Surgical Removal of the Right Arcuate Fasciculus Does Not Impair Music and Affective Prosody: a Single Case Study

Abstract The right hemisphere of the human brain plays an important role in music processing with lateralized functions for pitch, meter and melody recognition among other features. However, the relationship between white matter structure and function in music processing is relatively little explored. We report an interesting case study of a 50-year-old musician with a massive brain tumor affecting the frontal and parietal lobes (WHO grade III). The surgical resection of this high-grade lesion irreversibly damaged great portions of the right frontal and parietal lobes, as well as insula. Post-surgical diffusion tensor imaging (DTI) in vivo revealed that the right frontal aslant tract and the ventral pathway bundles of the patient preserved their integrity, whereas the right dorsal pathway (arcuate fasciculus) was removed completely. A comprehensive neuropsychological evaluation assessing language and affective prosody, executive functions, musical processing and emotion recognition in music revealed that the patient did not present language, prosody or cognitive deficits after the tumor removal, with the only exception of a selective impairment in recognizing emotion of fear in prosody. Moreover, the patient showed virtually intact musical processing. There were no signs of amusia, and the patient did not report any significant problems with his musical activities or music-related emotional processing. The only subjective report concerned the rhythmical abilities. This case study suggests that the right dorsal stream does not subserve musical and affective prosody processing, in this way adding new evidence to the ongoing debate of the white matter correlates of these cognitive functions.