Susceptibility to interference and intrusion errors in consequence of the dominant hemisphere's hippocampal infarct:...

We present a case of a man with an ischemic lesion of the left hippocampus. Detailed neuropsychological assessment revealed susceptibility to retroactive interference and a tendency to make intrusion errors in addition to mild deficits in the verbal memory processes. Although retroactive interference and intrusion errors are normally considered to be the manifestations of frontal lobe dysfunctions, the idea of susceptibility to interference has recently begun to emerge in the literature, as an explanation of medial temporal lobe amnesia. Our data support this new theory, suggesting that one role of the hippocampus is to decrease the interference during the learning processes.