I think I’m trolling myself, because I’ve been putting money into the fidelity index funds because after my reading that’s the kind of fund I thought dca applied to. Is it better to go for one of these etf instead? Is it more efficient because of lack of an expense ratio

Unfortunately, dopamine isn’t able to cross the blood brain barrier. The way PD is treated involves use of levodopa (dopamine precursor) in combination with carbidopa (decarboxylase inhibitor;prevents metabolism of levodopa to help it cross the BBB). The nigrostriatal pathway is the dopamine pathway affected in pd, and through this pathway you get your basal ganglia dopamine responsive pathways that modulate motor activity. But in PD these pathways get disrupted so the dopamine system that applies the brakes beats out the pathway applying the gas. I’m very adhd and I suck at explaining things but would be happy to elaborate further! I do have to say there are some very cool therapies in the works for pd, I’m particularly excited about gene therapy