Blocking miRNA Biogenesis in Adult Forebrain Neurons Enhances Seizure Susceptibility, Fear Memory, and Food Intake by Increasing Neuronal Responsiveness
The RNase Dicer is essential for the maturation of most microRNAs, a molecular system that plays an essential role in fine-tuning gene expression. To gain molecular insight into the role of Dicer and the microRNA system in brain function, we conducted 2 complementary RNA-seq screens in the hippocampus of inducible forebrain-restricted Dicer1 mutants aimed at identifying the microRNAs primarily affected by Dicer loss and their targets, respectively. Functional genomics analyses predicted the main biological processes and phenotypes associated with impaired microRNA maturation, including categories related to microRNA biolog...
Source: Cerebral Cortex - March 10, 2016 Category: Neurology Authors: Fiorenza, A., Lopez-Atalaya, J. P., Rovira, V., Scandaglia, M., Geijo-Barrientos, E., Barco, A. Tags: Original Articles Source Type: research
The Representation of Object-Directed Action and Function Knowledge in the Human Brain
The appropriate use of everyday objects requires the integration of action and function knowledge. Previous research suggests that action knowledge is represented in frontoparietal areas while function knowledge is represented in temporal lobe regions. Here we used multivoxel pattern analysis to investigate the representation of object-directed action and function knowledge while participants executed pantomimes of familiar tool actions. A novel approach for decoding object knowledge was used in which classifiers were trained on one pair of objects and then tested on a distinct pair; this permitted a measurement of classif...
Source: Cerebral Cortex - March 10, 2016 Category: Neurology Authors: Chen, Q., Garcea, F. E., Mahon, B. Z. Tags: Original Articles Source Type: research
Superficial Layer-Specific Histaminergic Modulation of Medial Entorhinal Cortex Required for Spatial Learning
The medial entorhinal cortex (MEC) plays a crucial role in spatial learning and memory. Whereas the MEC receives a dense histaminergic innervation from the tuberomamillary nucleus of the hypothalamus, the functions of histamine in this brain region remain unclear. Here, we show that histamine acts via H1Rs to directly depolarize the principal neurons in the superficial, but not deep, layers of the MEC when recording at somata. Moreover, histamine decreases the spontaneous GABA, but not glutamate, release onto principal neurons in the superficial layers by acting at presynaptic H3Rs without effect on synaptic release in the...
Source: Cerebral Cortex - March 10, 2016 Category: Neurology Authors: He, C., Luo, F., Chen, X., Chen, F., Li, C., Ren, S., Qiao, Q., Zhang, J., de Lecea, L., Gao, D., Hu, Z. Tags: Original Articles Source Type: research
Cytoarchitecture-Dependent Decrease in Propagation Velocity of Cortical Spreading Depression in the Rat Insular Cortex Revealed by Optical Imaging
Cortical spreading depression (SD) is a self-propagating wave of depolarization accompanied by a substantial disturbance of the ionic distribution between the intra- and extracellular compartments. Glial cells, including astrocytes, play critical roles in maintenance of the extracellular environment, including ionic distribution. Therefore, SD propagation in the cerebral cortex may depend on the density of astrocytes. The present study aimed to examine the profile of SD propagation in the insular cortex (IC), which is located between the neocortex and paleocortex and is where the density of astrocytes gradually changes. Th...
Source: Cerebral Cortex - March 10, 2016 Category: Neurology Authors: Fujita, S., Mizoguchi, N., Aoki, R., Cui, Y., Koshikawa, N., Kobayashi, M. Tags: Original Articles Source Type: research
Dendritic Target Region-Specific Formation of Synapses Between Excitatory Layer 4 Neurons and Layer 6 Pyramidal Cells
Excitatory connections between neocortical layer 4 (L4) and L6 are part of the corticothalamic feedback microcircuitry. Here we studied the intracortical element of this feedback loop, the L4 spiny neuron-to-L6 pyramidal cell connection. We found that the distribution of synapses onto both putative corticothalamic (CT) and corticocortical (CC) L6 pyramidal cells (PCs) depends on the presynaptic L4 neuron type but is independent of the postsynaptic L6 PC type. L4 spiny stellate cells establish synapses on distal apical tuft dendrites of L6 PCs and elicit slow unitary excitatory postsynaptic potentials (uEPSPs) in L6 somata....
