Robert Fettiplace

University of Wisconsin-Madison, Madison, Wisconsin ~Professor of Neuroscience. Discovered electrical tuning whereby auditory hair cells have different electrical properties for extracting disparate sound frequencies. Electrical tuning has been found in all vertebrate classes except mammals, and represents a prime example of neuronal computation using voltage-dependent channels. Demonstrated that the frequency of a hair cell's electrical tuning is determined by the number and kinetics of its Ca2+-activated K+ (bk) channels and concluded that different kinetic isoforms of the bk channel are required to cover the frequency range. Described the biophysical properties of the mechanoelectrical transducer channels and discovered that the single-channel conductance changes with cochlear location. This property implies, as with the bk channels, the presence of multiple channel isoforms and accounts for the tonotopic gradients in size and kinetics of mechanotransduction. Demonstrated, contra previous hypotheses, that the mechanotransducer channels occur only at the lower end of each stereociliary tip-link, which is important for understanding mechanisms of adaptation. Introduced a dual-photodiode technique for measuring displacements of a few nanometers and was the first to observe oscillatory hair bundle motion driven by membrane voltage. Showed that force generation by the hair bundle is linked to fast adaptation of the mechanotransducer channels. Fellow, Royal Society.~~