[The characteristics of the participation of the neostriatal cholinergic system in regulating different forms of defensive behavior].

The effects of microinjections of the cholinergic agonist (carbacholine) into the dorsal part of the neostriatum on discrimination processing of sensory signals were studied in chronic experiments in dogs (instrumental defensive reflex connected with maintenance of flexion posture) and in rats (active avoidance learning in T-maze). It was found that an improvement of discrimination process after carbacholine injections was manifested as an increase in the number of correct responses during acquisition of discriminative avoidance reflex in T-maze (rats) and during differentiation of sound signals in instrumental defensive reaction (dogs). The efficacy of this influences was suggested to be depend on the level of animal learning. We did not shown an improvement of the responses in two cases: 1. When before the microinjections the responses on the defensive and on the discriminative signals did not distinguish; 2. Under total differentiation of signals (e. g. under total learning). In both cases the neostriatum seems to be not involved in behavioral reaction what could be accompanied by low neuronal activity during the these signals action.