The brain is not an easy organ to study. While autopsies can reveal the structure of neural connections, only living, active brains can give insights into the chemical processes at work in healthy people. Drilling holes in people’s heads and inserting probes, however, is not typically the first choice of scientists. Thus, few opportunities exist for researches to test new apparatuses. This study is of those rare opportunities, and results in a successful test with a surprising outcome.
Dopamine is a neurotransmitter often released as neurons communicate with one another. To track the real-time release of dopamine during decision-making, researchers modified existing instruments to be sensitive to the neurochemical and tested it on a volunteer already undergoing deep brain stimulation therapy for Parkinson’s disease. The subject then participated in a classic economic game in which a series of decisions on how much to invest in a stock market were made based on the market’s previous performance during the game. To the researchers delight, the new device worked very well in detecting the real-time release of dopamine. To their surprise, the amount secreted during the game was a direct indicator of how well the market would do on the next turn, regardless of how much the subject invested on that turn. In fact, by creating a computer program that bet all or nothing based on dopamine levels from the previous five turns, the researchers were able to gain 175 percent on their original allotment, more than twice what the subject was able to achieve.
In order to understand the inner chemical workings of a live brain, scientists must first be able to track the chemical reactions occurring in real-time as decisions are being made. This study proves that a new instrument designed to detect the release of dopamine with millisecond precision works in a human brain.
Food for Thought:
Despite what the person playing the game decided to do in the stock market, the release of dopamine in the brain accurately predicted what the stock market would do in the next turn. As researcher Ken Kishida put it, “I often wonder whether there is a feeling associated with these dopamine fluctuations and whether there is any connection with that 'gut feeling' people sometimes ignore.”
Where to Find It:
Kishida KT, Sandberg SG, Lohrenz T, Comair YG, Sáez I, Phillips PEM, Montague PR. Sub-second dopamine detection in human striatum. PLoS ONE, 2011; 6(8):e23291.