The Experts below are selected from a list of 105 Experts worldwide ranked by ideXlab platform
Paul L A Gabbott - One of the best experts on this subject based on the ideXlab platform.
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subpial fan Cell a class of calretinin neuron in layer 1 of adult monkey prefrontal cortex
Frontiers in Neuroanatomy, 2016Co-Authors: Paul L A GabbottAbstract:Layer 1 of the cortex contains populations of neurochemically distinct neurons and afferent fibres which markedly affect neural activity in the apical dendritic tufts of pyramidal Cells. Understanding the causal mechanisms requires knowledge of the Cellular architecture and synaptic organisation of layer 1. This study has identified 8 morphological classes of calretinin immunopositive (CRet+) neurons (including Cajal-Retzius Cells) in layer 1 of the prefrontal cortex (PFC) in adult monkey (Macaca fasicularis), with a distinct class - termed ‘subpial fan (SPF) Cell’ - described in detail. SPF Cells were rare horizontal unipolar CRet+ Cells located directly beneath the pia with a single thick primary dendrite that branched into a characteristic fan-like dendritic tree tangential to the pial surface. Dendrites had spines, filamentous processes and thorny branchlets. SPF Cells lay millimetres apart with axons that ramified widely in upper layer 1. Such Cells were GABA immunonegative (-) and occurred in areas beyond PFC. Interspersed amidst SPF Cells displaying normal structural integrity were degenerating CRet+ neurons (including SPF Cells) and clumps of lipofuscin-rich Cellular debris. The number of degenerating SPF Cells increased during adulthood. Ultrastructural analyses indicated SPF Cell somata received asymmetric (A - presumed excitatory) and symmetric (S - presumed inhibitory) synaptic contacts. Proximal dendritic shafts received mainly S-type and distal shafts mostly A-type input. All dendritic thorns and most dendritic spines received both synapse types. The tangential areal density of SPF Cell axonal varicosities varied radially from parent somata - with dense clusters in more distal zones. All boutons formed A-type contacts with CRet- structures. The main post-synaptic targets were dendritic shafts (67%; mostly spine-bearing) and dendritic spines (24%). SPF-SPF Cell innervation was not observed. Morphometry of SPF Cells indicated a unique class of CRet+/GABA- neuron in adult monkey PFC – possibly a subtype of persisting Cajal-Retzius Cell. The distribution and connectivity of SPF Cells suggest they act as integrative hubs in upper layer 1 during postnatal maturation. The main synaptic output of SPF Cells likely provides a transminicolumnar excitatory influence across swathes of apical dendritic tufts - thus affecting information processing in discrete patches of layer 1 in adult monkey
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‘Subpial fan Cell’ – a class of calretinin neuron in layer 1 of adult monkey prefrontal cortex.
Frontiers Media S.A., 2016Co-Authors: Paul L A GabbottAbstract:Layer 1 of the cortex contains populations of neurochemically distinct neurons and afferent fibres which markedly affect neural activity in the apical dendritic tufts of pyramidal Cells. Understanding the causal mechanisms requires knowledge of the Cellular architecture and synaptic organisation of layer 1. This study has identified 8 morphological classes of calretinin immunopositive (CRet+) neurons (including Cajal-Retzius Cells) in layer 1 of the prefrontal cortex (PFC) in adult monkey (Macaca fasicularis), with a distinct class - termed ‘subpial fan (SPF) Cell’ - described in detail.SPF Cells were rare horizontal unipolar CRet+ Cells located directly beneath the pia with a single thick primary dendrite that branched into a characteristic fan-like dendritic tree tangential to the pial surface. Dendrites had spines, filamentous processes and thorny branchlets. SPF Cells lay millimetres apart with axons that ramified widely in upper layer 1. Such Cells were GABA immunonegative (-) and occurred in areas beyond PFC. Interspersed amidst SPF Cells displaying normal structural integrity were degenerating CRet+ neurons (including SPF Cells) and clumps of lipofuscin-rich Cellular debris. The number of degenerating SPF Cells increased during adulthood. Ultrastructural analyses indicated SPF Cell somata received asymmetric (A - presumed excitatory) and symmetric (S - presumed inhibitory) synaptic contacts. Proximal dendritic shafts received mainly S-type and distal shafts mostly A-type input. All dendritic thorns and most dendritic spines received both synapse types. The tangential areal density of SPF Cell axonal varicosities varied radially from parent somata - with dense clusters in more distal zones. All boutons formed A-type contacts with CRet- structures. The main post-synaptic targets were dendritic shafts (67%; mostly spine-bearing) and dendritic spines (24%). SPF-SPF Cell innervation was not observed. Morphometry of SPF Cells indicated a unique class of CRet+/GABA- neuron in adult monkey PFC – possibly a subtype of persisting Cajal-Retzius Cell. The distribution and connectivity of SPF Cells suggest they act as integrative hubs in upper layer 1 during postnatal maturation. The main synaptic output of SPF Cells likely provides a transminicolumnar excitatory influence across swathes of apical dendritic tufts - thus affecting information processing in discrete patches of layer 1 in adult monke
A Pierani - One of the best experts on this subject based on the ideXlab platform.
