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

--- up 14 weeks, 5 days, 22 hours, 45 minutes
* Origin: -=> Castle Rock BBS <=- Now Husky HPT Powered! (1:317/3)