Amygdala Activation and Connectivity to Emotional Processing Distinguishes Asymptomatic Patients With Bipolar Disorders and Unipolar Depression

Mayuresh S Korgaonkar; May Erlinger; Isabella A Breukelaar; Philip Boyce; Philip Hazell; Cassandra Antees; Sheryl Foster; Stuart M Grieve; Lavier Gomes; Leanne M Williams; Anthony W F Harris; Gin S Malhi

doi:10.1016/j.bpsc.2018.08.012

Amygdala Activation and Connectivity to Emotional Processing Distinguishes Asymptomatic Patients With Bipolar Disorders and Unipolar Depression

Biol Psychiatry Cogn Neurosci Neuroimaging. 2019 Apr;4(4):361-370. doi: 10.1016/j.bpsc.2018.08.012. Epub 2018 Aug 31.

Authors

Affiliations

¹ Brain Dynamics Centre, Westmead Institute for Medical Research, The University of Sydney, New South Wales, Australia; Discipline of Psychiatry, University of Sydney School of Medicine, New South Wales, Australia. Electronic address: M.Korgaonkar@sydney.edu.au.
² Brain Dynamics Centre, Westmead Institute for Medical Research, The University of Sydney, New South Wales, Australia.
³ Discipline of Psychiatry, University of Sydney School of Medicine, New South Wales, Australia.
⁴ Department of Radiology, Westmead Hospital, Westmead, New South Wales, Australia; Discipline of Medical Radiation Sciences, Faculty of Health Science, The University of Sydney, New South Wales, Australia.
⁵ Sydney Translational Imaging Laboratory, Heart Research Institute, Charles Perkins Centre and University of Sydney School of Medicine, New South Wales, Australia; Department of Radiology, Royal Prince Alfred Hospital, Camperdown, New South Wales, Australia.
⁶ Department of Radiology, Westmead Hospital, Westmead, New South Wales, Australia.
⁷ Brain Dynamics Centre, Westmead Institute for Medical Research, The University of Sydney, New South Wales, Australia; Psychiatry and Behavioral Sciences, Stanford University, Stanford, Palo Alto, California; Sierra-Pacific Mental Illness Research, Education, and Clinical Center, Palo Alto Veterans Affairs Health Care System, Palo Alto, California.
⁸ Brain Dynamics Centre, Westmead Institute for Medical Research, The University of Sydney, New South Wales, Australia; Discipline of Psychiatry, University of Sydney School of Medicine, New South Wales, Australia.
⁹ Discipline of Psychiatry, University of Sydney School of Medicine, New South Wales, Australia; Clinical Assessment Diagnostic Evaluation (CADE) Clinic, Department of Psychiatry, Royal North Shore Hospital, Sydney, New South Wales, Australia.

PMID: 30343134
DOI: 10.1016/j.bpsc.2018.08.012

Abstract

Background: Mechanistically based neural markers, such as amygdala reactivity, offer one approach to addressing the challenges of differentiating bipolar and unipolar depressive disorders independently from mood state and acute symptoms. Although emotion-elicited amygdala reactivity has been found to distinguish patients with bipolar depression from patients with unipolar depression, it remains unknown whether this distinction is traitlike and present in the absence of an acutely depressed mood. We addressed this gap by investigating patients with bipolar disorder (BP) and unipolar major depressive disorder (MDD) in remission.

Methods: Supraliminal and subliminal processing of faces exhibiting threat, sad, happy, and neutral emotions during functional magnetic resonance imaging was completed by 73 participants (23 BP patients and 25 MDD patients matched for age and gender, number of depressive episodes and severity; 25 age- and gender-matched healthy control subjects). We compared groups for activation and connectivity for the amygdala.

Results: BP patients had lower left amygdala activation than MDD patients during supraliminal and subliminal threat, sad, and neutral emotion processing and for subliminal happy faces. BP patients also exhibited lower amygdala connectivity to the insula and hippocampus for threat and to medial orbitofrontal cortex for happy supraliminal and subliminal processing. BP patients also demonstrated greater amygdala-insula connectivity for sad supraliminal and subliminal face processing. Both patient groups were distinct from control subjects across several measures for activation and connectivity.

Conclusions: Independent of valence or level of emotional awareness, amygdala activation and connectivity during facial emotion processing can distinguish BP patients and MDD patients. These findings provide evidence that this neural substrate could be a potential trait marker to differentiate these two disorders largely independent of illness state.

Keywords: Amygdala; Bipolar disorders; Depression; Emotion processing; Remission; fMRI connectivity.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Adolescent
Adult
Amygdala / diagnostic imaging
Amygdala / physiopathology*
Bipolar Disorder / diagnostic imaging
Bipolar Disorder / physiopathology*
Cerebral Cortex / diagnostic imaging
Cerebral Cortex / physiopathology*
Connectome*
Depressive Disorder, Major / diagnostic imaging
Depressive Disorder, Major / physiopathology*
Emotions / physiology*
Facial Expression
Facial Recognition / physiology*
Female
Hippocampus / diagnostic imaging
Hippocampus / physiopathology
Humans
Magnetic Resonance Imaging
Male
Middle Aged
Remission Induction
Social Perception
Subliminal Stimulation
Young Adult