ABSTRACT
The last several decades have seen a great increase in concern regarding possible effects of
exposure to environmental chemicals (including drugs, pesticides, and other commercial
products) on the nervous system. Increases, perceived or real, in the incidence of such
developmental defects as autism or attention deficit disorder, as well as possible
associations between environmental exposure and neurodegenerative diseases, such as
Alzheimer’s disease and Parkinson’s disease, have focused public attention on the brain
as a target for adverse effects of such chemicals (1-4). At the same time, there have been
major advances in neuroscience over the past several decades (recognized by the U.S.
Congress in declaring the 1990s the “Decade of the Brain”), expanding our ability to
understand the function of the nervous system and how a variety of chemical classes may
impact the normal functioning of that system. Impetus for improving our evaluation of the
developing nervous system was further provided by a report from the National Academy
of Sciences (5) issued in 1993, which suggested that in many cases the immature organism
may be more sensitive to adverse effects of environmental chemicals. Subsequent passage
of the Food Quality Protection Act [FQPA] by the U.S. Congress mandated more thorough
assessment by the U.S. Environmental Protection Agency (EPA) of toxicity to the
developing organism for pesticides in food (6), stimulating additional focus on evaluating
neurotoxicity in the young. The U.S. Food and Drug Administration (FDA) also has had an
increased interest in testing in juveniles drugs that have previously been tested in adults
only, in order to provide better data for evaluating safety of these drugs for use in children.
