Photos courtesy of Baycrest
By: Dr. Jed Meltzer, Senior Scientist at the Rotman Research Institute, part of the Baycrest Academy for Research and Education (BARE) and Baycrest's Canada Research Chair in Interventional Cognitive Neuroscience
When it comes to dementia and other neurological disorders, knowledge brings hope. The more we understand brain conditions, the better equipped we are to prevent and treat them, with the ultimate goal of improving the lives of those affected. This is why researchers at Baycrest like myself have dedicated our careers to advancing our understanding of the human brain – we work to unlock the potential for breakthroughs in treatment and care through cutting-edge research, interdisciplinary collaboration and innovative education.
In Canada, stroke is just one of the many brain conditions that impact countless individuals and their families and loved ones. More than 100,000 Canadians suffer from stroke every year, making it the leading cause of acquired disability among adults in Canada. Survivors are often left with life-altering symptoms including severe challenges with speech, mobility and cognition.
Strokes leave behind an area where brain cells have died, called a lesion. However, this cannot explain the widespread consequences of stroke, limiting scientists' and clinicians' ability to treat them.
Recently, my team and I published a study that provides hope that innovative, non-invasive treatments could help improve, or even fully reverse, post-stroke symptoms. The study, Secondary thalamic dysfunction underlies abnormal large-scale neural dynamics in chronic stroke, published in the journal Proceedings of the National Academy of Sciences, reveals that an area of the brain distinct from the stroke lesion may play a significant role in causing these symptoms.
This is both good and bad news. The bad news is the impact to the brain caused by stroke is not limited to the lesion seen on a brain scan. The good news is the area that shows abnormal electrical activity outside the lesion might be treatable with innovative new therapies.
Our team, which included researchers from Baycrest, the Centre for Addiction and Mental Health (CAMH) and Simon Fraser University, examined the brain's electrical activity using magnetoencephalography (MEG), and brain structure using magnetic resonance imaging (MRI) of 18 individuals living with language deficits as a result of stroke.
Main findings:
Damage to brain tissue near the stroke lesion was not the primary cause of abnormal brain electrical activity.
Instead, these abnormalities were related to the thalamus, a structure located deep in the centre of the brain that acts like a hub connecting numerous brain areas and activities.
More than the lesion alone, the amount of degeneration in the thalamus predicted the amount of abnormal brain electrical activity measured using MEG, as well as the individual's language and cognitive deficits.
These results suggest that degeneration of the thalamus is a major contributor to post-stroke symptoms. New targeted treatments, such as brain stimulation and medications, could be designed to prevent or even reverse this degeneration, to optimize recovery in stroke survivors.
This work was supported by the Natural Sciences and Engineering Research Council of Canada (NSERC), the Canadian Partnership for Stroke Recovery, the Canada Research Chairs Program, the Krembil Foundation, the CAMH Discovery Fund, the Labatt Family Network and the University of Toronto EMHSeed program.
This Baycrest study is just one of many that are revolutionizing aging and brain health. Baycrest uses our world class expertise to implement innovative approaches to dementia prevention, detection, treatment and care. To learn more about this research, please contact me at: jmeltzer@research.baycrest.org.