PROJECT SUMMARY
Reduced positive affect is a core symptom of many stress-related psychiatric disorders, including depression
and PTSD. Critically, positive affect is not simply the inverse of negative affect, and clinicians struggle to increase
positive affect: Antidepressant and psychotherapeutic interventions often reduce depressed mood but are
ineffective at increasing positive affect. And yet, qualitative studies of patients themselves indicate that a ‘full
recovery’ requires increasing positive emotion, even when other depressive symptoms have subsided.
Despite the critical role of positive emotion, very limited work has identified effective interventions to increase
real-world positive affect to improve mental health. Guided by preclinical work, we recently discovered that
positive affect is increased when going to a greater number of varied locations (“experiential diversity”).
Moreover, the association between experiential diversity and positive affect appears to be supported specifically
by functional connectivity between the hippocampus and nucleus accumbens–a stress susceptible circuit
responsible for assigning reward value to novelty. This finding suggests that increasing experiential diversity
may be a plausible real-world intervention to increase positive affect by strengthening specific neural circuits.
Leveraging a strong team with complimentary expertise in mobile tracking, resting state fMRI, treatment
development, and affective science, this R01 application will expand these initial findings in a large,
demographically representative sample encompassing a range of anhedonia severity (from asymptomatic to
severe) collecting geolocation (GPS), experience sampling of emotion, and functional MRI to, (1) precisely
delineate the specific geospatial features of experiential diversity most strongly linked to increases in momentary
(EMA measured) positive affect (e.g., neighborhoods one has never visited, green spaces, beach/ocean); (2)
determine whether individuals with higher levels of anhedonia have similar affective benefits from these types of
experiential diversity as individuals with lower experiential diversity; (3) determine the neural network circuit
mechanisms supporting associations between experiential diversity and affect as a function of anhedonia; and
(4) in an independent sample, experimentally induce experiential diversity to determine if it causes increased
positive affect. Results from this application will help to define the neural mechanisms by which exploration and
experiential diversity predict increases in positive affect and will yield actionable real-world interventions for a
clinical trial to improve positive affect in those with heightened anhedonia.