Facial expression is widely used as a measure of pain in infants; whether nonhuman animals display such pain expressions has never been systematically assessed. We developed the mouse grimace scale (MGS), a standardized behavioral coding system with high accuracy and reliability; assays involving noxious stimuli of moderate duration are accompanied by facial expressions of pain. This measure of spontaneously emitted pain may provide insight into the subjective pain experience of mice.

Empathy is thought to be unique to higher primates, possibly to humans alone. We report the modulation of pain sensitivity in mice produced solely by exposure to their cagemates, but not to strangers, in pain. Mice tested in dyads and given an identical noxious stimulus displayed increased pain behaviors with statistically greater co-occurrence, effects dependent on visual observation. When familiar mice were given noxious stimuli of different intensities, their pain behavior was influenced by their neighbor's status bidirectionally. Finally, observation of a cagemate in pain altered pain sensitivity of an entirely different modality, suggesting that nociceptive mechanisms in general are sensitized.

Because multiple symptoms associated with “sickness behavior” have a negative impact on functional status and quality of life, increased information on the mechanisms that underlie inter-individual variability in this symptom experience is needed. The purposes of this study were to determine: if distinct classes of individuals could be identified based on their experience with pain, fatigue, sleep disturbance, and depression; if these classes differed on demographic and clinical characteristics; and if variations in pro- and anti- inflammatory cytokine genes were associated with latent class membership. Self-report measures of pain, fatigue, sleep disturbance, and depression were completed by 168 oncology outpatients and 85 family caregivers (FCs). Using latent class profile analysis (LCPA), three relatively distinct classes were identified: those who reported low depression and low pain (83%), those who reported high depression and low pain (4.7%), and those who reported high levels of all four symptoms (12.3%). The minor allele of IL4 rs2243248 was associated with membership in the “All high” class along with younger age, being White, being a patient (versus a FC), having a lower functional status score, and having a higher number of comorbid conditions. Findings suggest that LPCA can be used to differentiate distinct phenotypes based on a symptom cluster associated with sickness behavior. Identification of distinct phenotypes provides new evidence for the role of IL4 in the modulation of a sickness behavior symptom cluster in oncology patients and their FCs.

Study purposes were to determine the prevalence of persistent pain in the breast; characterize distinct persistent pain classes using growth mixture modeling, and evaluate for differences among these pain classes in demographic, preoperative, intraoperative, and postoperative characteristics. In addition, differences in the severity of common symptoms and quality of life outcomes measured prior to surgery, among the pain classes, were evaluated. Patients (n=398) were recruited prior to surgery and followed for six months. Using growth mixture modeling, patients were classified into no (31.7%), mild (43.4%), moderate (13.3%), and severe (11.6%) pain groups based on ratings of worst breast pain. Differences in a number of demographic, preoperative, intraoperative, and postoperative characteristics differentiated among the pain classes. In addition, patients in the moderate and severe pain classes reported higher preoperative levels of depression, anxiety, and sleep disturbance than the no pain class. Findings suggest that approximately 25% of women experience significant and persistent levels of breast pain in the first six months following breast cancer surgery.

The relationship between psychopathic traits and the perception of nonverbal communication, including facial expressions and body language, is investigated. Participants include 59 prison inmates and 60 community members. Psychopathic traits among inmates are measured using the Psychopathy Checklist-Revised (PCL-R) and Levenson's Self Report Psychopathy Scale. Participants categorize the emotion of posed facial photographs and rate intensity of emotion. They view videotaped interactions of a confederate and a target individual and rate assertiveness using the Rathus Assertiveness Scale. There is a trend for the PCL-R to be positively correlated with the inmates' accuracy of emotional intensity ratings. Psychopathic traits are also positively associated with the accuracy of assertiveness ratings. P sychopathy is characterized by irresponsibility, impulsivity, antisocial behavior, an inability to learn from punishment, and a lack of long-term goals (Cleckley, 1941). The key characteristics of psychopathy are measured in the Psychopathy Checklist-Revised (PCL-R; Hare, 1991). The 20-item instrument was originally thought to consist of two factors: (a) affective and interpersonal symptoms, such as reduced affect, lack of empathy, manipulativeness, and lack of remorse, and (b) symptoms of social deviance, including a lack of long-term goals and behavioral problems. Patrick (1994) aptly relabeled these factors emotional detachment and antisocial behavior. Other research has suggested the existence of three factors (Cooke & Michie, 2001), and at the point of the last revision of the PCL-R, factor analyses indicate that there are four facets (subsumed under the two factors given above; Hare, 2003): interpersonal, affective, lifestyle, and antisocial. The interpersonal and affective facets make up the interpersonal/affective component (Factor 1), and the lifestyle and antisocial facets make up the social deviance component (Factor 2).Because affect and empathy are typically attenuated in psychopaths, Cleckley (1941) suggested that psychopaths suffer from emotional poverty, a view that is shared by others 531