Reduced negative BOLD responses in the default-mode network and increased self-focus in depression

Abstract

Objectives. Functional imaging studies in major depressive disorder (MDD) indicate abnormal resting state neural activity and negative blood oxygenation level-dependent (BOLD) responses (NBRs) in regions of the default-mode network (DMN). Methods. Since activity in DMN regions has been associated with self-relatedness, we investigated neural activity in these regions during self-related emotional judgement and passive picture viewing in 25 patients with MDD and 25 healthy controls in an event-related fMRI design. Results. Behaviourally, MDD subjects showed significantly higher ratings of self-relatedness that also correlated with depression symptoms such as hopelessness. Neuroimaging results in MDD patients showed significantly lower negative BOLD responses (NBRs) in anterior medial cortical regions during judgement of self-relatedness while posterior medial regions showed increased NBRs. Unlike in healthy subjects, the anterior medial cortical NBRs were no longer parametrically modulated by the degree of self-relatedness in MDD patients. Conclusions. Our findings suggest that reduced NBRs in the anterior regions of the default-mode network may signify decoupling from self-relatedness in MDD patients with the consecutive abnormal increase of self-focus.

Key words::

• Default-mode network
• negative BOLD responses
• major depression
• self-related processing
• event-related fMRI

Acknowledgements

The study was supported a grant from the German Research Foundation (DFG-SFB 779/A6 to GN), the Swiss National Research Foundation (3100A0-100830) to GN and HB, a grant of the Research Foundation at the University of Zurich, a grant from ETH Zurich (SEP) and Philips Medical Systems, Best, NL, to PB, the Hartmann-Müller-Foundation to HB/GN, the Gebert-Rüf-Foundation to HB/GN, as well as grants from the Hope of Depression Research Foundation (HDRF/ISAN), CRC, CIHR, EJLB-Michael Smith Foundation to GN. The funding sources had no further role in study design; in the collection, analysis and interpretation of data; in the writing of the report; and in the decision to submit the paper for publication.

Statement of Interest

None to declare.