Reinforcer revaluation and conditioned place preference.

Conditioned place preference (CPP) tests provide a novel way of testing an animal's ability to respond to direct manipulation of its motivational state. In the first of two studies, rats exhibited an appropriate preference for a place previously paired with either food or fluid, depending on their current motivational state (hungry or thirsty). Preference was independent of the animal's prior exposure to the relevant reinforcer in that motivational state. In the second experiment, a sucrose solution was used to generate a place preference and was subsequently devalued using a LiCl taste aversion procedure. One group (B) received two CTA sessions and two further groups received a single CTA session either with (R), or without (N), a further nonreinforced opportunity to drink sucrose. Group B exhibited a substantial place aversion and a considerable reduction in sucrose consumption in a test following assessment of place preference. A weak place aversion was found in group N and a weak place preference was shown by group R; sucrose consumption in a test following measurement of place preference followed a similar pattern. These two studies indicate that performance on a place preference task is directly sensitive to both shifts in motivational state and reduction in reinforcer value.