http://www.sciencedaily.com/releases/2008/01/080124104917.htm

This links to an interesting new study where they are using controlled exposure to infra red light to slow down brain deterioration and even improve cognitive function in certain patients.

So many of us have noticed that our LO's function seems to fluctuate seasonally. Maybe there's something to that.

Torp, forgive my late response.I can relate to the light being a strong factor.Myself, I am more positive when the days are longer and the sun is shining.Can imagine what it does for others