Scientists wanted to find out if there was a special group of cells in our eyes, apart from the known rods and cones, that clued us in if we were already under the spell of night or day. And as it happens, human eyes and mouse eyes are quite similar in the way they work. So they tested blind mice. I can imagine the jokes in the lab when they were conducting this experiment. You are probably wondering how the scientists were able to recruit the blind mice (clue: what are the odds that they had a sign in Braille published announcing a call for volunteers for blind mice?) or more importantly, if there were exactly three blind mice to complete the joke.
We have long known that our eyes consist of photoreceptors called rods and cones, which are responsible for detecting changes in light (dimness or brightness) and colors. Three years ago, David Bersen, professor of Neuroscience at Brown University, and his colleagues discovered a third group of cells in our eyes that adjusts for the overall brightness, as opposed to changes in light detected. A study published in the journal Neuron in January 2006, illuminates the path through which this special group of photoreceptors is able to guide our internal body clocks or circadian rhythm.
This third group of photoreceptors is certainly different. For starters, unlike "rods" or "cones," monosyllabic labels that are easy to remember, this special class of circadian detectives has a name that has 17 syllables. Called intrinsically photosensitive retinal ganglion cells, or ipRGCs, I really think it could not have hurt to assign a nickname to it, maybe by way of tribute to the mice – "Mickey cells" or "Minnie cells" if you want to be more gender-sensitive. Another difference is that unlike rods and cones, which would have to negotiate with about two to three levels of other cells that act like "middlemen" before the messages get to the brain, the ipRGCs have a direct link to the brain.
This is important because it implies that when a person has been diagnosed as "blind" because her eye’s rods and codes are irreparably damaged, this does not necessarily mean that all of her eye’s functions are deleted. Also, this finding could also help us better understand how the eye influences the inner sundial that influences our bodily functions, especially in cases of jetlag or even in graveyard shifts.
Not only could the blind "see" day and night, a more recent study even found that those of us who are not blind could still be helped with an extra serving of light every day. According to the recent Aug. 22 issue of Current Biology, Gilles Vandewalle of the University of Liege, Belgium, and his colleagues wanted to see if exposure to extra bright light during the day could give an extra boost to one’s alertness. This is new since the more obvious and more studied effect of bright light has been on subjects exposed to darkness. It is no longer a secret that exposure to bright light at night influences the internal clocks in our bodies, our heart rate and even the hormones we release. The studies found that subjects who were given an extra boost of light in the morning, aside from ambient light, were significantly more alert. But I wonder how would this explain, at least in part, why shops that are more lit report significantly higher sales? Does more light make us buy more? Why? The new studies are interesting because they give basis to what I think will be an additional mainstay item on the service menu of all spas – "light therapy" even in sunshine-rich countries like ours, particularly to clients who are always tired and therefore, less alert. Needless to say, the extra light was not a flash of light that was beamed directly to the retinas of the subjects. They were just the equivalent of letting more light into the room by adjusting the drapes or the Venetian blinds so do not have any ideas about a spectacular light show for your spa as part of your "light therapy."
If a little bit of sunshine could help us be more alert, what could increasing levels of dimness imply? I have an unproven standing theory that a lot of relationships that were concocted in noisy bar rooms in the age of disco, did not endure because they really could not hear what each other had to say in those places and were all in for a surprise when more decisions after the wedding had to be made under daylight scrutiny. This light-and-alertness experiment behooves me to expand my theory. Will the characteristic dim ambience explain the "dim"-witted decisions we make by candlelight in discos, restaurants or in bedrooms?
How about those places deprived of electricity? Do those who cannot afford electricity more often live and make "dim" decisions in the dark? If this were so, whew, perhaps we have just found a way to curb population growth by literally just installing nightlights (like lampposts that automatically turn on only when it gets dark and off only when daylight arises) in every Filipino home so as to make them ever so aware and therefore alert of the consequences even of their most private actions, especially if they could not be responsible for them. Surely, the sectors who are against what they claim are the "unnatural" choices for population control have nothing against more light or sarcasm as a way of comment or contribution to solving the national population explosion. I am sure those sectors would not mind footing the electric bill for the national interest.
I wonder if we would also make better public decisions if we added more light into our working spaces. Maybe we can have a lobby to open the curtains in those important government offices so we can nudge this and that government official to think more clearly. We could rally in the streets and make for an interesting demand. But I don’t think we can count on it because chances are, they would miss it because the drapes of their windows and their minds would be drawn.