Some relevant points:
1. The neocortex in the brain can carry out some (habitual) bodily functions. It can analyze “incoming sensory data to the brain” and control some functions without the mind (hadaya vatthu) getting involved. A good example is driving to work or school, which one repeats day after day. Neural connections for that activity get stronger with repeated use; it can happen automatically without the mind getting involved after a while. Sometimes, we drive to work while thinking about something else (or while in a serious discussion with a passenger) and still get there safely.
- The neural networks in Artificial Intelligence (AI) work similarly. In this case, AI can learn from millions of people’s driving habits fed (via video) by its programmers. Thus, “self-driving car technology” has the potential to be better than any single driver. However, there is no “intelligence” involved in this case. The technology would be as good as the information it gets in the training phase.
2. The information that the “seat of the mind” (hadaya vatthu) gets is determined by the health of the brain. This is why older people start having memory issues with age when the brain function gradually diminishes. Specific problems with the brain, like Alzheimer’s disease, can change one’s personality.
- The case of Phineas Gage that you mentioned is another example. Damage to certain areas of his brain led to a change in his personality.
This is a complex but fascinating subject. I will write about it in a post one day when I have the time.
P.S. The point here is that whatever happens to the brain becomes irrelevant after one attains the Arahant stage. The mind can NEVER become defiled again, whether the brain sends it the wrong information (or even no information.)