Enhanced corticospinal response to observed pain in pain synesthetes

Observing noxious injury to another’s hand is known to induce corticospinal inhibition that can be measured in the observer’s corresponding muscle. Here, we investigated whether acquired pain synesthetes, individuals who experience actual pain when observing injury to another, demonstrate less corticospinal inhibition than do controls during pain observation, as a potential mechanism for the experience of vicarious pain. We recorded motor-evoked potentials (MEPs) induced at two time points through transcranial magnetic stimulation while participants observed videos of a hand at rest, a hypodermic needle penetrating the skin, a Q-tip touching the skin, and a hypodermic needle penetrating an apple. We compared MEPs in three groups: 7 amputees who experience pain synesthesia, 11 nonsynesthete amputees who experience phantom limb pain, and 10 healthy controls. Results indicated that the pain synesthete group demonstrated significantly enhanced MEP response to the needle penetrating the hand, relative to the needle not having yet penetrated the hand, as compared with controls. This effect was not observed exclusively in the same muscle where noxious stimulation was applied. We speculate that our findings reflect a generalized response to pain observation arising from hyperactivity of motor mirror neurons not involved in direct one-to-one simulation but, rather, in the representation of another’s experience.     

Prior exposure to extreme pain alters neural response to pain in others

In the extant literature examining the brain mechanisms implicated in pain perception, researchers have theorized that the overlapping responses to pain in the self and in others mark the human capacity for empathy. Here we investigated how prior exposure to extreme pain affects pain perception, by assessing the dynamics of pain processing in veterans who were previously exposed to severe injury. Forty-three participants (28 pain-exposed and 15 controls) underwent whole-head magnetoencephalography (MEG) while viewing photographs of limbs in painful and nonpainful (neutral) conditions. Among controls, an early (0–220 ms) “pain effect” in the posterior cingulate and sensorimotor cortices, and a later (760–900 ms) “pain effect” in the posterior cingulate cortex, superior temporal gyrus/insula, and fusiform gyrus were found, indicated by enhanced alpha suppression to the pain versus nonpain conditions. Importantly, pain-exposed participants exhibited an atypical pain response in the posterior cingulate cortex, indicated by a normative response to pain, but no pain-to-no-pain differentiation. This may suggest that individuals exposed to extreme pain may perceive neutral stimuli as potentially threatening. Our findings demonstrate alterations in pain perception following extreme pain exposure, chart the sequence from automatic to evaluative pain processing, and emphasize the importance of considering past experiences in studying the neural response to others’ states.     

Sleep and the affective response to stress and pain.

OBJECTIVE: The current study examined sleep disturbance (i.e., sleep duration, sleep quality) as a correlate of stress reactivity and pain reactivity. DESIGN AND OUTCOME MEASURES: An ecological momentary assessment design was used to evaluate the psychosocial functioning of men and women with fibromyalgia or rheumatoid arthritis (N=49). Participants recorded numeric ratings of pain, the occurrence of a stressful event, as well as positive and negative affect 7 times throughout the day for 2 consecutive days. In addition, participants reported on their sleep duration and sleep quality each morning. RESULTS: Sleep disruption was not found to be an independent predictor of affect. However, sleep was found to buffer the relationship between stress and negative affect and the relationship between pain and both positive and negative affect. CONCLUSION: These results are consistent with a model in which good-quality sleep acts as a biobehavioral resource that minimizes allostatic load.     

Personality disorders and response to outpatient treatment of chronic pain

As part of a comprehensive interdisciplinary evaluation conducted prior to participation in an outpatient chronic pain treatment program, the psychological status of 101 persons was assessed. The majority of participants was found to have a form of personality disorder, determined by conservative cutoff scores applied to their Millon Clinical Multiaxial Inventory (MCMI) profiles. DSM-III-R Cluster C disorders (i.e., Avoidant, Dependent, Obsessive-Compulsive, and Passive-Aggressive) were overrepresented in this sample. Subsequent analyses revealed that personality disorders were related to higher levels of self-reported distress and pain at both the beginning and the end of outpatient treatment. Differential responses to treatment were observed on self-report measures; however, few relations were found between personality disorder and physical therapist ratings of impairment and improvement. Implications for the assessment of personality disorders in outpatient pain treatment programs are discussed and appropriate intervention strategies are considered.     

