The role of the right temporoparietal junction in the elicitation of vicarious experiences and detection accuracy while observing pain and touch.

This study investigated the effects of observing pain and touch in others upon vicarious somatosensory experiences and the detection of subtle somatosensory stimuli. Furthermore, transcranial direct current stimulation (tDCS) was used to assess the role of the right temporoparietal junction (rTPJ), as this brain region has been suggested to be involved in perspective taking and self-other distinction. Undergraduates (N = 22) viewed videos depicting hands being touched, hands being pricked, and control scenes (same approaching movement as in the other video categories but without the painful/touching object), while experiencing vibrotactile stimuli themselves on the left, right, or both hands. Participants reported the location at which they felt a somatosensory stimulus. Vibrotactile stimuli and visual scenes were applied in a congruent or incongruent way. During three separate testing sessions, excitability of the rTPJ was modulated with tDCS (cathodal, anodal, or sham). We calculated the proportion of correct responses and false alarms (i.e., number of trials in which a vicarious somatosensory experience was reported congruent to the site of the visual information). Pain-related scenes facilitated the correct detection of tactile stimuli and augmented the number of vicarious somatosensory experiences compared with observing touch or control videos. Stimulation of the rTPJ had no reliable influence upon detection accuracy or the number of vicarious errors. This study indicates that the observation of pain-related scenes compared to the observation of touch or control videos increases the likelihood that a somatosensory stimulus is detected. Contrary to our expectations, the rTPJ did not modulate detection accuracy.

Vicarious experiences and detection accuracy while observing pain and touch: The effect of perspective taking.

In this study, we investigated the effects of observing pain and touch in others on vicarious somatosensory experiences and the detection of subtle somatosensory stimuli. Furthermore, the effect of taking a first- versus a third-person perspective was investigated. Undergraduates (N = 57) viewed videos depicting hands being pricked (pain), hands being touched by a cotton swab (touch), and control scenes (same approaching movement of a hand as in the other video categories, but without the painful/touching object) while experiencing vibrotactile stimuli themselves on the left, on the right, or on both hands. Participants reported the location at which they felt a somatosensory stimulus. The vibrotactile stimuli and visual scenes were applied in a spatially congruent or incongruent way, and other trials were presented without vibrotactile stimuli. The videos were depicted in first-person perspective and third-person perspective (i.e., the videos were shown upside down). We calculated the proportions of correct responses and false alarms (i.e., numbers of trials on which a vicarious somatosensory experience was reported congruent or incongruent to the site of the visual information). Pain-related scenes facilitated the detection of tactile stimuli and augmented the number of vicarious somatosensory experiences, as compared with observing the touch or control videos. Detection accuracy was higher for videos depicted in first-person perspective than for those in third-person perspective. Perspective had no effect on the number of vicarious somatosensory experiences. This study indicates that somatosensory detection is particularly enhanced during the observation of pain-related scenes, as compared to the observation of touch or control videos. These research findings further demonstrate that perspective taking impacts somatosensory detection, but not the report of vicarious experiences.

Fibromyalgia patients and controls are equally accurate in detecting tactile stimuli while observing another in pain: an experimental study.

This study investigated the effects of observing pain in others upon vicarious somatosensory experiences and the detection of somatosensory stimuli in both fibromyalgia (FM) patients and controls. The putative modulatory role of dispositional empathy, hypervigilance to pain, and central sensitization was examined. FM patients (n = 39) and controls (n = 38) saw videos depicting pain-related (hands being pricked) and non-pain-related scenes, while occasionally experiencing vibrotactile stimuli themselves on the left, right, or both hands. Participants reported the location at which they felt a somatosensory stimulus. Tactile and visual scenes were presented in the same spatial location (congruent; e.g., left-left) or from opposite locations (incongruent; e.g., left-right). We calculated the proportion of correct responses, vicarious somatosensory experiences (i.e., trials on which an illusory somatosensory experience was reported while observing pain-related scenes), and neglect errors (i.e., reporting only the site congruent to the visual pain-related information when both hands had been stimulated). Observing another in pain resulted in an equal numbers of vicarious somatosensory experiences in both groups and facilitated the detection of tactile stimuli, especially during spatially congruent trials. Counter to our expectations, this facilitation was not moderated by group. FM patients made fewer neglect errors. Hypervigilance for pain, dispositional empathy, and central sensitization did not exert a modulatory role. Observing pain facilitates the detection of tactile stimuli in FM patients and controls. Overall, a low incidence of vicarious experiences was observed. Further research is needed to understand the role of attentional body focus in the elicitation of vicarious experiences.

Vicarious pain while observing another in pain: an experimental approach.

OBJECTIVE: This study aimed at developing an experimental paradigm to assess vicarious pain experiences. We further explored the putative moderating role of observer's characteristics such as hypervigilance for pain and dispositional empathy. METHODS: Two experiments are reported using a similar procedure. Undergraduate students were selected based upon whether they reported vicarious pain in daily life, and categorized into a pain responder group or a comparison group. Participants were presented a series of videos showing hands being pricked whilst receiving occasionally pricking (electrocutaneous) stimuli themselves. In congruent trials, pricking and visual stimuli were applied to the same spatial location. In incongruent trials, pricking and visual stimuli were in the opposite spatial location. Participants were required to report on which location they felt a pricking sensation. Of primary interest was the effect of viewing another in pain upon vicarious pain errors, i.e., the number of trials in which an illusionary sensation was reported. Furthermore, we explored the effect of individual differences in hypervigilance to pain, dispositional empathy and the rubber hand illusion (RHI) upon vicarious pain errors. RESULTS: RESULTS of both experiments indicated that the number of vicarious pain errors was overall low. In line with expectations, the number of vicarious pain errors was higher in the pain responder group than in the comparison group. Self-reported hypervigilance for pain lowered the probability of reporting vicarious pain errors in the pain responder group, but dispositional empathy and the RHI did not. CONCLUSION: Our paradigm allows measuring vicarious pain experiences in students. However, the prevalence of vicarious experiences of pain is low, and only a small percentage of participants display the phenomenon. It remains however unknown which variables affect its occurrence.