Adverse Experiences in Early Childhood Cause Brain Adaptations That
Can Lead to Later Psychiatric and Neurological Disorders
DENVER — Adverse experiences both perinatally and during early childhood,
including abuse, neglect and severe medical illness, can have both immediate
and long-term consequences on the development of the central nervous
system, according to accumulating research in rodents and primates.
Investigators from the Department of Psychiatry and Behavioral Sciences
at Emory University School of Medicine will present evidence detailing
neural adaptations to early adverse experiences in a symposium at the
American Association for the Advancement of Science (AAAS) annual meeting
in Denver. The symposium, entitled "Developmental Effects of Deprived
Caregiving" will take place Sat., February 15 at 8:30 am.
These developmental effects,
combined with genetic variations, are believed to lead to changes in
the way external stimuli are perceived and processed and can contribute
to an overall increase in sensitivity to stress, according to Paul Plotsky,
PhD, Emory GlaxoSmithKline professor of psychiatry and behavioral sciences,
who conducted the research along with M.. Mar Sanchez, PhD, and colleagues.
This increased sensitivity to stress is a significant risk factor for
the development of mood disorders and medical diseases.
In a series of studies in
rodents and primates, the Emory researchers studied the development
of pathways and circuitry in the brain to identify target areas that
are vulnerable to negative events; sensitive time periods in brain development;
and genes that potentially are associated with individual variation
in vulnerability or resilience to changes in expectations of care-giving.
Adverse events included perinatal social instability, neonatal maternal
separation, and naturally occurring maltreatment.
Long-term effects related
to adverse events included changes in the neuroendocrine system, increased
anxiety, loss of the feeling of pleasure, changes in social behavior,
changes in sexual behavior, and changes in cognitive performance. The
researchers found that certain areas of the brain experience adaptations
in structure, gene, and protein expression.
Specific changes in expression
of neurotransmitter genes and neurotransmitter hormones included corticotropin
releasing factor (CRF), gamma aminobutyric acid (GABA), and norepinephrine,
all of which are released in response to stress.
"This interrelated system
of neurocircuits that are involved in perceiving and responding to stress
has many targets that are programmed by external stimuli at different
developmental stages," explains Dr. Plotsky. "If the brain is programmed
at key developmental stages in early life to overreact to stressful
stimuli, this stress reaction can carry over inappropriately into adult
The research was supported
by the Silvio O. Conte Center for the Neuroscience of Mental Disease,
the National Institutes of Health and the National Science Foundation.