Sleep and memory share a complex relationship. Getting enough rest helps the human brain process new information once a person wakes up; whereby, sleeping after learning can consolidate this information into memories, allowing storage in the brain. While that’s generally a good step (even for the bad memories, unfortunately) researchers have uncovered a situation when it is harmful—after a seizure.
New research from the Mayo Clinic shows the brain may inadvertently “learn” to have seizures by treating them like important memories that get stored.
The study found that after a seizure, the brain enters a deep sleep state that mimics memory storage—and this effect can persist into the following night's sleep. In effect, this “saves” the seizure's path like a normal memory, strengthening the disease.
For the study, published in the Journal of Neuroscience, researchers analyzed long-term brain recordings from implanted devices in 11 people with epilepsy. Using these recordings, they compared sleep patterns on nights following seizures to nights when no recent seizures occurred.
The team found that after a seizure, the brain consistently entered a prolonged and intensified state of deep sleep, known as non-rapid eye movement (NREM) sleep. During this period, slow brain waves became stronger and steeper—key features of memory consolidation—particularly within the specific brain regions where seizures originate.
At the same time, rapid eye movement (REM) sleep, which is important for emotional processing and cognitive health, was reduced. On average, patients slept longer and spent more time in deep sleep after seizures, but they experienced less REM sleep compared with seizure-free nights.
The researchers call this process seizure-related consolidation, a phenomenon in which seizures appear to hijack the brain's normal learning mechanisms. Rather than helping the brain recover, this post-seizure sleep state may strengthen abnormal neural circuits, creating a vicious cycle in which each seizure increases the likelihood of future seizures.
“Instead of treating seizures as isolated events, this research shows they may actively shape the brain in ways that promote disease progression,” said lead author of the study Vaclav Kremen, neuroscientist and engineer at Mayo Clinic.
Importantly, the findings point to a potential new window for treatment—the hours and nights after a seizure—when targeted intervention could disrupt this harmful learning process.
"If we can safely intervene during this post-seizure window, we may be able to weaken seizure networks rather than reinforce them,” said senior author Gregory Worrell, M.D., Ph.D., a neurologist at Mayo Clinic.
Data from Mayo Clinic