Presynaptic plasticity

Published on April 2, 2014 Updated on April 9, 2014   54 min

Other Talks in the Series: Synapses, Neurotransmitters and Receptor Channels

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Hello. My name is Bob Zucker. And I'm at the University of California Berkeley. You have selected a Henry Stewart Talk on presynaptic plasticity.
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Neurons rarely fire single isolated action potentials. They signal information with trains of spikes that could be more or less regular, irregular, bursty, or sparse. When these action potentials invade nerve terminals, they evoke transmitter release at synapses, exciting or inhibiting neighboring cells to communicate and process information. Synapses transmit signals of this activity in complex ways. The postsynaptic potentials they generate are rarely constant. They may wax or wane or both compared to their amplitudes to infrequent presynaptic action potentials. At vertebrates central synapses, the slide shows the effects of a natural pattern of presynaptic spikes on the top rows, evoking a mixture of facilitated and depressed PSPs, shown in the graph. Responses are often complicated. They can grow, then decline, and then sometimes even grow again during a burst. And afterwards, they can be larger or smaller than isolated responses. When changes in synaptic efficacy occur in a timeframe of seconds or, at most, a few minutes, the changes are classified as short-term synaptic plasticity. The underlying mechanisms and physiological roles are distinct from longer lasting changes in transmission lasting hours or days and referred to as long-term potentiation or depression. These are discussed in a separate Henry Stewart Talk, while here I will consider only short-term synaptic plasticity.