Brain Mechanisms of Pleasure and Addiction

In the beginning, 1954 to be exact, psychologists James Olds and Peter Milner wanted to study more on brain mechanisms. Olds and Milner began testing on rats (rats had the closest brain structure to humans) to see whether stimulation of a certain brain area might influence which direction a rat turns or in their words, "Ask animals how they felt."

They would implant electrodes in rats septum of the brain and placed them in boxes where they could press a lever to produce electrical self-stimulation of the brain. With electrodes in the septum and certain other places, rats sometimes pressed as often as 2,000 times per hour. Later on researchers found many brain areas that rats would work to stimulate. All those areas had axons that directly or indirectly increase the release of dopamine or norepinephrine in the nucleus accumbens.

The nucleus accumbens is central to reinforcing experiences of all types. And maybe it was true; that drugs possibly created this sense of pleasure because they stimulate the same areas in the brain just like sex or food. If you simply imagine something pleasant, you activate your nucleus accumbens.

They also developed another experiment to see how far rats would go for stimulation. They electrified a grid, so that every time the rat crosses to the other end of the grid in order to reach the pedal that would stimulate the brain, it would receive a painful shock to it's feet. Do you think the rat would take that risk? Unfortunately, it would; a rat that craved for stimulation is like how they described it, "like a starving rat brave to get food."

Thanks to Olds technique of self-stimulation of the brain, it gave other scientists a way to test the addictive potential of drugs and to find out where in the brain they acted. Reinforcement has two components that psychologists called "wanting" and "liking." Most of the time, you would want something that you liked, but in the end, wanting (motivation) is not always the same as liking (pleasure). When it came to addictive drugs, the liking-wanting distinction was important because research showed that people addicted to a drug showed an overwhelming, all-consuming drive just to obtain the drug, even though it no longer provided much pleasure. When scientists found out that nearly all abused drugs would increase dopamine release in the nucleus accumbens, they concluded that by removing the dopamine neurons out of the brain, it would decrease their self interests such as drugs.    

From the information I processed from the video, it got me thinking; if scientists who study on addictive drugs know from which area produces self-stimulation of the brain from that drug, and know they can remove it, then why haven't we (or at least I haven't) seen this procedure being done more often? Most of time you would see drug addicts going to counseling or rehabilitation centers. So why is that? Is it because the procedure is not FDA approved, it's too expensive, hmmm...