Conde Nast Portfolio has a nice summary - a lengthy piece describing the growth: "It seems far out even for the neurotechnology industry, a rapidly growing cluster of companies—small upstarts as well as pharmaceutical giants—that want to alter your gray matter and make billions of dollars in the process. These firms are trying to adapt groundbreaking research into the basic workings of the brain to new drugs for ailments ranging from insomnia to multiple sclerosis. Some companies are trying to regrow portions of the brain using stem cells. Others have developed implants to insert into a person’s head to control seizures and restore hearing."