Intracortical generators of the flash VEP in monkeys

摘要: Flash visual evoked potentials (VEPs) in unanesthetized monkeys were recorded from the cortical surface and closely spaced intracortical sites together with associated multiple unit activity (MUA). The VEP depth profiles subjected to current source density (CSD) analysis delineate laminar pattern of transmembrane flows manifested by extracellular sinks. initial components (P15 P18) generated subcortically within thalamocortical radiations. distribution sources sinks two subsequent negative components. N24 N40. demonstrates their generation laminae IVA IVCb respectively, both parvocellular thalamorecipient layers. Oscillatory resembling those seen human VEPs are observed riding on N40; MUA conjunction coincident these wavelets provides evidence that they derive activity. 20-60 msec range shows phasic increases throughout lamina IV, which maximum amplitude IVA. This increased firing is concurrent sublaminae A component, P65, a decrease below spontaneous level co-located source, probably arises intracortically inhibitory IVCb. next potential at 95 msec, III, consistent stellate cell input supragranular elements. after N95 not either or CSD extrastriate cortex. Human counterparts simian proposed.