Identification of Parvalbumin Interneurons as Cellular Substrate of Fear Memory Persistence
Parvalbumin-positive (PV) basket cells provide perisomatic inhibition in the cortex and hippocampus and control generation of memory-related network activity patterns, such as sharp wave ripples (SPW-R). Deterioration of this class of fast-spiking interneurons has been observed in neuropsychiatric disorders and evidence from animal models suggests their involvement in the acquisition and extinction of fear memories. Here, we used mice with neuron type-targeted expression of the presynaptic gain-of-function glycine receptor RNA variant GlyR α3L185L to genetically enhance the network activity of PV interneurons. These ...
Source: Cerebral Cortex - April 12, 2016 Category: Neurology Authors: Calıskan, G., Müller, I., Semtner, M., Winkelmann, A., Raza, A. S., Hollnagel, J. O., Rösler, A., Heinemann, U., Stork, O., Meier, J. C. Tags: Articles Source Type: research
Bidirectional Modulation of Numerical Magnitude
Numerical cognition is critical for modern life; however, the precise neural mechanisms underpinning numerical magnitude allocation in humans remain obscure. Based upon previous reports demonstrating the close behavioral and neuro-anatomical relationship between number allocation and spatial attention, we hypothesized that these systems would be subject to similar control mechanisms, namely dynamic interhemispheric competition. We employed a physiological paradigm, combining visual and vestibular stimulation, to induce interhemispheric conflict and subsequent unihemispheric inhibition, as confirmed by transcranial direct c...
Source: Cerebral Cortex - April 12, 2016 Category: Neurology Authors: Arshad, Q., Nigmatullina, Y., Nigmatullin, R., Asavarut, P., Goga, U., Khan, S., Sander, K., Siddiqui, S., Roberts, R. E., Cohen Kadosh, R., Bronstein, A. M., Malhotra, P. A. Tags: Articles Source Type: research
YAP Is a Critical Inducer of SOCS3, Preventing Reactive Astrogliosis
Yes-associated protein (YAP) is a key transcriptional cofactor of the Hippo pathway, critical for the development of multiple organs. However, its role in the developing brain remains poorly understood. Here, we found that YAP was highly expressed in astrocytes and YAP deletion elevated the astrocytic activation in culture and in vivo, which was associated with microglial activation. At the molecular level, YAP in astrocytes was activated by IFNβ or ciliary neurotrophic factor (CNTF), which was necessary for IFNβ or CNTF induction of the suppressor of cytokine signaling 3 (SOCS3), a negative regulator of the Janu...
Source: Cerebral Cortex - April 12, 2016 Category: Neurology Authors: Huang, Z., Wang, Y., Hu, G., Zhou, J., Mei, L., Xiong, W.-C. Tags: Articles Source Type: research
Exploring the Early Organization and Maturation of Linguistic Pathways in the Human Infant Brain
Linguistic processing is based on a close collaboration between temporal and frontal regions connected by two pathways: the "dorsal" and "ventral pathways" (assumed to support phonological and semantic processing, respectively, in adults). We investigated here the development of these pathways at the onset of language acquisition, during the first post-natal weeks, using cross-sectional diffusion imaging in 21 healthy infants (6–22 weeks of age) and 17 young adults. We compared the bundle organization and microstructure at these two ages using tractography and original clustering analyses of diffusion tensor imaging ...
Source: Cerebral Cortex - April 12, 2016 Category: Neurology Authors: Dubois, J., Poupon, C., Thirion, B., Simonnet, H., Kulikova, S., Leroy, F., Hertz-Pannier, L., Dehaene-Lambertz, G. Tags: Articles Source Type: research
Conjunctive Coding of Complex Object Features
Critical to perceiving an object is the ability to bind its constituent features into a cohesive representation, yet the manner by which the visual system integrates object features to yield a unified percept remains unknown. Here, we present a novel application of multivoxel pattern analysis of neuroimaging data that allows a direct investigation of whether neural representations integrate object features into a whole that is different from the sum of its parts. We found that patterns of activity throughout the ventral visual stream (VVS), extending anteriorly into the perirhinal cortex (PRC), discriminated between the sa...
