Effects of chlordiazepoxide (librium) on the acquisition and extinction of avoidance responses

Summary

The major purpose of the present experiment was to assess the differential effectiveness of chlordiazepoxide on avoidance response acquisition and extinction. Two groups of rats, one as control and the other treated with chlordiazepoxide were compared on avoidance response acquisition. No significant differences were noted between the two groups, indicating that chlordiazepoxide was not effective in modifying the rate of avoidance response acquisition. The chlordiazepoxide group was then divided into two subgroups, one continued on chlordiazepoxide and the other deprived of chlordiazepoxide for the extinction training. The control group was also divided into two subgroups, one continued as control and the other treated with chlordiazepoxide for the extinction training. These divisions resulted in closely matched subgroups in the number of avoidance response acquisition, making intergroup comparisons of extinction performance possible. This intergroup comparison showed that chlordiazepoxide was effective in modifying the rate and degree of extinction. Less resistance to extinction was shown by the groups specifically treated with chlordiazepoxide during the extinction period, demonstrating that the effectiveness of chlordiazepoxide was confined mainly to the extinction process. These results were evaluated with the view that a conditioned avoidance response is mediated by fear, and an attempt was made to account for the effects of chlordiazepoxide on fear upon which the condition avoidance response is thought to depend.