The National Institutes of Health (NIH) is accepting applications for the "Cellular and Molecular Biology of Complex Brain Disorders" program (R21 Clinical Trial Not Allowed). This funding opportunity supports high-risk, early-stage exploratory research on the biology of high-confidence risk factors for complex brain disorders. It focuses on intracellular, transcellular, and circuit-level mechanisms of neural function related to multifactorial risks, such as polygenic or environmental factors.

Eligible applicants include state and local governments, higher education institutions, nonprofits, tribal entities, small businesses, and for-profit organizations. No cost-sharing is required. Applications are due by January 8, 2025, with additional cycles open until September 7, 2026.

Proposals should target understanding the neurobiological impacts of individual or combined risk factors on molecular and cellular processes. Research may include hypothesis-generating or hypothesis-testing designs using in vivo, in situ, or in vitro paradigms such as model organisms or human cell-based assays. Studies should enrich data resources (e.g., Gene Ontology, FAIR Data Informatics) to connect disease risk factors with biological mechanisms and therapeutic targets.