Causal influences in primate cerebral cortex during visual pattern discrimination

Anatomical studies of the visual cortex demonstrate the existence of feedfo rward, feedback and lateral pathways among multiple cortical areas. Yet rel atively little evidence has previously been available to show the causal in fluences of these areas on one another during visual information processing . We simultaneously recorded event-related local field potentials (LFPs) fr om surface-to-depth bipolar electrodes at six sites in the ventral region o f the right hemisphere visual cortex in a highly trained macaque monkey dur ing performance of a visual pattern discrimination task. Applying a new sta tistical measure, the short-time directed transfer function (STDTF), to the LFP data set, we charted the changing strength and direction of causal inf luence between these cortical sites on a fraction-of-a-second time scale. W e present results showing, for the first time, the dynamics of distinct fee dforward, feedback and lateral influences in the ventral portion of the pri mate visual cortex during visual pattern processing. NeuroReport 11:2875-28 80 (C) 2000 Lippincott Williams & Wilkins.