Exponential sum-fitting of dwell-time distributions without specifying starting parameters.

Abstract:

:Fitting dwell-time distributions with sums of exponentials is widely used to characterize histograms of open- and closed-interval durations recorded from single ion channels, as well as for other physical phenomena. However, it can be difficult to identify the contributing exponential components. Here we extend previous methods of exponential sum-fitting to present a maximum-likelihood approach that consistently detects all significant exponentials without the need for user-specified starting parameters. Instead of searching for exponentials, the fitting starts with a very large number of initial exponentials with logarithmically spaced time constants, so that none are missed. Maximum-likelihood fitting then determines the areas of all the initial exponentials keeping the time constants fixed. In an iterative manner, with refitting after each step, the analysis then removes exponentials with negligible area and combines closely spaced adjacent exponentials, until only those exponentials that make significant contributions to the dwell-time distribution remain. There is no limit on the number of significant exponentials and no starting parameters need be specified. We demonstrate fully automated detection for both experimental and simulated data, as well as for classical exponential-sum-fitting problems.

journal_name

Biophys J

journal_title

Biophysical journal

authors

Landowne D,Yuan B,Magleby KL

doi

10.1016/j.bpj.2013.04.030

subject

Has Abstract

pub_date

2013-06-04 00:00:00

pages

2383-91

issue

11

eissn

0006-3495

issn

1542-0086

pii

S0006-3495(13)00463-3

journal_volume

104

pub_type

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