I have underestimated your scholarly value.

"I certainly don't have, as you have claimed, a simplistic knowledge of the brain. Over a period of more than ten years I wrote up twenty volumes of human biochemistry. This included the structure, reproduction and function of every single cell type in the nervous system, all of which I have detailed in what I have written. "

I would certainly like to read them. Mind sharing the publisher?

"Firstly I am nowhere near old enough to have been researching Parkinson's Disease (or anything else) for forty years. Secondly I have never applied for or received any funding, let alone billions of dollars worth."

Oh, a fellow freelancer! And a young one at that! I can understand my own obsession, being a PWP and all. What is your motivation and educational background? Biochemistry? Physics? I admit to being a freelancer there too, having studied pschology at an underfunded state university. You?

" There are a number of causes of Parkinson's Disease and a number of ways it can manifest itself, but insufficient dopaminergic activity is common to all of them. "

Ah, a point of agreement! But...

"So "neurogenesis" (cell reproduction) is completely irrelevant to Parkinson's Disease because the cells involved in Parkinson's Disease never reproduce."

...here is where I have trouble. I assume that such a hope-crushing statement is more than opinion. Medline indicates that the ball is very much in play:

"1: J Neurochem. 2007 Feb;100(3):587-95. Epub 2006 Nov 13.

Dopamine and adult neurogenesis.

Borta A, Hoglinger GU.

Experimental Neurology, Philipps University, Marburg, Germany.

Dopamine is an important neurotransmitter implicated in the regulation of mood,
motivation and movement. We have reviewed here recent data suggesting that
dopamine, in addition to being a neurotransmitter, also plays a role in the
regulation of endogenous neurogenesis in the adult mammalian brain. In addition,
we approach a highly controversial question: can the adult human brain use
neurogenesis to replace the dopaminergic neurones in the substantia nigra that
are lost in Parkinson's disease?

PMID: 17101030 [PubMed - indexed for MEDLINE]"

I vote for hope. But, then, I have Parkinson's Disease and without hope I'm a goner. Like a lot of folks, I guess.