Does the Prefrontal Cortex Play an Essential Role in Consciousness? Insights from Intracranial Electrical Stimulation of the Human Brain
Journal of Neuroscience March 10, 2021 Omri Raccah, N. Block, K. Fox
A central debate in philosophy and neuroscience concerns whether prefrontal cortex (PFC) activity is essential for consciousness. This synthesis of research using intracranial electrical stimulation (iES) in humans shows that stimulating only certain prefrontal regions—the orbitofrontal cortex and anterior cingulate cortex—reliably alters conscious experience. In contrast, stimulating anterolateral prefrontal sites, often emphasized by higher-order and global workspace theories, rarely produces reportable changes in consciousness. The variety of iES-elicited effects (emotions, thoughts, olfactory and visual hallucinations) shows no clear relation to the immediate environment, challenging the idea that the PFC is the basis for conscious perception. The findings suggest a specific role for orbitofrontal and anterior cingulate cortices in supporting emotional aspects of conscious experience.