Ketamine differentially influences healthy subjects and depressed patients’ neural responses in the amygdala during emotion processing

Authors

• J Szczepanik
• J Ihne
• A Nugent
• ML Furey
• CA Zarate

Abstract

Ketamine produces rapid antidepressant effects in Major Depressive Disorder(MDD) The amygdala is implicated in MDD and is critical in processing of emotional stimuli. We investigated how ketamine modulates neural responses to emotional face stimuli in the amygdala in healthy control (HC) subjects and MDD patients to help elucidate the antidepressant mechanism of action of ketamine. Twenty-four HC subjects and 30 un-medicated MDD patients participated in an fMRI dot-probe task before and after i.v. ketamine(.5mg/kg). Following the presentation of one emotional(happy/angry) and one neutral face, a dot was presented. Participants responded to the location of the dot. Amygdala ROI BOLD responses were examined for happy and angry conditions before and after ketamine. Significant drug*group interactions were found in the left(ANOVA, F=5.91, p=0.019) and right(F=10.78, p=0.002) amygdala, and a main effect of emotion in the right amygdala(F=5.18, p=0.027). T-tests showed baseline differences during happy trials in the left amygdala (HC>MDD, p=0.009) and during angry trials in the right amygdala (HC>MDD, p=0.001). Post-ketamine, groups differed in left amygdala activation to angry trials (MDD>HC, p=0.033). Within groups, HC showed decreased activation to angry emotion(p

Scientific Focus Area: Neuroscience

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