Source: Cerebral Cortex - April 12, 2016 Category: Neurology Authors: Erez, J., Cusack, R., Kendall, W., Barense, M. D. Tags: Articles Source Type: research
Cortical Divergent Projections in Mice Originate from Two Sequentially Generated, Distinct Populations of Excitatory Cortical Neurons with Different Initial Axonal Outgrowth Characteristics
Excitatory cortical neurons project to various subcortical and intracortical regions, and exhibit diversity in their axonal connections. Although this diversity may develop from primary axons, how many types of axons initially occur remains unknown. Using a sparse-labeling in utero electroporation method, we investigated the axonal outgrowth of these neurons in mice and correlated the data with axonal projections in adults. Examination of lateral cortex neurons labeled during the main period of cortical neurogenesis (E11.5–E15.5) indicated that axonal outgrowth commonly occurs in the intermediate zone. Conversely, th...
Source: Cerebral Cortex - April 12, 2016 Category: Neurology Authors: Hatanaka, Y., Namikawa, T., Yamauchi, K., Kawaguchi, Y. Tags: Articles Source Type: research
Extended Production of Cortical Interneurons into the Third Trimester of Human Gestation
In humans, the developmental origins of interneurons in the third trimester of pregnancy and the timing of completion of interneuron neurogenesis have remained unknown. Here, we show that the total and cycling Nkx2.1+ and Dlx2+ interneuron progenitors as well as Sox2+ precursor cells were higher in density in the medial ganglionic eminence (MGE) compared with the lateral ganglionic eminence and cortical ventricular/subventricular zone (VZ/SVZ) of 16–35 gw subjects. The proliferation of these progenitors reduced as a function of gestational age, almost terminating by 35 gw. Proliferating Dlx2+ cells were higher in den...
Source: Cerebral Cortex - April 12, 2016 Category: Neurology Authors: Arshad, A., Vose, L. R., Vinukonda, G., Hu, F., Yoshikawa, K., Csiszar, A., Brumberg, J. C., Ballabh, P. Tags: Articles Source Type: research
Co-Activation-Based Parcellation of the Lateral Prefrontal Cortex Delineates the Inferior Frontal Junction Area
The inferior frontal junction (IFJ) area, a small region in the posterior lateral prefrontal cortex (LPFC), has received increasing interest in recent years due to its central involvement in the control of action, attention, and memory. Yet, both its function and anatomy remain controversial. Here, we employed a meta-analytic parcellation of the left LPFC to show that the IFJ can be isolated based on its specific functional connections. A seed region, oriented along the left inferior frontal sulcus (IFS), was subdivided via cluster analyses of voxel-wise whole-brain co-activation patterns. The ensuing clusters were charact...
Source: Cerebral Cortex - April 12, 2016 Category: Neurology Authors: Muhle-Karbe, P. S., Derrfuss, J., Lynn, M. T., Neubert, F. X., Fox, P. T., Brass, M., Eickhoff, S. B. Tags: Articles Source Type: research
The Dual-Loop Model and the Human Mirror Neuron System: an Exploratory Combined fMRI and DTI Study of the Inferior Frontal Gyrus
The inferior frontal gyrus (IFG) is active during both goal-directed action and while observing the same motor act, leading to the idea that also the meaning of a motor act (action understanding) is represented in this "mirror neuron system" (MNS). However, in the dual-loop model, based on dorsal and ventral visual streams, the MNS is thought to be a function of the dorsal steam, projecting to pars opercularis (BA44) of IFG, while recent studies suggest that conceptual meaning and semantic analysis are a function of ventral connections, projecting mainly to pars triangularis (BA45) of IFG. To resolve this discrepancy, we i...
Source: Cerebral Cortex - April 12, 2016 Category: Neurology Authors: Hamzei, F., Vry, M.-S., Saur, D., Glauche, V., Hoeren, M., Mader, I., Weiller, C., Rijntjes, M. Tags: Articles Source Type: research
A Major Human White Matter Pathway Between Dorsal and Ventral Visual Cortex
Human visual cortex comprises many visual field maps organized into clusters. A standard organization separates visual maps into 2 distinct clusters within ventral and dorsal cortex. We combined fMRI, diffusion MRI, and fiber tractography to identify a major white matter pathway, the vertical occipital fasciculus (VOF), connecting maps within the dorsal and ventral visual cortex. We use a model-based method to assess the statistical evidence supporting several aspects of the VOF wiring pattern. There is strong evidence supporting the hypothesis that dorsal and ventral visual maps communicate through the VOF. The cortical p...
