If you have been at work or school and are struggling to remember details of things (not always on a specific level but on a general one), your sleep schedule and habits could be the root cause. In fact, the quality and quantity of sleep you get every day will have a direct role in your ability to remember things, as that time is the best period for the brain to consolidate memories.
Why is sleep important anyway?
That does not mean sleep is the most understood subject. It has been a mystery to many scientists and people in general for centuries, although, in the midst of the vague nature of sleep, one thing is understood – memories are always consolidated and entrenched in the mind. Many research efforts are directed at studying this area, and they all seem to agree that sleep is very useful when it comes to certain memories, not all.
Contrary to what you may think, the brain still remains active even when you are asleep. Certain regions are at their most active state, and they are the amygdala, the hippocampus and the neocortex, which also happen to be the most effective at handling memory. However, it is not clear how sleep influences other skillsets, for example, motor procedures. In addition, responses to stimuli and making associations between two stimuli are not strongly related to sleep, although it may end up helping them in some form.
For neuroscientists, they all seem to conclude that sleep assists both qualitative and quantitative alterations of memory. What this means is that memories tend to change before you go to sleep an afterward, and scientific studies all seem to confirm this assertion because they notice the brain does synaptic connection changes as someone is asleep.
How to look at memory differently
If you think about it, memory is not just one – it has three parts. These are recalling, acquisition, and consolidation. These also happen at different times of the day, depending on whether you are awake or asleep.
When you are awake, the brain will recall and acquire new memories, which can be sourced from anything around you and your interactions with the environment. When you are asleep, the brain then consolidates these memories and removes the ones it does not need (pruning them out).
Consolidation mainly involves pruning the memories and then moving them from the ‘buffer-like’ short-term memory into the long-term one, as well as updating any general knowledge and beliefs using the new memories that are coming in. Think of it as similar to the operation of a computer – the RAM memory (short-term) is moved to the ROM (long-term) when you switch off the computer.
All memories appear to center themselves and become formed in three sleeping stages – REM sleep, deep sleep, and light sleep. However, the evidence of the type of memory formation during each of these stages is not entirely clear, as the three stages may be qualitatively different from each other.
How the brain selects memories
Another interesting aspect of memory is the fact that the brain does not pick everything and stores it – it tends to do what is commonly known as ‘cherry picking.’ What happens is that it will use a process of selecting memories and cementing them as long-term memory as you sleep.
The neocortex and hippocampus regions of the brain are the most likely regions to perform the job, although they do it in slightly different ways. For instance, the hippocampus is responsible for keeping special representations that help in episodic memory, and the neocortex will handle all overlapping representations that help you to understand patterns quickly and efficiently. All of this leads to semantic memory.
What this means is that you can look at memories in two ways. Short-term memories are more of specific patterns of activity within the neurons, and long-term memories are more of changes to the structure of your brain, through the formation of more persistent synapses instead of temporary ones. This can also explain if you have a case of short-term amnesia without the wiping out of long-term memories.
In fact, during the consolidation stage, the brain strengthens certain neural connections while erasing others so that new memories can be created. This is particularly during the deep sleep phase (stage 3), where the brain will move memories from the hippocampus (short-term) to the neocortex (long term). When you are awake though, not much activity happens between these two regions, so the neocortex will replay these memories within itself.
This consolidation stage might help in explaining the problem of patients who have conditions such as Schizophrenia, Alzheimer’s as well as fibromyalgia – they have higher chances of experiencing abnormal quality and quantity of no-REM sleep and stage 2 sleep, which makes their brain have greater challenges in forming and consolidating memories.
Conscious experience and neurotransmitters
Whenever you feel stressed, the chemical cortisol stops the information flow between the neocortex and hippocampus. This changes the content of your dreams in general, which can explain why stress is a hindrance to many people when they try to learn conceptual material that is challenging.
When you sleep, the memory transfer is more efficient, and the consolidation occurs in form of dreams. These dreams are highly influenced by the activities of the previous day, as well as other things. It is also interesting to note that non-REM sleep tends to have fragmentary drams and memories, while REM dreams tend to have more cohesion, almost cinematic in their scope.
The reason why lack of proper sleep affects the formation of memories is also due to the chemical adenosine, which means that people who are alcohol drinkers, as well as those suffering from insomnia, tend to have many sleep interruptions. Prescription sleeping pills are also a contributor to lack of consolidation of memories.
The information regarding sleep and memory retention is still a case study, as the facts are not completely clear. What is clear though is that you cannot discount the importance of healthy sleep habits, whether you use a mattress from Tuft & Needle or not – they are not the only key in the maintenance of health, but also in learning new things and boosting your memory of events.