Decoding the neural dynamics of oculomotor decision making in humans

Summary Freely choosing an action between alternatives activates a widely distributed decision circuit in the brain. Primate studies suggest that oculomotor decision processes are encoded by high-frequency components of local field potentials (LFPs) recorded in frontal and parietal areas. To what extent these LFP observations extend to oculomotor decision-making in humans is unknown. Here, we address this question using intracerebral EEG recordings from 778 sites across six surgical epilepsy patients. Free saccade choices were associated with sustained high gamma (60-140 Hz) activity during the delay period in prefrontal and parietal areas. Importantly, employing single-trial signal classification to contrast free, instructed and control trials, we were able to isolate decision-related activity from sensory and motor processes. Our findings provide the first direct electrophysiological evidence in humans for the role of high gamma activity in parietal and prefrontal areas in the intrinsically driven process of choosing among competing behavioral alternatives during free choice. Highlights First LFP recordings in humans performing an oculomotor decision-making task Free-choice saccade trials exhibit sustained frontoparietal high gamma activity Machine learning analytics unravel underlying spectral and temporal brain dynamics Single-trial saccade-locked gamma distinguish planning and execution processes