Figure 3. Increased reverberation produces delayed inhibitory fields in dereverberation model kernels and neuronal STRFs.

(A) Histograms of the difference in center of mass of the temporal profiles (for the inhibitory field, $CO{M}^{-}$, blue; excitatory field, $CO{M}^{+}$, red) of dereverberation model kernels between the two different reverberant conditions (large - small room). The $CO{M}^{-}$ were larger in the larger room, with a median difference = 7.9ms. $CO{M}^{+}$ did not differ significantly between the rooms (median difference = 1.0ms). (B) Center of mass differences, plotted as in A, but for the auditory cortical units. The $CO{M}^{-}$ increased in the larger room (median difference = 9.3ms), while $CO{M}^{+}$ was not significantly different (median difference = 0.3ms). (C) Histograms of the large - small room difference in peak time for the temporal profiles of the model kernels (inhibitory, $P{T}^{-}$, blue; excitatory, $P{T}^{+}$, red). The $P{T}^{-}$ values were larger in the larger room (median difference = 5.3ms), whereas $P{T}^{+}$ values were not significantly different (median difference = 0.0ms). (D) Peak time differences for neuronal data, plotted as in C. The $P{T}^{-}$ values increased in the larger room (median difference = 9.4ms), while $P{T}^{+}$ did not significantly differ between between the two rooms (median difference = 0.0ms). Asterisks indicate the significance of Wilcoxon signed-rank tests: ${\displaystyle {}^{\ast \ast \ast \ast }p<0.0001,{}^{\ast \ast }p<0.01}$.

Figure 3—figure supplement 1. Analyses using the Carney Bruce Erfani Zilany (CBEZ) cochlear model.

In order to explore the effects of using more biologically realistic cochlear models on our findings, we repeated the analyses from Figures 2 and 3 using the ‘CBEZ’ cochlear model described in Bruce et al., 2018 and developed from earlier works by Zilany et al., 2014; Zilany et al., 2009; methods as in Rahman et al., 2020 (referred to as the BEZ model there). (A-D) As Figure 2A–D, but using the CBEZ cochlear model. (E-G) As Figure 3A–D, but using the CBEZ cochlear model. (E) Histograms of the difference in center of mass of the temporal profiles (for the inhibitory field, $C\mathrm{}O\mathrm{}{M}^{\mathrm{-}}$, blue; excitatory field, $C\mathrm{}O\mathrm{}{M}^{\mathrm{+}}$, red) of dereverberation model kernels between the two different reverberant conditions (large - small room). The $C\mathrm{}O\mathrm{}{M}^{\mathrm{-}}$ increased in the larger room with a median difference = 10.0ms; $C\mathrm{}O\mathrm{}{M}^{\mathrm{+}}$ decreased slightly in the larger room, median difference = –5.6ms. (F) Center of mass differences, plotted as in E, but for the auditory cortical units. The $C\mathrm{}O\mathrm{}{M}^{\mathrm{-}}$ increased in the larger room, median difference = 12.0ms; $C\mathrm{}O\mathrm{}{M}^{\mathrm{+}}$ increased slightly in the larger room, median difference = 2.7ms. (G) Histograms of the large - small room difference in peak time for the temporal profiles of the model kernels (inhibitory, $P\mathrm{}{T}^{\mathrm{-}}$, blue; excitatory, $P\mathrm{}{T}^{\mathrm{+}}$, red). The $P\mathrm{}{T}^{\mathrm{-}}$ values were larger in the larger room, median difference = 21.0ms, whereas $P\mathrm{}{T}^{\mathrm{+}}$ values were not significantly different, median difference = 0.0ms. (H) Peak time differences for neuronal data, plotted as in G. The $P\mathrm{}{T}^{\mathrm{-}}$ values increased in the larger room, median difference = 12.0ms, and $P\mathrm{}{T}^{\mathrm{+}}$ also showed a significant change, but the median difference was only 0.3ms. Asterisks indicate the significance of Wilcoxon signed-rank tests: ${\displaystyle {}^{\ast \ast \ast \ast }p<0.0001}$.

Figure 3—figure supplement 2. A medium room condition shows intermediate center of mass and peak time values compared to the small and large room conditions.

(A) Violin plots for the center of mass ($CO{M}^{+}$) of the excitatory fields of the neuronal STRFs for the small, medium and large room conditions computed. (B) Same as A, but here the violin plots show the center of mass ($CO{M}^{-}$) of the inhibitory fields for the neuronal STRFs. (C) Violin plots for the peak time of the excitatory fields ($P{T}^{+}$). (D) The same data as (C) but here the violin plots show the peak time ($P{T}^{-}$) of the inhibitory fields. In all violin plots, the white dot represents the median, the horizontal thick line the mean, the thick gray lines the interquartile range, the thin gray lines 1.5 x interquartile range, and the colored shaded area represents the distribution. The results of Kruskal–Wallis tests followed by multiple comparisons using Fisher’s least significant difference (LSD) procedure are indicated above the bars in A, B, and D: ${\displaystyle {}^{\ast }p<0.05{,}^{\ast \ast }p<0.01{,}^{\ast \ast \ast }p<0.001{,}^{\ast \ast \ast \ast }p<0.0001}$.