Structural neuroplasticity in the sensorimotor network of professional female ballet dancers

Abstract

Evidence suggests that motor, sensory, and cognitive training modulates brain structures involved in a specific practice. Functional neuroimaging revealed key brain structures involved in dancing such as the putamen and the premotor cortex. Intensive ballet dance training was expected to modulate the structures of the sensorimotor network, for example, the putamen, premotor cortex, supplementary motor area (SMA), and the corticospinal tracts. We investigated gray (GM) and white matter (WM) volumes, fractional anisotropy (FA), and mean diffusivity (MD) using magnetic resonance-based morphometry and diffusion tensor imaging in 10 professional female ballet dancers compared with 10 nondancers. In dancers compared with nondancers, decreased GM volumes were observed in the left premotor cortex, SMA, putamen, and superior frontal gyrus, and decreased WM volumes in both corticospinal tracts, both internal capsules, corpus callosum, and left anterior cingulum. FA was lower in the WM underlying the dancers' left and right premotor cortex. There were no significant differences in MD between the groups. Age of dance commencement was negatively correlated with GM and WM volume in the right premotor cortex and internal capsule, respectively, and positively correlated with WM volume in the left precentral gyrus and corpus callosum. Results were not influenced by the significantly lower body mass index of the dancers. The present findings complement the results of functional imaging studies in experts that revealed reduced neural activity in skilled compared with nonskilled subjects. Reductions in brain activity are accompanied by local decreases in GM and WM volumes and decreased FA.

Figure 1

Local structural brain differences between professional female ballet dancers and control females. Decreased gray matter (GM) volume in ballet dancers are shown in red, decreased white matter (WM) volume in blue, and decreased fractional anisotropy (FA) in green. Statistical parametric maps were height‐thresholded with P = 0.001 (uncorrected) and cluster extent familywise error (FWE) corrected with P = 0.01. Additionally, clusters were corrected for nonstationarity of smoothness. Note that the size of the spots in Figure 1 deviates from the cluster size reported in Table II. This difference results from the nonstationary smoothness correction that is only implemented for the number (list) of clusters yet. The correction of the statistical image, that is, the maximum intensity projection itself, is not still possible due to technical problems in its implementation; hence the uncorrected cluster sizes are shown in the figure. L, left; R, right; x,y, x‐ and y‐coordinate in Montreal Neurological Institute (MNI) space.