Researchers are pretty sure that these knots, called senile plaques, and neurofibrillary tangles cause mental deterioration. This is one way the disease can be diagnosed. Because of this abnormality in the cerebral cortex, memory and reasoning are among many other functions that are effected by this disease. Disease is caused by a large loss of dopamine in the brain. Dopamine is a neurotransmitter that transmits messages to the stiatum, which initiates smooth movement and balance.
Dopamine works with acetylcholine in the brain to maintain steady movement.
Because of the dopamine shortage in Parkinson's patients, the balance is thrown off because the same amount of acetylcholine is maintained. Huntington's Disease was discovered in 1872. It is caused by a loss of cells in the basal ganglia. Patients with this disease lose the ability to organize, cope with new situations, reason, think, talk, walk, swallow, etc. The disease ends in death, usually by infection, choking, or heart failure.