The Role of Frontal Eye Field in Saccadic Mixed-strategy Decision-making

Game theory can predict the distribution of choices in aggregate during mixed-strategy games, yet the neural process mediating individual probabilistic choices remains poorly understood. Here, we examined the role of frontal eye field (FEF) in a decision-making task when macaques were trained to play a mixed-strategic game - Matching Pennies - against a computer opponent. Neuronal activities of FEF neurons predicted the animals upcoming saccadic choices and these activities became increasingly more selective as the choice deadline approached. Subthreshold electrical micro-stimulation applied in FEF also biased choices. Extended stimulation biased choices towards the preferred FEF vector whereas early termination of stimulation biased choices away from the preferred FEF vector. By contrast, micro-stimulation biased choices in the preferred direction during a non-strategic perceptual luminance discrimination task. We conclude that FEF is causally contributing to mixed-strategy decision-making process although the timing of FEF activation contributes to the decision process in a more non-linear manner during strategic compared to perceptual decision-making.