Co-occurring anxiety influences patterns of brain activity in depression

Abstract

Brain activation associated with anhedonic depression and co-occurring anxious arousal and anxious apprehension was measured by fMRI during performance of an emotion word Stroop task. Consistent with EEG findings, depression was associated with rightward frontal lateralization in the dorsolateral prefrontal cortex (DLPFC), but only when anxious arousal was elevated and anxious apprehension was low. Activity in the right inferior frontal gyrus (IFG) was also reduced for depression under the same conditions. In contrast, depression was associated with more activity in the anterior cingulate cortex (dorsal ACC and rostral ACC) and the bilateral amygdala. Results imply that depression, particularly when accompanied by anxious arousal, may result in a failure to implement top-down processing by appropriate brain regions (left DLPFC, right IFG) due to increased activation in regions associated with responding to emotionally salient information (right DLPFC, amygdala).

Figure 1

Regions showing anhedonic depression two-way interactions with anxiety for negative – neutral contrast. Top panel: R DLPFC from Anhedonic Depression × Anxious Arousal interaction. Bottom panel: R Lateral Occipital Cortex, inferior division from Anhedonic Depression × Anxious Apprehension interaction. Graphing of the two-way interactions show that depression's relationship with R DLPFC activation depends on the level of co-occurring anxious arousal, and that the relationship with right occipital cortex depends on the level of co-occurring anxious apprehension. Highlighted voxels are those with z-scores > 2.05 (p < .04) meeting a cluster-size threshold of 215 (corrected p < .05).

Figure 2

Laterality analyses for regions with two-way interactions for negative – neutral contrast. Graphing of the two-way interactions for the laterality index for the Anhedonic Depression × Anxious Arousal (top panel) and Anhedonic Depression × Anxious Apprehension (bottom panel) ROIs support the interpretation that depression is associated with increased rightward activity when co-occurring anxiety is high.

Figure 3

L DLPFC Anhedonic Depression × Anxious Arousal × Anxious Apprehension interaction for negative – neutral contrast. Highlighted voxels are those with z-scores > 2.05 (p < .04) meeting a cluster-size threshold of ≥ 215 (corrected p < .05). Graphing of the three-way interaction show decreased left DLPFC with increased depression, only when anxious apprehension is low and anxious arousal is high (top panel). Graphing of the three-way interaction for this region's laterality index is also shown (bottom panel).

Figure 4

R IFG Anhedonic Depression × Anxious Arousal × Anxious Apprehension interaction for negative – neutral contrast. Highlighted voxels are those with z-scores > 2.05 (p < .04) meeting a cluster-size threshold of ≥ 215 (corrected p < .05). Graphing of the three-way interaction show reduced of R IFG with increased depression, only when anxious apprehension is low and anxious arousal is high (top panel). Graphing of the three-way interaction for this region's laterality index is also shown (bottom panel).

Figure 5

R temporal gyrus Anhedonic Depression × Anxious Arousal interaction for arousal contrast. Highlighted voxels are those with z-scores > 2.05 (p < .04) meeting a cluster-size threshold of ≥ 215 (corrected p < .05). Graphing of the two-way interaction (top panel) shows that the relationship between depression and right-posterior activity depends on the level of co-occurring anxious arousal. Graphing of the two-way interaction for this region's laterality index is also shown (bottom panel).

Figure 6

Regions where anhedonic depression captured unique variance or shared variance with anxious arousal for negative – neutral contrast. Highlighted voxels are those with z-scores > 2.17 (p < .03), cluster size ≥ 156 voxels (corrected p < .05), display slice x = -2. Left panel: Anhedonic depression captured unique variance in dACC and rACC. Right Panel: Posterior cingulate region identified from the Anhedonic Depression & Anxious Arousal conjunction analysis.