Hey there Brainiacs!
Welcome back to Neuro Transmissions.
And hey there, Inés.
Hi Alie!
I have a question for you.
Why do neuroscientists study the brain?
Well, I think that there are a lot of reasons.
They want to better understand how our senses work and find treatments and cures for different
diseases and disorders.
But I think a lot of neuroscientists really just want to understand what makes ou human
brains unique.
Our brain is pretty unique.
But what about the brains of other animals?
Oh sure, we study those too.
Monkeys, rats, mice, birds, fish...
...Bugs?
You would ask that.
See, in addition to being an amazing YouTuber, Ines is an entomologist.
She studies the mechanics of how flies...well, fly!
Yep!
My research focuses on how three species of fly fly, and whether they do so similarly
or differently.
So even though I study the brain and Inés studies insects, you might be surprised to
learn that there is plenty of overlap between those two.
Because bugs DO have brains.
And in fact, lots of neuroscientists are studying insect brains, because their brains are pretty
cool!
Now of course, I knew that already, I just wanted to hear you say it.
Insect brains are so cool.
They’re way smaller than ours, and kinda less complicated, containing about a million
neurons or fewer.
For context, remember that the human brain has about 100 billion neurons.
That’s a hundred thousand times as many.
In fact, unlike human brains, which have to be folded up to fit inside our skulls, insect
brains are more of a sort of simple ladder shape.
They’re made up of six ganglia, or clusters of neuronal cell bodies.
The first pair, called the protocerebrum, mostly controls vision, while the next pair,
the deutocerebrum, processes information coming from the antennae.
Finally, the tritocerebrum controls the labrum, or mouth parts, and helps process information
coming from the other parts of the brain.
It also connects the brain to the ventral nerve cord.
Basically an insect’s spinal cord, except they don’t have a spine, because they have
an exoskeleton.
And the stomodaeal nervous system, which controls the insect’s internal organs.
Because even insects have to know when they’re hungry or in danger.
These six ganglia make up the brain, but there are other ganglia throughout the insect body,
controlling lots of different functions, like movement and digestion.
This is because in insects, the nervous system is sort of...scattered around.
So the control of behavior isn’t so centralized like it is in humans.
The brain can control some things, but lots of things like eating, moving, and mating,
are controlled by the other ganglia.
And so an insect, unlike a human, can survive for quite a long time without a head.
For example, cockroaches can live for weeks after decapitation.
But aside from being kind of cool and kind of freaky, that doesn’t sound very helpful
for understanding how our brains work, does it?
Well, you might be surprised.
Some insects are actually very important models in neuroscience.
And one insect in particular.
The friendly, unassuming fruit fly, drosophila melanogaster.
Hey, I know those!
I actually study them.
Fruit flies are those very tiny, annoying brown bugs you might find in your kitchen
if you’ve left out your bananas for too long.
They’re very popular in research because they’re easy to breed and raise in the lab
and we’ve got lots of genetic tools to help us manipulate their DNA.
And, we share about 60% of the same genes.
Fruit flies only have about 130,000 neurons.
Which is...still a lot, but a lot less to deal with than you’d find in a mammalian
brain.
Their brains are actually really unique.
See, in human brains, we’ve got gray matter, where most of the cell bodies hang out, and
white matter, which are big tracks of axons that send signals from brain region to brain
region.
And in our brains, the grey matter and white matter are sort of grouped in different areas,
and kind of wrap around each other.
But in the fruit fly brain, all of the cell bodies, the gray matter, is grouped on the
outside of the brain.
And all of those axons and dendrites fill up the middle of the brain, sending signals
back and forth.
And unlike in humans, where scientists think about half of the brain is made up of glia,
fruit fly brains are only about 10% glia.
And form a sort of sheet over the outside of the brain.
Scientists are working on creating a full fruit fly connectome right now.
That means they’re trying to map every single cell and every single synapse in the fruit
fly brain.
Mapping the whole fruit fly brain will make it easier for scientists to figure out how
individual cells and circuits play roles in different kinds of behaviors, which can help
us understand at a smaller level how similar cells and circuits might play a role in our
own behavior.
Lots of labs have been discovering really fascinating things using fruit fly brains.
In fact, the 2017 Nobel Prize in Physiology or Medicine went to Drs. Jeffrey Hall, Michael
Robash, and Michael Young for their study of how genes affect circadian rhythms in fruit
flies.
They figured out how a couple of genes change their expression over a 24 hour period.
A sort of cellular clockwork that keeps animals moving on a regular daily cycle.
That’s so cool!
And I’ve heard that scientists continue to discover really interesting things studying
fly brains, using all kinds of amazing techniques, like optogenetics, which lets them turn different
kinds of neurons on and off.
By changing which cells are signaling when, they can influence how the fly behaves under
different conditions, which can tell us something about how the circuits in the brain play different
roles in behavior.
So next time you start swatting those fruit flies in your kitchen, think twice.
You might be destroying someone’s PhD project.
Oh no, we don't want that!
Inés, thank you so much for joining us today!
Thank you so much for having me on!
Head over to Inés’ channel Draw Curiosity, where you can find all kinds of science videos
to stimulate your curiosity.
And now that we’ve talked about the insect brain, you can check out our other collaboration
video on her channel to tackle the next big bug question:
Do insects feel pain?
Thanks for watching this episode of Neuro Transmissions.
Until our next transmission, I’m Alie Astrocyte.
Over and out!