Verbal learning dysfunction with combined centre median and amygdala lesions.

Stereotaxic lesions in either or both amygdala did not impair verbal learning ability (presented by ear as a paired-associates test). Centre median lesions alone did not impair this form of learning; however, when combined with a left amygdala lesion a significant decrease in scores occurred which persisted for up to two years after operation. The data support a hypothesis that medial thalamic structures have alerting functions in learning mechanisms.