Studies of fMRI scans of women from whom grief was elicited about the death of a mother or a sister in the past 5 years resulted in the conclusion that grief produced a local inflammation response as measured by salivary concentrations of pro-inflammatory cytokines. These responses were correlated with activation in the anterior cingulate cortex and orbitofrontal cortex. This activation also correlated with the free recall of grief-related word stimuli. This suggests that grief can cause stress, and that this reaction is linked to the emotional processing parts of the frontal lobe. Activation of the anterior cingulate cortex and vagus nerve is similarly implicated in the experience of heartbreak whether due to social rejection or bereavement.