Medically reviewed by
Dacelin St Martin, MD
Triple board-certified in Sleep Medicine,
Internal Medicine, and Pediatrics.
Sleep & Memory | The Science of Memories | Insomnia & Cognitive Functions
Sleep is the body’s natural defense mechanism that helps repair the damaged tissues and heal your stressed mind. What happens when you don’t get enough sleep? A lack of sleep interferes with your body’s ability to repair itself and leads to further damage on a cellular level.
Insomnia has a detrimental effect on your brain. It impairs the brain’s cognitive performance and reduces your memory, attention span, concentration, and problem-solving skills.
Read on to learn more about how insomnia affects your cognitive functions.
Sleep & Memory
There are different types of memories. For example, some memories are based on facts such as the names of state capitals, while some are episodic memories based on events and circumstances in your life.
Instructional or procedural memories help you learn and retain information about performing specific activities, like writing computer programs or playing the piano. 
Any information you learn can become a memory through three functions, including acquisition, consolidation, and recall.
The acquisition stage involves learning something new, while consolidation and recall help the memory to stabilize in your brain. The consolidation of any memory occurs while you are asleep.
Without proper consolidation, any newly acquired information may be lost from your brain’s memory storage and would not be available for recall or use. Thus, without adequate sleep, the brain will have a hard time retaining and recalling memories.
These basic physiological processes indicate why it is vital to ensure you get sufficient sleep every night to improve your memory and cognitive performance.
The Science of Memories
Scientists believe that the hippocampus and neocortex, which are areas of the brain, are where our long-term memories are consolidated and stored.
During sleep, the hippocampus is activated. It replays the events or information learned during the day. This information is reviewed by the neocortex and processed to form stable memories, indelibly placing them in your mind.
The 4th Phase of Sleep: REM
Research studies suggest that certain types of memories become more stable during the REM (rapid eye movement) phase of sleep. REM sleep is the deeper phase of sleep when our mind and body are fully relaxed.
People who have insomnia, disturbed sleep, or sleep apnea wake up frequently due to mental or physiological stress and cannot enter REM sleep. As a result, the memory consolidation processes in the hippocampus and neocortex fail to occur.
Additionally, the lack of sleep may interfere with your learning processes by affecting the brain’s ability to secure memories. This inability to recall information is proof that people who cannot sleep well usually have poor memory and reduced productivity.
Let’s look at how insomnia affects different aspects of cognitive functions.
Insomnia & Cognitive Functions
1) Motor Memories
Research studies show that your sleep can influence procedural memory. Procedural memory, sometimes called motor memory, refers to your ability to learn and adopt physical skills, such as riding a bike or playing instruments. Lack of sleep can affect your motor memory and prevent you from learning new physical skills.
2) Recall Memories
Sleep can improve your ability to recall the information you have learned. Insomnia, on the other hand, can adversely affect your recall memory, causing confusion, fogginess, and disorientation.
3) Declarative Memory
Insomnia may affect your declarative memory, which is your ability to recall facts such as the events, dates, and places you may need to memorize. This inability to remember information may lead to poor academic performance.
Studies also reveal that the memories related to facts learned recently become stronger when the quality and duration of your REM sleep is high.
Advanced brain imaging tests have enabled researchers to assess how exactly sleep deprivation affects the brain’s cognitive functions, including rational thinking.
One research study has shown that sleep deprivation may alter the functional neurons connecting the prefrontal cortex and the emotion and reward processing centers in the brain. This inability of the neurons to connect may impair the brain’s executive functions such as rational thinking and problem-solving skills.
As a result, you may become hypersensitive to a rewarding stimulus, thus heightening your emotional response, leading to irrational thinking and behaviors.
5) Focus and Concentration
Research studies have shown that sleep deprivation can reduce your attention span, focus, and concentration. This sleeplessness could negatively influence academic performance and workplace productivity.  It may also reduce your working memory and increase reaction time. As a result, you may experience difficulties in reacting efficiently and promptly during emergencies.
People who have chronic insomnia are prone to develop degenerative brain disorders such as dementia. Sleep deprivation can cause an increase of amyloid-beta plaques in the brain, thus triggering the development of disease.
Insomnia can accelerate the decline in memory and attention span in patients with Alzheimer’s disease and cause disorientation of time and space at a much younger age.
Your brain processes information collected throughout the day to form memories while you sleep. Sleep deprivation can put you at risk for poor cognitive performance by impairing the brain’s ability to learn or retain new information.
It may also reduce your motor memory, attention span, focus, and concentration. Ensuring you get a sufficient amount of sleep every night can boost the brain’s cognitive functions and improve your memory, rational thinking, and problem-solving skills.
If you have concerns about your sleep, it is always a good idea to speak to your doctor about Cognitive Behavioral Therapy for Insomnia (CBT-I). There are programs accessible online that use CBT-I to teach you how to sleep, without the aid of supplements or sleeping pills.
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