The Journal of Neuroscience, January 1, 2003, 23(1):358-366
Experience-Dependent Plasticity Is Impaired in Adult Rat Barrel
Cortex after Whiskers Are Unused in Early Postnatal Life
V.
Rema1,
Michael
Armstrong-James1, 2, and
Ford F.
Ebner1
1 Department of Psychology, Vanderbilt University,
Nashville, Tennessee 37240, and 2 Department of
Neuroscience, Queen Mary Westfield College, University of
London, London E1 4NS, United Kingdom
The capacity of adult barrel cortex to show experience-dependent
plasticity after early restricted neonatal sensory deprivation was
analyzed in barrel field cortex neurons. Selective sensory deprivation
was induced by trimming two whiskers from postnatal day 0 (P0) to P21,
namely, the principal D2 whisker plus one adjacent surround whisker
(D3). At maturity (P90), responses of supragranular (layer
II/III) and barrel (layer IV) neurons, all located in the D2
barrel column, were analyzed for modified responses to the deprived
principal whisker (D2) and the nondeprived (D1) and deprived (D3)
adjacent surround whiskers. For supragranular neurons, the responses to
both principal and surround whiskers were reduced at maturity, whereas
the barrel neurons showed mildly elevated responses to the principal
whisker but a reduced response to the deprived surround whisker. In
normal adult rats, trimming all but the principal D2 whisker and an
adjacent D3 whisker for 3 d (whisker pairing) produced the
expected bias: elevated responses from the intact D3 compared with the
cut D1 whisker in both barrel and supragranular neurons. When the
neonatally deprived D2 and D3 whiskers were paired at maturity, a
similar D3/D1 bias was generated in barrel neurons, but no bias
occurred in supragranular neuron responses. Pairing the maintained D1
and deprived D2 whiskers produced a much greater bias toward D1
compared with the deprived D3 whisker in barrel neurons than in
supragranular neurons. There were minimal effects on response latencies
in layer IV under any of the experimental conditions. These findings
indicate that a restricted period of sensory deprivation in early
postnatal life (1) impairs intracortical relay of deprived inputs from
layer IV to layer II/III in barrel cortex at maturity and (2) degrades receptive field plasticity of the supragranular layer cells but not the
thalamic-recipient barrel neurons.
Key words:
neural plasticity; barrel field cortex; rat; sensory deprivation; cortical development; whisker pairing
Copyright © 2003 Society for Neuroscience 0270-6474/03/231358-09$05.00/0
