Purpose:
To optimise the decimation of binary sequences for use in multifocal recording with particular reference to use of short sequences, and to provide an educational tool.
Methods:
We have created a mathematical tool to examine a binary sequence and check its properties. With a given set of restrictions entered by the user, such as the number of separate channels required, the number of base periods in the recording epoch, which (how many) higher-order Kernels to test for etc., the tool will find a set or sets of sequences from the master sequence which have the least number of possible overlaps or contaminations between channels. The figure below shows FOK/SOK kernel cross contamination using real data.
Results:
The task can be reduced to a set of formulae. Published examples of decimation include simple methods of selection of the stimulating sequences such as maximum or equal separation. Our tool shows these methods to be unsuitable.
Conclusions:
Using this tool, binary sequences can be tested for suitability in multifocal recording. Not surprisingly, short sequences provide only a limited number of options when a large number of channels are required, and are therefore most in need of examination and optimisation.This tool will be available using a web-based implementation over the Internet via a MatSOAP connection (www.matsoap.org.uk). All software (MatLab and JavaScript) will be available as Open Source code from www.liverpooleye.org
Keywords: electroretinography: non-clinical • electrophysiology: non-clinical