Romeo et al. report [1]:
"The rats exposed to bright light for 20 days or 90 days showed a relatively greater number of neuromelanin-positive neurons. Surprisingly, TH-positive neurons decreased progressively in the substantia nigra reaching a significant 29% reduction after 90 days of continuous bright light exposure. This decrease was paralleled by a diminution of dopamine and its metabolite in the striatum. Remarkably, in preliminary analysis that accounted for population density, the age and race adjusted Parkinson's disease prevalence significantly correlated with average satellite-observed sky light pollution."
Reference

The epidemiology is a spatial correlation between light pollution and Parkinson's prevalence in the US, the Willis paper: a technique seen here before.

Clearly, if there is a causal relationship between light and PD, there are implications for sleep and the use of computers etc..

Perhaps, and this is just my speculation, this helps to explain the increase of PD over time as we follow natural light patterns less and less.

It doesn't explain the high prevalence of PD in the Amish communitity (see Rick's thread).

Reference

[1] "Bright light exposure reduces TH-positive dopamine neurons: implications of light pollution in Parkinson's disease epidemiology"
Stefania Romeo,Cristina Viaggi,Daniela Di Camillo,Allison W. Willis,Luca Lozzi,Cristina Rocchi,Marta Capannolo,Gabriella Aloisi,Francesca Vaglini,Rita Maccarone,Matteo Caleo,Cristina Missale,Brad A. Racette,Giovanni U. Corsini,Roberto Maggio
Nature, March 2013
http://www.nature.com/srep/2013/1303...srep01395.html

John

and so we wanted Parkinson's research to try something new. This is one of the most fall-off-your-chair research papers I have ever seen. Read the whole thing; I skip over some of the heavier science stuff because it lacks narrative and I don't know much about science, but in every paragraph where they are explaining things, there are sentences that jump out at you. Things I would never imagined. The lighting? OMG.
That's not just thinking outside the box, that's thinking right off the planet. That kind of creativity in science is a marvel to behold. Let's keep track of these people and make sure they get a fair hearing in the PD research world.

submariners spend months under 100% artificial light, do they have a higher incidence of pd? what about those living in the far north with months of darkness and also under 100% artificial light?
wonder what inspired these researchers to open this can of worms.

i have always assumed pd distribution in the u.s is somewhat removed from the causitive factors since numbers often taken from medicare statistics and as people age they often move to the city and/or warmer climates.

…Although light with longer wavelengths penetrates into the brain more effectively, shorter wavelength light can also penetrate into deep brain structures and regulate, for example, the seasonal cycle of reproduction in birds..,. Penetration of light into the brain has also been demonstrated in larger animals, including sheep and dog…

…light penetrating into the substantia nigra could be the source of oxidative stress. Light could oxidise dopamine and, in turn, induce the formation of neuromelanin, and cause dopamine neuron degeneration...

….animals continuously exposed to bright light for 3 months showed a significant decrease in dopamine (33%) and DOPAC (44%) ….

….the effect of light on dopamine neuron is strictly dependent on the wavelength used and the time of exposure….

…whether the reduction in TH-positive neurons produced by continuous exposure to light was induced by a direct effect of light on the substantia nigra or whether it was indirectly produced by the stress caused by retina activation (i.e. the complete alteration of the circadian rhythm). Continuous bright light profoundly alters the circadian cycle of the animals and their hormonal homeostasis…

One would suspect that the amount of light that reaches the substantia nigra in the human brain—for the size of the head, the thickness of the skull and the deep brain localization of the substantia nigra—will be negligible. However, scientific data refutes that assumption…. a tiny amount of light can reach deep brain structures in human beings and this amount is proportional to the length of exposure and the brightness of the light source….

…these observations suggest that artificial light rather than sunlight could play a role in Parkinson's disease,….

the spectral characteristics of artificial light, especially fluorescent light, are completely different from sunlight, as the sunlight spectrum is continuous while fluorescent light spectrum is discontinuous and shows several peaks. Light frequencies of the sunlight spectrum could protect rather than damage the dopamine neurons…

…the concept of plurifocal illness in Parkinson's disease is absolutely questionable since it is linked to the diagnostic purity….

