title: The role of the hippocampus in passive and active spatial learning.
abstract: Rats with lesions of the hippocampus or sham lesions were required in four experiments to escape from a square swimming pool by finding a submerged platform. Experiments 1 and 2 commenced with passive training in which rats were repeatedly placed on the platform in one corner-the correct corner-of a pool with distinctive walls. A test trial then revealed a strong preference for the correct corner in the sham but not the hippocampal group. Subsequent active training of being required to swim to the platform resulted in both groups acquiring a preference for the correct corner in the two experiments. In Experiments 3 and 4, rats were required to solve a discrimination between different panels pasted to the walls of the pool, by swimming to the middle of a correct panel. Hippocampal lesions prevented a discrimination being formed between panels of different lengths (Experiment 3), but not between panels showing lines of different orientations (Experiment 4); rats with sham lesions mastered both problems. It is suggested that an intact hippocampus is necessary for the formation of stimulus-goal associations that permit successful passive spatial leaning. It is further suggested that an intact hippocampus is not necessary for the formation of stimulus-response associations, except when they involve information about length or distance.
authors.affiliation: School of Psychology, Cardiff University, United Kingdom.
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Kosaki
authors.forename: Tzu-Ching Esther
authors.initials: TC
authors.lastname: Lin
authors.forename: Murray R
authors.initials: MR
authors.lastname: Horne
authors.forename: John M
authors.initials: JM
authors.lastname: Pearce
authors.forename: Kerry E
authors.initials: KE
authors.lastname: Gilroy
mesh_terms: D000818:Animals; D001245:Association Learning / Q000502:physiology*; D004192:Discrimination, Psychological / Q000502:physiology*; D018690:Excitatory Amino Acid Agonists / Q000633:toxicity; D006040:Goals; D006624:Hippocampus / Q000187:drug effects / Q000502:physiology* / Q000503:physiopathology; D007051:Ibotenic Acid / Q000633:toxicity; D008297:Male; D009043:Motor Activity / Q000502:physiology; D009483:Neuropsychological Tests; D009949:Orientation; D051381:Rats; D065853:Spatial Learning / Q000502:physiology*; D013550:Swimming / Q000502:physiology
chemical_list: D018690:Excitatory Amino Acid Agonists; D007051:Ibotenic Acid
keywords: S-S versus S-R association; hippocampus; length discrimination; passive learning; spatial learning