We studied the temporal dynamics of shape representation in area V4 of
the alert macaque monkey. Analyses were based on two large stimulus sets,
one equivalent to the 2D shape stimuli used in a previous study of V2, and
the other a set of stereoscopic 3D shape stimuli. As in V2, we found that
information conveyed by individual V4 neurons about the stimuli tended to
be maximal during the initial transient response and generally lower,
albeit statistically significant, afterwards. The population response was
substantially correlated from one stimulus to the next during the
transients, and decorrelated as responses decayed. V4 responses showed
significantly longer latencies than in V2, especially for the 3D stimulus
set. Recordings from area V1 in a single animal revealed temporal dynamic
patterns in response to the 2D shape stimuli that were largely similar to
those in V2 and V4. Together with earlier results, these findings provide
evidence for a distributed process of coarse-to-fine representation of
shape stimuli in the visual cortex.