What is it?Edit
While P-Brains are least common of all debris, they are most valuable. Tiny needs P-brains to run his internal systems, and while he's already a pretty smart cookie, he gets even smarter when he has more P-Brains.
How is it used?Edit
You collect many P-Brains throughout the game. You "attach" the brains to your guns to make them smarter (auto-aim, auto-fire, etc). This is useful if you don't like to manually do everything (It's like having a personal drone).