Slow-wave sleep鈥攖he deeper sleep during which the brain turns each day鈥檚 events into permanent memories鈥攊s fragmented in adulthood in people exposed to high levels of alcohol in the womb.
This is according to a study conducted by researchers at 嘿嘿视频 Medical Center and the聽, part of the New York State Office of Mental Health. The study聽was recently published online in the journal Neuroscience.
When combined with the findings of past studies in humans, the current study in mice suggests a new treatment approach for individuals with fetal alcohol spectrum disorder, which is linked to learning, memory, and mood problems, and is estimated to affect 1 in 100 adults.
According to the authors of the new study, exposure of a developing brain to binge levels of alcohol results in a permanent fragmentation in slow-wave sleep, with the extent of the fragmentation influencing the severity of related cognitive disorders.
鈥淲e have known for a long time that sleep fragmentation is associated with impaired cognitive function, attention, and emotional regulation,鈥 says , a professor in 嘿嘿视频鈥檚 Departments of and , and a member of the NKI. 鈥淥ur study shows for the first time that binge alcohol exposure early in life results in long-lasting slow-wave sleep fragmentation, which, in turn, is associated with learning problems.鈥
鈥淚t appears that some of the consequences of fetal alcohol syndrome stem from changes in the brain鈥檚 ability to regulate sleep,鈥 he adds.
Using a mouse model of fetal alcohol syndrome designed to estimate the third trimester of pregnancy in humans, researchers examined slow-wave sleep in adult mice that were injected once with the equivalent of binge amounts of ethanol, or drinking alcohol, seven days after they were born. Mice in a control group were injected with saline. Mouse brains continue to develop after birth, and seven days post birth in mice equates with third trimester brain development in a human fetus.
Mice exposed to ethanol were found to spend less time in slow-wave sleep and experience severe sleep fragmentation, both with a significant link to memory impairment. The research team also found that the ethanol-exposed mice were hyperactive, but the mice from the control group were not. The ethanol-exposed mice also displayed reduced and fragmented slow-wave sleep and increased sleep/wake transitions over 24 hour periods.
In addition, impaired contextual fear conditioning memory鈥攃haracterized by impairment in memory of events that occurred in specific contexts鈥攚as seen in the ethanol-exposed mice, but not in the control group. The severity of this memory impairment was directly correlated with the extent of sleep fragmentation.
鈥淭argeting therapeutic interventions toward sleep may help to relieve aspects of the diverse disorders linked to fetal alcohol exposure, and may open new avenues for treatment of this far too common condition,鈥 says Wilson.
Other NYU study coauthors include Kurt Masiello, Monica Lewin, Maria Hui, John Smiley, and Mariko Saito. The research was supported by a grant to Wilson and Saito from the National Institute on Alcohol Abuse and Alcoholism (R01-AA023181), part of the National Institutes of Health.
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