gyuri at usa.net
Sat Sep 16 02:19:38 EST 2000
In article <8puas1$1pt$1 at nnrp1.deja.com>,
teyh at my-deja.com wrote:
> Hi all,
> Thanks for the excellent discussion! I haven't read such good
> spirited discussion on internet for quite some time.
> Since one can not keep taking without giving back, I will chip
> in my two cents:
> I believe the basic function of sleep is to stop the
> fully-awake cycle and start a maintenance cycle. The Hypothalamus
> determines when sleep is needed:
> (a) To refresh the body: human body generates many waste and
> some of them are poisonous if not clean up in timely fashion.
> Hypothalamus monitors the contents of blood and orders
> a maintenance cycle should body is in bad shape. This is
> when a sick patient starts to feel sleepy.
> (b) To refresh the brain: as a special case to (a), the brain
> is often the first components of the body that signals the
> need for a maintenance cycle. The brain consumes the majority
> of energy and blood supply in normal condition. A high school
> student often feels sleepy due to heavy homework.
> (c) To refresh the memory: as a special case to (b), the memory
> encoding/retrieval is heavy part of the overall consciousness
> process in brain. The cortex that dominates the memory and
> thinking process is the prefrontal lobe, it consumes most of
> the blood supply and energy of the brain. Thus it is often the
> first components in the brain that triggers the signal for a
> maintenance cycle.
> The maintenance cycle is signified by a 7-13 Hz alpha wave.
> It may not actively clean up the neuron, but it does help
> inhibit the neuron and send them back to initial state.
> (d) To calm the emotion: as another special case to (b), the
> emotion system (limbic) is also part of the consciousness.
> The limbic system causes emergency reaction and results in
> consuming large amount of blood supply and energy. The
> consequence is also signals for the need of maintenance
> cycle after the emotional reaction.
> However trying to sleep after an emotional event is very hard
> since many neurons are fired up to the fullest and is
> extremely hard to tame them with the alpha wave. Sleeping pill
> is often needed in these cases.
> (e) To preserve energy: Even if none of the above occurs, the
> hypothalamus has an internal biological clock to mandate
> the 'wake' and 'sleep' cycle. It is normally coincide with
> the 'day' and 'night' cycle to preserve energy when there is
> nothing to do.
> In modern society this biological clock is often disturbed by
> the artificial light. Many young people stay up all night
> dancing until cases a-d arises.
> We still have a lot to learn in this subject. Again, thanks
> for the excellent dialog!
I also thank you for your valuable contribution to the subject and I
cannot argue the validity of your statements.
Being a computer scientist, my current approach is more information
oriented that is relevant to AI machines, in particular ANN (Artificial
Neural Network) machines.
With no doubt, energy conservation is certainly an extreamly important
contribution to sleeping but may not be the main cause. There may be
other important reasons which relate to intelligence itself and might
play a very significant, if not even a more important role to sleeping.
The brain's job is to serve as the central nervious system to the
biological body and provide intelligent control of that body.
When a person is awake, the brain is always active. It commands
constant activity during the day.
No normal person could sit in a couch, stare at the wall and think
nothing for hours. The brain's job is to be constantly active when
awake. It's constant activity continuously keeps on sparking us to seek
sources of information to feed the brain continuously, so it can
perform its processing duty against those inputs and make decisions
If the brain would not have access to information, it would go insane.
This is because when the brain is used, neural networks are constantly
evolving. If established neural connections are not sparked for usage,
the connections begin them weaken.
That is the ingredient feature necessary for constant adaptability to
changing environments. Neural networks must constantly form and change.
Our ancestors had nothing to do at night, it was better not to make any
noise to avoid being noticed by predators, so to avoid neural
structural deformation, the brain might have gone into a neural
structural conservation mode, or sleeping.
This view I presented here about the importance of sleep when the
source of all or most of sensory inputs are cut off, becomes a very
important feature when designing a constantly working ANN system based
on the structure of constantly evolving neural networks.
ANN systems resembling neural networks of our brain would receive
constant inputs as well in the form of internal thought processes, even
if external thought processes are not present at a given time. However
due to the nature of neurons, any neuron that is not used will deevolve
from its network. That includes neurons and neuron groups evolved to
serve connections to sensory inputs.
If we want the ANN system to be adaptable, we cannot allow it to
perform endless thought processes if no sensory inputs are arriving
from the outside world.
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