|MadSci Network: Neuroscience|
I am not sure what you mean by mindset in your question but if you mean ability to concentrate it is certainly true that we go through cycles in which we are sleepier and at other times we are more alert. Some people are clearly "morning people" and are able to get their best work done in the morning while others are able to do work at night. If you are thinking about mood, this is also dependent to some extent on time of day but more so on how much sleep we have gotten. Circadian clocks control many rhythms in your body and are primarily by the day:night cycle. These "clocks" cause a reduction in cortisol production and temperature and an increase in production of growth hormone and melatonin during the night hours (from fellow madscientist Sue Semple-Rowland, Ph.D.) Melatonin has been shown to be somewhat useful in improving mood in Alzheimer's patients who were depressed and had sleep problems (Journal of Pineal research 1998,25pp177-183). Also steroids (such as cortisol) are well known to affect mood and either cause depression or even psychosis in large amounts. Thus since our bodies do follow a circadian clock and different neuroactive hormones are released at different amounts during the day, it is likely that our brain activity and moods do cycle throughout the day. hope this helps cheers, gabriel vargas md/phd
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