Electrophysiological evidence for phenomenal consciousness.

Event-related brain potential (ERP) evidence supports two key ideas in Lamme's theory of consciousness. The earliest brain signal linked to visual consciousness appears over the back of the head about 100-200 milliseconds after a stimulus is presented, consistent with recurrent processing in visual cortex. This early signal is largely separate from later brain responses that reflect selective attention and working memory. The findings suggest that phenomenal consciousness of a visual stimulus arises before access consciousness, and that attention and awareness rely on different neural processes.

Study at a glance

Abstract

Abstract Recent evidence from event-related brain potentials (ERPs) lends support to two central theses in Lamme's theory. The earliest ERP correlate of visual consciousness appears over posterior visual cortex around 100-200 ms after stimulus onset. Its scalp topography and time window are consistent with recurrent processing in the visual cortex. This electrophysiological correlate of visual consciousness is mostly independent of later ERPs reflecting selective attention and working memory functions. Overall, the ERP evidence supports the view that phenomenal consciousness of a visual stimulus emerges earlier than access consciousness, and that attention and awareness are served by distinct neural processes.