Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

UC researchers create model of brain’s electrical storm during a seizure

24.02.2005


University of California researchers have created a mathematical model describing the electrical storm that rages during a brain seizure. They say the model, to be published in the March 22 print issue of the Journal of the Royal Society of London Interface, but available now to subscribers online, may eventually help neurologists better understand and treat epilepsy.


A lateral skull radiograph of an epilepsy patient with a series of electrodes implanted into his brain by Dr. Nicholas Barbaro at UCSF. The electrodes allowed neurologists to map the electrical activity produced during the patient’s seizures in preparation for brain surgery. The inset at right highlights the mathematical model of the electrical waves, which was compared with the actual readings from the two electrodes noted. (Image courtesy of UC Regents)


These waves compare observed electrocorticogram (ECoG) readings taken from an epilepsy patient (upper pair of curves) with simulated data from a mathematical model created by UC researchers (lower pair). Within the pairs, the upper ECoG trace was recorded during normal brain activity, while the lower ECoG trace was recorded during a seizure. The results of the simulated data are very similar to the observed readings. (Image by Mark Kramer, courtesy of UC Regents)



"We’re trying to get to the underlying state of the brain that leads to these seizures," said Mark Kramer, a Ph.D. student in UC Berkeley’s Applied Science and Technology Program and lead author of the paper. "Our hope is that the model can highlight potential areas where a seizure can be stopped."

There are several possible causes for the abnormal signaling in epilepsy, including illness, injury, abnormal brain development and an imbalance of the chemical neurotransmitters needed to convey messages in the brain. Some seizures begin in a very specific area of the brain called the "seizure focus" before spreading out, and others, particularly ones linked to genetic causes, appear to start simultaneously in various parts of the brain.


What is clear is that during a seizure, a strong pattern of electrical signals suddenly emerges from the random fluctuations that characterize normal brain activity. The strong waves moving across the cortex may cause sudden, unpredictable sensations or uncontrollable movements during a seizure. "Normal brain waves would resemble jagged lines with no apparent pattern or order on an electroencephalogram (EEG)," said Andrew Szeri, UC Berkeley professor of mechanical engineering and applied science and technology, and principal investigator of the study. "But in the brains of epilepsy patients, the spreading of a seizure is made manifest by strong coherent waves of electrical activity in the cortex."

To model this behavior, the researchers adapted stochastic partial differential equations to describe the architecture of the brain. This same class of equations is used to spot trends in the stock market, weather, or other complex systems that could be affected by random events. They simulated the hyperexcitation of neurons in a portion of the brain and found that the stimulus produced traveling waves of electrical activity.

To test the accuracy of their model, the UC Berkeley researchers teamed up with Dr. Heidi Kirsch, assistant professor of neurology at UC San Francisco’s Epilepsy Center. Kirsch was treating a 49-year-old epilepsy patient whose seizures were not reliably controlled by medication. The patient was diagnosed with mesial temporal sclerosis, a condition in which the hippocampus, the part of the brain that organizes memories, is smaller than normal. "We estimate that two-thirds of patients with epilepsy will respond to medication," said Kirsch, who also co-authored the paper. "For a number of the remaining one-third of patients, surgical removal of the part of the brain where seizures begin may offer a cure. The goal in seizure surgery is to find one spot where the seizure comes from, and when taking it out, to not hurt the patient."

Before surgery, neurologists needed to map the region where the patient’s seizure originated to ensure that they only remove what is necessary. To help neurologists observe the patient’s seizures, 64 electrodes were implanted into his brain for a week. The researchers were thus able to obtain data from six of the patient’s seizures to compare with the mathematical model they had created.

The researchers focused on two subdural electrodes spaced a centimeter apart on the surface of the patient’s brain. They noticed a consistent delay of 25 milliseconds in electrical peaks between the two electrodes, indicating a strong, coherent wave pattern characteristic of a seizure. "The wave signals from both the model and the observational data were similar in shape, frequency and speed of propagation," said Kramer. "That suggests that our model is pretty accurate."

The researchers say this is an early step in creating a model that can provide far more detail about the inner workings of the brain than is possible with electrodes alone. "Electrodes reveal the consequence of the abnormal brain activity, but they don’t get at the cause," said Szeri. "If we understand why and how these strong coherent waves progress over the surface of the brain, then we have a hope of doing something to change the situation by disrupting the signal."

Much like a computer model can reveal more about the structural integrity of a building or the causes of a developing hurricane than is practical or desirable through direct observation, a computer simulation of a brain during a seizure could potentially provide a fuller picture of how and why electrical signals misfire. "This model could provide insight into the pathophysiology of the spread of a seizure," said Kirsch. "Further down the line, this could also help us model the impact of medications and other interventions, to theoretically test how drugs with certain mechanisms will impact the brain."

The researchers point to ongoing research to develop interventions to halt epileptic seizures. Examples of potential directed therapies include focal cooling, in which the part of the brain experiencing a seizure is literally chilled to dampen the seizure, and electrical stimulation of the affected area of the brain to counter the seizure as it’s forming. "Our hope is to provide a model that can be used to evaluate potential seizure treatments so we can move beyond the need for lobectomies," said Szeri.

The National Science Foundation and a Berkeley Fellowship from the University of California helped support this research.

Sarah Yang | EurekAlert!

More articles from Health and Medicine:

nachricht Satellites, airport visibility readings shed light on troops' exposure to air pollution
09.12.2016 | Veterans Affairs Research Communications

nachricht Oxygen can wake up dormant bacteria for antibiotic attacks
08.12.2016 | Penn State

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

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

Im Focus: Electron highway inside crystal

Physicists of the University of Würzburg have made an astonishing discovery in a specific type of topological insulators. The effect is due to the structure of the materials used. The researchers have now published their work in the journal Science.

Topological insulators are currently the hot topic in physics according to the newspaper Neue Zürcher Zeitung. Only a few weeks ago, their importance was...

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...

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

Researchers identify potentially druggable mutant p53 proteins that promote cancer growth

09.12.2016 | Life Sciences

Scientists produce a new roadmap for guiding development & conservation in the Amazon

09.12.2016 | Ecology, The Environment and Conservation

Satellites, airport visibility readings shed light on troops' exposure to air pollution

09.12.2016 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>