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Published on: April 20, 2019
The motor cortex and its role in phantom limb phenomena.
Karen T Reilly1, Angela Sirigu
1Center for Cognitive Neuroscience, CNRS, Lyon, France.
Summary
The representation of an amputated hand does not disappear in the brain. Instead, it reorganizes, preserving motor commands crucial for the persistent phantom limb sensation.
Area of Science:
- Neuroscience
- Motor Cortex Plasticity
- Phantom Limb Phenomena
Background:
- Limb amputation leads to brain-muscle connection plasticity, with motor cortex representations seemingly vanishing.
- The persistence of phantom limbs with sensory and motor qualities contradicts the apparent disappearance of hand motor representations.
Purpose of the Study:
- To investigate the persistence of the amputated hand's representation in the primary motor cortex.
- To reconcile the apparent disappearance of motor maps with the existence of phantom limbs.
Main Methods:
- The study proposes a dual-level model of hand-movement representation in the primary motor cortex.
- This model differentiates between motor commands and muscle synergies.
Main Results:
- Reorganization in the motor cortex of upper-limb amputees primarily affects the muscular map, not the motor command map.
- The integrity of the motor command map is hypothesized to be essential for phantom limb existence.
Conclusions:
- The representation of the amputated hand persists in the primary motor cortex.
- Phantom limb phenomena are linked to the preserved motor command map, distinct from reorganized muscle synergy maps.
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