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Effect of gestational ethanol exposure on long-term memory formation in newborn chicks
Venugopal Rao1, Joydeep D Chaudhuri
1Department of Anatomy, University Malaysia Sarawak, Sarawak, Malaysia.
Insights
Prenatal ethanol exposure in chicks significantly reduced body growth and impaired long-term memory (LTM) formation. This suggests LTM deficits may underlie neurobehavioral issues in Fetal Alcohol Syndrome (FAS).
Area of Science:
- Neuroscience
- Developmental Biology
- Toxicology
Background:
- Fetal alcohol syndrome (FAS) involves craniofacial malformations and developmental delays.
- Even without intellectual disability, FAS can cause learning and behavioral issues, potentially linked to memory impairments.
- Understanding ethanol's impact on developing brains is crucial for FAS research.
Purpose of the Study:
- To investigate the effects of early gestational ethanol exposure on memory formation in chick embryos.
- To explore potential mechanisms behind neurobehavioral disturbances observed in FAS.
Main Methods:
- Chicks were exposed to ethanol via injection into fertilized eggs on gestational days 1-3.
- Physical growth parameters were measured.
- One-trial passive avoidance learning was used to assess memory formation (short-term, intermediate-term, and long-term memory).
Main Results:
- Ethanol-exposed chick embryos showed significantly reduced body parameters compared to controls.
- Long-term memory (LTM) formation was significantly impaired in ethanol-exposed chicks post-training.
- Short-term and intermediate-term memory formation remained unaffected.
Conclusions:
- Early gestational ethanol exposure has detrimental effects on chick embryo development and memory.
- Impaired LTM formation may be a key factor contributing to learning disorders and neurobehavioral abnormalities in FAS.
- The chick model provides insights into FAS-related memory deficits.
Abstract:
Fetal alcohol syndrome (FAS), a condition occurring in some children of mothers who have consumed alcohol during pregnancy, is characterized by craniofacial malformations, and physical and mental retardation. It is significant that even children with history of gestational ethanol exposure but relatively unaffected overall IQ performance, often exhibit learning difficulties and behavioral problems, suggestive of impaired memory formation. Hence, the specific aim of this study was to examine memory formation in chicks exposed to ethanol during early gestation toward the understanding of neurobehavioral disturbances in FAS. Chicks were exposed to alcohol on gestational days 1-3 by injection of ethanol into the airspace of freshly fertilized eggs. The effects of prenatal ethanol on physical growth and development, and memory formation were studied. The one-trial passive avoidance learning paradigm in 1-day-old chicks was used to study memory formation in these chicks. It was observed that chick embryos exposed to 10% ethanol on gestational days 1-3 had significant reduction in all body parameters when compared with appropriate controls. Further, ethanol-exposed chick embryos had significantly impaired (P<.05) long-term memory (LTM) formation after training, though short-term or intermediate-term memory formation was unimpaired. Thus, the findings of the current study demonstrate the detrimental effects of ethanol exposure during early pregnancy on developing chick embryos in general and on memory formation in particular. Hence, it is suggested that impairment in LTM could be a fundamental mechanism for learning disorders and neurobehavioral abnormalities observed in FAS.
