Elasmobranch fishes (sharks, skates and rays) have an extremely sensitive and specialized sensory system that is critical for the detection of weak electric fields in their marine environments. This sense is used in finding prey and in orientation. A significant problem is that the fish's own activities such as swimming and respiration, stimulate these electroreceptors. Therefore, mechanisms must exist within the brain for separating responses to important external electric fields as distinct from this self-generated "noise". Previous experiments from this laboratory have shown that such a process is accomplished in the first stages of sensory information-processing in the hindbrain region. A series of physiological and anatomical studies are being conducted to better understand the mechanisms responsible for this noise- reduction process. In general, separating signal information from noise is a problem that has broad significance for understanding how all vertebrate sensory systems operate. Therefore, the results obtained from these experiments are relevant for other sensory systems in all vertebrates species, including humans.
