This proposal requests support for a unique international meeting, the biennial Neurobiology of Drosophila conference at Cold Spring Harbor to be held in 2021, the 19th meeting in this series. For the 2021 edition, the organizers have focused the meeting on topics of direct bearing on the central goals of the NIH Neuroscience Blueprint and BRAIN initiative, in particular the mission of NINDS, but also those of NICHD, NIDA, NIAAA, NIA, NIMH and NIAID. The meeting will explore the latest advances being made in the highly successful model system the fruit fly Drosophila melanogaster through the combined power of genetics, molecular biology, cell biology, electrophysiology, imaging, and behavioral analysis to address fundamental issues in neurobiology with direct relevance to human health and disease. The meeting will have eight oral sessions: 1) Circuit Formation and Function; 2) (Re)Generation of Neurons and Glia; 3) Sensory Integration and Behavior; 4) Technological Innovations; 5) Neuroscience and Evolution in Non-melanogaster Insects; 6) Neurological Disease and Injury; 7) Synaptic Transmission and Plasticity; and 8) Neur-omics. There will be three poster sessions presenting work drawn from each of these areas. Finally, there will also be two special plenary presentations: the keynote Benzer Memorial Lecture and the Elkins Memorial Lecture, which is an honor awarded to the student who has written the best Ph.D. thesis since the previous meeting. The 2021 Benzer Memorial Lecture will be given by Dr. Leslie Vosshall (Robert Chemers Neustein Professor and Howard Hughes Medical Institute Investigator at Rockefeller University, NYC), whose pioneering work has shed light on the control of complex behaviors by environmental cues and their modulation by internal physiological states. By vote of the previous participants, the meeting will remain of moderate size (~450 participants) in order to facilitate discussion, exchange of ideas and techniques, and to promote new collaborations in rapidly-evolving fields. Roughly half the attendees have previously attended the meeting, highlighting its importance and relevance, and the new attendees bring fresh ideas and extend the meeting's reach. All applicants will be encouraged to submit an abstract and the majority of participants, typically over 75%, will present a talk or poster. Speakers will be chosen by session leaders and meeting organizers from the most timely and interesting abstracts submitted a few months in advance of the conference: this will ensure that late-breaking science is covered in all of the talks. In the event that the conference is oversubscribed, participants will be chosen to include at least one representative from each participating laboratory. This meeting has always attracted investigators across many career stages and has a historically excellent record of promoting the scientific development of young investigators and women. To encourage participation by junior investigators, a graduate student will present the Elkin's Lecture, an honor given to the student who has written the best Ph.D. thesis since the previous meeting.