Motor cortex and hand motor skills: structural compliance in the human brain.
Level 4 - case-series / case-control
Cross-sectional case-control study
PubMed 20408216 · doi:10.1002/(SICI)1097-0193(1997)5:3<206::AID-HBM5>3.0.CO;2-7
What was done
Right-handed professional keyboard players were compared to an age- and handedness-matched control group using magnetic resonance imaging. Investigators measured the intrasulcal length of the precentral gyrus (ILPG) along the posterior wall bordering the central sulcus in horizontal slices of both hemispheres as a proxy for primary motor cortex size. Hemispheric asymmetry and the correlation between ILPG size and the starting age of musical training were evaluated.
What was found
The abstract reports no numerical values, sample sizes, or p-values. Directionally, controls showed a pronounced left-larger-than-right asymmetry in ILPG, whereas keyboard players showed more symmetrical ILPG measurements. Differences were most pronounced in the dorsal region corresponding to the presumed hand representation, especially in the nondominant right hemisphere. Among keyboard players, ILPG size was negatively correlated with the age at which musical training commenced.
Why it matters
This study provides structural neuroimaging evidence that intensive, prolonged bimanual motor skill acquisition is associated with macroscopic morphological adaptations in the human motor cortex, particularly when training begins earlier in life.
Limits
The abstract reports no sample sizes, effect sizes, or exact statistics. The cross-sectional design cannot establish causality or exclude innate anatomical predispositions for musical proficiency. Furthermore, ILPG is an indirect structural proxy rather than a direct functional or histological measurement of the primary motor cortex.