Functional connectivity of the prefrontal cortex and amygdala is related to depression status in major depressive...

We used resting-state functional magnetic resonance imaging to examine possible amygdala-prefrontal cortex functional connectivity abnormalities and to clarify the correlation of the abnormal connectivity with response to antidepressant medications.

We recruited 40 drug-naïve patients with first-episode depression, had a 17-item Hamilton Rating Scale for Depression (HRSD17) score>17 for participation in a magnetic resonance imaging scan. Remission was defined as an HRSD17 score <7 following 8 weeks of fluoxetine antidepressant treatment. Gender- and age-matched healthy subjects (n = 26) also underwent MRI scanning. Finally, the association between the change in HRSD17 scores and a change in connectivity between the amygdala and prefrontal cortex from pre to post-treatment was evaluated in major depressive disorder (MDD).

After controlling for age, gender and years of education, a statistically significant increase in functional connectivity to the right prefrontal cortex from the amygdala was observed in the MDD group compared with the healthy control group (p<0.05, corrected). After 8 weeks of antidepressant treatment and remission in the MDD group, a significant decrease in functional connectivity to the right prefrontal cortex and the left prefrontal cortex from the amygdala was observed, compared with the level of connectivity in the drug-naïve MDD group(p<0.05,corrected). There were no significant associations between the difference in HRSD17 scores rMDD and fMDD with the change in connectivity.

The design of this study lack resistance to treatment for the depressed group.

Increased functional connectivity of PFC-AMY is a promise to be a biomarker of MDD, however weather it could be a biomarker of fluoxetine treatment needs future studying.