Early-Life Stress Disrupts Attachment Learning: The Role of Amygdala Corticosterone, Locus Ceruleus Corticotropin Releasing Hormone, and Olfactory Bulb Norepinephrine
2009 (English)In: Journal of Neuroscience, ISSN 0270-6474, E-ISSN 1529-2401, Vol. 29, no 50, p. 15745-15755Article in journal (Refereed) Published
Abstract [en]
Infant rats require maternal odor learning to guide pups’ proximity-seeking of the mother and nursing. Maternal odor learning occurs using a simple learning circuit including robust olfactory bulb norepinephrine (NE), release from the locus ceruleus (LC), and amygdala suppression by low corticosterone (CORT). Early-life stress increases NE but also CORT, and we questioned whether early-life stress disrupted attachment learning and its neural correlates [2-deoxyglucose (2-DG) autoradiography]. Neonatal rats were normally reared or stressed-reared during the first 6 d of life by providing the mother with insufficient bedding for nest building and were odor–0.5 mA shock conditioned at 7 d old. Normally reared paired pups exhibited typical odor approach learning and associated olfactory bulb enhanced 2-DG uptake. However, stressed-reared pups showed odor avoidance learning and both olfactory bulb and amygdala 2-DG uptake enhancement. Furthermore, stressed-reared pups had elevated CORT levels, and systemic CORT antagonist injection reestablished the age-appropriate odor-preference learning, enhanced olfactory bulb, and attenuated amygdala 2-DG. We also assessed the neural mechanism for stressed-reared pups’ abnormal behavior in a more controlled environment by injecting normally reared pups with CORT. This was sufficient to produce odor aversion, as well as dual amygdala and olfactory bulb enhanced 2-DG uptake. Moreover, we assessed a unique cascade of neural events for the aberrant effects of stress rearing: the amygdala–LC–olfactory bulb pathway. Intra-amygdala CORT or intra-LC corticotropin releasing hormone (CRH) infusion supported aversion learning with intra-LC CRH infusion associated with increased olfactory bulb NE (microdialysis). These results suggest that early-life stress disturbs attachment behavior via a unique cascade of events (amygdala–LC–olfactory bulb).
Place, publisher, year, edition, pages
Washington, United States: Society for Neuroscience , 2009. Vol. 29, no 50, p. 15745-15755
National Category
Neurosciences
Identifiers
URN: urn:nbn:se:liu:diva-150384DOI: 10.1523/JNEUROSCI.4106-09.2009ISI: 000272837000016PubMedID: 20016090Scopus ID: 2-s2.0-72449201112OAI: oai:DiVA.org:liu-150384DiVA, id: diva2:1240544
Note
This work was funded by National Institutes of Health Grants DC003906 and DC009910, National Science Foun-dation Grant IOB0850527, the Leon Levy Foundation, and the Hope for Depression Foundation (R.M.S.).
2018-08-212018-08-212018-08-29Bibliographically approved