The Physics of Sleep

Scott Aaronson tries to explain why beds exist. One can read:

This suggests an answer to a question raised by a colleague: is the purpose of a bed to approximate, as well as possible on the earth’s surface, the experience of sleeping in zero gravity? Unless I’m mistaken, the answer is no. Sleeping in space would be like sleeping on a bed that was too soft, with the same potential for back problems and so forth.

Let me be very clear, zero-gravity is no panacea. In space, people tend to get sick for other reasons than sea sickness (astronauts do barf in zero-gravity aircrafts where sea sickness is an issue). Some people suggest that space sickness which generally takes a day or two to get accustomed to, is related to the extension of the spine. However, having experienced zero-g with closed eyes, I can attest that it puts  the experience right into one of those never ending fall scenario that makes up many nightmares. The astronauts I talked to told me that they never took long periods of sleep. In order to do so, they also have to be strapped into place so they have to feel something while sleeping (touching something seems important). One wonders if the short sleeping periods in space is the result of the excitement  of being on a space mission or some more physiologically based mechanism at play. Recall that most people lose a large percentage of their bone mass in orbit and that there is a similar bone loss issue with people lying horizontally. Elderly folks for whom sleep is also an issue also have a bone depletion issue as well. In summary I would not be surprised if the amount and strength of the contact experienced by the body (that covers the issue of hard and soft beds) is directly related to something more physiological. We already know that some cells respond to gravity.

On a different note, when we flew a star tracker on Columbia, I got to be speak with the PI of an experiment on bone loss in space who was on our flight. He had tried for many years to get many different parties involved in that lengthy process of designing a conclusive space experiment  focused on understanding the problem of bone loss in space. The loss of the Orbiter was sad on so many different levels.

Is your desk a reflection of your memorization process ?

It's funny, it looks like one of the ways I am staying on top of several subjects that are not part of my day-to-day job resemble some of the techniques Jessica Logan describes as potentially interesting for memorization. She just gave a seminar at Rice on "Brain and Behavior: How We Create and Maintain Memory in Early Adulthood and Advanced Age" (webcast is here)

Brain and Behavior: How We Create and Maintain Memory in Early Adulthood and Advanced Age” - No one likes it, but it happens to the best of us—that frustrating feeling of trying to remember something you know that you knew at one time, but which now inexplicably eludes you. From older adults lamenting another "senior moment" to students stumped on a final exam, memory failures are an unwelcome but woefully familiar experience for everyone. This talk will focus on research that strives to help us understand how some of these failures occur and how we can improve our chances of avoiding them in the future. Cognitive research that integrates both behavioral and neuroimaging (fMRI) techniques to explore memory formation and retrieval in healthy younger and older adults will be discussed.

In her fascinating presentation, she makes the point that studies seem to show that cramming for a subject area is worse in the long run with regards to remembering it. She also present results for two other techniques called equal and spaced interval technique. In cramming, the memorization happens by repeating over and over the same subject area and then take a test on it. Most college students know that the technique might work for a test but that they are not optimal strategies for the long term. The two other techniques are using some type of time interval between repeating the same subject area in order to reinforce memorization. The equal time interval asks for an equal amount of time between recalls whereas the spaced interval techniques demands that recall occur at different (random) time intervals. Interestingly, young adult fare badly in recalling memory acquired through the spaced and timed intervals whereas old adults do see a benefit to these methods (as opposed to cramming). Additional information can be found in this paper [1]. I find it fascinating because the way this blog is structured and how I set up my desk remind me on how I eventually always randomly come back to a subject, rediscover it and remind myself very quickly of the important lessons from it. The market for product on memory is very large, yet none of these techniques seem to be proposed. I note her statement about spaced memorization:

• Making practice more difficult initially can produce better performance on a final test
• Challenging the learner in between practice attempts enhances the benefit of repetition

I think this is the main reason why people should read this blog on compressed sensing when trying to learn something else. The issue of sleep is also mentioned indirectly in her 24 hours study and I wonder if they yield the same results as for the sensorimotor control.

Reference: [1] Does Expanded Retrieval Produce Benefits Over Equal-Interval Spacing? David Balota, Janet Duchek, Susan Sergent-Marshall, and Henry Roediger III, Department of Psychology, Washington University.
Photo credit: ESA/NASA/ASI/JPL/SSI, Radar view of Titan's methane lakes.

Hard Problems: Walking Dinosaurs wearing make-ups while sleeping.

I am always a little astonished by some things that I do not see implemented because they are too hard. Yet, I don't even see them being even attempted in the first place even though there is a very large market for each of those. Here they are:

• How come we don't have Jurassic Park with walking dinosaurs ? everytime there is an animotronics coming in town, you have lines of kids waiting to see those things even if the time spent waiting will be longer than the time spent watching them and yet we still don't have walking dinosaurs (except when a human is inside). How come ? (my interest here lie in muscle, autonomous ). It looks as though we have only been able to devise their gait recently. Some people are already making a business case that building them will get people to come.
  
