The brain combats dementia by shifting resources

April 11, 2018, Baycrest Centre for Geriatric Care
The brain combats dementia by shifting resources
Credit: Baycrest Centre for Geriatric Care

The brain continues to put up a fight even as neurodegenerative diseases like dementia damage certain areas and functions. In fact, recent findings in a Baycrest-University of Arizona study suggest that one method the brain uses to counter these diseases is the reassigning of tasks to different regions.

Patients diagnosed with Primary Progressive Aphasia (PPA), a rare form of dementia that robs a person of the ability to communicate, tapped into a different brain region to process the meaning of words, according to an article published in the journal Neuroimage: Clinical. Typically people rely on the left side of the brain to comprehend words we read or hear, but PPA patients showed more brain activity on the right. These findings could be used to help develop targeted treatments to preserve brain function.

Previous studies have shown that this preservation tactic is used after brain damage, such as or stroke, but this is one of the first studies to demonstrate the phenomenon in a neurodegenerative disease.

"These findings offer hope since it demonstrates that despite the brain's degeneration during PPA, it naturally adapts to try and preserve function," says Dr. Jed Meltzer, the senior author, a scientist at Baycrest's Rotman Research Institute (RRI) and Canada Research Chair in Interventional Cognitive Neuroscience. "This compensation suggests there are opportunities to intervene and offer targeted treatment to those areas."

The study captured brain imaging of 28 adults between the ages of 58 and 83, 13 of whom were diagnosed with PPA. While having their brains scanned, research participants were asked to read sentences that appeared on the screen, some of which had grammatical errors or mismatched words.

When a healthy adult processes the sentences with mistakes, there's a spike in brain activity since the brain needs to work harder to make sense of it, says Dr. Meltzer, who is also an assistant professor in the departments of psychology and speech language pathology at the University of Toronto. People with PPA had greater difficulty detecting the mistakes and demonstrated a slower and smaller spike in brain activity when picking up on incorrect words, which could mean they weren't processing them as thoroughly, says Dr. Meltzer. Those with PPA who performed better showed a larger response in the opposite side of the brain, the right, compared to healthy adults.

"We were able to identify regions of the brain that allowed the patients to compensate for the dying of neurons in the brain," says Dr. Aneta Kielar, assistant professor of speech, language and hearing sciences and of cognitive science at the University of Arizona, who did the work as a part of a postdoctoral fellowship at the RRI. She said knowing which areas of the brain people with PPA use to understand language may help in developing treatments.

The slower brain responses could also be used by doctors to assess the disease's severity and lead to treatments being started even earlier, adds Dr. Meltzer. As next steps, scientists are using this data to help treat PPA patients with targeted stimulation. Their work will also explore the short- and long-term effects of this intervention.

Explore further: Long-term memories made with meaningful information

More information: A. Kielar et al, Abnormal language-related oscillatory responses in primary progressive aphasia, NeuroImage: Clinical (2018). DOI: 10.1016/j.nicl.2018.02.028

Related Stories

Long-term memories made with meaningful information

June 20, 2017
When trying to memorize information, it is better to relate it to something meaningful rather than repeat it again and again to make it stick, according to a recent Baycrest Health Sciences study published in NeuroImage.

Brain activity at rest provides clue to intelligence

March 7, 2018
The ability of an adult to learn and to perform cognitive tests is directly linked to how active the brain is at rest, UNSW researchers have found.

Newborn babies who suffered stroke regain language function in opposite side of brain

February 17, 2018
It's not rare that a baby experiences a stroke around the time it is born. Birth is hard on the brain, as is the change in blood circulation from the mother to the neonate. At least 1 in 4,000 babies are affected shortly ...

Bilingualism could offset brain changes in Alzheimer's

February 6, 2018
After more than a decade of research, this much we know: it's good for your brain to know another language.

Can't get an image out of your head? Your eyes are helping to keep it there

February 14, 2018
Even though you are not aware of it, your eyes play a role in searing an image into your brain, long after you have stopped looking at it.

Brain stimulation improves word recall in severe epilepsy

February 7, 2018
Researchers have found that electrically stimulating regions of the brain can improve the ability of people's memory. Their findings were reported in the scientific publication Nature Communications.

Recommended for you

Classifying brain microglia: Which are good and which are bad?

December 6, 2018
Microglia are known to be important to brain function. The immune cells have been found to protect the brain from injury and infection and are critical during brain development, helping circuits wire properly. They also seem ...

Drawing is better than writing for memory retention

December 6, 2018
Older adults who take up drawing could enhance their memory, according to a new study.

Friend or foe? Brain area that controls social memory also triggers aggression

December 5, 2018
Columbia scientists have identified a brain region that helps tell an animal when to attack an intruder and when to accept it into its home. This brain area, called CA2, is part of the hippocampus, a larger brain structure ...

How the brain hears and fears

December 5, 2018
How is it that a sound can send a chill down your spine? By observing individual brain cells of mice, scientists at Cold Spring Harbor Laboratory (CSHL) are understanding how a sound can incite fear.

Adding new channels to the brain remote control

December 5, 2018
By enabling super-fast remote control of specific cells, light-activated proteins allow researchers to study the function of individual neurons within a large network—even an entire brain. Now one of the pioneers of 'optogenetics' ...

Microbial-based treatment reverses autism spectrum social deficits in mouse models

December 4, 2018
An unconventional approach has successfully reversed deficits in social behaviors associated with autism spectrum disorders (ASD) in genetic, environmental and idiopathic mouse models of the condition. Researchers at Baylor ...

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.