Abstract
BACKGROUND: Direct electrical stimulation applied to the human medial temporal lobe (MTL) typically disrupts performance on memory tasks, however, the mechanism underlying this effect is not known. OBJECTIVE: To study the effects of MTL stimulation on memory performance. METHODS: We studied the effects of MTL stimulation on memory in five patients undergoing invasive electrocorticographic monitoring during various phases of a memory task (encoding, distractor, recall). RESULTS: We found that MTL stimulation disrupted memory performance in a timing-dependent manner; we observed greater forgetting when applying stimulation during the delay between encoding and recall, compared to when it was applied during encoding or recall. CONCLUSIONS: The results suggest that recall is most dependent on the MTL between learning and retrieval.