• Knowing that some women spent as much as two hours every day to do their make-ups, how come there is not a Make-up robot for women ? ( autonomous ). This is all the more interesting that much technology goes into changing the face/shape of women in magazines. How come there isn't a similar technology to evaluate if the make-up is good enough ? Think Snow White mirror.
• People spend an average of 8 hours sleeping yet there is no real good technology to improve sleep. How come there isn't an autonomous pillow that shapes itself around one's head over the course of the sleep. Or since a 32 GB SD card can allow people to record entire sleeping patterns for over 8 hour. What is the software that will allow to check if the pattern is a good one or a detrimental one ?
  

We sleep because we want to assimilate bimodal priors

Pierre sent me a pointer to a Time article on why we sleep where they seem to talk about the latest research showing that it is not because of your body but rather your brain that you sleep.

In the PBS/Nova story on the secret life of the Brain, they report on experiments done on rats and one experiment where people were reading letters:

Other experiments supplied more direct evidence that sleep is crucial for learning. Human subjects were trained to identify letters that appeared for a blink of an eye on a computer screen. Then, half of the subjects were sent home to sleep, while the other half were deprived of sleep for the entire night, and only then went home to rest. Two days later when all the subjects were already rested and refreshed, the scientists checked their ability to read the flashing letters. None of the participants were tired, and yet the people who went to sleep right after the training performed much better than the ones who went to sleep a day later. This suggests that the night sleep immediately after the activity was crucial for gaining the most from the training session. Without it, the training was much less effective.

More importantly, in this study on learning and reducing behavior to some Bayesian process, the experiment reveals that sleep actual helps remember Bayesian unimodal and bimodal priors. An interesting question I have about this study is: at what point people become experts, when they have learned bimodal priors, tri-modal priors ? is the time needed to learn a multi-modal prior (say n), an O(n^p) process where p > 1 ? Does sleep help reduce the complexity from a high p to a low p ?

While we are it, it looks like that a shift from sleeping late to rising early may signal end of adolescence, many people I know in their forties, are still teen-agers...

We don't care about sleeping like babies no more. Part deux.

In a previous entry, I mentionned how bad it would be to build a business around better sleeping facilities since most people were willing to go the chemical route anyway. This article from Forbes (thanks Cable), shows that it will become actually worse that than:

For the first time, the U.S. Food and Drug Administration has approved a sleeping pill without restrictions warning doctors not to prescribe the medicine for long-term use. Lunesta, formerly referred to as Estorra, will be available in pharmacies in January. It will be marketed with a $60 million direct-to-consumer advertising campaign.

A $60 million ad campaign, uh ? What are the chances the average doctor will resist the pressure of his customers to prescribe the medicine for long-term use ? My take is: very few will. Don't worry though, if you have any apnea and your heart stops beating, you just need to have one of these defibrillators from amazon.com next to your bed and expect somebody to use it properly.

We don't care about sleeping like babies no more

In a previous entry, I was making a mention of an italian study on sleep. This new study from SleepApneaInfo.com shows that Americans downplay sleep as crucial to health

Although they admit that a lack of sleep affects their work and sex lives, the majority of Americans don't believe that sleep is an important factor in maintaining good health, a new poll finds.

The survey of 2,442 Americans, conducted by SleepApneaInfo.Com., which is run by companies that make sleep disorder therapies, said that 62 percent of Americans thought that diet and exercise were more important than sleep in staying healthy and happy. Seven percent said none of the three was important.

According to the survey results, 58 percent of employed American experienced some daytime sleepiness, while 39 percent said that they don't have sex because they're too tired.

About 40 million Americans suffer from sleep disorders, and 18 million of them have obstructive sleep apnea, in which the person stops sleeping many times a night because of a blocked airway.

With this type of results, one wonders how the sleeping industry could awake...

Is this our future ?

I Know I talk a lot about the sleeping industry, but I think taking a nap is not a really good solution. What about sleeping better during the night ? wow what a concept.

That's what I am talking about.

This company has sensors that record data without touching the body: Nexsense wants a bite of the sleeping market. Please note that they do not say anything on HOW they get their measurements, vaporware anybody ?

Dream Catcher

This new gadget is very appealing but two things come to my mind:
- why would you want to direct your dream rather than simply remembering them,
- here is a product that sells for 136 buckarus yet has only proven to be effective in 20 percent of the time.
In other news, the use of oxygen mask during sleep for those with sleep apnea is effective in reducing heart problem down the roads according to this finding. The point of that last article is that there is a need for such study so that people overcome the perceived annoyance of having a mask while sleeping: It can save your own life, the study says. What about devising a better way of doing CPAP instead on relying on fear ? (Thanks Cable for the link).

