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(Source: Cerebral Cortex)
Source: Cerebral Cortex - February 6, 2016 Category: Neurology Tags: Cover/Standing Material Source Type: research
The Regulation of Corticofugal Fiber Targeting by Retinal Inputs
Corticothalamic projection systems arise from 2 main cortical layers. Layer V neurons project exclusively to higher-order thalamic nuclei, while layer VIa fibers project to both first-order and higher-order thalamic nuclei. During early postnatal development, layer VIa and VIb fibers accumulate at the borders of the dorsal lateral geniculate nucleus (dLGN) before they innervate it. After neonatal monocular enucleation or silencing of the early retinal activity, there is premature entry of layer VIa and VIb fibers into the dLGN contralateral to the manipulation. Layer V fibers do not innervate the superficial gray layer of ...
Source: Cerebral Cortex - February 2, 2016 Category: Neurology Authors: Grant, E., Hoerder-Suabedissen, A., Molnar, Z. Tags: Original Articles Source Type: research
Reinforcement of the Brain's Rich-Club Architecture Following Early Neurodevelopmental Disruption Caused by Very Preterm Birth
The second half of pregnancy is a crucial period for the development of structural brain connectivity, and an abrupt interruption of the typical processes of development during this phase caused by the very preterm birth (<33 weeks of gestation) is likely to result in long-lasting consequences. We used structural and diffusion imaging data to reconstruct the brain structural connectome in very preterm-born adults. We assessed its rich-club organization and modularity as 2 characteristics reflecting the capacity to support global and local information exchange, respectively. Our results suggest that the establishment of ...
Source: Cerebral Cortex - February 2, 2016 Category: Neurology Authors: Karolis, V. R., Froudist-Walsh, S., Brittain, P. J., Kroll, J., Ball, G., Edwards, A. D., Dell'Acqua, F., Williams, S. C., Murray, R. M., Nosarti, C. Tags: Original Articles Source Type: research
Evidence for a Caregiving Instinct: Rapid Differentiation of Infant from Adult Vocalizations Using Magnetoencephalography
Crying is the most salient vocal signal of distress. The cries of a newborn infant alert adult listeners and often elicit caregiving behavior. For the parent, rapid responding to an infant in distress is an adaptive behavior, functioning to ensure offspring survival. The ability to react rapidly requires quick recognition and evaluation of stimuli followed by a co-ordinated motor response. Previous neuroimaging research has demonstrated early specialized activity in response to infant faces. Using magnetoencephalography, we found similarly early (100–200 ms) differences in neural responses to infant and adult cry voc...
Source: Cerebral Cortex - February 2, 2016 Category: Neurology Authors: Young, K. S., Parsons, C. E., Jegindoe Elmholdt, E.-M., Woolrich, M. W., van Hartevelt, T. J., Stevner, A. B. A., Stein, A., Kringelbach, M. L. Tags: Original Articles Source Type: research
Auditory Spatial Coding Flexibly Recruits Anterior, but Not Posterior, Visuotopic Parietal Cortex
Audition and vision both convey spatial information about the environment, but much less is known about mechanisms of auditory spatial cognition than visual spatial cognition. Human cortex contains >20 visuospatial map representations but no reported auditory spatial maps. The intraparietal sulcus (IPS) contains several of these visuospatial maps, which support visuospatial attention and short-term memory (STM). Neuroimaging studies also demonstrate that parietal cortex is activated during auditory spatial attention and working memory tasks, but prior work has not demonstrated that auditory activation occurs within visu...
Source: Cerebral Cortex - February 2, 2016 Category: Neurology Authors: Michalka, S. W., Rosen, M. L., Kong, L., Shinn-Cunningham, B. G., Somers, D. C. Tags: Original Articles Source Type: research
Local GABA Concentration Predicts Perceptual Improvements After Repetitive Sensory Stimulation in Humans
Learning mechanisms are based on synaptic plasticity processes. Numerous studies on synaptic plasticity suggest that the regulation of the inhibitory neurotransmitter -aminobutyric acid (GABA) plays a central role maintaining the delicate balance of inhibition and excitation. However, in humans, a link between learning outcome and GABA levels has not been shown so far. Using magnetic resonance spectroscopy of GABA prior to and after repetitive tactile stimulation, we show here that baseline GABA+ levels predict changes in perceptual outcome. Although no net changes in GABA+ are observed, the GABA+ concentration prior to in...
