Reorder microstate maps based on a template
Clustering algorithms do not yield a specific order of the clusters that is consistent across analyses of independent datasets. Once you have identified a series of microstate clusters, you therefore have to find a useful ordering and labeling of the classes that makes them comparable to other datasets. This may be the case when you have identified microstate class maps on the level of individual EEGs, and need to have them ordered in in a coherent way across the individual EEGs. You may also have group averages to be aligned, or you may want to align grand-average microstate class maps according to some published data.
- The sorting of microstates class maps on the level of individual microstate class maps and based on some mean microstate class maps is accessed thru the menu Tools->Microstates->Sort individual microstate maps according to mean"
- The sorting of microstates class maps on the level of individual microstate class maps and based on published templates is accessed thru the menu Tools->Microstates->Sort individual microstate maps according to published template"
- The sorting of microstates class maps on the level of mean microstate class maps and based on some mean microstate class maps is accessed thru the menu Tools->Microstates->Sort mean microstate maps according to a grand mean"
- The sorting of microstates class maps on the level of mean microstate class maps and based on published templates is accessed thru the menu Tools->Microstates->Sort mean microstate maps according to published template"
Here are a view examples of the dialog in EEGLAB:
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Sorting of individual cases based on a mean |
Sorting of means based on a template from the literature |
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Alternatively, the analysis step can also be started on the command line or using a script. In this case, the function to be called is
[ALLEEG,EEG,com] = pop_SortMSTemplates(ALLEEG,SetToSort, DoMeans, TemplateSet, IgnorePolarity)
typically followed by
[ALLEEG, EEG, CURRENTSET] = eeg_store(ALLEEG, EEG, CURRENTSET);
where the ALLEEG contains the structures with the EEG data, SetToSort is an index into ALLEEG identifying the datasets to be reordered, DoMeans being true limits the ALLEEG datasets to be included to those that already contain average microstate class maps, TemplateSet indicates the template that defines the sort order, and IgnorePolarity being true considers maps with reversed polarity as similar.