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Double dissociation between motor and visual imagery in the posterior parietal cortex
Barbara Pelgrims1, Michael Andres, Etienne Olivier
1Université catholique de Louvain, Institute of Neuroscience, Laboratory of Neurophysiology, Brussels, Belgium.
Cerebral Cortex (New York, N.Y. : 1991)
|January 27, 2009
Summary
Motor imagery (MI) and visual imagery (VI) involve distinct brain regions. Repetitive transcranial magnetic stimulation confirmed that the supramarginalis gyrus (SMG) is crucial for MI, while the superior parietal lobule (SPL) is essential for VI.
Area of Science:
- Cognitive Neuroscience
- Neuroimaging
- Human Brain Function
Background:
- Motor imagery (MI) and visual imagery (VI) may involve separate neural processes due to differing constraints.
- Neuroimaging and neuropsychological studies suggest distinct cortical networks for MI and VI.
- The superior parietal lobule (SPL) is hypothesized for VI, and the supramarginalis gyrus (SMG) for MI, but overlap exists.
Purpose of the Study:
- To investigate the distinct roles of SMG and SPL in MI and VI.
- To determine if SMG and SPL contribute to specific imagery processes or general mental rotation.
Main Methods:
- Repetitive transcranial magnetic stimulation (rTMS) was used to create temporary 'lesions' in SMG or SPL.
- Participants performed MI (hand drawing rotation) and VI (letter rotation) tasks.
Main Results:
- Lesions in SMG selectively impaired MI performance.
- Lesions in SPL selectively impaired VI performance.
- These effects were independent of stimulus angular distance.
Conclusions:
- A double dissociation between MI and VI was demonstrated, implicating SMG in motor representation reenactment and SPL in visual representation reenactment.
- SMG and SPL are specifically involved in the core processes of MI and VI, respectively, rather than general mental rotation.
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