The course of acquisition of a conditioned response of the occipital alpha rhythm.

Abstract

The acquisition curve for conditioned blocking of the occipital a rhythm of the human E.E.G. was obtained by pairing half the conditioned stimuli (voluntary fist-clenching) with light (unconditioned stimulus), 6 subjects were successfully conditioned. The acquisition curve detd. by measuring the AL index [image] of 2 sec. of record after the fist-clenching in unpaired trials, was found to be an accelerated one, nearly the mirror image of the extinction curve. The curves of acquisition and extinction for E.E.G. conditioning were found similar to those obtained when peripheral responses are conditioned. Conscious "expectancy" played only a limited part in formation of the response, since, after a short reinforcement series, responses were given when the subject was told not to expect light. These responses tended to become extinguished, while there was always a response when light was expected. The similar properties of E.E.G. conditioned responses and peripheral ones indicate a central neuro-physiological parellel of peripheral events, even though the electrical response of the cortex is probably still "peripheral" to the actual locus of the conditioning process.