The Human EEG: General Aspects

Abstract

The living brain shows a rhythmic electric activity which can be recorded from the surface of the head. This activity was first observed by Caton (1875; 1877) in Liverpool, in monkeys and rabbits. The first picture of such an activity in a human being was published by Neminsky (1913) which, however, had no major effect on thinking and conceptualization in brain research (for a more detailed report on the early history of EEG research, see Niedermeyer 1993). The real father of EEG research was Hans Berger, professor of psychiatry in Jena. Using various galvanometers, he recorded rhythmic activity from the heads of some individuals. In his first report, published in 1929, he described the alpha waves and the alpha blocking response, and in 13 further reports, up to 1937, and in a monograph (1938), he described many of the basic EEG phenomena (for detailed references, see Christian 1968). He also coined the termnameElektrenkephalogramwhich from the linguistic point of view is more correct than the conventional term “electroencephalogram,’ since the three components of this term are all Greek in origin. This newly discovered EEG became popular among neural scientists, after the prominent British neurophysiologist Adrian, together with Matthews (1934), had confirmed and enlarged Berger’s observations. Interestingly enough, they also found the first hint for interindividual variation in the normal EEG: While Adrian himself showed a classical alpha rhythm, no such rhythm was seen in the EEG of Matthews. He may have had a low-voltage EEG.