In a study published online January 12 in the journal Neuron, the research team helped identify areas of the brain involved in the choice between taking an immediate reward or deferring for a larger but delayed payoff. The decision involves a complex network that links multiple areas of the brain in a sort of complex feedback loop. “But in the instant before the choice is made, we can predict the outcome of the decision by listening to the firing activity in a single neuron,” said Daeyeol Lee, associate professor of neurobiology and psychology at Yale School of Medicine and senior author of the study.
Scientists have described in general terms how the brain responds to potential rewards, such as food, alcohol or sex. However, Lee’s team looked at the information processed at the level of both brain regions and individual cells. They recorded activity in individual neurons of monkeys as they were offered choices between smaller rewards or larger ones, which were delivered after delays. Like humans, monkeys tend to opt for immediate gratification. They found in hundreds of tests that the activity of a single brain cell differed depending upon whether the monkey sought immediate award or delayed one.