investigate the extent to which the representation of words and faces in this region of the brain is based on a common neural representation. In Experiment 1, a univariate analysis revealed regions in the fusiform gyrus that were only selective for faces and other regions that were only selective for words. However, we also found regions that showed both word-selective and face-selective responses, particularly in the left hemisphere. We then used a multivariate analysis to measure the pattern of resp...
Source: Cerebral Cortex - June 7, 2016 Category: Neurology Authors: Harris, R. J., Rice, G. E., Young, A. W., Andrews, T. J. Tags: Articles Source Type: research
Expecting to See a Letter: Alpha Oscillations as Carriers of Top-Down Sensory Predictions
Predictions strongly influence perception. However, the neurophysiological processes that implement predictions remain underexplored. It has been proposed that high- and low-frequency neuronal oscillations act as carriers of sensory evidence and top-down predictions, respectively (von Stein and Sarnthein 2000; Bastos et al. 2012). However, evidence for the latter hypothesis remains scarce. In particular, it remains to be shown whether slow prestimulus alpha oscillations in task-relevant brain regions are stronger in the presence of predictions, whether they influence early categorization processes, and whether this interpl...
Source: Cerebral Cortex - June 7, 2016 Category: Neurology Authors: Mayer, A., Schwiedrzik, C. M., Wibral, M., Singer, W., Melloni, L. Tags: Articles Source Type: research
Development of Tool Representations in the Dorsal and Ventral Visual Object Processing Pathways
Tools represent a special class of objects, because they are processed across both the dorsal and ventral visual object processing pathways. Three core regions are known to be involved in tool processing: the left posterior middle temporal gyrus, the medial fusiform gyrus (bilaterally), and the left inferior parietal lobule. A critical and relatively unexplored issue concerns whether, in development, tool preferences emerge at the same time and to a similar degree across all regions of the tool-processing network. To test this issue, we used functional magnetic resonance imaging to measure the neural amplitude, peak locati...
Source: Cerebral Cortex - June 7, 2016 Category: Neurology Authors: Kersey, A. J., Clark, T. S., Lussier, C. A., Mahon, B. Z., Cantlon, J. F. Tags: Articles Source Type: research
Dissociation of Neural Networks for Predisposition and for Training-Related Plasticity in Auditory-Motor Learning
Skill learning results in changes to brain function, but at the same time individuals strongly differ in their abilities to learn specific skills. Using a 6-week piano-training protocol and pre- and post-fMRI of melody perception and imagery in adults, we dissociate learning-related patterns of neural activity from pre-training activity that predicts learning rates. Fronto-parietal and cerebellar areas related to storage of newly learned auditory-motor associations increased their response following training; in contrast, pre-training activity in areas related to stimulus encoding and motor control, including right auditor...
Source: Cerebral Cortex - June 7, 2016 Category: Neurology Authors: Herholz, S. C., Coffey, E. B. J., Pantev, C., Zatorre, R. J. Tags: Articles Source Type: research
Brain Network Reconfiguration and Perceptual Decoupling During an Absorptive State of Consciousness
Trance is an absorptive state of consciousness characterized by narrowed awareness of external surroundings and has long been used—for example, by shamans—to gain insight. Shamans across cultures often induce trance by listening to rhythmic drumming. Using functional magnetic resonance imaging (fMRI), we examined the brain-network configuration associated with trance. Experienced shamanic practitioners (n = 15) listened to rhythmic drumming, and either entered a trance state or remained in a nontrance state during 8-min scans. We analyzed changes in network connectivity. Trance was associated with higher eigenv...
Source: Cerebral Cortex - June 7, 2016 Category: Neurology Authors: Hove, M. J., Stelzer, J., Nierhaus, T., Thiel, S. D., Gundlach, C., Margulies, D. S., Van Dijk, K. R. A., Turner, R., Keller, P. E., Merker, B. Tags: Articles Source Type: research
Corticostriate Projections from Areas of the "Lateral Grasping Network": Evidence for Multiple Hand-Related Input Channels
Corticostriatal projections from the primate cortical motor areas partially overlap in different zones of a large postcommissural putaminal sector designated as "motor" putamen. These zones are at the origin of parallel basal ganglia-thalamocortical subloops involved in modulating the cortical motor output. However, it is still largely unknown how parietal and prefrontal areas, connected to premotor areas, and involved in controlling higher order aspects of motor control, project to the basal ganglia. Based on tracer injections at the cortical level, we analyzed the corticostriatal projections of the macaque hand-related v...
Source: Cerebral Cortex - June 7, 2016 Category: Neurology Authors: Gerbella, M., Borra, E., Mangiaracina, C., Rozzi, S., Luppino, G. Tags: Articles Source Type: research
Prenatal Alcohol Exposure is Associated with Regionally Thinner Cortex During the Preadolescent Period
Children with fetal alcohol spectrum disorders (FASD) may exhibit craniofacial dysmorphology, neurobehavioral deficits, and reduced brain volume. Studies of cortical thickness in FASD have yielded contradictory findings, with 3 reporting thicker cerebral cortex in frontal and temporal brain regions and 2 showing thinner cortex across multiple regions. All 5 studies included subjects spanning a broad age range, and none have examined continuous measures of prenatal alcohol exposure. We investigated the relation of extent of in utero alcohol exposure to cortical thickness in 78 preadolescent children with FASD and controls w...
Source: Cerebral Cortex - June 7, 2016 Category: Neurology Authors: Robertson, F. C., Narr, K. L., Molteno, C. D., Jacobson, J. L., Jacobson, S. W., Meintjes, E. M. Tags: Articles Source Type: research
There's Waldo! A Normalization Model of Visual Search Predicts Single-Trial Human Fixations in an Object Search Task
When searching for an object in a scene, how does the brain decide where to look next? Visual search theories suggest the existence of a global "priority map" that integrates bottom-up visual information with top-down, target-specific signals. We propose a mechanistic model of visual search that is consistent with recent neurophysiological evidence, can localize targets in cluttered images, and predicts single-trial behavior in a search task. This model posits that a high-level retinotopic area selective for shape features receives global, target-specific modulation and implements local normalization through divisive inhib...
Source: Cerebral Cortex - June 7, 2016 Category: Neurology Authors: Miconi, T., Groomes, L., Kreiman, G. Tags: Articles Source Type: research
Addressing a Paradox: Dual Strategies for Creative Performance in Introspective and Extrospective Networks
Neuroimaging studies of internally generated behaviors have shown seemingly paradoxical results regarding the dorsolateral prefrontal cortex (DLPFC), which has been found to activate, not activate or even deactivate relative to control conditions. On the one hand, the DLPFC has been argued to exert top–down control over generative thought by inhibiting habitual responses; on the other hand, a deactivation and concomitant decrease in monitoring and focused attention has been suggested to facilitate spontaneous associations and novel insights. Here, we demonstrate that prefrontal engagement in creative cognition depend...
Source: Cerebral Cortex - June 7, 2016 Category: Neurology Authors: Pinho, A. L., Ullen, F., Castelo-Branco, M., Fransson, P., de Manzano, O. Tags: Articles Source Type: research
