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Research Snapshot: Developing a computational model for understanding brain activity

March 1, 2017 - 2:04pm

There are theories for everything. Newton’s Law is a pillar of physics. Supply and demand is a pillar of economics. But what about neuroscience?

“Scientific laws or models organize observations about the world,”said Kendrick Kay, Ph.D., assistant professor in the Center for Magnetic Resonance Research. “We want that for the brain.”

Right now, there aren’t any comprehensive laws in neuroscience. Researchers don’t have a standard to fall back on when interpreting behavior in the brain. That’s due, in part, to the complexity of the brain and the complexity of human cognition which are incredibly difficult to study. With his colleague Jason Yeatman, Ph.D., assistant professor at the University of Washington, Kay has set out to change that.

They’re creating such a mathematical model to analyze the visual cortex, the part of the brain that processes visual stimuli. The visual cortex connects the dots and gives meaning to what the eyes see.

Kay and Yeatman used functional magnetic resonance imaging (fMRI) to measure neural responses in the brain when study participants viewed different images and acted in response to those images. They were particularly interested in a part of the visual cortex involved with functions like reading and face recognition. This area requires both visual stimuli and internal cognition working together.

“Using fMRI experiments, we have developed the first comprehensive model of how this high-level area of the visual cortex works and how humans process visual input,” said Kay.

The data and proposed model were recently published in eLife.

The model has already shown promise in interpreting how the brain represents stimuli, makes decisions about the stimuli, and how neural responses change when the subject is asked to make a decision about those stimuli.

“It’s really quite novel in its scope,” Kay said. “In our field, it’s rare for people to take this modeling approach and we hope others will join.”

Future research could use this model to provide a standard for analyzing data in neuroscience. It could give insight for developing models of other areas of the brain dealing with emotions, language, motor function, other senses and more.

Down the road, it could also help physicians diagnose visual deficits.

“Right now, we can identify that there is a problem: this child has a perceptual disorder. Let’s say they have trouble recognizing faces. With the right brain measurements, our model might allow someone to isolate which specific processes within the brain appear to be functioning abnormally,” Kay said.

That could lead to insight on how certain brain conditions work, and help researchers develop new treatments. Kay and Yeatman plan to continue collaborating on this research direction. They hope to capitalize on the model to understand how children’s brains change as they learn to read, and why some children struggle learning this skill.

The model is still in the very early stages of development. But, Kay and his colleagues are optimistic about the potential. They hope it can be used by neuroscience researchers around the world – not just the University – to better understand the brain.

“This project is a continual endeavor. We will keep developing better and better models and as we do, we’ll get better and better understanding of the human brain,” Kay said.

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Could MRI be used to help detect cracks in teeth?

August 10, 2016 - 9:23am

Cracked teeth can cause several problems. Cracked teeth can sometimes be treated with a crown, but depending on the severity of the crack, extraction and replacement with a bridge or implant may be the only options.

Magnetic resonance imaging (MRI) technology may be able to help dentists identify those cracks sooner, and intervene before significant damage is done, and/or determine if the tooth is salvable (i.e., not worth crowning), a new study from the University of Minnesota’s School of Dentistry and the Center for Magnetic Resonance Research (CMRR) found.

The study was recently published in DentoMaxillofacial Radiology.

“Dental MRI does not exist in clinical practice and even the wording ‘dental MRI’ sounds strange due to traditional view of MRI as a method totally impractical for imaging of the hard tissues,” said Djaudat Idiyatullin, Ph.D., assistant professor in the CMRR, and first author of the study. “However, in this study we demonstrate that MRI technology can be used not only for imaging a calcified dental tissue, but also, what is more important, to detect microcracks in teeth.”

The proof-of-concept study tested two extracted teeth with known cracks. It was small, but because dental MRI has not been done before, the findings open additional opportunities for research.

“If we’re able to apply this technology to dental care, we may be able to spot cracks in the beginning and prevent patients from tooth loss and pain,” said Don Nixdorf, D.D.S., associate professor in the School of Dentistry.

The team used a specific imaging technique developed by Dr. Idiyatullin and Michael Garwood, Ph.D., professor in the Department of Radiology and the CMRR, along with other CMRR researchers. It’s called SWeep Imaging with Fourier Transformation (SWIFT).

“SWIFT is a unique imaging technique because it allows the MRI machine to capture fast-decaying signal from tissue, which is why regular MRI is not able to image bone and teeth,” said Garwood.

Researchers compared MicroCT, SWIFT and Gradient Echo imaging. Only SWIFT detected the microcracks.

They found that SWIFT imaging could detect cracks 20 micrometers wide, which is 10 times narrower than the imaging voxel size. To put that into perspective, red blood cells are about 10 micrometers wide. Through SWIFT MRI imaging, it may be possible to identify a crack the size of just two such blood cells.

Note, MRI machines are not common. Most machines are large and expensive to build and operate, so it is not feasible to introduce MRI machines into dental offices for routine check-ups yet.

Still, more collaborative projects like this one could lead researchers to identify new ways to apply imaging to dentistry, or ways to make MRI imaging more accessible to the dental field. By continuing to study microcracks, dentists can also improve upon current care practices.

“The dental industry lacks data on best practices for the early diagnosis and treatment of cracks and fractures, largely because dentists don’t have access to effective imaging tools,” said Laurence Gaalaas, D.D.S., assistant professor in the School of Dentistry. “Even if we currently cannot apply this work directly to patient care, using the technology could help us better understand cracks in teeth, and to develop more accurate diagnostic criteria.”