Source: Cerebral Cortex - April 12, 2016 Category: Neurology Authors: Takemura, H., Rokem, A., Winawer, J., Yeatman, J. D., Wandell, B. A., Pestilli, F. Tags: Articles Source Type: research
GABA-Synthesizing Enzymes in Calbindin and Calretinin Neurons in Monkey Prefrontal Cortex
Non-overlapping groups of cortical -aminobutyric acid-releasing (GABAergic) neurons are identifiable by the presence of calbindin (CB), calretinin (CR), or parvalbumin (PV). Boutons from PV neuron subtypes are also distinguishable by differences in protein levels of the GABA-synthesizing enzymes GAD65 and GAD67. Multilabel fluorescence microscopy was used to determine if this diversity extends to boutons of CB and CR neurons in monkey prefrontal cortex. CB and CR neurons gave rise to 3 subpopulations of GAD-containing boutons: GAD65+, GAD67+, and GAD65/GAD67+. Somatostatin and vasoactive intestinal peptide-expressing neuro...
Source: Cerebral Cortex - April 12, 2016 Category: Neurology Authors: Rocco, B. R., Sweet, R. A., Lewis, D. A., Fish, K. N. Tags: Articles Source Type: research
Fronto-Parietal Network Reconfiguration Supports the Development of Reasoning Ability
The goal of this fMRI study was to examine how well developmental improvements in reasoning ability can be explained by changes in functional connectivity between specific nodes in prefrontal and parietal cortices. To this end, we examined connectivity within the lateral fronto-parietal network (LFPN) and its relation to reasoning ability in 132 children and adolescents aged 6–18 years, 56 of whom were scanned twice over the course of 1.5 years. Developmental changes in strength of connections within the LFPN were most prominent in late childhood and early adolescence. Reasoning ability was related to functional conn...
Source: Cerebral Cortex - April 12, 2016 Category: Neurology Authors: Wendelken, C., Ferrer, E., Whitaker, K. J., Bunge, S. A. Tags: Articles Source Type: research
Impaired Organization of Paired-Pulse TMS-Induced I-Waves After Human Spinal Cord Injury
Paired-pulse transcranial magnetic stimulation (TMS) of the human motor cortex results in consecutive facilitatory motor-evoked potential (MEP) peaks in surface electromyography in intact humans. Here, we tested the effect of an incomplete cervical spinal cord injury (SCI) on early (first) and late (second and third) MEP peaks in a resting intrinsic finger muscle. We found that all peaks had decreased amplitude in SCI subjects compared with controls. The second and third peaks were delayed with the third peak also showing an increased duration. The delay of the third peak was smaller than that seen in controls at lower sti...
Source: Cerebral Cortex - April 12, 2016 Category: Neurology Authors: Cirillo, J., Calabro, F. J., Perez, M. A. Tags: Articles Source Type: research
Region-Specific Summation Patterns Inform the Role of Cortical Areas in Selecting Motor Plans
Given an instruction regarding which effector to move and what location to move to, simply adding the effector and spatial signals together will not lead to movement selection. For this, a nonlinearity is required. Thresholds, for example, can be used to select a particular response and reject others. Here we consider another useful nonlinearity, a supralinear multiplicative interaction. To help select a motor plan, spatial and effector signals could multiply and thereby amplify each other. Such an amplification could constitute one step within a distributed network involved in response selection, effectively boosting one ...
Source: Cerebral Cortex - April 12, 2016 Category: Neurology Authors: Chang, S. W. C., Calton, J. L., Lawrence, B. M., Dickinson, A. R., Snyder, L. H. Tags: Articles Source Type: research
Causal Interactions Within a Frontal-Cingulate-Parietal Network During Cognitive Control: Convergent Evidence from a Multisite-Multitask Investigation
Cognitive control plays an important role in goal-directed behavior, but dynamic brain mechanisms underlying it are poorly understood. Here, using multisite fMRI data from over 100 participants, we investigate causal interactions in three cognitive control tasks within a core Frontal-Cingulate-Parietal network. We found significant causal influences from anterior insula (AI) to dorsal anterior cingulate cortex (dACC) in all three tasks. The AI exhibited greater net causal outflow than any other node in the network. Importantly, a similar pattern of causal interactions was uncovered by two different computational methods fo...
Source: Cerebral Cortex - April 12, 2016 Category: Neurology Authors: Cai, W., Chen, T., Ryali, S., Kochalka, J., Li, C.-S. R., Menon, V. Tags: Articles Source Type: research
