the suprachiasmatic nucleus (SCN)
receives information about day light and
day length from the eyes, where such
information has been processed by the
visual area in the occipital lobe and
relayed to the SCN via the optic chiasm
(from one hemisphere to the other), the
SCN then processes this information and
triggers different rates of release of
melatonin from the pineal gland. Increased melatonin release triggers decreased serotonin production, creating feelings of sleepiness during the night time, where there is little exposure to light, conversely, during the daytime, when there is high exposure to light, the SCN triggers the pineal gland to release less melatonin over a longer period of time, resulting in increased serotonin
production, creating feelings of wakefulness
