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 'Living bandages': NUST MISIS scientists develop biocompatible anti-burn nanofibers
16.02.2018 | National University of Science and Technology MISIS

nachricht New process allows tailor-made malaria research
16.02.2018 | Eberhard Karls Universität Tübingen

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: Demonstration of a single molecule piezoelectric effect

Breakthrough provides a new concept of the design of molecular motors, sensors and electricity generators at nanoscale

Researchers from the Institute of Organic Chemistry and Biochemistry of the CAS (IOCB Prague), Institute of Physics of the CAS (IP CAS) and Palacký University...

Im Focus: Hybrid optics bring color imaging using ultrathin metalenses into focus

For photographers and scientists, lenses are lifesavers. They reflect and refract light, making possible the imaging systems that drive discovery through the microscope and preserve history through cameras.

But today's glass-based lenses are bulky and resist miniaturization. Next-generation technologies, such as ultrathin cameras or tiny microscopes, require...

Im Focus: Stem cell divisions in the adult brain seen for the first time

Scientists from the University of Zurich have succeeded for the first time in tracking individual stem cells and their neuronal progeny over months within the intact adult brain. This study sheds light on how new neurons are produced throughout life.

The generation of new nerve cells was once thought to taper off at the end of embryonic development. However, recent research has shown that the adult brain...

Im Focus: Interference as a new method for cooling quantum devices

Theoretical physicists propose to use negative interference to control heat flow in quantum devices. Study published in Physical Review Letters

Quantum computer parts are sensitive and need to be cooled to very low temperatures. Their tiny size makes them particularly susceptible to a temperature...

Im Focus: Autonomous 3D scanner supports individual manufacturing processes

Let’s say the armrest is broken in your vintage car. As things stand, you would need a lot of luck and persistence to find the right spare part. But in the world of Industrie 4.0 and production with batch sizes of one, you can simply scan the armrest and print it out. This is made possible by the first ever 3D scanner capable of working autonomously and in real time. The autonomous scanning system will be on display at the Hannover Messe Preview on February 6 and at the Hannover Messe proper from April 23 to 27, 2018 (Hall 6, Booth A30).

Part of the charm of vintage cars is that they stopped making them long ago, so it is special when you do see one out on the roads. If something breaks or...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

2nd International Conference on High Temperature Shape Memory Alloys (HTSMAs)

15.02.2018 | Event News

Aachen DC Grid Summit 2018

13.02.2018 | Event News

How Global Climate Policy Can Learn from the Energy Transition

12.02.2018 | Event News

 
Latest News

Fingerprints of quantum entanglement

16.02.2018 | Information Technology

'Living bandages': NUST MISIS scientists develop biocompatible anti-burn nanofibers

16.02.2018 | Health and Medicine

Hubble sees Neptune's mysterious shrinking storm

16.02.2018 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>