The brain isn’t designed to get light in to it. If your
brain is receiving light; there’s a hole in your head.
That’s not healthy!
The brain was not designed.
There are a number of holes in your skull and your ears are two of them.
Whether or not the brain reacts to light is either proven or disproven depending on whether you find a flaw in this research or can conduct research that finds against it.
Years ago I came across an article proposing that the eye first originated as a photosensitive cell in the mass of the brain. At first the cell was binary, it detected light or darkness, and its function had some positive role in the survival of the organism that possessed it. As time passed the cell became specialized and was relocated closer to the skin.
Light penetrates skin, tendon, and bone, albeit in ever smaller amounts. It is not impossible that the brain reacts to light.
I haven't read all of the comments here, but I come from a pretty good neuroscience background and have some thoughts on why this looks like baloney. It's about the way the brain works. The brain itself is not a sensory organ. It processes signals from sensory organs. Information reaches the eye or the skin or the tongue as mechanical, chemical, and optical data but then get transduced into an electrical impulse. Even if there were light receptors in the brain, it's highly unlikely that they would be so specific that activating them would cause positive feelings. That's how information gets processed at the level of our senses, but not in our brains. Individual neurons do not hold individual memories. Nor do they seem to control specific emotions.
If shining light on the brain actually changed the levels of activity, it would have an impact on entire neural circuits, not just on this one process. At least, that's how I see it.
The sample size has nothing to do with the distinction between a survey and a study, as far as I know. Either could have a small sample size or a large sample size.
If they got a statistically significant result given some alpha value, then that's a valid result, assuming the experiment itself was set up in a valid way (random sampling, controlled, double blind, etc.). Statistical significance tests take the sample size into account. A large enough difference can make up for a small sample size, and vice versa.
I have said this before in HN, but I'll repeat myself: don't trust this study.
The Valkee company is financially backed by ex-Nokia execs and other people with money and influence in Finland. They have the means to get a small University in Northern Finland to make a study in their favor.
There have been interesting studies about light sensivity in the skin, so why not the brain. However, this study doesn't really prove anything.
Also, don't underestimate the value of placebo in the treatment of mental ailments.
You'd be amazed by how many medical studies uses such small sample sizes.
Often its for a good reason for instance when looking at the effectiveness of a surgical procedure in a sub-group or the treatment for a reasonably rare condition. Sometimes it is because of the need to use a random or carefully selected bias group.
But, as a one-time criminologist's statistician used to samples in 1000s (or 100s at least), I have often concluded that it was just bad science.
and 25 people is a small enough group that you can do just a few surveys, then pick the group that gives the results you wanted, all without spending very much money.
Having light sensitive cells inside your head (in other places than eyes) obviously sounds ridiculous if you believe in intelligent design. However if you think about evolution and how it works, I would say there is pretty good chance all our cells do not have just the functions they absolutely need to have.
It's fairly difficult to pinpoint something that humans have that couldn't have been placed there intelligently. Evolution drives organisms, if at all possible, to co-opt anything that develops because of structural constraints. Most of the time it is possible.
This class of traits is something that Steven J Gould named as evolutionary spandrels. So in practice, I would expect the ultraviolet receptors in the skin to have at least one meaningful function. The fact that exposing people to ultraviolet light changes their hormonal balance would tend to suggest this as well. They're definitely doing something.
As a separate argument, a creationist could also provide some information theoretic arguments for why some cells have pointless features. Unnecessary complexity in a biological organism, like in any other computer program, is a dangerous risk. As risk management, we might want to handle that danger by accepting a harmless redundancy and not building an additional subsystem that chaotically interacts with all our other subsystems.
Skin cells are not part of the nervous system, they apparently use rhodopsin just to regulate melanin. You can make any part of the brain photosensitive by injecting Channelrhodopsin viral vectors, that's an exciting recent experimental area called optogenetics.
Commuters have plenty of artificial light around them. Cyclists and walkers would need this more, but it probably blocks out sound. The whole artificial sun-like light thing does make sense, but mostly as a bedroom light.
