CHRONIC POSTNATAL ALCOHOL AND ATTENTION IN THE RAT

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Absent from animal research on alcohol-related birth defects (ARBD) is a systematic analysis of ethanol-induced alterations in basic attentional mechanisms. The proposed research will employ measures of the orienting response, a collection of central, autonomic, and behavioral responses elicited by novel stimuli and believed to index the central process of attention in both animals and humans. The long-term objective of the proposed research is to rigorously investigate basic measures of attention, and to determine how they relate to attentional deficits in an animal model of ARBD. ARBD human infants are known to be impaired in the expression of some of these responses, and further knowledge about these measures may ultimately prove useful as part of a neonatal diagnostic for later attentional dysfunction. These experiments will utilize a postnatal alcohol administration procedure that has been effectively used for studying neuroanatomical changes associated with ARBD. Animals will be intragastrically administered alcohol from postnatal days 4 through 9. In all these experiments ethanol-exposed rats will be compared with controls that will either be sham intubated or handled only. The first experiment will involve measuring blood- and brain-alcohol levels on day 9, both in a chronic ethanol group and in a group of acutely-exposed subjects. The design allows for the assessment of metabolic tolerance to ethanol, and will also provide information about alcohol levels achieved - an important determinant of alcohol's teratogenic effects. The second experiment will examine the effects of postnatal alcohol exposure on the functional development of the autonomic nervous system (ANS) at 12 and 16 days of age. A major component of the orienting response consists of a change in the activity of the parasympathetic division. This experiment will examine possible ethanol-induced alterations in baseline autonomic regulation as well as that of the cardiac response to a novel olfactory stimulus. The third and final experiment will assess ethanol- induced deficits in response habituation and short-term retention for both olfactory and auditory stimuli in preweanling animals. Deficits in response habituation and short-term recognition memory have been reported in FAS/ARBD infants. By systematically evaluating orienting responses, habituation and retention a fuller understanding of these responses and how they are affected by FAS/ARBD will be gained.