Introducing the brain: creating sharp attention (Introduction)

by David Turell , Friday, January 07, 2022, 18:11 (1049 days ago) @ David Turell

The mechanism is explored:

https://medicalxpress.com/news/2022-01-brain-focus-attention.html

"How can we shift from a state of inattentiveness to one of highest attention? The locus coeruleus, literally the "blue spot," is a tiny cluster of cells at the base of the brain. As the main source of the neurotransmitter noradrenaline, it helps us control our attentional focus. Synthesizing evidence from animal and human studies, scientists at the Max Planck Institute for Human Development and the University of Southern California have now developed a novel framework describing the way the blue spot regulates our brain's sensitivity to relevant information in situations requiring attention.

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"...when a car you did not notice suddenly honks, you are readily able to redirect your attention and respond to this new situation. But how does the brain shift from a state of inattentiveness to one of focused attention?

"During states of inattentiveness, our brains are governed by slow, rhythmic fluctuations of neural activity. In particular, neural rhythms at a frequency around 10 Hertz, termed alpha oscillations, are thought to suppress the active processing of sensory inputs during inattentiveness. Thus, alpha oscillations can be understood as a filter that regulates our brain's sensitivity for external information.

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"To explore this question, the researchers focused on the blue spot (locus coeruleus), a tiny cell structure that is located in the brainstem, hidden deep under the cortex. This cell cluster is only about 15 millimeters in size, but it is connected to most of the brain via an extensive network of long-ranging nerve fibers. The blue spot is made up of neurons that are the main source of the neurotransmitter noradrenaline. By regulating neural communication, noradrenaline contributes to the control of stress, memory, and attention.

"'Due to its small size and its location deep in the brainstem, it was previously almost impossible to investigate the noradrenergic nucleus non-invasively in living humans. Fortunately, over the past years, animal research has revealed that fluctuations in pupil size are linked to the activity of the blue spot. Thus, our eyes can be regarded as a window to a brain region that long seemed inaccessible," says Mara Mather, professor of Gerontology at the University of Southern California and coauthor on the opinion article.

"To study whether the blue spot's noradrenaline could be one factor regulating alpha oscillations, the researchers combined recordings of pupil size and neural oscillations while participants solved a demanding attention task. As expected, during moments of larger pupil size, indicative of higher noradrenergic activity, alpha oscillations disappeared. Moreover, participants who showed stronger pupil and alpha responses were better at solving the attention task. These findings, that were published 2020 in an article in the Journal of Neuroscience, suggest that by modulating alpha oscillations, the blue spot can help us focus our attention.

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"Assembling the findings across studies, we were able to describe how noradrenaline and the thalamus might interact to control alpha rhythmic activity. We suggest that the blue spot's noradrenaline regulates our brain's sensitivity to process relevant information by suppressing alpha generators in the thalamus," says Martin Dahl, postdoctoral researcher at the Center for Lifespan Psychology, Max Planck Institute for Human Development, and the University of Southern California and first author on the opinion article.

"Thus, during situations requiring a sudden shift in attention, a surge of noradrenaline helps us refocus—and quickly dodge the approaching car."

Comment: this process developed in deep time in all brained animals living in a setting that required constant awareness. Our lives do not require that constant degree of awareness all the time, but the mechanism has not devolved under the designer of evolution. Even in ourv relatively calm world my barn cat, even when with me, shows constant vigilance.