What is neurorepresentationalism?:From neural activity and predictive processing to multi-level representations and consciousness

This review provides an update on Neurorepresentationalism, a theoretical framework that defines conscious experience as multimodal, situational survey and explains its neural basis from brain systems constructing best-guess representations of sensations originating in our environment and body (Pennartz, 2015)

Gene expression analysis of neuronal precursors from adult mouse brain and differential screen for neural stem cell markers

In the adult mouse brain, neuronal precursor cells continuously emanate from neural stem cells (NSC) in the subventricular zone (SVZ) and migrate into the olfactory bulb (OB) where they differentiate to serve as replenishment for GABAergic interneurons. During the migration process, PSA-NCAM (Polysialic acid-Neural cell adhesion molecule) specifically marks the neuronal precursors (PSA+ cells). This phenomenon was exploited in the framework of this doctoral thesis to isolate a homogeneous cell population of neuronal precursor cells using Fluorescence-activated cell sorting. Here, the first comprehensive picture of the gene expression in PSA+ precursors was generated using Serial Analysis of Gene Expression (SAGE). Comparison of SAGE data for PSA+ cells and for adult total brain (ATB) led to the identification of precursor-enriched genes. For selected genes, the results were validated using cDNA microarrays and quantitative real-time PCR, and the expression was analyzed at the cellular level in mouse brain using in situ hybridizations. Genes previously described in this context like the proliferation inhibitor CD24, the sialyltransferase STX and the Reelin receptor ApoER2 confirmed the identity of the precursor cells and the accuracy of the SAGE. Individual characterized genes that were so far unknown in the PSA+ cell population were identified as well as functional groups of genes by means of cluster analysis of SAGE data. The presence of transcription factors of the Sox and Dlx families, Pax6 and Meis2 indicated that secondary neurogenesis might be largely controlled by the same factors that are active during development. Clusters for apoptosis and proliferation are both upregulated. The high expression of chemotactic factors in the neuronal precursors suggests that they might be involved in neuronal cell migration. In addition, novel genes like RIKEN 3110003A17 were observed. First functional data based on the SAGE are being generated in the framework of our collaboration with the Developmental Biology Institute of Marseille. Given that a lack of markers for NSC considerably impedes progress in NSC biology, the second part of this work aimed at identifying potential NSC markers by comparing SAGE data for embryonic stem (ES) cells, PSA+ cells and ATB. The selection strategy was based on two assumptions. First, in a hierarchical order of developmental potential, ES cells are positioned above NSC, which are above restricted precursors that in turn are above adult neurons and glia. Second, the genetic programs of ES cells and NSC overlap. Thus, genes that are highly expressed in ES cells and downregulated or absent in PSA+ neuronal precursors and ATB should in part also be expressed by the few stem cells in the adult brain. Eight candidates coding for cell surface proteins were identified from the resulting list of candidates and were investigated. Due to a public database mistake in situ hybridizations were performed for the glutamate transporter GLT1 and demonstrated expression in embryoid bodies, neurospheres and, strikingly, in the SVZ, the neurogenic area of the mouse forebrain. Taken together, this doctoral thesis generated the first gene expression profile for PSA+ neuronal precursors, which -together with the SAGE library for Bruce-4 ES cells- will serve as a starting basis for future functional analysis

Dopamine-modulated dynamic cell assemblies generated by the GABAergic striatal microcircuit

The striatum, the principal input structure of the basal ganglia, is crucial to both motor control and learning. It receives convergent input from all over the neocortex, hippocampal formation, amygdala and thalamus, and is the primary recipient of dopamine in the brain. Within the striatum is a GABAergic microcircuit that acts upon these inputs, formed by the dominant medium-spiny projection neurons (MSNs) and fast-spiking interneurons (FSIs). There has been little progress in understanding the computations it performs, hampered by the non-laminar structure that prevents identification of a repeating canonical microcircuit. We here begin the identification of potential dynamically-defined computational elements within the striatum. We construct a new three-dimensional model of the striatal microcircuit's connectivity, and instantiate this with our dopamine-modulated neuron models of the MSNs and FSIs. A new model of gap junctions between the FSIs is introduced and tuned to experimental data. We introduce a novel multiple spike-train analysis method, and apply this to the outputs of the model to find groups of synchronised neurons at multiple time-scales. We find that, with realistic in vivo background input, small assemblies of synchronised MSNs spontaneously appear, consistent with experimental observations, and that the number of assemblies and the time-scale of synchronisation is strongly dependent on the simulated concentration of dopamine. We also show that feed-forward inhibition from the FSIs counter-intuitively increases the firing rate of the MSNs. Such small cell assemblies forming spontaneously only in the absence of dopamine may contribute to motor control problems seen in humans and animals following a loss of dopamine cells. (C) 2009 Elsevier Ltd. All rights reserved

Newspaper Article, Why are You at College? February 7, 1975

This article discusses a new student service called PATH and describes the purpose of the program, how it works, and how to get involved with it. Another article titled Readers\u27 Theatre offers program describes the semester\u27s scheduled program titled The Revelation to John .https://scholarsjunction.msstate.edu/ua-reflectors-1965-1975/1055/thumbnail.jp