Causes
The exact cause of REM Behavior Disorder (RBD) is unknown, although the disorder may occur in association with various degenerative neurological conditions.
Rapid eye movement sleep is characterized by brain activity patterns that resemble wakefulness and a general state of atonia or muscle paralysis. Most dreaming occurs during REM sleep. In REM Behavior Disorder (RBD) the general state of muscle paralysis is lost thereby permitting a person to act out his dreams.
The basic mechanism for normal REM sleep paralysis is found in the brainstem, the part of the brain that connects the spinal cord to the cerebral hemispheres. Certain neurotransmitters, like acetylcholine (Ach), become dormant during REM sleep, thereby inhibiting muscular contractions.
In RBD, however, the neurotransmitters do not face any resistance. This causes a surge of cerebral activity. Additionally, the voluntary muscles contract, enabling ample scope for muscle movement during REM. Thus, patients of RBD begin to act out their dreams animatedly.
