Spectrally specific temporal analyses of spike-train responses to complex sounds: A unifying framework
Fig 4
Modulation-domain internal representations for speech coding can be obtained from PSTH-based envelopes.
PSTH response [p(t)] from one AN fiber (CF = 290 Hz, SR = 12 spikes/s) is shown. (A) Time-domain waveforms for the stimulus (gray) and p(t) (blue). (B) Output of a modulation filter bank after the processing of p(t). Modulation filters were zero-phase, fourth-order, and octave-wide IIR filters. Center frequencies (Fm) for these filters ranged from 2 to 128 Hz (octave spacing), similar to those used in recent psychophysically based SI models (e.g., [16]). PSTH bin width = 0.5 ms. 15 stimulus repetitions. Stimulus intensity = 60 dB SPL.