Hand, foot and lip representations in primary sensorimotor cortex: a high-density electroencephalography study

Stephan P. Swinnen,Mingqi Zhao,Marco Marino,Dante Mantini,Jessica Samogin

doi:10.1038/s41598-019-55369-3

Abstract

The primary sensorimotor cortex plays a major role in the execution of movements of the contralateral side of the body. The topographic representation of different body parts within this brain region is commonly investigated through functional magnetic resonance imaging (fMRI). However, fMRI does not provide direct information about neuronal activity. In this study, we used high-density electroencephalography (hdEEG) to map the representations of hand, foot, and lip movements in the primary sensorimotor cortex, and to study their neural signatures. Specifically, we assessed the event-related desynchronization (ERD) in the cortical space. We found that the performance of hand, foot, and lip movements elicited an ERD in beta and gamma frequency bands. The primary regions showing significant beta- and gamma-band ERD for hand and foot movements, respectively, were consistent with previously reported using fMRI. We observed relatively weaker ERD for lip movements, which may be explained by the fact that less fine movement control was required. Overall, our study demonstrated that ERD based on hdEEG data can support the study of motor-related neural processes, with relatively high spatial resolution. An interesting avenue may be the use of hdEEG for deeper investigations into the pathophysiology of neuromotor disorders.

Highlights

The primary sensorimotor cortex plays a major role in the execution of movements of the contralateral side of the body
Transcranial magnetic stimulation (TMS) has been used to examine the functional organization of the primary motor cortex[3,4]; its spatial specificity may not be sufficient to disentangle the representation of different body parts
We aim to demonstrate that source localizations of high-density electroencephalography (hdEEG) data can yield a spatial accuracy comparable to that of functional magnetic resonance imaging (fMRI) results, at least for cortical regions

Summary

Introduction

The primary sensorimotor cortex plays a major role in the execution of movements of the contralateral side of the body. We used high-density electroencephalography (hdEEG) to map the representations of hand, foot, and lip movements in the primary sensorimotor cortex, and to study their neural signatures. To investigate the functional organization of the primary sensorimotor cortex, early studies used direct electrical stimulation through implanted electrodes[2] This technique is still used for mapping brain function, the focus of neuroscientific research has shifted toward the use of noninvasive methods. FMRI has shown large reproducibility in mapping of primary motor cortex, as assessed by test-retest analyses[8,9] This technique can provide spatial maps with relatively high www.nature.com/scientificreports resolution, the measured signal is mediated by a slow hemodynamic response. This permitted us to detect multiple brain networks that were spatially similar to corresponding networks obtained from fMRI data[28]

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