Molecular Mechanisms of Neuronal Connectivity ABSTRACT The proposed meeting to be held at Cold Spring Harbor Laboratory on “Molecular Mechanisms of Neuronal Connectivity” on September 8-12, 2020 will assemble leaders in the field, junior faculty, postdoctoral fellows and graduate students to discuss new, cutting-edge developments in the areas defined in the meeting title. This proposal seeks support for the twelfth of a biennial series of meetings held at Cold Spring Harbor Laboratory that has emerged as the premiere meeting in the world for this field. Topics to be discussed for the 2020 meeting will include: programs of circuit wiring, axon targeting, axon regeneration, synapse assembly, synapses in neural circuits, glial control of neuronal circuitry and neuronal repair. The 2020 meeting will include a new session on structural biology for understanding the molecular mechanisms underlying circuit wiring and a new session on applications of the latest new technologies to accelerate the discovery in this important area of neurobiology. Diverse experimental approaches (including cell biology, biochemistry, genetics, structural biology, computational biology and electrophysiology) and systems (including various vertebrate and invertebrate model systems for investigating neural connectivity and function) will be highlighted. Given the diverse approaches currently employed in this field, communication among international researchers is essential to advance research and understanding of fundamental mechanisms that regulate wiring of the nervous system and how these mechanisms may relate to the causes and potential cures for neurological disease. Oral presentations will be selected by the session chairs in consultation with the organizers. Each session will be chaired by two leading scientists in the field and the session chairs will give presentations on their cutting-edge research. Selected speakers primarily include graduate students, postdoctoral fellows and junior faculty. Three special lectures will be presented to provide essential background critical to stimulating discussion between scientists working on related but distinct areas. There will also be two poster sessions where a majority of participants can present their work. The meeting will be of moderate size, and we expect 250-350 neuroscientists in attendance.

Molecular Mechanisms of Neuronal Connectivity LAY STATEMENT The precise wiring, or neuronal connectivity, of the nervous system is the foundation upon which all other aspects of brain function are based. Neuronal wiring is achieved in a series of discrete stages. First, neurons become `polarized', extending dendrites that receive input from other neurons and a single axon that conveys information to other neurons. Next, `axon guidance' describes the process by which the axon is guided to the correct target, often extending great distances through the developing body and brain. Once in the appropriate target region, the axon forms specialized connections with other neurons, a process that is termed `synapse formation'. Finally, neural circuitry is refined through the elaboration or elimination of synaptic connections. Understanding these sequential processes has profound implications for human health. Regeneration of damaged axons and neural circuitry will require a clear understanding of development. Diverse neurological diseases are now being clearly associated with defects in these processes. This conference of international scientists will meet to discuss the latest research in this important field of axon wiring, dendrite formation, synaptogenesis, regeneration and degeneration of neuronal connections.