• Tiny worms make complex decisions, too

    From ScienceDaily@1:317/3 to All on Monday, March 07, 2022 21:30:48
    Tiny worms make complex decisions, too
    Scientists surprised to discover flexible decision-making capabilities in
    a worm with just 302 neurons

    Date:
    March 7, 2022
    Source:
    Salk Institute
    Summary:
    How does an animal make decisions? Scientists have spent decades
    trying to answer this question by focusing on the cells and
    connections of the brain that might be involved. Scientists are
    taking a different approach -- analyzing behavior, not neurons. They
    were surprised to find that worms can take multiple factors into
    account and choose between two different actions, despite having
    only 302 neurons compared to approximately 86 billion in humans.



    FULL STORY ==========================================================================
    How does an animal make decisions? Scientists have spent decades trying to answer this question by focusing on the cells and connections of the brain
    that might be involved. Salk scientists are taking a different approach -- analyzing behavior, not neurons. They were surprised to find that worms
    can take multiple factors into account and choose between two different actions, despite having only 302 neurons compared to approximately 86
    billion in humans.


    ==========================================================================
    The findings, published in Current Biology on March 7, 2022, have
    important implications for the way researchers assess motivation and
    cognitive abilities in animals. What's more, the study demonstrates that complex decision-making capabilities could be encoded in small biological
    and artificial networks.

    "Our study shows you can use a simple system such as the worm to
    study something complex, like goal-directed decision-making. We also demonstrated that behavior can tell us a lot about how the brain works,"
    says senior author Sreekanth Chalasani, associate professor in Salk's
    Molecular Neurobiology Laboratory. "Even simple systems like worms
    have different strategies, and they can choose between those strategies, deciding which one works well for them in a given situation. That provides
    a framework for understanding how these decisions are made in more complex systems, such as humans." Whether eating prey or defending its food
    source, the predatory worm Pristionchus pacificus relies on biting. The
    team's challenge was to determine the worm's intentions when it bites.

    The researchers found that P. pacificus chooses between two
    foraging strategies for biting its prey and competitor, another
    worm called Caenorhabditis elegans: 1) predatory strategy, in which
    its goal for biting is to kill prey, or 2) territorial strategy, in
    which biting is instead used to force C. elegans away from a food
    source. P. pacificuschooses the predatory strategy against larval
    C. elegans, which is easy to kill. In contrast, P. pacificus selects
    the territorial strategy against adult C. elegans, which is difficult
    to kill and outcompetes P. pacificus for food.

    To the team, it appeared that P. pacificusweighed the costs and benefits
    of multiple potential outcomes of an action -- behavior that's familiar
    in vertebrates but unexpected in a worm.

    "Scientists have always assumed that worms were simple -- when
    P. pacificus bites we thought that was always for a singular predatory purpose," says first author Kathleen Quach, a postdoctoral fellow in Chalasani's lab. "Actually, P.

    pacificus is versatile and can use the same action, biting C. elegans,
    to achieve different long-term goals. I was surprised to find that P.

    pacificuscould leverage what seemed like failed predation into successful
    and goal-directed territoriality." In the future, the scientists would
    like to determine which of P. pacificus' cost-benefit calculations are hard-wired or flexible. They hope more research like this will help
    further uncover the molecular underpinnings of decision- making.

    The research was supported by the National Institutes of Health
    (5R01MH113905), the W.M. Keck Foundation, the National Science Foundation,
    Salk Women & Science and a Paul F. Glenn Foundation Postdoctoral
    Fellowship.

    ========================================================================== Story Source: Materials provided by Salk_Institute. Note: Content may
    be edited for style and length.


    ========================================================================== Related Multimedia:
    * C._elegans_worm_escaping_the_predatory_P._pacificus_worm ========================================================================== Journal Reference:
    1. Kathleen T. Quach, Sreekanth H. Chalasani. Flexible reprogramming of
    Pristionchus pacificus motivation for attacking Caenorhabditis
    elegans in predator-prey competition. Current Biology, 2022; DOI:
    10.1016/ j.cub.2022.02.033 ==========================================================================

    Link to news story: https://www.sciencedaily.com/releases/2022/03/220307113024.htm

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