The study showed that the brain's natural painkiller system responds to social rejection and not just physical injury.
The team, based at by University of Michigan Medical School's Molecular and Behavioral Neuroscience Institute combined advanced brain scanning that can track chemical release in the brain with a model of social rejection based on online dating.
The study's lead author, David T. Hsu, Ph.D., said the new research on social rejection suggested that the brain pathways that are activated during physical pain and social pain are similar.
The study involved 18 adults who were asked to view photos and fictitious personal profiles of hundreds of other adults. Each selected some who they might be most interested in romantically- a setup similar to online dating.
But then, when the participants were lying in a brain imaging machine called a PET scanner, they were informed that the individuals they found attractive and interesting were not interested in them.
Brain scans made during these moments showed opioid release, measured by looking at the availability of mu-opioid receptors on brain cells. The effect was largest in the brain regions called the ventral striatum, amygdala, midline thalamus, and periaqueductal gray - areas that are also known to be involved in physical pain.
Hsu notes that the underlying personality of the participants appeared to play a role in how much of a response their opioid systems made.
"Individuals who scored high for the resiliency trait on a personality questionnaire tended to be capable of more opioid release during social rejection, especially in the amygdala," a region of the brain involved in emotional processing, Hsu said.
"This suggests that opioid release in this structure during social rejection may be protective or adaptive," he said.
The more opioid release during social rejection in another brain area called the pregenual cingulate cortex, the less the participants reported being put in a bad mood by the news that they'd been snubbed.
The study is published in Molecular Psychiatry.
--ANI (Posted on 12-10-2013)