A comparison of kainic acid plus colchicine and ibotenic acid-induced hippocampal formation damage on four configural tasks in rats.

J.W. Rudy and R.J. Sutherland (1989) suggested that the hippocampal formation (HF) is necessary for performance of configural tasks and that rats with kainic acid + colchicine (K-C) damage to the HF were impaired on the negative patterning problem (A+, B+, AB-). However, M. Gallagher and P.C. Holland (1992) found spared performance on a similar task (AC+, B+, AB-, C-) when ibotenic acid (IBO) was used. This study compared the effects of K-C- and IBO-induced HF damage on 4 configural tasks: (a) negative patterning, (b) the Gallagher-Holland task, (c) transverse patterning, and (d) place learning. Rats with IBO lesions performed like controls on the Gallagher-Holland task (replicating M. Gallagher & P.C. Holland) but were impaired on negative patterning, transverse patterning, and place learning. In contrast, rats with K-C lesions were impaired on all 4 tasks. The implications of these results for theories of HF function are discussed.