Learned helplessness in flies and the roots of depression

Apr 18, 2013
Learned helplessness in flies and the roots of depression
When faced with impossible circumstances beyond their control, animals, including humans, often hunker down as they develop sleep or eating disorders, ulcers, and other physical manifestations of depression. Now, researchers reporting in the Cell Press journal Current Biology on April 18 show that the same kind of thing happens to flies. Credit: Current Biology, Yang et al.

When faced with impossible circumstances beyond their control, animals, including humans, often hunker down as they develop sleep or eating disorders, ulcers, and other physical manifestations of depression. Now, researchers reporting in the Cell Press journal Current Biology on April 18 show that the same kind of thing happens to flies.

The study is a step toward understanding the for depression and presents a new way for testing , the researchers say. The discovery of such symptoms in an insect shows that the roots of depression are very deep indeed.

"Depressions are so devastating because they go back to such a basic property of behavior," says Martin Heisenberg of the Rudolf Virchow Center in Würzburg, Germany.

Heisenberg says that the idea for the study came out of a lengthy discussion with a colleague about how to ask whether flies can feel fear. Franco Bertolucci, a coauthor on the study, had found that flies can rapidly learn to suppress innate behaviors, a phenomenon that is part of learned helplessness.

The researchers now show that flies experiencing uncomfortable levels of heat will walk to escape it. But if the flies realize that the heat is beyond their control and can't be avoided, they will stop responding, walking more slowly and taking longer and more frequent rests, as if they were "depressed."

Intriguingly, female flies slow down more under those than males do. It's not clear exactly what that means, but Heisenberg explains, "if we realize that the fly trapped in a strange, dark box, unable to get rid of the dangerous heat pulses, has to find a compromise between and not missing any chance of escape, we can understand that such a compromise may come out differently for , as their resources and goals in life are different."

Heisenberg's team now intends to explore other questions, such as: How long does the flies' depression-like state last? How does it affect other behaviors, like courtship and aggression? What is happening in their brain? And more.

Heisenberg says that the findings are a reminder of a lesson that children's books are often best at showing: "Animals have lots in common with us humans. They breathe the same air, share many of the same resources, actively explore space, and have distinct social roles. Their brains serve the same purpose, too: they help them to do the right thing."

Explore further: East African honeybees are safe from invasive pests... for now

More information: Current Biology, Yang et al.: "Flies Cope with Uncontrollable Stress by Learned Helplessness." dx.doi.org/10.1016/j.cub.2013.03.054

Related Stories

European dung-fly females all aflutter for large males

Apr 13, 2012

European and North American black scavenger flies – also called dung flies as their larvae develop in the feces of vertebrates and thus break them down – belong to the same species. Nevertheless, ...

Study finds courtship affects gene expression in flies

Jan 12, 2011

Biologists at Texas A&M University have made an important step toward understanding human mating behavior by showing that certain genes become activated in fruit flies when they interact with the opposite sex.

Recommended for you

Male monkey filmed caring for dying mate (w/ Video)

4 hours ago

(Phys.org) —The incident was captured by Dr Bruna Bezerra and colleagues in the Atlantic Forest in the Northeast of Brazil.  Dr Bezerra is a Research Associate at the University of Bristol and a Professor ...

Orchid named after UC Riverside researcher

22 hours ago

One day about eight years ago, Katia Silvera, a postdoctoral scholar at the University of California, Riverside, and her father were on a field trip in a mountainous area in central Panama when they stumbled ...

In sex-reversed cave insects, females have the penises

Apr 17, 2014

Researchers reporting in the Cell Press journal Current Biology on April 17 have discovered little-known cave insects with rather novel sex lives. The Brazilian insects, which represent four distinct but re ...

Fear of the cuckoo mafia

Apr 17, 2014

If a restaurant owner fails to pay the protection money demanded of him, he can expect his premises to be trashed. Warnings like these are seldom required, however, as fear of the consequences is enough to ...

User comments : 7

Adjust slider to filter visible comments by rank

Display comments: newest first

beleg
2 / 5 (4) Apr 18, 2013
A basic tenet of science is control.
Synergy is where control is shared for better or worst.
Perhaps shared helplessness - male/male, male/female, female/female will change outcomes already known for individuals.
VendicarE
2.3 / 5 (3) Apr 18, 2013
This happens in the real world as well.

In America the Republican states have become helpless and are parasites on the productive Democratic states.

RobertKarlStonjek
3.3 / 5 (3) Apr 18, 2013
The implicit assumption is that all depression has the same cause. Other universals include low brain serotonin levels.

In all cases, any symptom of depression can be the cause or the consequence of depression e.g. a person experiencing depression because of low serotonin will also experience learned helplessness and a person who experiences learned helplessness will also have low serotonin levels. There are other symptoms of depression that have the same kind of dual role.
Torbjorn_Larsson_OM
5 / 5 (1) Apr 19, 2013
Ouch, political trolling.

@RKS: It is an evolutionary constraint, so seeing the homologous traits tests basic biology. This has passed the ad hoc "assumption" (constraint) case.

I don't think they have checked serotonin, assuming flies use it. But I may be wrong.
beleg
1.7 / 5 (3) Apr 19, 2013
Is there an alternative to helplessness in the face of the impossible - (impending, immediate, and inevitable death in this experiment?)
Synthetically manipulating chemical composition to change a state of helplessness to any other state in the face of imminent, immediate, inevitable and impending death does not make sense to me. As if alternating a state arising naturally from an unavoidably outcome is preferred to a natural response (state). Is fear followed by resignation followed by despondence follow by helplessness an aversion in the face of immediate death?
RobertKarlStonjek
not rated yet Jun 01, 2013
@Torbjon
Depression is a very specific condition in humans as is learned helplessness.

Importantly, the two are separate conditions and it is easily possible for them to occur separately ie depression without learned helplessness and learned helplessness without depression.

Thus the fly study and human depression are unrelated or, if they are elated, the study has done nothing whatsoever to establish a connection.

They have simply made the assumption that 'learned helplessness' and depression are linked. They aren't, at least they are not linked in the DSM IV TR, DSM V or the IDC 10, which are the manuals used throughout the world to identify depression.

Thus the study is wrong in making any connection without first establishing if the two conditions are connected and if so, how. It is extremely unlikely that flies have a subjective emotional state comparable to depression and if that is proposed, then that is a philosophical and not a scientific proposal...
beleg
not rated yet Jun 01, 2013
The serotonin theory superseded:
http://medicalxpr...ide.html

Still, I insist you adhered to your beliefs. Readers need entertainment.

More news stories

Researchers successfully clone adult human stem cells

(Phys.org) —An international team of researchers, led by Robert Lanza, of Advanced Cell Technology, has announced that they have performed the first successful cloning of adult human skin cells into stem ...

Scientists tether lionfish to Cayman reefs

Research done by U.S. scientists in the Cayman Islands suggests that native predators can be trained to gobble up invasive lionfish that colonize regional reefs and voraciously prey on juvenile marine creatures.

Researchers develop new model of cellular movement

(Phys.org) —Cell movement plays an important role in a host of biological functions from embryonic development to repairing wounded tissue. It also enables cancer cells to break free from their sites of ...

Continents may be a key feature of Super-Earths

Huge Earth-like planets that have both continents and oceans may be better at harboring extraterrestrial life than those that are water-only worlds. A new study gives hope for the possibility that many super-Earth ...

Under some LED bulbs whites aren't 'whiter than white'

For years, companies have been adding whiteners to laundry detergent, paints, plastics, paper and fabrics to make whites look "whiter than white," but now, with a switch away from incandescent and fluorescent lighting, different ...