It doesn't take an expedition to the stars to find ourselves faced with matters that are beyond our understanding.
In fact we don't have to look further than a state of unconsciousness on our own pillows as we lay our heads down for the night.
Among the unplumbed mysteries of the universe, one of the most mysterious remains, what happens when we're asleep? A seemingly related question might be, what's going on in our brains when we're under anesthetic?
Everybody dreams, whether they remember their dreams or not. But somehow the inclination is to think that when we're asleep our minds are turned off. Apparently nothing could be further from the truth.
Researchers discovered that the processes of the brain during sleep are more complex than previously thought.
Researchers from UCLA used mice to study the entorhinal cortex, the part of the brain involved in memory and learning.
The entorhinal cortex was seen to experience persistent activity even during sleep. Interestingly, they learned that it is even active when under anesthetic.
It was previously known that the hippocampus and neocortex are in communication while we're sleeping, performing memory consolidation, which refers to the establishment of our memories.
The neocortex moves into a slow wave pattern most of the time we're asleep, fluctuating between states of activity and inactivity approximately once every second. This neocortical activity is mirrored in the outer area of the entorhinal cortex.
When the neocortex became inactive, the inner entorhinal cortex is persistently active, which is similar to what happens when something is being remembered from the neocortex. This is called spontaneous persistent activity.
Neurons of the hippocampus are then triggered into activity. When the neocortex is active the hippocampus quiets.
Study senior author Mayank R. Mehta is a professor of neurophysics in UCLA's departments of neurology, neurobiology, physics and astronomy. Mehta speculated that all this action is the brain's way of deleting unneeded data of the day, and cleaning up and filing memories.
Mehta worked with Thomas Hahn and Sven Berberich of Heidelberg University in Germany, the Max Planck Institute for Medical Research, James McFarland of Brown University and the UCLA Department of Physics.
Funding for the research came from the Whitehall Foundation, the National Institutes of Health, the National Science Foundation, the W. M. Keck Foundation, the German Ministry of Education and Research and the Max Planck Society.
This research was published on Oct. 7, 2012 in the online journal Nature Neuroscience.
In other research, Max Kelz of the University of Pennsylvania and his team studied an area in the hypothalamus in the brains of mice, after an anesthetic drug isoflurane was administered.
They discovered that use of the drug caused neurons that promote sleep activation. It seemed to indicate that anesthesia makes use of the brain's sleep circuitry to bring on unconsciousness.
This seems to confirm the notion that when we're put under with anesthesia, that we are indeed put to sleep.
The research was reported on Oct. 25, 2012 online in the Cell Press publication Current Biology.
Sources:
Sleeping Brain Behaves as If It's Remembering Something. Sciencedaily.com. Retrieved Nov. 15, 2012.
http://www.sciencedaily.com/releases/2012/10/121007134729.htm
Anesthesia Drugs Really Do Put Us to Sleep. Sciencedaily.com. Retrieved Nov. 15, 2012.
http://www.sciencedaily.com/releases/2012/10/121025122216.htm
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Reviewed November 16, 2012
by MIchele Blacksberg RN