[Effect of serotonin on processes of elaboration and fixation of heterogeneous temporary connections]

The effect of serotonin (5-OT) level in the brain on the elaboration and retention of heterogenous conditioned reflexes was studied in the experiments on rats and mice. Redundancy of 5-OT deteriorated the retention of defensive and alimentary conditioned reflexes and almost fully prevented the fixation of drinking conditioned reflexes. The reduction of 5-OT led to less pronounced disorders in the retention of conditioned reflexes. With a prolonged delay of electrocutaneous reinforcement (from 5 to 10 s) the control animals showed slower elaboration of two-side avoidance reflexes, while their retention was uneffected. The redundancy of 5-OT in these conditions accelerated the elaboration but at the same time deteriorated the retention as in case of 5-second delay. A conclusion is made that with the changed level of 5-OT the impairment of conditioned reflexes retention doesn't depend on the changes in the speed of their elaboration. The "point of application" of changes in 5-OT content lies in the process of the temporary connection consolidation. The degree of 5-OT participation in these processes depends on the characteristics of elaborated conditioned reflexes.