Source: Cerebral Cortex - March 10, 2016 Category: Neurology Authors: Qi, G., Feldmeyer, D. Tags: Original Articles Source Type: research
Functional Imaging of the Developing Brain at the Bedside Using Diffuse Optical Tomography
While histological studies and conventional magnetic resonance imaging (MRI) investigations have elucidated the trajectory of structural changes in the developing brain, less is known regarding early functional cerebral development. Recent investigations have demonstrated that resting-state functional connectivity MRI (fcMRI) can identify networks of functional cerebral connections in infants. However, technical and logistical challenges frequently limit the ability to perform MRI scans early or repeatedly in neonates, particularly in those at greatest risk for adverse neurodevelopmental outcomes. High-density diffuse opti...
Source: Cerebral Cortex - March 10, 2016 Category: Neurology Authors: Ferradal, S. L., Liao, S. M., Eggebrecht, A. T., Shimony, J. S., Inder, T. E., Culver, J. P., Smyser, C. D. Tags: Original Articles Source Type: research
Dopaminergic Modulation of Cognitive Preparation for Overt Reading: Evidence from the Study of Genetic Polymorphisms
Choosing and implementing the rules for contextually adequate behavior depends on frontostriatal interactions. Observations in Parkinson's disease and pharmacological manipulations of dopamine transmission suggest that these corticobasal loops are modulated by dopamine. To determine, therefore, the physiological contributions of dopamine to task-rule–related processing, we performed a cue–target fMRI reading paradigm in 71 healthy participants and investigated the effects of COMT Val158Met, DAT1 VNTR 9/10, and DRD2/ANKK1 polymorphisms. The DRD2/ANKK1 polymorphism did not affect results. Intermediate prefrontal ...
Source: Cerebral Cortex - March 10, 2016 Category: Neurology Authors: Arnold, C., Gispert, S., Bonig, H., von Wegner, F., Somasundaram, S., Kell, C. A. Tags: Original Articles Source Type: research
Prefrontal Cortical Inactivations Decrease Willingness to Expend Cognitive Effort on a Rodent Cost/Benefit Decision-Making Task
Personal success often necessitates expending greater effort for greater reward but, equally important, also requires judicious use of our limited cognitive resources (e.g., attention). Previous animal models have shown that the prelimbic (PL) and infralimbic (IL) regions of the prefrontal cortex (PFC) are not involved in (physical) effort-based choice, whereas human studies have demonstrated PFC contributions to (mental) effort. Here, we utilize the rat Cognitive Effort Task (rCET) to probe PFC's role in effort-based decision making. In the rCET, animals can choose either an easy trial, where the attentional demand is low...
Source: Cerebral Cortex - March 10, 2016 Category: Neurology Authors: Hosking, J. G., Cocker, P. J., Winstanley, C. A. Tags: Original Articles Source Type: research
Altered Functionality, Morphology, and Vesicular Glutamate Transporter Expression of Cortical Motor Neurons from a Presymptomatic Mouse Model of Amyotrophic Lateral Sclerosis
Amyotrophic lateral sclerosis (ALS) is a lethal disorder characterized by the gradual degeneration of motor neurons in the cerebrospinal axis. Whether upper motor neuron hyperexcitability, which is a feature of ALS, provokes dysfunction of glutamate metabolism and degeneration of lower motor neurons via an anterograde process is undetermined. To examine whether early changes in upper motor neuron activity occur in association with glutamatergic alterations, we performed whole-cell patch-clamp recordings to analyze excitatory properties of Layer V cortical motor neurons and excitatory postsynaptic currents (EPSCs) in presym...
Source: Cerebral Cortex - March 10, 2016 Category: Neurology Authors: Saba, L., Viscomi, M. T., Caioli, S., Pignataro, A., Bisicchia, E., Pieri, M., Molinari, M., Ammassari-Teule, M., Zona, C. Tags: Original Articles Source Type: research
Topologically Reorganized Connectivity Architecture of Default-Mode, Executive-Control, and Salience Networks across Working Memory Task Loads
The human brain is topologically organized into a set of spatially distributed, functionally specific networks. Of these networks, the default-mode network (DMN), executive-control network (ECN), and salience network (SN) have received the most attention recently for their vital roles in cognitive functions. However, very little is known about whether and how the interactions within and between these 3 networks would be modulated by cognitive demands. Here, we employed graph-based modularity analysis to identify the DMN, ECN, and SN during an N-back working memory (WM) task and further investigated the modulation of intra-...
