INFLUENCE OF ATROPINE MICROINJECTION INTO THE RAT MOTOR CORTEX ON ACQUISITION OF MOTOR SKILL

Atropine is known to impede the acquisition of conditioned responses b y neurons of the motor cortex. Does atropine exert influence (and of w hat kind) on acquisition of local movements controlled by neurons of t he motor cortex? In the present study we examined the influence of atr opine microinjections on acquisition of reaching movement in freely mo ving rats. The intracortical pressure injections of atropine (5 meg an d 15 mcg/0.6 mcl/40 s) were made unilaterally into the forearm area of the motor cortex in adult mongrel rats. Hungry rats learned to reach sunflower seeds form a horizontal tube by using the forelimb contralat eral to the injected site. Atropine exerted dose-dependent influence o f the acquisition of the motor skill. All the tested doses depressed t he inhibition of concurrent movements during learning. In addition, th e higher dose of atropine inhibited the initiation of the reaching mov ements. A hypothesis was proposed to explain these differences.