Making collective sense of brainwaves

November 01, 2018

The lack of tools to be able to pinpoint anomalies in large datasets that vary through time sparked a search by KAUST scientists for new efficiencies to help brain research.

Searching for correlations and similarities in large datasets of time-varying information, such as brain signals, is a formidable task. One technique researchers use to test for such correlation is to analyze the signal's frequency composition: the mix of slow and fast oscillations contained in the waveform. However, these spectral-density analyses contain a lot of low-level background noise, and so it can be difficult to identify genuine correlations from the raw spectral-density function (SDF).

A smoothing process can be applied to reduce noise in the SDF, but the degree of smoothing needs to be optimized to avoid losing the valuable detail in the data needed to pick out real correlations. Normally, this needs to be done for each signal trace before it is compared with others. For an electroencephalogram (EEG) involving tens or hundreds of simultaneous brain signal recordings, this quickly becomes an enormous and inefficient task.

Motivated by the lack of statistical tools for dealing with such problems, KAUST researcher Ying Sun and her doctoral student Tainbo Chen, in collaboration with Mehdi Maadooliat from Marquette University in the United States, developed an efficient method for collectively estimating the SDFs for large numbers of recorded traces.

"Most existing methods either estimate the spectral density separately or suffer from computational issues," says Chen. "Collective estimation is statistically more efficient," he explains, "and by applying a clustering technique to reduce the dimensionality of the data, we could develop a computationally efficient method that outperforms commonly used methods and can also visualize the similarity among time series."

The key challenge in developing this approach was coming up with a way to ensure that the SDFs estimated from the times series were smooth. "Because we only had the observed time-series data to work with, we had to develop a new criterion for estimating the spectral density," says Chen. "We used a measure of how consistent the statistical model is to the data combined with a measure of the smoothness of the estimated function."

The team tested their collective SDF estimation method by using it to detect correlations among brain regions using EEG recordings from 194 electrodes placed on a subject's scalp.

"By clustering the brain signals from different brain locations, we were able to identify brain regions where the EEG signals share similar waveforms," says Chen.

The team has also developed an interactive app that allows anyone to upload their own data and conduct a similar analysis with visualizations.
-end-


King Abdullah University of Science & Technology (KAUST)

Related Brain Regions Articles from Brightsurf:

Brain regions with impaired blood flow have higher tau levels
In Alzheimer's disease, impaired blood flow to brain regions coincides with tau protein buildup.

Got fatigue? Study further pinpoints brain regions that may control it
Scientists at Johns Hopkins Medicine using MRI scans and computer modeling say they have further pinpointed areas of the human brain that regulate efforts to deal with fatigue.

Study reveals greater excitability in social brain regions of autistic men compared to women
New insight on differences in the brains of men and women with autism has been published today in the open-access journal eLife.

Study reveals less connectivity between hey brain regions in people with FXTAS premutation
Investigators from the University of Kansas were able to identify brain processes specifically linked to sensorimotor issues in aging people with the FMR1 premutation.

Brain mapping study suggests motor regions for the hand also connect to the entire body
In a paper publishing March 26 in the journal Cell, investigators report that they have used microelectrode arrays implanted in human brains to map out motor functions down to the level of the single nerve cell.

Analyzing patients shortly after stroke can help link brain regions to speech functions
New research from Rice University and Baylor College of Medicine shows analyzing the brains of stroke victims just days after the stroke allows researchers to link various speech functions to different parts of the brain, an important breakthrough that may lead to better treatment and recovery.

Learning difficulties due to poor connectivity, not specific brain regions
Different learning difficulties do not correspond to specific regions of the brain, as previously thought, say researchers at the University of Cambridge.

Alcohol byproduct contributes to brain chemistry changes in specific brain regions
Study of mouse models provides clear implications for new targets to treat alcohol use disorder and fetal alcohol syndrome.

Childhood obesity linked to structural differences in key brain regions
Obesity in children is associated with differences in brain structure in regions linked to cognitive control compared to the brains of children who are normal weight, according to new research from the University of Cambridge.

How the brain repurposes unused regions
In adults that are born blind, the 'visual' cortex is activated in a similar way during a listening task, according to new research in JNeurosci.

Read More: Brain Regions News and Brain Regions Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.