Psychological and Neuroendocrine Reactivity to Ostracism

This study used the ostracism detection theory to investigate how ostracism impacts individuals in two ways: (1) immediate poststressor needs, mood, ruminative thoughts, and desire to affiliate, and (2) short‐term affective and cortisol reactivity. A total of 58 college students were randomly assigned to the inclusion or ostracism conditions of Cyberball, a virtual ball‐tossing game. Immediately following the experimental manipulation, ostracized participants reported more thwarted psychological need states, more negative mood, and fewer positive ruminative thoughts, relative to their included counterparts. Ostracized participants reported a greater interest in affiliating with others in online or in‐person settings. In the short‐term, ostracized males reported more hostility than included males, although the scores were within expected norms for most males. There was no relation between Cyberball condition and gender across time for depression, anxiety, or positive affect. Approximately 20 min after the onset of the stressor, women in the luteal phase and women taking oral contraceptives in the ostracized group displayed higher cortisol than their counterparts in the included group. Relative to baseline, however, cortisol did not reliably increase after the onset of the stressor. Ostracized females taking oral contraceptives showed the greatest decline in cortisol, compared to included oral contraceptive users. Overall, results suggest that most of the negative effects of ostracism are immediate and limited to psychological, not neuroendocrine, responses.     

Mothers' facial expressions of pain and fear and infants' pain response during immunization

The goal of the current study was to examine the relationship between mothers' spontaneous facial expressions of pain and fear immediately preceding their infants' immunizations and infants' facial expressions of pain immediately following immunizations. Infants' observations of mothers' faces prior to immunization also were examined to explore whether these observations moderated the effect of mothers' facial expressions on infant pain. The final sample included 58 mothers and their infants. Video data were used to code maternal facial expressions, infants' observations, and infants' expressions of pain. Infants who observed their mothers' faces had mothers who expressed significantly more fear pre‐needle. Furthermore, mothers' facial expressions of mild fear pre‐needle were associated with lower levels of infants' pain expression post‐needle. A regression analysis confirmed maternal facial expressions of mild fear pre‐needle as the strongest predictor of infant pain post‐needle after controlling for infants' observations of mothers' faces. Mothers' subtle facial expressions of fear may indicate a relationship history of empathic caregiving that functions to support infants' abilities to regulate distress following painful procedures. Interventions aimed at improving caregiver sensitivity to infants' emotional cues may prove beneficial to infants in pain. Future directions in research are discussed.     

Narcissism and Cardiovascular Reactivity to Rejection Imagery1

This study examined the interactive effects of imagined rejection and narcissism on cardiovascular reactivity (CVR). Participants completed measures of overt narcissism (Narcissistic Personality Inventory, NPI; Raskin & Hall, 1979 ), overt–covert narcissism ( Margolis & Thomas, 1980 ), and trait self‐esteem. They then imagined 2 scenarios culminating in either interpersonal acceptance or rejection. Systolic (SBP) and diastolic blood pressure (DBP) and heart rate (HR) were assessed before, during, and after the imagery. Overt–covert narcissism was positively associated with task increases in SBP and DBP and recovery elevation of HR following rejection, but not acceptance. Similar effects on SBP were found for the Entitlement/Exploitativeness dimension of the NPI. Lower self‐esteem predicted greater task increases in SBP, DBP, and HR across conditions. Implications for health are discussed.     

Reactivity and regulation in children prenatally exposed to cocaine

Children prenatally exposed to cocaine may be at elevated risk for adjustment problems in early development because of greater reactivity and reduced regulation during challenging tasks. Few studies have examined whether cocaine-exposed children show such difficulties during the preschool years, a period marked by increased social and cognitive demands and by rapid changes in reactivity and regulation. The authors addressed this question by examining frustration reactivity and regulation of behavior during a problem-solving task in cocaine-exposed and -unexposed preschoolers. Participants were 174 4.5-year-olds (M age = 4.55 years, SD = 0.09). Frustration reactivity was measured as latency to show frustration and number of disruptive behaviors, whereas regulation was measured as latency to approach and attempt the problem-solving task and number of problem-solving behaviors. Results indicated that cocaine-exposed children took longer to attempt the problem-solving task but that cocaine-exposed boys showed the most difficulties: They were quicker to express frustration and were more disruptive. Effect sizes were relatively small, suggesting both resilience and vulnerabilities.     

