FWIW, four of the metals listed (copper, zinc, magnesium, iron) are part of cytochrome c oxidase (CCO), which is a critical part (terminal element) of the electron transport chain in mitochondria. Given that the brain uses a lot of energy (which I would guess to be from the progressive ion cascade that accompanies neural signal transmission) it's unsurprising that a lot of these end up in the brain.

I've been reading studies/reviews on AD for the last few decades (since my mom was diagnosed) and the etiology (theory of how the disease occurs) I find most convincing is Francisco Gonzalez-Lima's hypothesis of AD as a vascular / metabolic disease. He's done some interesting work both in using low dose methylene blue (MB) and IR transcranial lasers to 'donate' electrons (or photons acting as electrons) to act in place of CCO and so slow progressive neuronal loss.

I thought there might be similar work with MB and Parkinson's. Turns out there is: Methylene blue protects dopaminergic neurons against MPTP-induced neurotoxicity by upregulating brain-derived neurotrophic factor — and it seems to increase brain derived neurotropic factor (a signal to grow more neurons).