Prenatal cocaine results in neonatal behavioral delays in rodent infants on postnatal day 21 (2010)
Undergraduate: Amy Abramowitz
Faculty Advisor: Josephine Johns
Department: Psychology & Neuroscience
Crying in humans and ultrasonic vocalizations (USVs) in rats during the neonatal period elicit comforting behaviors from caregivers. Rats that develop normally typically stop vocalizing before postnatal day (PND) 21 when isolated from their litter-mates. During the first year of life neonatal vocalizing patterns change depending on age of testing. Prenatal cocaine exposure (PCE) in both human and rodent neonates has been shown to coincide with abnormal development of crying behaviors. This abnormal crying might increase the risk of caregivers neglecting their infants. Using a rat model of PCE (a model for drug exposure, neglect, and even disorders such as autism in humans) the molecular mechanisms contributing to aberrant neonatal vocalizing behavior can be explored. In this study several acoustic features of USVs in rodent pups on PND 21 were analyzed following chronic prenatal cocaine injections, chronic saline injections, or in litters left untreated. Results suggest that rats prenatally exposed to cocaine continue to exhibit a robust vocalizing behavior through PND 21, a time when pups stop vocalizing in part due to amygdala-induced inhibition. This suggests a delay in normal developmental stages of language following PCE. Future studies will explore neuronal maturation rates in the amygdala to correlate with vocalizing behavior.