title: Reduced amygdala and ventral striatal activity to happy faces in PTSD is associated with emotional numbing.
abstract: There has been a growing recognition of the importance of reward processing in PTSD, yet little is known of the underlying neural networks. This study tested the predictions that (1) individuals with PTSD would display reduced responses to happy facial expressions in ventral striatal reward networks, and (2) that this reduction would be associated with emotional numbing symptoms. 23 treatment-seeking patients with Posttraumatic Stress Disorder were recruited from the treatment clinic at the Centre for Traumatic Stress Studies, Westmead Hospital, and 20 trauma-exposed controls were recruited from a community sample. We examined functional magnetic resonance imaging responses during the presentation of happy and neutral facial expressions in a passive viewing task. PTSD participants rated happy facial expression as less intense than trauma-exposed controls. Relative to controls, PTSD participants revealed lower activation to happy (-neutral) faces in ventral striatum and and a trend for reduced activation in left amygdala. A significant negative correlation was found between emotional numbing symptoms in PTSD and right ventral striatal regions after controlling for depression, anxiety and PTSD severity. This study provides initial evidence that individuals with PTSD have lower reactivity to happy facial expressions, and that lower activation in ventral striatal-limbic reward networks may be associated with symptoms of emotional numbing.
authors.affiliation: School of Psychology, University of New South Wales, Sydney, Australia; Brain Dynamics Centre, Westmead Millennium Institute, Westmead Hospital, Sydney, Australia; School of Psychology, University of Tasmania, Hobart, Australia.
authors.forename: Kim L
authors.initials: KL
authors.lastname: Felmingham
authors.affiliation: Brain Dynamics Centre, Westmead Millennium Institute, Westmead Hospital, Sydney, Australia.
authors.forename: Erin M
authors.initials: EM
authors.lastname: Falconer
authors.affiliation: Brain Dynamics Centre, Westmead Millennium Institute, Westmead Hospital, Sydney, Australia; Western Clinical School, University of Sydney, Sydney, Australia.
authors.forename: Leanne
authors.initials: L
authors.lastname: Williams
authors.affiliation: School of Psychology, University of Sydney, Sydney, Australia.
authors.forename: Andrew H
authors.initials: AH
authors.lastname: Kemp
authors.affiliation: Brain Dynamics Centre, Westmead Millennium Institute, Westmead Hospital, Sydney, Australia; School of Psychology, University of Tasmania, Hobart, Australia.
authors.forename: Adrian
authors.initials: A
authors.lastname: Allen
authors.affiliation: MRI Unit, Department of Radiology, Westmead Hospital, Sydney, Australia.
authors.forename: Anthony
authors.initials: A
authors.lastname: Peduto
authors.affiliation: Brain Dynamics Centre, Westmead Millennium Institute, Westmead Hospital, Sydney, Australia; School of Psychology, University of Tasmania, Hobart, Australia.
authors.forename: Richard A
authors.initials: RA
authors.lastname: Bryant
mesh_terms: D000293:Adolescent; D000328:Adult; D000679:Amygdala / Q000473:pathology / Q000503:physiopathology*; D001931:Brain Mapping; D016022:Case-Control Studies; D005149:Facial Expression; D005260:Female; D006240:Happiness; D006801:Humans; D007266:Inhibition, Psychological; D008297:Male; D008875:Middle Aged; D009415:Nerve Net / Q000473:pathology / Q000503:physiopathology*; D010364:Pattern Recognition, Visual; D012201:Reward; D013313:Stress Disorders, Post-Traumatic / Q000473:pathology / Q000503:physiopathology* / Q000523:psychology; D066328:Ventral Striatum / Q000473:pathology / Q000503:physiopathology*