Transcription
Translator: Ammar Alqatari
Reviewer: khalid marbou
It is 4 AM, and the big test is 8 hours away, followed by a piano recital. You have been studying and practicing for days, but you are still not ready for either. So what do you do? You could have another cup of coffee and spend the next few hours cramming and practicing. But believe it or not, you might be better off closing the books, stopping the music, and getting some sleep.
Sleep takes up about a third of our lives, but many of us give it very little attention. This neglect is the result of a major misunderstanding. Sleep is not wasted time, or a way to rest after all the important work is done. On the contrary, it is a fundamental process, during which the body balances and adjusts its vital systems, affecting breathing and regulating everything from circulation to growth to immune response.
Great, but you can take care of all those things after the test, right? Well, not quite. Sleep turns out to be essential for your brain too, as one-fifth of your body's blood is sent to it as soon as you fall asleep. And what happens in your brain while you are sleeping is a period of intense activity of restructuring necessary for memory function.
At first glance, our ability to remember doesn't seem very impressive. A 19th-century psychologist, Hermann Ebbinghaus, demonstrated that we typically forget 40% of new information within the first 20 minutes, a phenomenon called the "forgetting curve." But this loss can be prevented through memory consolidation, the process by which information is transferred from fleeting short-term memory to more stable long-term memory.
This consolidation happens with the help of a crucial part of the brain, known as the hippocampus. Its role in forming long-term memories was demonstrated in the 1950s by Brenda Milner in her research with a patient known as "H.M." After his hippocampus was removed, H.M.'s ability to form short-term memories was impaired. However, he was able to learn physical tasks through repetition. Due to the removal of his hippocampus, H.M.'s ability to form long-term memories was also impaired.
What this case revealed, among other things, is that the hippocampus is specifically involved in consolidating long-term declarative memories, such as the facts and concepts you need to remember for the test, more than procedural memory, such as the finger movements you need to master for that recital. Milner's findings, along with the work of Eric Kandel in the 1990s, have given us our current model of how this consolidation process occurs.
Sensory data is initially recorded and temporarily stored in neurons as short-term memories. From there, it is transferred to the hippocampus, which strengthens and enhances neurons in that cortical area. Due to this phenomenon of neuroplasticity, new synaptic buds form, allowing for new connections between neurons, and strengthening the neural network, where the information will return as long-term memories.
So why do we remember some things and not others? Well, there are several ways to influence the size and effectiveness of memory retention. For example, memories formed during times of intense emotion, or even stress, will be better recorded due to the hippocampus's connection to emotions. But one of the most important factors involved in memory consolidation, as you might have guessed, is a good night's sleep.
Sleep consists of four stages, the deepest being known as slow-wave sleep and rapid eye movement (REM). Electroencephalogram (EEG) machines that monitor people in these stages have shown electrical impulses moving between the brainstem, hippocampus, thalamus, and cortex, which act as transfer stations for memory formation. And the different stages of sleep have been shown to help consolidate different types of memories.
During slow-wave sleep without rapid eye movements, declarative memory is encoded in a temporary location in the anterior part of the hippocampus. Through continuous dialogue between the hippocampus and the cortex, it is replayed multiple times, driving its gradual redistribution for long-term storage in the cortex. REM sleep, on the other hand, with its similarity to waking brain activity, is associated with the consolidation of procedural memories.
Based on studies, sleep three hours after memorizing your equations and one hour after practicing your music would be most ideal. I hope you now see that neglecting sleep not only harms your long-term health but also reduces the likelihood that you will retain all the information and practice from the previous night. This is confirmed by the adage, "Sleep on it." When you consider all the restructuring and new connection formation that occurs during your slumber, you can even say that adequate sleep will make you wake up each day with a new and improved brain, ready to face the challenges ahead.