Sex differences in parietal lobe activation among orienteering athletes during a mental rotation task using functional near-infrared spectroscopy.

This study used fNIRS to examine sex differences in spatial cognition and brain function in orienteering athletes during mental rotation. Forty-two athletes performed a letter-based mental rotation task while fNIRS data were recorded. After quality control, 33 participants were included. Behavioral performance, brain activation, and brain-behavior relationships were analyzed using t-tests, correlations, and ANCOVA, with FDR correction for multiple comparisons. Males showed higher accuracy than females (83.33% vs. 69.68%, p = 0.039, d = 0.91), but reaction time did not differ (p = 0.228). No significant brain activation differences were found after FDR correction, though a marginal trend was observed in the IPL region for HbT (q = 0.074, d = -0.91), with males showing lower activation. Sex-specific correlations were found: BA5 HbR correlated with reaction time in females (r = 0.547), and IPL HbR correlated with reaction time in males (r = 0.458). Females showed greater inter-individual variability. Male behavioral advantages were directionally consistent with lower parietal activation, aligning with the neural efficiency hypothesis. Sex-specific relationships and greater female variability suggest strategic heterogeneity. This study provides preliminary fNIRS evidence for sex differences in mental rotation among orienteering athletes, with conclusions restricted to this population.