The neuronal representation of information in the human brain

Abstract

The responses of single neurons provide evidence that is essential to understanding what information is encoded in a brain area, and how it is encoded, for the information conveyed by a single neuron is almost independent of that conveyed by others in the same population. The differences in the firing rate response profiles of single neurons to a set of stimuli or events encode most of the information about that stimulus or event. The representation is sparsely distributed, with neurons often having an approximately exponential firing rate distribution, with high firing rates to a few stimuli, and smaller and smaller responses to other stimuli in the set, and no response to most of the stimuli. It is in this way that information about particular stimuli is represented. For example, in the inferior temporal visual cortex, neurons encode in this manner which particular face or object is being shown (Rolls and Treves, 2011). Evidence of this type is crucial to understanding the operation of the brain, for by reading the code from different connected brain areas, it is possible to start to understand what is being performed (or computed) by each brain region. This in turn is important for understanding neurological and psychiatric disorders and their symptoms, and for suggesting treatments based on what each brain region is performing, and developing hypotheses about how each cortical area operates (Rolls, 2008, 2016). Much of the evidence on what is represented in different cortical areas comes from single neuron studies in macaques, including concepts about the roles of cortical areas that correspond to those in humans. The book Single Neuron Studies of the Human Brain - Probing Cognition edited by Fried, Rutishauser, Cerf and Kreiman is therefore important, for it reviews what is now being discovered from recordings from single …