We’ve all seen it happen, marveled at the constancy, and even blamed the friends around us for our own personal breathing. Does this sound strange? I am talking of course about contagious yawning; this is the phenomenon that seeing someone yawn will cause you to immediately do the same. But why, and for that matter, why even yawn in the first place?

More and more researchers seem to agree that we yawn (actually all vertebrates yawn) as a means of brain thermoregulation. This seems somewhat fantastical at first, but let’s look at the evidence. We have associated yawning for years with being tired. Many of us wake up each morning, yawn and stretch as we get out of bed; we are still tired, right? Or better yet, you’re sitting in the back of your 90 minute lecture, and although you’ve been trying to be more attentive this semester, you can’t help but sit, idly yawning and wishing you were back in your bed for a nap. This theory of thermoregulation actually fits perfectly with us yawning when we are tired.

Thermoregulation has long been attributed to sleep. Sleep is believed to allow our body to properly regulate its temperature, so it should come as no surprise that we yawn—or cool our brains—when we are tired. Without sleep, our bodies have difficulties regulating their temperatures; meaning as we get more tired, our brains could be getting hotter. This simple mechanism of yawning would then allow our bodies to compensate for thermoregulatory failure caused by a lack of sleep.

Further evidence would even allow us to predict the frequency of contagious yawning based upon the ambient temperature. Researchers have found that individuals were more likely to yawn in cooler temperatures (below body temperature) than warmer (above body) temperatures. The longer they were exposed to this ambient temperature, the more they followed this tendency of yawning at the lower temperatures. If you don’t believe this, test it yourself. The next time you are outside in the summer (or in a hot room for a prolonged period of time) think about how many times you yawn and then do the same in colder temperatures. The frequency should be significantly lower in the warm, summer weather, especially the longer you are exposed to it, than in the cold winter.

So if we agree that yawning is the brain’s way of cooling down, why then do we need to yawn contagiously? Is our brain just allowing us to remind others to stay cool? This is doubtful, and researchers cannot actually completely answer this question yet. However, some evidence suggests that contagious yawning serves a function of self-processing and is a part of a neural network that is also involved in empathy.

So the next time you yawn (and I’m sure you did a few times while reading this) simply remember that your brain just needs a quick flux of air to cool off, so it can continue to perform the millions of incredible tasks you make it do every minute of every day.

Really? The Claim: Yawning Cools the Brain – NY Times

Contagious Yawning and Seasonal Climate Variation – Frontiers in Evolutionary Neuroscience

Yawning and Stretching Predict Brain Temperature Changes in Rats: Support for the Thermoregulatory Hypothesis – Frontiers in Evolutionary Neuroscience

Thermoregulation and Sleep – Annals of the New York Academy of Sciences

http://onlinelibrary.wiley.com/doi/10.1002/cphy.cp040259/full

Sleep, Thermoregulation, and Circadian Rhythms – Comprehensive Physiology

Let's hope he doesn't show up in your dreams.

Since dreaming occurs while sleeping, it is no surprise that the sleep cycle, during which the brain experiences patterns of varying electrical activity, has been implicated in dream theories. Each cycle consists of five stages – two stages of light sleep, followed by two stages of deep sleep, and completed with a stage of rapid eye movement sleep (REM). Unfortunately, there is no representative electrical pattern associated with dreaming, but REM and non-REM sleep have both been connected to the brain’s analysis of waking experiences. Pierre Maquet at the University of Liege, Belgium, observed deep non-REM sleep and found that the brain’s electrical activity mimicked the electrical activity elicited during waking experiences.

Not only do we replay events in our dreams, but we also seem to process, integrate, and store the information for future use. Robert Stickgold of Harvard University found that those who had non-REM dreams about a task that they were asked to complete, proceeded to do better on it. Stickgold proposes that “non-REM dreaming might be more important for stabilizing and strengthening memories, while REM dreaming reorganizes the way a memory is stored in the brain, allowing you to compare and integrate a new experience with older ones”. On a different, albeit related note, daydreaming activates a part of the brain called the default network. This region has previously been shown to be associated with memory processing. Be sure to mention this to your professor next time you’re caught not paying attention in class.

Matt Walker of the University of California acknowledges that dreaming has an important role in memory, but argues that the main function is emotional homeostasis. Walker has found that REM sleep facilitates the strengthening of negative memories. He believes that experiencing the negative emotion in a dream state can diminish the intensity of the emotion, making it easier to deal with. In those with post-traumatic stress disorder, however, this process seems to fail. Boston University’s Patrick McNamara agrees with Walkers’ speculation. He believes that “non-REM dreams help us practice friendly encounters, while REM dreams help us to rehearse threats”.

While dreaming, the brain rewires itself and forms new connections. It seems that this curious kind of consciousness does not reveal our secret desires or open windows into our hidden selves, but instead plays an integral role in making us who we are. Sorry, Siggy.

To view the original article from New Scientist, click here!

Maciek Drejak Labs released an app earlier this year for the iPhone (which can also be used on the iPod Touch) called “Sleep Cycle.” Recently, Lifehacker rated this App the best alarm clock application function for smart phones for its weekly Hive Five feature.

The way this application works is by monitoring your body movements during sleep. The user is instructed to place the phone face side down between the fitted sheet and the mattress. Over the course of the night, the program registers high amounts activity (movement) as “awake,” moderate activity as “Dreaming” (REM sleep), and little to no activity as “Deep Sleep” (slow wave sleep). For the first two or three nights of use, Sleep Cycle familiarizes itself with the user’s movement patterns by creating a graph of the user’s sleep cycle.

Sample graph of a user's sleep cycle

At the peaks of the graph, the user is most likely at his or her lightest sleep. The user sets an alarm for what time he or she would like to wake up. Within the last thirty minutes of a night’s sleep, Sleep Cycle will analyze the peaks of the graph and will attempt to wake the user gently when he or she is exhibiting a peak of high activity (ie: experiencing light sleep).

Customer reviews express some mixed results with this application, but overall, it appears that many people have positive experiences with Sleep Cycle. Some users report that when the application works properly, they feel wonderful when they wake up rather than being ripped out of deep sleep or a dream when the alarm goes off.

Although this application is only useful for iPhone and iPod Touch users, it is fairly inexpensive at 0.99 cents, and it has the potential to help extremely deep sleepers.

Sleep Cycle – Maciek Drejak Labs
Best Mobile Alarm App: Sleep Cycle - Lifehacker