This sort of thing just screams bullshit. Yes, I get that light therapy or whatever it's called is prescribed but somehow I doubt that two little LEDs shoved in your ears is anything close to a substitute.
It feels overpriced, but they're competing with daylight lamps, and those are in the 100 - 300 euro range, with most being around 200 euro (I'm currently looking for one, suggestions welcome!). So in that context, they're priced at market-rate.
Has any study been conducted about any possible side effects any such thing would have? after all if light to skull would have been so useful then evolution should have made it so. If it isn't so then either its of not much use or it has some bad effects too.
You misunderstand evolution. The idea is to be good enough to reproduce, not to be optimal. Hence why humans have loads of vestigial crap that serves no purpose.
[+] [-] jot|14 years ago|reply
[+] [-] sambeau|14 years ago|reply
There are a number of holes in your skull and your ears are two of them.
Whether or not the brain reacts to light is either proven or disproven depending on whether you find a flaw in this research or can conduct research that finds against it.
[+] [-] kingmanaz|14 years ago|reply
Light penetrates skin, tendon, and bone, albeit in ever smaller amounts. It is not impossible that the brain reacts to light.
[+] [-] sambeau|14 years ago|reply
Perhaps we should all be taking our earbuds off on sunny days?
[+] [-] sangfroid|14 years ago|reply
If shining light on the brain actually changed the levels of activity, it would have an impact on entire neural circuits, not just on this one process. At least, that's how I see it.
[+] [-] Tichy|14 years ago|reply
[+] [-] pi18n|14 years ago|reply
[+] [-] FaceKicker|14 years ago|reply
If they got a statistically significant result given some alpha value, then that's a valid result, assuming the experiment itself was set up in a valid way (random sampling, controlled, double blind, etc.). Statistical significance tests take the sample size into account. A large enough difference can make up for a small sample size, and vice versa.
[+] [-] exDM69|14 years ago|reply
The Valkee company is financially backed by ex-Nokia execs and other people with money and influence in Finland. They have the means to get a small University in Northern Finland to make a study in their favor.
There have been interesting studies about light sensivity in the skin, so why not the brain. However, this study doesn't really prove anything.
Also, don't underestimate the value of placebo in the treatment of mental ailments.
[+] [-] sambeau|14 years ago|reply
Often its for a good reason for instance when looking at the effectiveness of a surgical procedure in a sub-group or the treatment for a reasonably rare condition. Sometimes it is because of the need to use a random or carefully selected bias group.
But, as a one-time criminologist's statistician used to samples in 1000s (or 100s at least), I have often concluded that it was just bad science.
[+] [-] regandersong|14 years ago|reply
[+] [-] nodata|14 years ago|reply
[+] [-] aes|14 years ago|reply
[+] [-] jpalomaki|14 years ago|reply
Having light sensitive cells inside your head (in other places than eyes) obviously sounds ridiculous if you believe in intelligent design. However if you think about evolution and how it works, I would say there is pretty good chance all our cells do not have just the functions they absolutely need to have.
[+] [-] scarmig|14 years ago|reply
This class of traits is something that Steven J Gould named as evolutionary spandrels. So in practice, I would expect the ultraviolet receptors in the skin to have at least one meaningful function. The fact that exposing people to ultraviolet light changes their hormonal balance would tend to suggest this as well. They're definitely doing something.
As a separate argument, a creationist could also provide some information theoretic arguments for why some cells have pointless features. Unnecessary complexity in a biological organism, like in any other computer program, is a dangerous risk. As risk management, we might want to handle that danger by accepting a harmless redundancy and not building an additional subsystem that chaotically interacts with all our other subsystems.
[+] [-] zerostar07|14 years ago|reply
[+] [-] Tichy|14 years ago|reply
[+] [-] tobylane|14 years ago|reply
[+] [-] mooism2|14 years ago|reply
[+] [-] The_Sponge|14 years ago|reply
[+] [-] kilian|14 years ago|reply
[+] [-] Achshar|14 years ago|reply
[+] [-] Torn|14 years ago|reply
[+] [-] FaceKicker|14 years ago|reply