The AAT+TF-CBT project (Shenk, Co-I) is an NIH-funded (Allen, PI: R21HD091887) randomized feasibility trial examining the tolerability and acceptability of delivering TF-CBT while a service dog is present throughout the active phase of treatment. TF-CBT is one of the few well-established interventions for children experiencing maltreatment and this clinical trial is examining whether introducing a service dog during standard administration of TF-CBT enhances treatment effects above and beyond TF-CBT alone. The laboratory’s contribution to this project is overseeing the collection, editing, and analysis of electrocardiogram data obtained at pre-treatment as well as at strategic sessions during the active treatment phase. Current work on this project involves generating estimates of the respiratory sinus arrhythmia (RSA), an index of parasympathetic control of cardiac activity, in 30-second epochs and modeling within and between session change in RSA as a potential mechanism of action in TF-CBT when treating child maltreatment-related post-traumatic stress disorder (PTSD). Potential opportunities for CMT32 Fellows include modeling RSA reactivity to the Trier Social Stress Test administered at pre-treatment to determine whether such reactivity is related to within-session changes in RSA and PTSD symptom severity at post-treatment.