LINKING HUMAN AND ANIMAL NEUROTOXICOLOGY RESEARCH

Behavioral research on the neurotoxic effects of environmental chemicals
is conducted in two isolated worlds. Human performance tests are drawn
from the traditions of achievement, aptitude and intelligence testing
(e.g., Digit Symbol, Santa Ana). Behavioral testing in animals, emerging
from a different tradition, employs techniques such as maze learning,
reinforcement schedules, and complex stimulus discrimination to
investigate potential neurotoxicants. Although the primary differences
between these approaches are methodological rather than conceptual,
efforts to bridge this chasm have been unsuccessful and there has been
little practical or scientific contact between them. As a consequence, the
generality of the extensive animal neurotoxicity literature has rarely
been evaluated, few human-subjects studies acknowledge much less utilize
the animal literature when selecting tests, and efforts to identify and
characterize health effects advance along parallel paths with little
indication they will intersect. The objective of this project is to implement frequently-used animal
behavioral tests in an affordable, efficient, field-ready behavioral test
battery on a laptop computer for human neurotoxicology research. Further,
the proposed test system will replace language-based instructions through
the utilization of shaping and modeling; techniques which been used to
successfully teach complex tasks to animals, children, and a wide range of
educationally-impaired adults. Newly available software will permit the
presentation of motion pictures and animation on the computer screen to
teach the behaviors needed for performance testing to supplement shaping
methods which form the foundation of the training strategy for the new
tests. These tests could thus be employed with virtually any person over
10 years of age, literate or not in English. Test development and availability, however, are insufficient to establish
the needed linkage between the animal and human neurotoxicology research
worlds. To provide the database needed to relate these new tests to the
established tests in human subjects research, parametric testing of
unimpaired males and females will explore the impact of sex, age, culture,
and educational level on the new tests. Tests adopted from animal research
and tests of the same function used in human research will be administered
to the same subjects and the results correlated. Finally, validation
studies with a human population exposed to a representative toxicant,
using tests employed with analogously exposed and damaged animal groups,
will provide the demonstration of significant, reliable relationships
between species. Upon completion, this project will significantly improve
the generalization potential between animal and human research on
neurotoxic chemicals by making animal test methods available, accessible,
and meaningful to neurotoxicologists studying humans.