Preference conditioning alters taste responses in the nucleus of the solitary tract of the rat.
Aversive conditioning has an impact on the neural signal for the gustatory conditioned stimulus (CS). Here, we determined whether the code is also affected by preference conditioning. We paired the taste of MgCl2 (CS+) with intragastric nutrients in some rats (MG), and citric acid (CS+) with nutrients in others (CI). A control group (Control) experienced both tastants without nutrients. Preferences (>90%) developed for each CS+. We recorded responses to 16 taste stimuli in the nucleus of the solitary tract. Responsiveness of acid-oriented neurons to MgCl2 in MG rats was lower than in Controls, and its profile was more distinct from those of acidic and bitter stimuli. Total activity to citric acid was unchanged in CI rats. However, its temporal profile showed a decreased phasic component, making citric acid temporally distinct from nonsugars. Therefore, the responses to both CS+ were modified, each in its own manner, to be more distinct from those of aversive stimuli. The effects of preference conditioning, however, were weaker than those of aversive conditioning.
Giza
B K
BK
Department of Psychology, University of Delaware, Newark 19716, USA.
Ackroff
K
K
McCaughey
S A
SA
Sclafani
A
A
Scott
T R
TR
D000818:Animals; D001522:Behavior, Animal / Q000502:physiology; D019343:Citric Acid / Q000494:pharmacology; D003213:Conditioning, Psychological / Q000502:physiology*; D004327:Drinking Behavior / Q000502:physiology; D004594:Electrophysiology; D005071:Evoked Potentials / Q000502:physiology; D005260:Female; D005518:Food Preferences / Q000502:physiology*; D015636:Magnesium Chloride / Q000494:pharmacology; D009474:Neurons / Q000145:classification / Q000502:physiology; D051381:Rats; D017207:Rats, Sprague-Dawley; D017552:Solitary Nucleus / Q000166:cytology / Q000502:physiology*; D013268:Stimulation, Chemical; D013649:Taste / Q000502:physiology*
D015636:Magnesium Chloride; D019343:Citric Acid