brain, spinal cord, and nerve disorders
Multiple System Atrophy (MSA)
Causes of Multiple System Atrophy
Multiple system atrophy results from degeneration of several parts of the brain and spinal cord: Thebasal ganglia(collections of nerve cells at the base of the cerebrum, deep within the brain), which help control voluntary muscle movements by balancing the actions of muscle groups that move the same muscles in opposite ways (for example, a group that bends an arm and a group that straightens the arm) Thecerebellum,which coordinates voluntary movements (particularly complex movements done simultaneously) and helps maintain balance Areas that control the autonomic nervous system,which regulates involuntary body processes, such as how blood pressure changes in response to changes in posture The cause of the degeneration is unknown, but degeneration in multiple system atrophy probably results when alpha-synuclein changes shape (misfolds) and accumulates in support cells in the brain. Alpha-synuclein is a protein in the brain that helps nerve cells communicate, but whose function is not yet fully understood. Abnormal alpha-synuclein can also accumulate in people with Pure Autonomic Failure , Rapid eye movement sleep behavior disorder often occurs in people with disorders that involve accumulation of alpha-synuclein, including multiple system atrophy. Thecerebellumis located below the cerebrum just above the brain stem. The cerebellum coordinates the body’s movements. With information it receives from the cerebral cortex and the basal ganglia about the position of the limbs, the cerebellum helps the limbs move smoothly and accurately. (The cerebral cortex is the convoluted layer of tissue that forms the outer surface of the cerebrum. It contains most of the nerve cells in the nervous system.) Thebasal gangliaare collections of nerve cells located deep within the brain. They include the following structures: Caudate nucleus (a C-shaped structure that tapers to a thin tail) Putamen Globus pallidus (located next to the putamen) Subthalamic nucleus Substantia nigra The basal ganglia help smooth out muscle movements and coordinate changes in posture. 