The role of the lateral parabrachial nuclei in concurrent and sequential taste aversion learning in rats

Abstract

The purpose of this study was to examine the role of the external lateral parabrachial subnucleus (PBNLe) in two different taste aversion learning (TAL) procedures. For the first, short-term (concurrent) TAL, two different-flavored stimuli were presented at the same time, one associated with simultaneous intragastric administration of an aversive product, hypertonic NaCl, and the other with saline. In the second, long-term (sequential/delayed) TAL, each gustatory stimulus was presented every other day and the intragastric products LiCl and saline were administered after a 15-min delay. Electrolytic lesions in the PBNLe blocked acquisition of concurrent TAL, in which the vagal visceral information is critical. But the same lesions failed to interrupt sequential TAL. This result was independent of the order in which the two tasks (concurrent and sequential) were presented. However, as found by other authors, the latter type of learning was impaired in the presence of larger lesions in this same area. This supports the existence of sensory information needed to establish sequential TAL in other subnuclei of the parabrachial complex. The results of these experiments suggest that the different modalities of TAL are anatomically specific.

Tiapride prevents the aversive but not the rewarding effect induced by parabrachial electrical stimulation in a place preference task

“…The present findings also confirm that tiapride administration impairs the place aversion induced by NLPBe electrical stimulation (Hurtado et al 2014), while the utilization of a higher tiapride dose (40 mg/kg) allowed a dose-response curve to be constructed, suggesting a DA-receptor drug window for the aversive behavior rather than adverse associated heterogeneous actions, which would also have been observed in the positive group, which was not the case. These data are consistent with previous observations by our group that the NLPBe forms part of a brain pathway underlying concurrent taste learning (Mediavilla et al 2000(Mediavilla et al , 2005. Thus, specific lesions of this subnucleus were found to impair the acquisition of concurrent taste aversions (Mediavilla et al 2000(Mediavilla et al , 2011, an implicit learning modality that is also interrupted by tiapride administration (Mediavilla et al 2012).…”

“…These data are consistent with previous observations by our group that the NLPBe forms part of a brain pathway underlying concurrent taste learning (Mediavilla et al 2000(Mediavilla et al , 2005. Thus, specific lesions of this subnucleus were found to impair the acquisition of concurrent taste aversions (Mediavilla et al 2000(Mediavilla et al , 2011, an implicit learning modality that is also interrupted by tiapride administration (Mediavilla et al 2012).…”

“…In relation to the CPA, these results are compatible with previous reports that the parabrachial complex as a whole is related to aversive processes (Bernard et al 1994, Nader et al 1996, Mediavilla et al 2000. More specifically, it has been suggested that the NLPBe may play a major role in processing the affective and emotional components of nociception (Gariau and Bernard 2001) or taste (Hajnal and Norgren 2004) and even in generating human feelings of wellbeing or malaise (Balaban andThayer 2001, Schachter 2004).…”

Lesions of the lateral parabrachial area block the aversive component and induced-flavor preference for the delayed intragastric administration of nutrients in rats: Effects on subsequent food and water intake

“…Our data support the proposal of two different mechanisms that explain the consequences of intragastrically administered nutrients (Agü ero et al 1993a,b;Mediavilla et al 2000Mediavilla et al , 2005. One is independent of the LPB, given that the lesioned animals and controls both show aversion to the intragastrically administered nutrients by rejecting the associated gustatory stimulus.…”

Enteral Feeding: Brain-Visceral Interactions in the Processing of Nutrients

“…The vagus nerve-NSTic-LPBe pathway also proved essential for the rapid transmission of nonnutritional visceral information. We found that the vagus nerve [83] and NSTic [139] or LPBe [140] are necessary for concurrent taste aversion learning but not for sequential TAL.…”