Enhanced Functional Connectivity Within Executive Function Network in Remitted or Partially Remitted MDD Patients

Area of Science:

• Neuroscience
• Psychiatry
• Cognitive Psychology

Background:

• Executive function (EF) deficits are common in major depressive disorder (MDD), leading to psychosocial dysfunction.
• Persistent EF impairment in euthymic MDD patients is often overlooked due to inconsistent research and lack of objective cognitive assessments.

Purpose of the Study:

• To investigate executive function (EF) in patients with major depressive disorder (MDD) who are in remission or partial remission.
• To explore the neural mechanisms underlying executive function (EF) in euthymic MDD patients using functional magnetic resonance imaging (fMRI).

Main Methods:

• Recruited 19 MDD patients (remitted/partially remitted) and 17 healthy controls (HCs).
• Administered multiple executive function (EF) tests and performed fMRI scans.
• Conducted seed-based functional connectivity (FC) analysis on bilateral dorsolateral prefrontal cortex (dlPFC) and fractional amplitude of low-frequency fluctuations (fALFF) analysis.

Main Results:

• MDD patients in remission/partial remission showed comparable performance on EF tests with HCs.
• MDD group exhibited increased positive functional connectivity (FC) between dlPFC regions and other brain areas (cerebellar Crus I, supramarginal gyrus) post-treatment.
• No significant group differences were found in fractional amplitude of low-frequency fluctuations (fALFF) values.

Conclusions:

• Executive function (EF) impairment persists in major depressive disorder (MDD) patients even after achieving symptom remission.
• Clinicians should consider residual cognitive symptoms, particularly executive function deficits, to enhance the effectiveness of standard therapies for MDD.