One of the first investigations on pediatric patients to use intracranial EEG.
A Northwestern Medicine scientist and colleagues from Wayne State University discovered that as brains mature, the precise ways in which two key memory regions in the brain communicate improve our ability to form lasting memories in a new, rare study of direct brain recordings in children and adolescents. The results also point to how the brain learns to multitask as it gets older.
The work will be published in Current Biology on February 15th
Due to a dearth of high-resolution data from children’s brains in the past, our knowledge of how the growing brain develops memories has been limited. The research was the first to utilize an intracranial electroencephalogram (iEEG) on young patients to look at how brain growth affects memory.
During that 16-year span, the scientists discovered a correlation between how people’s brains developed and how effectively they were able to construct memories. For example, younger children with less developed brains than the teenage participants were unable to generate as many memories as the adolescents.
contributing author Lisa Johnson, associate professor of medical social sciences and pediatrics at Northwestern University Feinberg School of Medicine, stated, “Our research helps us truly understand how memory grows, not simply that it develops.” “Knowing how something comes to be — in this case, memory — provides us insights into why it inevitably breaks apart.”
“Human memory grows throughout infancy, peaks in your twenties, then decreases with age for the vast majority of individuals, including those who do not suffer dementia.”
To address this, her research focuses on memory throughout the lifetime to give a comprehensive knowledge of brain development and memory, which is why this study focused on children.
Rhythms in the brain’s main memory areas
The research looked at communication between two brain areas that are important in memory formation: the medial temporal lobe (MTL) and the prefrontal cortex (PFC). The researchers looked at two brain signals that allow these areas to communicate with one another: a slowly oscillating brain wave and a rapidly oscillating brain wave. The rhythms determined whether a memory was effectively established and distinguished top-performing adolescents and youngsters from those who did not.
Intracranial EEG was the first to be used in pediatric patients
The researchers took advantage of a rare chance to analyse data from electrodes put directly on the exposed surface of the brain since the volunteers were already having brain surgery for another reason (typically to treat their epilepsy).
Patients stayed in the hospital for a week after brain surgery to be monitored. Johnson’s team performed their research around this time, asking participants to look at photos of settings to assess how well they recalled them. The researchers showed them the same photographs plus fresh settings they hadn’t seen before (for example, a different image of an outside region) to determine whether there were any age-related changes in how well they recalled what they’d seen.
With age, our brains learn to multitask
Another unexpected result in the research is that rapid and slow theta oscillations — brain rhythms that aid cognition, behavior, learning, and memory — seem to alter with age. With aging, the slow theta frequency decreases, while the rapid theta frequency increases.
“These rhythms tended to vary with age, with 5-year-olds having comparable rhythms and 20-year-olds having distinct rhythms,” Johnson added. “The interaction of important memory areas at both frequencies shows how your brain learns to multitask as you grow older.”
Johnson’s study, which she completed while at Wayne State University, lays the groundwork for a new research program she’s beginning with the Ann & Robert H. Lurie Children’s Hospital of Chicago.
The study’s principal author is Noa Ofen of Wayne State University.
