Some observations on the preference deficits produced by lateral preoptic lesions in the rat.

Following water drprivation, rats with lateral preoptic (LPO) damage lose the normal preference for glucose solutions. Food deprivation reinstates the preference. This dependency is specific to sweet-tasting fluids, and the deficit persists even if thirst is alleviated prior to the preference test. Such rats will drink sweet solutions in response to intravascular fluid depletion, but they are deficient in response to sweet solutions under nondeprived conditions. This last finding in particular suggests that hunger and palatability, as determinants of the response to sweet solutions, may be dissociated by LPO damage.