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(Source: Cerebral Cortex)
Source: Cerebral Cortex - November 17, 2016 Category: Neurology Source Type: research
Anisotropy of Human Horizontal and Vertical Navigation in Real Space: Behavioral and PET Correlates
In conclusion, these data indicate a functional anisotropy of human 3D-navigation in favor of the horizontal plane. There are common brain areas for both forms of navigation (hippocampus) as well as unique areas such as the retrosplenial cortex, visual cortex (horizontal navigation), flocculus, and vestibular multisensory cortex (vertical navigation). Visually guided landmark recognition seems to be more important for horizontal navigation, while distance estimation based on vestibular input might be more relevant for vertical navigation. (Source: Cerebral Cortex)
Source: Cerebral Cortex - October 16, 2016 Category: Neurology Authors: Zwergal, A., Schöberl, F., Xiong, G., Pradhan, C., Covic, A., Werner, P., Trapp, C., Bartenstein, P., la Fougere, C., Jahn, K., Dieterich, M., Brandt, T. Tags: Original Articles Source Type: research
Structural Development of Human Fetal and Preterm Brain Cortical Plate Based on Population-Averaged Templates
We hypothesized that the distinct maturational processes take place across different cortical areas from middle fetal stage to normal time of birth and these maturational processes are altered in late third trimester. Fractional anisotropies (FA) from diffusion tensor imaging (DTI) infer the microstructures of the early developing cortical plate. High-resolution DTI of 11 fetal brain specimens at postmenstrual age of 20 weeks (or simplified as 20 weeks), 19 in vivo brains at 35 weeks, and 17 in vivo brains at normal time of birth at term (40 weeks) were acquired. Population-averaged age-specific DTI templates were establis...
Source: Cerebral Cortex - October 16, 2016 Category: Neurology Authors: Yu, Q., Ouyang, A., Chalak, L., Jeon, T., Chia, J., Mishra, V., Sivarajan, M., Jackson, G., Rollins, N., Liu, S., Huang, H. Tags: Original Articles Source Type: research
Unstable Maternal Environment Affects Stress Response in Adult Mice in a Genotype-Dependent Manner
Early postnatal events exert powerful effects on development, inducing persistent functional alterations in different brain network, such as the catecholamine prefrontal–accumbal system, and increasing the risk of developing psychiatric disorders later in life. However, a vast body of literature shows that the interaction between genetic factors and early environmental conditions is crucial for expression of psychopathologies in adulthood. We evaluated the long-lasting effects of a repeated cross-fostering (RCF) procedure in 2 inbred strains of mice (C57BL/6J, DBA/2), known to show a different susceptibility to the d...
Source: Cerebral Cortex - October 16, 2016 Category: Neurology Authors: Di Segni, M., Andolina, D., Luchetti, A., Babicola, L., D'Apolito, L. I., Pascucci, T., Conversi, D., Accoto, A., D'Amato, F. R., Ventura, R. Tags: Original Articles Source Type: research
Multiple Causal Links Between Magnocellular-Dorsal Pathway Deficit and Developmental Dyslexia
Although impaired auditory–phonological processing is the most popular explanation of developmental dyslexia (DD), the literature shows that the combination of several causes rather than a single factor contributes to DD. Functioning of the visual magnocellular–dorsal (MD) pathway, which plays a key role in motion perception, is a much debated, but heavily suspected factor contributing to DD. Here, we employ a comprehensive approach that incorporates all the accepted methods required to test the relationship between the MD pathway dysfunction and DD. The results of 4 experiments show that (1) Motion perception ...
Source: Cerebral Cortex - October 16, 2016 Category: Neurology Authors: Gori, S., Seitz, A. R., Ronconi, L., Franceschini, S., Facoetti, A. Tags: Original Articles Source Type: research
Mirror Motor Activity During Right-Hand Contractions and Its Relation to White Matter in the Posterior Midbody of the Corpus Callosum
Cortical activity during simple unimanual actions is typically lateralized to contralateral sensorimotor areas, while a more bilateral pattern is observed with an increase in task demands. In parallel, increasing task demands are associated with subtle mirror muscle activity in the resting hand, implying a relative loss in motor selectivity. The corpus callosum (CC) is crucially involved in unimanual tasks by mediating both facilitatory and inhibitory interactions between bilateral motor cortical systems, but its association with mirror motor activity is yet unknown. Here, we used diffusion-weighted imaging and bilateral e...
