Dissociated verbal and nonverbal retrieval and learning following left anterior temporal damage.

A subject with circumscribed damage to mesial and nonmesial risk anterior temporal structures (which included the left entorhinal cortex and hippocampus and the left anterolateral association cortices) maintains accurate nonverbal records of past experiences, and acquires accurate new nonverbal records. However, he has a severe defect in the retrieval and acquisition of specific verbal tags denoting those records. This dissociation is revealed by standard neuropsychological tasks, and by experimental probes focused on (1) retrieval of previously learned verbal and nonverbal entities; and (2) acquisition of new visuoverbal relationships. The results extend our current understanding of the manner in which mesial and nonmesial structures in the anterior temporal lobe contribute to the formation and storage of verbal and nonverbal records.