Antidepressant treatment normalizes hypoactivity in dorsolateral prefrontal cortex during emotional interference processing in major depression

Abstract

Background: Major depression (MDD) is characterized by altered emotion processing and deficits in cognitive control. In cognitive interference tasks, patients with MDD have shown excessive amygdala activity and under-recruitment of dorsolateral prefrontal cortex (DLPFC). The purpose of this study was to examine the effects of antidepressant treatment on anomalous neural activity in cognitive-control and emotion-processing circuitry.

Methods: Functional magnetic resonance imaging was conducted on depressed patients (n=23) (both before and after antidepressant treatment) compared with matched controls (n=18) while they performed a cognitive task involving attended and unattended fear-related stimuli.

Results: After eight weeks of SSRI antidepressant treatment, patients with depression showed significantly increased DLPFC activity to unattended fear-related stimuli and no longer differed from controls in either DLPFC or amygdala activity.

Conclusions: These results suggest that antidepressant treatment increases DLPFC under-activity during cognitive tasks that include emotional interference.

Limitations: The sample was fairly homogeneous and this may limit generalizability.

Figures

Figure 1

Fear-minus-neutral activity in the right dorsolateral prefrontal cortex and left amygdala. These regions showed a significant three-way interaction of attention × emotion × group at time-1. The graphs show percent change in signal magnitude. Error bars indicate standard errors. Time 1 indicates pre-treatment activations. Time 2 indicates post-antidepressant treatment activations. AF is shorthand for attend fearful faces minus attend neutral faces (see Methods). IF indicates ignore fearful faces minus ignore neutral faces.