Neural Correlates of Facial Mimicry: Simultaneous Measurements of EMG and BOLD Responses during Perception of Dynamic Compared to Static Facial Expressions.

Krystyna Rymarczyk,Łukasz Żurawski,Iwona Szatkowska,Kamila Jankowiak-Siuda

doi:10.3389/fpsyg.2018.00052

Abstract

Facial mimicry (FM) is an automatic response to imitate the facial expressions of others. However, neural correlates of the phenomenon are as yet not well established. We investigated this issue using simultaneously recorded EMG and BOLD signals during perception of dynamic and static emotional facial expressions of happiness and anger. During display presentations, BOLD signals and zygomaticus major (ZM), corrugator supercilii (CS) and orbicularis oculi (OO) EMG responses were recorded simultaneously from 46 healthy individuals. Subjects reacted spontaneously to happy facial expressions with increased EMG activity in ZM and OO muscles and decreased CS activity, which was interpreted as FM. Facial muscle responses correlated with BOLD activity in regions associated with motor simulation of facial expressions [i.e., inferior frontal gyrus, a classical Mirror Neuron System (MNS)]. Further, we also found correlations for regions associated with emotional processing (i.e., insula, part of the extended MNS). It is concluded that FM involves both motor and emotional brain structures, especially during perception of natural emotional expressions.

Highlights

Facial mimicry (FM) is an unconscious and unintentional automatic response to the facial expressions of others
The present study examined neural correlates of FM during the observation of dynamic compared to static facial expressions
Proofs of concept came from facial EMG, fMRI, and combined EMG-fMRI analyses

Summary

Introduction

Facial mimicry (FM) is an unconscious and unintentional automatic response to the facial expressions of others. Observing angry facial expressions can result in enhanced activity in the viewer’s muscle responsible for frowning (CS), while viewing happy images leads to Increased activity in the facial muscle involved in smiling (ZM), and decreased activity of the CS (Hess et al, 1998; Dimberg and Petterson, 2000). There are two main psychological approaches trying to explain the mechanisms of FM. One of these is the perception-behavior link model which assumes perception and execution of a specific action show a certain overlap (Chartrand and Bargh, 1999)

Methods

Results

Conclusion