Dear colleagues, We would like to point the members of this list to an initiative which resulted from a workshop on collaborative model development <https://www.janelia.org/you-janelia/conferences/collaborative-development-data-driven-models-neural-systems> at Janelia Research Campus. A number of participants agreed to sign an open letter committing to releasing as open source all the software they develop for data analysis and modelling in their publications (whether or not the article is specifically about the software). The letter and current signatories can be found here: http://opensourceforneuroscience.org/ <http://opensourceforneuroscience.org/> A NeuroView article describing this initiative has just been published in Neuron: A Commitment to Open Source in Neuroscience <http://www.cell.com/neuron/fulltext/S0896-6273(17)30981-9>. While many on this list are already sold on the idea of making their own code publicly available, there is another significant statement in the open letter: "If and when asked to serve as peer-reviewers, we will henceforth ask authors about the availability of any code they have developed for data analysis and modelling which is essential to reproducing the results of their paper and require that this be shared publicly upon acceptance." We hope that this public commitment will make it clear to the wider neuroscience community that trying to publish work on the assumption that they will not have to release their code will become more and more difficult, and that the sooner they plan to make it available the better for them and for the wider field. Regards, Padraig Gleeson Andrew P. Davison R. Angus Silver Giorgio A. Ascoli