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ExtraCellular Pax6 Regulates Tangential Cajal-Retzius Cell Migration in the Developing Mouse Neocortex
Cerebral Cortex, 2019Co-Authors: H Kaddour, E. Coppola, Ariel Di Nardo, C Le Poupon, P. Mailly, A. Wizenmann, M. Volovitch, A Prochiantz, A PieraniAbstract:The embryonic mouse cortex displays a striking low caudo-medial and high rostro-lateral graded expression of the homeoprotein transcription factor Pax6, which presents both Cell autonomous and direct nonCell autonomous activities. Through the genetic induction of anti-Pax6 single-chain antibody secretion, we have analyzed Pax6 nonCell autonomous activity on the migration of cortical hem-and septum-derived Cajal-Retzius (CR) neurons by live imaging of f lat mount developing cerebral cortices. Blocking extraCellular Pax6 disrupts tangential CR Cell migration patterns by decreasing the distance traveled and changing both directionality and depth at which CR Cells migrate. Tracking of single CR Cells in mutant cortices revealed that extraCellular Pax6 neutralization enhances contact repulsion in medial regions yet reduces it in lateral regions. This study demonstrates that secreted Pax6 controls neuronal migration and distribution and suggests that it acts as a bona fide morphogen at an early stage of cerebral cortex development.
David R Beier - One of the best experts on this subject based on the ideXlab platform.
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reelin mediates hippocampal cajal retzius Cell positioning and infrapyramidal blade morphogenesis
Journal of Developmental Biology, 2020Co-Authors: Prem Prakash Tripathi, Ray A M Daza, Robert F Hevner, David R BeierAbstract:We have previously described hypomorphic reelin (Reln) mutant mice, RelnCTRdel, in which the morphology of the dentate gyrus is distinct from that seen in reeler mice. In the RelnCTRdel mutant, the infrapyramidal blade of the dentate gyrus fails to extend, while the suprapyramidal blade forms with a relatively compact granule neuron layer. Underlying this defect, we now report several developmental anomalies in the RelnCTRdel dentate gyrus. Most strikingly, the distribution of Cajal-Retzius Cells was aberrant; Cajal-Retzius neurons were increased in the suprapyramidal blade, but were greatly reduced along the subpial surface of the prospective infrapyramidal blade. We also observed multiple abnormalities of the fimbriodentate junction. Firstly, progenitor Cells were distributed abnormally; the "neurogenic cluster" at the fimbriodentate junction was absent, lacking the normal accumulation of Tbr2-positive intermediate progenitors. However, the number of dividing Cells in the dentate gyrus was not generally decreased. Secondly, a defect of secondary glial scaffold formation, limited to the infrapyramidal blade, was observed. The densely radiating glial fibers characteristic of the normal fimbriodentate junction were absent in mutants. These fibers might be required for migration of progenitors, which may account for the failure of neurogenic cluster formation. These findings suggest the importance of the secondary scaffold and neurogenic cluster of the fimbriodentate junction in morphogenesis of the mammalian dentate gyrus. Our study provides direct genetic evidence showing that normal RELN function is required for Cajal-Retzius Cell positioning in the dentate gyrus, and for formation of the fimbriodentate junction to promote infrapyramidal blade extension.
