So I've mentioned a few times before that fruit flies are
So I've mentioned a few times before that fruit flies are

my favorite model organism, but last week I
my favorite model organism, but last week I

read a study that just made me frown.
read a study that just made me frown.

If my face could be an emoticon, it
If my face could be an emoticon, it

would be that one with the big giant D--
would be that one with the big giant D--

that one.
that one.

This study looked at the physical manifestations
This study looked at the physical manifestations

of depression in fruit flies-- those little organisms that I
of depression in fruit flies-- those little organisms that I

had cooed over and stared at and force fed wasabi for two
had cooed over and stared at and force fed wasabi for two

years--
years--

well, they were showing physical manifestations of depression
well, they were showing physical manifestations of depression

in response to uncontrollable, stressful events, a condition
in response to uncontrollable, stressful events, a condition

called learned helplessness.
called learned helplessness.

I'm a monster.
I'm a monster.

So let's look at this a little closer.
So let's look at this a little closer.

In the experiment, researchers stressed out these flies
In the experiment, researchers stressed out these flies

by heating them up.
by heating them up.

My lab did that, too.
My lab did that, too.

Some flies could walk around freely and they were OK.
Some flies could walk around freely and they were OK.

But other flies, whose motion was restricted,
But other flies, whose motion was restricted,

could not control their heat exposure
could not control their heat exposure

and ended up just giving up.
and ended up just giving up.

They started walking really slowly
They started walking really slowly

and taking really long breaks and just kind of stopping
and taking really long breaks and just kind of stopping

and giving up.
and giving up.

I imagine that if they could have,
I imagine that if they could have,

they would have shrugged their little melanogaster shoulders
they would have shrugged their little melanogaster shoulders

and just sighed.
and just sighed.

Researchers also noted that female flies
Researchers also noted that female flies

showed more of these depressed behaviors than male flies.
showed more of these depressed behaviors than male flies.

Martin Heisenberg, lead researcher,
Martin Heisenberg, lead researcher,

responded to this finding by saying,
responded to this finding by saying,

"If we realized that the fly trapped in a strange, dark box,
"If we realized that the fly trapped in a strange, dark box,

unable to get rid of the dangerous heat pulses,
unable to get rid of the dangerous heat pulses,

has to find a compromise between saving energy and not missing
has to find a compromise between saving energy and not missing

any chance of escape, we can understand
any chance of escape, we can understand

that such a compromise may come out differently
that such a compromise may come out differently

from males and females, as their resources and goals in life
from males and females, as their resources and goals in life

are different."
are different."

Now, this kind of behavior, this learned helplessness,
Now, this kind of behavior, this learned helplessness,

is not exclusive to fruit flies.
is not exclusive to fruit flies.

And PopSci pointed out that there
And PopSci pointed out that there

was another paper that came up this year that looked
was another paper that came up this year that looked

at harassed, depressed rats.
at harassed, depressed rats.

Now, sometimes, this kind of distress
Now, sometimes, this kind of distress

is induced in mice and rats using a forced swim test.
is induced in mice and rats using a forced swim test.

You take a mouse and you put it into a cylinder of water,
You take a mouse and you put it into a cylinder of water,

and it will start to swim.
and it will start to swim.

But if you leave it there long enough, after a while
But if you leave it there long enough, after a while

it realizes that there's no way to escape
it realizes that there's no way to escape

and it just gives up and stops swimming.
and it just gives up and stops swimming.

You can, after a period of time, reintroduce the mouse to water,
You can, after a period of time, reintroduce the mouse to water,

and once again time the amount of time
and once again time the amount of time

that it takes for it to give up.
that it takes for it to give up.

Now, this amount of time-- it can be modulated
Now, this amount of time-- it can be modulated

using antidepressant drugs.
using antidepressant drugs.

Because of this, the forced swim test
Because of this, the forced swim test

has sometimes been used to test the effectiveness
has sometimes been used to test the effectiveness

of these antidepressant drugs.
of these antidepressant drugs.

However, there is some controversy
However, there is some controversy

surrounding how good of a test it is,
surrounding how good of a test it is,

as some people argue that possibly the mice have learned
as some people argue that possibly the mice have learned

that they're not going to get out of the water
that they're not going to get out of the water

and so what they're doing is conserving energy and waiting
and so what they're doing is conserving energy and waiting

for the researcher to remove them.
for the researcher to remove them.

I will throw in one completely unscientific side note here
I will throw in one completely unscientific side note here

that I do recall watching some of these
that I do recall watching some of these

forced swim test videos in a class at one point in time.
forced swim test videos in a class at one point in time.

And it was nearly impossible not to anthropomorphize those mice
And it was nearly impossible not to anthropomorphize those mice

as just having given up.
as just having given up.

But back to the study at hand.
But back to the study at hand.

In February, some scientists published a new model
In February, some scientists published a new model

for looking at depression in rats.
for looking at depression in rats.

They created a robotic rat which had three settings, chasing,
They created a robotic rat which had three settings, chasing,

which was designed to stress out the rats,
which was designed to stress out the rats,

and continuous and intermittent attack,
and continuous and intermittent attack,

which were designed to induce pain and fear.
which were designed to induce pain and fear.

They set the robots to continuous attack
They set the robots to continuous attack

and allowed them to harass young rats once a day for five days.
and allowed them to harass young rats once a day for five days.

After those young rats had matured,
After those young rats had matured,

they were once again harassed by these robots,
they were once again harassed by these robots,

this time in either continuous or intermittent attacks.
this time in either continuous or intermittent attacks.

They found that the rats who were continuously harassed
They found that the rats who were continuously harassed

in their youth, and then subjected
in their youth, and then subjected

to intermittent attacks when they moved as adults,
to intermittent attacks when they moved as adults,

showed the greatest signs of depression.
showed the greatest signs of depression.

Now, this sounds awful that scientists have harassed rats
Now, this sounds awful that scientists have harassed rats

into depression, but it means that we
into depression, but it means that we

have a potential new model population of rats, which
have a potential new model population of rats, which

are mammals like us, on which we can
are mammals like us, on which we can

test the effects of antidepressant drugs.
test the effects of antidepressant drugs.

And we got that population of depressed rats
And we got that population of depressed rats

without having to do any sort of genetic modification, which
without having to do any sort of genetic modification, which

could have other effects on the rats.
could have other effects on the rats.

And while they still have to test
And while they still have to test

to see just how close this model is
to see just how close this model is

to a model for human depression, it, to me,
to a model for human depression, it, to me,

sounds like a lot more plausible way
sounds like a lot more plausible way

that a human could develop depression
that a human could develop depression

than a forced swim test.
than a forced swim test.

Of course, flies and rats aren't the only animals in which
Of course, flies and rats aren't the only animals in which

we find these behaviors.
we find these behaviors.

They can be found in many different areas
They can be found in many different areas

in the animal kingdom, including in humans.
in the animal kingdom, including in humans.

And so while this may sound like a pretty depressing topic, what
And so while this may sound like a pretty depressing topic, what

it means is that we potentially have some new model organisms
it means is that we potentially have some new model organisms

in flies and rats in which we can study depression
in flies and rats in which we can study depression

and antidepressant drugs.
and antidepressant drugs.

And so I think that that's a topic that might actually hold
And so I think that that's a topic that might actually hold

some hope for a lot of people.
some hope for a lot of people.

Go forth, do science.
Go forth, do science.