Gharesi, N. | bioRxiv Science

bioRxiv2026

Neural Signatures of Post-Decision Outcome Expectation and Evaluation in Human Sensorimotor Choice Behavior

The concept of embodied sensorimotor decision-making proposes that processes implicated in evaluating sensory inputs and selecting appropriate motor actions unfold partly in cortical regions traditionally associated with movement planning and execution. Reinforcement learning models emphasize the role of reward prediction error (RPE) in optimizing action selection based on decision outcome feedback. However, most evidence for the existence of RPE signals locates them in midline frontal and parietal cortex, and comes from tasks with externally manipulated reward probabilities that create artificial prediction errors. Whether RPE signals are expressed in human cortical motor areas during deterministic (non-probabilistic) tasks remains unclear, and would provide further support for embodied decision-making. We used magnetoencephalography (MEG) to study post-decision neural dynamics in a color discrimination task in selected cortical regions of interest (ROIs). Participants had to press buttons with their left or right index finger in response to checkerboard stimuli with different levels of color evidence for the correct choice. Outcomes were fully determined by participants choices. Delayed auditory feedback veridically indicated whether their hand choice was correct or not. We observed a robust beta-band (15-29 Hz) rebound after correct outcome feedback, strongest in ventral and dorsal premotor, anterior cingulate and superior parietal ROIs as well as occipital and auditory ROIs, and weakest in the primary motor and somatosensory ROIs. Critically, the rebound magnitude after correct feedback scaled inversely with color evidence strength and associated decision error rates. It was minimal in strong-evidence trials ([~]0.1% errors) and maximal in weak-evidence trials ([~]34% errors), resembling a context-sensitive positive RPE signal that was strongest when a correct outcome was least expected. Alpha-band (8-12 Hz) post-feedback rebound increases in weak evidence trials were not as strong as in the beta band and appeared mainly in occipital, superior parietal and posterior cingulate ROIs. After the decision but before feedback, both beta and alpha band power showed sensitivity to the level of sensory evidence on which the decisions had been based, with reduced post-movement rebound or enhanced suppression in trials with weak evidence--suggestive of internally generated outcome expectations. Pre-feedback alpha rebound suppression was strongest in occipital, superior parietal and posterior cingulate ROIs. Pre-feedback beta rebound suppression was not as strong. Together, these findings reveal distinct beta- and alpha-band dynamics that reflect internal pre-feedback outcome expectations and feedback-driven RPE-like outcome assessments. They support distributed cortical mechanisms, including premotor, parietal and cingulate regions, in reward expectation, outcome evaluation, and adaptive control, highlighting a role for motor and associative cortices in embodied decision-making, performance monitoring, and flexible behavior under uncertainty.

neuroscience↗

bioRxiv2023

Evaluation of abstract rule-based associations in the human premotor cortex during passive observation

Decision-making often manifests in behavior, typically yielding overt motor actions. This complex process requires the registration of sensory information with ones internal representation of the current context, before a categorical judgment of the most appropriate motor behavior can be issued. The construct concept of embodied decision-making encapsulates this sequence of complex processes, whereby behaviorally salient information from the environment is represented in an abstracted space of potential motor actions rather than only in an abstract cognitive "decision" space. Theoretical foundations and some empirical evidence account for support the involvement of premotor cortical circuits in embodied cognitive functions. Animal models show that premotor circuits participate in the registration and evaluation of actions performed by peers in social situations, that is, prior to controlling ones voluntary movements guided by arbitrary stimulus-response rules. However, such evidence from human data is currently limited. Here we used time-resolved magnetoencephalography imaging to characterize activations of the premotor cortex as human participants observed arbitrary, non-biological visual stimuli that either respected or violated a simple stimulus-response association rule. The participants had learned this rule previously, either actively, by performing a motor task (active learning), or passively, by observing a computer perform the same task (passive learning). We discovered that the human premotor cortex is activated during the passive observation of the correct execution of a sequence of events according to a rule learned previously. Premotor activation also differs when the subjects observe incorrect stimulus sequences. These premotor effects are present even when the observed events are of a non-motor, abstract nature, and even when the stimulus-response association rule was learned via passive observations of a computer agent performing the task, without requiring overt motor actions from the human participant. We found evidence of these phenomena by tracking cortical beta-band signaling in temporal alignment with the observation of task events and behavior. We conclude that premotor cortical circuits that are typically engaged during voluntary motor behavior are also involved in the interpretation of events of a non-ecological, unfamiliar nature but related to a learned abstract rule. As such, the present study provides the first evidence of neurophysiological processes of embodied decision-making in human premotor circuits when the observed events do not involve motor actions of a third party.

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