The National Institutes of Health (NIH) has announced a funding opportunity titled "Building in vivo Preclinical Assays of Circuit Engagement for Application in Therapeutic Development (R01 Clinical Trial Not Allowed)." This initiative aims to develop innovative neurophysiological and behavioral measures in animal models to enhance the early-phase therapeutic development for mental illnesses, addressing the challenges faced in novel treatment development over the past two decades. Successful applications must focus on optimizing these measures to reflect human assays, validating their sensitivity and selectivity through pharmacodynamic studies, and ensuring they are clinically relevant. The grant has an award ceiling of $250,000, with applications accepted until September 7, 2025. For further inquiries, interested parties can contact NIH Grants Information at grantsinfo@nih.gov or visit the opportunity's webpage at https://grants.nih.gov/grants/guide/pa-files/PAR-23-091.html.