Project Summary Suicide is much higher in Veterans compared to non-Veterans and thus remains a major health crisis in the VA, but there are few treatments available that directly target core features of suicidal thoughts and behaviors. Rumination is the strong tendency to engage in self-critical repetitive thinking that is often difficult to interrupt and is associated with suicide attempts and the transition from suicidal ideation to intent above and beyond other suicide risk factors. Meta-analyses indicate that abnormalities in brain regions comprising the “default mode network,” which play a role in daydreaming or mind-wandering, contribute to the maintenance of rumination. More specifically, deficits in the medial orbital frontal cortex, which plays a crucial role in inhibition, could allow seemingly innocuous stimuli to become integrated with autobiographical features of the self via the precuneus and the over personalization of negative stimuli leading to rumination, thus highlighting a neural circuit through which rumination may be perpetuated and a potential target for intervention. Functional magnetic resonance imaging studies have provided key insights into the neurobiology of suicide, but has had little direct impact on clinical care thus far. With the advent of real-time functional magnetic resonance imaging neurofeedback, however, there is now the potential to implement personalized strategies for altering brain activity associated with rumination to reduce suicidal thoughts and behaviors. In the proposed study we will determine the acceptability and feasibility of using real-time functional magnetic resonance imaging neurofeedback to reduce suicide-specific rumination, defined as “repetitive mental fixation on one's suicidal thoughts and intentions” in a transdiagnostic sample of 15 Veterans at elevated risk of suicide. We will also assess pre- to post-treatment changes in measures of suicide-specific rumination, disability, functional impairment, and quality of life in Veterans with a suicide attempt history following 2 real-time functional magnetic resonance imaging sessions (each one lasting ~50 minutes). Veterans will be provided signals from the brain to identify mental strategies (e.g., cognitive reappraisal) for reducing the connectivity influence of the medial orbital frontal cortex on the precuneus. During a subsequent “transfer” period Veterans will be asked to utilize the mental strategy that worked best for altering this connectivity, but without receiving any neurofeedback signals from the brain. Post-treatment clinical assessments will occur following each of the 2 rt- fMRI neurofeedback sessions and at 1 month following the second fMRI neurofeedback session. The novelty of the proposed work is underscored by the paucity of work using real-time functional magnetic resonance imaging neurofeedback in a Veteran population and the lack of studies to date targeting a brain network to reduce suicide-specific rumination. In t...