title: Arc visualization of odor objects reveals experience-dependent ensemble sharpening, separation, and merging in anterior piriform cortex in adult rat.
abstract: Visualization using the immediate early gene Arc revealed sparser and more robust odor representations in the anterior piriform cortex of adult rats when odor was associated with water reward over 2-3 d. Rewarded odor "mixtures" resulted in rats responding to either component odor similarly, and, correspondingly, the odor representations became more similar as indexed by increased overlap in piriform Arc-expressing (Arc(+)) pyramidal neurons. The increased overlap was consistent with the rats' generalization from component odors. Discriminating among highly similar odor mixtures for reward led to increased differentiation of the neural representations as indexed by a reduction in overlap for piriform Arc(+) pyramidal neurons after training. Similar odor mixture discrimination also required more trials to criterion. The visible reduction in the overlap of odor representations indexes pattern separation. The Arc visualization of odor representations in the anterior piriform network suggests that odor objects are widely distributed representations and can be rapidly modified by reward training in adult rats. We suggest that dynamic changes such as those observed here in piriform odor encoding are at the heart of perceptual learning and reflect the continuing plastic nature of mature associative cortex as an outcome of successful problem solving.
authors: Biomedical Sciences, Faculty of Medicine and.
authors: Amin Md
authors: AM
authors: Shakhawat
authors: Department of Psychology, Faculty of Science, Memorial University of Newfoundland, St. John's, Newfoundland, Canada, A1B 3V6.
authors: Carolyn W
authors: CW
authors: Harley
authors: Biomedical Sciences, Faculty of Medicine and qi.yuan@med.mun.ca.
authors: Qi
authors: Q
authors: Yuan
mesh_terms: D000818:Animals; D001245:Association Learning; D002540:Cerebral Cortex / Q000502:physiology*; D003598:Cytoskeletal Proteins / Q000235:genetics / Q000378:metabolism; D004193:Discrimination Learning / Q000502:physiology*; D005260:Female; D005786:Gene Expression Regulation / Q000502:physiology; D008297:Male; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism; D009812:Odorants; D009833:Olfactory Pathways / Q000502:physiology*; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D012903:Smell / Q000502:physiology*; D014868:Water Deprivation / Q000502:physiology
chemical_list: D003598:Cytoskeletal Proteins; D009419:Nerve Tissue Proteins; D012333:RNA, Messenger; C092069:activity regulated cytoskeletal-associated protein
keywords: Arc; catFISH; olfactory coding; olfactory learning; pattern separation; piriform