Effect of clonazepam and electrolesions of the dorsal and medial raphe nuclei on learning.

The benzodiazepine Clonazepam, as well as electrolesions of the serotoninergic raphe nuclei, dorsalis and medianus, in rats have a learning-facilitating effect using the system of two-way avoidance. The animals with lesions manifest twice higher values of the index for avoidance learning compared with the control animals. In repeated training, the animals treated with Clonazepam in doses of 1 mg/kg for five successive days, show almost twice higher learning index compared with the controls, the index of Clonazepam-treated animals with lesions being four times higher than the controls. Clonazepam-treated animals manifest a higher number of conditioned-reflex avoidance responses compared with the controls throughout the entire 5-day period. Clonazepam-treated rats with raphe lesions reveal a significantly higher number of conditioned-reflex avoidance responses compared with the control group and with the group of Clonazepam-treated animals. Clonazepam-treated animals show a lower number of inadequate avoidance responses compared with the control animals, while in the Clonazepam-treated animals with lesions there are almost no inadequate reactions. The positive effects of Clonazepam and raphe lesions on avoidance training demonstrate the influence of the serotoninergic system on the processes of learning and memory.