Currently it requires an invasive and risky brain surgery which AFAIK would be a definite no-go. At least in the US, this would likely be considered extremely inhumane unless it could be done without such significant risk of death or brain damage - given the nature of the surgery I find that unlikely.

In the cases where an invasive brain surgery would be permitted, I imagine torture would already be an option. Keep in mind torture doesn't have nearly the same risk of death and permanent brain damage as an invasive brain surgery.