Neurons in the primate amygdala may be involved in planning for future rewards, reports a study published online in Nature Neuroscience. The amygdala, a part of the brain usually associated with fear and aggression, is known to be involved in reward-related behaviors. However, this study demonstrates its involvement in a task involving long-term planning for reward, a function usually attributed to the cerebral cortex.
Fabian Grabenhorst and colleagues studied non-human primates in a task in which they chose to consume rewards or save them across trials, with saved rewards earning interest as the task progressed. Like savvy investors, the monkeys tended to save their rewards when interest rates were high, saving less when interest rates were low. Recordings from neurons in the amygdala showed that, as monkeys saved, those amygdalar neurons showed patterns of activity that reflected the number of trials over which the monkey would save, even before the monkey had enacted this plan. The level of such “planning activity” in amygdala neurons was predictive of how efficient monkeys were at saving rewards. These findings suggest that the amygdala, thought to be involved only in rather primitive behaviours, may play a role in higher cognitive functions as well.