[The characteristics of the effect of the rat neostriatal cholinergic system on normal active avoidance learning and in destruction of the intralaminar thalamic nuclei].

The learning of discriminative avoidance reflex in T-maze was studied on 57 Sprague-Dawley rats (divided into several experimental groups) at the normal conditions, both after carbacholine (0.03 mkg), or scopolamine (0.3 mkg) microinjections into neostriatum bilaterally, after uni- or bilateral lesions of intralaminar thalamic nucleus (Pf) and after neostriatal microinjections followed Pf lesion. It has been shown that bilateral carbacholine microinjections in neostriatum (in 4, 5 and 6 days of learning) significantly increased (p < 0.01) the level of correct realizations of discriminative avoidance reflex. Bilateral lesion of Pf resulted in irreversible destruction of preliminary learned active avoidance movement. In rats with preliminary lesion of Pf nuclei we had no possibility of learn discriminative avoidance reflex during 10 experimental days (160 trials). The neostriatal carbacholine microinjections to these animals didn't show any effect. It was concluded that intact afferent input from Pf nucleus is significant for activation of neostriatal neuronal background, necessary for cholinergic activation effect.