How the hippocampus helps children form lasting memories - Children's National

In a study published in PNAS (Proceedings of the National Academy of Sciences), researchers found that the hippocampal gradient and its distinct connections with cortical systems are essential for memory development in children.

"This study is important because it helps us understand how the hippocampus develops and how it communicates with the rest of the brain to form episodic memory, or long-term memories of specific events," said Hua (Oliver) Xie, PhD, research faculty at Children's National Hospital and assistant professor at The George Washington University.

The big picture

Researchers looked at two resting-state functional magnetic resonance imaging (fMRI) datasets. The primary dataset included 598 participants between the ages of 8 and 21 and a secondary replication dataset of 196 participants from the Nathan Kline Institute (NKI)-Rockland Sample. Participants were scanned for a total of 26 minutes in resting-state where they stayed still, awake and looked at the fixation crosshair.

The results showed that the head and tail of the hippocampus form distinct communication patterns with other brain regions, which can help predict how well children form episodic memories.

As children mature into adolescence, their hippocampus becomes increasingly specialized along its longitudinal axis, contributing to the development of memory and other cognitive functions.

The hold up in the field

Previous studies have primarily focused on the hippocampus, with many researchers treating the anterior and posterior regions as distinct areas of study. By exploring how the hippocampus communicates with other parts of the brain, this study reveals a more comprehensive understanding than before.

"Our research shows that in children, it's more of a gradual transition of function along the hippocampus's long axis, like a color gradient rather than two distinct blocks," Dr. Xie said.

You can read the full study, Longitudinal hippocampal axis in large-scale cortical systems underlying development and episodic memory, in PNAS.

Additional authors from Children's National include Venkata Sita Priyanka Illapani, MS, Lauren T. Reppert, BS, Xiaozhen You, PhD, Manu Krishnamurthy, MS, Madison M. Berl, PhD, William D. Gaillard, MD, Leigh N. Sepeta, PhD