Amygdala reactivity to fearful faces correlates positively with impulsive aggression

ABSTRACT

Facial expressions robustly activate the amygdala, a brain structure playing a critical role in aggression. Whereas previous studies suggest that amygdala reactivity is related to various measures of impulsive aggression, we here estimate a composite measure of impulsive aggression and evaluate whether it is associated with amygdala reactivity to angry and fearful faces. We estimated amygdala reactivity with functional magnetic resonance imaging in 47 men with varying degree of aggressive traits (19 incarcerated violent offenders and 28 healthy controls). We modeled a composite “impulsive aggression” trait construct (LV_agg) using a linear structural equation model, with a single latent variable capturing the shared correlation between five self-report measures of trait aggression, anger and impulsivity. We tested for associations between amygdala reactivity and the LV_agg, adjusting for age and group. The LV_agg was significantly positively associated with amygdala reactivity to fearful (p = 0.001), but not angry faces (p = 0.9). We found no group difference in amygdala reactivity to fearful or angry faces. The findings suggest that that amygdala reactivity to fearful faces is represented by a composite index of impulsive aggression and provide evidence that impulsive aggression is associated with amygdala reactivity in response to submissive cues, i.e., fearful faces.

KEYWORDS:

• Impulsivity
• fMRI
• neuroimaging
• psychopathy
• aggression
• violent offenders

Acknowledgments

We thank all the volunteers for kindly participating in this study and the prison staff for the collaboration. The excellent technical assistance of Lone Ibsgaard Freyr, Erik Perfalk, Martin Korsbak Madsen and Gerda Thomsen is gratefully acknowledged.

Disclosure statement

No potential conflict of interest was reported by the authors.

Financial Disclosure

Dr. Knudsen has received honoraria as a consultant for H. Lundbeck A/S, as a member of the steering group for Brain Prize. She is also on the advisory board for the Kristian G. Jebsen Foundation and a field editor for Int J Neuropsychopharm

Supplemental material

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Additional information

Funding

This work was supported by the Danish Council for Independent Research [grant number 1331-00328] and Rigshospitalets Research Council [grant numbers R49-A1646, R65-A2250]. The funding sources were not involved in the study design or in the collection, analysis, writing or publication of data.