Understanding the neurological code behind how flies fly

October 12, 2018, Case Western Reserve University
Understanding the neurological code behind how flies fly
Alexandra Yarger Credit: Case Western Reserve University

A common flesh fly takes off and maneuvers effortlessly, its head and body steadied by a hidden, miniscule gyroscope-like structure that gives it an unparalleled balance.

That same fly—those specialized structures, known as "halteres," now surgically removed—takes off again, but immediately begins to tumble wildly about, unable to right herself or tell up from down, side from side.

So what's happening? Why does it matter? And what might it mean for us?

Case Western Reserve University's Alexandra Yarger, a Ph.D. candidate in biology and first author on a new paper published in September in the journal Proceedings of the Royal Society B, has some of the answers to those questions.

Yarger studies the electrical activity of neurons in the haltere structure, which was once a second set of wings, but transformed by millions of years of evolution into what serves as the unseen balancing system.

Her discoveries might someday help us build more responsive drones or better-balanced robots, said Jessica Fox, assistant professor of biology at Case Western Reserve and Yarger's mentor on the project. Her lab has been studying the behavior of flies and how sensory systems process information since 2013.

"We had already demonstrated in a 2015 paper what flies actually do with their halteres when moving around and in this paper, we've asked what their nervous systems do with that information," she said.

Flies possess specialized sensory organs called halteres that help them detect body rotations during flight. With their halteres removed, they can no longer maintain stability. Credit: Alexandra Yarger, Case Western Reserve University
Advancing the long history of fly science

Yarger gained much of her insight by essentially taking over the operation of the haltere for several species of common flies: flesh flies, black flies and hoverflies. She glued a bit of metal to the tip of each fly's haltere and then manipulated it with a small magnet to simulate a change in orientation during flight and then recorded the electrical signals it generated—essentially a code sent "downstream" to the muscles make the fly a better flier than other insects.

"We know that the halteres activate the neurons, which in turn, tell their wings and neck what to do—but no one really knew exactly how that happened until now," said Yarger, who worked on the project over a period of about two years, beginning in 2016.

Scientists had first shown the effect of haltere removal as far back as 1714, Fox said.

And the idea that that when the fly was rotating, neurons might respond differently than when the fly was not rotating had been postulated 70 years ago by a scientist named J.W. Pringle, but he was never able to test his hypotheses directly for lack of technology to do the job.

But Pringle did have two related thoughts—that either some neurons that didn't fire when the fly was straight would start firing when the fly rotated; or that some neurons might change the timing of when they fire when the fly rotates, Fox said.

"Alex found that both of these ideas were correct and now we have a clear idea of what the code is because she found it," Fox said. "We found that this single spike moving around in time is what forms the code of 'I'm rotating' vs. 'I'm not rotating.'

"Next, we want to know how the downstream integrate inputs from these 300 cells to produce an appropriate behavioral output."

Explore further: Halteres, essential for flight in all flies, are needed by some to climb walls (w/ video)

More information: Alexandra M. Yarger et al, Single mechanosensory neurons encode lateral displacements using precise spike timing and thresholds, Proceedings of the Royal Society B: Biological Sciences (2018). DOI: 10.1098/rspb.2018.1759

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FredJose
1 / 5 (3) Oct 12, 2018
which was once a second set of wings, but transformed by millions of years of evolution into what serves as the unseen balancing system.

Oh, PLEASE MAN, spare us this kind of non-science!!!!!!!
Here you have an absolutely amazing balancing system that out performs anything mankind has created till now, set in a minute structure that defies belief and she goes off on a loose limb to declare the wonderful abilities of the evolutionary god to design such things.

So I am very happy for their discovery but must take the time to highlight this item:
have a clear idea of what the code is because she found it,


They clearly see that code is involved. Which means that somewhere decoding has to occur. Which means that some intelligence was involved in creating the meaning between the coding and decoding phases. There is no other explanation for how an ABSTRACT entity can arise via purely random materialistic processes. Get real.
Ojorf
3.5 / 5 (2) Oct 12, 2018
Your definition of non-science is wrong, Fred.
... and your thoughts on coding and decoding too.
FredJose
1 / 5 (2) Oct 13, 2018
@Ojorf: I suppose you can show how they applied the scientific method to extricate the knowledge of "millions of years of evolution" , right?
If not, then their statement is simply a homage to the evolutionary god. Pure none-science.

As for coding and decoding - these mechanisms have an underlying meaning attached to them, so your statement is simply vacuous unless of course you'd like to expound on how my thoughts are wrong. It would be instructive to see how you get abstract entities from purely materialistic processes. That is something I'd like to behold.
FredJose
1 / 5 (2) Oct 13, 2018
which was once a second set of wings, but transformed by millions of years of evolution into what serves as the unseen balancing system.

So how did it fly in the meantime? How did it manage to survive for those millions of years without the ability to fly?
rrwillsj
not rated yet Oct 13, 2018
Well freddyboy, you do have an interesting question there.
"... So how did it fly in the meantime? How did it manage to survive for those millions of years without the ability to fly?..."

I would imagine it was by the same method your caretakers use, holding your hand firmly to cross a street. Do that over a few hundred milliom years and maybe even you could learn how to safely cross a busy intersection without assistance?
torbjorn_b_g_larsson
not rated yet Oct 14, 2018
spare us this kind of non-science

Ridiculous. Look where you are writing, this is a science site and that is an article on peer reviewed science. Besides, it is basic biology. Besides, you instead try to insert irrelevancies such as religion.

somewhere decoding has to occur.

The neuronal code is decoded in the fly brain obviously. (Though it looks like you think it was about genetic sequences based on their triplet code for amino acids.)

Did you even read the article?

So how did it fly in the meantime?

Why this trivial question? "It" did not fly, but its ancestors flew, since this lineage did not loose flight. The rest is in the article and paper.
torbjorn_b_g_larsson
not rated yet Oct 14, 2018
kind of non-science

Ridiculous. Look where you are writing, this is a science site and that is an article on peer reviewed science. Besides, it is basic biology. Besides, you instead try to insert irrelevancies such as religion.

somewhere decoding has to occur.

The neuronal code is decoded in the fly brain obviously, for which it was "coded" (signaled) in the first place.

Did you even read the article?

So how did it fly in the meantime?

Why this trivial question? "It" did not fly then, this is an evolved trait, but its ancestors flew (and remotely enough they flew differently, hence the evolutionary change from two wing pairs to 1 pair + halteres derived from the modified pair), since this lineage did not loose flight. The rest is in the article and paper.

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