Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Stimulating nerve cells with laser precision

27.10.2004


Researchers devise optical method to safely, effectively stimulate neurons



Biomedical engineers and physicians at Vanderbilt University have brought the day when artificial limbs will be controlled directly by the brain considerably closer by discovering a method that uses laser light, rather than electricity, to stimulate and control nerve cells.

The researchers have discovered that low-intensity infrared laser light can spark specific nerves to life, exciting a leg or even individual toes without actually touching the nerve cells. “This technique brings nerve stimulation out of the Dark Ages,” said Vanderbilt Assistant Professor of Biomedical Engineering and Neurological Surgery Anita Mahadevan-Jansen. “Much work is going on around the world trying to make electric nerve stimulation better, but the technique is inherently limited. Using lasers instead, we can simultaneously excite and record the responses of nerve fibers with much greater precision, accuracy and effectiveness.”


The method was developed by Mahadevan-Jansen; her husband Duco Jansen, associate professor of biomedical engineering and neurological surgery; Dr. Peter Konrad and Dr. Chris Kao of Vanderbilt Neurological Surgery, both assistant professors of neurological surgery; and biomedical engineering doctoral student Jonathon Wells.

In an experiment with rats, the scientists used a laser to stimulate the sciatic nerve and to control muscles in the animal’s hind leg and individual toes, demonstrating accuracy beyond the limitations of electrical stimulation. Immediately following the experiment, the rats regained full use of their legs with no signs of weakness or damage.

Konrad, who is also director of the Vanderbilt Functional Neurosurgery program, points out that neurostimulation is ideally done cell by cell. “The problem with the conventional electrical method is that we have a large zone around our target neuron that also is affected simply because of the way electricity travels throughout the tissue. Using light to stimulate neurons, we can pick off a single neuron without affecting the other neurons around it.”

In a matter of months, Kao says, a machine could be created that helps guide neurosurgeons to the target nerves during rhizotomy, a procedure that frees someone from a spastic or seemingly frozen muscle, as when someone’s head is stuck in a tortuous position. Currently, once the proper neural region is selected, surgeons pinpoint the individual nerves by a process of elimination, striking nerves with an electric probe while the patient is awake to ensure that the right nerve has been located.

But electrical probes create a halo of electrical activity in surrounding neurons, creating a "blind spot" and other inaccurate data in the recording and analysis of the procedure, making it tedious and difficult to locate the exact nerve. Optics, on the other hand, can deliver laser precision by stimulating only the nerve cell of interest.

The idea of optical stimulation started as the scientists questioned whether they could accurately detect the movement through the brain of an electrical impulse from a nerve cell. Konrad suggested using light to trace the activity, and Mahadevan-Jansen thought of using laser light to stimulate nerves and to actually generate this activity.

Vanderbilt’s W.M. Keck Foundation Free Electron Laser Center was the perfect facility to give it a try. The Department of Defense-funded FEL, one of only a handful in the world and the only one equipped to perform medical experimental research, was used to see if the idea worked and to determine the optimal settings for the laser.

Now that the research team has shown that the process works and that it is safe, they are turning their attention to studying the exact mechanisms behind the stimulation effects. The most likely candidates, Jansen and Wells say, include a photothermal or mechanical effect or perhaps a combination of the two.

The scientists are beginning experiments in the central nervous system.

Mahadevan-Jansen said the technique, which is pending patent approval, is not the only novel aspect of this work. "This research results from the marriage of biomedical engineering, optical science and neurological research," Mahadevan-Jansen said. "Some programs are working on optics, and some are working on neurological stimulation, but nobody has put them together."

Imagining future applications, Konrad said he can envision an array of fiber optic threads that runs directly from the brain or spinal cord to a prosthetic arm or leg, creating the ultimate man-machine interface.

Vivian Cooper-Capps | EurekAlert!
Further information:
http://www.vanderbilt.edu

More articles from Life Sciences:

nachricht The balancing act: An enzyme that links endocytosis to membrane recycling
07.12.2016 | National Centre for Biological Sciences

nachricht Transforming plant cells from generalists to specialists
07.12.2016 | Duke University

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Significantly more productivity in USP lasers

In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.

Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...

Im Focus: Shape matters when light meets atom

Mapping the interaction of a single atom with a single photon may inform design of quantum devices

Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

Im Focus: MADMAX: Max Planck Institute for Physics takes up axion research

The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.

The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

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

14.10.2016 | Event News

 
Latest News

NTU scientists build new ultrasound device using 3-D printing technology

07.12.2016 | Health and Medicine

The balancing act: An enzyme that links endocytosis to membrane recycling

07.12.2016 | Life Sciences

How to turn white fat brown

07.12.2016 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>