Tuning in primary saccular afferents of the toadfish (Opsanus tau) revealed by REVCOR analysis

Male toadfish vocalize (e.g., the ‘‘boatwhistle’’ ‐f0 from 100 to 250 Hz) to attract females during mating season. This experiment investigates whether the frequency response of primary saccular afferents is adequate to encode these vocalizations. Whole‐body oscillation (0.1–300 nm displacements) was delivered by a three‐dimensional shaker system driven by noise with a flat spectrum between 50 and 1000 Hz. Stimuli were presented along three orthogonal axes (side–side, front–back, and up–down). Spikes were time stamped with 0.1‐ms resolution. REVCOR functions were averaged accelerometer recordings of the noise triggered by spikes for 51.2 ms before and after each spike. This estimated the impulse response of the linear filtering that preceded spike generation. An FFT of the impulse responses estimated an afferent’s filter shape. Impulse responses obtained were damped oscillations having a major peak indicating the magnitude and direction of excitatory acceleration. In general, filter shapes are low‐pass wi...