Enhanced visuomotor associative learning following stimulation of α2A-adrenoceptors in the ventral prefrontal cortex in monkeys

The present study investigated the effect of locally infused guanfacine, an alpha(2A)-adrenergic agonist, into the ventral prefrontal cortex (PFv) on visuomotor associative learning. Two monkeys were well trained on a two-problem visuomotor associative task: the monkeys performed movement A if presented with a circle pattern, or movement B if presented with a triangle pattern. For learning of new visuomotor associations, the monkeys were presented with a new set of four patterns in each and every daily session, two of which instructed movement A and the other two movement B. Bilaterally infused guanfacine (2.5 mug/mul; 3 mul on each side) improved the monkeys' ability to learn new visuomotor associations: trials and errors to learning criterion of 90% correct decreased significantly. The monkeys showed an enhanced capability to use win-stay/lose-shift strategy on `repeat trials' and change-stay/change-shift strategy on 'change trials.' The present results indicate that alpha(2A)-adrenoceptor in the PFv is involved in regulating visuomotor associative learning. (C) 2004 Elsevier B.V. All rights reserved.