Decreased striatal c-Fos accompanies latent inhibition in a conditioned taste aversion paradigm.
Latent inhibition (LI) is a phenomenon whereby previous exposure to a stimulus retards subsequent acquisition of a conditioned response to that stimulus. The present study investigated the neuronal substrates of LI as assessed in a conditioned taste aversion paradigm by comparing regional c-Fos activation in pre- vs. non-pre-exposed animals. The LI paradigm involved a pre-exposure phase in which water-deprived rats were allowed access to either water (non-pre-exposed; NPE) or 5% sucrose (pre-exposed; PE), followed by a conditioning phase in which animals were allowed access to sucrose and subsequently injected with lithium chloride, and a test phase in which animals were allowed access to both sucrose and water. LI was assessed by comparing the %-sucrose consumed in PE and NPE groups on the test day. Two hours following the onset of the test phase, animals were perfused and their brains processed for c-Fos immunohistochemistry. PE animals drank significantly more sucrose on the test day, indicating the presence of LI. PE animals had significantly fewer FLI-positive cells in the striatum than NPE animals; however, no differences were seen in the nucleus accumbens. This difference in FLI was not due to a difference in sucrose consumption on the test day as there was no correlation between c-Fos and amount of sucrose consumed in the PE group. These data are consistent with previous data supporting a role for the striatum in the disruption of LI as assessed by CTA.
Turgeon
Sarah M
SM
Department of Psychology, P.O. Box 5000, Campus Box 2236, Amherst College, Amherst, MA 01002, USA. smturgeon@amherst.edu
Reichstein
David A
DA
D000661:Amphetamine / Q000494:pharmacology; D000818:Animals; D001362:Avoidance Learning / Q000502:physiology*; D003213:Conditioning, Psychological / Q000502:physiology*; D019422:Dietary Sucrose / Q000494:pharmacology; D004298:Dopamine / Q000378:metabolism; D018765:Dopamine Uptake Inhibitors / Q000494:pharmacology; D015536:Down-Regulation / Q000502:physiology*; D004435:Eating / Q000502:physiology; D007150:Immunohistochemistry; D008297:Male; D017072:Neostriatum / Q000166:cytology / Q000378:metabolism*; D009433:Neural Inhibition / Q000502:physiology*; D009474:Neurons / Q000166:cytology / Q000378:metabolism; D009714:Nucleus Accumbens / Q000166:cytology / Q000378:metabolism*; D016760:Proto-Oncogene Proteins c-fos / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012201:Reward; D013649:Taste / Q000502:physiology
D019422:Dietary Sucrose; D018765:Dopamine Uptake Inhibitors; D016760:Proto-Oncogene Proteins c-fos; D000661:Amphetamine; D004298:Dopamine