 |
|
'Electric' fish shed light on ways the brain directs movement
February 01, 2007Scientists have long struggled to figure out how the brain guides the complex movement of our limbs, from the graceful leaps of ballerinas to the simple everyday act of picking up a cup of coffee. Using tools from robotics and neuroscience, two Johns Hopkins University researchers have found some tantalizing clues in an unlikely mode of motion: the undulations of tropical fish.
Their findings, published in the January 31 issue of the Journal of Neuroscience, shed new light on the communication that takes place between the brain and body. The fish research may contribute to important medical advances in humans, including better prosthetic limbs and improved rehabilitative techniques for people suffering from strokes, cerebral palsy and other debilitating conditions.
"All animals, including humans, must continually make adjustments as they walk, run, fly or swim through the environment. These adjustments are based on feedback from thousands of sense organs all over the body, providing vision, touch, hearing and so on. Understanding how the brain processes this overwhelming amount of information is crucial if we want to help people overcome pathologies," said Noah Cowan, an assistant professor of mechanical engineering in Johns Hopkins' Whiting School of Engineering. In studying the fish and preparing the Neuroscience paper, Cowan teamed up with Eric Fortune, assistant professor of psychological and brain sciences in the Krieger School of Arts and Sciences, also at Johns Hopkins.
Cowan and Fortune focused on the movements of a small, nocturnal South American fish called the "glass knifefish" because of its almost transparent, blade-shaped body. This type of fish does something remarkable: it emits weak electrical signals which it uses to "see" in the dark. According to Fortune, several characteristics, including this electric sense, make this fish a superb subject for the study of how the brain uses sensory information to control locomotion.
"These fish are ideal both because we can easily monitor the sensing signals that their brains use and because the task we asked the fish to do — swim forward and backward inside a small tube — is very simple and straightforward," said Fortune, who also uses the fish to study the neural basis and evolution of behavior.
The fish prefer to "hide" inside these tubes, which are immersed in larger water tanks. In their research, Cowan and Fortune challenged the fish's ability to remain hidden by shifting the tubes forward and backward at varying frequencies. This required the fish to swim back and forth more and more rapidly in order to remain inside the tubes. But as the frequency became higher, the fish gradually failed to keep up with the movement of the tubes.
The team's detailed engineering analysis of the fish's adjustments under these conditions suggested that the animal's sensors and brains are "tuned" to consider Newton's laws of motion, Cowan said. In other words, the team found that the fish's nervous systems measured velocity, so the fish could accelerate or "brake" at just the right rate to remain within the moving tube.
"The fish were able to accelerate, brake and reverse direction based on a cascade of adjustments made through their sensory and nervous systems, in the same way that a driver approaching a red light knows he has to apply the brakes ahead of time to avoid overshooting and ending up in the middle of a busy intersection," Fortune said. "Your brain has to do this all the time when controlling movement because your body and limbs, like a car, have mass. This is true for large motions that require planning, such as driving a car, but also for unconscious control of all movements, such as reaching for a cup of coffee. Without this sort of predictive control, your hand would knock the cup off the table every time."
"That animals unconsciously know that they have mass seems obvious enough, but it took a complex analysis of a very specialized fish to demonstrate this," Fortune said. "With this basic knowledge, we hope one day to be able to 'tune' artificial systems, such as prosthetics, so that they don't have the jerky and rough movements that most robots have, which is critical for medical applications."
The team's use of both neuroscience and engineering principles and tools also make it an important project for other reasons.
"So far, we have used a series of engineering analyses to tease apart some important information about how the nervous system works," Cowan said. "As we move forward, we expect to discover other exciting aspects of brain function that suggest new ways to design sensory control systems for autonomous robots."
Johns Hopkins University
Cowan and Fortune focused on the movements of a small, nocturnal South American fish called the "glass knifefish" because of its almost transparent, blade-shaped body. This type of fish does something remarkable: it emits weak electrical signals which it uses to "see" in the dark. According to Fortune, several characteristics, including this electric sense, make this fish a superb subject for the study of how the brain uses sensory information to control locomotion.
"These fish are ideal both because we can easily monitor the sensing signals that their brains use and because the task we asked the fish to do — swim forward and backward inside a small tube — is very simple and straightforward," said Fortune, who also uses the fish to study the neural basis and evolution of behavior.
