9421039 Rose Sensory processing involves integration of timing from multiple inputs converging on single cells, and production of precisely timed outputs. The structure of single neurons and the biophysical properties of the cell membrane are fundamental features underlying temporal mechanisms in neural circuits in the brain. A valuable system where these properties can be studied easily is in weakly electric fish. These small fish have an electric organ that they discharge to produce an electric field around the animal; they detect tiny electrical signals with sensitive electroreceptors all over the body, and use this electrosense to detect objects in the environment. The electric organ can produce very precisely timed repetitive discharges. Within the midbrain is a remarkable laminated structure called the torus semicircularis. This important center analyzes the spatial and temporal patterns of electrosensory stimuli, and is involved in the behavioral response of the animal to targets in the environment. This project exploits this unique system using sophisticated novel biophysical and behavioral approaches to understand mechanisms of temporal selectivity, the role of cellular morphology and laminated assemblages in temporal filtering, the ways in which the same central circuits contribute to different behavior in different species, and how anticipatory behavior to repetitive stimuli can be learned. Results from this study will have an impact beyond simply the interest in electrosense. The temporal processing studies are important for sensory and computational neuroscience, the comparative discrimination studies for understanding the evolution of neural circuits, the behavioral studies for understanding sensorimotor control mechanisms, and the anticipatory behavior study for understanding learning.