Reactivity of Tic Observation Procedures to Situation and Setting

Tic frequency was assessed and compared across home and clinic as well as three experimentally-manipulated situations in order to assess the phenomenon of tic reactivity. Forty-three youngsters with chronic tic disorder recruited from two geographically-distinct sites were videotaped over three weekly laboratory visits under each of the following conditions: (1) alone/camera present, (2) other present/camera present, and (3) alone/camera hidden. Contrary to expectation, more tics were observed during overt as compared to covert observation, while the presence of another person had no overall impact on tic expression. Mean tic counts obtained from clinic observation did not significantly differ from those obtained at home collected either one day before or after. Tic frequency counts were remarkably stable over the three weekly assessments both at home and clinic. Study findings are consistent with past observations that tic expression can be influenced by environmental factors and suggest the stability of tic frequency may exhibit greater temporal and setting stability than previously thought. The clinical and research implications of these results are discussed.     

Current Concerns and Electrodermal Reactivity: Responses to Words and Thoughts

ABSTRACT Previous research has found that subjects rate words that are closely related to their current concerns as affectively more arousing than other words. This investigation inquires whether a similar relationship occurs when arousal is measured electrodermally, and whether nonspecific (spontaneous) electrodermal activity is associated with self-generated thoughts about current concerns. In the first experiment, subjects listened to audiotaped sequences of three-word clusters associated with previously measured own current concerns or with concerns of others. Mean skin conductance responses were significantly larger for clusters related to subjects' own concerns than for those related to others' concerns, although many subjects contributing to this effect showed some awareness of the hypothesis. In the second experiment, thoughts that accompanied nonspecific skin conductance responses received significantly higher self-ratings for concern-relatedness and arousal than thoughts that occurred during electrodermal inactivity. In Experiment 3, they were rated higher for current-concern content and anxiety and lower for mental imagery and dormant-concern content than thoughts during electrodermal inactivity.     

Children's Emotional Reactivity to Interadult Nonverbal Conflict Expressions

The authors investigated children's responses to nonverbal expressions of conflict. Reactions of 3 groups of children (ranging in age from 6 to 16 years) to multiple forms of nonverbal conflict behaviors expressed in videotaped simulations of interadult disputes were examined. Results indicated that children make few discriminations between different forms of nonverbal conflict behaviors and that their reactions to nonverbal conflict are similar to their reactions to verbal conflict. Adults' expressions of fear elicited the most negative emotional responses from children, suggesting that children react to the meaning of conflict expressions and that expressions of fear may represent the greatest emotional security risks to children. Implications of these results for a theoretical model of the effects of forms of marital conflict on children are discussed (P. T. Davies & E. M. Cummings, 1994).     

Psychophysiological Reactivity to Abuse-Related Stimuli in Sexually Revictimized Women

Prior research shows discrepant findings in relation to psychophysiological reactivity to threat in women with histories of sexual victimization. Women ages 18 to 22 (N?=?123) with histories of sexual abuse were categorized into child sexual abuse (CSA), adult sexual victimization, revictimization, or nonvictimization groups. Low- and high-frequency heart rate variability were measured at baseline and during an Emotional Stroop task of abuse-related words. Revictimized women showed a significant decrease from baseline to task in both parasympathetic and sympathetic measures when compared to the CSA group. The CSA group demonstrated chronic sympathetic activation at both baseline and task, relative to the revictimization group. Groups did not differ on performance (i.e., reaction time) on the Emotional Stroop task (i.e., more threatening stimuli, slower performance). Cardiovascular responses reported might point to biological reactivity patterns needed for women with a history of sexual abuse to cope with abuse-related stimuli.     

Suffering for science: the effects of implicit social demands on response to experimentally induced pain

In two experiments subjects rated their pain during baseline trials of cold pressor and finger pressure pain. After various instructional treatments, they were posttested with these same stimuli. As in previous studies, we found in both experiments that coping suggestions significantly reduced reported pain. Experiment 1, however, demonstrated that subjects often refrained from using available cognitive coping strategies to reduce pain unless they had been given explicit permission to do so. Experiment 2 replicated this finding and also showed that explicit permission to "do whatever you can to reduce pain" was as effective as a coping suggestion in decreasing reported pain. These findings indicate that subjects' interpretation of what is appropriate responding in the test situation determines how they choose to cope with the painful stimulation. Thus standard experimental procedures for assessing baseline levels of pain implicitly lead subjects to refrain from coping and thereby tend to underestimate their ability to control pain. Moreover, suggestions and other instructional techniques for coping with pain may produce much of their effect not by teaching subjects new coping skills but instead by giving them permission to use already available coping strategies.