Is the Amygdala Crucial for Cross-Modal Association in Humans?

Bilateral lesions of certain mesial temporal lobe regions reportedly hinder the formation of mental associations from one sensory modality to another. In monkeys, the amygdala has been implicated as the crucial structure in the transfer of information across sensory modalities. Investigations into the role of the human amygdala in cross-modal association have produced contradictory results. This article explores these divergent findings and compares the cross-modal association performance of 2 bilateral amygdalotomy patients and 1 bitemporal patient with amnesia to that of 23 normal controls. There were no pre-to postoperative changes in the amygdalotomy patients and no statistically significant differences between controls and patients on any of the cross-modal tasks. Results suggest that formation of mental associations from one sensory modality to another in humans probably does not depend on the amygdala or the hippocampus.