Monetary gain stimulates activity in the brain — even the mere possibility of receiving a reward is known to activate an area of the brain called the striatum. A team of Japanese researchers measured striatum activation in volunteers performing a monetary task and found that high-risk/high-gain options caused higher levels of activation than did more conservative options. They also found levels of activation to increase with the amount of money owned. The results of this study are reported in the January 2010 issue of Cortex.
Tadashi Ino and colleagues, from the Department of Neurology at the Rakuwakai-Otowa Hospital and the Research Center for Nano Medical Engineering at Kyoto University, used functional magnetic resonance imaging (fMRI) to study changes in the brains of 17 healthy volunteers performing a monetary task. The volunteers were given an initial stock of money and then required to press repetitively one of two buttons, which resulted in either an increase or decrease of the money stock, depending on whether their choice agreed or disagreed with a number that appeared randomly after the button had been pressed. One button was a low-risk option, and the other involved high risk, so that more money was gained or lost when choosing the high-risk option. The volunteers were also able to keep track of the total money stock throughout the task.
The researchers found higher levels of activation in volunteers when choosing high-risk/high-gain options, rather than low-risk/low-gain, and when gaining money rather than losing money. It did not matter how much money was gained, as small gains stimulated the volunteers’ striatum as much as large gains. They also found that overall striatum activity increased with the total amount of money in stock.
According to the authors, these results show that “risky tactics and the pleasure of monetary gain are correlated with activation of the striatum,” demonstrating “the concept of the striatum as a major reward-related brain structure.”