Christof Koch

Computation and Neural Systems Program

California Institute of Technology

Much excitement has been generated in the scientific community by electrophysiological techniques of recording from individual neurons in behaving monkeys and other animals that, combined with functional brain imaging in humans, enables us to study the neuronal basis of subjective, conscious experience. Francis Crick and I have argued that the speediest way to achieve measurable progress is to concentrate for now on the neuronal correlates of consciousness, that is, the minimal brain mechanisms responsible for any one specific conscious percept, thought or memory. I will discuss some of the basic anatomical, physiological and psychophysical findings of relevance to the search for the NCC as they relate to visual consciousness and to other modalities. A key experimental strategy is to focus on the difference, at the neuronal level, between those stereotyped and very rapid behavior that can occur in the absence of consciousness (dubbed on-line system by Milner and Goodale) and those that require consciousness. I will discuss relevant research strategies, in particular those that seek to identify the NCC using electrophysiological and molecular techniques.