Behavioural Brain Research, 7 (1983) 133-153 133 Elsevier Biomedical Press Research Papers A BEHAVIOURAL ANALYSIS OF SPATIAL LOCALIZATION FOLLOWING ELECTROLYTIC, KAINATE- OR COLCHICINE-INDUCED DAMAGE TO THE HIPPOCAMPAL FORMATION IN THE RAT* R.J. SUTHERLAND, I.Q. WHISHAW and B. KOLB Department of Psychology, The University of Lethbridge, Lethbridge, Alberta T1K 3M4 (Canada) (Received May 12th, 1982) (Revised version received August 25th, 1982) (Accepted September 16th, 1982) Key words." hippocampus - spatial learning - kainic acid - colchicine - dentate gyrus - rat SUMMARY This experiment examines the notion that in the rat the hippocampal formation is an essential structure in the neurological representation of spatial abilities. Spatial localization by rats with different types of hippocampal damage, including bilateral electrolytic lesions, unilateral and bilateral kainic acid-induced CA3-CA4 lesions, and unilateral and bilateral colchicine-induced dentate gyrus lesions, was compared with vehicle-injected and normal control groups in the Morris water task. The task required the rats to escape from cold water by finding a submerged and hidden platform located at a fixed place within the room. The start point was varied randomly from trial to trial and there were no local cues available to indicate the position of the hidden platform. After training, the platform was moved. Escape latencies and the initial swimming headings revealed that all lesion groups, except the unilateral CA3-damaged group, were impaired at finding the platform: the dentate-damaged rats exhibited the greatest deficit. When the platform was moved the control rats swam mainly in the part of the pool that had previously contained the platform and, on finding it in the new location, they showed a marked dishabituation of rearing. None of the bilateral lesion groups showed these effects. * The data in this paper formed part of a poster presentation at the 10th Annual Meeting of the Society for Neurosciences [27]. 0166-4328/83/0000-0000/$03.00 © 1983 Elsevier Biomedical Press