Hippocampal Ripples linked to Declarative Memory Judgments in Children

Intracranial studies in adults have revealed significant roles for hippocampal ripples in human declarative memory. Yet, the developmental trajectory of ripples and their involvement in memory processes in children are currently unknown. We studied hippocampal ripple activity using intracranial recordings in 14 children (age: 6-14) undergoing epilepsy monitoring. After watching a pink panther cartoon twice, participants underwent an old/new recognition test, where they determined whether the events portrayed in short video clips (4s) originated from the cartoon they had just viewed or a different one. We found a significant increase in ripple rate specifically during clips recognized as familiar. The ripple rate remained unchanged when the same animated events were viewed as part of the original full-length screenings, outside the context of a recognition test. We conclude that like in adults, hippocampal ripples in children are robustly activated during declarative memory judgments, supporting the explicit identification of previously encountered events. ### Competing Interest Statement The authors have declared no competing interest.