Source: Cerebral Cortex - February 2, 2016 Category: Neurology Authors: Heba, S., Puts, N. A. J., Kalisch, T., Glaubitz, B., Haag, L. M., Lenz, M., Dinse, H. R., Edden, R. A. E., Tegenthoff, M., Schmidt-Wilcke, T. Tags: Original Articles Source Type: research
Evidence for Competition for Target Innervation in the Medial Prefrontal Cortex
Inputs to sensory cortices are known to compete for target innervation through an activity-dependent mechanism during critical periods. To investigate whether this principle also applies to association cortices such as the medial prefrontal cortex (mPFC), we produced a bilateral lesion during early development to the ventral hippocampus (vHC), an input to the mPFC, and analyzed the intensity of the projection from another input, the basolateral amgydala (BLA). We found that axons from the BLA had a higher density of "en passant" boutons in the mPFC of lesioned animals. Furthermore, the density of neurons labeled with retro...
Source: Cerebral Cortex - February 2, 2016 Category: Neurology Authors: Guirado, R., Umemori, J., Sipila, P., Castren, E. Tags: Original Articles Source Type: research
Brain Events Underlying Episodic Memory Changes in Aging: A Longitudinal Investigation of Structural and Functional Connectivity
Episodic memories are established and maintained by close interplay between hippocampus and other cortical regions, but degradation of a fronto-striatal network has been suggested to be a driving force of memory decline in aging. We wanted to directly address how changes in hippocampal-cortical versus striatal-cortical networks over time impact episodic memory with age. We followed 119 healthy participants (20–83 years) for 3.5 years with repeated tests of episodic verbal memory and magnetic resonance imaging for quantification of functional and structural connectivity and regional brain atrophy. While hippocampal-co...
Source: Cerebral Cortex - February 2, 2016 Category: Neurology Authors: Fjell, A. M., Sneve, M. H., Storsve, A. B., Grydeland, H., Yendiki, A., Walhovd, K. B. Tags: Original Articles Source Type: research
Dynamic Expression Patterns of Progenitor and Pyramidal Neuron Layer Markers in the Developing Human Hippocampus
The molecular mechanisms underlying the formation of hippocampus are unknown in humans. To improve our knowledge of molecules that potentially regulate pyramidal neurogenesis and layering in various hippocampal fields, we investigated the expression of progenitor markers and cell fate molecules from gestational week (GW) 9 to GW 20. At GW 9, the progenitor cell compartment of the hippocampal formation mainly consisted of PAX6+ cells in the ventricular zone. Between GW 9 and 11, a second germinal area, the subventricular zone (SVZ), was formed, as shown by TBR2 labeling. Postmitotic markers (TBR1, CTIP2, SATB2, and CUX1) mi...
Source: Cerebral Cortex - February 2, 2016 Category: Neurology Authors: Cipriani, S., Nardelli, J., Verney, C., Delezoide, A.-L., Guimiot, F., Gressens, P., Adle-Biassette, H. Tags: Original Articles Source Type: research
The Attentional Fields of Visual Search in Simultanagnosia and Healthy Individuals: How Object and Space Attention Interact
Simultanagnosia is a deficit in which patients are unable to perceive multiple objects simultaneously. To date, it remains disputed whether this deficit results from disrupted object or space perception. We asked both healthy participants as well as a patient with simultanagnosia to perform different visual search tasks of variable difficulty. We also modulated the number of objects (target and distracters) presented. For healthy participants, we found that each visual search task was performed with a specific "attentional field" depending on the difficulty of visual object processing but not on the number of objects falli...
