title: Functional relationships between the hippocampus and dorsomedial striatum in learning a visual scene-based memory task in rats.
abstract: The hippocampus is important for contextual behavior, and the striatum plays key roles in decision making. When studying the functional relationships with the hippocampus, prior studies have focused mostly on the dorsolateral striatum (DLS), emphasizing the antagonistic relationships between the hippocampus and DLS in spatial versus response learning. By contrast, the functional relationships between the dorsomedial striatum (DMS) and hippocampus are relatively unknown. The current study reports that lesions to both the hippocampus and DMS profoundly impaired performance of rats in a visual scene-based memory task in which the animals were required to make a choice response by using visual scenes displayed in the background. Analysis of simultaneous recordings of local field potentials revealed that the gamma oscillatory power was higher in the DMS, but not in CA1, when the rat performed the task using familiar scenes than novel ones. In addition, the CA1-DMS networks increased coherence at γ, but not at θ, rhythm as the rat mastered the task. At the single-unit level, the neuronal populations in CA1 and DMS showed differential firing patterns when responses were made using familiar visual scenes than novel ones. Such learning-dependent firing patterns were observed earlier in the DMS than in CA1 before the rat made choice responses. The present findings suggest that both the hippocampus and DMS process memory representations for visual scenes in parallel with different time courses and that flexible choice action using background visual scenes requires coordinated operations of the hippocampus and DMS at γ frequencies.
authors.affiliation: Department of Brain and Cognitive Sciences, Seoul National University, Seoul, 151-742, Korea.
authors.forename: Sébastien
authors.identifier: http://orcid.org/0000-0002-8512-4330
authors.initials: S
authors.lastname: Delcasso
authors.affiliation: Center for Synaptic Dysfunctions, Institute for Basic Science, Korea Advanced Institute of Science and Technology, Daejeon, 305-701, Korea, and.
authors.forename: Namjung
authors.initials: N
authors.lastname: Huh
authors.affiliation: Department of Brain and Cognitive Sciences, Seoul National University, Seoul, 151-742, Korea.
authors.forename: Jung Seop
authors.initials: JS
authors.lastname: Byeon
authors.affiliation: Department of Brain and Cognitive Sciences, Seoul National University, Seoul, 151-742, Korea.
authors.forename: Jihyun
authors.initials: J
authors.lastname: Lee
authors.affiliation: Center for Synaptic Dysfunctions, Institute for Basic Science, Korea Advanced Institute of Science and Technology, Daejeon, 305-701, Korea, and Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon, 305-701, Korea.
authors.forename: Min Whan
authors.identifier: http://orcid.org/0000-0002-4145-600X
authors.initials: MW
authors.lastname: Jung
authors.affiliation: Department of Brain and Cognitive Sciences, Seoul National University, Seoul, 151-742, Korea, lee.inah@gmail.com.
authors.forename: Inah
authors.identifier: http://orcid.org/0000-0003-3760-4257
authors.initials: I
authors.lastname: Lee
mesh_terms: D000818:Animals; D056547:CA1 Region, Hippocampal / Q000187:drug effects / Q000502:physiology; D004567:Electrodes, Implanted; D005074:Evoked Potentials, Visual; D018755:GABA Agonists / Q000494:pharmacology; D006624:Hippocampus / Q000187:drug effects / Q000502:physiology*; D007858:Learning / Q000187:drug effects / Q000502:physiology*; D008297:Male; D008568:Memory / Q000187:drug effects / Q000502:physiology*; D017072:Neostriatum / Q000187:drug effects / Q000502:physiology*; D009415:Nerve Net / Q000187:drug effects / Q000502:physiology; D011597:Psychomotor Performance / Q000187:drug effects / Q000502:physiology; D051381:Rats; D020318:Rats, Long-Evans; D011963:Receptors, GABA-A / Q000187:drug effects; D014796:Visual Perception / Q000187:drug effects / Q000502:physiology*
chemical_list: D018755:GABA Agonists; D011963:Receptors, GABA-A
keywords: basal ganglia; decision making; hippocampus; memory; place cells; spatial representation