Task-Related Systemic Artifacts in Functional Near-Infrared Spectroscopy*

Functional near-infrared spectroscopy (fNIRS) has the potential to become the next common noninvasive neuroimaging technique for routine clinical use. Compared to the current standard for neuroimaging, functional magnetic resonance imaging (fMRI), fNIRS boasts several advantages which increase its likelihood for clinical adoption. However, fNIRS suffers from an intrinsic interference from the superficial tissues, which the near-infrared light must penetrate before reaching the deeper cerebral cortex. Therefore, the removal of signals captured by SS channels has been proposed to attenuate the systematic interference. This study aimed to investigate the task-related systemic artefacts, in a high-density montage covering the sensorimotor cortex. We compared the association between LS and SS channels over the contralateral motor cortex which was activated by a hand clenching task, with that over the ipsilateral cortex where no task-related activation was expected. Our findings provide important guidelines regarding how to removal SS signals in a high-density whole-head montage.