Association of acute depressive symptoms and functional connectivity in emotional processing regions following sport-related concussion

Abstract

Few studies have examined the physiologic correlates of depressive symptoms following sport-related concussion (SRC), despite the prevalence of these symptoms following brain injury. We hypothesized that concussed athletes would have disrupted resting-state functional connectivity in emotional processing regions compared to controls, and that this disruption would be associated with greater post-concussion symptoms of depression. Forty-three concussed athletes at approximately 1 day (N = 34), 1 week (N = 34), and 1 month (N = 30) post-concussion were evaluated along with 51 healthy athletes assessed at a single visit. Resting-state fMRI was collected on a 3T GE scanner (TR = 2s); depressive symptoms were assessed using the Hamilton Rating Scale for Depression (HAM-D). Emotional processing regions of interest (ROI) were defined using an automated meta-analysis of brain regions associated with the term “emotion”. Fisher-Z transformed correlations were calculated between each ROI. A multivariate approach assessed connectivity by analyzing ROI as simultaneous response variables. Concussed athletes had significantly higher depressive symptoms relative to controls at all time points but showed partial recovery by 1-month post-concussion relative to earlier visits (p's< 0.05). Functional connectivity did not differ between controls and concussed athletes at 1 day or one-week post-concussion. However, concussed athletes had significantly different connectivity in regions associated with emotional processing at 1 month relative to 1 day post-concussion (p = 0.002), and relative to controls (p = 0.003). Follow-up analyses showed that increased connectivity between attention and default mode networks at 1-month post-concussion was common across both analyses. In addition, functional connectivity of emotional processing regions was significantly associated with depressive symptoms at 1 day (p = 0.003) and one-week post-concussion (p = 7 × 10-8), with greater HAM-D scores correlating with decreased connectivity between attention and default mode networks. These results suggest that intrinsic connectivity between default mode and attention regions following SRC may be compensatory in nature.