Spectrally specific temporal analyses of spike-train responses to complex sounds: A unifying framework
Fig 7
Spectral-domain application of various apPSTHs to spike trains recorded in response to natural speech.
Example of spectral analyses of spike trains recorded from an AN fiber (CF = 1.1 kHz, SR = 64 spikes/s) in response to a vowel snippet of a speech stimulus (s3). (A) Time-domain representation of p(t), n(t), and the stimulus (Stim). n(t) is reflected across the x-axis for display. Signals outside the analysis window are shown in gray. PSTH bin width = 0.1 ms. Number of stimulus repetitions per polarity = 50. Stimulus intensity = 65 dB SPL. (B) Stimulus spectrum (blue, left y-axis). In panels B-E, the frequency-threshold tuning curve (TC θ, black) of the neuron is plotted on the right y-axis. (C) P(f), which shows comparable energy at F0 (130 Hz) and F2 (1.2 kHz). (D) D(f) and S(f). (E) Φ(f) and E(f). Both S(f) and E(f) show peaks near F0. Similarly, both D(f) and Φ(f) show good F2 representations, although D(f) is confounded by the strong F0-related modulation in e(t) as d(t) = e(t) × ϕ(t). The significant representation of F0 in this near-F2 AN fiber response to a natural vowel is inconsistent with the synchrony-capture phenomenon for synthetic stationary vowels.