Assesment of Caregiver Experiences and Their Influence on Global DNA Methylation within the Adolescent Hippocampus and Amygdala

Forster, Amy
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University of Delaware
Current neuroscience and developmental psychology research reveals that there are sensitive postnatal periods during which the developing brain has a high level of plasticity. Therefore, early-life experiences can shape neural circuits, determining the structural and functional aspects of brain and behavior throughout the lifespan. More precisely, early-caregiver experiences can produce epigenetic modifications, which are functional and heritable changes to the genome that do not alter the DNA sequence. This study focuses specifically on DNA methylation—an epigenetic alteration that is typically associated with gene silencing and transcriptional suppression—in the ventral hippocampus, dorsal hippocampus, and amygdala. Previous research with adult animals indicates that early-life stress or experiences with a caregiver can epigenetically alter genes in these two regions. However, studies have not examined whether such effects are present during adolescence. This study aimed to quantify levels of 5-methylcytosine (5-mC) within the genome of adolescent rats that were exposed to various caregiving experiences (aversive vs. nurturing) during the first postnatal week of life. Results indicate that exposure to aversive caregiving was associated with significantly higher 5-mC levels in the dorsal hippocampus, and this effect was only present in males. Maltreated males in comparison to maltreated females had higher methylation in the ventral hippocampus, but they did not differ from nurtured controls. Group differences in 5-mC levels were not observed in the amygdala. Together, these data empirically support the hypothesis that early-life caregiver experiences differentially affect the epigenome, and that these effects are present in specific regions of the adolescent brain.
Research Subject Categories::MEDICINE::Morphology, cell biology, pathology::Cell biology::Neuroscience , Neuroscience