ROLE OF NEURONAL OSCILLATIONS IN HUMAN THALAMUS AND SUBTHALAMIC NUCLEUS IN EVIDENCE INTEGRATION AND MOTOR EXECUTION DURING PERCEPTUAL DECISION-MAKING

Decisions and actions engage overlapping neural machinery within the basal ganglia-thalamo-cortical circuit, which transforms sensory evidence into motor output. Within this neural circuit, rhythmic neuronal oscillations in the beta (13-30 Hz) and theta (3-8 Hz) bands are thought to regulate distinct facets of decision-making and motor control. Growing evidence indicates that beta oscillations are critical for stabilizing ongoing motor states and suppress premature actions. This effect is exaggerated in Parkinson’s disease, where excessive beta oscillations are associated with rigidity and slowness of movement; and where clinical treatments that reduce beta, such as deep brain stimulation (DBS), can cause impulsive responding. In contrast, theta oscillations are believed to signal decision conflict and guide dynamic adjustments of the amount of evidence needed for a decision, shaping the trade-off between speed and accuracy. To probe these mechanisms directly, we recorded local field potentials (LFPs) from the thalamus and the subthalamic nucleus in patients undergoing awake DBS surgery while they performed a perceptual decision-making task (14 patients, 11 bilateral surgeries, 25 datasets in total). The task was a reaction time version of the random dot motion task in which the stimulus terminated when patients made a decision, or a 4-second deadline had passed. Initial analyses indicate that the functions of beta and theta oscillations are multifaceted, with, for example, beta oscillations around motor execution being modulated by evidence strength. By linking neuronal dynamics to trial-by-trial decision and motor parameters, our work aims to bridge neurocomputational accounts of decision-making and motor control.
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