This item can also be gained by simply killing Old Lady Gibson's dog Rey yourself and taking it off of his body.
- It is possible to obtain two of his brains, but not at the same time. Sometimes Rey can glitch to Helios One, and will become hostile when entering the field of solar panels. This happens if you have a companion (possibly Boone). You can kill him and take his brain to Doc Henry for the transplant, then later, go back to Old Lady Gibson and there will be the option to buy Rey's brain off her for 700 caps.