# Neuroanatomical correlates of musicianship in left-handers

## TL;DR

Left-handed musicians have unique brain structures that may explain their higher prevalence and better musical skills.

## Contribution

The study identifies neuroanatomical correlates of musicianship specific to left-handers.

## Key findings

- Left-handed musicians have larger gray matter volume in both Heschl’s gyri compared to non-musicians.
- Left-handed musicians show more streamlines in the right arcuate fasciculus anterior segment.
- Atypical speech lateralization in left-handers correlates with rightward asymmetry in the arcuate fasciculus.

## Abstract

Left-handedness is a condition that reverses the typical left cerebral dominance of motor control to an atypical right dominance. The impact of this distinct control — and its associated neuroanatomical peculiarities — on other cognitive functions such as music processing or playing a musical instrument remains unexplored. Previous studies in right-handed population have linked musicianship to a larger volume in the (right) auditory cortex and a larger volume in the (right) arcuate fasciculus.

In our study, we reveal that left-handed musicians (n = 55), in comparison to left-handed non-musicians (n = 75), exhibit a larger gray matter volume in both the left and right Heschl’s gyrus, critical for auditory processing. They also present a higher number of streamlines across the anterior segment of the right arcuate fasciculus. Importantly, atypical hemispheric lateralization of speech (notably prevalent among left-handers) was associated to a rightward asymmetry of the AF, in contrast to the leftward asymmetry exhibited by the typically lateralized.

These findings suggest that left-handed musicians share similar neuroanatomical characteristics with their right-handed counterparts. However, atypical lateralization of speech might potentiate the right audiomotor pathway, which has been associated with musicianship and better musical skills. This may help explain why musicians are more prevalent among left-handers and shed light on their cognitive advantages.

The online version contains supplementary material available at 10.1186/s12993-024-00243-0.