PROJECT SUMMARY The proposed “Brain Barriers” formerly known as the “Blood-Brain Barrier (BBB)” meeting, to be held at the Cold Spring Harbor Laboratory (CSHL) from April 7th - 10th 2021, will assemble leaders in the fields of central nervous system (CNS) barriers including the BBB, the blood-cerebrospinal fluid barrier, and the brain- meningeal barrier, to discuss the latest scientific advances that will elucidate barrier function in health and disease. This application seeks support for the seventh meeting of a biennial series of CSHL meetings on this topic. Similar meetings in the field organized by other non-profit organizations have historically focused on more physiological or pharmacological aspects of the BBB. In contrast, this premiere scientific conference will emphasize modern, multi-tiered approaches spanning cellular, molecular, transcriptomic, proteomic, genetic, and imaging technologies to elucidate CNS barriers biology throughout life. Brain barrier topics to be discussed during the 2021 meeting include: (i) Emerging concepts and hot topics; (ii) Imaging approaches; (iii) Development, plasticity, and specialization; (iv) Systems, computational and cell biology; (v) Neuroimmune interactions; and (vi) Aging, senescence and neurodegeneration. Recent fundamental discoveries in CNS barriers including new knowledge regarding meningeal lymphatics, the diverse approaches leveraged to investigate barrier biology, and the application of this body of work to many neurological diseases ranging from brain trauma, stroke, and tumors, to autoimmune and neurodegenerative disorders, have set the stage for an unprecedented scientific discovery. As such, communication within the international research community is essential for fostering collaborations and fueling future advances in the field. Each session will be chaired by a pair of leading scientists, one senior and one junior. Selected speakers will include 2-3 invited speakers as well as graduate students, postdoctoral fellows, and junior faculty selected from submitted abstracts. We will pioneer a new approach where we designate an entire session with platform presentations from selected young investigators. One keynote lecture presented at the beginning of the meeting will provide an overview of the field and the critical background to stimulate discussion throughout the meeting. There will also be two poster sessions, one panel discussion on “Stereotypes to diversity in science and beyond” followed by a workshop on “How to frame and write constructive and fair peer-review”. These sessions will provide support for the professional growth of all meeting attendees in particular women and minorities in STEM careers, and stimulate the scientific growth of all young scientists. Two poster prizes (1st and 2nd place) will be presented as late breaking short talks in the final session. The meeting has grown steadily since its inception in 2008. We anticipate a moderate size (>200 participants) includ...