Dopamine is the “politically correct” catch phrase in today’s society. People talk about getting their dopamine rush from music, chocolate, cheesecake, etc. Cocaine, methamphetamines, alcohol, Ritalin, Adderall and nicotine are also known to stimulate the brain and give off that “feel good”lift. From the two different associations you can see that “feeling good” is not always good for you.
Dopamine is the brain’s reward system. It gives you a happy feeling and makes you want to continue to feel that way. Soon you are a slave to the pleasure it gives you, “which is why it is called “dope-a-mine.”
At a meeting of the Society of Neuroscience in Chicago, neuroscientists spoke about dopamine being more about drive and motivation, and less about pleasure and reward. “When you can’t breathe, and you’re gasping for air, would you call that pleasurable?”said Nora D. Volkow, a dopamine researcher and director of the National Institute on Drug Abuse. “Or when you’re so hungry that you eat something disgusting, is that pleasurable?” According to Dr. Volkow, the oxygen and wolfing scenarios are something that certainly are not pleasurable, but the dopamine pathways are open to full throttle.”The whole brain is of one mindset,she said. The intense drive to get you out of a state of deprivation and keep you alive.”
Volkow says, “Dopamine is also part of the brain’s salience filter, its get-a-load-of-this device. You can’t pay attention to everything, but you want to be adept as an organism at recognizing things that are novel,”Dr. Volkow said. “You might not notice a fly in the room, but if that fly was fluorescent, your dopamine cells would fire.”
Our dopamine-driven salience detector focuses on familiar objects that we give value to, whether they are positive or negative value. This would means objects that we want, and objects that we fear. For example: If we love chocolate, our dopamine neurons probably fire up at the sight of a little chocolate bean lying on the counter. But, on the other hand, if we fear cockroaches, those same neurons may fire even harder when we see that little chocolate bean has six legs and is running away. Your body gets mixed signals, and it could well entail other signaling molecules, like opiates or stress hormones. Dopamine simply makes a relevant object almost impossible to ignore.
Is it possible the brain can ignore signals from dopamine? A report in Nature Neuroscience, by Regina M. Sullivan of New York University Medical Center, Gordon A. Barr of Children’s Hospital of Philadelphia and their colleagues, found that, rats older than 12 days would quickly develop a dislike to any odors that came at the same time as they were given a mild electric shock. Younger rats, on the other hand, who had their mothers nearby when they were presented with an odor at the same time they received the electrical shock actually showed a preference for the odor.
The researchers traced the revulsion to a suppression of dopamine activity in the amygdala, where fear memories are born. The infant rats, who know their mother by smell, Dr. Sullivan explained, did not learn to avoid their mother, even if her presence was associated with pain. It goes to show that even an abusive caretaker is better than none.
The dopamine production population in the brain are small, less than 1 percent of all neurons generate the neurotransmitters for dopamine. Most of them exist in midbrain structures, like the substantia nigra, the part of the brain that helps to control movement. Degradation of this dopamine results in the tremors and other symptoms of Parkinson’s disease. There is also dopamine activity in the prefrontal cortex, right behind the forehead (where impulses are controlled, stories are written and excuses made up). Starvation of these prefrontal dopamine molecules is believed to be the cause of schizophrenia.
Wherever they are located, brain cells respond to the release of dopamine through one or more of five distinct dopamine receptors that reach out to proteins designed to respond to the molecules. The dopamine transmitter is also another key player. It acts like the “janitor that picks up used dopamine molecules and sweeps them back into the cells where they were born.”A recreational drug, like cocaine, tends to block that transporter and allows dopamine to linger in the neuronal pathway and keep punching its signal along.
Each person differs in how his or her body responds to dopamine. Some researchers are looking at genetic reasons why this happens. According to Northwestern University’s Dr. Dan T. A. Eisenberg, a relatively elongated version of dopamine receptor No. 4 exists and it has a tendency toward impulsivity and risk-taking behavior, particularly financial risk-taking.
About the author:
Ron White is a two-time U.S.A. Memory Champion and memory training expert. As a memory keynote speaker he travels the world to speak before large groups or small company seminars, demonstrating his memory skills and teaching others how to improve their memory, and how important a good memory is in all phases of your life. His CDs and memory products are also available online at BrainAthlete.com.
Sources:
New York Times “The Straight Dope: The Role of Dopamine in the Brain: http://learning.blogs.nytimes.com/2009/10/28/the-straight-dope-the-role-of-dopamine-in-the-brain/
New York Times “ A Molecule of Motivation, Dopamine Excels At Its Task:
