Neural correlates of up-regulating positive emotions in fMRI and their link to affect in daily life

Better together: A systematic review of studies combining magnetic resonance imaging with ecological momentary assessment

Social neuroscientists often use magnetic resonance imaging (MRI) to understand the relationship between social experiences and their neural substrates. Although MRI is a powerful method, it has several limitations in the study of social experiences, first and foremost its low ecological validity. To address this limitation, researchers have conducted multimethod studies combining MRI with Ecological Momentary Assessment (EMA). However, there are no existing recommendations for best practices for conducting and reporting such studies. To address the absence of standards in the field, we conducted a systematic review of papers that combined the methods. A systematic search of peer-reviewed papers resulted in a pool of 11,558 articles. Inclusion criteria were studies in which participants completed (a) Structural or functional MRI and (b) an EMA protocol that included self-report. Seventy-one papers met inclusion criteria. The following review compares these studies based on several key parameters (e.g., sample size) with the aim of determining feasibility and current standards for design and reporting in the field. The review concludes with recommendations for future research. A special focus is given to the ways in which the two methods were combined analytically and suggestions for novel computational methods that could further advance the field of social neuroscience.

Corticolimbic structural connectivity encapsulates real-world emotional reactivity and happiness

Emotional reactivity to everyday events predicts happiness, but the neural circuits underlying this relationship remain incompletely understood. Here, we combined experience sampling methods and diffusion magnetic resonance imaging to examine the association among corticolimbic structural connectivity, real-world emotional reactivity and daily experiences of happiness from 79 young adults (35 females). Participants recorded momentary assessments of emotional and happiness experiences five times a day for a week, approximately 2 weeks after brain scanning. Model-based emotional reactivity scores, which index the degree to which moment-to-moment affective state varies with the occurrence of positive or negative events, were computed. Results showed that stronger microstructural integrity of the uncinate fasciculus and the external capsule was associated with both greater positive and negative emotional reactivity scores. The relationship between these fiber tracts and experienced happiness was explained by emotional reactivity. Importantly, this indirect effect was observed for emotional reactivity to positive but not negative real-world events. Our findings suggest that the corticolimbic circuits supporting socioemotional functions are associated with emotional reactivity and happiness in the real world.

Short-Term Head-Out Whole-Body Cold-Water Immersion Facilitates Positive Affect and Increases Interaction between Large-Scale Brain Networks

An emerging body of evidence indicates that short-term immersion in cold water facilitates positive affect and reduces negative affect. However, the neural mechanisms underlying these effects remain largely unknown. For the first time, we employed functional magnetic resonance imaging (fMRI) to identify topological clusters of networks coupled with behavioural changes in positive and negative affect after a 5 min cold-water immersion. Perceived changes in positive affect were associated with feeling more active, alert, attentive, proud, and inspired, whilst changes in negative affect reflected reductions in distress and nervousness. The increase in positive affect was supported by a unique component of interacting networks, including the medial prefrontal node of the default mode network, a posterior parietal node of the frontoparietal network, and anterior cingulate and rostral prefrontal parts of the salience network and visual lateral network. This component emerged as a result of a focal effect confined to few connections. Changes in negative affect were associated with a distributed component of interacting networks at a reduced threshold. Affective changes after cold-water immersion occurred independently, supporting the bivalence model of affective processing. Interactions between large-scale networks linked to positive affect indicated the integrative effects of cold-water immersion on brain functioning.

Investigating adult age differences in real-life empathy, prosociality, and well-being using experience sampling

While the importance of social affect and cognition is indisputable throughout the adult lifespan, findings of how empathy and prosociality develop and interact across adulthood are mixed and real-life data are scarce. Research using ecological momentary assessment recently demonstrated that adults commonly experience empathy in daily life. Furthermore, experiencing empathy was linked to higher prosocial behavior and subjective well-being. However, to date, it is not clear whether there are adult age differences in daily empathy and daily prosociality and whether age moderates the relationship between empathy and prosociality across adulthood. Here we analyzed experience-sampling data collected from participants across the adult lifespan to study age effects on empathy, prosocial behavior, and well-being under real-life circumstances. Linear and quadratic age effects were found for the experience of empathy, with increased empathy across the three younger age groups (18 to 45 years) and a slight decrease in the oldest group (55 years and older). Neither prosocial behavior nor well-being showed significant age-related differences. We discuss these findings with respect to (partially discrepant) results derived from lab-based and traditional survey studies. We conclude that studies linking in-lab experiments with real-life experience-sampling may be a promising venue for future lifespan studies.

Widespread Pressure Delivered by a Weighted Blanket Reduces Chronic Pain: A Randomized Controlled Trial

Pleasant sensation is an underexplored avenue for modulation of chronic pain. Deeper pressure is perceived as pleasant and calming, and can improve sleep. Although pressure can reduce acute pain, its effect on chronic pain is poorly characterized. The current remote, double-blind, randomized controlled trial tested the hypothesis that wearing a heavy weighted blanket - providing widespread pressure to the body - relative to a light weighted blanket would reduce ratings of chronic pain, mediated by improvements in anxiety and sleep. Ninety-four adults with chronic pain were randomized to wear a 15-lb. (heavy) or 5-lb. (light) weighted blanket during a brief trial and overnight for one week. Measures of anxiety and chronic pain were collected pre- and post-intervention, and ratings of pain intensity, anxiety, and sleep were collected daily. After controlling for expectations and trait anxiety, the heavy weighted blanket produced significantly greater reductions in broad perceptions of chronic pain than the light weighted blanket (Cohen's f = .19, CI [-1.97, -.91]). This effect was stronger in individuals with high trait anxiety (P = .02). However, weighted blankets did not alter pain intensity ratings. Pain reductions were not mediated by anxiety or sleep. Given that the heavy weighted blanket was associated with greater modulation of affective versus sensory aspects of chronic pain, we propose that the observed reductions are due to interoceptive and social/affective effects of deeper pressure. Overall, we demonstrate that widespread pressure from a weighted blanket can reduce the severity of chronic pain, offering an accessible, home-based tool for chronic pain. The study purpose, targeted condition, study design, and primary and secondary outcomes were pre-registered in ClinicalTrials.gov (NCT04447885: "Weighted Blankets and Chronic Pain"). Perspective: This randomized-controlled trial showed that a 15-lb weighted blanket produced significantly greater reductions in broad perceptions of chronic pain relative to a 5-lb weighted blanket, particularly in highly anxious individuals. These findings are relevant to patients and providers seeking home-based, nondrug therapies for chronic pain relief.

The regulatory roles of progesterone and estradiol on emotion processing in women

Emotion processing is known to interact with memory. Ovarian steroid hormones, such as progesterone and estradiol, modulate emotion processing and memory. However, it is unclear how these hormones influence brain activity when emotion processing is integrated with working memory (WM). Therefore, the objective of this study was to examine the relationship between endogenous hormonal concentration and brain activity during emotion processing in the context of a WM n-back task in 74 young women using functional magnetic resonance imaging (fMRI). Results show that positive emotion processing activates reward-related areas, such as the caudate and putamen, whereas negative emotion processing activates a corticolimbic network, including the amygdala and hippocampus. Furthermore, our findings provide evidence that progesterone modulates more bottom-up brain activation during both positive and negative emotion processing, whereas estradiol activates lateralized, top-down regulation. These findings provide insight on the neural correlates of emotion processing during an n-back task in young women and highlight how important it is to consider women's endogenous hormonal concentration in neurobiological and cognition research.