Functional Magnetic Resonance Imaging and Functional Near-Infrared Spectroscopy: Insights from Combined Recording Studies

Abstract

Although blood oxygen level dependent (BOLD) functional magnetic resonance imaging (fMRI) is a widely available, non-invasive technique that offers excellent spatial resolution, it remains limited by practical constraints imposed by the scanner environment. More recently, functional near infrared spectroscopy (fNIRS) has emerged as an alternative hemodynamic-based approach that possesses a number of strengths where fMRI is limited, most notably in portability and higher tolerance for motion. To date, fNIRS has shown promise in its ability to shed light on the functioning of the human brain in populations and contexts previously inaccessible to fMRI. Notable contributions include infant neuroimaging studies and studies examining full-body behaviors, such as exercise. However, much like fMRI, fNIRS has technical constraints that have limited its application to clinical settings, including a lower spatial resolution and limited depth of recording. Thus, by combining fMRI and fNIRS in such a way that the two methods complement each other, a multimodal imaging approach may allow for more complex research paradigms than is feasible with either technique alone. In light of these issues, the purpose of the current review is to: (1) provide an overview of fMRI and fNIRS and their associated strengths and limitations; (2) review existing combined fMRI-fNIRS recording studies; and (3) discuss how their combined use in future research practices may aid in advancing modern investigations of human brain function.

The present and future use of functional near‐infrared spectroscopy (fNIRS) for cognitive neuroscience

“…Several studies [48][49][50][51][52] have been conducted to validate and to compare the metabolic correlates of neural activity as measured by fNIRS (i.e., increase in HbO 2 and decrease in HbR) with the gold standard measured by fMRI (i.e., the blood oxygenation level-dependent (BOLD) response). Positive correlations between the BOLD signal and HbO 2 were found as well as anticorrelations with HbR.…”

Investigation of brain functional connectivity in patients with mild cognitive impairment: A functional near‐infrared spectroscopy (fNIRS) study

“…Although fMRI can scan the whole brain with a high spatial resolution, it cannot be used on patients with a metal‐implanted device, and it is expensive to monitor brain functional connectivity longitudinally. On the other hand, fNIRS is relatively low‐cost, and it can be applied to the populations previously inaccessible to fMRI . Additionally, whereas fMRI is sensitive to the concentration change of the deoxygenated form of hemoglobin (deoxyhemoglobin), fNIRS can measure signals of both oxyhemoglobin (HbO) and deoxyhemoglobin (Hb) .…”

Altered Functional Connectivity in the Motor and Prefrontal Cortex for Children With Down's Syndrome: An fNIRS Study

“…Differently from EEG, both fMRI and fNIRS are based on the detection of changes in regional cerebral blood flow or blood oxygen to infer brain activity. Compared to fMRI, fNIRS has the advantages of being a portable and comfortable technique for children development studies, in which brain imaging can be performed in a quiet environment with fewer body constraints (Cheng et al, 2015;Liu et al, 2016;Scarapicchia et al, 2017).…”