Encoding of Reward and Physical Effort by Sensorimotor Cortical Local Field Potentials

Reward expectation in humans and animals is known to modulate behavior and its valuation is discounted by the physical effort associated with the movement. Our previous work has shown reward encoding within the macaque premotor (PMd), motor (M1), and somatosensory (S1) cortices. However, the involvement of these regions in concurrent processing of reward and effort information is not clearly understood. To address this gap, we asked how the reward representation in local field potentials (LFPs), recorded from the PMd, M1, and S1 are influenced by physical effort requirements of the motor task. We trained a nonhuman primate to perform three variations of a planar center-out reaching task: reward-only, effort-only, and reward-effort tasks. Our results showed an inverse relationship between reward-value and LFP amplitude as well as subjective influence of effort information on the reward value encoded by the LFP amplitude.