Radial-arm-maze behavior by rats with dorsal hippocampal lesions: effect of cuing.

Rats with bilateral dorsal hippocampal lesions were impaired when tested on standard (non-cued) versions of the radial arm maze, but other hippocampal groups performed almost as well as cortical and operated control groups when salient visual cues were added to each arm. Preoperative training on the non-cued, but not the cued, maze interfered with the benefits of postoperatively cuing hippocampal groups. Control groups performed equally well under all cuing and training conditions. Procedures that eliminated response sequencing did not affect performance of hippocampal or control groups. The results were interpreted as reflecting hippocampal involvement in mediating spatial cues but not necessarily along the lines predicted by cognitive map theory. It is suggested that deficits animals with hippocampal lesions represent one manifestation of a general impairment in processing information.