IMR Press / JIN / Volume 18 / Issue 1 / DOI: 10.31083/j.jin.2019.01.101
Open Access Original Research
Variability in anterior insula grey matter volume correlates with awareness for peri-threshold backward-masked fearful faces
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1 Department of Pharmacy Practice, Wayne State University, Detroit, MI 48201, USA
2 Department of Psychology, Colorado State University, Fort Collins, Colorado 80523, USA
3 Strategic Hub for Psychology, Social Work, Health Behaviours and Addictions Media Culture and Society, University of the West of Scotland ,Paisley, Scotland, PA1, 2BE, UK
4 Department of Psychological Science, Northern Michigan University, Marquette, MI 49855, USA
*Correspondence: (Robert D. Torrence)
J. Integr. Neurosci. 2019, 18(1), 11–15;
Submitted: 9 August 2017 | Accepted: 15 February 2018 | Published: 30 March 2019
Copyright: © 2019 Torrence et al. Published by IMR press.
This is an open access article under the CC BY-NC 4.0 license (

The threshold for conscious perception of stimuli within the environment varies from individual to individual. Functional neuroimaging studies have suggested that insular cortex activity is positively correlated with perceptual awareness. However, few studies have tested the relationship between awareness and structural variability in the insula. The purpose of this study was to examine structural differences in brain morphology related to perceptual awareness of fearful faces. This study hypothesized that there would be a positive correlation between insular grey matter volume and scores on the forced-choice awareness check task. The forced-choice awareness check task was designed to assess awareness for the presence and location of backward masked fearful and neutral faces, masked with neutral faces. The participants responded by indicating the side on which the masked fearful face appeared, or whether there were two neutral faces. The task included a total of 60 trials. T1-weighted magnetic resonance images were collected to measure grey matter volumes. Individuals that were more aware of backward masked fearful faces had greater grey matter volume in the insula, middle cingulate, anterior temporal pole, ventral striatum, and hippocampus.

voxel-based morphometry
backward masked
fearful facial expressions
Figure 1.
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