Feedforward origins of response variability underlying contrast invariant orientation tuning in cat visual cortex.

ABSTRACT: Contrast invariant orientation tuning in simple cells of the visual cortex depends critically on contrast dependent trial-to-trial variability in their membrane potential responses. This observation raises the question of whether this variability originates from within the cortical circuit or the feedforward inputs from the lateral geniculate nucleus (LGN). To distinguish between these two sources of variability, we first measured membrane potential responses while inactivating the surrounding cortex, and found that response variability was nearly unaffected. We then studied variability in the LGN, including contrast dependence, and the trial-to-trial correlation in responses between nearby neurons. Variability decreased significantly with contrast, whereas correlation changed little. When

SUBMITTER: Sadagopan S 

PROVIDER: S-EPMC3591513 | biostudies-literature | 2012 Jun

REPOSITORIES: biostudies-literature