Pharmacological fMRI provides evidence for opioidergic modulation of discrimination of facial pain expressions

Yili Zhao, Markus Rütgen, Lei Zhang, Claus Lamm

The endogenous opioid system is strongly involved in the modulation of pain. However, the potential role of this system in perceiving painful facial expressions from others has not been sufficiently explored as of yet. To elucidate the contribution of the opioid system to the perception of painful facial expressions, we conducted a double-blind, within-subjects pharmacological functional magnetic resonance imaging (fMRI) study, in which 42 participants engaged in an emotion discrimination task (pain vs. disgust expressions) in two experimental sessions, receiving either the opioid receptor antagonist naltrexone or an inert substance (placebo). On the behavioral level, participants less frequently judged an expression as pain under naltrexone as compared to placebo. On the neural level, parametric modulation of activation in the (putative) right fusiform face area (FFA), which was correlated with increased pain intensity, was higher under naltrexone than placebo. Regression analyses revealed that brain activity in the right FFA significantly predicted behavioral performance in disambiguating pain from disgust, both under naltrexone and placebo. These findings suggest that reducing opioid system activity decreased participants' sensitivity for facial expressions of pain, and that this was linked to possibly compensatory engagement of processes related to visual perception, rather than to higher level affective processes, and pain regulation.

Vienna Cognitive Science Hub, Department of Cognition, Emotion, and Methods in Psychology
Publication date
Peer reviewed
Austrian Fields of Science 2012
301210 Psychopharmacology, 501014 Neuropsychology
ASJC Scopus subject areas
Neuroscience(all), Neuropsychology and Physiological Psychology, Experimental and Cognitive Psychology, Neurology, Endocrine and Autonomic Systems, Developmental Neuroscience, Cognitive Neuroscience, Biological Psychiatry
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