Conditioned taste preferences as a measure of brain-stimulation reward in rats

Abstract

Conditioned taste preferences (CTPs) were demonstrated in rats after one, three or five pairings of a novel tasting solution with sessions of intracranial self-stimulation (ICSS). Control groups that experienced single or repeated unpaired presentations of the novel taste or the ICSS did not exhibit such preferences. Although there were no group differences in the absolute size of the CTPs, the resistance of those preferences to extinction reliably increased with the number of novel taste/ICSS pairings. A second experiment was devised to study the effects of changes in ICSS current intensity on the CTPs produced by that ICSS. There were statistically reliable differences in the CTPs produced by Low-Current and High-Current groups. A No-Current control group did not demonstrate a CTP. Taken together these data suggest that the conditioned taste preference is a learned phenomenon analogous to the conditioned taste aversion that occurs following novel taste/illness pairings. The use of the CTP paradigm as a measure of the rewarding nature of intracranial self-stimulation is proposed.