3D Robotics

Scientists monitor dragonfly brains on the fly


One of the best ways to design micro-UAVs is to emulate insects. But figuring out how insects navigate and fly is hard, unless you can monitor their neurons in action. Scientists have now figured out how to do that. A fascinating piece from my alma mater, Wired:

The brain of a dragonfly has to do some serious calculations — and fast — if it hopes to nab a mosquito or midge in midair. It has to predict the trajectory of its prey, plot a course to intersect it, then make adjustments on the fly to counteract any evasive maneuvers. Neuroscientist Anthony Leonardo created the tiny dragonfly backpack above to study how circuits of neurons do these computations.

The backpack weighs 40 milligrams, about as much as a couple grains of sand, equal to just 10 percent of the dragonfly’s weight. Electrodes inserted into the dragonfly’s body and brain record the electrical activity of neurons, and a custom-made chip amplifies the signals and transmits them wirelessly to a nearby computer.

One of the trickiest design challenges was how to power the chip without adding so much mass that the insects couldn’t get off the ground, says Leonardo, who’s based at Howard Hughes Medical Institute’s Janelia Farm Research Campus in Ashburn, Virginia.

He and collaborators at Duke University and Intan Technologies came up with a clever solution based on the same technology found in the RFID key card access system used in many office buildings. There, a reader, usually a small pad next to a door, emits radio waves to create a magnetic field. When a key card gets close enough to the reader, the magnetic field induces a current that powers a chip inside the card, enabling it to transmit a code to unlock the door.

The two long antennae on the dragonfly backpack harvest radio waves and power the chip in a similar way. Eliminating the need for a battery on the backpack was the key to keeping the weight down.

Dragonfly flight arena. Photo: Anthony Leonardo, Janelia Farm Research Campus / HHMI

Getting dragonflies to hunt inside the lab turned out to be a little tricky too, Leonardo says. In a plain white room, the insects exhaust themselves trying to escape. So the team installed turf on the floor, installed a small pond, and covered the walls with a scene that evokes a springtime meadow.

In their experiments, the researchers release fruit flies and watch the dragonflies take off from a perch and catch them. Eighteen high-speed infrared video cameras positioned around the room capture every move as a dragonfly closes in on its prey and launches its body upwards, curling its hairy legs inward to form a sort of basket trap (see video below).

As the dragonfly hunts, the backpack captures the firing of neurons Leonardo thinks play a crucial role in guiding it towards its prey. “We know a lot about their anatomy,” he said. “They gather input from visual parts of the brain and send axons down to the motor neurons that move the wings.”

The question that fascinates Leonardo is how those neurons and others transform information about the visual scene into a plan of action, and how they continuously update the plan as the dragonfly and its prey move through space. All animals do this type of transformation, from a center fielder running down a fly ball to a lion running down a gazelle. But a neuroscientist can’t exactly study those situations in the lab.

“The dragonfly is a convenient and beautiful and elegant means to an end,” Leonardo said.

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  • HeliStorm, I'm happy to correspond via email.  You can find my main email address on my personal website: TravisDeyle.com

  • Travis, my day job is in the medical field, specifically the management of othopedic surgical instrumentation. We use a passive RFID system to verify the accuracy and validity of inventory for an inputted case. The tunnel scan before heading out the door is the final check, and ensures accuracy. This is really my only exposure to RFID, and I had never given it much thought in applications such as this. I would love to discuss this project further, through other communications means.
  • Admin

    Amazing  nano electronic:)

  • Hey Chris,

    This was actually part of my postdoc work at Duke after leaving Georgia Tech's Healthcare Robotics Lab.  Here's a paper that describes the early system:


    For my postdoc, I worked on gen2 of the backscatter wireless system: wireless power harvesting and high-speed wireless data transfer akin to souped-up, passive UHF RFID tags. Specifically, I helped build the new analog (RF) frontend and high-speed software defined radio (ADCs and FPGA) receiver so that we could decode the neural signals in real-time (5 Mbps datarate on 900MHz carrier) rather than offline in MatLab.

    I'm happy to answer any questions (will check back tomorrow)... but in the meantime, these recent IEEE RFID conference papers give a pretty good overview the architecture and some other applications with different sensor payloads.




    ~Travis Deyle (from Hizook)

  • I wonder if the dragon fly will suffer any ill side effects? I couldn't think that probes in your back and brains would be conducive to good health!

  • Amazing...argh...mobile devices...
  • Wow! This is very anazing.

    A few years ago, I saw something similar with bees, yet the bee was held in place, dangling by a fine wire feeding power if I remember correct. Since the bee really couldn't fly anywhere, they had a bee flight simulator for it to navigate. I am sure this gives better data.

    I have said before, bugs are great little critters to emulate in robotics. Simplicity and complexity rolled into a compact, self propelled, self recharging package.
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