Neural dynamics underlying self-control in the primate subthalamic nucleus

Abstract

The subthalamic nucleus (STN) is hypothesized to play a central role in neural processes that regulate self-control. Still uncertain, however, is how that brain structure participates in the dynamically evolving representation of value that underlies the ability to delay gratification and wait patiently for a gain. To address that gap in knowledge, we studied the spiking activity of neurons in the STN of monkeys during a task in which animals were required to remain motionless for varying periods of time in order to obtain food reward. At the single-neuron and population levels, we found a cost-benefit integration between the desirability of the expected reward and the imposed delay to reward delivery, with STN signals that dynamically combined both attributes of the reward to form a single integrated estimate of value. This neural representation of subjective value evolved dynamically across the waiting period that intervened between instruction cue and reward delivery. Moreover, this representation was gradually distributed along the antero-posterior axis of the STN such that the most posterior-placed neurons represented the temporal discounting of value most strongly. These findings highlight the selective involvement of the posterior STN in a dynamic internal process that dynamically estimates the ongoing cost-benefit balance of the current context. Such a process is essential for self-control, promoting goal pursuit and the willingness to bear the costs of time delays.