A common control signal and a ballistic stage can explain the control of coordinated eye-hand movements

Gopal, Atul and Murthy, Aditya (2016) A common control signal and a ballistic stage can explain the control of coordinated eye-hand movements. In: JOURNAL OF NEUROPHYSIOLOGY, 115 (5). pp. 2470-2484.

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Abstract

Voluntary control has been extensively studied in the context of eye and hand movements made in isolation, yet little is known about the nature of control during eye-hand coordination. We probed this with a redirect task. Here subjects had to make reaching/pointing movements accompanied by coordinated eye movements but had to change their plans when the target occasionally changed its position during some trials. Using a race model framework, we found that separate effector-specific mechanisms may be recruited to control eye and hand movements when executed in isolation but when the same effectors are coordinated a unitary mechanism to control coordinated eye-hand movements is employed. Specifically, we found that performance curves were distinct for the eye and hand when these movements were executed in isolation but were comparable when they were executed together. Second, the time to switch motor plans, called the target step reaction time, was different in the eye-alone and hand-alone conditions but was similar in the coordinated condition under assumption of a ballistic stage of similar to 40 ms, on average. Interestingly, the existence of this ballistic stage could predict the extent of eye-hand dissociations seen in individual subjects. Finally, when subjects were explicitly instructed to control specifically a single effector (eye or hand), redirecting one effector had a strong effect on the performance of the other effector. Taken together, these results suggest that a common control signal and a ballistic stage are recruited when coordinated eye-hand movement plans require alteration.

Item Type:	Journal Article
Publication:	JOURNAL OF NEUROPHYSIOLOGY
Publisher:	AMER PHYSIOLOGICAL SOC
Additional Information:	Copy right for this article belongs to the AMER PHYSIOLOGICAL SOC, 9650 ROCKVILLE PIKE, BETHESDA, MD 20814 USA
Keywords:	eye-hand coordination; race model; inhibitory control; ballistic stage; reaction times
Department/Centre:	Division of Biological Sciences > Centre for Neuroscience
Date Deposited:	08 Jul 2016 05:48
Last Modified:	08 Jul 2016 05:48
URI:	http://eprints.iisc.ac.in/id/eprint/54156

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