Real-World fNIRS Brain Activity Measurements during Ashtanga Vinyasa Yoga.

Henrikke Dybvik,Martin Steinert

doi:10.3390/brainsci11060742

Abstract

Functional near-infrared spectroscopy (fNIRS) is often praised for its portability and robustness towards motion artifacts. While an increasing body of fNIRS research in real-world environments is emerging, most fNIRS studies are still conducted in laboratories, and do not incorporate larger movements performed by participants. This study extends fNIRS applications in real-world environments by conducting a single-subject observational study of a yoga practice with considerable movement (Ashtanga Vinyasa Yoga) in a participant’s natural environment (their apartment). The results show differences in cognitive load (prefrontal cortex activation) when comparing technically complex postures to relatively simple ones, but also some contrasts with surprisingly little difference. This study explores the boundaries of real-world cognitive load measurements, and contributes to the empirical knowledge base of using fNIRS in realistic settings. To the best of our knowledge, this is the first demonstration of fNIRS brain imaging recorded during any moving yoga practice. Future work with fNIRS should take advantage of this by accomplishing studies with considerable real-world movement.

Highlights

Functional near-infrared spectroscopy is a non-invasive, lightweight, and portable neuroimaging technique which measures cortical brain activity [1,2]. fNIRS uses optical fibers to emit near-infrared light into a region of the brain, and detect changes in blood flow oxygenation (oxygenated (∆HbO)) and deoxygenated hemoglobin (∆HbR), caused by neural activation [1]
This study explores the boundaries of cognitive load measurements in the real-world, and contributes to the empirical knowledge base of using fNIRS in realistic settings
This study obtained fNIRS brain activity measurements from seven (N = 7) sessions of an Ashtanga Vinyasa Yoga practice conducted in a real-world environment

Summary

Introduction

Functional near-infrared spectroscopy (fNIRS) is a non-invasive, lightweight, and portable neuroimaging technique which measures cortical brain activity [1,2]. fNIRS uses optical fibers to emit near-infrared light into a region of the brain, and detect changes in blood flow oxygenation (oxygenated (∆HbO)) and deoxygenated hemoglobin (∆HbR), caused by neural activation [1]. FNIRS uses optical fibers to emit near-infrared light into a region of the brain, and detect changes in blood flow oxygenation (oxygenated (∆HbO)) and deoxygenated hemoglobin (∆HbR), caused by neural activation [1]. Non-absorbed light scatter components are detected, and ∆HbO and ∆HbR are calculated by the modified Beer-Lambert Law. Neural activity induces changes in local hemodynamics, causing an increase in HbO concentration in the activated region, and a decreased concentration of HbR [1,2,3] ( this is not always the case [4]). Neural activity induces changes in local hemodynamics, causing an increase in HbO concentration in the activated region, and a decreased concentration of HbR [1,2,3] ( this is not always the case [4]) This is used to measure cognitive states and cognitive load [5,6,7,8].

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