Amygdala volume predicts inter-individual differences in fearful face recognition.

Ke Zhao,Xiaolan Fu,Xi-Nian Zuo,Wen-Jing Yan,Yu-Hsin Chen,Emmanuel Andreas Stamatakis

doi:10.1371/journal.pone.0074096

Abstract

The present study investigates the relationship between inter-individual differences in fearful face recognition and amygdala volume. Thirty normal adults were recruited and each completed two identical facial expression recognition tests offline and two magnetic resonance imaging (MRI) scans. Linear regression indicated that the left amygdala volume negatively correlated with the accuracy of recognizing fearful facial expressions and positively correlated with the probability of misrecognizing fear as surprise. Further exploratory analyses revealed that this relationship did not exist for any other subcortical or cortical regions. Nor did such a relationship exist between the left amygdala volume and performance recognizing the other five facial expressions. These mind-brain associations highlight the importance of the amygdala in recognizing fearful faces and provide insights regarding inter-individual differences in sensitivity toward fear-relevant stimuli.

Highlights

Fearful faces convey signals of potential threat, and recognizing such facial expressions with precision in conspecifics is evolutionarily advantageous [1,2]
It is reasonable to hypothesize based on these studies of patients and normal adults that a smaller amygdala might be more sensitive to fear-relevant stimuli, such as fearful faces [30], and that performance when recognizing fearful faces could be predicted by the variation in volume between individuals
Our results show that the volume of the left amygdala negatively correlated with the subjects’ accuracy on fearful face recognition in Test 1 (r = 20.61, p = 0.001, power = 0.94), Test 2 (r = 20.43, p = 0.03, power = 0.66), and the average of the two tests (r = 20.66, p,0.001, power = 0.98) (Figure 2 and Table 1)

Summary

Introduction

Fearful faces convey signals of potential threat, and recognizing such facial expressions with precision in conspecifics is evolutionarily advantageous [1,2]. Reduced or decreased amygdala volume has been observed in patients with spider phobia [21], posttraumatic stress disorder (PTSD) [22,23], and pediatric anxiety ( social phobia) [24], compared to normal adults. These patients are thought to have an increased sensitivity to specific fear-related stimuli [21,22,23,24,25], such as patients with social phobia being more sensitive to critical facial expressions [26]. Factors such as the intensity of fear in the presented images and the participants’ trait anxiety levels were considered [27,32,33,34,35] to obtain a more comprehensive understanding of the relationship between amygdala volume and performance in fearful face recognition

Methods

Results

Discussion