Source: Cerebral Cortex - March 10, 2016 Category: Neurology Authors: Liang, X., Zou, Q., He, Y., Yang, Y. Tags: Original Articles Source Type: research
REM Sleep-Dependent Bidirectional Regulation of Hippocampal-Based Emotional Memory and LTP
Prolonged rapid-eye-movement (REM) sleep deprivation has long been used to study the role of REM sleep in learning and memory processes. However, this method potentially induces stress and fatigue that may directly affect cognitive functions. Here, by using a short-term and nonstressful REM sleep deprivation (RSD) method we assessed in rats the bidirectional influence of reduced and increased REM sleep amount on hippocampal-dependent emotional memory and plasticity. Our results indicate that 4 h RSD impaired consolidation of contextual fear conditioning (CFC) and induction of long-term potentiation (LTP), while decreasing ...
Source: Cerebral Cortex - March 10, 2016 Category: Neurology Authors: Ravassard, P., Hamieh, A. M., Joseph, M. A., Fraize, N., Libourel, P.-A., Lebarillier, L., Arthaud, S., Meissirel, C., Touret, M., Malleret, G., Salin, P.-A. Tags: Original Articles Source Type: research
Voice Recognition in Face-Blind Patients
Right or bilateral anterior temporal damage can impair face recognition, but whether this is an associative variant of prosopagnosia or part of a multimodal disorder of person recognition is an unsettled question, with implications for cognitive and neuroanatomic models of person recognition. We assessed voice perception and short-term recognition of recently heard voices in 10 subjects with impaired face recognition acquired after cerebral lesions. All 4 subjects with apperceptive prosopagnosia due to lesions limited to fusiform cortex had intact voice discrimination and recognition. One subject with bilateral fusiform an...
Source: Cerebral Cortex - March 10, 2016 Category: Neurology Authors: Liu, R. R., Pancaroglu, R., Hills, C. S., Duchaine, B., Barton, J. J. S. Tags: Original Articles Source Type: research
Synaptic Targeting of Kainate Receptors
When native and recombinant kainate receptors (KARs) are compared, there is a mismatch in several of their functional properties. While both generate currents, synaptic responses mediated by KARs have rarely observed in cultured hippocampal neurons. The recent discovery of auxiliary proteins for KARs, such as Netos, offers an explanation for these discrepancies. We found that the GluK5 KAR subunit and the ancillary proteins, Neto1 and Neto2, are not expressed by hippocampal neurons in culture. Therefore, we used this model to directly test whether these proteins are required for the synaptic localization of KARs. Transfect...
Source: Cerebral Cortex - March 10, 2016 Category: Neurology Authors: Palacios-Filardo, J., Aller, M. I., Lerma, J. Tags: Original Articles Source Type: research
Developmental Sculpting of Intracortical Circuits by MHC Class I H2-Db and H2-Kb
Synapse pruning is an activity-regulated process needed for proper circuit sculpting in the developing brain. Major histocompatibility class I (MHCI) molecules are regulated by activity, but little is known about their role in the development of connectivity in cortex. Here we show that protein for 2 MHCI molecules H2-Kb and H2-Db is associated with synapses in the visual cortex. Pyramidal neurons in mice lacking H2-Kb and H2-Db (KbDb KO) have more extensive cortical connectivity than normal. Modified rabies virus tracing was used to monitor the extent of pyramidal cell connectivity: Horizontal connectivity is greater in t...
Source: Cerebral Cortex - March 10, 2016 Category: Neurology Authors: Adelson, J. D., Sapp, R. W., Brott, B. K., Lee, H., Miyamichi, K., Luo, L., Cheng, S., Djurisic, M., Shatz, C. J. Tags: Original Articles Source Type: research
Anatomical Abnormalities in Autism?
Substantial controversy exists regarding the presence and significance of anatomical abnormalities in autism spectrum disorders (ASD). The release of the Autism Brain Imaging Data Exchange (~1000 participants, age 6–65 years) offers an unprecedented opportunity to conduct large-scale comparisons of anatomical MRI scans across groups and to resolve many of the outstanding questions. Comprehensive univariate analyses using volumetric, thickness, and surface area measures of over 180 anatomically defined brain areas, revealed significantly larger ventricular volumes, smaller corpus callosum volume (central segment only)...
Source: Cerebral Cortex - March 10, 2016 Category: Neurology Authors: Haar, S., Berman, S., Behrmann, M., Dinstein, I. Tags: Original Articles Source Type: research
