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    Dopamine Drugs Are Turning Parkinson's Patients Into Picassos

    Written by

    Kelly Bourdet

    Dopamine is an important neurotransmitter, one whose functions is myriad and includes motor control, pleasure response, and habit reinforcement. Levels of dopamine in the brain have long been linked to a feeling of well-being, impulsivity control, and creativity.

    In a study in Behavioral Neuroscience, researcher Prof. Rivka Inzelberg of Tel Aviv University's Sackler Faculty of Medicine investigated an intriguing trend she first noticed at her home Sheba Medical Center clinic. Patients undergoing treatment for Parkinson’s disease began to attempt and excel in entirely new creative pursuits. Her staff, which regularly received gifts of candies from their patients during the holidays, began receiving art of all kinds instead. And all this art was created by Parkinson’s patients being treated with “either synthetic precursors of dopamine or dopamine receptor agonists, which increase the amount of dopamine activity in the brain by stimulating receptors.”

    The tale is reminiscent of Oliver Sacks' famous "Awakenings" experiments with L-DOPA and patients with a Parkinson's-like disease. In Prof. Rivka's study, one woman became an award-winning poet despite never having written before. Another patient cannot walk because of his Parkinson's symptoms, but found ways to carve elaborate wooden sculptures. 

    Parkinson’s is a degenerative disease in which dopamine-producing neurons break down. This dopamine deficiency leads telltale motor problems such as difficulty beginning motions, tremor, and paralysis. It has long been speculated that abnormally high dopamine levels within certain neural systems are related to psychosis and schizophrenia. In fact, many traditional “anti-psychotic” medications act on the D2 (dopamine 2) receptor, reducing the amount of dopamine that can bind.

    This isn’t the first time that Parkinson’s patients undergoing dopamine replacement therapies have made the news. There have been an alarming number of stories in which individuals with no prior history of gambling problems went on to become gambling addicts while on medication to treat their Parkinson’s. Dopamine acts across many areas of the brain, and the disease doesn’t affect all areas equally. Thus, depending upon the differences in damage, dopamine drug treatment can potentially correct or overcorrect dopamine levels.

    Alain Dagher, a researcher at McGill University who wrote a 2009 article on the subject, suggested that Parkinson’s medications might sometimes push levels to higher than normal levels in less-affected centers such as the ventral striatum, one of the most important areas for the brain’s reward system 

    But the ways in which dopamine affect behavior and thought are vastly complex, and not yet understood. It gets very complicated, and much research is needed. But sometimes dopamine receptor agonists, perhaps counter intuitively, act to stop neurons from firing. Researchers believe that the “midbrain and striatal dopamine-producing neurons normally express a kind of dopamine D2 receptor at the ends of their output fibers.” These autoreceptors make up part of a negative feedback loop, restricting the flow of dopamine when it becomes too high.  

    In 2010, researchers found a correlation between divergent thinking (related to creativity) and low dopamine receptor 2 binding potential (D2BP) in the thalamus. Because it’s not possible to count the number of dopamine receptors in the brain, researchers investigated the “binding potential,” in other words, the potential for dopamine to bind to receptors, thus giving an indirect measure of dopamine 2 binding receptor density.

    Painting by one of Prof. Inzelberg's patients (via American Friends of Tel Aviv)

    The thalamus is a relay center within the brain, sorting through information and making connections. It is because of this function that both the brain's thought processes and their interaction with their surroundings and convey meaning and ideas are dependent on this brain center. Associate professor Dr. Fredrik Ullé of the D2BP study indicated that, “fewer D2 receptors in the thalamus probably means a lower degree of signal filtering, and thus a higher flow of information from the thalamus.” So the novel connections and thinking patterns of creative individuals are possibly a scaled-back and socially acceptable version of the bizarre and random thinking patterns of some mentally ill.

    Are high dopamine levels responsible for enhanced creativity in these patients? Or is it something else? Are they somehow less inhibited due to the drugs, and thus able to act on previously unrealized creative talents? Perhaps the disease itself has destroyed certain dopamine receptor neurons, mimicking the state of the creative individuals shown in the D2BP study, and the addition of dopamine agonists to the altered neural landscape affects the individuals in novel ways.

    These patients' sudden bursts of creativity might provide new insight into what changes in dopamine levels within different areas of the brain can mean for both the sick and the healthy. And such dramatic personality changes--whether they be of the poetic or the compulsive-blackjack playing variety--reveals how we're all, essentially, at the mercy of our fluctuating neurochemicals. Our understanding of psychiatric drugs is so imperfect; we often try to just pour on what we think is missing, but the brain is far, far more complex than that. 

    Follow Kelly Bourdet on Twitter: @kellybourdet

    Illustration by Lydia Kibiuk. Adapted from Brain Facts, published by the Society for Neuroscience
     

    Topics: parkinson's, disease, dopamine, israel

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