Brain regions 'tune' activity to enable attention

January 15, 2014
brain

The brain appears to synchronize the activity of different brain regions to make it possible for a person to pay attention or concentrate on a task, scientists at Washington University School of Medicine in St. Louis have learned.

Researchers think the process, roughly akin to tuning multiple walkie-talkies to the same frequency, may help establish clear channels for communication between areas that detect sensory stimuli.

"We think the brain not only puts regions that facilitate on alert but also makes sure those regions have open lines for calling each other," said first author Amy Daitch, a graduate student researcher.

The results are available in the Proceedings of the National Academy of Sciences.

People who suffer from brain injuries or strokes often have problems paying attention and concentrating.

"Attention deficits in have been thought of as a loss of the resources needed to concentrate on a task," said senior author Maurizio Corbetta, MD, the Norman J. Stupp Professor of Neurology. "However, this study shows that temporal alignment of responses in different brain areas is also a very important mechanism that contributes to attention and could be impaired by brain injury."

Attention lets people ignore irrelevant sensory stimuli, like a driver disregarding a ringing cell phone, and pay attention to important stimuli, like a deer stepping onto the road in front of the car.

To analyze brain changes linked to attention, the scientists used grids of electrodes temporarily implanted onto the brains of patients with epilepsy. Co-senior author Eric Leuthardt, MD, associate professor of neurosurgery and bioengineering, uses the grids to map for surgical removal of brain tissues that contribute to uncontrollable seizures.

With patient permission, the grids also can allow Leuthardt's lab to study human brain activity at a level of detail unavailable via any other method. Normally, Corbetta and his colleagues investigate attention using various forms of magnetic resonance imaging (MRI), which can detect changes in brain activity that occur every 2 to 3 seconds. But with the grids in place, Corbetta and Leuthardt can study the changes that occur in milliseconds.

Before grid implantation, the scientists scanned the brains of seven epilepsy patients, using MRI to map regions known to contribute to attention. With the grids in place, the researchers monitored brain cells as the patients watched for visual targets, directing their attention to different locations on a computer screen without moving their eyes. When patients saw the targets, they pressed a button to let the scientists know they had seen them.

"We analyzed brain oscillations that reflect fluctuations in excitability of a local brain region; in other words, how difficult or easy it is for a neuron to respond to an input," Daitch said. "If areas of the brain involved in detecting a stimulus are at maximum excitability, you would be much more likely to notice the stimulus."

Excitability regularly rises and falls in the cells that make up a given brain region. But these oscillations normally are not aligned between different .

The researchers' results showed that as patients directed their attention, the brain regions most important for paying attention to visual stimuli adjusted their excitability cycles, causing them to start hitting the peaks of their cycles at the same time. In regions not involved in attention, the excitability cycles did not change.

"If the cycles of two brain regions are out of alignment, the chances that a signal from one region will get through to another region are reduced," Corbetta said.

Daitch, Corbetta and Leuthardt are investigating whether knowing not just the location, but also the tempo of the task, allows participants to bring the excitability of their brain regions into alignment more rapidly.

Explore further: Brain structure shows who is most sensitive to pain

More information: Daitch AL, Sharma M, Roland JL, Astafiev SV, Bundy DT, Gaona CM, Snyder AZ, Shulman GL, Leuthardt EC, Corbetta M. Frequency-specific mechanism links human brain networks for spatial attention. Proceedings of the National Academy of Sciences, Nov. 26, 2013.

Related Stories

Brain structure shows who is most sensitive to pain

January 14, 2014
Everybody feels pain differently, and brain structure may hold the clue to these differences.

Speedier scans reveal new distinctions in resting and active brain

August 1, 2013
A boost in the speed of brain scans is unveiling new insights into how brain regions work with each other in cooperative groups called networks.

Researchers uncover cellular mechanisms for attention in the brain

July 26, 2013
The ability to pay attention to relevant information while ignoring distractions is a core brain function. Without the ability to focus and filter out "noise," we could not effectively interact with our environment. Despite ...

'Chemobrain' linked to disrupted brain networks

December 17, 2013
(Medical Xpress)—For some cancer patients, the mental fogginess that develops with chemotherapy lingers long after treatment ends. Now research in breast cancer patients may offer an explanation. 

Daydreaming simulated by computer model

July 12, 2013
(Medical Xpress)—Scientists have created a virtual model of the brain that daydreams like humans do.

Recommended for you

The neural codes for body movements

July 21, 2017
A small patch of neurons in the brain can encode the movements of many body parts, according to researchers in the laboratory of Caltech's Richard Andersen, James G. Boswell Professor of Neuroscience, Tianqiao and Chrissy ...

Faulty support cells disrupt communication in brains of people with schizophrenia

July 20, 2017
New research has identified the culprit behind the wiring problems in the brains of people with schizophrenia. When researchers transplanted human brain cells generated from individuals diagnosed with childhood-onset schizophrenia ...

Scientists discover combined sensory map for heat, humidity in fly brain

July 20, 2017
Northwestern University neuroscientists now can visualize how fruit flies sense and process humidity and temperature together through a "sensory map" within their brains, according to new research.

Scientists reveal how patterns of brain activity direct specific body movements

July 20, 2017
New research by Columbia scientists offers fresh insight into how the brain tells the body to move, from simple behaviors like walking, to trained movements that may take years to master. The discovery in mice advances knowledge ...

Team traces masculinization in mice to estrogen receptor in inhibitory neurons

July 20, 2017
Researchers at Cold Spring Harbor Laboratory (CSHL) have opened a black box in the brain whose contents explain one of the remarkable yet mysterious facts of life.

Speech language therapy delivered through the Internet leads to similar improvements as in-person treatment

July 20, 2017
Telerehabilitation helps healthcare professionals reach more patients in need, but some worry it doesn't offer the same quality of care as in-person treatment. This isn't the case, according to recent research by Baycrest.

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.