Effects of chlordiazepoxide upon spontaneous alternation and the hippocampal electrical activity in white rats
Iwahara, S.; Oishi, H.; Yamazaki, S.; Sakai, K.
Psychopharmacologia 24(4): 496-507
Chlordiazepoxide (CDP) at 20 mg/kg, i. p. reduced the rate of spontaneous alternation in hungry rats on 6 successive trials with no particular reward in a T-maze (Experiment I). The result could not be ascribed simply to the drug-produced changes in running speeds; although alternation is usually assumed to be higher in rate with shorter inter-choice intervals, CDP rats ran slightly faster than saline rats. The same dose of CDP depressed the hippocampal theta activity by decreasing its frequency and facilitating regular fast activity of about 30 Hz which was superimposed on the theta rhythm (Experiment II). The reduction of alternation after CDP was explained in terms of the drug's depressant action upon one of the hippocampal functions, characterized by the theta activity, which is assumed to have a significant role in internal inhibition underlying such behaviors as discrimination reversal, passive avoidance, extinction, frustration, habituation and spontaneous alternation.