Event-Related Oscillations in Brain Function

Abstract

At the turn of the twentieth century Karl Lashley believed that various parts of the brain are equipotential and that for many functions, virtually any part of the brain could substitute for any other. In contradiction to this hypothesis, subsequent experiments have shown that even highly complex brain functions can be attributed to specific brain areas. Localization does not imply, however, that any specific function is exclusively mediated by only one region of the brain.

Most functions require the integrated action of neurons located in many regions. Localization of function means that certain areas of the brain are more concerned with one kind of function than with others. The existence of a significant difference in the major operating rhythms in occipital or frontal areas gives strong support to the possibility that theta (spontaneous, evoked, induced) and alpha rhythms (spontaneous, evoked, induced) have fundamentally different functional operations. But during some functional states, major operating rhythms can change their functional roles; the nature of the experiment, i.e., tasks, can influence the weight of these functional components on brain rhythms.