Source: Cerebral Cortex - October 16, 2016 Category: Neurology Authors: Sehm, B., Steele, C. J., Villringer, A., Ragert, P. Tags: Original Articles Source Type: research
Desynchronization and Plasticity of Striato-frontal Connectivity in Major Depressive Disorder
Major depressive disorder (MDD) is associated with dysfunctional corticolimbic networks, making functional connectivity studies integral for understanding the mechanisms underlying MDD pathophysiology and treatment. Resting-state functional connectivity (RSFC) studies analyze patterns of temporally coherent intrinsic brain activity in "resting-state networks" (RSNs). The default-mode network (DMN) has been of particular interest to depression research; however, a single RSN is unlikely to capture MDD pathophysiology in its entirety, and the DMN itself can be characterized by multiple RSNs. This, coupled with conflicting pr...
Source: Cerebral Cortex - October 16, 2016 Category: Neurology Authors: Leaver, A. M., Espinoza, R., Joshi, S. H., Vasavada, M., Njau, S., Woods, R. P., Narr, K. L. Tags: Original Articles Source Type: research
The Neural Mechanisms of Prediction in Visual Search
The speed of visual search depends on bottom-up stimulus features (e.g., we quickly locate a red item among blue distractors), but it is also facilitated by the presence of top-down perceptual predictions about the item. Here, we identify the nature, source, and neuronal substrate of the predictions that speed up resumed visual search. Human subjects were presented with a visual search array that was repeated up to 4 times, while brain activity was recorded using magnetoencephalography (MEG). Behaviorally, we observed a bimodal reaction time distribution for resumed visual search, indicating that subjects were extraordinar...
Source: Cerebral Cortex - October 16, 2016 Category: Neurology Authors: Spaak, E., Fonken, Y., Jensen, O., de Lange, F. P. Tags: Original Articles Source Type: research
Altered Prefrontal Excitation/Inhibition Balance and Prefrontal Output: Markers of Aging in Human Memory Networks
Memory impairments and heightened prefrontal cortical (PFC) activity are hallmarks of cognitive and neurobiological human aging. While structural integrity of PFC gray matter and interregional white matter tracts are thought to impact memory processing, the balance of neurotransmitters within the PFC itself is less well understood. We used fMRI to establish whole-brain networks involved in a memory encoding task and dynamic causal models (DCMs) for fMRI to determine the causal relationships between these areas. These data revealed enhanced connectivity from PFC to medial temporal cortex that negatively correlated with reca...
Source: Cerebral Cortex - October 16, 2016 Category: Neurology Authors: Legon, W., Punzell, S., Dowlati, E., Adams, S. E., Stiles, A. B., Moran, R. J. Tags: Original Articles Source Type: research
Functional Reduction in Cannabinoid-Sensitive Heterotypic Inhibition of Dentate Basket Cells in Epilepsy: Impact on Network Rhythms
Strong perisomatic inhibition by fast-spiking basket cells (FS-BCs) regulates dentate throughput. Homotypic FS-BC interconnections that support gamma oscillations, and heterotypic inputs from diverse groups of interneurons that receive extensive neurochemical regulation, together, shape FS-BC activity patterns. However, whether seizures precipitate functional changes in inhibitory networks and contribute to abnormal network activity in epilepsy is not known. In the first recordings from dentate interneuronal pairs in a model of temporal lobe epilepsy, we demonstrate that status epilepticus (SE) selectively compromises GABA...
Source: Cerebral Cortex - October 16, 2016 Category: Neurology Authors: Yu, J., Proddutur, A., Swietek, B., Elgammal, F. S., Santhakumar, V. Tags: Original Articles Source Type: research
Reelin Regulates the Maturation of Dendritic Spines, Synaptogenesis and Glial Ensheathment of Newborn Granule Cells
The Reelin pathway is essential for both neural migration and for the development and maturation of synaptic connections. However, its role in adult synaptic formation and remodeling is still being investigated. Here, we investigated the impact of the Reelin/Dab1 pathway on the synaptogenesis of newborn granule cells (GCs) in the young-adult mouse hippocampus. We show that neither Reelin overexpression nor the inactivation of its intracellular adapter, Dab1, substantially alters dendritic spine numbers in these neurons. In contrast, 3D-electron microscopy (focused ion beam milling/scanning electron microscope) reveale...
