Depression Models: Bite Sci-zed


So I’ve mentioned a few times
before that fruit flies are my favorite model
organism, but last week I read a study that
just made me frown. If my face could
be an emoticon, it would be that one
with the big giant D– that one. This study looked at the
physical manifestations of depression in fruit flies–
those little organisms that I had cooed over and stared at
and force fed wasabi for two years– well, they were showing physical
manifestations of depression in response to uncontrollable,
stressful events, a condition called learned helplessness. I’m a monster. So let’s look at
this a little closer. In the experiment, researchers
stressed out these flies by heating them up. My lab did that, too. Some flies could walk around
freely and they were OK. But other flies, whose
motion was restricted, could not control
their heat exposure and ended up just giving up. They started walking
really slowly and taking really long breaks
and just kind of stopping and giving up. I imagine that if
they could have, they would have shrugged their
little melanogaster shoulders and just sighed. Researchers also noted
that female flies showed more of these depressed
behaviors than male flies. Martin Heisenberg,
lead researcher, responded to this
finding by saying, “If we realized that the fly
trapped in a strange, dark box, unable to get rid of the
dangerous heat pulses, has to find a compromise between
saving energy and not missing any chance of escape,
we can understand that such a compromise
may come out differently from males and females, as their
resources and goals in life are different.” Now, this kind of behavior,
this learned helplessness, is not exclusive to fruit flies. And PopSci pointed
out that there was another paper that came
up this year that looked at harassed, depressed rats. Now, sometimes, this
kind of distress is induced in mice and rats
using a forced swim test. You take a mouse and you put
it into a cylinder of water, and it will start to swim. But if you leave it there
long enough, after a while it realizes that
there’s no way to escape and it just gives up
and stops swimming. You can, after a period of time,
reintroduce the mouse to water, and once again time
the amount of time that it takes for it to give up. Now, this amount of
time– it can be modulated using antidepressant drugs. Because of this,
the forced swim test has sometimes been used
to test the effectiveness of these antidepressant drugs. However, there is
some controversy surrounding how good
of a test it is, as some people argue that
possibly the mice have learned that they’re not going
to get out of the water and so what they’re doing is
conserving energy and waiting for the researcher
to remove them. I will throw in one completely
unscientific side note here that I do recall
watching some of these forced swim test videos in a
class at one point in time. And it was nearly impossible not
to anthropomorphize those mice as just having given up. But back to the study at hand. In February, some scientists
published a new model for looking at
depression in rats. They created a robotic rat which
had three settings, chasing, which was designed to
stress out the rats, and continuous and
intermittent attack, which were designed to
induce pain and fear. They set the robots
to continuous attack and allowed them to harass young
rats once a day for five days. After those young
rats had matured, they were once again
harassed by these robots, this time in either continuous
or intermittent attacks. They found that the rats who
were continuously harassed in their youth,
and then subjected to intermittent attacks
when they moved as adults, showed the greatest
signs of depression. Now, this sounds awful that
scientists have harassed rats into depression,
but it means that we have a potential new model
population of rats, which are mammals like
us, on which we can test the effects of
antidepressant drugs. And we got that population
of depressed rats without having to do any sort
of genetic modification, which could have other
effects on the rats. And while they
still have to test to see just how
close this model is to a model for human
depression, it, to me, sounds like a lot
more plausible way that a human could
develop depression than a forced swim test. Of course, flies and rats
aren’t the only animals in which we find these behaviors. They can be found in
many different areas in the animal kingdom,
including in humans. And so while this may sound like
a pretty depressing topic, what it means is that we potentially
have some new model organisms in flies and rats in which
we can study depression and antidepressant drugs. And so I think that that’s a
topic that might actually hold some hope for a lot of people. Go forth, do science.

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Comments

  1. I wonder if the rats or flies get a ''Pavlov's dog'' type of reaction, by which I mean, if they are placed in the same environment in which they have been tested on, will they show faster signs of depressions than if the environment for testing changes from times to times.

  2. Your presentation, as always, was good. From personal experience I can say that depression sucks. Sometimes trying to maintain a positive mental attitude is not enough and the glass does appear to be half empty.
    Take care little one. #BigUglyMike

  3. You are a "monster" out of not knowing better.
    Those researchers are "monsters" out of curiosity.
    – makes you think what's worse
    – moral and science are often hardly compatible with each other.
    Just like those flies need to find a compromise between saving energy and not missing any escape, we need to compromise between saving our souls and finding new doors of knowledge.

  4. So those researchers' goals is to minder the symptoms of being mobbed. That seems rather tragic. I wish there were more efficient ways to rather deal with mobbing in order to not cause depressions in the first place.

  5. Whaaa…noooo….not the Drosophila 🙁

    Now I feel so bad for them. God knows what mental state my ladybirds were in during my experiments :S

  6. Hey Alex,

    I really like the topics that you've chosen for your last few videos. Admittedly, they have left me with more questions than answers but I'm okay with that. These are important and thought provoking subjects. Keep them coming. 🙂

  7. Interesting and scary thought. However, for this to be true, I imagine we'd have to assume that depression is an intellectual response instead of a natural one.

    Personally, being one who suffers from some mild form of it, I wish depression was a conscious choice so I could stop making that choice, but I know better. Depression isn't a choice. How we handle our depression, that's the choice.

