Simultaneous measurement of electroencephalography and near-infrared spectroscopy during voluntary motor preparation

Takuro Zama,Sotaro Shimada

doi:10.1038/srep16438

Abstract

We investigated the relationship between electrophysiological activity and haemodynamic response during motor preparation by simultaneous recording of electroencephalography (EEG) and near-infrared spectroscopy (NIRS). It is still unknown how exactly EEG signals correlate with the haemodynamic response, although the activation in the premotor area during motor preparation has been captured by EEG and haemodynamic approaches separately. We conducted EEG-NIRS simultaneous recordings over the sensorimotor area with a self-paced button press task. Participants were instructed to press a button at their own pace after a cue was shown. The result showed that the readiness potential (RP), a negative slow potential shift occurring during motor preparation, on C3 in the extended 10–20 system occurred about 1000 ms before the movement onset. An increase in concentration of oxyhaemoglobin (oxyHb) in the premotor cortex during motor preparation was also confirmed by NIRS, which resulted in a significant correlation between the amplitude of the RP and the change in oxyHb concentration (Pearson’s correlation r2 = 0.235, p = 0.03). We show that EEG-NIRS simultaneous recording can demonstrate the correlation between the RP and haemodynamic response in the premotor cortex contralateral to the performing hand.

Highlights

The major studies on EEG-near-infrared spectroscopy (NIRS) simultaneous recording can be divided into three types depending on their purpose: i) the improvement of current source estimation with the haemodynamic response; ii) the monitoring of the haemodynamic response time-locked to the EEG signal; and iii) the investigation of the spatial/amplitude correlation between the EEG signal and the NIRS signal
Other studies have shown that the contralateral premotor cortex is activated during motor preparation, which has been measured by functional magnetic resonance imaging (fMRI)/NIRS22–27
The present study investigated whether the haemodynamic response correlates with electrophysiological signals during motor preparation

Summary

Introduction

Fazli et al.[2] found that haemodynamic responses are useful in the enhancement of EEG-based BMI performance. Other studies have shown that the contralateral premotor cortex is activated during motor preparation, which has been measured by fMRI/NIRS22–27. We hypothesized that RP and the haemodynamic response are negatively (note that RP has negative value) correlated in the premotor cortex contralateral to the performing hand during motor preparation. The NIRS signal, which has a higher S/N ratio than the EEG and a higher temporal resolution than the fMRI, may have potential to complement EEG signal (RP) for further investigation of the neural processes of motor preparation. We performed EEG-NIRS simultaneous recording during motor preparation to see whether RP and the haemodynamic response are negatively correlated in the contralateral premotor area

Methods

Results

Conclusion