title: Dissociating context and space within the hippocampus: effects of complete, dorsal, and ventral excitotoxic hippocampal lesions on conditioned freezing and spatial learning.
abstract: Rats with complete excitotoxic hippocampal lesions or selective damage to the dorsal or ventral hippocampus were compared with controls on measures of contextually conditioned freezing in a signaled shock procedure and on a spatial water-maze task. Complete and ventral lesions produced equivalent, significant anterograde deficits in conditioned freezing relative to both dorsal lesions and controls. Complete hippocampal lesions impaired water-maze performance; in contrast, ventral lesions improved performance relative to the dorsal group, which was itself unexpectedly unimpaired relative to controls. Thus, the partial lesion effects seen in the 2 tasks never resembled each other. Anterograde impairments in contextual freezing and spatial learning do not share a common underlying neural basis; complete and ventral lesions may induce anterograde contextual freezing impairments by enhancing locomotor activity under conditions of mild stress.
authors.affiliation: Department of Experimental Psychology, Oxford University, England.
authors.forename: M A
authors.initials: MA
authors.lastname: Richmond
authors.forename: B K
authors.initials: BK
authors.lastname: Yee
authors.forename: B
authors.initials: B
authors.lastname: Pouzet
authors.forename: L
authors.initials: L
authors.lastname: Veenman
authors.forename: J N
authors.initials: JN
authors.lastname: Rawlins
authors.forename: J
authors.initials: J
authors.lastname: Feldon
authors.forename: D M
authors.initials: DM
authors.lastname: Bannerman
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D003214:Conditioning, Classical / Q000187:drug effects / Q000502:physiology*; D018691:Excitatory Amino Acid Antagonists / Q000008:administration & dosage; D005239:Fear / Q000187:drug effects / Q000502:physiology*; D006624:Hippocampus / Q000187:drug effects / Q000293:injuries / Q000502:physiology*; D007103:Immobilization / Q000502:physiology*; D008297:Male; D018782:Maze Learning / Q000502:physiology*; D008845:Microinjections; D016202:N-Methylaspartate / Q000008:administration & dosage; D009949:Orientation / Q000502:physiology*; D051381:Rats; D011919:Rats, Inbred Strains; D013997:Time Factors
chemical_list: D018691:Excitatory Amino Acid Antagonists; D016202:N-Methylaspartate