Sensory and motoric components of various forms of learned movement with change in the activity of the cholinergic system of the neostriatum.

The participation of the cholinergic system of the neostriatum in the regulation of sensorily-monitored movements and the differentiation of sensory signals were investigated in 12 Wistar rats, 27 Sprague-Dawley rats, and 6 mongrel dogs, using the following models: 1) the maintenance of learned extension of the forelimb for a specified time (rats); 2) prolonged conditioned reflex flexion of the hind limb (dogs); and 3) active avoidance in a T-maze (rats). It was demonstrated that the injection of carbacholine (0.03 microgram) into the dorsolateral division of the caudate nucleus of the rats does not bring about significant changes in the performance of movements associated with the maintenance of tonus of the forelimb, whereas the injection of carbacholine (0.05-0.1 microgram) into the same division of the caudate nucleus of the dogs improves the realization of movement associated with the maintenance of tonus of the hind limbs. The injection of a blocker of the cholinergic system (scopolamine in the rats and atropine in the dogs) in both the first and the second instance disturbed the performance of the movement by the animals. Bilateral microinjections of carbacholine (0.03 microgram) into the neostriatum of the rats significantly improves the development of a differentiated active avoidance conditioned reflex in a T-maze on the first three days of testing. The differentiation of acoustic signals by dogs also significantly improved against the background of the injection of carbacholine (0.05-0.1 microgram) into the caudate nucleus. Thus, the data obtained in the various behavioral models and different animals suggest that the cholinergic system of the neostriatum participates in the regulation of both motor and sensory mechanisms in connection with the realization of learned movement.