A Neural Field Model of the Somatosensory Cortex: Formation, Maintenance and Reorganization of Ordered Topographic Maps
PLoS ONE. 2012-07-12; 7(7): e40257
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1. PLoS One. 2012;7(7):e40257. doi: 10.1371/journal.pone.0040257. Epub 2012 Jul 12.
A neural field model of the somatosensory cortex: formation, maintenance and
reorganization of ordered topographic maps.
Detorakis GI(1), Rougier NP.
(1)INRIA CNRS UMR 7503 Université Henri Poincaré – Nancy I Université Nancy II
Institut National Polytechnique de Lorraine, Nancy, France.
We investigate the formation and maintenance of ordered topographic maps in the
primary somatosensory cortex as well as the reorganization of representations
after sensory deprivation or cortical lesion. We consider both the critical
period (postnatal) where representations are shaped and the post-critical period
where representations are maintained and possibly reorganized. We hypothesize
that feed-forward thalamocortical connections are an adequate site of plasticity
while cortico-cortical connections are believed to drive a competitive mechanism
that is critical for learning. We model a small skin patch located on the distal
phalangeal surface of a digit as a set of 256 Merkel ending complexes (MEC) that
feed a computational model of the primary somatosensory cortex (area 3b). This
model is a two-dimensional neural field where spatially localized solutions
(a.k.a. bumps) drive cortical plasticity through a Hebbian-like learning rule.
Simulations explain the initial formation of ordered representations following
repetitive and random stimulations of the skin patch. Skin lesions as well as
cortical lesions are also studied and results confirm the possibility to
reorganize representations using the same learning rule and depending on the type
of the lesion. For severe lesions, the model suggests that cortico-cortical
connections may play an important role in complete recovery.
PMID: 22808127 [Indexed for MEDLINE]