Background: Pro-inflammatory cytokines are associated with sickness behaviors, a set of behaviors including low mood, which are orchestrated by the brain and described as shift in motivational state. The present study investigated the hypothesis that local inflammation is associated with greater subgenual anterior cingulate cortex (sACC) activation in persons undergoing chronic stress.
Methods: Women undergoing the emotional stress of bereavement had fMRI scans during a grief elicitation task. Local inflammation was measured by salivary concentrations of two markers of pro-inflammatory cytokine activity (e.g., interleukin-1beta and soluble tumor necrosis factor receptor II).
Results: Analyses revealed that both inflammatory markers were positively associated with ventral prefrontal activation (e.g., sACC and orbitofrontal cortex) as well as other regions important in the emotional task such as noun retrieval (e.g., temporal cortex), and visual processing (e.g., cuneus and fusiform gyrus). In separate analyses, the ventral prefrontal activations correlated with free recall of grief-related word stimuli, but not neutral word stimuli.
Conclusions: This is the first study to demonstrate the relationship between emotional processing, regional brain activation and localized inflammation in a chronically stressed population of adults.