Brain structures differ between musicians and non-musicians

Abstract

From an early age, musicians learn complex motor and auditory skills (e.g., the translation of visually perceived musical symbols into motor commands with simultaneous auditory monitoring of output), which they practice extensively from childhood throughout their entire careers. Using a voxel-by-voxel morphometric technique, we found gray matter volume differences in motor, auditory, and visual-spatial brain regions when comparing professional musicians (keyboard players) with a matched group of amateur musicians and non-musicians. Although some of these multiregional differences could be attributable to innate predisposition, we believe they may represent structural adaptations in response to long-term skill acquisition and the repetitive rehearsal of those skills. This hypothesis is supported by the strong association we found between structural differences, musician status, and practice intensity, as well as the wealth of supporting animal data showing structural changes in response to long-term motor training. However, only future experiments can determine the relative contribution of predisposition and practice.

Figure 1.

Brain regions with gray matter differences between professional musicians, amateur musicians, and non-musicians. The musician status was modeled as a three-level gradation in which professional musicians were ranked highest, amateur musicians were intermediate, and non-musicians were ranked lowest (see Materials and Methods for details). Only those voxels with a significant positive correlation between musician status and increase in gray matter volume are shown (p < 0.05; corrected for multiple comparisons). Only clusters of voxels consisting of at least 225 voxels are displayed, corresponding to a spatial extent threshold of p < 0.1. These clusters were overlaid on the rendered cortex surface of a selected single subject. Yellow lines indicate selected cuts through this brain, and the corresponding axial slices are shown in the left and right panels. These axial slices show the overlay of the results onto the average of all 80 single anatomical images.

Figure 2.

Relative differences in gray matter volume (mean and SD) between professional musicians, amateur musicians, and non-musicians in three selected regions. Regional differences in the left precentral gyrus (PrecG L), left Heschl's gyrus (HG L), and right superior parietal cortex (SPC R) using a spherical region of interest with a radius of 8 mm centered at the local maximal difference are shown.

Figure 3.

Location of cerebellar gray matter effects. The significant gray matter differences in the cerebellum in a selected coronal and axial section are shown. Orientation of these sections has been performed according to the coordinating system described by Grodd et al. (2001). The cluster in the cerebellar region corresponds to the area of the cerebellar finger-hand representation, as shown in functional imaging studies, and is located in the lobes HV/HVI according to the classification of Larsell and Jansen (1971).

Figure 4.

Overlap between different types of statistical analyses. This figure shows the results of the direct comparison between professional musicians and non-musicians (green) and the correlation with musician status (red) using the same statistical thresholds as in Figure 1. The overlap between both results is shown in yellow (as a result of mixing red and green). Results are displayed as maximum intensity projections (“glass brain”), which show highest values within each orientation.