The Influence of Different EEG References on Scalp EEG Functional Network Analysis During Hand Movement Tasks

Lipeng Zhang,Jinfeng Gao,Peng Wang,Yuxia Hu,Li Shi,Rui Zhang,Mingming Chen

doi:10.3389/fnhum.2020.00367

Abstract

Although scalp EEG functional networks have been applied to the study of motor tasks using electroencephalography (EEG), the selection of a suitable reference electrode has not been sufficiently researched. To investigate the effects of the original reference (REF-CZ), the common average reference (CAR), and the reference electrode standardization technique (REST) on scalp EEG functional network analysis during hand movement tasks, EEGs of 17 right-handed subjects performing self-paced hand movements were collected, and scalp functional networks [coherence (COH), phase-locking value (PLV), phase lag index (PLI)] with different references were constructed. Compared with the REF-CZ reference, the networks with CAR and REST references exhibited more significant increases in connectivity during the left-/right-hand movement preparation (MP) and movement execution (ME) stages. The node degree of the channel near the reference electrode was significantly reduced by the REF-CZ reference. CAR and REST both decreased this reference effect, REST more so than CAR. We confirmed that the choice of reference would affect the analysis of the functional network during hand movement tasks, and the REST reference can greatly reduce the effects of the online recording reference on the analysis of EEG connectivity.

Highlights

Maintaining body movement ability is one of the most important functions of the brain, and many researchers have devoted themselves to studying the mechanisms behind motor processes
For the REF-CZ reference, the connections between the contralateral respective areas of the motor cortex can be observed during the movement preparation (MP) stage, but there are few connections between these areas during the movement execution (ME) stage
The connections between the respective areas of the motor cortex areas of the networks with reference electrode standardization technique (REST) reference were more than the common average reference (CAR) reference network

Summary

Introduction

Maintaining body movement ability is one of the most important functions of the brain, and many researchers have devoted themselves to studying the mechanisms behind motor processes. After Kornhuber and Deecke first discovered the ‘‘Bereitschaftspotential’’ (BP; Kornhuber and Deecke, 1965; Shibasaki and Hallett, 2006), several studies on movement-related cortical potentials (MRCP) have been reported Pfurtscheller (1990) studied the event-related desynchronization/synchronization (ERD/ERS) of various frequency bands associated with voluntary movement. Their research demonstrated ERD over contralateral and ipsilateral motor cortices during the movement preparation (MP) and movement execution (ME). Recent developments in functional connectivity research provided a new method for neuroimaging (Biswal et al, 1995). Brain connectivity analysis has been used as a feature extraction method (Li et al, 2018b)

Results

Discussion

Conclusion