My passion for fruit
fly pushes me to look for a peer review journal on flies that I want to share
with you. We all know that as people age, they tend to have memory dysfunctions
and their learning ability decrease. To study the effect of age on learning, a
researcher, Eric Le Bourg, did some experiment on fruit- fly Drosophila
melanogaster to see the relationship between age and learning. He chose flies
because they have a short life span and they can study many generations and
also they have a well-known genetics. This journal article studies the effects
of aging on learned suppression of photopositive tendencies in Drosophila
melanogaster. To begin his experiment, the researcher makes the hypothesis that
as flies age, the ability to learn decreases. To test his hypothesis, he
proceeded to three different experiments. He used light as a conditioned stimulus
associated an aversive unconditioned stimulus, the taste of quinine, and the
darkened arm which was not associated with an aversive stimulus. It turned out
that flies run away from light to avoid the quinine. He pointed out that
quinine does not induce sensitization and has been used for many decades in
learning studies using D. melanogaster because of its bitter taste.
The first experiment
tested whether flies of different ages can avoid lighted
vial associated with an aversive stimulus. The second tested if they can avoid
the lighted vial associated with a strong (quinine) or weak (distilled water)
aversive stimulus. Before both experiment, half of the flies were subjected to
training with the aversive stimulus that will be used in the experiment. In the
third experiment, one half of the flies was subjected to training with a
lighted vial containing a paper wetted with quinine and the other half was
subjected to 16 trials with a lighted vial containing a dry paper and after
that, the same group of flies to 16 training trials with another lighted vial
containing a paper wetted with quinine on each trial.
These experiments have
shown flies of all age learn to avoid the light when it is associated with
quinine or water. Quinine has a bitter taste that flies do not like and the
water prevent them from flying that is why they avoid these two stimuli. However,
the learning score in the older age flies decrease little bit compared to the
first week age flies. Therefore, it can be concluded that age had different
effects on locomotor activity and learning. Old flies walk slower but the
locomotion had a slight effect on learning.
After reading this, my
question is, does this conclusion also apply to human? As we grow old, do we
really get stupid or we know everything but we just don’t want to talk?
Drosophila melanogaster
Click here to read this article
Citation:
Eric Le Bourg, Effects of aging on learned suppression of photopositive tendencies in Drosophila melanogaster, Neurobiology of Aging, Volume 25, Issue 9, October 2004,
Pages 1241-1252, ISBN 0197-4580, 10.1016/j.neurobiolaging.2003.12.004.
(http://www.sciencedirect.com/science/article/pii/S0197458004000326)
