The effects of cortical or hippocampal damage on behavioral flexibility in the rat

Abstract

Behavioral flexibility in neodecorticate, hippocampal, or control rats was assessed in an obstructed alleyway task. Rats were first trained to dislodge an obstructing ball from a tubular alleyway, either by pushing it into the goalbox or by pulling it into the startbox. At response transfer, the trained response was prevented and the rat had to develop the alternative response in order to clear the alleyway. A series of reversals between responses was then required. Neodecorticate rats were faster than sham-operated rats in transferring from pushing to pulling, but slower on the converse transfer; hippocampals were slower than controls only on transferring from pushing to pulling. All groups completed the reversals competently. Although the neo-decorticates demonstrated a unique behavioral profile, their results cannot be explained simply in terms of response bias. Rather, their behavior in the obstructed alleyway task provides evidence of residual flexibility, and it is quite different from that of the hippocampals.