The effects of electroshock convulsions on double alternation lever-pressing in the white rat.

Abstract

Double alternation lever-pressing to a criterion of 80% accuracy, or better, was established in 2 albino rats. Two other rats learned to make up to 50% correct responses, with partial double alternation and single alternation constituting the most frequent errors. Convulsions, induced by passage of an electric current through the head, caused a breakdown of the habit in all of the rats in the initial stages of the expt. Two rats were given a series of convulsions, induced twice weekly; meanwhile these animals had daily practice in the apparatus. In each rat, the initial reaction to the shock was a sudden breakdown followed by rapid recovery. This was followed by a period of variable or generally poor performance. Finally, both animals again reached criterion and remained there despite the continuance of semi-weekly convulsions. One rat which had never mastered the habit was placed on a schedule of daily shocks. During a period of 19 daily convulsions, this animal performed better than he had for any comparable time prior to the shocks. The convulsions lowered the general activity level of this animal and probably caused a reduction in errors due to overactivity. In the other animals, it is suggested either (1) that the convulsions decreased bodily tonus, thereby impairing performance or (2) that cerebral anoxia induced by the convulsions caused a temporary loss of retention.