CONTRIBUTION OF GABAERGIC INHIBITION TO SENSITIVITY TO CROSS-LIKE FIGURES IN STRIATE CORTEX

MANY neurons in the cat primary visual cortex are sensitive to crucifo rm and corner figures consisting of two oriented lines. To determine t he contribution of inhibition to this property we investigated 85 V1 n eurons before and after local blockade of GABAergic inhibition by micr oiontophoretic application of bicuculline. Cross sensitivity was gener ated or enhanced by inhibition in roughly 1/3 and suppressed or dimini shed in another 1/3 of the cells. In the remaining 1/3 cross sensitivi ty was either absent or not influenced by inhibition. The results demo nstrate a substantial contribution of intracortical inhibition to eith er establish sharp single bar orientation tuning or to generate or mod ulate the sensitivity of visual cortical neurons to line crossings. (C ) 1998 Lippincott Williams & Wilkins.