Electroencephalographic individual differences and their constancy: I. During sleep.

Abstract

A-rhythms were recorded in 20 c? adult subjects, 5 representing each of the 4 types known as rare, mixed, subdominant, and dominant a, (1) under the standard waking condition of minimal activity. (2) during all-night sleep, and (3) during psychological activity of diverse types. The fact that this population was heterogeneous with respect to waking a index (the % of time an a rhythm was present on the record) prior to sleep, but homogeneous with respect to all sleep rhythms, and not heterogeneous as before sleep as regards waking a index after sleep, is taken to signify that individual differences in regard to a characteristics are not to be ascribed merely to a fixed inborn cortical organization.