Source: Cerebral Cortex - October 16, 2016 Category: Neurology Authors: Bosch, C., Masachs, N., Exposito-Alonso, D., Martinez, A., Teixeira, C. M., Fernaud, I., Pujadas, L., Ulloa, F., Comella, J. X., DeFelipe, J., Merchan-Perez, A., Soriano, E. Tags: Original Articles Source Type: research
From Shortage to Surge: A Developmental Switch in Hippocampal-Prefrontal Coupling in a Gene-Environment Model of Neuropsychiatric Disorders
Cognitive deficits represent a major burden of neuropsychiatric disorders and result in part from abnormal communication within hippocampal–prefrontal circuits. While it has been hypothesized that this network dysfunction arises during development, long before the first clinical symptoms, experimental evidence is still missing. Here, we show that pre-juvenile mice mimicking genetic and environmental risk factors of disease (dual-hit GE mice) have poorer recognition memory that correlates with augmented coupling by synchrony and stronger directed interactions between prefrontal cortex and hippocampus. The network dysf...
Source: Cerebral Cortex - October 16, 2016 Category: Neurology Authors: Hartung, H., Cichon, N., De Feo, V., Riemann, S., Schildt, S., Lindemann, C., Mulert, C., Gogos, J. A., Hanganu-Opatz, I. L. Tags: Original Articles Source Type: research
L-DOPA Oppositely Regulates Synaptic Strength and Spine Morphology in D1 and D2 Striatal Projection Neurons in Dyskinesia
Dopamine depletion in Parkinson's disease (PD) produces dendritic spine loss in striatal medium spiny neurons (MSNs) and increases their excitability. However, the synaptic changes that occur in MSNs in PD, in particular those induced by chronic L-3,4-dihydroxyphenylalanine (L-DOPA) treatment, are still poorly understood. We exposed BAC-transgenic D1-tomato and D2-eGFP mice to PD and dyskinesia model paradigms, enabling cell type-specific assessment of changes in synaptic physiology and morphology. The distinct fluorescence markers allowed us to identify D1 and D2 MSNs for analysis using intracellular sharp electrode recor...
Source: Cerebral Cortex - October 16, 2016 Category: Neurology Authors: Suarez, L. M., Solis, O., Aguado, C., Lujan, R., Moratalla, R. Tags: Original Articles Source Type: research
Distinct Spatiotemporal Response Properties of Excitatory Versus Inhibitory Neurons in the Mouse Auditory Cortex
In the auditory system, early neural stations such as brain stem are characterized by strict tonotopy, which is used to deconstruct sounds to their basic frequencies. But higher along the auditory hierarchy, as early as primary auditory cortex (A1), tonotopy starts breaking down at local circuits. Here, we studied the response properties of both excitatory and inhibitory neurons in the auditory cortex of anesthetized mice. We used in vivo two photon-targeted cell-attached recordings from identified parvalbumin-positive neurons (PVNs) and their excitatory pyramidal neighbors (PyrNs). We show that PyrNs are locally heterogen...
Source: Cerebral Cortex - October 16, 2016 Category: Neurology Authors: Maor, I., Shalev, A., Mizrahi, A. Tags: Original Articles Source Type: research
Mapping the Multiple Graded Contributions of the Anterior Temporal Lobe Representational Hub to Abstract and Social Concepts: Evidence from Distortion-corrected fMRI
A growing body of recent convergent evidence indicates that the anterior temporal lobe (ATL) has connectivity-derived graded differences in semantic function: the ventrolateral region appears to be the transmodal, omni-category center-point of the hub whilst secondary contributions come from the peripheries of the hub in a manner that reflects their differential connectivity to different input/output modalities. One of the key challenges for this neurocognitive theory is how different types of concept, especially those with less reliance upon external sensory experience (such as abstract and social concepts), are coded acr...
Source: Cerebral Cortex - October 16, 2016 Category: Neurology Authors: Binney, R. J., Hoffman, P., Lambon Ralph, M. A. Tags: Original Articles Source Type: research
