Conducting Concurrent Electroencephalography and Functional Near-Infrared Spectroscopy Recordings with a Flanker Task

Summary

The present protocol describes how to perform concurrent EEG and fNIRS recordings and how to inspect the relationship between the EEG and fNIRS data. 

Abstract

Concurrent EEG and fNIRS recordings offer an excellent opportunity to gain a full understanding of the neural mechanism of cognitive processing by inspecting the relationship between the neural and hemodynamic signals. EEG is an electrophysiological technology that can measure the rapid neuronal activity of the cortex, whereas fNIRS relies on the hemodynamic responses to infer brain activation. The combination of EEG and fNIRS neuroimaging techniques can identify more features and reveal more information associated with the functioning of the brain. In this protocol, fused EEG-fNIRS measurements were performed for concurrent recordings of evoked-electrical potentials and hemodynamic responses during a Flanker task. In addition, the critical steps for setting up the hardware and software system as well as the procedures for data acquisition and analysis were provided and discussed in detail. It is expected that the present protocol can pave a new avenue for improving the understanding of the neural mechanisms underlying various cognitive processes by using the EEG and fNIRS signals.

Introduction

This study aims to develop a working protocol to reveal the neural activation pattern underlying the Flanker task by using fused EEG and fNIRS neuroimaging techniques. Interestingly, the concurrent fNIRS-EEG recordings allow for the inspection of the relationship between the hemodynamic signals in the prefrontal cortex and various event-related potential (ERP) components of the whole brain associated with the Flanker task.

The integration of various noninvasive neuroimaging modalities including functional near-infrared spectroscopy (fNIRS), electroencephalography (EEG), and functional magnetic resonance imaging (fMRI) is essential to improv....

Protocol

Prior to the experimental tests, all participants signed informed consent documents. The protocol for the present study was approved by the Ethics Committee of the University of Macau.

1. Hardware and software setting for concurrent EEG and fNIRS recordings

1. Construct a head cap for concurrent EEG-fNIRS recordings.
   1. Select the appropriate cap size according to the head circumference of participants. In this study, use a medium-size cap since it is suitable for most adoles.......

Discussion

In this protocol, combined EEG and fNIRS recordings were performed to examine the brain activation patterns involving an event-related Flanker paradigm by recording the neural signals of the whole brain and concurrent hemodynamic responses of the prefrontal cortex. The ERP results showed that N200 at Fz was able to significantly distinguish the congruent and incongruent conditions (P=0.037). Meanwhile, the HbO signals in SFC (channels 21) also exhibited a significant difference between the congruent and incongruent condi.......

Materials

Name	Company	Catalog Number	Comments
EEG cap	EASYCAP GmbH	-	-
EEG system	BioSemi	-	-
fNIRS system	TechEn	-	CW6 System