  We would like to know whether the statistics of neuronal responses vary
across cortical areas. We examined stimulus-elicited spike count response
distributions in V1 and IT cortices of awake monkeys. In both areas the
distribution of spike counts for each stimulus was well-described by a
Gaussian, with the log of the variance in the spike count linearly related to
the log of the mean spike count. Two significant differences in response
characteristics were found: both the range of spike counts and the slope of the
log(variance) vs. log(mean) regression were larger in V1 than in IT. However,
neurons in the two areas transmitted approximately the same amount of
information about the stimuli, and had about the same channel capacity (the
maximum possible transmitted information given noise in the responses). These
results suggest that neurons in V1 use more variable signals over a larger
dynamic range than neurons in IT, which use less variable signals over a
smaller dynamic range. The two coding strategies are approximately as effective
in transmitting information.
