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

Area of Science:

• Neuroscience
• Psychiatry
• Cognitive Neuroscience

Background:

• Major depressive disorder (MDD) is characterized by abnormal resting-state neural activity within the default-mode network (DMN).
• Previous research indicates negative blood oxygenation level-dependent (BOLD) responses (NBRs) in DMN regions are altered in MDD.

Purpose of the Study:

• To investigate neural activity in DMN regions during self-related emotional judgment and passive picture viewing in MDD patients and healthy controls.
• To explore the association between DMN activity, self-relatedness, and depressive symptoms.

Main Methods:

• Event-related functional magnetic resonance imaging (fMRI) was employed.
• Twenty-five patients with MDD and 25 healthy controls participated.
• Participants engaged in tasks involving self-related emotional judgment and passive picture viewing.

Main Results:

• MDD subjects reported higher self-relatedness, correlating with depression severity.
• MDD patients exhibited reduced NBRs in anterior medial cortical regions during self-related judgment.
• Posterior medial regions showed increased NBRs in MDD patients, unlike healthy controls.
• Anterior medial cortical NBRs in MDD were not modulated by the degree of self-relatedness.

Conclusions:

• Reduced anterior DMN NBRs in MDD may reflect a decoupling from self-relatedness.
• This decoupling could lead to an abnormal increase in self-focus in individuals with MDD.
• Findings highlight potential neural mechanisms underlying self-referential processing deficits in depression.