Validation of a mobile fNIRS device for measuring working memory load in the prefrontal cortex

Area of Science:

• Neuroscience
• Cognitive Science
• Biomedical Engineering

Background:

• Functional near-infrared spectroscopy (fNIRS) is a neuroimaging method for assessing brain activity.
• Traditional fNIRS systems are often costly and lab-bound, limiting accessibility.
• Mobile fNIRS offers a portable and potentially more accessible alternative for neuroimaging research.

Purpose of the Study:

• To validate the Mendi, a two-channel mobile fNIRS system, for measuring prefrontal oxyhemoglobin concentration changes.
• To assess the Mendi's ability to differentiate between low and high cognitive loads using an n-back task.
• To evaluate the correlation between neuroimaging data and behavioral performance during cognitive tasks.

Main Methods:

• Utilized a two-channel mobile fNIRS system (Mendi) to record prefrontal oxyhemoglobin levels.
• Administered an n-back task with varying difficulty levels (one-back vs. three-back).
• Collected behavioral data on task accuracy to complement fNIRS measurements.

Main Results:

• Significantly increased prefrontal oxyhemoglobin concentrations were observed during the more demanding three-back task compared to the one-back task.
• The Mendi system demonstrated sensitivity to different cognitive task loads.
• Behavioral results showed decreased accuracy in the high cognitive load condition, aligning with fNIRS findings.

Conclusions:

• The Mendi mobile fNIRS system is a validated tool for assessing working memory load.
• Mobile fNIRS enhances the accessibility of neuroscientific research.
• This technology facilitates the study of neural processes in real-world settings across diverse populations.