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Updated: Aug 8, 2026
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Methods to Explore the Influence of Top-down Visual Processes on Motor Behavior
Published on: April 16, 2014
No double-dissociation between optic ataxia and visual agnosia: multiple sub-streams for multiple visuo-manual
L Pisella1, F Binkofski, K Lasek
1INSERM UMR-S 534, Institut National de la Santé et de la Recherche Médicale, and Université Claude Bernard-Lyon, Espace et Action, Bron, France.
Neuropsychologia
|June 7, 2006
Summary
The dominant view of separate visual perception and action streams is challenged. Evidence suggests multiple parallel pathways, not a simple double-dissociation, underlie complex visual-motor control.
Area of Science:
- Neuroscience
- Cognitive Science
- Neuropsychology
Background:
- The traditional view posits distinct ventral (perception) and dorsal (action) visual streams.
- Visual agnosia (VA) and optic ataxia (OA) have been used to support this dichotomic model, linked to ventral and dorsal damage, respectively.
Purpose of the Study:
- To critically evaluate the empirical data supporting the double-dissociation between VA and OA.
- To propose a more complex model of visual-to-motor pathways based on neuropsychological and monkey data.
Main Methods:
- Review of existing human neuropsychology and monkey data.
- Analysis of patient deficits in visual agnosia and optic ataxia.
- Examination of evidence for multiple parallel visual-to-motor connections.
Main Results:
- Empirical data are insufficient to support a strict double-dissociation between OA and VA.
- Evidence points to at least three parallel visual-to-motor pathways: dorso-dorsal, ventral-prefrontal, and ventro-dorsal.
- Each pathway has distinct roles in immediate, mediate, and complex visuo-motor control, with specific associated deficits.
Conclusions:
- The organization of visual-to-motor processing is more complex than a simple perception-action dichotomy.
- Understanding differential temporal constraints and integrative capabilities of these parallel pathways is key to interpreting neuropsychological deficits.
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