Citation

Brown LE, Marlin MC, Morrow S. J. Neurophysiol. 2014; 113(2): 409-419.

Affiliation

Trent University.

Copyright

(Copyright © 2014, American Physiological Society)

DOI

10.1152/jn.00005.2014

PMID

25339706

Abstract

Performance is often improved when targets are presented in space near the hands rather than far from the hands. Performance in near-hand space may be improved because participants can use proprioception from the nearby limb and hand to provide a narrower and more resolute frame of reference. An equally-compelling alternative is that targets appearing near the hand fall within the receptive fields of visual-tactile bimodal cells, recruiting them to assist in the visual representation targets that appear near but not far from the hand. We distinguished between these two alternatives by capitalizing on research showing that vision and proprioception have differential effects on the precision of target representation (Van Beers et al., 1998). Participants performed an in-to-centre reaching task to an array of central target locations with their right hand while their left hand rested near (beneath) or far from the target array. Reaching end-point accuracy, variability, time and speed were assessed. We predicted that if proprioception contributes to the representation of near-hand targets, error variability in depth will be smaller in the hand-near condition than in the hand-far condition. By contrast, if vision contributes to the representation of near-hand targets, error variability along the lateral dimension will be smaller in the hand-near than in the hand-far condition. Our results showed that placing the hand near the targets reduced end-point error variability along the lateral dimension only. The results suggest that near-hand targets are represented with greater visual resolution than far targets.

Language: en