Neuron
Volume 14, Issue 4, April 1995, Pages 795-802
Journal home page for Neuron

Article
Facilitation and depression at single central synapses

https://doi.org/10.1016/0896-6273(95)90223-6Get rights and content
Under an Elsevier user license
open archive

Abstract

Using whole-cell recording from CA1 hippocampal pyramidal neurons and minimal stimulation of Schaffer collaterals, we have studied what seem to be single synapses. Although the transmission at a putative single synapse is quite unreliable, the synapse can be made to release transmitter reliably in response to the second stimulus in a pair of stimuli that are presented in rapid succession (e.g., 50 ms separation). Statistical analysis of transmission failures seen with such paired pulse stimulation reveals that the majority of stimulus-evoked synaptic currents (>90%) are produced by a single synapse under the conditions of minimal stimulation, even if multiple synapses are actually present. Individual synapses appear to release either zero or one quantum; that is, a single synapse seems to have only one functional release site at any time. After the release site has been used, ∼20 ms is required to refill the site so that it can be used again.

Cited by (0)

Present address: Massachusetts Institute of Technology, Cancer Center, E17–353, Cambridge, Massachusetts 02139