[Tyler]

How the brain controls sleep
13 October 2015, 12:00 am

                    Sleep is usually considered an all-or-nothing state: The brain is either entirely awake or entirely asleep. However, MIT neuroscientists have discovered a brain circuit that can trigger small regions of the brain to fall asleep or become less alert, while the rest of the brain remains awake.

MIT NewsLink

Source: AI in the News

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[Korrelan]

I don’t think there is any difference between being asleep or awake except that the brain has less sensory input. 

A good analogy would be a modern car engine; it revs higher the more work it has to do. If your car is idling and you turn the lights on the engine management system will slightly increase the tick over to compensate for the extra current draw. It’s a dynamic system that relies on feedback from both its own senses and the driver.  If you listen closely you will even hear the revs cycle through different frequencies over a period of time, this is not by design… it’s an inherent property of a complex system.  The management might sense the battery is getting low, a breeze mightn't blow into the air intake altering the fuel mix, the car management adapts in real time to feedback and the revs change. The engine is a self contained system that adapts to sensory input.

The ‘states’ of sleep are merely our brains ticking over, not stimulated by sensory input. As soon as a sensory stream (audio: loud noise) is fed into the cortex it springs into action (like touching the accelerator/ gas pedal).  There is a gradient from being sound asleep to wide awake.

Like an engine our brains are a self regulating system that acts on sensory input.  When we look at a scene, the sensory stream from our eyes combines/ adds to the visual feedback stream from our imagination/ memory.  Our internal simulation of the world (as far as vision goes) is updated by both these inputs together.  There are thousands of different feedback networks running covering all our senses, etc vision is only one.

When we rest and close our eyes, the brain settles and its revs drop… but the visual sensory stream from our imagination is still present/ running… and we dream. 

Any thoughts?