The functional relevance of medial parabrachial nucleus in intragastric sodium chloride-induced short-term (concurrent) aversion learning.
The functional meaning of the visceral information processing in the medial parabrachial nucleus (PBNm) was analyzed in this study through a short-term aversion learning task. In this short-term task the animals (Wistar rats) had to learn to discriminate between two different gustatory-olfactory stimuli presented simultaneously (two graduated burettes); one of the stimuli was associated with the concurrent intragastric administration of an aversive chemical agent (hypertonic NaCl) and the other stimulus was paired with no injection. In the first experiment, the PBNm-lesioned animals are unable to learn the task using gustatory stimuli (saccharin and quinine) that surpassed the detection threshold of parabrachial-lesioned rats. Moreover, in a second experiment, the PBNm-lesioned animals were unable to learn the task when there was no initial preference for either of the gustatory-olfactory stimuli presented (strawberry or coconut). However, this short-term task is learned by lateral parabrachial nucleus (PBNl) lesioned animals. The possibility that the PBNm and the PBNl are involved in distinct mechanisms of visceral processing is discussed.
Agüero
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A
Departamento de Psicología Experimental y Fisiología del Comportamiento, Universidad de Granada, Spain. aaguero@piturda.ujaen.es
Gallo
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M
Arnedo
M
M
Molina
F
F
Puerto
A
A
D000818:Animals; D001921:Brain / Q000187:drug effects*; D003213:Conditioning, Psychological / Q000187:drug effects*; D004435:Eating / Q000187:drug effects*; D007858:Learning / Q000502:physiology*; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D012965:Sodium Chloride / Q000008:administration & dosage / Q000494:pharmacology*; D013997:Time Factors
D012965:Sodium Chloride