Intrinsic versus extrinsic influences in the development of neuronal maps
Intrinsic versus extrinsic influences in the development of neuronal maps
Accumulating evidence suggests that the plasticity of extrinsic thalamocortical inputs in cortical layer IV may be guided or instructed by earlier plasticity events in the intrinsic, horizontal connections within the extragranular cortical layers. We analyse a rate-based model of the plasticity of a set of extrinsic afferents in the presence of a pre-existing (and fixed) plexus of intrinsic, overall excitatory horizontal connections between a set of target neurons. We determine conditions under which afferent synaptic pattern formation respects this pre-existing lateral structure. We find three broad regimes under which extrinsic afferent plasticity may violate this structure: the initial pattern of extrinsic afferent innervation of the target cells is far from balanced; the gain of the extrinsic afferents greatly exceeds the overall scale of the strength of lateral excitation; the target cell horizontal coupling matrix is sparse. If none of these conditions is satisfied, then extrinsic afferent plasticity respects the pre-existing lateral connectivity, so that afferent synaptic pattern formation conforms to the pattern of lateral excitation.
model, striate cortex, ocular dominance columns, cat, time, critical period, cell, horizontal connections, primary visual-cortex, development, cells, local circuits, cortical maps, plasticity
129-143
Elliott, Terry
b4262f0d-c295-4ea4-b5d8-3931470952f9
7 September 2007
Elliott, Terry
b4262f0d-c295-4ea4-b5d8-3931470952f9
Elliott, Terry
(2007)
Intrinsic versus extrinsic influences in the development of neuronal maps.
Biological Cybernetics, 96 (1), .
(doi:10.1007/s00422-006-0103-7).
Abstract
Accumulating evidence suggests that the plasticity of extrinsic thalamocortical inputs in cortical layer IV may be guided or instructed by earlier plasticity events in the intrinsic, horizontal connections within the extragranular cortical layers. We analyse a rate-based model of the plasticity of a set of extrinsic afferents in the presence of a pre-existing (and fixed) plexus of intrinsic, overall excitatory horizontal connections between a set of target neurons. We determine conditions under which afferent synaptic pattern formation respects this pre-existing lateral structure. We find three broad regimes under which extrinsic afferent plasticity may violate this structure: the initial pattern of extrinsic afferent innervation of the target cells is far from balanced; the gain of the extrinsic afferents greatly exceeds the overall scale of the strength of lateral excitation; the target cell horizontal coupling matrix is sparse. If none of these conditions is satisfied, then extrinsic afferent plasticity respects the pre-existing lateral connectivity, so that afferent synaptic pattern formation conforms to the pattern of lateral excitation.
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Published date: 7 September 2007
Keywords:
model, striate cortex, ocular dominance columns, cat, time, critical period, cell, horizontal connections, primary visual-cortex, development, cells, local circuits, cortical maps, plasticity
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Web & Internet Science
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Local EPrints ID: 266086
URI: http://eprints.soton.ac.uk/id/eprint/266086
ISSN: 0340-1200
PURE UUID: c03007bc-371c-4f12-bc39-1f39e2308fdb
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Date deposited: 09 Jul 2008 11:03
Last modified: 14 Mar 2024 08:20
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Author:
Terry Elliott
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