what is pppparkinson disease and what causes it?
<answer> It is nerve cells (neurons) in the brain gradually break down or die. It causes abnormal brain activity. <context> In Parkinson's disease, certain nerve cells (neurons) in the brain gradually break down or die. Many of the symptoms are due to a loss of neurons that produce a chemical messenger in your brain called dopamine.When dopamine levels decrease, it causes abnormal brain activity, leading to signs of Parkinson's disease.The cause of Parkinson's disease is unknown, but several factors appear to play a role, including:any of the symptoms are due to a loss of neurons that produce a chemical messenger in your brain called dopamine. When dopamine levels decrease, it causes abnormal brain activity, leading to signs of Parkinson's disease.