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When does action resist visual illusion? The effect of Müller-Lyer stimuli on reflexive and voluntary saccades.
Exp Brain Res. 2007 Aug; 181(2):277-87.EB

Abstract

The primate visual cortex exhibits two anatomically distinct pathways (dorsal and ventral). According to the "two visual systems hypothesis" (TVSH) of Milner and Goodale (The visual brain in action. Oxford University Press, Oxford, 1995), this anatomical distinction corresponds to a functional division of labor between vision-for-action (dorsal) and vision-for-perception (ventral). This proposal is supported by evidence that, in healthy volunteers, perceptual responses are affected by visual illusions, whereas motor responses to the same illusion-inducing stimuli are not. However, previously we have shown that the amplitude of saccadic eye movements is modified by the Müller-Lyer illusion in a similar manner as perceptual responses. Here we extend this finding to reflexive and voluntary (memory-guided) saccades. We show that both types of saccade can be strongly affected by the illusion. In our studies, the effect on reflexive saccades was comparable to that usually observed with verbal reports (an effect size of 22 +/- 8%), whereas the effect on voluntary saccades was smaller (11 +/- 11%). In addition, both types of saccade provide evidence for the scaling bias usually observed in perceptual responses. We suggest that previous studies may have employed methods that generally reduced the effect of the illusion. Interpretations of dissociations between reflexive and voluntary saccades in terms of the TVSH appear to be premature.

Authors+Show Affiliations

Division of Orthoptics, University of Liverpool, Thompson Yates Building, Brownlow Hill, Liverpool, UK. pcknox@liv.ac.ukNo affiliation info available

Pub Type(s)

Journal Article

Language

eng

PubMed ID

17372725

Citation

Knox, Paul C., and Nicola Bruno. "When Does Action Resist Visual Illusion? the Effect of Müller-Lyer Stimuli On Reflexive and Voluntary Saccades." Experimental Brain Research, vol. 181, no. 2, 2007, pp. 277-87.
Knox PC, Bruno N. When does action resist visual illusion? The effect of Müller-Lyer stimuli on reflexive and voluntary saccades. Exp Brain Res. 2007;181(2):277-87.
Knox, P. C., & Bruno, N. (2007). When does action resist visual illusion? The effect of Müller-Lyer stimuli on reflexive and voluntary saccades. Experimental Brain Research, 181(2), 277-87.
Knox PC, Bruno N. When Does Action Resist Visual Illusion? the Effect of Müller-Lyer Stimuli On Reflexive and Voluntary Saccades. Exp Brain Res. 2007;181(2):277-87. PubMed PMID: 17372725.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - When does action resist visual illusion? The effect of Müller-Lyer stimuli on reflexive and voluntary saccades. AU - Knox,Paul C, AU - Bruno,Nicola, Y1 - 2007/03/20/ PY - 2006/05/31/received PY - 2007/02/26/accepted PY - 2007/3/21/pubmed PY - 2007/12/6/medline PY - 2007/3/21/entrez SP - 277 EP - 87 JF - Experimental brain research JO - Exp Brain Res VL - 181 IS - 2 N2 - The primate visual cortex exhibits two anatomically distinct pathways (dorsal and ventral). According to the "two visual systems hypothesis" (TVSH) of Milner and Goodale (The visual brain in action. Oxford University Press, Oxford, 1995), this anatomical distinction corresponds to a functional division of labor between vision-for-action (dorsal) and vision-for-perception (ventral). This proposal is supported by evidence that, in healthy volunteers, perceptual responses are affected by visual illusions, whereas motor responses to the same illusion-inducing stimuli are not. However, previously we have shown that the amplitude of saccadic eye movements is modified by the Müller-Lyer illusion in a similar manner as perceptual responses. Here we extend this finding to reflexive and voluntary (memory-guided) saccades. We show that both types of saccade can be strongly affected by the illusion. In our studies, the effect on reflexive saccades was comparable to that usually observed with verbal reports (an effect size of 22 +/- 8%), whereas the effect on voluntary saccades was smaller (11 +/- 11%). In addition, both types of saccade provide evidence for the scaling bias usually observed in perceptual responses. We suggest that previous studies may have employed methods that generally reduced the effect of the illusion. Interpretations of dissociations between reflexive and voluntary saccades in terms of the TVSH appear to be premature. SN - 0014-4819 UR - https://www.unboundmedicine.com/medline/citation/17372725/When_does_action_resist_visual_illusion_The_effect_of_Müller_Lyer_stimuli_on_reflexive_and_voluntary_saccades_ L2 - https://dx.doi.org/10.1007/s00221-007-0927-y DB - PRIME DP - Unbound Medicine ER -