Neural Noise- An fNIRS hyperscanning study examined the influence of team type and sex on athletes’ interpersonal trust and neural mechanisms (Nature).1
- Methods are relevant to fNIRS-based BCI; application is social and behavioral (tier-2).1 1
Weekly enrichment (2026-07-20)
- The primary study (Zhou et al., Scientific Reports 2025, DOI 10.1038/s41598-025-12565-8) recruited 48 athlete dyads split into a cooperative-competitive “cooperation” group (24 dyads from team sports such as basketball and soccer) and a competitive-cooperative “competition” group (24 dyads from individual sports such as athletics and tennis), each balanced with 12 male and 12 female dyads in a 2 (sex) × 2 (group) factorial design.2
- An a-priori G*Power 3.1 analysis (medium effect size d = 0.50, power 0.80, α = 0.05) indicated a required total sample of 34, so the 96-participant (48-dyad) sample was adequately powered.2
- Brain data were collected with a Hitachi ETG-7100 optical topography system at a 10 Hz sampling rate using 695 nm and 830 nm wavelengths; 8 emitters and 7 detectors spaced 3 cm apart formed 22 prefrontal channels centered on Fpz (10–20 system), with channel positions mapped to MNI space via NIRS-SPM.2
- Interpersonal neural synchronization was computed on oxygenated hemoglobin only, using wavelet transform coherence (WTC); task-related INS increases were significant in the 0.010–0.017 Hz band (60–100 s window) after FDR correction (p < 0.05), a range that covers the ~20 s decision window while avoiding cardiac (~0.7–4 Hz) and respiratory (0.2–0.3 Hz) noise.2
- Behaviorally, a two-way ANOVA found a significant group main effect on the investment rate (F = 22.77, p = 0.001, partial η² = 0.51) with the cooperation group investing more, while return rates and all sex and group×sex interaction effects were non-significant (p > 0.05).2
- Questionnaire trust scores showed a significant group main effect (F = 6.65, p = 0.013, η² = 0.13); post-hoc tests found the female cooperation-vs-competition difference only marginal (p = 0.057) and no significant male group difference (p = 0.119).2
- In the fNIRS data, female athletes in the cooperation group showed stronger left-frontal-lobe INS than female competition-group athletes during investment decisions, and within the competition group females showed stronger left dorsolateral prefrontal INS than males.2
- A permutation test (1,000 shuffles of non-interacting pseudo-dyads, p < 0.05) confirmed that the observed synchrony reflected genuine interaction rather than task-similarity artifacts, strengthening the INS claim.2
- Context: a 13-study, 890-participant meta-analysis of fNIRS hyperscanning of cooperation found statistically significant interbrain synchrony with large effect sizes in frontal and temporoparietal areas, with all 13 studies reporting PFC synchrony—consistent with the prefrontal locus reported here and relevant to social/affective fNIRS-BCI readouts (tier-2 application).3