In cyberpunk literature, technology inevitably makes its way down to the street. (Bruce Sterling notes that were Frankenstein a cyberpunk novel, the Things That Man Was Not Meant To Know would end up mass produced and on sale in cities all over the world.) No matter what a technology is intended to do, the street finds its own uses. (Walter Jon Williams' "Video Star" goes so far as to describe the process in which a main character makes homebrew plastic explosive from liquid bleach.) In Synners, Pat Cadigan introduces sophisticated neural technology, implants designed to do what the brain cannot. People with brain lesions will be able to compensate; people with epilepsy can avoid seizures; people with clinical depression gain access to the inner workings of their brain chemistry.
That's not the extent of it, though. (In cyberpunk, it never is.) Instead, people discover ways to abuse the implant tech:
"I'm going to die," said Jones.
The statuesque tatoo artist paused between the lotuses she was applying to the arm of the space case lolling half-conscious in the chair. "What, again?"
"Don't laugh at me, Gator." Jones ran a skeletal hand through his nervous-breakdown hair.
"Who's laughing? Do you see me laughing?" She shifted in her high stool..."I don't laugh at anyone who dies as often as you do. You know,s omeday your adrenal system is gonna tell you to fuck off, and you won't be back. Maybe someday real soon...Get help, Jones. You're an addict."
When the technology is invented to allow people to generate their own near-death experiences, I have no doubt that it'll become a novelty, a toy, a drug. If Synners has a motto, it's either "Change for the machines" or "More drugs." Cadigan's insight is that they're one and the same--getting high to create technology to get high by, to paraphrase a Spaceman 3 album title. Cyberpunk is misapplication of high technology; it's a natural end-point from a modern world where veterinary medicine finds a niche as a drug for clubbing and fertilizer makes terrorist bombs.