Bi-directional interactions between visual areas in the awake behaving cat

The study of the cooperativity among cortical areas is essential to our und erstanding of brain functioning. Here we investigated the relative contribu tions of top-down and bottom-up directed interactions between area 17 and a rea 7 of the cat visual system. Bipolar local field potentials were recorde d while the animals performed a go/no-go task or were in a quiet resting st ate. The data were analyzed by applying measures of interaction based on th e Wiener-Granger causality concept. We found that during the visual task to p-down directed interactions were of a similar magnitude as the bottom-up c omponent. Second, interareal couplings tended to increase in conditions req uiring a discriminative effort. Third, during behaviors not dominated by vi sual processing non-directed interactions increased. NeuroReport 11:689-692 (C) 2000 Lippincott Williams & Wilkins.