The relation between cortical response to visual stimulation and changes in the alpha rhythm.

Abstract

Electrograms of the rabbit''s optic cortex were examined for modification in the [alpha] rhythm when the eye was stimulated by various rates of light flashes. These records, as well as cortical records taken under other conditions, indicate that 2 different groups of elements are responsible for 2 of the prominent features of the cortical records. The activity of 1 group is manifested in the specific cortical response to the optic nerve discharge and the other is manifested in the later constituents of the complete sequel to stimulation. The latter activity is the [alpha] rhythm and it interacts with the former. The "blocking" of the [alpha] rhythm was not the inhibition of the activity of the [alpha] elements but rather a dispersal of their activity so as statistically to smooth out their differences in sign and produce a waveless record. Adaptation is a concept whose justification is not yet apparent in dealing with the rhythm.