Experimental Brain Research

, Volume 188, Issue 3, pp 371–378

Online corrections can produce illusory bias during closed-loop pointing

Research Article

DOI: 10.1007/s00221-008-1367-z

Cite this article as:
Ehresman, C., Saucier, D., Heath, M. et al. Exp Brain Res (2008) 188: 371. doi:10.1007/s00221-008-1367-z


This experiment examined whether the impact of pictorial illusions during the execution of goal-directed reaching movements is attributable to ocular motor signaling. We analyzed eye and hand movements directed toward both the vertex of the Müller–Lyer (ML) figure in a closed-loop procedure. Participants pointed to the right vertex of a visual stimulus in two conditions: a control condition wherein the figure (in-ML, neutral, out-ML) presented at response planning remained unchanged throughout the movement, and an experimental condition wherein a neutral figure presented at response planning was perturbed to an illusory figure (in-ML, out-ML) at movement onset. Consistent with previous work from our group (Heath et al. in Exp Brain Res 158:378–384, 2004; Heath et al. in J Mot Behav 37:179–185, 2005b), action-bias present in both conditions; thus illusory bias was introduced into during online control. Although primary saccades were influenced by illusory configurations (control conditions; see Binsted and Elliott in Hum Mov Sci 18:103–117, 1999a), illusory bias developed within the secondary “corrective” saccades during experimental trials (i.e., following a veridical primary saccade). These results support the position that a unitary spatial representation underlies both action and perception and this representation is common to both the manual and oculomotor systems.


Illusion Saccade Pointing Müller–Lyer Closed-loop 

Copyright information

© Springer-Verlag 2008

Authors and Affiliations

  1. 1.Canadian Centre for Behavioural NeuroscienceUniversity of LethbridgeLethbridgeCanada
  2. 2.School of KinesiologyUniversity of Western OntarioLondonCanada
  3. 3.Faculty of Health and Social DevelopmentUniversity of British ColumbiaKelownaCanada