Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Watching individual neurons respond to magnetic therapy

30.06.2014

New technique could show transcranial magnetic stimulation (TMS) treating depression and other disorders

Engineers and neuroscientists at Duke University have developed a method to measure the response of an individual neuron to transcranial magnetic stimulation (TMS) of the brain. The advance will help researchers understand the underlying physiological effects of TMS -- a procedure used to treat psychiatric disorders -- and optimize its use as a therapeutic treatment.


The interdisciplinary team that developed the method to record an individual neuron's response during transcranial magnetic stimulation. Clockwise from top left: Michael Platt, director of the Duke Institute for Brain Science, Center for Cognitive Neuroscience; Warren Grill, professor of biomedical engineering, electrical and computer engineering, and neurobiology; Marc Sommer, associate professor of biomedical engineering and neurobiology; and Tobias Egner, assistant professor of psychology and neuroscience.

Credit: Duke University

TMS uses magnetic fields created by electric currents running through a wire coil to induce neural activity in the brain. With the flip of a switch, researchers can cause a hand to move or influence behavior. The technique has long been used in conjunction with other treatments in the hopes of improving treatment for conditions including depression and substance abuse.

While studies have demonstrated the efficacy of TMS, the technique's physiological mechanisms have long been lost in a "black box." Researchers know what goes into the treatment and the results that come out, but do not understand what's happening in between.

Part of the reason for this mystery lies in the difficulty of measuring neural responses during the procedure; the comparatively tiny activity of a single neuron is lost in the tidal wave of current being generated by TMS. But the new study demonstrates a way to remove the proverbial haystack.

The results were published online June 29 in Nature Neuroscience.

"Nobody really knows what TMS is doing inside the brain, and given that lack of information, it has been very hard to interpret the outcomes of studies or to make therapies more effective," said Warren Grill, professor of biomedical engineering, electrical and computer engineering, and neurobiology at Duke. "We set out to try to understand what's happening inside that black box by recording activity from single neurons during the delivery of TMS in a non-human primate. Conceptually, it was a very simple goal. But technically, it turned out to be very challenging."

First, Grill and his colleagues in the Duke Institute for Brain Sciences (DIBS) engineered new hardware that could separate the TMS current from the neural response, which is thousands of times smaller. Once that was achieved, however, they discovered that their recording instrument was doing more than simply recording.

The TMS magnetic field was creating an electric current through the electrode measuring the neuron, raising the possibility that this current, instead of the TMS, was causing the neural response. The team had to characterize this current and make it small enough to ignore.

Finally, the researchers had to account for vibrations caused by the large current passing through the TMS device's small coil of wire -- a design problem in and of itself, because the typical TMS coil is too large for a non-human primate's head. Because the coil is physically connected to the skull, the vibration was jostling the measurement electrode.

The researchers were able to compensate for each artifact, however, and see for the first time into the black box of TMS. They successfully recorded the action potentials of an individual neuron moments after TMS pulses and observed changes in its activity that significantly differed from activity following placebo treatments.

Grill worked with Angel Peterchev, assistant professor in psychiatry and behavioral science, biomedical engineering, and electrical and computer engineering, on the design of the coil. The team also included Michael Platt, director of DIBS and professor of neurobiology, and Mark Sommer, a professor of biomedical engineering.

They demonstrated that the technique could be recreated in different labs. "So, any modern lab working with non-human primates and electrophysiology can use this same approach in their studies," said Grill.

The researchers hope that many others will take their method and use it to reveal the effects TMS has on neurons. Once a basic understanding is gained of how TMS interacts with neurons on an individual scale, its effects could be amplified and the therapeutic benefits of TMS increased.

"Studies with TMS have all been empirical," said Grill. "You could look at the effects and change the coil, frequency, duration or many other variables. Now we can begin to understand the physiological effects of TMS and carefully craft protocols rather than relying on trial and error. I think that is where the real power of this research is going to come from."

###

This research was supported by a Research Incubator Award from the Duke Institute for Brain Sciences and by a grant from the National Institute of Neurological Disorders and Stroke of the National Institutes of Health (grant R21 NS078687).

CITATION: "Optimization Of Transcranial Magnetic Stimulation And Single Neuron Recording Methods For Combined Application In Alert Non-Human Primates." Mueller, J.K., Grigsby, E.M., Prevosto, V., Petraglia III, F.W., Rao, H., Deng, Z., Peterchev, A.V., Sommer, M.A., Egner, T., Platt, M.L., Grill, W.M. Nature Neuroscience, June 29, 2014. DOI:10.1038/nn.3751

Ken Kingery | Eurek Alert!
Further information:
http://www.duke.edu

Further reports about: Brain TMS activity neurons procedure respond technique therapeutic treatments

More articles from Medical Engineering:

nachricht Novel PET tracer identifies most bacterial infections
06.10.2017 | Society of Nuclear Medicine and Molecular Imaging

nachricht Teleoperating robots with virtual reality
05.10.2017 | Massachusetts Institute of Technology, CSAIL

All articles from Medical Engineering >>>

The most recent press releases about innovation >>>

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

Im Focus: Neutron star merger directly observed for the first time

University of Maryland researchers contribute to historic detection of gravitational waves and light created by event

On August 17, 2017, at 12:41:04 UTC, scientists made the first direct observation of a merger between two neutron stars--the dense, collapsed cores that remain...

Im Focus: Breaking: the first light from two neutron stars merging

Seven new papers describe the first-ever detection of light from a gravitational wave source. The event, caused by two neutron stars colliding and merging together, was dubbed GW170817 because it sent ripples through space-time that reached Earth on 2017 August 17. Around the world, hundreds of excited astronomers mobilized quickly and were able to observe the event using numerous telescopes, providing a wealth of new data.

Previous detections of gravitational waves have all involved the merger of two black holes, a feat that won the 2017 Nobel Prize in Physics earlier this month....

Im Focus: Smart sensors for efficient processes

Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).

When quality testing uses time-consuming destructive test methods, it can result in enormous costs due to damaging or destroying the products. And given that...

Im Focus: Cold molecules on collision course

Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.

How do chemical reactions proceed at extremely low temperatures? The answer requires the investigation of molecular samples that are cold, dense, and slow at...

Im Focus: Shrinking the proton again!

Scientists from the Max Planck Institute of Quantum Optics, using high precision laser spectroscopy of atomic hydrogen, confirm the surprisingly small value of the proton radius determined from muonic hydrogen.

It was one of the breakthroughs of the year 2010: Laser spectroscopy of muonic hydrogen resulted in a value for the proton charge radius that was significantly...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ASEAN Member States discuss the future role of renewable energy

17.10.2017 | Event News

World Health Summit 2017: International experts set the course for the future of Global Health

10.10.2017 | Event News

Climate Engineering Conference 2017 Opens in Berlin

10.10.2017 | Event News

 
Latest News

Terahertz spectroscopy goes nano

20.10.2017 | Information Technology

Strange but true: Turning a material upside down can sometimes make it softer

20.10.2017 | Materials Sciences

NRL clarifies valley polarization for electronic and optoelectronic technologies

20.10.2017 | Interdisciplinary Research

VideoLinks
B2B-VideoLinks
More VideoLinks >>>