Memory and Sleep

How does the brain process the information and experiences that we have during the day at night when we sleep?


At night, our brain does not follow a simple process of input and then storage, our brain has a complex process that involves many interconnections between the many different neurons in different areas that participate in such a process. This process involves taking the sensory information from our most recent experiences, selecting what is relevant, discarding unnecessary information, and associating all this with other stored information from experiences that we lived before, that is, from information that was previously processed and stored in our brain.

In this process that happens when we sleep, relevant information is “filed” and reorganized in the right place so that we are able to retrieve it when we need it. This action of accessing and retrieving information can be a conscious or subconscious action.

Let’s say a girl is having piano lessons, and she needs to learn and practice a certain melody. Her piano instructor showed her the melody, its rhythm, its sound, etc., however the girl has to practice it so that when she plays the melody at the closing piano ceremony of the end of the year, which is coming soon, it comes out perfect. She tries practicing the day her instructor introduced her to the melody, but she is not comfortable with the outcome, so she doesn’t practice the following 3 days. Then, on the 4th day she practices the melody and she performs incredibly well. What happened? She didn’t practice the melody for a few days and then she does great!!!The explanation to this outcome is that her brain did practice the melody when she was sleeping, she rehearsed and practiced playing the melody in her sleep, for 3 nights. So when she played the melody on the piano while awake, it came out really well, she did practice and rehearsed the melody.

Sometimes the time our brain needs to process daytime inputs in longer periods of sleep, and at different stages of sleep. It is known that the different stages of sleep provide the ideal state to process different kinds of input. This means that some input from one experience may be processed in the immediate sleeping period, while other inputs of the same experience may be processed in later sleeping nights.