Baseline vagal tone predicts BOLD response during elicitation of grief

Previous studies of the relationship between autonomic and central nervous system activity using fMRI have primarily utilized cognitive, motor or conditioning tasks. The present study investigated the association between the regional brain activity during the evocation of grief and baseline parasympathetic activity. Eight right-handed women who had experienced the death of a loved one in the past 18 months were scanned during the presentation of personalized pictures and words that evoked grief and had a measure of baseline parasympathetic activity taken. Greater posterior cingulate cortex (PCC) activity was associated with lower parasympathetic activity (eg more arousal). Connectivity has been demonstrated between the ventral PCC (vPCC) and the subgenual ACC (sACC), which then projects to the autonomic nuclei. In the present study, functional connectivity analysis revealed a positive correlation between vPCC and sACC/orbitofrontal cortical activity. Additionally, bilateral cuneus and parahippocampus were associated with higher baseline parasympathetic tone, important to visual perception in emotional processing and episodic memory respectively. Future studies should compare differences between central and peripheral arousal in complicated and non-complicated grief.