Light pollution as a cause of PD?!? Seems crazy, and this study was on rats- take it with a grain of salt, right? Take a look at that epidemiology map we know so well sized up against a light pollution map (fig 6). It is somewhat intriguing given that it is mainly the pigmented neurons in our brains are hit hardest in the locus coereleus and substantia nigra.

This provides a strong epidemiological argument that our pineal gland is key to unlocking the mystery of PD. Here is a short list of other findings supporting the role of neuromelanin (produced by the pineal gland):

PMCID: PMC3589725
Bright light exposure reduces TH-positive dopamine neurons: implications of light pollution in Parkinson's disease epidemiology

Essentially they are saying that artificial light exposure results in production of too much dopamine and in turn like six times more neuromelanin and cellular oxidation leading to cell death.

Other evidence:

Iron is essential for changing dopamine to neuromelanin. The
PD brain has an over abundance of this too.

As a matter of fact, iron is most abundant in areas that are rich in dopaminergic neurons, namely the globus pallidus, putamen, and substantia nigra of the basal ganglia.

Evidence that light therapy (blue light) is effective in PD (in studies) because it suppresses melanin production.

Research now showing there are seasonal fluctuations to dopa levels produced and hints that our season of birth may prime us for PD later in life.

This has intriguing implications as to why are all susceptible to Vitamin D deficiency, doesn't it?

Any other thoughts? Rick does this show correlation to latitude?