See Also:

MRI helps find cancer needle in a haystack

Pharmacy and dentistry students come together to solve common problem

CMRR and HCMC collaborate to study traumatic brain injury effects on vision

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CMRR’s 10.5 Tesla imaging magnet project moves forward

April 3, 2014 - 8:32am

Last December we took you inside the Center for Magnetic Resonance Research’s (CMRR) latest research project – an effort that will utilize the world’s largest imaging magnet to conduct groundbreaking brain research and human body imaging.

In case you missed it, in late 2013 the 110-ton 10.5 Tesla magnet made a spectacular month-long journey by boat across the Atlantic Ocean from England, through the Great Lakes, and finally made its way from Duluth, MN, to the University of Minnesota campus.

Several months after the magnet’s delivery, we wanted to give Health Talk readers an update on the build-out around the magnet and show you a few behind-the-scenes photos.

A few updates:

  • The construction around the magnet wrapped up in mid-March.
  • The first step in cooling the 10.5T began March 25 when 40,000 liters of liquid nitrogen were pumped into the magnet over a two week period. The liquid nitrogen cools the magnet to 77 Kelvin and allows post-shipment leak checking to occur.
  • Representatives from the magnet manufacturer, Agilent Technologies, will be onsite at CMRR for the next four months as the magnet is cooled and tested.
  • CMRR anticipates the 10.5T magnet will be turned over to the University to begin basic research in late summer 2014.

Stay tuned to Health Talk for more updates on the 10.5T magnet project as they unfold.

The Radiofrequency door seals the magnet room so tight that external radio signals are reduced by more than 100dB and thus cannot interfere with the magnetic resonance signal.

The 10.5T magnet now sits inside the Radiofrequency shielded room. The shield is a full copper enclosure built from 2mm copper sheets. A second enclosure consisting of 600 metric tons of iron shielding also surrounds the copper shielded room. The function of the iron is to contain the ultrahigh magnetic field generated by the 10.5T magnet to the inside of the magnet room.

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Penguin receives MRI at U of M Veterinary Medical Center

October 17, 2013 - 9:00am

Fluffy was having trouble balancing, standing and waddling around when he arrived to the University of Minnesota Veterinary Medical Center in late July.

The male penguin’s radiograph and blood work from his visit to The Raptor Center at the University of Minnesota hadn’t turned up the cause for his illness, so his U of M veterinarian Micky Trent, D.V.M., M.V.S.c., Diplomate A.C.V.S., C.V.S.M.T., was ordering the next step in diagnostic testing:

Fluffy the penguin was about to receive a magnetic resonance imaging scan (MRI).

The middle-aged-penguin was soothed, anesthetized to help him hold still during the scan, and then wheeled across the hall in a hospital bed to where the MRI machine awaited.

A red inflatable pillow helped hold the small penguin in place and a conveyor belt pulled him into the machine where high-power magnets could help veterinarians look inside to find the problem.

The MRI helped Trent discover the source of Fluffy’s ails – an inflammation of the brain, or encephalitis, caused by an infection.

Trent prescribed antibiotics to help fight the infection, and within a few days Fluffy was looking better. By late September, he was back to swimming around rocks and contentedly swallowing fish with his penguin friend BJ.

How’s that for the first known penguin MRI?

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Expert perspectives: Could new imaging advancements help unlock the mysteries of tau proteins in Alzheimer’s patients?

September 23, 2013 - 12:15pm

Last week, researchers from the National Institute of Radiological Sciences in Japan published findings in the journal Neuron signaling that they’d closed in on a diagnostic method to detect tangles of tau proteins previously linked to Alzheimer’s disease.

The work relies on a newly-developed chemical the researchers created that can actually bind to tau proteins in the brain. In turn, positron emission tomography (PET) scanning can then reveal any buildup of these tau proteins in patients suspected of having Alzheimer’s.

So just how big an advancement could this research be?

The cause of the dementia characteristic of Alzheimer’s isn’t yet fully clear, but abnormal clusters of beta-amyloid protein fragments between nerve cells (plaques) and twisted strands of tau proteins (tangles) are suspected to contribute to cell death and tissue loss in the brains of patients suffering Alzheimer’s.

“Imaging tau-containing neurofibrillary tangles is a hot topic in Alzheimer’s research,” said Karen Ashe, M.D., Ph.D., a University of Minnesota neuroscientist and director of the N. Bud Grossman Center for Memory Research and Care. “But whether the structures detected are directly involved in the destruction of the brain or just an indication of invisible pathological processes at work remains unclear.”

Ashe’s research focuses on the mechanisms by which tau and beta-amyloid proteins disrupt brain function. In 2005, she discovered that memory loss is reversible in mice, meaning plaques and tangles aren’t the direct cause of memory loss, but rather symptoms showing the condition has occurred.

Diagnostic detection of tau proteins could someday complement the work of researchers like Ashe as they expand the understanding around the role of beta-amyloid and tau proteins in neurodegeneration, as well as drive the development of medication that could target plaques and tangles.

Eric Karran, M.D., director of research at Alzheimer’s Research UK, alluded to this work when he told the BBC: “With new drugs in development designed to target tau, scans capable of visualising the protein inside the brain could be important for assessing whether treatments in clinical trials are hitting their target.”

Stay tuned to Health Talk for more on future Alzheimer’s advancements.

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