Finding structure in the brain's static
Date:
February 1, 2022
Source:
Cold Spring Harbor Laboratory
Summary:
Researchers found that a monkey's state of attentiveness may be
encoded in the shapes and speeds of slow electrical waves that
course over the surface of the brain. Like a surfer that avoids
smooth water and favors more active waves, the brain uses faster,
choppier waves to process information to which it is paying
attention. By separating how the brain encodes its state of
attention versus stimuli to which it is responding, scientists
hope to understand sleep, anesthesia, attention, and disease better.
FULL STORY ========================================================================== Researchers found that a monkey's state of attentiveness may be encoded
in the shapes and speeds of slow electrical waves that course over
the surface of the brain. Like a surfer that avoids smooth water and
favors more active waves, the brain uses faster, choppier waves to
process information to which it is paying attention. By separating how
the brain encodes its state of attention versus stimuli to which it is responding, scientists hope to understand sleep, anesthesia, attention,
and disease better.
========================================================================== While sleeping, the entire brain rolls through long, slow waves of
electrical activity, like waves on a calm ocean. Researchers call that
state of consciousness "slow wave sleep." Waking up changes the pattern of electrical activity into something that looks more like random noise. But
Cold Spring Harbor Laboratory (CSHL) Assistant Professor Tatiana Engel, Postdoctoral Fellow Yianling Shi, and their collaborators found there
are patterns in the noise.
Looking at the visual processing region of a monkey brain, they
discovered smaller, faster, more localized versions of the large rolling
sleep waves. The shapes and dynamics of these local waves relate to how attentive that part of the brain is. The researchers think that the wave patterns provide an important clue to understanding sleep, anesthesia,
and attention.
The part of the brain involved in visual processing (the visual cortex)
is like a television screen that creates a picture out of a collection
of dots or "pixels." Each brain pixel is composed of a column full of
neurons that act together. Unstimulated columns flicker between being electrically active and sensitive to stimuli ("On") or being inactive
and resistant to electrical activity ("Off"). If visual information
(a stimulus) hits a visual column that is "On," then the information is registered as a large electrical spike. But if visual information hits
a column when it is "Off," then it might not be registered at all.
Engel and Shi, in collaboration with Stanford University Professors
Kwabena Boahen and Tirin Moore, and University of Washington Assistant Professor Nicholas A. Steinmetz, found that when monkeys are paying
attention to a stimulus, the waves get shorter and choppier. "On" and
"Off" states blink through visual cortex columns driven by this stimulus
more quickly and in a smaller area than when the animal's attention
is elsewhere. But why would an awake and attentive brain want to cycle
its columns off and miss information? Engel has a few hypotheses. She
says, "keeping neurons in the 'On' state all the time is energetically
costly. Another reason is that if we were always receptive to information,
we may become overwhelmed; the 'Off' state could help suppress irrelevant information." The discovery that electrical noise changes patterns with different brain states could help researchers understand brain responses
to drugs and disease.
And since primate brains are very good at processing visual information, machine learning researchers might borrow its cleverly structured noise
tricks to improve artificial brains.
special promotion Explore the latest scientific research on sleep and
dreams in this free online course from New Scientist -- Sign_up_now_>>> ========================================================================== Story Source: Materials provided by
Cold_Spring_Harbor_Laboratory. Original written by Eliene
Augenbraun. Note: Content may be edited for style and length.
========================================================================== Journal Reference:
1. Yan-Liang Shi, Nicholas A. Steinmetz, Tirin Moore, Kwabena Boahen,
Tatiana A. Engel. Cortical state dynamics and selective
attention define the spatial pattern of correlated variability
in neocortex. Nature Communications, 2022; 13 (1) DOI:
10.1038/s41467-021-27724-4 ==========================================================================
Link to news story:
https://www.sciencedaily.com/releases/2022/02/220201115149.htm
--- up 8 weeks, 3 days, 7 hours, 13 minutes
* Origin: -=> Castle Rock BBS <=- Now Husky HPT Powered! (1:317/3)