The fish prefer to "hide" inside these tubes, which are immersed in larger water tanks. In their research, Cowan and Fortune challenged the fish's ability to remain hidden by shifting the tubes forward and backward at varying frequencies. This required the fish to swim back and forth more and more rapidly in order to remain inside the tubes. But as the frequency became higher, the fish gradually failed to keep up with the movement of the tubes.
The team's detailed engineering analysis of the fish's adjustments under these conditions suggested that the animal's sensors and brains are "tuned" to consider Newton's laws of motion, Cowan said. In other words, the team found that the fish's nervous systems measured velocity, so the fish could accelerate or "brake" at just the right rate to remain within the moving tube.
"The fish were able to accelerate, brake and reverse direction based on a cascade of adjustments made through their sensory and nervous systems, in the same way that a driver approaching a red light knows he has to apply the brakes ahead of time to avoid overshooting and ending up in the middle of a busy intersection," Fortune said. "Your brain has to do this all the time when controlling movement because your body and limbs, like a car, have mass. This is true for large motions that require planning, such as driving a car, but also for unconscious control of all movements, such as reaching for a cup of coffee. Without this sort of predictive control, your hand would knock the cup off the table every time."
"That animals unconsciously know that they have mass seems obvious enough, but it took a complex analysis of a very specialized fish to demonstrate this," Fortune said. "With this basic knowledge, we hope one day to be able to 'tune' artificial systems, such as prosthetics, so that they don't have the jerky and rough movements that most robots have, which is critical for medical applications."
The team's use of both neuroscience and engineering principles and tools also make it an important project for other reasons.
"So far, we have used a series of engineering analyses to tease apart some important information about how the nervous system works," Cowan said. "As we move forward, we expect to discover other exciting aspects of brain function that suggest new ways to design sensory control systems for autonomous robots."
Johns Hopkins University
Movement Current Events and Movement News RSSStroke and heart disease trigger revealed in new research
Scientists have identified the trigger that leads to the arteries becoming damaged in the disease atherosclerosis, which causes heart attacks and strokes, in research published today in the journal Circulation.
Study shows dream-enacting behavior is common in healthy young adults
A study in the Dec.1 issue of the journal Sleep shows that dream-enacting behaviors are common in healthy young adults, and the prevalence of specific behaviors differs between men and women.
Study shows that adults have dreamlike thoughts during sleepwalking and sleep terrors episodes
A study in the Dec.1 issue of the journal Sleep shows that short, unpleasant, dreamlike mental activity occurs during sleepwalking and sleep terrors episodes, suggesting that people with these sleep disorders may be acting out dreamlike thoughts.
Caltech scientists find emotion-like behaviors, regulated by dopamine, in fruit flies
Scientists at the California Institute of Technology (Caltech) have uncovered evidence of a primitive emotion-like behavior in the fruit fly, Drosophila melanogaster.
Caltech scientists explain puzzling lake asymmetry on Titan
Researchers at the California Institute of Technology (Caltech) suggest that the eccentricity of Saturn's orbit around the sun may be responsible for the unusually uneven distribution of lakes over the northern and southern polar regions of the planet's largest moon, Titan.
Galician waves are best for producing energy
The best coastal areas in the Iberian Peninsula in terms of harnessing wave energy are the Costa da Morte and Estaca de Bares, in La Coruña, Galicia, according to two pioneering studies by researchers from the University of Santiago de Compostela (USC), published this month in the journals Energy and Renewable Energy.
Fish food fight: Fish don't eat trees after all, says new study
What constitutes fish food is a matter of debate. A high-profile study a few years ago suggested that fish get almost 50 percent of their carbon from trees and leaves, evidence for a very close link between the terrestrial and aquatic ecosystems.
New study finds MRSA on the rise in hospital outpatients
The community-associated strain of the deadly superbug MRSA-an infection-causing bacteria resistant to most common antibiotics-poses a far greater health threat than previously known and is making its way into hospitals, according to a study in the December issue of Emerging Infectious Diseases.
New Method to Measure Snow, Soil Moisture With GPS May Benefit Meteorologists, Farmers
A research team led by the University of Colorado at Boulder has found a clever way to use traditional GPS satellite signals to measure snow depth as well as soil and vegetation moisture, a technique expected to benefit meteorologists, water resource managers, climate modelers and farmers.
Nuclear weapons: Predicting the unthinkable
If a nuclear weapon were detonated in a metropolitan area, how large would the affected area be? Where should first responders first go? According to physicist Fernando Grinstein, we have some initial understanding to address these questions, but fundamental issues remain unresolved.
