The White Paper: Wilder Penfield,the Stream of Consciousness,and the Physiology of Mind

ABSTRACT

Wilder Penfield is justly famous for his contributions to our understanding of epilepsy and of the structure-function relationship of the brain. His theory on the relationship of the brain and mind is less well known. Based on the effects of the electrical stimulation of the cortex in conscious patients, Penfield believed that consciousness and mind are functions of what he referred to as the centrencephalic integrating system. This functional system comprised bidirectional pathways between the upper brainstem, the thalami, and the cerebral cortex of both hemispheres, and was the physical substrate from which memory, perception, initiative, will, and judgment arose. It was the source of the stream of consciousness and the physical basis of mind. This paper reviews how Penfield arrived at this conception of the mind-brain relationship. Although Penfield ultimately felt that he had failed in his attempt to unify brain and mind, his work shed new light on the relationship of memory to the mesial temporal structures and to the temporal cortex; and his association of consciousness and the brainstem preceded the conceptualization of the reticular activating system by a generation. In these, as in so many aspects of neurobiology, Penfield was prescient.