Brian 2 + Python 3 version source code for the paper "Unsupervised Learning of Digit recognition using STDP"

This fork updates the code from https://github.com/zxzhijia/Brian2STDPMNIST to Python 3 and refactors most of the code.

https://github.com/zxzhijia/Brian2STDPMNIST is a fork of https://github.com/peter-u-diehl/stdp-mnist/ which updates it to Brian 2.