Effects of temporal neocortical excisions on musical processing

Abstract

Subjects who had undergone unilateral temporal-lobe excisions for the relief of epilepsy were tested in order to study the relation between musical processing and cerebral function. In one study it was found that only right temporal-lobe lesions including Heschl's gyri (the primary auditory cortex) resulted in a significant deficit in judging pitch changes when the fundamental of a complex tone was missing. In melodic discrimination tasks right-temporal lobectomy had a deleterious effect, but the excisions of Heschl's gyri from either side resulted in a more marked deficit. Other experiments involving identification of familiar distorted tunes and recognition of lyrics of songs primarily show effects of left temporal-lobe lesions. However, a case of absolute pitch ability showed no disturbance from a left temporal-lobe lesion. The results are discussed in terms of the possible contribution of different cortical regions to specific aspects of musical processing.

KEY WORDS:

• Temporal lobe
• Heschl's gyri
• pitch
• melody
• discrimination