Bupropion Administration Increases Resting-State Functional Connectivity in Dorso-Medial Prefrontal Cortex

Area of Science:

• Neuroscience
• Pharmacology
• Psychiatry

Background:

• Selective serotonergic reuptake inhibitors (SSRIs) like citalopram are associated with emotional blunting.
• Citalopram reduces resting-state functional connectivity in brain regions like the dorso-medial prefrontal cortex.
• Bupropion, a dopaminergic and noradrenergic reuptake inhibitor, is not linked to emotional blunting, but its effects on brain connectivity are unknown.

Purpose of the Study:

• To investigate the effects of bupropion on resting-state functional connectivity in healthy volunteers.
• To compare bupropion's impact on brain connectivity with that of SSRIs.
• To explore the neurobiological basis for bupropion's lack of emotional blunting.

Main Methods:

• A within-subjects, repeated-measures, double-blind, crossover design was employed.
• Seventeen healthy volunteers received 7 days of bupropion (150 mg/d) or placebo, followed by resting-state functional Magnetic Resonance Imaging.
• Seed regions were selected in the salience network (amygdala, pregenual anterior cingulate cortex) and central executive network (dorsal medial prefrontal cortex).

Main Results:

• Bupropion significantly increased resting-state functional connectivity between the dorsal medial prefrontal cortex and the posterior cingulate cortex and precuneus cortex.
• These brain regions are key components of the default mode network.
• The observed changes in connectivity were opposite to those previously found with citalopram treatment.

Conclusions:

• Bupropion exhibits a different mechanism of action compared to SSRIs.
• The findings suggest that bupropion's distinct effects on brain connectivity may explain its lack of emotional blunting.
• This research provides neurobiological insights into bupropion's therapeutic profile in depression.