Conditioned responses in the visual cortex of dogs. I. During wakefulness

Repetitive electrical stimulation or double shocks of the optic chiasm were used as cue stimuli for alimentary lever-press in dogs. Changes in evoked potentials recorded from the visual cortex were examined by using 'matrix' and component analysis. Peak-to-peak amplitude of components 4 and 5 (C4-5) increased preceding initiation of the lever-press, whereas component 1 or 2 remained unchanged. The enhancement of C4-5 amplitude was suppressed during extinction and reappeared during the reacquisition phase. Possible artifacts and relation between enhancement of EP and lever-press behavior were discussed. The results demonstrate that the enhancement of C4-5 amplitude before the lever-press initiation is the conditioned response in the central nervous system.