Parietal Structural and Functional Differentiation Associated with Visual Tracking Across Motor Participation...

This study aimed to examine whether structural and resting-state functional measures of parietal subregions differ across predefined motor participation groups with comparable physical activity levels, and whether these neural measures are associated with visual tracking performance.

We adopted an a priori motor-cognitive grouping framework and recruited athletes accordingly, using two representative sports as operational exemplars for each profile: (1) externally driven spatial updating and action planning (ESU; basketball and taekwondo), (2) body-environment calibration and rhythmic sensorimotor integration (SCP; skating and running), and 3) internally guided control and sustained attentional precision (IPS; tai chi and shooting). A sedentary control group (CON) with low habitual physical activity was also recruited. In total, 80 college students participated. Physical activity (PA) was assessed using a standardized questionnaire. All participants underwent structural MRI and resting-state fMRI to derive gray matter volume (GMV), fractional amplitude of low-frequency fluctuations (fALFF), degree centrality (DC), regional homogeneity (ReHo), and functional connectivity (FC) within parietal subregions (S1, SPL, AG, and SMG). Supplementary SPL-based FC analyses further examined connectivity with regions of the broader visuospatial and sensorimotor network. Visual tracking was assessed using a multiple object tracking (MOT) task across three difficulty levels.

PA levels were significantly higher in all athlete groups than in sedentary controls, with no differences among athlete groups. Across structural and resting-state functional measures, the most consistent group differences were selectively concentrated in S1 and SPL, whereas effects involving other parietal regions were less consistent across measures. Specifically, the ESU group exhibited the highest bilateral S1 GMV, the SCP group showed the highest bilateral SPL GMV, and the IPS group demonstrated the highest fALFF in both S1 and SPL. The IPS group also showed the highest ReHo in bilateral SPL. FC differed significantly across several parietal connections, with distinct connectivity patterns across the three athlete groups. MOT accuracy differed significantly across groups at all difficulty levels, with the ESU and IPS groups outperforming the SCP and CON groups overall. Across all participants, multiple S1 and SPL metrics showed modest associations with MOT performance (r = 0.20-0.40). Within athlete subgroups, stronger and task-specific associations were observed, particularly in the SCP and IPS groups (r = 0.50-0.80).

These findings identify distinct structural and functional patterns predominantly involving S1 and SPL across different motor participation profiles, despite comparable overall physical activity levels among the athlete groups. Such parietal differences are accompanied by difficulty-dependent differences in visual tracking performance and heterogeneous brain-behavior associations. Together, the results highlight S1 and SPL as the parietal regions showing the most consistent differentiation across structural and functional measures in association with distinct motor participation profiles and visual tracking performance, and provide a focused empirical basis for future investigations into the sources of this heterogeneity.