Near-infrared spectroscopy (NIRS) is a non-invasive neuroimaging method that usng low level lights (650–850nm light) allows to infer brain activity (Jöbsis, 1977; Wyatt et al., 1986; Chance et al., 1988). NIRS measures changes in oxygenated hemoglobin (oxy-Hb) and deoxygenated hemoglobin (deoxy-Hb) concentration in the brain (Arizono et al., 2016); these parameters combined indicate changes in the total hemoglobin concentration (tot-Hb) (Yücel, Aasted, Petkov, Borsook, Boas & Becerra, 2015). In order to record the above-mentioned parameters, participants wear a nice cap, similar to that used for EEG recordings (Figure 1).
Figure 1 Cap used in our NIRS system, kindly demonstrated by Federico, our PhD student and model.
Useful references on guidelines:
Arizono, N., Ohmura, Y., Yano, S., & Kondo, T. (2016). Functional Connectivity Analysis of NIRS Data under Rubber Hand Illusion to Find a Biomarker of Sense of Ownership. Neural plasticity, 2016.
Chance, B., Leigh, J. S., Miyake, H., Smith, D. S., Nioka, S., Greenfeld, R., ... & Young, M. (1988). Comparison of time-resolved and-unresolved measurements of deoxyhemoglobin in brain. Proceedings of the National Academy of Sciences, 85(14), 4971-4975.
Jobsis, F. F. (1977). Noninvasive, infrared monitoring of cerebral and myocardial oxygen sufficiency and circulatory parameters. Science, 198(4323), 1264-1267.
Wyatt, J. S., Delpy, D. T., Cope, M., Wray, S., & Reynolds, E. O. R. (1986). Quantification of cerebral oxygenation and haemodynamics in sick newborn infants by near infrared spectrophotometry. The Lancet, 328(8515), 1063-1066.
Yücel, M. A., Aasted, C. M., Petkov, M. P., Borsook, D., Boas, D. A., & Becerra, L. (2015). Specificity of hemodynamic brain responses to painful stimuli: a functional near-infrared spectroscopy study. Scientific reports, 5, 9469.