• Finding structure in the brain's static

    From ScienceDaily@1:317/3 to All on Tue Feb 1 21:30:42 2022
    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

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