Abstract
To determine the relative effects of insulin, metrazol and electroconvulsive shocks upon learning to learn 30 successive reversal problems by rats, an enclosed square T-maze was used, with water as incentive after 23 hr. of deprivation. S had to achieve 9 correct out of 10 daily trials before a problem was reversed. 40 adult male rats were equally divided into a control and 3 differently shocked groups. Shocks were administered on 3 alternate days followed by 2 days of rest. Each time, Ss of the 4 groups received respectively 0.5 cc. of saline, 55 mg. of metrazol per kg. of body-weight, one unit of insulin per 20 gm. of body-weight, and an electric current of 50 ma. at 25 v for 150 msec. Convulsion in the insulin group was prevented by an injection of dextrose and potassium chloride. The control was significantly superior to the 3 shocked groups which were remarkably similar or practically identical in their performance during the initial 6 problems. Thereafter, both the non-convulsive (saline and insulin) groups did better than the 2 convulsive groups either in terms of error, day, or one-trial reversal score.