Assesment of Caregiver Experiences and Their Influence on Global DNA Methylation within the Adolescent Hippocampus and Amygdala
Date
2015-05
Authors
Forster, Amy
Journal Title
Journal ISSN
Volume Title
Publisher
University of Delaware
Abstract
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.
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Research Subject Categories::MEDICINE::Morphology, cell biology, pathology::Cell biology::Neuroscience , Neuroscience