Abstract: Series 104, Lecture 3
The Harvey Lectures Series 104 (2008—2009)
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Lecture #3: Thursday, January 15, 2009 — Time and Location
Fundamental Units of Synaptic Communication Between Brain Cells
Richard W Tsien, PhD
George D Smith Professor of Molecular and Genetic Medicine
Department of Molecular and Cellular Physiology
Stanford University
Stanford, California
Brain cells communicate with each other by means of synapses. Typically, several thousand chemical synapses converge onto a single postsynaptic neuron. The computational power of CNS circuits relies critically on an abundance of synapses, and has thus benefitted from their extreme miniaturization. The ~1 µm size of typical CNS synapses poses challenges, both for their cell biology and for our experiments. Fortunately, powerful methods have emerged that allow us to study presynaptic terminals and postsynaptic target structures unambiguously. We have characterized key features of individual synapses, single synaptic vesicles, and quantal units of neurotransmission. Our work has addressed some fundamental questions. Does release of a single vesicle cause saturation of postsynaptic receptors? How do single presynaptic terminals change during long-lasting synaptic plasticity? How independent are modifications of post- and presynaptic elements? Does vesicle fusion occur solely by the classical mechanism, full collapse into the surface membrane, or does it also use a mode called kiss-and-run, wherein the fusing vesicle stays more or less intact and can then be reused? Are all vesicles created equal or are some unusually well-equipped to undergo release?