This is a linkpost for http://waitbutwhy.com/2017/04/neuralink.html
I think I am unsure what properties of future tech you think will lead to more MAD style situations than we have currently. Is it hard takeoff?
The key ingredient for a MAD situation as far as I can think is some technology with a high destructiveness potential distributed among multiple agents who cannot trust each other. To reduce my whole argument to its cartoon outlines: serious brain augmentation seems about as good an idea as handing everyone their own nuclear arsenal.