Sleep, Memory, Personality…

a blog partially written long back on 29-th July

The last few months, something has been bothering me. I feel I have lost some ability to multi-task and to be flexible with the number of topics I could handle at the same time. My mind was becoming slower to assimilate several topics and to work simultaneously on these different topics. I decided that this was because I was sleeping much more. This left me with less time to do all that I wanted to do. Yet, I could not go back to my earlier habits of sleeping less. My body was tired and I wanted my share of sleep. The inability to handle multiple topics also meant I was bored, listless with nothing much to do – with nothing much to do, I could only find meaning in sleeping. This was becoming a vicious cycle.

After a busy holiday, with several things to do, and as a consequence, getting less sleep, I am back home in my relaxed atmosphere. So I decided to see whether I could catch up on my reading habits – attempt number infinity. So here I took my one of the several Scientific American still in the plastic cover it came in. As he saw the titles of the articles in front, my husband remarked – “They are caving in to the popular demand as well”. Two of the cover stories were “How sleep shapes memory” and “Why exercise works wonders” – both topics dealt with to death in mainstream magazines.

The article was far from the frivolous articles in glammags advising “8 hours beauty sleep”. The subject was the research done by Giulio Tononi and Chiara Cirelli on function of sleep on human consciousness.

The article talks about how the brain handles the simulants received during the day, sorts through it and stores the important information based on the contextual memories stored before or because of reinforced signals received during an experience. It depresses the rest of the experiences so that insignificant events do not leave a lasting impression. As a result, the brain is left more free to handle new experiences, form new “important” memories and thus enable us to learn new things each day. Most of the time, this activity occurs when we sleep.

As we sleep, we stop forming new experiences. This leaves the brain more free to digest the information and discern without being disturbed by noise. It helps the brain to identify the right patterns and store the right information. As you start sleeping, the brain actively starts rearranging these simulants and as the night draws on, it stores and discards until finally growing quiet. When you wake up in the morning, you are refreshed, all ready with the baseline brain ready to receive new information.

Suddenly I was concerned. There were a couple of points here that made me wonder about how the brain decides on which is important information.

One was the number of reinforced experiences through the day. If a person has several negative experiences through the day, the brain stores this important information. Later, when sifting through patterns, the brain identifies these negative patterns and store only similar patterns. I could suddenly see a whole new negative person forming with no chance to break out of this until this person had a whole set of positive experiences powerful enough to rewrite those negative memories. How many fold should these experiences be created in order to rewrite? This perhaps formed the basis for all the behaviours passed down generations (both positive and negative) – your brain gets used to behaving the way your family behaved. It almost seemed that during sleep each person was adapting the behaviour they see around them – the behaviour they see most often would get reinforced as a memory that would then form the basis for the learning of permanent behaviour.

The other day at Starbucks in Berlin airport there was a family in front of me. They were waiting at the delivery counter, all smiling. The mother and the daughters took the straws from the extras counter and put in the mouth and started blowing imaginary smoke rings at each other – laughing all the time and trying to have a smoke ring blowing competition. The father collected the drinks, playfully tapped the mother on the head to leave the place and they laughed and left. I imagined a set of very happy human beings 30 years from now – playfully treating all the experiences they face. At the time I did not realize. Today, I while reading the article, I could see their neurons being written with memories of how even waiting times could be a chance to have fun and to laugh. Life would be a game for them.

The article also talks about how when fruit flies spent more time with other fruit flies, their neurons sprouted more synaptic spines (the ones that were later sorted out into memory or discarded) than otherwise. This also meant, the more experiences one made, the more the brain had to sort out. What happens when the experience was so diverse that the brain could not find the patterns? Is it better to have these diverse interactions? I wondered about what effect this would have on extroverts vs. introverts. Would extroverts, who go out and invite external impulses, develop the ability of their brain to sort out diverse types of input in a different way? Would the introverted mind be more used to sorting out similar impulses, within the context of self, much better than the extroverted mind which would perhaps have diverse experiences but not to the depth that the introverted mind? Which was the chicken and the egg? Which was the cause and which the effect – most extroverts were interested in different topics but find it difficult to go into extreme details?

I am one of those people who claims to be able multitask. “I am a woman”, I often claim – “I can multitask”. Yet, there are many times I wonder, can I really? Aren’t there small things I forget when I am doing multitasking? The article also talks about the soup of signaling chemicals (or neuromodulators) in a wakeful person’s mind. While creating this myriad of influences, we might actually be weakening out which memory gets strengthened. So perhaps in all those instances when I multitask, there are jamboree of memories and perhaps not all of them get formed with similar strength. Perhaps, this could also lead me to forget some parts that might be vital.

The recent article in New York times talks about how one might have “memories that never happened”. If you have a myriad of similar impulses could it not be that memory made elsewhere or which someone could partially get strengthened in a different context? It is said a sleep deprived person can adapt by putting those parts of the brain, with more plasticity, to sleep. Hence those people:

“who have been awake for too long, or have overexerted certain circuits, small chunks of the brain may take quick naps without giving notice. One wonders how many errors of judgement, silly mistakes, irritable responses and foul moods result from local sleep in the brain of exhausted people who believe they are fully awake and in complete control.”


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