fNIRS exhibits weak tuning to hand movement direction

Area of Science:

• Neuroscience
• Biomedical Engineering
• Signal Processing

Background:

• Functional near-infrared spectroscopy (fNIRS) is a portable tool for brain function research.
• Brain-machine interfaces (BMIs) often rely on decoding movement kinematics.
• Hemodynamic responses to hand movements are known, but decoding with fNIRS is under-explored.

Purpose of the Study:

• To investigate if fNIRS can decode hand movement direction from brain activity.
• To assess the accuracy of fNIRS in a brain-machine interface context.
• To evaluate fNIRS's potential for motor experiment research.

Main Methods:

• Recorded brain activity using fNIRS during two-directional hand movements.
• Analyzed hemodynamic signals in contralateral sensorimotor areas.
• Used a head tracking system for simultaneous recording.

Main Results:

• Hemodynamic signals showed weak variation with movement direction.
• Movement direction was decoded with ~65% accuracy on a single-trial basis.
• Decoding accuracy temporal evolution matched typical hemodynamic responses.
• Head movements did not significantly impact fNIRS signal decoding.

Conclusions:

• fNIRS shows limited accuracy for decoding movement direction, deeming it not viable for current BMIs.
• fNIRS's resistance to head movements makes it promising for motor experiment research.