If you noticed anything getting worse after using fields, subliminals, energy work, etc, there are plenty of threads about how to clean those from the system.
You can use the intercessions and ask the different beings to do it, for example.
There was even a recent discussion:
But if you look, you will find plenty more, with plenty of suggestions.
One I’d personally use is
https://forum.enlightenedstates.com/t/servitor-the-healer/82170
As for what you want, my advice would be to focus on brain healing fields (Plasma Brain of Youth is a great one), and then on fields that provide the kind of wiring/outcomes you wish.
The fields deliver, so you will get the expected outcome and not anything else. If you want to have “your brain”, use healing fields.
If you’re going to use wiring fields, you will be growing your brain in whatever way the field does. So you choose based on that.
Maybe some more experieced members chime in and have better advice.
Good luck ^^