This funding opportunity announcement (FOA) encourages applications for multi-center clinical trials focused on neurological emergencies. Successful applicants will collaborate and conduct the trial within the NIH SIREN Network. The NIH SIREN Clinical Coordinating Center (CCC) will work with the successful applicants to implement the proposed trial efficiently and the SIREN Data Coordinating Center (DCC) will provide statistical and data management support. The NIH SIREN hubs and their affiliated clinical sites will provide on-site implementation of the clinical protocols.The NIH SIREN Network will also be uniquely poised to collaborate with other US and international consortia necessary to conduct larger, definitive trials of promising interventions for neurological emergencies.Multi-center clinical trials in stroke treatment, recovery, or prevention supported by NINDS will be conducted in the NIH StrokeNet, and not within SIREN. Applicants do not need to be part of the existing SIREN infrastructure to apply under this FOA.