Dopaminergic agonistic and antagonistic drugs in the ventral tegmentum of rats inhibit and facilitate changes of food-search behaviour.

The proposal that an increase of dopaminergic activity in the mesocorticolimbic pathway increases the probability of behavioural change is tested. Rats were trained to search for 4 food pellets in a 16-hole board arena. Groups of rats received lesions of the ventral tegmental area (VTA) or injections of spiroperidol or apomorphine into the VTA after sessions 4 and 7 (max. 9 sessions). Spiroperidol-treated and lesioned animals changed their preferred food-hole visit sequences more often than controls. After session 7 the apomorphine-treated group change less often than controls. It is proposed that increased dopaminergic activity in the mesocorticolimbic pathway facilitates changes of behavioural strategy.