[Effect of destruction of midbrain raphe nuclei on elaboration and preservation of heterogeneous conditioned reflexes].

The destruction of the midbrain raphe nuclei in rats results in a gradual drop of serotonin content in the brain. Its moderate drop, which setts in on the eighth day after ablation of the raphe nuclei, is not attended with any disturbance in elaboration of motor alimentary and defensive conditioned reflexes, while the retention of motor alimentary conditioned reflexes is sharply deteriorated. After a sharp reduction of serotonin content in the brain, which is observed on the fifteenth day after the operation, the animals lost their capacity to elaborate either motor alimentary or denfensive conditioned reflexes.