Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Penn Researcher Helps Identify “Superfast” Muscles Responsible for Bat Echolocation

As nocturnal animals, bats rely echolocation to navigate and hunt prey.

By bouncing sound waves off objects, including the bugs that are their main diet, bats can produce an accurate representation of their environment in total darkness. Now, researchers at the University of Southern Denmark and the University of Pennsylvania have shown that this amazing ability is enabled by a physical trait never before seen in mammals: so-called “superfast” muscles.

The work was conducted by Coen Elemans, John Ratcliffe and Lasse Jakobsen of Denmark, along with Andrew Mead, a graduate student in the Department of Biology in Penn’s School of Arts and Science.

Their findings will appear in the journal Science.

Superfast muscles are capable of contraction about 100 times faster than typical body muscles and as much as 20 times faster than the fastest human muscles, those that control eye movement. Mead, who studies muscle physiology, and Elemans, who studies neuroscience and biomechanics, had previously collaborated in studying how superfast muscles help birds sing.

“Superfast muscles were previously known only from the sound-producing organs of rattlesnakes, birds and several fish,” Elemans said. “Now we have discovered them in mammals for the first time, suggesting that these muscles – once thought extraordinary – are more common than previously believed.”

With vision, animals receive a more-or-less continuous stream of information about the world. With echolocation, however, bats only get a snapshot of their environment with each call and echo, requiring them to make rapid successions of calls. When hunting a flying insect that can quickly move in any direction, bats need the most rapid updates on their prey’s position in the instant before the catch. At this critical point, bats produce what is known as the “terminal buzz,” where they make as many as 190 calls per second.

“Bat researchers assumed that the muscles that control this behavior must be pretty fast, but there was no understanding of how they worked,” Mead said. “Research on superfast muscles is just a world apart from what they do. This study represents many worlds coming together: the muscle world, that bio-acoustics and echolocation world and the bat behavioral world.”

The researchers tested the performance of the bats’ vocal muscles by attaching one between a motor and a force sensor and electrically stimulating it to flex. When the motor was stationary, a single electric pulse allowed the researchers to measure the time that bat muscle took to twitch, or to contract and relax.

“The twitch gives us a sense of the time it takes for a muscle cell to go though all the steps, all the chemical reactions, necessary exert force and to relax again,” Mead said. “The faster the muscle, the shorter the twitch. These muscles could go through all the motions in less than a hundredth of a second.”

To approximate how much work the muscle was doing within the bat, however, the researchers had to change the length of the muscle while it was contracting. When the motor was on, it lengthened and shortened the muscle at a controllable rate. While the muscle was being stretched, the researchers stimulated the muscle to contract, so they could see if the muscle pulled on the motor harder than the motor pulled on the muscle.

The test to see if the muscle was truly of the superfast type involved increasing the speed of the motor to more than a 100 oscillations per second.

“You're always limited to how many twitches you can do in a given period of time,” Mead said. “If you keep on increasing the frequency, doing twitch after twitch, you get to the point where the twitches begin to build on top of each other and the muscle doesn’t fully turn off. We went to the highest cycling frequency where we still had evidence that the muscle was turning on and off. ”

The researchers also did an experiment in which bats hunted insects in a chamber wired with microphones in order to determine the theoretical maximum frequency for a buzz without overlapping echoes, which could confuse the bat.

“We determined the power the muscles can deliver, much like how you measure a car’s performance,” Denmark’s Elemans said. “We were surprised to see that bats have the superfast muscle type and can power movements up to 190 times per second, but also that it is actually the muscles that limit the maximum call rate during the buzz.”

“You can think of it like a car engine,” Mead said. “It can be tuned to be efficient, or tuned to be powerful depending on what you want it to do. It turns out that bats trade off a lot of force to be able to get these rapid oscillations. In a way it’s like an engine that’s been tuned for extremely high RPM.”

Mead and Elemans plan further study of superfast muscles from a molecular and genetic perspective.

“With more and more genomes being sequenced, including one species of bat, and one from a bird we’ve studied,’ Mead said, “we have some powerful tools to start pick apart whether or not similar genes are involved in various important roles.”

The work was supported by the Danish Research Council, Carlsberg Foundation, Grass Foundation, Company of Biologists and Oticon Foundation.

Evan Lerner | EurekAlert!
Further information:

Further reports about: Foundation chemical reaction echolocation muscles sound wave

More articles from Life Sciences:

nachricht Novel mechanisms of action discovered for the skin cancer medication Imiquimod
21.10.2016 | Technische Universität München

nachricht Second research flight into zero gravity
21.10.2016 | Universität Zürich

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: New 3-D wiring technique brings scalable quantum computers closer to reality

Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.

"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...

Im Focus: Scientists develop a semiconductor nanocomposite material that moves in response to light

In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.

A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...

Im Focus: Diamonds aren't forever: Sandia, Harvard team create first quantum computer bridge

By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.

"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...

Im Focus: New Products - Highlights of COMPAMED 2016

COMPAMED has become the leading international marketplace for suppliers of medical manufacturing. The trade fair, which takes place every November and is co-located to MEDICA in Dusseldorf, has been steadily growing over the past years and shows that medical technology remains a rapidly growing market.

In 2016, the joint pavilion by the IVAM Microtechnology Network, the Product Market “High-tech for Medical Devices”, will be located in Hall 8a again and will...

Im Focus: Ultra-thin ferroelectric material for next-generation electronics

'Ferroelectric' materials can switch between different states of electrical polarization in response to an external electric field. This flexibility means they show promise for many applications, for example in electronic devices and computer memory. Current ferroelectric materials are highly valued for their thermal and chemical stability and rapid electro-mechanical responses, but creating a material that is scalable down to the tiny sizes needed for technologies like silicon-based semiconductors (Si-based CMOS) has proven challenging.

Now, Hiroshi Funakubo and co-workers at the Tokyo Institute of Technology, in collaboration with researchers across Japan, have conducted experiments to...

All Focus news of the innovation-report >>>



Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

Agricultural Trade Developments and Potentials in Central Asia and the South Caucasus

14.10.2016 | Event News

World Health Summit – Day Three: A Call to Action

12.10.2016 | Event News

Latest News

Resolving the mystery of preeclampsia

21.10.2016 | Health and Medicine

Stanford researchers create new special-purpose computer that may someday save us billions

21.10.2016 | Information Technology

From ancient fossils to future cars

21.10.2016 | Materials Sciences

More VideoLinks >>>