What makes us forget ? Brain Science

Everybody want to have a good memory and we often try to find out how much we can store in our brain memory. Nobody want to forget anything, but our brain is not a hard-disk (as most of the people think about it). Brain is a biologically evolved very advanced supercomputer that remembers a lot of things, but also keeps forgetting somethings, which are considered useless by it. Sometimes we feel that our memory is not performing well only when our brain considers some important things as useless, while those things were actually important. It does not mean that there is some problem with your brain, almost everybody tend to forget where he/she left the keys.

What makes us forget ?

Forgetting is an equally important part of our life, just like remembering. Our sleep plays an important role in our brain functioning. Especially the REM (Rapid Eye Movement) Sleep, when we see dreams and nightmares, is the time when this erasing of unnecessary memory happens. During a good night sleep we enter REM phase of 10-20 minutes around 6 to 8 times. During all those REM phases we see a number of dreams, but we rarely remember even one of them. It is because during that REM sleep our brain keep erasing the memories of those unnecessary dreams / nightmares, so that they don't interfere with real life memory. While erasing those dream memories, our brain also erases some real life memories that are considered useless or unnecessary by it.

In depth about erasing memory

Our dreams are actually screensavers that are played to entertain us while real task of erasing memory is being done. During REM Sleep, hypothalamus releases MCH (Melanin concentrating hormone). Previously researchers thought that MCH helps in building memory but now they have found that during REM sleep MCH erases the dream's memory and also the short term memory that is considered not-important. What makes it categorize the information as important and not-important is also being researched.

Most of us think that neurons store memory, but its not true. Memory storage occurs in the connections between neurons, known as synapses. Each neuron have thousands of synaptic connections with other neurons. During daytime several synapses are created to store new memories, while during REM sleep MCH erases/destroys the unnecessary synapses. One more event occurs during REM sleep, which changes important short-term memory into long-term memory. Some researches suggest that those synapses grew stronger which were accessed again and again, while those remain weak which are never accessed after creation. MCH probably destroys/erases the weaker synapses.

Now if your teacher asks you to revise the lesson, then understand the fact that accessing the same content stored in your memory makes the synapses stronger and don't let your REM sleep erase that important topic that will be asked in exams.

Same thing happens with us when we leave the keys in our jeans pocket, and next morning we shuffle the whole house searching for them. Actually leaving the keys in your pocket usually happens due to a reflex action, but you don't access that memory again and go to sleep, which erases that never accessed memory.

Sleeping is not just a resting process that eases or our muscles, but it is a maintenance phase of our brain. If you don't sleep for days then your brain chemical start to act weird that affects your mental balance and memory. Mankind is discovering the whole universe without even knowing how our brains are storing/retrieving that information and erasing the useless information without even asking us. There is still a lot more to know about our brain to better understand ourselves.