Navigation Links
Brain's 'radio stations' have much to tell scientists
Date:2/8/2011

Like listeners adjusting a high-tech radio, scientists at Washington University School of Medicine in St. Louis have tuned in to precise frequencies of brain activity to unleash new insights into how the brain works.

"Analysis of brain function normally focuses on where brain activity happens and when," says Eric C. Leuthardt, MD. "What we've found is that the wavelength of the activity provides a third major branch of understanding brain physiology."

Researchers used electrocorticography, a technique for monitoring the brain with a grid of electrodes temporarily implanted directly on the brain's surface. Clinically, Leuthardt and other neurosurgeons use this approach to identify the source of persistent, medication-resistant seizures in patients and to map those regions for surgical removal. With the patient's permission, scientists can also use the electrode grid to experimentally monitor a much larger spectrum of brain activity than they can via conventional brainwave monitoring.

Scientists normally measure brainwaves with a process called electroencephalography (EEG), which places electrodes on the scalp.

Brainwaves are produced by many neurons firing at the same time; how often that firing occurs determines the activity's frequency or wavelength, which is measured in hertz, or cycles per second. Neurologists have used EEG to monitor consciousness in patients with traumatic injuries, and in studies of epilepsy and sleep.

In contrast to EEG, electrocorticography records brainwave data directly from the brain's surface.

"We get better signals and can much more precisely determine where those signals come from, down to about one centimeter," Leuthardt, assistant professor of neurosurgery, of neurobiology and of biomedical engineering, says. "Also, EEG can only monitor frequencies up to 40 hertz, but with electrocorticography we can monitor activity up to 500 hertz. That really gives us a unique opportunity to study the complete physiology of brain activity."

Leuthardt and his colleagues have used the grids to watch consciousness fade under surgical anesthesia and return when the anesthesia wears off. They found each frequency gave different information on how different circuits changed with the loss of consciousness, according to Leuthardt.

"Certain networks of brain activity at very slow frequencies did not change at all regardless of how deep under anesthesia the patient was," Leuthardt says. "Certain relationships between high and low frequencies of brain activity also did not change, and we speculate that may be related to some of the memory circuits."

Their results also showed a series of changes that occurred in a specific order during loss of consciousness and then repeated in reverse order as consciousness returned. Activity in a frequency region known as the gamma band, which is thought to be a manifestation of neurons sending messages to other nearby neurons, dropped and returned as patients lost and regained consciousness.

The results appeared in December in the Proceedings of the National Academy of Sciences.

In another paper that will publish Feb. 9 in The Journal of Neuroscience, Leuthardt and his colleagues have shown that the wavelength of brain signals in a particular region can be used to determine what function that region is performing at that time. They analyzed brain activity by focusing on data from a single electrode positioned over a number of different regions involved in speech. Researchers could use higher-frequency bands of activity in this brain area to tell whether patients:

  • had heard a word or seen a word
  • were preparing to say a word they had heard or a word they had seen
  • were saying a word they had heard or a word they had seen.

"We've historically lumped the frequencies of brain activity that we used in this study into one phenomenon, but our findings show that there is true diversity and non-uniformity to these frequencies," he says. "We can obtain a much more powerful ability to decode brain activity and cognitive intention by using electrocorticography to analyze these frequencies."


'/>"/>

Contact: Michael C. Purdy
purdym@wustl.edu
314-286-0122
Washington University School of Medicine
Source:Eurekalert  

Related biology news :

1. Dynamics of chaperone protein critical in rescuing brains of Alzheimers mice from neuron damage
2. Bat brains offer clues as to how we focus on some sounds and not others
3. Trojan Horse ploy to sneak protective drug into brains of stroke patients
4. The brains of Neanderthals and modern humans developed differently
5. Cockroach brains could be rich stores of new antibiotics
6. Insect brains are rich stores of new antibiotics
7. Caltech: Gain and loss in optimistic versus pessimistic brains
8. Tiny insect brains capable of huge feats
9. Parallel brainstem circuit discovery suggests new path in Parkinsons research
10. Brains, worms and computer chips have striking similarities
11. Psychopaths brains wired to seek rewards, no matter the consequences
Post Your Comments:
*Name:
*Comment:
*Email:
Related Image:
Brain's 'radio stations' have much to tell scientists
(Date:1/15/2016)... Jan. 15, 2016 Recent publicized breaches in ... find new ways to ensure data security and user ... and Android that ties a user,s ... it into a hardware authorization token. Customer service agents ... fingerprint on their KodeKey enabled device to verify their ...
(Date:1/11/2016)... Calif. , Jan. 11, 2016 Synaptics ... human interface solutions, today announced that its ClearPad ® ... integration (TDDI) products won two separate categories in the ... Mobile Innovator and Best Technology Breakthrough. The Synaptics ® ... cost, a simplified supply chain, thinner devices, brighter displays ...
(Date:1/8/2016)... -- NXTD ), a company focused on ... privately held leading direct seller of vacation and entertainment ... company announced that on December 31, 2015, that WorldVentures ... to develop a proprietary new wireless smart card for ... unique smart wallet that serves to securely store all ...
Breaking Biology News(10 mins):
(Date:2/8/2016)... 8, 2016 /PRNewswire/ - BIOREM Inc. (TSXV: BRM) ("Biorem" or ... finalists for clean technology companies in the TSX Venture 50 ... companies listed on the TSX Venture Exchange, in each of ... clean technology & life sciences, diversified industries and technology ... to return on investment, market cap growth, trading volume and ...
(Date:2/8/2016)... ... February 08, 2016 , ... ... Directors. Todorow is the Executive Vice President for Corporate Services and the Chief ... Finance, Accounts Payable, Payroll, Billing Operations, Treasury, Managed Care Contracting, Supply Chain, and ...
(Date:2/8/2016)... -- NanoViricides, Inc. (NYSE MKT: NNVC) (the "Company"), a nanomedicine company developing ... MPH, will present information about the company,s programs at the BIOCEO ... New York City . --> ... 5:30PM EST. Registered attendees can request a one on one meeting ... --> New York City . ...
(Date:2/6/2016)... Virginia (PRWEB) , ... February 06, 2016 , ... ... E-mail: amitchell(at)cee(dot)org , The Center for Excellence in Education Sponsors Teacher Training ... VA – February 4, 2016 – The Center for Excellence in Education (CEE) ...
Breaking Biology Technology: