• Both early experiences and gene expressi

    From ScienceDaily@1:317/3 to All on Wed Aug 18 21:30:36 2021
    Both early experiences and gene expression influence impulsivity in
    chicks

    Date:
    August 18, 2021
    Source:
    Linko"ping University
    Summary:
    Differences in impulsivity between individuals are linked to both
    experience and gene expression, according to a study on the ancestor
    of domestic chickens, the red junglefowl.



    FULL STORY ========================================================================== Differences in impulsivity between individuals are linked to both
    experience and gene expression, according to a study on the ancestor
    of domestic chickens, the red junglefowl. The study from Linko"ping
    University, Sweden, has been published in the journal Animal Behaviour.


    ==========================================================================
    More impulsive individuals are more likely to respond rapidly to
    situations without planning or considering the consequences. In many
    species, including humans, impulsivity differs between individuals,
    but we do not yet understand why this is, as research into what lies
    behind these differences is limited.

    "Variation in impulsivity is especially puzzling, because individuals with
    high impulsivity can suffer negative consequences, such as taking risks
    without considering the outcome. We expect natural selection over time
    to favour behaviour that benefits the individual, so why do we regularly observe individuals who are considerably more impulsive than others?" asks Hanne Lo/ vlie, associate professor in the Department of Physics,
    Chemistry and Biology at Linko"ping University, who led the study.

    The LiU researchers looked in more detail at how impulsivity could be influenced by underlying factors. They studied the red junglefowl (Gallus gallus), the ancestor of our domestic chickens and a frequently used
    species for studies on behavioural differences and cognition, measuring
    animal "intelligence." To investigate whether junglefowl chicks differed
    in impulsivity, the researchers used an already established test in
    which a reward (a mealworm) is placed inside a transparent tube. The
    impulsive response is to try to reach the reward directly through the
    solid, transparent side of the tube, even though this is not possible. To
    get the mealworm, a chick must instead curb its impulsivity and remember
    what it has previously learnt -- that it can reach the reward from
    the open end of the tube. The researchers counted how many times each
    chick pecked at the transparent tube trying to get the reward, which
    is a measure of how impulsive they were. By repeating the experiment
    several times, the researchers also measured how well each chick learnt
    to reduce its impulsivity.

    The scientists wanted to see how early experiences could influence
    impulsivity.

    Before testing how impulsive chicks were, they assigned each chick at
    random to one of three treatments. In one treatment, chicks received
    training which aimed to improve their cognitive abilities, resulting
    in 'cognitively enriched' chicks. Chicks in the second treatment were
    permitted to interact with the cognitive testing equipment, but were
    not trained themselves, and were thus 'environmentally enriched' (but
    not cognitively enriched). Chicks in the third treatment did not receive
    any enrichment while growing up.

    The results showed that these differences in early experience did indeed
    affect impulsivity in the junglefowl chicks, but not in the manner that
    was expected.

    "Intriguingly, cognitively enriched chicks, who had been trained to pass
    other cognitive tests, were more impulsive than the other chicks. This
    goes against our initial expectations but is compatible with our finding
    that environmentally enriched chicks were slower to learn to reduce impulsivity.

    Thus, all chicks that received enrichment were less able to curb their impulsivity. Our results support discoveries from earlier studies that
    suggest that enrichment can increase impulsivity, and highlight the
    potential role of cognitive enrichment," says Laura Garnham, PhD student
    at LiU and one of the researchers behind the study.

    Variation between individuals was also influenced by brain gene
    expression. The scientists investigated the levels of expression
    of several genes that are involved in two important brain signalling
    systems, the serotonin system and the dopamine system, which in other
    species have been linked to impulsive behaviour.

    "We found that impulsivity correlated with the expression of one gene
    linked to the signalling molecule serotonin, and two genes linked to the signalling molecule dopamine. This shows us that not only differences
    in experience, but also genetic factors can contribute to differences
    in impulsivity between individuals," says Sara Ryding, who worked in the
    study while on an exchange visit from the University of Manchester. Sara
    is now a PhD student at Deakin University in Melbourne, Australia.

    The research has received financial support from the FORMAS research
    council.

    ========================================================================== Story Source: Materials provided by Linko"ping_University. Original
    written by Karin So"derlund Leifler. Note: Content may be edited for
    style and length.


    ========================================================================== Journal Reference:
    1. Sara Ryding, Laura C. Garnham, Robin N. Abbey-Lee, Irina Petkova,
    Anastasia Kreshchenko, Hanne Lo/vlie. Impulsivity is affected by
    cognitive enrichment and links to brain gene expression in red
    junglefowl chicks. Animal Behaviour, 2021; 178: 195 DOI: 10.1016/
    j.anbehav.2021.06.007 ==========================================================================

    Link to news story: https://www.sciencedaily.com/releases/2021/08/210818130553.htm

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