It has been clear for almost two decades that cortical
representations in adult animals are not fixed entities,
but rather, are dynamic and are continuously modified
by experience. The cortex can preferentially allocate
area to represent the particular peripheral input sources
that are proportionally most used.
Alterations in cortical representations appear to underlie
learning tasks dependent on the use of the behaviorally
important peripheral inputs that they represent. The
rules governing this cortical representational plasticity
following manipulations of inputs, including learning,
are increasingly well understood. In parallel with developments
in the field of cortical map plasticity, studies of
synaptic plasticity have characterized specific elementary
forms of plasticity, including associative long-term
potentiation and long-term depression of excitatory
postsynaptic potentials.
Investigators have made many important strides toward
understanding the molecular underpinnings of these fundamental
plasticity processes and toward defining the learning
rules that govern their induction. The fields of cortical
synaptic plasticity and cortical map plasticity underlies
cortical map reorganization. Recent experimental and
theoretical work have provided increasingly stronger
support for this hypothesis. The goal of this talk is
to review the fields of synaptic and cortical map plasticity
with an emphasis on the work that attempts to unite
both fields. A second objective is to highlight the
gaps in our understanding of synaptic and cellular mechanisms
underlying cortical representational plasticity.
