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 MRI technique induces strong, enduring visual association
01.07.2016 | Brown University

nachricht Innovative device allows 3-D imaging of the breast with less radiation
17.06.2016 | DOE/Thomas Jefferson National Accelerator Facility

All articles from Medical Engineering >>>

The most recent press releases about innovation >>>

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

Im Focus: Mapping electromagnetic waveforms

Munich Physicists have developed a novel electron microscope that can visualize electromagnetic fields oscillating at frequencies of billions of cycles per second.

Temporally varying electromagnetic fields are the driving force behind the whole of electronics. Their polarities can change at mind-bogglingly fast rates, and...

Im Focus: Continental tug-of-war - until the rope snaps

Breakup of continents with two speed: Continents initially stretch very slowly along the future splitting zone, but then move apart very quickly before the onset of rupture. The final speed can be up to 20 times faster than in the first, slow extension phase.phases

Present-day continents were shaped hundreds of millions of years ago as the supercontinent Pangaea broke apart. Derived from Pangaea’s main fragments Gondwana...

Im Focus: A Peek into the “Birthing Room” of Ribosomes

Scaffolding and specialised workers help with the delivery – Heidelberg biochemists gain new insights into biogenesis

A type of scaffolding on which specialised workers ply their trade helps in the manufacturing process of the two subunits from which the ribosome – the protein...

Im Focus: New protocol enables analysis of metabolic products from fixed tissues

Scientists at the Helmholtz Zentrum München have developed a new mass spectrometry imaging method which, for the first time, makes it possible to analyze hundreds of metabolites in fixed tissue samples. Their findings, published in the journal Nature Protocols, explain the new access to metabolic information, which will offer previously unexploited potential for tissue-based research and molecular diagnostics.

In biomedical research, working with tissue samples is indispensable because it permits insights into the biological reality of patients, for example, in...

Im Focus: Computer Simulation Renders Transient Chemical Structures Visible

Chemists at the University of Basel have succeeded in using computer simulations to elucidate transient structures in proteins. In the journal Angewandte Chemie, the researchers set out how computer simulations of details at the atomic level can be used to understand proteins’ modes of action.

Using computational chemistry, it is possible to characterize the motion of individual atoms of a molecule. Today, the latest simulation techniques allow...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

GROWING IN CITIES - Interdisciplinary Perspectives on Urban Gardening

15.07.2016 | Event News

SIGGRAPH2016 Computer Graphics Interactive Techniques, 24-28 July, Anaheim, California

15.07.2016 | Event News

Partner countries of FAIR accelerator meet in Darmstadt and approve developments

11.07.2016 | Event News

 
Latest News

Hey robot, shimmy like a centipede

22.07.2016 | Information Technology

New record in materials research: 1 terapascals in a laboratory

22.07.2016 | Physics and Astronomy

University of Graz researchers challenge 140-year-old paradigm of lichen symbiosis

22.07.2016 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>