Project Summary The error-related negativity (ERN) is a biomarker of error processing that can predict future onset and worse outcomes of anxiety disorders in young children and is therefore a potential target to offset the development of anxiety disorders. Therapeutic interventions can reduce the ERN in a single session, but a number of factors make the ERN difficult to measure, such as requiring participants to spontaneously make mistakes on a small fraction of hundreds of trials in simple computer games that are far removed from daily life. Further, the ERN is quite sensitive to interpretation of the task instructions. The balance N1 is a comparable biomarker of error processing that can be evoked by a sudden disturbance to standing balance. Unlike the ERN, the errors that evoke the balance N1 are encountered in daily life, are under full experimental control, and evoke an involuntary behavioral reaction that requires no prior instruction, eliminating many of the problems with measuring the ERN. Further, the balance N1 is substantially larger in amplitude than the ERN and can be robustly observed in single trials. Preliminary data demonstrate that the balance N1 and ERN amplitudes are correlated within younger and older adult populations, suggesting the balance N1 may provide a robust measurement of the same underlying neural system. In the proposed project, the balance N1 and ERN will be measured in 128 children (ages 9-12, N=64 with anxiety disorders and N=64 without). While replicating prior findings that the ERN is enhanced in clinically anxious children, this project will be the first to test whether the balance N1 is similarly enhanced in anxious children (Aim 1). Then, this project will test whether the balance N1 and ERN amplitudes are correlated within and across both groups of children, and assess whether they account for unique or overlapping variance in anxiety status (Aim 2). The anxious children will then be randomized into a single-session computer-based intervention targeting hyperactive error monitoring or a control condition focused on healthy lifestyle choices. Our goal is to demonstrate that an intervention targeting hyperactive error monitoring can reduce the ERN—and test whether this effect transfers to a similar reduction of the balance N1 to test for shared underlying mechanisms (Aim 3). The proposed study may yield a biomarker of anxiety that is more robust and easier to measure than the ERN. Transfer of the intervention effect to the balance N1 would provide insight into prior work demonstrating that balance training can alleviate anxiety in young children, and well-documented benefits of psychotherapy to balance disorders. Collectively, these data may facilitate the development of multidisciplinary interventions for anxiety in children that target activity of the brain’s error monitoring system. This project will provide training in the use of event-related potential based biomarkers to study developmental psychopath...