There is considerable concern about the effects of maternal drug use, including alcohol and cocaine, on the developing child. Research has attempted to differentiate the effects of these drugs on development, however, an increased trend toward polydrug abuse has been identified. These studies indicate that polydrug exposed infants appear to be at a greater risk for compromised outcome. Both clinical and animal studies indicate that developmental drug exposure to alcohol and cocaine can result in a number of physiological and behavioral alterations in offspring. Of particular concern is the cognitive development of drug exposed children. Using an animal model, studies described in this proposal will begin to assess the long-term consequences of developmental drug exposure on cognitive functioning. Drug exposure will be focused on the neonatal period in the rat. The neonatal period is characterized by neuronal differentiation and synaptogenesis and thus, may be particularly sensitive to the behavioral teratogenic effects of alcohol and/or cocaine. Cognitive functioning will be assessed using the temporal discrimination procedure, an easily modeled cognitive task in animals. This procedure focuses on time perception; the ability of an animal to discriminate the duration of an event. Studies indicate that brain regions involved in learning and memory may be vulnerable to insults by neonatal exposure to alcohol and/or cocaine. Pilot studies indicate that while learning is not disrupted, neonatal exposure to alcohol and/or cocaine produces alterations in performance in perception and short-term memory tasks. The proposed experiments will further assess learning, perception of time and short-term memory performance. In addition the behavioral strategy and response patterns will be assessed to determine whether alterations in perception and short-term memory performance stem from response inhibition or deficits, hyperactivity or deficits related to temporal coding.
