The characteristics of cerebral cortical oxygenation levels and functional connectivity under upper and lower limb exercise-induced fatigue

Fig. 1. Experimental setup diagram. (A) shows upper limb exercise induced fatigue, and (B) shows lower limb exercise induced fatigue.

Fig. 2. The fNIRS monitored areas. (A) shows schematic diagram of fNIRS monitoring probes and channel distribution. Red circles represent light sources, blue circles represent detectors, and the lines represent channels. (B) The different colors in the figure represent different brain regions of interest.

Fig. 3. Changes in oxygenation levels before and after exercise-induced fatigue. (A) displays the differences in oxygenation levels before and after upper limb fatigue. (B) shows the differences in oxygenation levels before and after lower limb fatigue. The color bar represents the t-values of the differences, with larger t-values indicating greater differences. Red indicates oxygenation levels were higher before fatigue, while blue indicates oxygenation levels were lower before fatigue.

Fig. 4. Interbrain correlation matrix before and after upper limb exercise-induced fatigue. (A) shows the correlation matrix before upper limb motor fatigue, and (B) shows the correlation matrix after upper limb motor fatigue, the redder the color, the stronger the correlation, and the bluer the color, the weaker the correlation. (C) t ​> ​0 is shown in red, indicating before fatigue ​> ​after fatigue; t ​< ​0 is shown in blue, indicating before fatigue ​< ​after fatigue. (D)significant differences that pass FDR correction are shown in blue. LM1: Left Primary Motor Cortex; RM1: Right Primary Motor Cortex; LPM: Left Premotor and Supplementary Motor Cortex; RPM: Right Premotor and Supplementary Motor Cortex; LS1: Left Primary Somatosensory Cortex; RS1: Right Primary Somatosensory Cortex; LDLPFC: Left Dorsolateral Prefrontal Cortex; RDLPFC: Right Dorsolateral Prefrontal Cortex; LVLPFC: Left Ventrolateral Prefrontal Cortex; RVLPFC: Right Ventrolateral Prefrontal Cortex; LFPA: Left Frontal Pole Area; RFPA: Right Frontal Pole Area; LOFA: Left Orbitofrontal Area; ROFA: Right Orbitofrontal Area.

Fig. 5. Interbrain correlation matrix before and after lower limb exercise-induced fatigue. (A) shows the correlation matrix before lower limb motor fatigue, and (B) shows the correlation matrix after lower limb motor fatigue, the redder the color, the stronger the correlation, and the bluer the color, the weaker the correlation. (C) t ​> ​0 is shown in red, indicating before fatigue ​> ​after fatigue; t ​< ​0 is shown in blue, indicating before fatigue ​< ​after fatigue. (D) significant differences (p ​< ​0.05) are shown in blue, but they did not pass FDR correction. LM1: Left Primary Motor Cortex; RM1: Right Primary Motor Cortex; LPM: Left Premotor and Supplementary Motor Cortex; RPM: Right Premotor and Supplementary Motor Cortex; LS1: Left Primary Somatosensory Cortex; RS1: Right Primary Somatosensory Cortex; LDLPFC: Left Dorsolateral Prefrontal Cortex; RDLPFC: Right Dorsolateral Prefrontal Cortex; LVLPFC: Left Ventrolateral Prefrontal Cortex; RVLPFC: Right Ventrolateral Prefrontal Cortex; LFPA: Left Frontal Pole Area; RFPA: Right Frontal Pole Area; LOFA: Left Orbitofrontal Area; ROFA: Right Orbitofrontal Area.