There have been some interesting studies done at UCLA that may be hold some good for people who suffer from Narcolepsy and a sleepiness associated with Parkinson's and it might also mean some good news for anyone who suffers from seasonal depression! Researchers at the university have identified the group of neurons that mediates whether we respond to light by becoming stimulated-- or not.
So the long and short of the study is that in the hypothalmus (an area at the base of the brain and is responsible for control of the autonomic nervous system, body temperature, hunger thirst, fatigue, sleep) there are cells that release a neurotransmitter called hypocretin. In a study with mice, those with hypocretin showed an intense activation of the cells (but not in the dark!) while those without it were unable to stay awake even in bright light. And it is this loss of hypocretin that causes chronic sleep disorders. So, by introducing hypocretin (or boosting it) they will be able to increase the light-induced arousal response while blocking them will induce sleep. Jerome Siegel, a professor of psychiatry at the Semel Institute for Neuroscience and Human Behavior at the university noted, "The administration of hypocretin may also have antidepressant properties, and blocking it may increase tendencies toward depression. So we feel this work has implications for treating sleep disorders as well as depression." Since seasonal depression is connected to light stimulation, it seems likely that these results could have some very positive results for those of us who get the winter blues!*
Could be blue skies ahead for those who suffer depression!!!
*See the whole article at Science Daily. Brain Cells Responsible for Keeping us Awake Identified.