Behavior related to trained increase in visual cortex excitability

Operant conditioning techniques were utilized to train cats to increase the amplitude of the short latency (5 msec) cortical response evoked by electrical stimulation of the optic radiation fibers. The cats learned to produce larger evoked potentials, and two distinctly different behaviors were associated with such increase. The first was a general relaxation of skeletal activity. The second was a brisk movement of the head, associated with a transient increase in excitability, lasting several hundred msec, with the maximum effect occurring about 250 msec after a warning stimulus.