Why the sleeping industry cannot wake up.

In this study of sleep patterns of adolescents in Italy, one can evaluate one of the reason there are not that many customers for a solution to sleeping problems. Out of about 20 percent of the population that self classify itself as poor sleeper, only 2 percent will try to do something about it. In most cases, they will resort to chemical means. wow...

The sleeping industry awakes

It looks to me that the idea of having a sleeping industry is long overdue: Here is room designed that puts customers to sleep. Not only that but "With sleep disorders a rising concern in Japan, the company is betting the elaborate system, which includes a special bed, wide- screen TV and sound-absorbent walls, will cater to a growing market. " The question is, am I too late ?

Sleeping like a baby

I wonder when the "sleeping" industry will come up with something similar to this Adidas shoe.

Better Sleeping Technology IV

Here is another reason as to why you should have a good night sleep (A new study offers new clue to good memory.) While it is interesting to have college students trying to remember different items after a good night sleep, it probably also negate the fact that most older people ( I mean older than college students), while sleeping as long as they want, have sleep patterns of lesser quality. Somebody recently asked me what technology could also be included in this "Better sleeping technology program". Well for one, it seems pretty obvious that some of this technology include acoustic devices evaluating the resonnance of one's room, mechanisms for storing and dating noises made during the sleep, light collecting devices for evaluating its influence on waking mechanisms, cameras evaluating the flora in your mattresses (are you allergic to them, do you sneeze because of them and wake up because of it ?), cameras evaluating your movements over night, sensors evaluating temperature and humidity. Evidently, all this information would have to be recorded on a noiseless computer.

Better sleeping technology III

Just as I was talking about it, here is another study (some more details here)performed on college students on the need for a period to "sleep on it." We all knew it affected learning for the young and the health of the old. I did not realize my brain was shrinking as a result of jet-lag/sleeping pattern disturbances though. On a related note, the process of memorization is intriguing. I have observed that most people flying on the kc-135 did not remember much of their experience. This is why the french caravelle and the Weightless Wonder IV and V had LED parabola counts in them: People in the plane would not realize how many more parabolas were left. Most people flying in these birds generally do not realize they are flying 2 to 3 hours. The short term memory is deeply affected. So one has to wonder how weird it must be for astronauts to sleep. In most cases, they don't as they are too excited. Maybe some technology other than cheaper mattresses will come out of NASA's investigation of their astronauts sleep patterns especially in light of the new Moon-Mars initiative. Anyway, if anyone could point me to it, I am trying to find this study that showed that a good night sleep or a rather "boring" time between being exposed to facts and trasnfering them in the long term memory part of the brain was found to be about 6 hours....

We also need cheaper sleeping technology

Cable just reminded me that most people see only one thing when buying mattress and this is the price. I have to agree 120% since I still cannot fathom why it takes me a $100 to buy the most rudementary mattress. However, the sleeping technology I was mentionning is not just the mattress per se. It also includes some electronics and recording capabilities for diagnostics purposes. We are talking about much more advanced than a confortable pillow. So, in line with how disruptive technologies end up being large markets, one has to think of specific niche where one can grow the market. Affluent people, such as customers of the sharper image, could be part of that constituency but I think one should be able to find a much broader one. I have to think about it.

We need better sleeping technology

No matter how much I search, I am always amazed at the lack of intelligent solutions for sleeping better. Sure, you can always pay for a better mattress, even buy one of these NASA mattresses. But why does one need a visit to the doctor and then to the sleep clinic to figure out that you are snoring too loudly, have sleep apnea, grind your teeth, sleep walk, talk aloud, never reach deep sleep....This is all the more important that since a bad sleeping experience is at the root of many health problems or early symptoms of diseases. The surprising part is really that since sleeping is about 1/3 rd of our lives one would expect an overwhelming amount of services or products to make this a more pleasurable experience. Eating for instance, takes only a fraction of time in our lives compared to sleeping. Yet, there is an entire industry devoted to it, a multi-billion dollars one at that. Just imagine now, companies dedicated to sleeping better...

Waking up

All of us at some point in time have had problems waking up in the morning. Lack of sleep, will or whatever, I have always been astonished by the lack of offerings in terms of intelligent waking mechanisms. I mean, a simple buzzer just doesn't do it. There are very few alarm clocks with two settings and I know of no alarm clocks with an intelligent way of waking people up. One could think of building an alarm clock that fits ones sleeping patterns and waking patterns. Some type of algorithm using a bayesian approach may be the answer.