Behavioral Functioning of the Fetus after Prenatal Toxin Exposure and Neural Insult

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Recent advances in methods for direct observation of the rodent fetus permit behavioral assessment prior to birth. Combined with sensitive quantitative measures of behavior, these techniques have revealed dose-dependent functional deficits in fetal rats after prenatal exposure to methylazoxymethanol (MAM). Pregnant rats were injected i.p. with 10 mg/kg MAM on day 17 (E17) of a 22 day gestation. The fetal offspring were then observed on one of seven prenatal or postnatal ages (E18–E21 and P1, P5, and P10). Dependent measures included interlimb movement synchrony during spontaneous movement, facial wiping (defensive) response to lemon solution, oral grasping and suckling response to a non-nutritive nipple, and hindlimb stepping after mechanical tail stimulation. Collectively, these experiments revealed deficits that emerged in waves across development at the peak expression of each newly emerging behavior. This variability in the timing and expression of behavioral deficits revealed a possible pattern of prenatal behavioral development likely to be observed prior to the delayed emergence of developmental disabilities such as autism, adult onset psychiatric disorders such as schizophrenia, or even late onset neurological disease such as Parkinson's. Because deficits were transient, revealed only at time points early in the peak expression of each behavior, traditional outcome measures are unlikely to detect this type of neural insult. Such results also emphasize the need to elucidate mechanisms that underlie changes in fetal behavior, not only during typical development, but also those that may be differentially altered after exposure to neurotoxins and other prenatal insults.


Meeting abstract of talk from the 32nd Annual Meeting of the Neurobehavioral-Teratology-Society, Monterey, CA, June 28-July 2, 2008.



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