Best practices for fNIRS publications

Abstract

The application of functional near-infrared spectroscopy (fNIRS) in the neurosciences has been expanding over the last 40 years. Today, it is addressing a wide range of applications within different populations and utilizes a great variety of experimental paradigms. With the rapid growth and the diversification of research methods, some inconsistencies are appearing in the way in which methods are presented, which can make the interpretation and replication of studies unnecessarily challenging. The Society for Functional Near-Infrared Spectroscopy has thus been motivated to organize a representative (but not exhaustive) group of leaders in the field to build a consensus on the best practices for describing the methods utilized in fNIRS studies. Our paper has been designed to provide guidelines to help enhance the reliability, repeatability, and traceability of reported fNIRS studies and encourage best practices throughout the community. A checklist is provided to guide authors in the preparation of their manuscripts and to assist reviewers when evaluating fNIRS papers.

Keywords: functional near-infrared spectroscopy; guidelines; publication best practices.

Fig. 1

Experimental paradigm visualization. Sample legend follows. Schematic illustration of the n-back paradigm. Each experimental run consisted of 30 blocks with an interblock interval of 15 s. Each block has 15 trials and starts with the task instruction “n-back” displayed for 2 s on the screen. After the instruction, letters are displayed on the screen, one at a time, for 0.5 s. The intertrial interval is 1.5 s, during which a fixation cross is displayed on the screen. Participants were instructed to indicate whether the current letter is identical to the one presented “n” trials preceding it.

Fig. 2

Example of optode array set up with 12/14 source/detectors resulting in 34 channels over prefrontal cortex with 30-mm separation. Sensitivity profile in ${\log }_{10}({\mathrm{mm}}^{-1})$. Visualization using AtlasViewer.

Fig. 3

Overview of elemental fNIRS preprocessing steps. Light blue circular arrow indicates conventional processing order. It is worth noting note that, depending on the analysis, not all steps are always present or necessary.

Fig. 4

The likelihood of measuring real hemodynamic changes in the cerebral cortex is determined by the depth-sensitivity of the fNIRS measurements and the impact of confounding systemic physiological signals. Checklist for estimating the likelihood of obtaining cerebral signals (a), methodological factors that affect the likelihood of obtaining signals of cerebral origin (b).