Fig. 3.

Hippocampal lesions impair spatial learning and enhance cued learning. (A) Minimum and maximum hippocampal lesions at two rostro-caudal levels (adapted from ref. 46). (B) Hippocampal lesions impaired spatial learning, as assayed in probe trials after 3 and 5 days of training (n = 13 lesioned, spatial; n = 12 control, spatial; n = 15 lesioned, cued; n = 13 control, cued; see text for statistical analysis). (C) Hippocampal lesions enhanced cued learning. Lesioned animals showed significant learning on day 5, whereas controls showed only a trend goal bias that did not reach significance at this time point. (D) Similar effects in the cued task were seen in an alternate analysis, wherein probe trial data were analyzed by occupancy in circular zones (25 cm diameter) around goal and lure cues. See text for statistical analysis. All data are mean ± SEM; †, P < 0.1; *, P < 0.05; **, P < 0.01; ***, P < 0.005.