NIMH stands for the National Institute of Mental Health. Their website is: http://www.nimh.nih.gov/index.shtml
Mrs. Frisby and the Rats of NIMHEdit
The rat colony originated from a farmers' market, but were captured by NIMH. There, they were given injections, put in cages, given tasteless scientifically engineered pellets (for food), and put in mazes. Dr. Shultz, Julie, and George (who are neurologists and biologists) were the scientists who did experiments on the rats. At NIMH, they were taught to read (the rats in Group A were given special injection). Testing Group A was given injections that made the rats smarter, and also were injected with steroids to prolong their life.