ERIC Number: EJ1175735
Record Type: Journal
Publication Date: 2018-Apr
Abstractor: As Provided
Mechanisms of Critical Period in the Hippocampus Underlie Object Location Learning and Memory in Infant Rats
Travaglia, Alessio; Steinmetz, Adam B.; Miranda, Janelle M.; Alberini, Christina M.
Learning & Memory, v25 n4 p176-182 Apr 2018
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.
Descriptors: Animals, Geographic Location, Learning, Memory, Novelty (Stimulus Dimension), Brain, Statistical Analysis, Infants
Cold Spring Harbor Laboratory Press. 500 Sunnyside Boulevard, Woodbury, NY 11797-2924. Tel: 800-843-4388; Tel: 516-367-8800; Fax: 516-422-4097; e-mail: email@example.com; Web site: http://learnmem.cshlp.org
Publication Type: Journal Articles; Reports - Research
Education Level: N/A
Sponsor: National Institute of Mental Health (DHHS/NIH)
Authoring Institution: N/A
Grant or Contract Numbers: R01MH065635; R01MH074736