Source: Cerebral Cortex - February 2, 2016 Category: Neurology Authors: Khan, A. Z., Prost-Lefebvre, M., Salemme, R., Blohm, G., Rossetti, Y., Tilikete, C., Pisella, L. Tags: Original Articles Source Type: research
Temporal Cortex Morphology in Mesial Temporal Lobe Epilepsy Patients and Their Asymptomatic Siblings
Temporal cortex abnormalities are common in patients with mesial temporal lobe epilepsy due to hippocampal sclerosis (MTLE+HS) and believed to be relevant to the underlying mechanisms. In the present study, we set out to determine the familiarity of temporal cortex morphologic alterations in a cohort of MTLE+HS patients and their asymptomatic siblings. A surface-based morphometry (SBM) method was applied to process MRI data acquired from 140 individuals (50 patients with unilateral MTLE+HS, 50 asymptomatic siblings of patients, and 40 healthy controls). Using a region-of-interest approach, alterations in temporal cortex mo...
Source: Cerebral Cortex - February 2, 2016 Category: Neurology Authors: Alhusaini, S., Whelan, C. D., Doherty, C. P., Delanty, N., Fitzsimons, M., Cavalleri, G. L. Tags: Original Articles Source Type: research
Dissociated Neural Representations of Pain Expressions of Different Races
To investigate whether coding pain expressions of own-race and other-race individuals engages overlapping or distinct neuronal populations, we recorded event-related brain potentials from Chinese and Caucasian adults when viewing an adaptor face (with pain or neutral expressions) and a target face (with only pain expression) presented in rapid succession. If distinct neuronal populations are engaged in coding pain expressions of different races, repetition suppression (RS) of neural activity to pain expressions, that is, decreased neural responses to target faces preceded by pain versus neutral adaptors, should occur when ...
Source: Cerebral Cortex - February 2, 2016 Category: Neurology Authors: Sheng, F., Han, X., Han, S. Tags: Original Articles Source Type: research
Pretraining Cortical Thickness Predicts Subsequent Perceptual Learning Rate in a Visual Search Task
We report that preexisting individual differences in the cortical thickness of brain areas involved in a perceptual learning task predict the subsequent perceptual learning rate. Participants trained in a motion-discrimination task involving visual search for a "V"-shaped target motion trajectory among inverted "V"-shaped distractor trajectories. Motion-sensitive area MT+ (V5) was functionally identified as critical to the task: after 3 weeks of training, activity increased in MT+ during task performance, as measured by functional magnetic resonance imaging. We computed the cortical thickness of MT+ from anatomical magneti...
Source: Cerebral Cortex - February 2, 2016 Category: Neurology Authors: Frank, S. M., Reavis, E. A., Greenlee, M. W., Tse, P. U. Tags: Original Articles Source Type: research
Associative Recognition Memory Awareness Improved by Theta-Burst Stimulation of Frontopolar Cortex
Neuroimaging and lesion studies have implicated specific prefrontal cortex locations in subjective memory awareness. Based on this evidence, a rostrocaudal organization has been proposed whereby increasingly anterior prefrontal regions are increasingly involved in memory awareness. We used theta-burst transcranial magnetic stimulation (TBS) to temporarily modulate dorsolateral versus frontopolar prefrontal cortex to test for distinct causal roles in memory awareness. In three sessions, participants received TBS bilaterally to frontopolar cortex, dorsolateral prefrontal cortex, or a control location prior to performing an a...
Source: Cerebral Cortex - February 2, 2016 Category: Neurology Authors: Ryals, A. J., Rogers, L. M., Gross, E. Z., Polnaszek, K. L., Voss, J. L. Tags: Original Articles Source Type: research
Two Types of Neurons in the Primate Globus Pallidus External Segment Play Distinct Roles in Antisaccade Generation
The globus pallidus external segment (GPe) constitutes part of the indirect pathway of the basal ganglia. Because of inhibitory projections from the striatum, most GPe neurons are expected to reduce activity during movements. However, many GPe neurons in fact display increased activity. We previously found that both excitatory and inhibitory responses were modulated during antisaccades, when eyes were directed away from a visual stimulus. To elucidate the roles of these neurons during antisaccades, we examined neuronal activities as monkeys performed antisaccades, prosaccades, and NoGo tasks under 2 conditions. In the Deli...
Source: Cerebral Cortex - February 2, 2016 Category: Neurology Authors: Yoshida, A., Tanaka, M. Tags: Original Articles Source Type: research
