Experimental studies of certain sensory systems (e.g., vertebrate retinal cells and auditory fibers) have yielded qualitative evidence of the presence of nonlinear feedback. However, no methods have been available to provide the tools for quantitative analysis of this nonlinear feedback mechanism and subsequent modeling of the overall dynamics of these sensory systems. Recent results offer the analytical means to relate Wiener kernel measurements with corresponding nonlinear feedback models and, thus, the ability to model the overall dynamics of such sensory systems. Furthermore, our analytical results offer an explanation for experimentally observed changes in the waveform of Wiener kernel estimates obtained for different white-noise input mean and/or power levels.