Does post-operative environment attenuate or exacerbate symptoms which follow hippocampal lesions in rats?

Rats with dorsal hippocampal lesions (L) and control rats were tested pre- and post-operatively, on a spontaneous alternation task. Four days after surgery, the L group alternated significantly less than the control group. Starting on the fifth post-operative day, all rats were placed for either 7, 15 or 23 days in one of three different environments: enriched, social or impoverished. Environmental enrichment increased significantly spontaneous alternation in L rats, even for the shortest enrichment period. Although this result might be task and lesion specific, it clearly indicates that post-operative environmental enrichment can help to reduce post-operative symptoms in brain-damaged animals.