These people think it does not require a brain.

http://www.bendbulletin.com/nation/5...al-that-sleeps

The methodology is interesting and certainly warrants another look.

We need the refresher. If we don't have a brain the question is moot.

We are not jellyfish and never have been.

I'm not clear what you are saying. Are you saying the sleep is only useful if the creature has a brain? That without a brain, sleep is unnecessary?

A low energy mode might be fit.

There may not need to be any other reason than this.

My guess is that it was the low energy mode trait* that led to sleep being common and that all the other uses for sleep were refinements on top of it.

*I'd include in that things like keeping warm and safe. My 'other uses' I'm referring to internal restorative/learning/cleanup type stuff (and also social bonding).

Sleep is great, unless you have insomnia. Does insomnia require a brain?

I don't think its the function of the brain to "put us to sleep' in the manner of a on/off device.

During sleep we are unconscious and in other words non sentient. The human body , in sleep, still has cardiac/respiratory rhythms and a digestive activity.

The sentient activity , thinking, and thought borne activity is no longer evident. With this in mind, that to which is responsible for sentience, is no longer present.

If I say the brain is responsible for sentience then in sleep, with it still present, it would perforce have an activity in which it "turns off' its own activity, ala the radio. this is the logical concatenation of material events if the brain is considered prime ruler.

There is another approach in that the "soul's sentient activity"( that to which we have to proceed cautiously with in this expose) actually "pulls out" from the physical body in sleep . The soul and spirit of man actually leaves the physical and life bodies at sleep and enters into higher realms.

This sentient body , that which the soul utilizes to gain fruits of the earth, then leaves the body and does refurbish its abilities in the world of its origin, the soul world. The earth is not the seat of this body , not being what we may call "physical" but the supersensible body attached to our physical and life bodies known as our "temple" .

When a man arises in the AM one may note the "jolt" of awakening which is this sentient body returning to its temple and we see our surroundings.

When a man dies , he again leaves his temple as in sleep, but his "life body" referenced above leaves with the soul and spirit and we have the "life flashed before my eyes" effect which is pictorial. Therefore the corpse is left at this event and it enters into the mineral kingdom, the ash of man.

This is why its been said that sleep is the "little brother of death".

The above refers to four (4) bodies of the human being and in this the scientific study of Man can only be clarified through human knowledge or comprehension.

So that we can kick a$$ when awake and when it counts (during the day) more than we could have otherwise given the historical daily energy budget. It gives an edge that exploits the night period to park the activities that would have limited benefit if not sleeping.

What exactly can you do that brings food etc at night time? So its best to use it for rest and recovery of all useful processes. I bet it has to do with the day night cycle. What was the day-night cycle 500 mil years ago when the big game got started?

My speculation is that it started as an advantage in economic energy usage terms adjusted to the natural light cycle that was then exploited to add all kinds of other benefits too that by now have made not sleeping impossible due to the value it offers. But that value was created over time forced by the properties of the planet's day night cycle. It might have not been necessary initially before evolution to higher animals took it there for economic reasons.

It's clearly linked to the day-night cycle and the predictor-prey situation. Arguably reptiles slept at night so mammals slept by day.

Sleeping in the afternoon is the nuts. Ruined for many only fairly recently when when we stumbled upon agriculture

Well, I would say sleeping clearly needs a brain or equivalent organ, which might as well be called a brain.

What use? I think there are many reasons for sleep. Although cause and effect might be difficult to untangle.

For instance, sleep is useful for inducing beneficial behavioural patterns on animals. An animal sleeps during the time when it would be dangerous to be active. Or when there is no prey available. But is this a reason for sleep, or evolution adapting to the necessity for sleep?

We're just blobs of cells.

The fact that sleep restores sore muscles, speeds up healing, fights infections, does a bunch of things outside of the brain leads me to think it's probably something at the cell level rather than the organism level, that just got loosely coordinated with behavior. The tail is wagging the dog here. It could even be something developed out of something as low level as single cell resting behavior in low food settings, that got co-opted when multicellular organism arose via signalling.

Your study certainly adds a data point.

This quote though is hilarious:
And shows how truly ignorant we are yet about this complex machine.

Interesting thought Masque. Do you think we wouldnt need sleep if we would have evolved in a world where the sun always shines?

So what do you think about the study mentioned in the OP?

I think the word sleep is being strained.

Life forms change state depending on environmental stimuli. For instance, plants can change depending on sunlight direction and availability. I am sure with enough imagination you could refer to this as sleeping, but really this would be a misuse of the word.

Jellyfish do have a nervous system, however, they do not have a central control area that could be labelled a brain. I can easily imagine that this nervous system could have different states that vary depending on timing and outside stimuli, in fact, this is what the paper claims.

So in effective control of the Jellyfish is distributed over the whole nervous system rather than collected in a central area. I guess you could say that the Jellyfish's whole nervous system acts like a brain as it has a meta state-based structure. Think of a computer made out of bits of string, matchboxes and sticky tape!

The jellyfish doesn't have a central net of neurons, per se, but does have a neural net throughout the body, thereby having a nervous system.

If a human being is considered then the spinal cord, in evolution, can be considered a precursor of the brain, which is the evolutionary estoppel of the spinal cord.

The spinal cord is associated with the internal milieu of Man who, in an evolutionary sense, progressed to the brain, the last act of the spinal cord. This brain, with its 12 cranial nerves then became the system to which the external world became perceptive whereas in the past, man at some time was majorly perceptive or living within his internal activities.

The animal, and I would picture all animals, have their spinal cord parallel with the circumference of the earth . Whereas Man, in an evolutionary step, brought his spinal cord perpendicular to the earth and of course associated with this is the brain, or central nervous system .

This can be seen in an infant who at some time in his progression stands upright and this is also the beginnings of man's sense of his "I" or "Ego" as he progresses to a thinking and thought activity to which the animal is not capable. Man is ensconced within the cosmos differently than an animal .

From the study, or your copy, it is noted that the jellyfish appears to be sleep deprived and does display "suffering" , which of course is true. this in some manner is bringing ideas and concepts to the wrong place as the brain is seen as not only a thinking activity but the origin of "will forces" and also one's "feelings".

What can come of this study is that the jellyfish can "suffer" without having a central nervous system of if the idea is carried cross species then the central nervous system is not the source of "feelings" or "suffering". Of course the neural net is still there which can can bring counterpoints to this idea.

In Man, who is tripartite, there is the nature of thinking/cognition, feeling and willing.

By really going material or physical here, it can be said that thinking cognition is accomplished within the nervous system, not only the brain.

"Will" activity is associated with the metabolism/extremities as obviously we walk the earth, a will laden activity.

"Feelings" is associated with the central activity or the confluence of the circulatory and respiratory rhythms. If one disrupts these rhythms we can experience untoward feelings and likewise if the rhythms are in order there appears a feeling of well being. "Feelings' are within our chest cavity.

Please note that there are nerves not only in the head but in the chest and limbs/digestion and vice versa and so there can be feelings in the head and also a will laden activity associated , for one, a train of thought.

The idea is not to display how man is "animal like" but to clarify the differences .

Don't read about this if you ever want to sleep again:

Fatal Familial Insomnia

What is that, "the ring" equivalent terror movie for sleep?

Dancing cat didn't click dot jif