Investigating cellular vibrations in the cochlea using the continuous wavelet transform and the short-time Fourier transform

The Continuous Wavelet Transform (CWT) and the Short-Time Fourier Transform (STFT) are used to analyze the time course of cellular motion in the guinea-pig inner ear. The velocity responses of individual auditory cells (outer hair cells and Hensen's cells) to amplitude-modulated (AM) acoustical signals display characteristics typical of nonlinear systems. such as harmonic generation. Nonlinear effects are particularly pronounced at the highest stimulus levels, where half-harmonic, and sometimes quarter-harmonic, components are also seen. Both the CWT and the STFT are found to be useful in analyzing these velocity responses.>