title: Cognitive demands induce selective hippocampal reorganization: Arc expression in a place and response task.
abstract: Place cells in the hippocampus can maintain multiple representations of a single environment and respond to physical and/or trajectory changes by remapping. Within the hippocampus there are anatomical, electrophysiological, and behavioral dissociations between the dorsal and ventral hippocampus and within dorsal CA1. Arc expression was used to measure the recruitment of ensembles across different hippocampal subregions in rats trained to utilize two different cognitive strategies while traversing an identical trajectory. This behavioral paradigm allowed for the measurement of remapping in the absence of changes in external cues, trajectory traversed (future/past), running speed, motivation, or different stages of learning. Changes in task demands induced remapping in only some hippocampal regions: reorganization of cell ensembles was observed in dorsal CA1 but not in dorsal CA3. Moreover, a gradient was found in the degree of remapping within dorsal CA1 that corresponds to entorhinal connectivity to this region. Remapping was not seen in the ventral hippocampus: neither ventral CA1 nor CA3 exhibited ensemble changes with different cognitive demands. This contrasts with findings of remapping in both the dorsal and ventral dentate gyrus using this task. The results suggest that the dorsal pole of the hippocampus is more sensitive to changes in task demands.
authors.affiliation: Dept. of Psychology, University of Connecticut, Storrs, Connecticut, USA.
authors.forename: Brandy
authors.initials: B
authors.lastname: Schmidt
authors.forename: Elham
authors.initials: E
authors.lastname: Satvat
authors.forename: Melissa
authors.initials: M
authors.lastname: Argraves
authors.forename: Etan J
authors.initials: EJ
authors.lastname: Markus
authors.forename: Diano F
authors.initials: DF
authors.lastname: Marrone
mesh_terms: D000818:Animals; D001931:Brain Mapping; D056547:CA1 Region, Hippocampal / Q000166:cytology / Q000502:physiology; D056654:CA3 Region, Hippocampal / Q000166:cytology / Q000502:physiology; D003598:Cytoskeletal Proteins / Q000096:biosynthesis* / Q000235:genetics; D005786:Gene Expression Regulation; D006624:Hippocampus / Q000166:cytology / Q000502:physiology*; D017404:In Situ Hybridization, Fluorescence; D008297:Male; D018782:Maze Learning / Q000502:physiology*; D009043:Motor Activity; D009419:Nerve Tissue Proteins / Q000096:biosynthesis* / Q000235:genetics; D017966:Pyramidal Cells / Q000378:metabolism*; D011897:Random Allocation; D051381:Rats; D011916:Rats, Inbred F344; D013037:Spatial Behavior
chemical_list: D003598:Cytoskeletal Proteins; D009419:Nerve Tissue Proteins; C092069:activity regulated cytoskeletal-associated protein