Prefrontal hyperactivation during working memory task in untreated individuals with major depressive disorder.

Area of Science:

• Neuroscience
• Psychiatry
• Cognitive Science

Background:

• The prefrontal cortex is crucial for mood, cognition, and behavior, and is implicated in major depressive disorder (MDD).
• Neuropsychological studies show working memory impairments in MDD patients.
• Few functional neuroimaging studies exist for MDD patients during working memory tasks, especially for untreated individuals.

Purpose of the Study:

• To investigate prefrontal cortex function during working memory processing in untreated patients with MDD using functional magnetic resonance imaging (fMRI).

Main Methods:

• Fifteen untreated MDD patients and 15 healthy controls underwent fMRI while performing the n-back task.
• Functional MRI data were acquired using an echo-planar imaging sequence on a GE/Elscint 2T MR system.
• Data analysis involved multiple regression using FSL-FEAT software.

Main Results:

• MDD patients exhibited significantly greater left dorsolateral cortex activation during the n-back task compared to controls (P<0.01).
• Task performance was comparable between MDD patients and healthy controls.
• MDD patients showed significant anterior cingulate cortex activation, unlike controls (P<0.01).

Conclusions:

• This study provides in vivo imaging evidence of altered frontolimbic circuit function during working memory processing in individuals with MDD.
• The findings highlight abnormal prefrontal cortex activation patterns in untreated MDD patients.
• These results contribute to understanding the neurobiological underpinnings of MDD.