Effects of prenatal alcohol exposure on the hippocampus: Spatial behavior,electrophysiology, and neuroanatomy

Prenatal exposure to alcohol can result in fetal alcohol syndrome (FAS), ch aracterized by growth retardation, facial dysmorphologies, and a host of ne urobehavioral impairments. Neurobehavioral effects in FAS, and in alcohol-r elated neurodevelopmental disorder, include poor learning and memory, atten tional deficits, and motor dysfunction. Many of these behavioral deficits c an be modeled in rodents. This paper reviews the literature suggesting that many fetal alcohol effects result, at least in part, from teratogenic effe cts of alcohol on the hippocampus. Neurobehavioral studies show that animal s exposed prenatally to alcohol are impaired in many of the same spatial le arning and memory tasks sensitive to hippocampal damage, including T-mazes, the Morris water maze, and the radial arm maze. Direct evidence for hippoc ampal involvement is provided by neuroanatomical studies of the hippocampus documenting reduced numbers of neurons, lower dendritic spine density on p yramidal neurons, and decreased morphological plasticity after environmenta l enrichment in rats exposed prenatally to alcohol. Electrophysiological st udies also demonstrate changes in synaptic activity in in vitro hippocampal brain slices isolated from prenatal alcohol-exposed animals. Considered to gether, these observations demonstrate that prenatal exposure to alcohol ca n result in abnormal hippocampal development and function. Such studies pro vide a better understanding of neurological deficits associated with FAS in humans, and may also contribute to the development of strategies to amelio rate the effects of prenatal alcohol exposure on behavior. Hippocampus 2000 ; 10:94-110. (C) 2000 Wiley-Liss, Inc.