Our brain and sleep
Our brain and sleep

Which parts of the brain are involved in sleep?

While in the past people believed that sleep was a well deserved break for the brain, we now know that the brain never sleeps. In fact, while we sleep the brain performs important “maintenance” and there is plenty of activity going on inside our heads.

However, different parts of the brain are active in different situations and during the day, while we are awake, the brain shuts down some areas that control sleep and promote sleepiness.

Of course, while we sleep the part of the brain responsible for keeping us awake and alert is inhibited. Even our ability to move is diminished or completely cut off, during different stages of sleep.

Which parts of the brain are involved in sleep?

Research is still ongoing on the anatomy of sleep, and a lot of new information emerges with each and every study. But there is still a lot that we don’t know about.

What we do know is that being awake is a result of the cerebral cortex being stimulated by signals sent by the hypothalamus. The hypothalamus transmits information using neurotransmitters, which are basically chemicals.

The nervous system uses many chemicals to communicate information and some of these are influenced by our actions and by other medical .

For example, those who have allergic reactions sometimes use antihistamine medication. Histamine has many roles in the human body. One of them is to stimulate a state of wakefulness.

 In this context, it is easy to understand why some medication can cause drowsiness.

 There are many parts of the brain that are involved in sleep[1]. The most important are:

  • Hypothalamus
  • The Brain stem
  • The Thalamus
  • The pineal gland
  • The Amygdala
  • The basal forebrain

Let’s take a look at what each part of the brain does for us. It’s always good to know what your employees are doing, even if this particular employee is self-driven.

The Hypothalamus

This small part of the brain, situated right in the middle of the gray matter, acts like a center of command. It isn’t involved just in sleep, it has a lot more important tasks.

This specialized part of the brain in in charge of controlling body temperature, regulating hormones and emotions. It also manages blood pressure, appetite and thirst and it regulates the circadian rhythm and sleep cycles.

The hypothalamus receives signals from the eyes, and interprets them to decide if it has to stimulate other brain regions to begin the sleep cycle.

This is an essential element…maybe that is why it’s hidden so deep inside our brain.

The Brain stem

The Brain stem lies between the head and the neck. It represents the connection between the brain and the spinal cord. You would think that it’s only role is to transmit information. But it has a much more complicated job, being responsible for many essential functions.

The Pons and Medulla are the parts of the brain stem that influence sleep. They prompt our muscles to relax and to not move during REM sleep (the one in which we dream).

Scientist believe that this mechanism has evolved in order to protect us from acting out our dreams and getting hurt.

The Thalamus

This part of the brain is relatively dormant during our sleep. But, once we enter REM sleep, and we begin dreaming, the thalamus begins sending us materials for that dream.

It does that because it is able to access information from the short and long term memory. The fact that it is particularly active during REM sleep may be the reason for which this sleep stage has an influence in the way that we process memories and emotions[2].

You can read more about sleep stages and what happens during them here, in the article we dedicated to them.

The Pineal Gland

This small gland has many functions too. It even has power over our bone density.

It influences our ability to sleep and stay asleep by producing melatonin. The Pineal gland does this under the influence of the circadian rhythm that needs daylight to function properly.  

The Amygdala

This is a primordial part of our brain that controls our emotions, including our fight or flight mechanism.

It becomes activated during REM sleep. The amygdala is behind the reason for which our dreams are so vivid, and for which sometimes we feel like everything we dream is real.

If at some point feeling afraid woke you up, you should blame your Amygdala. But, you also need to remember that this function is what gives you better emotional control and a better ability to deal with stressful situations.

The basal fore brain

This is yet another multitasking part of our brain that controls, among other vital things, voluntary movement.

It governs over sleepiness and wakefulness by releasing certain chemicals and influencing how we feel. As with all these systems, the basal fore brain also communicates with the Amygdala to manage sleep drive.

The circadian rhythm and our rhythm

The circadian rhythm is the one that truly controls our sleep. In nature, natural light controls it and most animals depend on it.

However, once our society evolved to depend on artificial light, the circadian rhythm was not able to tune to the “original program”. So, it somewhat adapted to our new requirements.

The sleep-wake homeostasis is a natural process that tells our body when it’s time to sleep or wake up. It is connected to the circadian rhythm and it’s influenced by our brain.

There are different factors that can intervene in the fine balance between these two mechanisms.

Issues like:

  • Disease;
  • Forced sleep patterns (night shifts);
  • Lack of exposure to natural light;
  • Increased exposure to artificial light;
  • Change in time zone.

Once the sleep mechanisms are out of sync the amount and quality of sleep becomes affected. Then, problems such as insomnia, interrupted sleep or feeling tired all the time, will arise.

Luckily, all of these problems can be corrected if they are addressed at the right moment by using the right tools. It is important to know if you are getting enough sleep and if you need help to improve your sleep patterns. The first step is to learn more about what sleep deficiency can lead to.

[1] https://www.ninds.nih.gov/Disorders/Patient-Caregiver-Education/Understanding-Sleep

[2] https://www.physio-pedia.com/Sleep:_Theory,_Function_and_Physiology


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