Tuning and timing in the gerbil ear: Wiener-kernel analysis

Information about the tuning and timing of excitation in cochlear axons with low-characteristic frequency (CF) is embodied in the first-order Wiener kernel, or reverse correlation function. For high-CF axons, the highest-ranking eigenvector (or singular vector) of the second-order Wiener kernel often can serve as a surrogate for the first-order kernel, providing the same information. For mid-CF axons, the two functions are essentially identical. In this paper we apply these tools to gerbil cochlear-nerve axons with CFs ranging from 700 Hz to 14 kHz. Eigen or singular-value decomposition of the second-order Wiener kernel allows us to separate excitatory and suppressive effects, and to determine precisely the timing of the latter.