I think that this is a foolish thought. A brain is about the size of a softball. 9-15 square inches. Unless you hit that brain or spinal cord, you are pretty much SOL. the whole skull is about the size of a big pummelo, and without a real serious hit, that was a complete miss. A graze on the skull won't disable a squirrel, even.
If you fire center mass to the torso, you are aiming at a target as large as the brain, the heart. You are aiming at a target twice the size of the skull, the lungs. And you are also firing at a target twice the size of the brain, and just as vulnerable, the spinal column. if you so much as strike a vertebra with a bullet, that target is going to go down. The spinal column is about 2" by 12". Then there are the kidneys and spleen and liver, and hits to any of them will instill enormous systematic shock.
When I have to fire at a person, How in the name of everything holy will I know that I have plenty of times and all those repeated opportunities to get a bullet into his brain? Before I even pull the trigger, I already know that he is going to be shooting at me, so why would I assume that I have the privilege of waiting for a perfect brain shot?
Only a great fool will choose to aim for the brain under a pressure situation, firing with a wing and a prayer, knowing full well that either he will make a near miracle hit, or a complete and total failure with a miss over or horizontally.
The only really intelligent and logical shot to take with a handgun in a combat situation is to fire for the chest cavity. No matter where you hit, in about a 10-12" x 14" shape, you are going to create a potentially disabling wound, if you have used an effective cartridge and bullet.
My handguns are all sighted in with only a single cartridge. Switching ammo to anything else in any of them would throw them off of target by as much as half a foot at 20 feet or so. Even so, I've found that without a doubt, I can't hit a 3" bull even 50% of the time in DA fire with any of my handguns, on astationary paper target.
I'd have to be a complete moron to try a brain shot in combat. I hope that nobody else even considers this idea.