White Matter Myelin Changes Related to Long-term Intensive Training in Japanese World-class Gymnasts

Objective: To explore the myelin changes induced by long-term intensive training in Japanese World Class Gymnasts (J-WCGs) using a myelin-sensitive imaging technique known as magnetization transfer saturation (MTsat) imaging and tract-based spatial statistics (TBSS) analysis. Materials: Ten right-handed J-WCGs and 10 age- and sex-matched right-handed non-athlete healthy controls were included. Methods: All imaging data were obtained using a 3-T scanner (MAGNETOM Prisma, Siemens Healthcare, Erlangen, Germany) equipped with a 64-channel head coil. Diffusion tensor imaging (fractional anisotropy [FA]) and MTsat imaging (myelin volume fraction [MVF]) parameters were compared between J-WCGs and controls using TBSS analysis. In addition, white matter volume (WMV) and white matter fraction volume (WMV/intracranial volume) were also compared between the two groups. Results: MVF in some white matter areas, including the inferior fronto-occipital fasciculus and inferior and superior longitudinal fasciculi in J-WCGs, was significantly lower than those of the controls. However, FA was only significantly lower in the genu and splenium of corpus callosum. No significant differences were demonstrated in WMV and WMF between groups. Conclusions: Our results indicate that long-term intensive gymnastic training could induce myelin changes in the white matter related to visuomotor processing and attention control. Further, gymnastic practice may cause myelin neuroplasticity in the white matter.