Everything happens on our body for a good reason, don't matter if it hurts
No one really goes to sleep in order to "rest him/herself" - we all sleep to dream, or else we would never keep our sanity much longer
At first, you wake up. Lots of boring things happen in the meantime between the sleep and the wake up, such as the task of "registering on your memory" the phone number from someone, seeing an uncompleted piece of newspaper floating on the windy city and some cute (but temporary) people to look at
But, let's say... an unexpected and very good things happens. On your commute, an avalanche of Southern Butterflies begins to fly around you, because you were one of them in a past life, probably. You get very emotional about this
Now, let's see how these everyday details are being registered on your brain
Nothing that we do learn during a day is automatically "fixed" on our memory - first of all, the fragments of knowledge are sent to an important and hard-working part of our brain called limbic system (it's the blue thing on the image above)
Obviously, both the Flying Butterflies and the Phone Number are "inside" the limbic system, as well as all the other HUNDRED things you've involuntarily registered while you eyes were open. The limbic system, though, is extremely limited and it only has space to accumulate a single day of useless (or not) information. When it's about to get full, we begin to feel on ourselves a delicious thing:
SLEEPINESS! Whenever you feel sleepy, it does not mean you're physically tired: It's just your limbic system; it's screaming to you "please, please, empty me, I want to learn more things!"
When you're sleeping, the cleaning begins to happen. The limbic system is very, very selective about what kind of info it wants to discard into the darkness of forgetfulness and what it'll send to the cortex (the magenta thing on this picture), the ultimate center of our brain, where all the information are PERMANENTLY PLACED.
Because of this, the limbic system will only send things to the cortex if these information contains at least a fair dose of emotional bias, if that information were received by you with a huge pleasure, sadness, surprise, etc... or, even, through hard work
And this is how it's worked, on the Butterflies. Therefore, it's became an everlasting memory
This process of memorizing something (forever) only happens while we're sleeping.. and it's a good thing, because it requires a lot of our brain, considering that, once an information is being digested by ourselves, a whole network of neurons need to be reconfigured in order to "welcome" new ideas and concepts,
and it's very TRAUMATIC! Your eyes begin to roll at full speed (that's why the neuron rearrangement happens on the REM (Rapid Eye Movement) sleep), you brain begins to work at full speed, even more than when you're concentrated in a book.. and it does a LOUD, LOUD NOISE
Also known as Dream! Remember, we sleep to dream, nothing else
What have you dreamed tonight?