Are left fronto-temporal brain areas a prerequisite for normal music-syntactic processing?

An increasing number of neuroimaging studies in music cognition research suggest that “language areas” are involved in the processing of musical syntax, but none of these studies clarified whether these areas are a prerequisite for normal syntax processing in music. The present electrophysiological experiment tested whether patients with lesions in Broca’s area (N=6) or in the left anterior temporal lobe (N=7) exhibit deficits in the processing of structure in music compared to matched healthy controls (N=13). A chord sequence paradigm was applied, and the amplitude and scalp topography of the Early Right Anterior Negativity (ERAN) was examined, an electrophysiological marker of musical syntax processing that correlates with activity in Broca’s area and its right hemisphere homotope. Left inferior frontal gyrus (IFG) (but not anterior superior temporal gyrus – aSTG) patients with lesions older than 4 years showed an ERAN with abnormal scalp distribution, and subtle behavioural deficits in detecting music-syntactic irregularities. In one IFG patient tested 7 months post-stroke, the ERAN was extinguished and the behavioural performance remained at chance level. These combined results suggest that the left IFG, known to be crucial for syntax processing in language, plays also a functional role in the processing of musical syntax. Hence, the present findings are consistent with the notion that Broca’s area supports the processing of syntax in a rather domain-general way.