Citation

Leclercq G, Blohm G, Lefevre P. J. Neurophysiol. 2013; 110(8): 1945-1957.

Affiliation

Université catholique de Louvain.

Copyright

(Copyright © 2013, American Physiological Society)

DOI

10.1152/jn.00130.2013

PMID

23926035

Abstract

Accurate motor planning in a dynamic environment is a critical skill for humans because we are often required to react quickly and adequately to the visual motion of objects. Moreover, we are often in motion ourselves and this complicates motor planning. Indeed, the retinal and spatial motions of an object are different because of the retinal motion component induced by self-motion. Many studies investigated motion perception during smooth pursuit and concluded that eye velocity is partially taken into account by the brain. Here we investigate whether the eye velocity during ongoing smooth pursuit is taken into account for the planning of visually guided manual tracking. We had ten human participants manually track a target while in steady state smooth pursuit towards another target such that the difference between the retinal and spatial target motion directions could be large, depending both on the direction and speed of the eye. We used a measure of initial arm movement direction to quantify whether motor planning occurred in retinal coordinates (not accounting for eye motion) or was spatially correct (incorporating eye velocity). Results showed that the eye velocity was nearly fully taken into account by the neuronal areas involved in the visuomotor velocity transformation (between 75% and 102%). In particular, these neuronal pathways accounted for the non-linear effects due to the relative velocity between the target and the eye. In conclusion, the brain network transforming visual motion into a motor plan for manual tracking adequately uses extra-retinal signals about eye velocity.

Language: en