During the fall and winter season, a number of people are experiencing Seasonal Affective Disorder. One of the way it has traditionally been treated is with a dedicated lightbox - a very high intensity light (5k-15k lux) that is positioned somewhere the user can see it.
One of the possible ways such light affect the brain is through being picked up by Melanopsin receptors in the eye and this info being transmitted to the Suprachiasmatic Nucleus (SCN). The SCN makes sleep/wake decisions by suppressing melatonin release.
It has been tested that melanopsin receptors in the human eye respond most strongly to the light at around 470nm wavelength.
My question is about the mechanism by which this light influences the brain - which would have a stronger influence on the brain:
- A constant, high intensity source of light that is ignored by the conscious mind (fades into background)?
- OR An alternating, moving or fading, less intense source of light that the eye is drawn to, such as dancing light, a moving lamp or some other form of light that the conscious mind might be drawn to watch?
To clarify my question, I know that brain has a number of self-attenuating circuits (for example dopaminergic system), where extended release of some hormone numbs the sensitivity to the hormone. I'm interested - are SCN, melanopsin receptors or melatonin suppressing process are also self attenuating, where prolonged exposure to constant light would attenuate these processes?