Modélisation de l'intégration des entrées synaptiques excitatrices chez les cellules thalamocorticales

Authors: Lajeunesse, Francis
Advisor: Kröger, HelmutTimofeev, Igor
Abstract: Thalamocortical (TC) cells from the ventroposterolateral (VPL) nucleus of the thalamus relay the somatosensory inputs (excitatory lemniscal synapses at proximal dendrites) to the corresponding cortical area, but also receive feedback excitatory inputs from the cortex (corticothalamic synapses at distal dendrites). The goal of this study was to compare the synaptic integration of inputs coming to proximal vs. distal dendrites. A multicompartmental model was drawn from fully reconstructed cells of the VPL nucleus. Dendrites were spatially discretized in multiple segments associated to interconnected RC circuits. We were able to characterize the impact of neuronal size and dendritic diameter on the amplitude and on the time course of the somatic response. We also compared the synaptic integration for different distributions of proximal or distal inputs under different conditions of membrane potential and active properties. In all cases, the summation of proximal inputs was independent of their distribution, while the response induced by distal inputs saturated when those inputs were located at the same branches. The results obtained in this study suggest a physiological explanation of the synaptic pattern at TC cells.
Document Type: Mémoire de maîtrise
Issue Date: 2011
Open Access Date: 18 April 2018
Grantor: Université Laval
Collection:Thèses et mémoires

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