Two stages of bandwidth scaling drives efficient neural coding of natural sounds
Fig 7
Modulation power spectra of natural sound ensembles including vocalizations (VC) and background sounds (BG). The modulation power spectrum is shown for the (A) Fourier-based decomposition (Δf = 30 Hz), (B) cochlear model decomposition and (C) midbrain model decomposition. Whereas the Fourier MPS and cochlear model MPS overemphasize low frequency spectral and temporal modulations, the midbrain model MPS is substantially flatter. Black contours in each graph designate the MPS region accounting for 90% of the total sound power. The modulation entropy of each sound category is listed on the right side of the panel.