The participation of mediator and peptidergic systems of the brain in conditioned reflex mechanisms.

New data on the significance of mediator and peptidergic systems of the striatal level in the organization of alimentary conditioned reflexes are presented in this report. The role of acetylcholine-, dopamine-, GABA-and P-ergic systems of the caudate nucleus and the amygdala in the realization of positive and negative conditioned reflexes was investigated. The experiments were carried out on dogs with chemotrodes and microelectrodes implanted in subcortical structures. The results of the experiments with microinjections of the relevant substances into individual subcortical structures showed that activation of the same mediator system in various structures may lead to both unidirectional and multidirectional behavioral effects. On the other hand, the activation of various subcortical mediator systems can lead to identical changes in conditioned reflex activity. The effect of the administration of activators or blockers of a subcortical mediator system depends in many ways on the functional state of the nervous system at the moment of administration and on the localization of the microinjection. It is difficult to predict beforehand the role of various subcortical structures in the organization of integrated behavioral acts. The question of the necessity of studying mediator and peptidergic systems of each subcortical structure in order to understand their significance in the mechanisms of the conditioned reflex is raised.