Extend NeuroML to incorporate rate based/neural mass models

[pgleeson]

Much work has already taken place for this in the GSoC for OSB:
http://neuralensemble.blogspot.com/2018/08/neuroml2lems-is-moving-into-neural-mass.html

This work has involved expressing neural masses/population units in LEMS format to encapsulate the dynamics of the rate changes. Links for projects with neural mass models in LEMS:
https://github.com/OpenSourceBrain/WilsonCowan
https://github.com/OpenSourceBrain/del-Molino2017
https://github.com/OpenSourceBrain/MejiasEtAl2016

Eventually some or all of these models could/should be mapped onto The Virtual Brain format.

[JohnGriffiths]

Re: mapping to TVB format - there is some functionality implemented in TVB for specifying simulations from .json .

e.g.

https://github.com/the-virtual-brain/tvb-documentation/blob/master/demos/sandbox/load_simulation_from_json.ipynb

It's still quite rudimentary and possibly buggy, but a useful direction might be to figure out the correspondences between this .json structure and the neuroml .xml structure.

[pgleeson]

Relevant for TVB: https://github.com/maedoc/tvb-lems

[pgleeson]

Another potential target simulation/analysis tool for these models: https://github.com/breakspear/bdtoolkit