Computational Mechanisms Mediating Inhibitory Control of Coordinated Eye-Hand Movements

Abstract

Significant progress has been made in understanding the computational and neural mechanisms that mediate eye and hand movements made in isolation. However, less is known about the mechanisms that control these movements when they are coordinated. Here, we outline our computational approaches using accumulation-to-threshold and race-to-threshold models to elucidate the mechanisms that initiate and inhibit these movements. We suggest that, depending on the behavioral context, the initiation and inhibition of coordinated eye-hand movements can operate in two modes—coupled and decoupled. The coupled mode operates when the task context requires a tight coupling between the effectors; a common command initiates both effectors, and a unitary inhibitory process is responsible for stopping them. Conversely, the decoupled mode operates when the task context demands weaker coupling between the effectors; separate commands initiate the eye and hand, and separate inhibitory processes are responsible for stopping them. We hypothesize that the higher-order control processes assess the behavioral context and choose the most appropriate mode. This computational mechanism can explain the heterogeneous results observed across many studies that have investigated the control of coordinated eye-hand movements and may also serve as a general framework to understand the control of complex multi-effector movements.

Beyond Reactive Inhibition: Unpacking the Multifaceted Nature of Motor Inhibition

“…Thus, while the computational and neural mechanisms mediating movements initiation and inhibition made with single effectors have been widely studied, much less is known when more than one effector has to be employed to respond. The review by Jana et al [18] nicely addresses such an issue, focusing on the coordination between eye and hand movements based on the results obtained using accumulation-to-threshold and race-to-threshold models. The authors suggest that the coordination of eye-hand movements follows two different modes according to the behavioral context demands.…”