I understand that the primary problem in Parkinson's Disease (PD) is an area of the brain called the substantia nigra, whose neurotransmitter is dopamine. Dopamine drugs help people with PD. In Alzheimer's Disease, the area of the brain in trouble is the hippocampus, which helps us put memory into the long term category. However, the neurons need to fire to secrete the neurotransmitter in the first place. Maybe the problem is lack of stimulation of the nerve cells, which in turn, would not secrete the dopamine and other neurotransmitters in the first place. All neurons have one thing in common: they need to fire to be healthy!