Poster E49, Thursday, August 22, 2019, 3:45 – 5:30 pm, Restaurant Hall
Left-handed musicians show a higher probability of atypical cerebral dominance for language: Overlap in the structural correlates of musicianship and lateralization
Esteban Villar-Rodríguez1, Jesús Adrián-Ventura1, María Ángeles Palomar-García1, Mireia Hernández2, Gustau Olcina-Sempere1, Maria Antonia Parcet1, Cesar Avila1;1Universitat Jaume I, 2University of Barcelona
Atypical language lateralization in the right hemisphere has been previously related to a more gyrified left Heschl’s gyrus and a gray matter rightward asymmetry of the right pars triangularis. In parallel, when comparing musicians to non-musicians, musicians present a higher gyrification of both Heschl’s gyri and a thicker right pars triangularis. Taking this into account, we wondered if musicianship was associated to atypical dominance for language and the brain correlates of atypical lateralization. METHODS: A healthy sample of 49 participants were included in this study (33 male; mean age ± SD = 20.7 ± 2.2). All participants were left-handed, according to the Edinburgh Handedness Inventory. 30 participants were musicians, requiring official music school formation and at least 9 years of instrumental experience. 19 participants were non-musicians, having no musical training beyond basic school education. 3D T1-weighted MPRAGE and T2*-weighted EPI sequences were acquired on a 3T Philips Achieva scanner. Two groups were formed according to fMRI assessment of language lateralization via Laterality Index calculation (Brodmann areas 9, 44, 45 and 46) on SPM12: left-lateralized (n=36, 12 musicians) and right-lateralized (n=12, 11 musicians). Differential incidence of atypical language lateralization between musicians and non-musicians was tested using Fisher’s exact test. Surface-based morphometry preprocessing and region of interest (ROI) analyses were carried out using the CAT12 toolbox for SPM12 following the default procedure described in the CAT12 manual. We used the HCP-MMP1 surface atlas to define a right pars triangularis ROI (right IFSa) and 3 left Heschl’s gyrus ROIs (left A1, LBelt and MBelt). Finally, we tested via one-tailed two-sample t tests if right-lateralized participants presented greater cortical thickness in the right pars triangularis ROI and greater gyrification index in any of the left Heschl’s gyrus ROIs. Age and musician/non-musician were included as covariates of no interest. All surface tests were corrected by multiple comparisons using an FDR threshold of p < 0.05. RESULTS: Atypical patterns (right and bilateral) of language processing were significantly more prevalent (p = 0.008) in musicians (40%) than in non-musicians (5.3%). When compared to the left-lateralized group, the right-lateralized group presented a thicker cortex in the right IFSa area (p = 0.021) and a higher gyrification index in the LBelt area (p < 0.017). CONCLUSIONS: In consonance with our hypotheses, musicianship is related to a higher incidence of atypical lateralization of language, and the brain correlates found in right-lateralized participants notably overlap with correlates described in the brain of musicians. In fact, recent findings have pinpointed a positive correlation between cortical thickness and pitch discrimination proficiency in the same portion of the right pars triangularis tested in our study, which further supports our view. Therefore, we propose that musicianship and atypical language lateralization are linked in the brain of left-handers, and we suggest the differential development of the right auditory-motor network as a potential structural basis for this relation.
Themes: Language Production, Development
Method: Functional Imaging