The amygdala, a small deep brain structure involved in behavioral processing through interactions with other brain regions, has garnered increased attention in recent years in relation to pain processing. As pain is a multidimensional experience that encompasses physical sensation, affect, and cognition, the amygdala is well suited to play a part in this process. Multiple neuroimaging studies of pain in humans have reported activation in the amygdala. Here we summarize these studies by performing a coordinate-based meta-analysis within experimentally induced and clinical pain studies using an activation likelihood estimate analysis. The results are presented in relation to locations of peak activation within and outside of amygdala subregions. The majority of studies identified coordinates consistent with human amygdala cytoarchitecture indicating reproducibility in neuroanatomical labeling across labs, analysis methods, and imaging modalities. Differences were noted between healthy and clinical pain studies: in clinical pain studies, peak activation was located in the laterobasal region, suggestive of the cognitive-affective overlay present among individuals suffering from chronic pain; while the less understood superficial region of the amygdala was prominent among experimental pain studies. Taken together, these findings suggest several important directions for further research exploring the amygdala’s role in pain processing.
The aim of the study was to investigate the relationship between affective state, pain, and coping in hospitalized women with rheumatoid arthritis, including both between- and within-person perspectives.
Participants were 95 female patients between 24 and 82 years of age (M = 50.91; SD = 13.80). For three consecutive days, they rated each night their state affect (positive and negative), pain level, and coping strategies (emotion-, problem- and meaning-focused ones). Relations among variables were tested with a multilevel approach with time included as a covariate.
Within-person meaning-focused coping suppressed the negative pain effect on emotional state, but only for positive affect (Sobel’s z = 2.07, p = .04). Moderators of the pain–affect relationship were between-person differences in pain level (B = −.23, SE = .08, t = −2.884, p = .004) and in meaning-focused coping (B = −.63, SE = .20, t = −2.097, p = .04). Specifically, suppression was significant only for patients who reported lower than sample average pain levels and for patients who reported lower than sample average use of meaning-focused strategies.
Findings indicated that meaning-focused coping can be a crucial strategy for keeping daily positive affect in the face of chronic pain and how this effect is modified by interindividual differences. Even if restricted to the specific context, it may inform an intervention for hospitalized women with rheumatoid arthritis.
Mindfulness-based stress reduction (MBSR) is a structured 8-week group program teaching mindfulness meditation and mindful yoga exercises. MBSR aims to help participants develop nonjudgmental awareness of moment-to-moment experience. Fibromyalgia is a clinical syndrome with chronic pain, fatigue, and insomnia as major symptoms. Efficacy of MBSR for enhanced well-being of fibromyalgia patients was investigated in a 3-armed trial, which was a follow-up to an earlier quasi-randomized investigation. A total of 177 female patients were randomized to one of the following: (1) MBSR, (2) an active control procedure controlling for nonspecific effects of MBSR, or (3) a wait list. The major outcome was health-related quality of life (HRQoL) 2 months post-treatment. Secondary outcomes were disorder-specific quality of life, depression, pain, anxiety, somatic complaints, and a proposed index of mindfulness. Of the patients, 82% completed the study. There were no significant differences between groups on primary outcome, but patients overall improved in HRQoL at short-term follow-up (P=0.004). Post hoc analyses showed that only MBSR manifested a significant pre-to-post-intervention improvement in HRQoL (P=0.02). Furthermore, multivariate analysis of secondary measures indicated modest benefits for MBSR patients. MBSR yielded significant pre-to-post-intervention improvements in 6 of 8 secondary outcome variables, the active control in 3, and the wait list in 2. In conclusion, primary outcome analyses did not support the efficacy of MBSR in fibromyalgia, although patients in the MBSR arm appeared to benefit most. Effect sizes were small compared to the earlier, quasi-randomized investigation. Several methodological aspects are discussed, e.g., patient burden, treatment preference and motivation, that may provide explanations for differences. In a 3-armed randomized controlled trial in female patients suffering from fibromyalgia, patients benefited modestly from a mindfulness-based stress reduction intervention.