title: Why am I lost without dopamine? Effects of 6-OHDA lesion on the encoding of reward and decision process in CA3.
abstract: There is growing evidence that Parkinson's disease, generally characterized by motor symptoms, also causes cognitive impairment such as spatial disorientation. The hippocampus is a critical structure for spatial navigation and receives sparse but comprehensive dopamine (DA) innervation. DA loss is known to be the cause of Parkinson's disease and therefore it has been hypothesized that the associated spatial disorientation could result from hippocampal dysfunction. Because DA is involved in the prediction of reward expectation, it is possible to infer that spatial disorientation in DA depleted subjects results from the loss of the ability to detect the rewarding features within the environment. Amongst hippocampal formation subdivisions, CA3 properties such as the high liability of its place fields make it a serious candidate for interfacing DA reward system and spatial information encoding. We addressed this issue using multiple electrode recordings of CA3 in normal and dopamine depleted rats performing a spatial learning in a Y-maze. Our data confirm that DA is essential to spatial learning as its depletion results in spatial impairments. The present work also shows that CA3 involvement in the detection of spatial feature contextual significance is under DA control. Finally, it also shows that CA3 contributes to the decision making processes of navigation tasks. The data also reveal a lateralization effect of DA depletion underlined by neural correlates.
authors.affiliation: University of Bordeaux, Institut des Maladies Neurodegeneratives UMR 5293, Bordeaux, France; CNRS, Institut des Maladies Neurodegeneratives UMR 5293, Bordeaux, France.
authors.forename: Aude
authors.initials: A
authors.lastname: Retailleau
authors.forename: Cyril
authors.initials: C
authors.lastname: Dejean
authors.forename: Benjamin
authors.initials: B
authors.lastname: Fourneaux
authors.forename: Xavier
authors.initials: X
authors.lastname: Leinekugel
authors.forename: Thomas
authors.initials: T
authors.lastname: Boraud
mesh_terms: D000200:Action Potentials / Q000187:drug effects / Q000502:physiology; D018663:Adrenergic Agents / Q000633:toxicity*; D000818:Animals; D001930:Brain Injuries / Q000139:chemically induced / Q000150:complications / Q000473:pathology; D056654:CA3 Region, Hippocampal / Q000187:drug effects / Q000503:physiopathology*; D003657:Decision Making / Q000187:drug effects / Q000502:physiology*; D004195:Disease Models, Animal; D004298:Dopamine / Q000378:metabolism*; D005106:Exploratory Behavior / Q000187:drug effects / Q000502:physiology; D005508:Food Deprivation; D007839:Functional Laterality; D008297:Male; D018782:Maze Learning / Q000187:drug effects; D016627:Oxidopamine / Q000633:toxicity*; D017378:Quinolinic Acid / Q000633:toxicity; D051381:Rats; D017207:Rats, Sprague-Dawley; D011930:Reaction Time / Q000187:drug effects; D012201:Reward
chemical_list: D018663:Adrenergic Agents; D016627:Oxidopamine; D017378:Quinolinic Acid; D004298:Dopamine
keywords: Behavioral studies; Electrophysiology; Hippocampus; Monoamine; Rats; Spatial navigation