Empathy for another's physical pain has been demonstrated in humans [1] and mice [2]; in both species, empathy is stronger between familiars. Stress levels in stranger dyads are higher than in cagemate dyads or isolated mice [2, 3], suggesting that stress might be responsible for the absence of empathy for the pain of strangers. We show here that blockade of glucocorticoid synthesis or receptors for adrenal stress hormones elicits the expression of emotional contagion (a form of empathy) in strangers of both species. Mice and undergraduates were tested for sensitivity to noxious stimulation alone and/or together (dyads). In familiar, but not stranger, pairs, dyadic testing was associated with increased pain behaviors or ratings compared to isolated testing. Pharmacological blockade of glucocorticoid synthesis or glucocorticoid and mineralocorticoid receptors enabled the expression of emotional contagion of pain in mouse and human stranger dyads, as did a shared gaming experience (the video game Rock Band) in human strangers. Our results demonstrate that emotional contagion is prevented, in an evolutionarily conserved manner, by the stress of a social interaction with an unfamiliar conspecific and can be evoked by blocking the endocrine stress response.

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Chronic pain is a highly prevalent and poorly managed human health problem. We used microarray-based expression genomics in 25 inbred mouse strains to identify dorsal root ganglion (DRG)-expressed genetic contributors to mechanical allodynia, a prominent symptom of chronic pain. We identified expression levels of Chrna6, which encodes the α6 subunit of the nicotinic acetylcholine receptor (nAChR), as highly associated with allodynia. We confirmed the importance of α6* (i.e., α6-containing) nAChRs by analyzing both gain- and loss-of-function mutants. We find that mechanical allodynia associated with neuropathic and inflammatory injuries is significantly altered in α6* mutants, and that α6* but not α4* nicotinic receptors are absolutely required for peripheral and/or spinal nicotine analgesia. Furthermore, we show that Chrna6’s role in analgesia is at least partially due to direct interaction and cross-inhibition of α6* nAChRs with P2X2/3 receptors in DRG nociceptors. Finally, we establish relevance of our results to humans by the observation of genetic association in patients suffering from chronic postsurgical pain and temporomandibular pain.

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Background In contrast to standard donor retention strategies (e.g., mailings, phone calls, text messages), we developed a brief telephone interview, based on motivational interviewing principles, which encourages blood donors to reflect upon their unique motivators and barriers for giving. The present study examined the effect of this motivational interview, combined with action and coping plan components, on blood donor motivations. Study Design and Methods The design was to randomly assign blood donors to receive either a telephone-delivered motivational interview with action and coping plan components or a control call approximately six weeks after their most recent donation. Participants completed a series of surveys related to donation motivation approximately 3 weeks before telephone contact (pre-call baseline) and then repeated these surveys approximately one week after telephone contact (post-call). Results The sample was 63% female, included a majority (52.6%) first-time blood donors, and had a mean age of 30.0 years (SD = 11.7). A series of ANOVAs revealed that, relative to controls (n=244), donors in the motivational interview group (n=254) had significantly larger increases in motivational autonomy (p=0.001), affective attitude (p=0.004), self-efficacy (p=0.03), anticipated regret (p=0.001), and intention (p=<0.001), as well as larger decreases in donation anxiety (p=0.01), from pre-call baseline to post-call assessment. Conclusion This study supports motivational interviewing with action and coping planning as a novel strategy to promote key contributors to donor motivation.