How do the locus coeruleus in the brain help us focus quickly?

How do we go from a state of inattention to a state of high concentration? Perhaps related to this is the locus coeruleus, which literally means "locus coeruleus," and is a small cluster of cells at the base of the brain
.

As a major source of the neurotransmitter norepinephrine, it helps us control our attention

Researchers at the Max Planck Institute for Human Development and the University of Southern California have developed a new model that describes how the locus coeruleus modulates our brain's sensitivity to relevant information in situations where attention is required
.

Their findings were recently published in the journal Trends in Cognitive Sciences

Our attention spans are constantly changing
.

Sometimes we get distracted and don't pay attention to what's going on around us, and other times we focus on what's important

In a state of inattention, our brains are controlled by slow, rhythmic fluctuations of neural activity
.

In particular, rhythms with frequencies around 10 Hz, called alpha oscillations, are thought to inhibit active processing of sensory input during inattention

Markus Werkle-Bergner, senior scientist at the Max Planck Institute for Human Development, said: "Although a link has been established between the rise and fall of alpha oscillations and attention, we still don't know much about why these rhythmic firing patterns are constantly changing.
less
.

"

To probe this question, the researchers focused on the locus coeruleus, a tiny cellular structure located in the brainstem, deep beneath the cerebral cortex
.

This cell cluster is only about 15 millimeters in size, but it can connect to the brain through an extensive network of long-range nerve fibers

Professor Mara Mather from the University of Southern California said: "Because of the locus coeruleus' small size and deep location in the brainstem, it was previously almost impossible to perform non-invasive studies in living humans
.

Fortunately, in the past few years, animal studies have demonstrated pupil size Fluctuations in the locus coeruleus are linked to activity in the locus coeruleus

To investigate whether norepinephrine from the locus coeruleus could modulate alpha oscillations, the researchers recorded pupil size and neural oscillations while participants performed a task that required concentration
.

As expected, alpha oscillations disappeared at the moment when the pupils were larger (indicating higher noradrenergic activity)

What remains unanswered in this study, though, is how norepinephrine affects alpha oscillations
.

To address this question, the researchers turned to previous animal studies that directly recorded the neural activity of thalamic neurons
.
The thalamus is an area in the middle of the brain that acts as an alpha pacemaker
.
They found that the rhythmic firing of these neurons at rest caused alpha oscillations in the cerebral cortex, the same oscillations that occur during inattention
.
However, adding norepinephrine to these neurons disrupted their rhythmicity
.

"Combining these results, we were able to describe how norepinephrine and the thalamus interact to control alpha rhythmic activity," said the researchers
.
"We believe that norepinephrine from the locus coeruleus modulates our brain by inhibiting alpha generators in the thalamus.
Sensitivity of processing relevant information
.
”

So in situations where a sudden shift of focus is required, the norepinephrine rush can help us regain focus and quickly dodge an oncoming car
.
In the future, long-term studies evaluating the locus coeruleus and thalamus in the same participants may shed light on the neural mechanisms of attention, and its decline in aging and disease
.

Related literature:

1.
Dahl, MJ, Mather, M.
, & Werkle-Bergner, M.
(2022).
Noradrenergic modulation of rhythmic neural activity shapes selective attention.
Trends in Cognitive Sciences, 26(1), 38–52.
https:// doi.
org/10.
1016/j.
tics.
2021.
10.
009

2.
Dahl, MJ, Mather, M.
, Sander, MC, & Werkle-Bergner, M.
(2020).
Noradrenergic responsiveness supports selective attention across the adult lifespan.
Journal of Neuroscience, 40(22), 4372–4390.
https ://doi.
org/10.
1523/JNEUROSCI.
0398-19.
2020