Attachment-Based Learning And Bdnf Gene Expression In The Infant Rat Olfactory Bulb

Tania RothInfant-caregiver experiences are known to impact neurobiological and behavioral development. The olfactory and tactile sensory systems are crucial to infant rats’ survival, as they are born blind and deaf. Maternal attachment-based olfactory learning allows for vital behaviors such as orientation to the mother and nipple attachment. Learning occurs throughout development and requires the interaction of the environment and brain, suggesting epigenetic regulation in the brain as a possible mechanism. The brain structures required for olfactory learning prior to postnatal day 10 include the olfactory bulb (OB), locus coeruleus, and anterior piriform cortex. Brain-derived neurotrophic factor (bdnf) is a gene crucial to neuroplasticity, learning, and memory. Environmentally induced epigenetic modifications such as DNA methylation of bdnf result in altered levels of transcription and may lead to altered bdnf gene expression in the OB following odor learning. In this study we employ an odor-stroke conditioning paradigm to promote attraction to peppermint odor. When stroking was paired with presentation of peppermint odor, pups demonstrated an attachment-based preference for peppermint odor 24 hours post-conditioning. This learning paralleled increased expression of bdnf mRNA in the OB 30 minutes postconditioning. Taken together, these data provide evidence that maternal attachmentbased associative learning in the sensitive period rat affects bdnf gene expression in the OB. Future studies will determine whether this reflects experience-dependent epigenetic regulation of bdnf.Neuroscienc