A Sleep Study

So the way in which the suprachiasmatic nucleus (SCN, an area within the brain) has been thought to regulate our circadian rhythms may have just been overturned.  Circadian rhythms are the daily rhythms of our bodies (from the Latin circa = about or around and dia = a day), most commonly associated with sleep and waking cycles, though there are other things that fall into daily rhythms (like levels of circulating testosterone appear to be highest in the early morning).  For a while now, it has been suspected that the SCN regulates our daily rhythms by having the neurons within the SCN fire really fast during the day, and then fire more slowly at night.  A new study in the journal Science suggests, that if you look just at the neurons that are most likely the "clock" cells, they aren't firing all day, just in the morning and in the evening. Of course, this isn't really overturning any widely held myth about neuroscience, just adding to the story.  The SCN is still likely the master clock within our brain, and many of the downstream effects of its circadian regulation (like the secretion of melatonin from the pineal gland) are still valid effectors of sleep wake patterns and the other physiological correlates of circadian rhythms.  Here's the press release at Science Daily.