Archive for August 2009
An interesting article to finish up science week on the nook. This one really won't need too much of an introduction as the title says it all—a broken heart really does physically hurt. Here is the full excerpt from the above-linked layman's version of the scientific paper:
Scientists have identified a genetic link between physical pain and social rejection, a finding that explains the common theory that being spurned or breaking up with a lover really "hurts". In a landmark research, psychologists at the University of California, Los Angeles, found that the human body has a gene which connects physical pain sensitivity with social pain sensitivity.The research, published by the Proceedings of the National Academy of Sciences, backs the commonly held theory that rejection "hurts" by showing that a gene regulating the body''s most potent painkillers—mu-opioids—is involved in socially painful experiences too. "Individuals with the rare form of the pain gene, who were shown in previous work to be more sensitive to physical pain, also reported higher levels of rejection sensitivity and showed greater activity in social pain-related regions of the brain when they were excluded," said Prof Naomi Eisenberger, the study co-author.The study indicates that a variation in the mu-opioid receptor gene (OPRM1), often associated with physical pain, is related to how much social pain a person feels in response to social rejection, the Daily Telegraph reported. "These findings suggest that the feeling of being given the cold shoulder by a romantic interest or not being picked for a schoolyard game of basketball may arise from the same circuits," said co-author Baldwin Way.According to Prof Eisenberger, this overlap in the neurobiology of physical and social pain makes perfect sense.
When news like this comes out, I usually like to dig up the original scientific paper so I can study it more thoroughly. If one thing ever holds true, it is that the media does a terrible job of representing scientific findings in a large percentage of their published stories. On top of that, the media never make it easy to find the original article from which they cite their information—they instead leave puzzle pieces for you to fit together. Maybe I ask too much. Either way, after some searching, I found the original, which can be downloaded here. The paper's abstract delves a little deeper into the mechanisms connecting emotional and physical pain associated with a broken heart:
Scientific understanding of social pain—the hurt feelings resulting from social rejection, separation, or loss—has been facilitated by the hypothesis that such feelings arise, in part, from some of the same neural and neurochemical systems that generate the unpleasant feelings resulting from physical pain. Accordingly, in animals, the painkiller morphine not only alleviates the distress of physical pain, but also the distress of social separation. Because morphine acts on the μ-opioid receptor, we examined whether variation in the μ-opioid receptor gene (OPRM1), as measured by the functional A118G polymorphism, was associated with individual differences in rejection sensitivity. Participants (n = 122) completed a self-report inventory of dispositional sensitivity to social rejection and a subsample (n = 31) completed a functional MRI session in which they were rejected from an online ball-tossing game played with two supposed others. The A118G polymorphism was associated with dispositional sensitivity to rejection in the entire sample and in the fMRI subsample. Consistent with these results, G allele carriers showed greater reactivity to social rejection in neural regions previously shown to be involved in processing social pain as well as the unpleasantness of physical pain, particularly the dorsal anterior cingulate cortex (dACC) and anterior insula. Furthermore, dACC activity mediated the relationship between the A118G polymorphism and dispositional sensitivity to rejection, suggesting that this is a critical site for μ-opioid-related influence on social pain. Taken together, these data suggest that the A118G polymorphism specifically, and the μ-opioid receptor more generally, are involved in social pain in addition to physical pain.
In order to practise what I preach, here is the citation:
Way, Baldwin M., Shelley E. Taylor, and Naomi I. Eisenberger. "Variation in the μ-opioid receptor gene (OPRM1) is associated with dispositional and neural sensitivity to social rejection." Proceedings of the National Academy of Sciences (August 2009).