###### Abstract  
Cross-sectional studies suggest that motor skill learning is associated with working memory (WM) and white matter integrity (WMI). However, it has not been established whether motor skill learning improves WM performance, and information on its neural mechanisms have not been clearly elucidated. Therefore, this study compared WM and WMI across time points prior to and following football juggling learning, in early adulthood (18-20 years old), relative to a control group Study participants in the experimental group were subjected to football juggling for 10 weeks while participants in the control category went on with their routine life activities for the same period of time and were not involved in the learning-related activities. Data on cognitive measurements and that from diffusion tensor imaging (DTI) were collected before and after learning. There was a significant improvement in WM performance of the experimental group after motor learning, although no improvement was observed in the control group. Additionally, after learning, DTI data revealed a significant increase in functional anisotropy (FA) in the genu of corpus callosum (GOCC) and the right anterior corona radiata (R.ACR) in the experimental group. Moreover, the better WM associated with football juggling learning was correlated to a higher FA. Mediation analysis suggested that FA in the GOCC acts as a mediation variable between football juggling learning and WM. These findings show that motor skill learning improves the WM and remodels WMI in early adulthood. With a particular emphasis on the importance of WMI in motor skill learning and WM, this study also revealed the possible neural mechanisms mediated by WMI. motor learning: football juggling; working memory; diffusion tensor imaging; fractional anisotropy +
Footnote †: journal:  
Additionally, studies involving participants' various age groups has demonstrated that motor learning has a strong positive impact on WM behavioral indicators [8; 9; 10; 11; 12]. Moreover, surveys involving tennis and soccer players, walkers, and musicians showed that people trained for long had better working memory performance than non-professional controls, and performance of the working memory was correlated with the level of motor skills [13; 14; 15; 16; 17; 18]. However, current studies only focused on behavioral changes in WM, and the underlying mechanisms through which skill learning improves WM have not been clarified. Furthermore, advances in magnetic resonance imaging (MRI) and other technologies have facilitated studies on the relationship between working memory and brain structure at the neural level. For instance, [PERSON] et al. showed activated right dorsolateral prefrontal cortex and bilateral inferior parietal lobules through working memory tasks, while [PERSON] investigated the role of white matter structures in WM [2; 19]. Recent studies have reported that WM is closely correlated with brain structure, including the prefrontal cortex, basal ganglia, and thalamus [20; 21]. These studies do not establish whether motor skill learning plays a crucial role in cognitive behavior or in brain structure. Numerous studies have demonstrated that motor skill learning and acquisition can cause changes in brain structure [22; 23; 24; 25; 26; 27]. The brains of musicians, professional athletes, and others who have been trained for a long time have a different structure compared to those of non-professionals or novices [28]. Compared to non-musicians, musicians with long-term (more than 10 years) musical training were found to have a lower fractional anisotropy (FA) in their corona radiata and internal capsule, but higher FA in the genu of the corpus callosum [29]. World-class gymnasts were found to have lower FA in four regional deep white matter tracts when compared to non-athlete normal controls [28]. A number of longitudinal studies have also shown the effects of different types of skill training on white matter integrity (WMI). For example, [PERSON] et al.