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reelin mediates hippocampal cajal retzius Cell positioning and infrapyramidal blade morphogenesis
bioRxiv, 2019Co-Authors: Prem Prakash Tripathi, Ray A M Daza, Robert F Hevner, David R BeierAbstract:We have previously described hypomorphic reelin (Reln) mutant mice, RelnCTRdel, in which the morphology of the dentate gyrus is distinct from that seen in reeler mice. In the RelnCTRdel mutant the infrapyramidal blade of the dentate gyrus fails to extend, while the suprapyramidal blade forms with a relatively compact granule neuron layer. The distribution of Cajal-Retzius Cells in the dentate gyrus was aberrant; Cajal-Retzius neurons were increased in the suprapyramidal blade, but were greatly reduced along the subpial surface of the prospective infrapyramidal blade. We also observed multiple abnormalities of the fimbriodentate junction. Firstly, progenitor Cells were distributed abnormally; the neurogenic cluster at the fimbriodentate junction was absent, lacking the normal accumulation of Tbr2-positive intermediate progenitors. However, the number of dividing Cells in the dentate gyrus was not generally decreased. Secondly, a defect of secondary glial scaffold formation, limited to the infrapyramidal blade, was observed. The densely radiating glial fibers characteristic of the normal fimbriodentate junction were absent in mutants. These fibers might be required for migration of progenitors, which may account for the failure of neurogenic cluster formation. These findings suggest the importance of the secondary scaffold and neurogenic cluster of the fimbriodentate junction in morphogenesis of the mammalian dentate gyrus. Our study provides direct genetic evidence showing that normal RELN function is required for Cajal-Retzius Cell positioning in the dentate gyrus, and for formation of the fimbriodentate junction to promote infrapyramidal blade extension.
Gianmaria Maccaferri - One of the best experts on this subject based on the ideXlab platform.
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Cajal-Retzius Cells and GABAergic interneurons of the developing hippocampus: Close electrophysiological encounters of the third kind.
Brain research, 2018Co-Authors: Max Anstötz, Giulia Quattrocolo, Gianmaria MaccaferriAbstract:Abstract In contrast to the large number of studies investigating the electrophysiological properties and synaptic connectivity of hippocampal pyramidal neurons, granule Cells, and GABAergic interneurons, much less is known about Cajal-Retzius Cells. In this review article, we discuss the possible reasons underlying this difference, and review experimental work performed on this Cell type in the hippocampus, comparing it with results obtained in the neocortex. Our main emphasis is on data obtained with in vitro electrophysiology. In particular, we address the bidirectional connectivity between Cajal-Retzius Cells and GABAergic interneurons, examine their synaptic properties and propose specific functions of Cajal-Retzius Cell/GABAergic interneuron microcircuits. Lastly, we discuss the potential involvement of these microcircuits in critical physiological hippocampal functions such as postnatal neurogenesis or pathological scenarios such as temporal lobe epilepsy.
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Experience-Dependent Regulation of Cajal-Retzius Cell Networks in the Developing and Adult Mouse Hippocampus.
Cerebral Cortex, 2017Co-Authors: Max Anstötz, Sun Kyong Lee, Tamra I Neblett, Gabriele M. Rune, Gianmaria MaccaferriAbstract:In contrast to their near-disappearance in the adult neocortex, Cajal-Retzius Cells have been suggested to persist longer in the hippocampus. A distinctive feature of the mature hippocampus, not maintained by other cortical areas, is its ability to sustain adult neurogenesis. Here, we have investigated whether environmental manipulations affecting hippocampal postnatal neurogenesis have a parallel impact on Cajal-Retzius Cells. We used multiple mouse reporter lines to unequivocally identify Cajal-Retzius Cells and quantify their densities during postnatal development. We found that exposure to an enriched environment increased the persistence of Cajal-Retzius Cells in the hippocampus, but not in adjacent cortical regions. We did not observe a similar effect for parvalbumin-expressing interneurons, which suggested the occurrence of a Cell type-specific process. In addition, we did not detect obvious changes either in Cajal-Retzius Cell electrophysiological or morphological features, when compared with what previously reported in animals not exposed to enriched conditions. However, optogenetically triggered synaptic output of Cajal-Retzius Cells onto local interneurons was enhanced, consistent with our observation of higher Cajal-Retzius Cell densities. In conclusion, our data reveal a novel form of hippocampal, Cell type-specific, experience-dependent network plasticity. We propose that this phenomenon may be involved in the regulation of enrichment-dependent enhanced hippocampal postnatal neurogenesis.
