Blind Deconvolution of Postsynaptic Currents Figure 4. Evaluation of the algorithm’s performance. A, The novel algorithm reliably detects pairs of unitary EPSCs separated by about 0.25 ms, an interval about one-third that required by the MiniAnalysis program. In this and the subsequent panels, the results from the new algorithm are displayed in red and those from MiniAnalysis in blue. B, The accuracy of amplitude estimation is slightly improved by the new algorithm. C, A synthetic record consisting of 3968 EPSCs, of which three small segments are displayed, was used to evaluate the two procedures. D, The probability distribution of amplitudes determined by the new algorithm agreed more closely with the true distribution than did the result from MiniAnalysis. E, EPSC impulse-response functions were determined by the algorithms for the three schemas shown in this figure and compared to the true impulse response. ‘‘Pairs assay’’ and ‘‘Amplitude assay’’ refer to the tests plotted in panels A and B; ‘‘Complex record’’ refers to the test plotted in panel C. The new algorithm provided an excellent fit by all criteria. F, The new algorithm fit the true cumulative probability distribution of the inter- EPSC intervals, which was an exponential function. doi:10.1371/journal.pone.0038198.g004 could further impair our ability to observe multimodal amplitude histograms. Recent experiments have determined that a single presynaptic vesicle contributes only about a quarter to a half of the average postsynaptic EPSC amplitude at the hair cell’s auditory synapse [11]. Experimentally measured amplitude distributions neverthe- less show little evidence of multiquantal peaks (Fig. 2C, [11]). Should we be able to find evidence of multiquantal release in EPSC amplitude distributions? We used the simulation framework developed here to investigate the distinct contributions of the intrinsic noise of AMPA receptor binding and kinetics, experi- mental noise, and the deconvolution process to the blurring of peaks in the distribution of EPSC amplitudes. For typical parameters of postsynaptic AMPA receptors, we found that multiquantal peaks are sufficiently blurred to obscure the evidence for multiquantal release. Stochastic ligand binding and channel reclosure usually suffice to make the amplitude distribution appear unimodal. Because we are unlikely to observe multiquantal peaks in such experimental amplitude histograms, they provide little evidence to test hypotheses of multiquantal neurotransmitter release. We have developed a flexible framework to perform deconvolution of time series data in an efficient and automated manner. Any data in which underlying time-sensitive or rhythmic information has been blurred in a systematic way benefit from deconvolution. The applicability of this approach ranges from electrical current to gene-expression profiles and population fluctuations. We have explicitly demonstrated the algorithm’s relevance to experimental records containing stereotyped responses of varying amplitudes, such as those obtained during the recording of postsynaptic currents reflecting neuronal activity. Users can determine the statistics of events, PLoS ONE | www.plosone.org 7 June 2012 | Volume 7 | Issue 6 | e38198