fMRI-based validation of continuous-wave fNIRS of supplementary motor area activation during motor execution and motor imagery

Abstract

Compared to functional magnetic resonance imaging (fMRI), functional near infrared spectroscopy (fNIRS) has several advantages that make it particularly interesting for neurofeedback (NFB). A pre-requisite for NFB applications is that with fNIRS, signals from the brain region of interest can be measured. This study focused on the supplementary motor area (SMA). Healthy older participants (N = 16) completed separate continuous-wave (CW-) fNIRS and (f)MRI sessions. Data were collected for executed and imagined hand movements (motor imagery, MI), and for MI of whole body movements. Individual anatomical data were used to (i) define the regions of interest for fMRI analysis, to (ii) extract the fMRI BOLD response from the cortical regions corresponding to the fNIRS channels, and (iii) to select fNIRS channels. Concentration changes in oxygenated ($$\Delta [HbO]$$ Δ [ H b O ] ) and deoxygenated ($$\Delta [HbR]$$ Δ [ H b R ] ) hemoglobin were considered in the analyses. Results revealed subtle differences between the different MI tasks, indicating that for whole body MI movements as well as for MI of hand movements $$\Delta [HbR]$$ Δ [ H b R ] is the more specific signal. Selection of the fNIRS channel set based on individual anatomy did not improve the results. Overall, the study indicates that in terms of spatial specificity and task sensitivity SMA activation can be reliably measured with CW-fNIRS.

Performance comparison of systemic activity correction in functional near-infrared spectroscopy for methods with and without short distance channels

“…In addition, both semi-simulated and real data the quality measures changed for Δ[ HbR ] after correction, which confirms that Δ[ HbR ] is influenced by SA too and should thereby be corrected accordingly. 26…”

“…The real data set comprised ME and MI data. Details of the study design can be found in Klein et al 26 In short, N = 32 healthy elderly individuals performed five motor tasks, that is, a self-paced sequential finger tapping task that was physically performed with either the left (ME LEFT) or the right (ME RIGHT) hand or kinesthetically imagined with either the left or the right hand. The fifth task was the kinesthetic imagination of an arbitrarily chosen whole-body movement involving both arms and legs.…”

“…Therefore, EMG data were not considered in the present study. For details on how EMG data were collected an analysed see Klein et al 26…”

“…General inclusion criteria for both studies were right-handedness, no experience in piano playing, > 4 h of sleep and no history of neurological, psychiatric or psychological diseases (cf. Klein et al, 2022 26 for more details and all exclusion criteria). Both studies were approved by either the regular (resting-state data) or the medical (real data) Ethics Committee of the University of Oldenburg.…”

“…For both data sets, electromyography (EMG) data were recorded. In a previous study, 26 EMG data of MI DATA were used to control for voluntary movements during the MI tasks. However, in the present study we neglected possible movements during MI mainly because the focus was not to investigate MI induced brain activation but to explore and compare the performance of different correction methods.…”