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Optogenetic activation of Cajal-Retzius Cells reveals their glutamatergic output and a novel feedforward circuit in the developing mouse hippocampus.
The Journal of neuroscience : the official journal of the Society for Neuroscience, 2014Co-Authors: Giulia Quattrocolo, Gianmaria MaccaferriAbstract:Cajal-Retzius Cells orchestrate the development of cortical circuits by secreting the glycoprotein reelin. However, their computational functions are still unknown. In fact, the nature of their postsynaptic targets, major neurotransmitter released, as well as the class of postsynaptic receptors activated by their firing remain unclear. Here, we have addressed these questions by activating Cajal-Retzius Cells optogenetically in mouse hippocampal slices. Light delivered to stratum lacunosum-moleculare triggered EPSCs both on local interneurons and on pyramidal Cells. Responses recorded under voltage-clamp conditions had identical short latencies and similar amplitudes, but were kinetically different (i.e., faster in interneurons vs pyramidal Cells). In both cases, responses were blocked by TTX, indicating that they were generated by action potential-dependent release. Responses in interneurons were rescued by the addition of 4-AP to TTX, and decreased when presynaptic firing in Cajal-Retzius Cells was reduced by the chemokine CXCL12, indicating the existence of a direct Cajal-Retzius Cell-interneuron monosynaptic connection. Although the combined application of 4-AP and TTX did not rescue responses in pyramidal Cells, neither were they affected by the GABAA receptor blocker gabazine, which would be expected if they were polysynaptic. Both connections showed physiological and pharmacological properties indicating the involvement of AMPA- and NMDA-type glutamate receptors. The connectivity from presynaptic Cajal-Retzius Cells to interneurons was strong enough to generate long-latency feedforward GABAergic input onto pyramidal Cells. We propose that this newly defined Cajal-Retzius Cell-dependent microcircuit may regulate synaptic plasticity and dendritic development in stratum lacunosum-moleculare, thus impacting the integrative properties of the developing hippocampus.
H Kaddour - One of the best experts on this subject based on the ideXlab platform.
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ExtraCellular Pax6 Regulates Tangential Cajal-Retzius Cell Migration in the Developing Mouse Neocortex
Cerebral Cortex, 2019Co-Authors: H Kaddour, E. Coppola, Ariel Di Nardo, C Le Poupon, P. Mailly, A. Wizenmann, M. Volovitch, A Prochiantz, A PieraniAbstract:The embryonic mouse cortex displays a striking low caudo-medial and high rostro-lateral graded expression of the homeoprotein transcription factor Pax6, which presents both Cell autonomous and direct nonCell autonomous activities. Through the genetic induction of anti-Pax6 single-chain antibody secretion, we have analyzed Pax6 nonCell autonomous activity on the migration of cortical hem-and septum-derived Cajal-Retzius (CR) neurons by live imaging of f lat mount developing cerebral cortices. Blocking extraCellular Pax6 disrupts tangential CR Cell migration patterns by decreasing the distance traveled and changing both directionality and depth at which CR Cells migrate. Tracking of single CR Cells in mutant cortices revealed that extraCellular Pax6 neutralization enhances contact repulsion in medial regions yet reduces it in lateral regions. This study demonstrates that secreted Pax6 controls neuronal migration and distribution and suggests that it acts as a bona fide morphogen at an early stage of cerebral cortex development.
