overview
Started as a research project during my overseas study at National Cheng Kung University (NCKU), Taiwan, during July, 2024 to November, 2024, this study explored brain activation during upper-extremity force regulation at everyday-relevant force levels (4, 12, 20 N), under static and dynamic tasks. Eighteen healthy adults performed the tasks while fNIRS recorded HbO/HbR over PFC, PMC, SMA, and M1.
Methods
- Participants: 18 young adults (5 male, 13 female; mean 22.33 ± 1.80 y)
- Experiment & conditions: 3 difficulty levels (Easy 4 N / Moderate 12 N/ Hard 20 N ) and 2 movements (static, dynamic)
- Robotic arm as force regulator: UR3e regulated force and guided motion
- fNIRS: NIRx NIRScout (8 LED sources and 16 detectors, 30 channels at 760/850 nm; 7.81 Hz) over PFC, PMC, SMA, M1 according to EEG1010 montage.
- Processing: Homer3 pipeline and AtlasViewer for topomaps.
- Statistical Analysis: Two-way repeated-measures ANOVA (Task difficulty × Movement) with ART where non-normal with Bonferroni correction, and hemisphere tests (c vs i).
Key Results
- No interaction between difficulty and movement in any ROI.
- Difficulty main effects: cM1, cPMC, iPMC, and iPFC show significant HbO increases with higher force demand; pairwise effects strongest easy to hard.
- Movement main effect: PFC only; static > dynamic in both hemispheres.
- Hemisphere effects: M1 shows contralateral have higher activity than ipsilateral; PFC shows ipsilateral less negative than contralateral.