Physicists and bioengineers have developed an optical instrument allowing them to control the behavior of a worm just by shining a tightly focused beam of light at individual neurons inside the organism.
The pioneering optogenetic research, by a team at Harvard University, the University of Pennsylvania, and the University of Massachusetts Medical School, is described this week in the journal Nature Methods. Their device is known as the CoLBeRT (Controlling Locomotion and Behavior in Real Time) system for optical control of freely moving animals, in this case the millimeter-long worm Caenorhabditis elegans.
"This optical instrument allows us to commandeer the nervous system of swimming or crawling nematodes using pulses of blue and green light -- no wires, no electrodes," says Aravinthan D.T. Samuel, a professor of physics and affiliate of Harvard's Center for Brain Science. "We can activate or inactivate individual neurons or muscle cells, essentially turning the worm into a virtual biorobot."
Samuel and colleagues chose to work with C. elegans, an organism often used in biological research, because of its optical transparency, its well-defined nervous system of exactly 302 neurons, and its ease of manipulation. They genetically modified the worms so their neurons express the light-activated proteins channelrhodopsin-2 and halorhodopsin.
In conjunction with high-precision micromirrors that can direct laser light to individual cells, the scientists were then able to stimulate -- using blue light -- or inhibit -- using green light -- behaviors such as locomotion and egg-laying.
"If you shine blue light at a particular neuron near the front end of the worm, it perceives that as being touched and will back away," says co-author Andrew M. Leifer, a Ph.D. student in Harvard's Department of Physics and Center for Brain Science. "Similarly, blue light shined at the tail end of the modified worm will prompt it to move forward."
The scientists were also able to use pulses of light to steer the worms left or right. By stimulating neurons associated with the worm's reproductive system, they were even able to rouse the animal into secreting an egg.
Key to the CoLBeRT system is a tracking microscope recording the motion of a swimming or crawling worm, paired with image processing software that can quickly estimate the location of individual neurons and instruct a digital micromirror device to illuminate targeted cells. Because cells in an unrestrained worm represent a rapidly moving target, the system can capture 50 frames per second and attain spatial resolution of just 30 microns.
"This development should have profound consequences in systems neuroscience as a new tool to probe nervous system activity and behavior, as well as in bioengineering and biorobotics," Samuel says. "Our laboratory has been pioneering new optical methods to study the nervous system, and this is the latest, and perhaps our greatest, invention."
Leifer and Samuel's co-authors on the Nature Methods paper are Christopher Fang-Yen of the University of Pennsylvania, Marc Gershow of Harvard, and Mark J. Alkema of the University of Massachusetts Medical School. Their work was supported by the Dana Foundation, the National Science Foundation, and the National Institutes of Health.
Steve Bradt | EurekAlert!
Researchers at Fraunhofer monitor re-entry of Chinese space station Tiangong-1
21.03.2018 | Fraunhofer-Institut für Hochfrequenzphysik und Radartechnik FHR
Taming chaos: Calculating probability in complex systems
21.03.2018 | American Institute of Physics
An international team of researchers has discovered a new anti-cancer protein. The protein, called LHPP, prevents the uncontrolled proliferation of cancer cells in the liver. The researchers led by Prof. Michael N. Hall from the Biozentrum, University of Basel, report in “Nature” that LHPP can also serve as a biomarker for the diagnosis and prognosis of liver cancer.
The incidence of liver cancer, also known as hepatocellular carcinoma, is steadily increasing. In the last twenty years, the number of cases has almost doubled...
In just a few weeks from now, the Chinese space station Tiangong-1 will re-enter the Earth's atmosphere where it will to a large extent burn up. It is possible that some debris will reach the Earth's surface. Tiangong-1 is orbiting the Earth uncontrolled at a speed of approx. 29,000 km/h.Currently the prognosis relating to the time of impact currently lies within a window of several days. The scientists at Fraunhofer FHR have already been monitoring Tiangong-1 for a number of weeks with their TIRA system, one of the most powerful space observation radars in the world, with a view to supporting the German Space Situational Awareness Center and the ESA with their re-entry forecasts.
Following the loss of radio contact with Tiangong-1 in 2016 and due to the low orbital height, it is now inevitable that the Chinese space station will...
Fraunhofer Institute for Organic Electronics, Electron Beam and Plasma Technology FEP, provider of research and development services for OLED lighting solutions, announces the founding of the “OLED Licht Forum” and presents latest OLED design and lighting solutions during light+building, from March 18th – 23rd, 2018 in Frankfurt a.M./Germany, at booth no. F91 in Hall 4.0.
They are united in their passion for OLED (organic light emitting diodes) lighting with all of its unique facets and application possibilities. Thus experts in...
A new scenario seeking to explain how Mars' putative oceans came and went over the last 4 billion years implies that the oceans formed several hundred million...
For the first time, an interdisciplinary team from the University of Basel has succeeded in integrating artificial organelles into the cells of live zebrafish embryos. This innovative approach using artificial organelles as cellular implants offers new potential in treating a range of diseases, as the authors report in an article published in Nature Communications.
In the cells of higher organisms, organelles such as the nucleus or mitochondria perform a range of complex functions necessary for life. In the networks of...
19.03.2018 | Event News
16.03.2018 | Event News
13.03.2018 | Event News
22.03.2018 | Trade Fair News
22.03.2018 | Earth Sciences
22.03.2018 | Earth Sciences