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Two distinct ipsilateral cortical representations for individuated finger movements
Jörn Diedrichsen1, Tobias Wiestler, John W Krakauer
1Institute of Cognitive Neuroscience, University College London, London, UK. j.diedrichsen@ucl.ac.uk
Cerebral Cortex (New York, N.Y. : 1991)
|May 22, 2012
Summary
The brain
Area of Science:
- Neuroscience
- Motor Control
- Brain Imaging
Background:
- Upper limb movements are primarily controlled by the contralateral hemisphere.
- The functional significance of ipsilateral motor cortex activity during unimanual movements is not well understood.
Purpose of the Study:
- To investigate the functional significance of ipsilateral motor cortex representations during unimanual and bimanual movements.
- To analyze neural finger representations using fine-grained activation patterns in human functional imaging.
Main Methods:
- Functional magnetic resonance imaging (fMRI) was used to study neural activity.
- Analysis focused on fine-grained activation patterns during single isometric finger presses.
- Differences in neural representations during unimanual versus bimanual actions were compared.
Main Results:
- Primary motor and sensory cortices exhibit finger-specific ipsilesional representations during unimanual movements, mirroring contralateral actions.
- These ipsilesional representations disappear during bimanual actions.
- Caudal premotor and anterior parietal cortices show a distinct, context-dependent ipsilesional representation during bimanual actions.
Conclusions:
- Ipsilateral cortical representations are context-dependent, changing their informational content and functional role.
- The findings suggest a mechanism for coordinating bimanual movements involving modulation of contralateral action representations.
- Ipsilesional activity during unimanual movements may result from input to otherwise idle circuits from the contralateral hemisphere.
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