Jennifer K. MacCormack, PhD - US grants

PROJECT SUMMARY Many older adults experience positive emotional changes as they age, including fewer negative emotions, greater mood stability, and greater ease regulating feelings. However, research suggests that these positive changes may occur in part because older adults? autonomic nervous systems are less reactive to emotional stimuli (i.e., autonomic reactivity) and because older adults find it increasingly hard to pick up on internal bodily reactions in the first place (i.e., interoception). These embodied changes in turn make it easier for older adults to prioritize neutral and positive experiences and regulate negative feelings. But it remains unclear why older adults experience these changes in autonomic reactivity and interoception in the first place. The present project tests the hypothesis that age-related changes in the brain?s representation of autonomic nervous system activity and interoception may actually help explain the differences between older vs. younger adults? emotional experiences and regulation. Two studies address this possibility. Study 1 uses the increased statistical power of meta-analysis to summarize all functional neuroimaging literature on older adult emotion and test for age differences in neural activation and connectivity in regions supporting autonomic reactivity and interoception. In Study 2, older and younger adults complete a laboratory visit and functional magnetic resonance imaging (fMRI) visit. During the lab visit, emotion is manipulated via a stress induction to measure age differences in autonomic reactivity and interoception. In the fMRI scanner, emotion is manipulated via an image-based emotion induction to assess age differences in brain activation and connectivity. In turn, autonomic reactivity, interoception, and measured neural activations and connectivity are correlated and used to predict differences in older vs. younger adults? emotional experiences and ability to regulate their feelings. Expected results are that older adults will exhibit decreased neural activity and connectivity in the brain regions involved in autonomic reactivity and interoception (i.e., the core limbic and paralimbic networks) relative to young adults, and that these neural differences will explain older adults? declines in autonomic reactivity and interoception, as well as reduced negative emotions and easier emotion regulation during the emotion inductions. These studies are the first to examine age-related differences in how older adults? brains represent the embodied aspects of emotion. Ultimately, this project can offer crucial insights into aging health and wellbeing, delineating further biological pathways by which emotions contribute to physical and mental health across the lifespan.