Figure 2.

Memory formation for TDPA depends on hippocampus. Mice with hippocampal lesion (injected with ibotenic acid, n = 9) and sham-operated mice (injected with PBS, n = 10) were trained by TDPA as described in Figure 1. A, Lesioned mice displayed poor TDPA performance, as indicated by shorter crossover latency during testing. B, The percentage of animals reaching the cutoff value (300 s) was lower for lesioned mice. C, D, The hippocampal morphology was examined by cresyl violet staining. Hippocampal lesion occurred in ibotenic acid-injected (C) but not in PBS-injected mice (D). The boxed regions in the top panels were enlarged and shown in the bottom panels.