Research Summary

The Neural Mechanisms of Decision Making for Coordinated Eye-Hand Movements

Effective interactions with the dynamic world around us require the ability to coordinate between movements of the eyes and limbs, and to inhibit such movements whenever any change in the context makes the action inappropriate. In an uncertain situation, how we select an object and control the corresponding action on it is still not thoroughly understood.

In this project, we will test the hypothesis that the perceptual and motor decisions evolve simultaneously in the primate brain even when execution of an action is uncertain. Humans and monkeys will perform a pair of novel ‘choicecountermanding’ tasks that require selection of the endpoint of their eye and/or reach movement(s) by discriminating visual features of either a central or peripheral cue, and inhibit the impending action in response to an infrequent visual stop-signal. Comparison of performance, response times, and attention related modulation of EEG signals in different task conditions will help us to understand the dynamics of target selection and action planning. Simultaneously recorded spiking activity and local field potentials of neurons in the frontal eye field (FEF) and lateral intra-parietal (LIP) area of monkeys will be examined for synchrony and causality. Activity of recorded neurons and the simulated Bayesian neurons, which emit spikes when the integrated sensory evidence filtered by the internal representation of a rule exceeds the predicted likelihood of the response, will be compared to understand the computations in this network. The outcome of this project will improve our understanding of the functional role of parietal and frontal cortices in eye-hand coordination and decision making.