title: Reduced cerebral blood flow within the default-mode network and within total gray matter in major depression.
abstract: The default-mode network (DMN) was shown to have aberrant blood oxygenation-level-dependent (BOLD) activity in major depressive disorder (MDD). While BOLD is a relative measure of neural activity, cerebral blood flow (CBF) is an absolute measure. Resting-state CBF alterations have been reported in MDD. However, the association of baseline CBF and CBF fluctuations is unclear in MDD. Therefore, the aim was to investigate the CBF within the DMN in MDD, applying a strictly data-driven approach. In 22 MDD patients and 22 matched healthy controls, CBF was acquired using arterial spin labeling (ASL) at rest. A concatenated independent component analysis was performed to identify the DMN within the ASL data. The perfusion of the DMN and its nodes was quantified and compared between groups. The DMN was identified in both groups with high spatial similarity. Absolute CBF values within the DMN were reduced in MDD patients (p<0.001). However, after controlling for whole-brain gray matter CBF and age, the group difference vanished. In patients, depression severity was correlated with reduced perfusion in the DMN in the posterior cingulate cortex and the right inferior parietal lobe. Hypoperfusion within the DMN in MDD is not specific to the DMN. Still, depression severity was linked to DMN node perfusion, supporting a role of the DMN in depression pathobiology. The finding has implications for the interpretation of BOLD functional magnetic resonance imaging data in MDD.
authors.affiliation: Department of Psychiatric Neurophysiology, University Hospital of Psychiatry, Bolligenstrasse 111, Bern, Switzerland.
authors.forename: Ariane
authors.initials: A
authors.lastname: Orosz
authors.forename: Kay
authors.initials: K
authors.lastname: Jann
authors.forename: Andrea
authors.initials: A
authors.lastname: Federspiel
authors.forename: Helge
authors.initials: H
authors.lastname: Horn
authors.forename: Oliver
authors.initials: O
authors.lastname: Höfle
authors.forename: Thomas
authors.initials: T
authors.lastname: Dierks
authors.forename: Roland
authors.initials: R
authors.lastname: Wiest
authors.forename: Werner
authors.initials: W
authors.lastname: Strik
authors.forename: Thomas
authors.initials: T
authors.lastname: Müller
authors.forename: Sebastian
authors.initials: S
authors.lastname: Walther
mesh_terms: D000704:Analysis of Variance; D001783:Blood Flow Velocity / Q000502:physiology; D001921:Brain / Q000098:blood supply*; D016022:Case-Control Studies; D002560:Cerebrovascular Circulation / Q000502:physiology; D003865:Major Depressive Disorder / Q000503:physiopathology*; D005260:Female; D006801:Humans; D018810:Magnetic Resonance Angiography; D008297:Male; D008875:Middle Aged