The role of the external lateral parabrachial subnucleus in flavor preferences induced by predigested food administered intragastrically

Abstract

A study was undertaken of the role of the external lateral parabrachial subnucleus (PBNLe) in flavor preferences induced by the intragastric administration of predigested / cephalic food. These preferences were developed using two different learning procedures, concurrent and sequential. In the concurrent procedure, two different-flavored stimuli were presented at the same time: one stimulus was paired with the simultaneous intragastric administration of partially digested food and the other with physiological saline. In the sequential learning procedure, the two stimuli were presented at alternate sessions. The results showed that PBNLe lesions blocked acquisition of concurrent learning but had no effect on the sequential procedure. In the latter case, both lesioned and control animals showed a strong preference for the gustatory stimulus paired with partially digested food. These results are interpreted in terms of a dual neurobiological system involved in the rewarding effects of visceral signals.