Brain Circuit Linked to Epilepsy Identified by Researchers

Sunday - July 30 2023, 15:21 UTC - 1 year ago

Researchers have discovered a usual brain circuit that might connect diverse lesion locations leading to epilepsy. They used a technique called lesion network mapping to identify this brain circuit with findings that point to potential targets for brain stimulation. These findings may have clinical implications for predicting the risk of epilepsy after brain damage.

Over 30 million individuals around the globe are affected by focal epilepsy, often linked to brain lesions caused by conditions like stroke. Yet, it remains unclear why certain lesion locations trigger epilepsy while others don’t. A recent study conducted by scientists from the Brigham and Women’s Hospital, a key contributor to the Mass General Brigham healthcare system, discovered a usual brain circuit that might connect diverse lesion locations leading to epilepsy.

In a paper published in JAMA Neurology, the researchers used a technique called lesion network mapping to identify this brain circuit with findings that point to potential targets for brain stimulation.

"We’re learning more and more about where in the brain epilepsy comes from and what brain circuits we need to modulate to treat patients with epilepsy," said lead author Frederic Schaper, MD, Ph.D., an Instructor of Neurology at Harvard Medical School and scientist at the Brigham and Women’s Center for Brain Circuit Therapeutics. "Using a wiring diagram of the human brain, lesion network mapping allows us to look beyond the individual lesion location and map its connected brain circuit." .

Schaper and the team studied 5 datasets of over 1,500 patients with brain lesions. Participating centers across the US and Europe included the Brigham and Women’s Hospital, Massachusetts General Hospital, Boston Children’s Hospital, Northwestern University, and University Hospitals of Turku in Finland, Maastricht in the Netherlands, and Barcelona in Spain. They studied a variety of brain lesions such as stroke, trauma, and tumors, which allowed them to search for common network connections associated with epilepsy across different regions and types of brain damage.

One of the datasets included combat veterans from the Vietnam Head Injury Study, which was originally designed in the 1960s because brain damage from combat shrapnel wounds resulted in a significant increase in the occurrence of epilepsy.

"In our studies, up to 50 percent of Vietnam combat veterans suffered at least one seizure post-injury, sometimes many years after the injury," said co-author Jordan Grafman, Ph.D. of the Shirley Ryan AbilityLab in Chicago. "However, it has remained unclear why lesions to some locations cause epilepsy and others don’t." .

The Brigham researchers compared the locations of brain damage in patients that developed epilepsy to patients that did not, and found that lesions associated with epilepsy were distributed throughout the brain. However, these same lesion locations were connected to a common brain network, suggesting the brain connections disrupted by the lesions, rather than the locations of the lesions themselves, were the key.

These findings may have clinical implications for predicting the risk of epilepsy after brain damage.

"If we can map a lesion to the brain network we identified, we may be able to estimate how likely someone is to get epilepsy after a stroke," Schaper said. "This is not a clinical tool yet, but we lay the groundwork for future studies investigating the use of human brain networks to predict epilepsy risk."The key brain connections they idenified point to potential targets for interventions like brain stimulation.