More Movement Current Events and Movement News Articles
 |
Movement (2 CD Collector's Edition) by New Order Digitally remastered and expanded two CD edition of this 1981 album from the Manchester quartet, one of the most successful and consistent bands of the '80s and beyond. After the suicide of vocalist, Ian Curtis, the three surviving members of Joy Division regrouped under the band name New Order, adding Gillian Gilbert on keyboards. The rest, as they say, is history. Disc One in this package contains the original album in its digitally remastered glory. Disc Two is filled with 10 non-album singles, B-sides and remixes. This is as great as it gets! Rhino UK. 2008. |
 |
Movement by New Order This is New Order's debut in name only, with the ghost of Ian Curtis still hanging heavily over his grieving Joy Division bandmates. It would take them one more step, to the brilliant Power, Corruption and Lies, to really assert their own power. Movement, then, is the sound of guitarist Bernard Sumner, percussionist Stephen Morris, and innovative bassist Peter Hook building a bridge from JD's Sturm und Drang drone to New Order's considerably brighter dance pop. It's an interesting bridge to cross though, peppered with dark highlights like the almost poppy "Dreams Never End," the blip-blooping electro chaos of the Pere Ubu-influenced "ICB," and "The Him," with its rhythmic echoes of JD's "Atrocity Exhibition." --Michael Ruby |
![Movement [Collector's Edition]](http://ecx.images-amazon.com/images/I/41JZkGcnIXL._SL160_.jpg) |
Movement [Collector's Edition] New Order (Primary Contributor) |
 |
Guido Mocafico: Movement by Francois-Paul Journe (Author), Stephen Forsey (Author), Antoine Simonin (Author), Patrick Remy (Editor), Guido Mocafico (Editor) Time is naturally marked by repeating astronomical phenomena, by the daily cycle and the seasons, as nights and months come and go. To slice it into finer fractions, our forbears invented sundials, which track the movement of the shadows projected by the sun, or clepsydra, hourglass-like devices that count time based on a consistent rate of water flow. But ever since 1657, when the first watch was created, we have used the oscillatory movements of a mechanical system to do that job. The photographer Guido Mocafico, whose previous books include Venenum, Medusa and Serpens, sets out in this new project, Movement, to observe these systems. He chose complex and rare mechanisms--physically mechanical rather than electronic--which led him into a world of traditional knowledge controlled by... |
 |
Good Morning Exercises for Kids by Various Artists Here's a great way to begin every day. Use these easy and fun movement exercises to motivate your children and get them clapping, skipping, stretching, doing sit-ups and more! The classic songs will help kids to wake up and warm-up. |
 |
The Movement by The Movement |
 |
Anatomy of Movement (Revised Edition) by Blandine Calais-Germain (Author) Anatomy of Movement presents a dynamic, integrated approach to the study of the physical structures of the musculoskeletal system and their functional relationship to the movements of the human body. In clear and concise text illustrated with more than a thousand graphic drawings, the author guides the reader on a lively tour of the muscles, bones, ligaments and joints of the arms, legs and trunk. The focus throughout the book is on anatomy not for its own sake, but in its functional relationship to the actual movements of the body in dance, exercise, and other physical disciplines. In this newly-revised edition, a majority of the thousand-plus illustrations are new or have been modified by the author from the original edition. The text has also been updated, and the sequencing of the... |
 |
Girls On The Dance Floor Far East Movement (Primary Contributor) |
 |
Graco Angelcare Deluxe Movement Sensor With Sound Monitor by Graco Baby tions Rechargeable Charging Bases included 8 Channels |
 |
JAM: Music for Movement with Children Charity Kahn (Performer) JAM: Music for Movement with Children, was born out of Charity Kahn's JAM Sessions -- music and movement classes for little people and their big people. All songs have accompanying movements, and one need only read the track list to get a feel for the kind of creative play and joyful fun these songs will inspire in your kids. Themes range from animals to trains to body-as-instrument to counting to yoga to the infamous Creeper Walk. You and your kids will love to listen and move to these tunes at home, on the road, wherever...again and again and again! Charity's beautiful voice and ingenious harmonies permeate the recording, as do the originality and insightfulness of her songwriting. Instruments include piano, bass, guitar, mandolin, flute and percussion. Appropriate ages: All! For... |
| © 2009 BrightSurf.com |