Tag: Contextual Memories

Mechanisms of critical period in the hippocampus underlie object location learning and memory in infant rats

Mechanisms of critical period in the hippocampus underlie object location learning and memory in infant rats

Published in: Learning & Memory, Volume 25, Issue 4, 176-182

Abstract
“Episodic memories in early childhood are rapidly forgotten, a phenomenon that is associated with “infantile amnesia,” the inability of adults to remember early-life experiences. We recently showed that early aversive contextual memory in infant rats, which is in fact rapidly forgotten, is actually not lost, as reminders presented later in life reinstate a long-lasting and context-specific memory. We also showed that the formation of this infantile memory recruits in the hippocampus mechanisms typical of developmental critical periods. Here, we tested whether similar mechanisms apply to a nonaversive, hippocampal type of learning. We report that novel object location (nOL) learned at postnatal day 17 (PN17) undergoes the typical rapid forgetting of infantile learning. However, a later reminder reinstates memory expression. Furthermore, as for aversive experiences, nOL learning at PN17 engages critical period mechanisms in the dorsal hippocampus: it induces a switch in the GluN2A/2B-NMDA receptor ratio, and brain-derived neurotrophic factor injected bilaterally into the dorsal hippocampus immediately after training results in long-lasting memory expression. We conclude that in infancy the hippocampus plays a necessary role in processing episodic and contextual memories, including nonaversive ones, and matures through a developmental critical period.”

Written by: Alessio Travaglia, Adam B. Steinmetz, Janelle M. Miranda, Cristina M. Alberini
For full text: http://learnmem.cshlp.org/content/25/4/176.full

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