Quick: What do sleep and a symphonic work have in common? 
No, this isn't the set-up to a bad joke. In terms of structure and function, both are strikingly similar.
And just like before most concerts, we even have a pre-concert talk by Steve@Zeo, originally part of our Behind the Headband series, to highlight unique features that appear in a nightly performance.
In order to play a symphony, you need an orchestra comprised of different instruments, with a different part of music for each type of instrument.
In order to sleep, your internal organs each need to do different things like, secret melatonin, dial down the digestive system, etc. On top of that, you need different organs to secrete growth hormones to repair body tissue and for neurons to process information and consolidate the important parts into long-term memories during each sleep stage.
But they don't just do this willy-nilly. Just like in a symphony, there's a certain rhyme and reason as to why things happen when they do over the course of a night.
To correctly play a symphony as written, each instrument needs to play the correct movement at the right time; if Beethoven's 5th didn't stat off with it's signature "Dah-Dah-Dah-Dahhhn", the audience would know something was wrong. Similarly, sleep has a distinct type of architecture.
A typical night of sleep is front-loaded deep sleep earlier on in the night (the first movement) while saving the REM for the second and third parts of the night. Light sleep shows up throughout, like an overarching theme, while Wake is the natural breaks and pauses within each piece. 
However, if lots of REM showed up ahead of Deep, or if you just had huge chunks of Wake, then your body would know that something was out of sync, and it would scramble to correct it over the next few nights.
To help keep it all together, there needs to be some overarching direction and guidance. An orchestra has a conductor with a master score while we have the suprachiasmatic nucleus in our brain's pineal gland. But even the best conductor can't be individually conducting each instrumental group--much less each musician.
To compensate, the music score has time indicators as to when each part does their thing. Likewise, our internal organs and cells appear to have their own circadian clocks that move at different times based on different cues.
In an orchestra, you can have a violin section divided into three parts, with all of them playing at once or with each group playing at different times. Our own brain divides itself into sections that fire at different times and frequencies during the night, depending upon the sleep stage and other bodily factors. A good example of this happens when we fall asleep and when we wake up. Certain regions of the brain fall asleep before others, making it tricky for both Zeo and trained sleep technicians to sometimes determine when one's asleep vs awake.
Of course, the more different parts that a single group is playing at once, the harder it becomes to figure out what each individual line sounds like. Sometimes the first and second violins are playing so frantically that one can't hear the third--or even notice that the third violins aren't playing at all. Brain signals work in much the same way, with noisier, higher frequencies sometimes drowning out or suppressing lower ones.
With the potential to miss out on key information, where to put the microphone (or headband) to get the best recording is always a challenge. To learn more about this, stay tuned to our YouTube channel for our next Behind the Headband video. Remember, each video will be posted to YouTube first, so subscribe here to get them early!