Evoked neurotransmitter release: statistical effects of nonuniformity and nonstationarity.

Abstract
Recent studies of the mechanism of quantal neurotransmitter release assumed that the number of quanta released at each stimulation was binomially distributed and sought to estimate the binomial parameters n and p. Mathematical analysis and computer simulations showed that temporal variation in the number of eligible or filled release sites and either spatial or temporal variation in the probability of release at a site can drastically bias such estimates, while the experimental histograms remained statistically dpindistinguishable from those predicted by the binomial law. Interpretation of the estimates ~n and ~p in terms of ultrastructural or physiological characteristics of the nerve terminal is liable to significant error if departures from the binomial assumptions are not suitably assessed.