1997 NBTS ABSTRAmS 243

three trimesters in humans. The peak blood alcohol concentration (BAC) was more of a predictor than dose of the amount of brain damage that occurred. The timing of the alcohol exposure also was important. A lower daily dose of alcohol could actually produce more damage than a larger dose, providing that it was consumed over a shorter period of time, producing a higher peak BAC. While alcohol exposure can produce some brain damage during any period of development, clear periods of temporal vulnerability have been identified for some important brain measures. For instance, significant microencephaly and cerebellar Purkinje cell loss occurred only following alcohol exposure during the period of brain development comparable to that which occurs in humans during the third trimester. These data suggest that reducing the incidences of binge drinking and stopping drinking before the beginning of the third trimester may lessen the brain damage associated with fetal alcohol exposure. Supported in part by NIAAA grants AA05523 and AA10090.

NBTS 16

JACOBSON, SW., and J.L. JACOBSON, Department of Psychology, Wayne State University, Detroit, MI. Functional sienificance and expwattern in alcohol

. . teratogemcrty .

Prospective studies of the effects of prenatal alcohol exposure in humans have focused primarily on the detection of subtle deficits. This study was designed to extend those findings by evaluating their functional significance in greater detail. 480 African American infants, recruited to overrepresent moderate-to-heavy prenatal exposure, were assessed. For the five outcomes tested, nonparametric and hockey stick regression analyses both indicated a median threshold of 7 drinks/week. Functional deficit was defined in terms of performance in the bottom 10th percentile. For four outcomes, there was no increased incidence of functional deficit in the infants of mothers less than 30 years old, but those born to older drinking mothers were 2- to Stimes more likely to be functionally impaired. Among the infants whose mothers drank above threshold, 80% of the impaired children were born to women who averaged at least 5 drinks/occasion. These data

are consistent with evidence from animal experiments indicating that peak blood concentration is more critical than average daily intake in determining alcohol teratogenicity.

Supported by Nat’1 Inst on Alcohol Abuse & Alcoholism

NBTS 17 HANNIGAN, J.H. Departments of Obstetrics & Gynecology, and of Psychology, C.S. Mott Center for Human Growth & Development, Fetal Alcohol Research Center, Wayne State

University, Detroit, Michigan. Studies of Potential Treatments for Neurobehavioral Dvsfunction in Animal Models of Fetal Alcohol Svndrome (FAS).

Animal models have defined the biobehavioral outcomes of

prenatal alcohol exposure and allowed the study of risk factors

and mechanisms of FAS and alcohol-related

neurodevelopmental delays (ARNDs), as well as potential

measures for treatment of ARNDs. We will review studies

assessing psychopharmacological and environmental

treatments, and evaluate the implications of selected findings

for future clinical application.

fsychophurmocologicaf studies have evaluated tolerance

between prenatal and postnatal exposures, and responses to

postnatal drug challenges as indices of specific neural

dysfunction(s). However, drugs targeted to specific neural or

behavioral problems, such as physostigmine for cholinergic

deficiency or CNS stimulants for hyperactivity, have not

proved particularly effective in rats. Recent preliminary

studies of neonatal trcatmcnts with novel “nootropic” drugs

may show promise in ameliorating learning deficits.

Using environmental enrichment to facilitate maturation

and improve cognitive performance, we and others have

shown that early postnatal and brief adult “enrichment” can

attenuate deficits in motor function and spatial Icarning. Yet

prenatal alcohol reduces sensitivity to enrichment-induced

changes in hippocampal morphology (i.e., dendritic spine

densities). The parameters of optimal enrichment are being

assessed now, and the apparent dissociation between neural

and behavioral outcomes indicates that brain areas other than

hippocampus may mediate treatment effects.

The results suggest that postnatal treatments may be able to

ameliorate fetal alcohol effects in children. Supported by NIAAA crntcr (PSO-AAO7606) awl rcsc:trrh griants (WI-

AA06721).

NBTS 18 SCHNEIDER, M.L., and A.J. KOEHLER, Departments of Kinesiology and Psychology, University of Wisconsin- Madison, Madison, Wisconsin. The effect of moderate alcohol consumntion and/or