Citation

Deplancke A, Madelain L, Chauvin A, Cardoso-Leite P, Gorea A, Coello Y. J. Neurophysiol. 2010; 104(4): 2249-2256.

Affiliation

University of Lille-Nord de France.

Copyright

(Copyright © 2010, American Physiological Society)

DOI

10.1152/jn.01123.2009

PMID

20702742

Abstract

Providing evidence against a dissociation between conscious vision for perception and unconscious vision for action, recent studies have suggested that perceptual and motor decisions are based on a unique signal but distinct decisional thresholds. The aim of the present study was to provide a direct test of this assumption in a perceptual-motor dual task involving arm movements. In 300 trials, 10 participants performed speeded pointing movements towards a highly visible target located at 10 degrees from the fixation point and +/-45 degrees from to the body midline. The target was preceded by one or two close to threshold distractor(s) (80ms SOA) presented +/-30 degrees according to the target location. After each pointing movement participants judged whether the distractor was present or not on either side of the target. Results showed a robust reaction time facilitation effect and a deviation towards the distractor when the distractor was both present and consciously perceived (Hit). A small reaction time facilitation was also observed when two distractors were physically present but undetected (Double-Miss) - this facilitation being highly correlated with the physical contrast of the distractors. These results are compatible with the theory proposing that perceptual and motor decisions are based on a common signal but emerge from a contrast dependent fixed threshold for motor responses and a variable context dependent criterion for perceptual responses. This paper thus extends to arm movement control previous findings related to oculomotor control.

Language: en