The locus coeruleus is becoming a major area of research interest, with many important roles like regulating our attention and sleep.
Anyone with insomnia knows the impatience and frustration of sleeplessness, as you struggle to quiet your mind and silence its inner voice. You wish for a button or dial that could instantly calm all that mental activity.
The idea of a mental dimmer switch isn't as far-fetched as it might seem. Most neuroscientists now agree that our wakefulness exists on a kind of continuum. It is managed by a complex network of brain regions, at the center of which is a tiny bundle of neurons known as the "locus coeruleus," Latin for "blue dot."
This is a literal description: the neurons in the locus coeruleus are dyed sapphire blue due to the production of a specific neurotransmitter, called norepinephrine. This is also a clue to the blue dot's function, as norepinephrine controls our physiological and psychological arousal.
For a long time, scientists thought the locus coeruleus was inactive during sleep, but it's now clear that it is never completely silent, with low levels of intermittent activity that may regulate the depth of our sleep. A better understanding of this process may help treat the disturbed sleep associated with conditions like anxiety. The brain's gear system
The locus coeruleus is located in the brain stem, just above the back of the neck, and contains about 50,000 cells, a small fraction of the 86 billion neurons in the average central nervous system. Marie Antoinette's physician, Félix Vicq d'Azyr, first noted its existence in the late 18th century, but it didn't attract much attention for a long time.
This began to change in the 20th century when it was discovered that the blue pigment of the locus coeruleus plays a key role in brain signaling. Norepinephrine (also known as noradrenaline) increases the likelihood that a neuron will "spike" with an electric current. When active, cells in the locus coeruleus send bundles of this neurotransmitter along their projections to other brain regions, enhancing communication between neurons in those areas.
There are nuances to this process. Depending on their receptors, some neurons are more sensitive to small amounts of norepinephrine, while others only respond to higher levels. This means that as the activity of the locus coeruleus increases, it affects some brain areas more than others, which can significantly impact our focus, concentration, and creativity.