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Organization of Motor System

Huntington disease is an inherited disease that results from progressive neurodegeneration of primarily GABAergic neurons within the striatum. The most striking pathological change noted in Parkinson's disease is a loss of nerve cells in a region of the brain known as the substantia nigra, a layer of deeply pigmented gray matter located in the midbrain.

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The motor system is organized in a functional hierarchy, with each level responsible for a specific task. Movement must be planned, have a purpose, respond to sensory input, and function with coordination using spatiotemporal details of muscle positions. There are several anatomical pathways that project to the spinal cord from higher motor centers. Most of these are organized somatotopically, with movements of adjacent body parts being controlled by contiguous areas of the brain at each level within the motor hierarchy. The primary motor cortex lies in the precentral gyrus and paracentral lobule of the frontal lobe, and is responsible for controlling simple movement. It extends from the lateral fissure upward to the dorsal border of the hemisphere and beyond to the paracentral lobule. The left motor strip controls the right side of the body, and the right strip controls the left side. Neurons in the lowest lateral part of the motor strip influence the larynx and tongue, followed in upward sequence by neurons affecting the ...

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The motor system is organized in a functional hierarchy, with each level responsible for a specific task. Movement must be planned, have a purpose, respond to sensory input, and function with coordination using spatiotemporal details of muscle positions.

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