  8. Depression is really hard to measure though, especially in humans. With us you got loads of different types of depression. Physical depression (such as excess heat exposure, like with the files) is one thing, mental/psychological depression (eg loss of a loved one, financial struggles, etc) is something totally different I think.

  9. I really like your teeth, but if I'd had such teeth, my dentist would have definitely told me to get braces. Doesn't your dentist say anything about it? (and if he does, don't get braces, I like them this way)
    P.S.: Do you know that you move your shoulders a lot while you're talking?

  10. I'm grateful for the way you handled this topic. More than the ethics of genetic privacy or de-extinction, this is a sensitive topic. I think you handled it with compassion and a clear head while still maintaining your enthusiasm for science. The result for me was educational without strong emotions, which I think is an impressive accomplishment.

  11. Then I’m lucky since my favorite model organism should be arabidopsis thaliana, and they can’t become depressed, no matter how you treat them.

  12. Certain environmental factors (and only those) cause rats to get depressed. Your "positive" outlook: Now we can test anti-depressant drugs on them!
    My question: Why don't we change our society and reshape environmental factors so neither rats nor humans get depressed in the first place? Leading a balanced life without harassment sounds way better than depending on some pills, even if they were perfected via prior rat-harassment. Sounds like we're giving up on fixing human society D:

  13. So I get the importance of this research but it does leave me a little p.o. I mean this seems cruel to me, even though it isn't really that cruel. But why not just get consent to do similar to things to humans? It doesn't seem fair, we could create similar situations for humans and then watch depression develop in them.

  14. Two little mice fell in a bucket of cream. The first mouse quickly gave up and drowned. The second mouse, wouldn't quit. He struggled so hard that eventually he churned that cream into butter and crawled out

  15. Recently read an interesting study on depression. The data suggests that depression is related to poor communication between brain cells rather than serotonin being too low or oxidized too fast. SSRIs may just be working as a megaphone for you nervous system. Any way, thought it was interesting. Loved the video, as usual. 🙂

  16. No you're a just a troll or an idiot. If you have an infestation, one mouse doesn't matter, so you can set it free.

  17. Is your left eyebrow, darker than the other, I could just be seeing things.
    Anyone else see this as well?

  18. I hope that the antidepressia gets released to actually cure a rat's depression. I've seen rats die of depression, usually after the loss of their comrades, so I'm really looking forward to be able to help that last rat of the pack.

  19. I guess I'm glad someone is doing this sort of research?

    But man, who lays awake at night thinking "I wonder what the best way to cause rats to be depressed is?"

  20. Never had a problem with depression until losing my left leg due to complications from knee replacement surgery and the multiple attempts to fix it. A REAL downer because I had no control. #BigUglyMike

  21. I have depression and whenever I try to research about it it makes me depressed.Thinking about depression usually triggers it. But I was able to watch this and learn about my condition without feeling helpless. Thank you.
    But considering it was about torturing rats to induce depression, I don't feel very good about myself as a person for that.

  22. So the only thing I don't like about these videos is that Alex puts her face as the thumbnail for each of them. It makes me thing she's self-absorbed. The videos themselves are great, but that is just a bit of a turnoff for me.

  23. As someone who has been battling depression my entire adult life, I hope this leads to more effective anti-depressant drugs. There are too many days when mine just aren't effective. It's very frustrating.

  24. I live in a country that allows medicinal marijuana however I'm extremely allergic to marijuana and can't even walk past someone who smells like it without having an uncontrollable asthma attack so, maybe not for me. Thanks for the advice though!

  25. Alex, I think you will find that depression in male drosophila is under-reported. They are socialized from an early age to mask dysphoria and not to talk about it. They do sometimes compensate with increased use of controlled substances, however, so check their hip flasks.

  26. Sorry to say that, but it sort of seem like you have to give up your humanity and empathy to study biology, medicine or psychology.

  27. I guess this is what happens when business drives "science". There are big companies that stand to make a ton of money by selling antidepressants (one of which is currently the #1 best selling drug in the US), hence those are the focus of most research & development. On the other hand, improving society to provide more help to people who are in futile situations probably won't make anyone rich, so there is little funding for studying solutions like that.

  28. Sad or not, it makes perfect evolutionary sense. If you learned that there's nothing you could do to cope with these random negative events, you will eventually stop trying. Because why waste valuable energy on sisyphean endeavors?

  29. The rat swimming test could also be explained in terms of game theory. Now many studies have been done on risk-sensitive foraging (e.g., http://beheco.oxfordjournals.org/content/10/3/338.full)

    where it is shown that when the environment is unpredictable, animals tend to take greater risks to ensure survival, rather than taking less risks and employing strategies where they KNOW they will fail.

    In the case of the swimming rats, they are simply taking the riskier strategy where there is a chance that they will be rescued by the hand that dropped them into the pool vs. the less risky strategy of swimming which provides the added drawback of energy expenditure

  30. The rat thing makes sense. The rat can't continue to fight. When the researcher rescues them, they might start to equate stopping the struggle with being saved. Eventually they just don't even try because it's not with fighting if giving up will lead to rescue sooner. Not a well formed study in my opinion.

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