What I remember from the plot:
In this short story, a man who suffers of anger management problems (probably on criminal levels, or in order to prevent them) gets an advanced, experimental treatment based on electrical stimuli directly to the brain.
These stimuli are controlled by a chip implanted in his brain; the position of the electric contacts is extremely important, because missing the exact point of the brain to control would lead to disastrous results.
The chip would detect "anger spikes" and would stimulate the brain in order to reduce them and prevent any anger explosion from the guy.
The problem is that, when the anger spike is prevented, it is kind of replaced by a pleasant sensation. This causes a feedback loop where the brain subcounsciosly tries to cause anger spikes to get pleasure in return.
This causes the frequency of these events to increase exponentially, until they are basically constant, leading to a result antipodal to the desired outcome. The man escapes the hospital before the doctor, who detected this feedback loop from his charts, can actually stop the treatment.
The man then tries to destroy the hospital computer, which is located in the basement, but he is stopped before he can do much damage.
Other information from the story
The story itself should have been written around the '70-'80, because the computer was as large as the room (the basement).
If you need any more information, please ask in the comments and I will try to answer as best as I can, and sorry for my english.