A new study from Kennedy Krieger Institute and Johns Hopkins Medicine reveals how sleep strengthens memory and how epilepsy can disrupt that process.
Researchers found that memory consolidation during sleep depends on coordination of three brain regions. If this coordinated activity is disrupted, memory is impaired.
This is the first human study to directly link interactions between the orbitofrontal cortex, thalamus, and hippocampus to memory. The study gives new insight into how the brain strengthens memory and how epilepsy impacts the sleep-memory system.
This is the first direct evidence of key memory-related brain regions interacting to support the formation of memories while sleeping. The findings show that epileptic spikes can disrupt the brain activity. The new information could shape future approaches to detecting, monitoring, and treating the cognitive impacts of epilepsy.
“We haven’t understood why patients with epilepsy have problems with memory,” said Dr. Catherine Chu, study co-author and vice president of neurology at Kennedy Krieger and director of child neurology and pediatric epilepsy at Johns Hopkins Children’s Center. “This helps to close that gap.”
The study had researchers recording brain activity in the three brain regions in patients with epilepsy. They analyzed how rhythmic patterns of electrical activity coordinated across these areas while patients were asleep. Researchers compared these patterns with memory performance and learned that stronger coordination of electrical activity was linked to better memory. When epileptic spikes occurred, activity was interrupted and memory performance was worse.
“Each brain recording contains an extraordinary amount of information, and we use tools from mathematics and statistics to turn that complexity into clear patterns with clinical relevance,” said Mark Kramer, study co-author and professor of applied mathematics and statistics at Johns Hopkins University Whiting School of Engineering. “These discoveries are possible only because of our interdisciplinary team, no single discipline could have revealed the whole story.”
According to the Epilepsy Foundation Maryland, more than 70,000 Marylanders live with epilepsy. It is the fourth most common neurological or disorder in the world. It is a seizure disorder that can start for the first time in people over age 65 nearly as often as it begins in children. Most people with the disorder can live the same lives as those without it, though they may have restrictions on driving or certain aspects of their professional lives.
There were 19 patients in this study. Is it interesting? Yes. But the way that this piece is written gives false hope.