Maternal attenuation of hypothalamic paraventricular nucleus norepinephrine switches avoidance learning to preference learning in preweanling rat pups
2007 (English)In: Hormones and Behavior, ISSN 0018-506X, E-ISSN 1095-6867, Vol. 52, no 3, p. 391-400Article in journal (Refereed) Published
Abstract [en]
Infant rats learn to prefer stimuli paired with pain, presumably due to the importance of learning to prefer the caregiver to receive protection and food. With maturity, a more ‘adult-like’ learning system emerges that includes the amygdala and avoidance/fear learning. The attachment and ‘adult-like’ systems appear to co-exist in older pups with maternal presence engaging the attachment system by lowering corticosterone (CORT). Specifically, odor–shock conditioning (11 odor–0.5 mA shock trials) in 12-day-old pups results in an odor aversion, although an odor preference is learned if the mother is present during conditioning. Here, we propose a mechanism to explain pups ability to ‘switch’ between the dual learning systems by exploring the effect of maternal presence on hypothalamic paraventricular nucleus (PVN) neural activity, norepinephrine (NE) levels and learning. Maternal presence attenuates both PVN neural activity and PVN NE levels during odor–shock conditioning. Intra-PVN NE receptor antagonist infusion blocked the odor aversion learning with maternal absence, while intra-PVN NE receptor agonist infusion permitted odor aversion learning with maternal presence. These data suggest maternal control over pup learning acts through attenuation of PVN NE to reduce the CORT required for pup odor aversion learning. Moreover, these data also represent pups’ continued maternal dependence for nursing, while enabling aversion learning outside the nest to prepare for pups future independent living.
Place, publisher, year, edition, pages
Elsevier, 2007. Vol. 52, no 3, p. 391-400
Keywords [en]
Corticosterone, Attachment, Fear conditioning, Amygdala, Infant, Microdialysis, Paraventricular nucleus, Norepinephrine
National Category
Behavioral Sciences Biology
Identifiers
URN: urn:nbn:se:liu:diva-150389DOI: 10.1016/j.yhbeh.2007.06.004ISI: 000249637700014PubMedID: 17675020Scopus ID: 2-s2.0-34547936158OAI: oai:DiVA.org:liu-150389DiVA, id: diva2:1240567
2018-08-212018-08-212018-08-30Bibliographically approved