This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. During 2005, the Developmental Neurotoxicology Program has continued concentrating on the development of the Positron Emission Tomography (PET) procedures to be used in conjunction with complex reaction time behavioral testing. In collaboration with Dr. Satoshi Minoshima, Director of the PET imaging service core at the Primate Center, we have completed training procedures for functional PET imaging in adult Macaca fascicularis prenatally exposed to methylmercury. Changes were made to the reaction time test paradigm and test equipment to accommodate the unique requirements of functional imaging. Pilot runs with saline injections have been achieved. Six successful PET sessions were accomplished in 2005. The brain images from these PET sessions are currently being reviewed. Three individuals in the laboratory, including Dr. Tom Burbacher, are certified in the safe handling of radioactive materials. There are also continued efforts by Drs. Burbacher and Grant to adapt the operant test procedures used in the Developmental Neurotoxicology Program for use with younger animals. To this end, macaque monkeys ranging from 3 months to 1.5 years are being trained to voluntarily enter the testing chair and touch and hold the home bar on the reaction time test panel (a necessary prerequisite for reaction time testing). We are using hold times that vary from .5 seconds to 5 seconds. While most animals can successfully be trained to touch the home bar for brief hold times (up to 3 seconds), longer hold times have proven to be more difficult. Using the shorter touch and hold times, stable reaction times and movement times have been obtained from a subset of animals. Titration of reaction times will be introduced in 2006.
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