Thanks for that zanpar321.

This is a fascinating thread.

One thing which I have been pondering is that thiamine is essential for two enzymes, the pyruvate dehydrogenase complex and 2-oxoglutarate dehydrogenase, which play key roles in glucose metabolism, leading to production of, in effect, metabolically useful energy (ATP).

Under normal conditions glucose is the only energy source for the brain and it need to continually replenish its ATP (neuro-transmission is energetically expensive).

Naively I would have thought that if thiamine levels in the brain were abnormally low then ATP replenishment would be impaired, leading to systemic neurological effects, rather than effects which are confined to people with PD.

Does anybody know anything about this?