Biophysical Journal 70: 2078-2091 (1996)
© 1996 the Biophysical Society

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Frerking, M Articles by Wilson, M Search for Related Content PubMed PubMed Citation Articles by Frerking, M Articles by Wilson, M

Effects of variance in mini amplitude on stimulus-evoked release: a comparison of two models.

Section of Neurobiology, Physiology and Behavior, Division of Biological Sciences, University of California, Davis 95616, USA.

ABSTRACT

The strength of synaptic connections between two neurons is characterized by the number of release sites (N) on the presynaptic cell, the probability (p) of transmitter release at those sites in response to a stimulus, and the average size (A) of the postsynaptic response from each site. Quantal analysis can determine N, p, and A, but the large variance in the amplitudes of minis at central synapses is predicted to obscure quantal peaks and render quantal analysis unusable. Recently it has been suggested that the variance in mini amplitude is generated by differences between release sites, rather than by quantum-to-quantum fluctuations at identical sites, and that this form of variance in mini amplitude reduces the amount of variance expected in quantal peaks. Using simulations, we examine the possibility of resolving quantal peaks assuming either form of variance in mini amplitude. We find that individual quantal peaks are resolvable in neither case, provided that the uniquantal distribution is similar to the mini distribution. Because this lack of resolution compromises the utility of quantal analysis, we develop a general description that can solve N and p, given the statistical parameters of the mini distribution and the evoked distribution. We find that this description is relatively insensitive to the source of variance in mini amplitude.

This article has been cited by other articles:

				H. Taschenberger, V. Scheuss, and E. Neher Release kinetics, quantal parameters and their modulation during short-term depression at a developing synapse in the rat CNS J. Physiol., October 15, 2005; 568(2): 513 - 537. [Abstract] [Full Text] [PDF]

				J. B. Demb, P. Sterling, and M. A. Freed How Retinal Ganglion Cells Prevent Synaptic Noise From Reaching the Spike Output J Neurophysiol, October 1, 2004; 92(4): 2510 - 2519. [Abstract] [Full Text] [PDF]

				V. Scheuss, R. Schneggenburger, and E. Neher Separation of Presynaptic and Postsynaptic Contributions to Depression by Covariance Analysis of Successive EPSCs at the Calyx of Held Synapse J. Neurosci., February 1, 2002; 22(3): 728 - 739. [Abstract] [Full Text] [PDF]

				A. C. Meyer, E. Neher, and R. Schneggenburger Estimation of Quantal Size and Number of Functional Active Zones at the Calyx of Held Synapse by Nonstationary EPSC Variance Analysis J. Neurosci., October 15, 2001; 21(20): 7889 - 7900. [Abstract] [Full Text] [PDF]

				M. A. Freed Rate of Quantal Excitation to a Retinal Ganglion Cell Evoked by Sensory Input J Neurophysiol, May 1, 2000; 83(5): 2956 - 2966. [Abstract] [Full Text] [PDF]

				S. Royer, R. L. Coulson, and M. Klein Switching Off and On of Synaptic Sites at Aplysia Sensorimotor Synapses J. Neurosci., January 15, 2000; 20(2): 626 - 638. [Abstract] [Full Text] [PDF]

				M. Frerking, S. Borges, and M. Wilson Are Some Minis Multiquantal? J Neurophysiol, September 1, 1997; 78(3): 1293 - 1304. [Abstract] [Full Text] [PDF]