AND THE FINAL PAGE OF THE STUDY SAYS:
Competing financial interests
The authors declare no competing financial interests.
Corresponding author
Correspondence to:
• Roberto Maggio
This work is licensed under a Creative Commons Attribution-Non-Commercial-NoDerivs 3.0 Unported License. To view a copy of this license, visit http://creativecommons.org/licenses/by-nc-nd/3.0/

bob, were're all entitled to our opinions.

if research on rats could always be transferred 100% to humans we would have been "cured" and/or have stopped progression years ago. a lot of pd trials of something that worked in rats have failed in humans.

so i'm not going to take any study on rats too seriously. especially when you can't get a sun tan from a normal fluorescent bulb. and a tan is from producing melanin.

they can grow human dopamine neurons in a petri dish, derived from skin cells from someone with pd. they could test their theory on them but what if the artificial light did inhibit dopamine production, what would you do with that info? it's still a very unnatural situation.


http://en.wikipedia.org/wiki/Melanin

Oh dear, I found many double negatives in the presentation of this study and got lost. Would anyone have the energy to make a summary.

One thing that stood out to me- weren't the researchers definitively stating that near infrared light has the ability to protect dopamine neurons. If this is the case shouldn't we all be getting treatment with that. I have a FAR (not near) infrared sauna- what's the difference in wave length? This is something we all could be doing.

A few other thoughts I had.

When studying botany, way back in the day, I remember hearing that plants growth was correlated not so much the exposure length of the daylight hours but rather the number of hours of darkness it was exposed to.

Finally,

I developed cataracts very young -in my early 40's. Was that an protective
response of mt body to a harmful amount or type of light?

What an interesting article! Light penetrates the brain!!!??!!

[QUOTE=soccertese;966220]bob, were're all entitled to our opinions. Quote.

yes, in your opinion it is questionable why these scientists opened a can of words. In my opinion, it is excellent, at least as far as cans of worms go.

Quote: if research on rats could always be transferred 100% to humans we would have been "cured" and/or have stopped progression years ago... a lot of pd trials of something that worked in rats have failed in humans....
so i'm not going to take any study on rats too seriously.... quote

It is true that if we were mice, we would have been cured of everything by now. But they can't try anything on humans without trying it mice and rats; then primates, then us

they can grow human dopamine neurons in a petri dish,
and expose the petri dish to constant light for 90 days?

quote: what if the artificial light did inhibit dopamine production, what would you do with that info?quote

As they say in the study, lighting could be changed. I personally attended a sales pitch made to real estate developers from some company in California that was marketing flourescent tubes that they claimed matched the spectrum of sunlight, and they claimed that it was healthier. That was in the late 1980's. They went bankrupt because they were more expensive, and so the real estate companies did not buy them

This study may go nowhere. But it is one of the few that is not just repeating all the others.

Dear Roberto Maggio,

Your study of light and Parkinson's is one of the most exciting studies I have heard in years.

A discussion is taking place here: http://neurotalk.psychcentral.com/thread185478.html

(We all have Parkinson's) (Some are "citizen scientists"). The forum is influential in the Parkinson's community.

Please drop by and have a look. And it would be awesome if you or one or more of your colleagues would join our Neurotalk, answer questions, inform; discuss; take down the walls that exist in the Parkinson's world.

Roberto Maggio <roberto.maggio@univaq.it>

Dear Bob,
thank you for the E-mail.
I will be pleased to register in the forum.
Best regards
Roberto Maggio

I was unaware of it until I came across the paper on which this thread is based that there was a large literature linking exposure to artificial light to health problems. To supplement the paper, let's look at two of these that point indirectly at Parkinson's.

Parkinson's associated with melanoma. [1]
Melanoma associated with artificial light. [2]
Parkinson's associated with prostate cancer. [1]
Prostate cancer associated with artificial light. [3]
References

[1] "Study Examines Association Between Parkinson Disease, Cancer"
Sep 3, 2012
http://www.sciencedaily.com/releases...0903221130.htm

[2] "Are some melanomas caused by artificial light?"
Are some melanomas caused by artificial light?
Marina Kvaskoff, Philip Weinstein
http://www.ncbi.nlm.nih.gov/pubmed/20347530

[3] "Light linked to prostate cancer "
Feb 3, 2009
http://www.upi.com/Health_News/2009/...4881233680656/

John

Very interesting.

I do know that fluorescent lights can trigger migraine headaches. Also, all the exposure to light from electronic screens makes one wonder what harm is being done to our brains. And good sleep hygiene (and we all know how important sleep is) requires total darkness, with limited exposure to bright lights prior to retiring.