pat - or pattern files are used in Auryn to defined patterns as a subset of neurons of single NeuronGroup with associated activity (gamma) value between zero and one. They are a human readable exchange format and are understood by a range of Auryn objects. SparseConnection for instance implements a set of functions to load such pattern files as cell assemblies (or synfire chains) into the connection matrix. PatternMonitor on the other hand allows to record firing rates from neural subpopulations specified by pat files and finally WeightMonitor has a set of functions to monitor synaptic weights within or between neurons specified in a pat file.
The first bit of a pat file could look like this:
# 2 blocks # pattern 0 0 0.866623 1 0.742221 2 0.271302 398 0.208315 399 0.123721 # pattern 1 400 0.972103 401 0.057406
where the first column specifies the NeuronID and the second column the associated gamma value. Different patterns in a single pattern file are separated by 2 or more line breaks. Comments can be added to the file and have to be marked with a leading #, which has to be the first character on a line. If the second column is missing the value will be interpreted as 1.0. Therefore a pattern file without second column is also a valid pattern file.