Enhanced Expectation of External Sensations of the Chest Regulates the Emotional Perception of Fearful Faces.

Won-Mo Jung,In-Seon Lee,Hi-Joon Park,Yeonhee Ryu,Ye-Seul Lee,Younbyoung Chae

doi:10.3390/brainsci11070946

Abstract

Emotional perception can be shaped by inferences about bodily states. Here, we investigated whether exteroceptive inferences about bodily sensations in the chest area influence the perception of fearful faces. Twenty-two participants received pseudo-electrical acupuncture stimulation at three different acupoints: CV17 (chest), CV23 (chin), and PC6 (left forearm). All stimuli were delivered with corresponding visual cues, and the control condition included visual cues that did not match the stimulated body sites. After the stimulation, the participants were shown images with one of five morphed facial expressions, ranging from 100% fear to 100% disgust, and asked to classify them as fearful or disgusted. Brain activity was measured using functional magnetic resonance imaging during the facial expression classification task. When the participants expected that they would receive stimulation of the chest (CV17), the ratio of fearful to non-fearful classifications decreased compared to the control condition, and brain activities within the periaqueductal gray and the default mode network decreased when they viewed fearful faces. Our findings suggest that bodily sensations around the chest, but not the other tested body parts, were selectively associated with fear perception and that altering external inferences inhibited the perception of fearful faces.

Highlights

Accepted: 14 July 2021Interoceptive signals are transmitted through various visceral substrates, including those in the cardiac, gustatory, and inflammatory systems [1,2,3,4,5,6,7,8]
Paired t-test revealed a significantly lower classification ratio for fearful faces in the CV17 condition only (t = 3.104, p = 0.018; false discovery rate (FDR) corrected), which indicates that the percentage of facial expressions perceived by the participants as fearful was lower in the CV17 condition than in the control condition
When the participants viewed fearful faces in the CV17 condition, observed significantly increased brain activity in the right cuneus, fusiform gyrus, and subgenual anterior cingulate cortex we observed significantly increased brain activity in the right cuneus, fusiform gyrus, and subgenual anterior cingulate, and significantly decreased brain activity in the bilateral periaqueductal gray (PAG) and precuneus and left cortex significantly brain activity compared in the bilateral periaqueductal gray (PAG) and precuneus and left middle(sgACC), temporaland gyrus (MTG)

Summary

Introduction

Interoceptive signals are transmitted through various visceral substrates, including those in the cardiac, gustatory, and inflammatory systems [1,2,3,4,5,6,7,8]. Interoception, which refers to the processing of internal signals reflecting the state of the body, is involved in affective processing. Emotions can be shaped by internal bodily states as communicated via interoceptive signals [9,10,11]. The associations between cardiac signals and fear/threat processing have gained increasing attention from researchers. Previous reports have demonstrated that the phasic signal of the arterial baroreceptor selectively enhances the emotional impact of fearful stimuli [1,16]

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