World News - Fight winter depressions with Bluelight mobile

It has long been recognised that light affects people's mood and ability to work, whereas light deprivation leads to feelings of exhaustion and fatigue. All psychological, physiological and biological functions are controlled by a biological clock, which in turn is regulated by exposure to daylight.

It has recently been discovered that special receptors in the retina of the eye respond exclusively to blue light and transmit electrical impulses via nerve fibres to the circadian clock in the suprachiasmatic nuclei of the hypothalamus in the diencephalon. This stimulates the secretion of various brain messengers. The hypothalamus is connected to the hypophysis, or pituitary gland. These two parts of the brain regulate the production and release of hormones which act upon the epiphysis, or endocrine gland, which in turn produces hormones, including, in particular, melatonin ("the sleep hormone"). The nightly secretion of this neurohormone into the bloodstream takes place in a 24-hour cycle (the circadian rhythm). It leads to fatigue and the need to sleep and/or to a mood of depression.