CARTER, Lance C.; CHRISTENSEN, Chad L.; ANDERSON, Curt*; Brigham Young Univ., Idaho; Brigham Young Univ., Idaho; Idaho State University: Visual and olfactory projections to the brainstem and spinal cord of the leopard frog, Rana pipiens

Using the leopard frog, Rana pipiens, as a model organism, our lab has been investigating the anatomical basis for sensorimotor integration regulating feeding behavior. Previous research shows sensory inputs for feeding may be integrated in the reticular formation (RF) of the brainstem. If correct, the sensory inputs initiating feeding behavior (olfaction and vision) should converge here, as has been demonstrated with glossopharyngeal (taste) and hypoglossal afferents. Using double labeling (fluorescent tracers or Neurobiotin) and differential interference microscopy, we demonstrate that retinal afferents monosynaptically project to the cerebellum, RF, hypoglossal motor neurons (that activate tongue muscles) and ventral horn motor neurons in the spinal cord. Olfactory projections terminate directly on the cerebellum, RF and hypoglossal motor neurons. Data show that both optic and olfactory nerves are in place for direct activation of hypoglossal neurons and premotor circuits in the reticular formation, but it is unclear whether these two nerves converge on exactly the same cells in the reticular formation. Experiments are ongoing to physiologically verify these anatomical projections. Funded by NIH P20RR16454.