We know that sleep is beneficial for the body and mind. We also know that sleep helps us remember. But it also helps us forget. It's confusing, yes. All of this is due to the brain.
We know quite a lot about the brain, but there are still many mysteries. Today we will tell you about a small brain structure called the locus coeruleus and its great significance for us.
The history of the locus coeruleus
In the late decades of the 18th century, the French pathologist Félix d'Azur described a small (about 2 cm) blue spot in the tissue of the brainstem.
In the 19th century, this brain structure, a collection of neurons, received its name – locus coeruleus. The term comes from Latin and literally means "blue spot". It owes its name to its unusual blue color.
In the second half of the 20th century, scientists finally understand that the blue color is due to a pigment resulting from a chemical reaction involving the neurotransmitter norepinephrine.
What does the locus coeruleus do?
In short – it commands. Although small, the locus coeruleus successfully sends signals to the entire brain, including the spinal cord. Its main function is to regulate the secretion of norepinephrine.
Norepinephrine is a molecule that, in addition to stimulating neurons and keeping them "awake," is responsible for a number of processes such as attention, arousal, awareness, processing of emotions, the processes of remembering and forgetting, and the regulation of stress and anxiety.
It turns out that the miniature locus coeruleus is of exceptional importance for the diagnosis of neurocognitive diseases such as Alzheimer's and Parkinson's disease. In their earliest phases, a reduced number of neurons in the locus coeruleus is observed, indicating the presence of a degenerative process.
What is the relationship of the locus coeruleus with sleep?
- Activity and sleep disturbances
Research on the locus coeruleus is difficult due to its small size and its location – too "deep" in the brain to be easily observed. However, thanks to new technologies in magnetic resonance imaging, this is becoming more accessible.
One of the major conclusions of modern scientists is that the more active the locus coeruleus is during the day, the worse the quality of sleep, including the intensity of REM sleep. Interestingly, this phenomenon worsens with age. Studies show that people between the ages of 50-70 exhibit higher levels of activity in the locus coeruleus during the day, which explains why insomnia occurs with age.
- Activity and memory
As mentioned above, the locus coeruleus regulates the secretion of norepinephrine. This, in turn, is responsible for a number of processes, including the processing of new information and its consolidation in our memory.
Sleep has different phases. Generally, they are divided into 3 phases of NREM sleep, among which is deep (the most restorative) sleep and 1 phase – REM sleep. This is when the most intense and vivid dreaming occurs.
Scientists have proven that the locus coeruleus is active during NREM sleep phases, with its activity gradually decreasing. During the REM phase, the locus coeruleus is completely inactive, therefore does not release norepinephrine. This is because in the early phases of sleep, the brain processes and retains necessary information, while during the REM phase it eliminates synapses that it considers unnecessary.
So, we hope you found it interesting, because we certainly did, and we eagerly look forward to learning (and sharing) about more interesting brain structures and exploring their connection to sleep together.
