Involvement of the supramammillary nucleus in aversive conditioning.
Mechanisms for the retention and retrieval of conditioned taste aversions (CTAs) have yet to be fully defined. The authors explored relevant subcortical forebrain regions by tracking the expression of immediate early genes, c-fos and zif268. The supramammillary nucleus (SuM) was activated following both viscerally based CTA and somatically based inhibitory avoidance (IA). Excitotoxic lesions of the SuM before conditioning caused no disruption of acquisition but accelerated the extinction of both the CTA and IA. In contrast, lesions after CTA conditioning did not impair retention or retrieval. The present study indicates that the SuM is activated by memory-elicited discomfort during retrieval, suggesting that it plays a role in resisting the extinction of a long-term aversive memory.
Yasoshima
Yasunobu
Y
Department of Behavioral Physiology, Graduate School of Human Sciences, Osaka University, Japan. yasosima@fmu.ac.jp
Scott
Thomas R
TR
Yamamoto
Takashi
T
D000704:Analysis of Variance; D000818:Animals; D001362:Avoidance Learning / Q000502:physiology*; D001522:Behavior, Animal; D002452:Cell Count / Q000379:methods; D003214:Conditioning, Classical / Q000502:physiology*; D051766:Early Growth Response Protein 1 / Q000378:metabolism; D004597:Electroshock / Q000379:methods; D005108:Extinction, Psychological / Q000502:physiology; D005786:Gene Expression Regulation / Q000502:physiology; D007150:Immunohistochemistry / Q000379:methods; D018021:Lithium Chloride / Q000494:pharmacology; D008297:Male; D008326:Mammillary Bodies / Q000293:injuries / Q000502:physiology*; D016760:Proto-Oncogene Proteins c-fos / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D011930:Reaction Time / Q000187:drug effects; D013649:Taste / Q000502:physiology*
D051766:Early Growth Response Protein 1; C486110:Egr1 protein, rat; D016760:Proto-Oncogene Proteins c-fos; D018021:Lithium Chloride