Hi in last few weeks i loking in more details how tDCS works and how inprove it.

here is few ideas how create a good protocol:

1.Find the target
Find a specific neural structure and brainwaves

2.Cortical folding
Find cortical folding of this area.
How is interidivitual variability of cortical folding?

3.Adjust ealectrode size and placemet
Skin iritation/pain limit
Field orintation
Field intensity
(model is be best but may be posible partialy aproximate this data)

4.Filed intensity in the cortex , treesholds of polarization of varioous parts of neurones and effect of the whole nework

5.Stimulation parameters nad waveform
Try to aproximate from the model and use EEG to observe changes. (idelay use with fMRI)
If it not go wll try to create feed back loop with EEG and constantly change the stimulation parameters (use frequenci folowing responce and other stuff).
*in case if you traing changing brainwaves too
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Currently used protocols with standart tDCS pads is very bad in focality
and didnt bother with many importhant things.Clinical researchers copy protocol one from ther without thinking what is actualy work (use oversimplified models).