Figure 5. Adaptation is confirmed by neural responses to a noise probe and to stimuli that switch between the small and large room.

(A) Average firing rate across all cortical units in response to an anechoic noise burst that was embedded within the reverberant stimuli. Responses to the noise within the small (light green) and large (dark green) rooms are plotted separately. Shaded areas show ± SEM across units. The vertical line indicates the noise onset. (B) Histogram of the difference in center of mass of the neuronal response to the noise probe (shown in A) between the two room conditions (large - small room). The center of mass shifted to a later time in the larger room (median difference = 1.0ms). Asterisks indicate significance of a Wilcoxon signed-rank test: ${\displaystyle {}^{\ast \ast }p<0.01}$. (C) Schematic shows the structure of the ‘switching’ stimulus, which alternates between the large (dark green) and small room (light green) conditions. Letters indicate the reverberant condition in each stimulus block (S: small room, L: large room). Each 8s block within a given room condition was divided for analysis into an early (S1,L1) and late (S2,L2) period. STRFs were fitted to the data from each of the 4 periods independently (S1, S2, L1, L2). (D) Difference in center of mass of inhibitory ($CO{M}^{-}$, blue) and excitatory ($CO{M}^{+}$, red) STRF components between the late and early time period of the small room stimuli (S2 - S1, see A). The $CO{M}^{-}$ decreased in S2 relative to S1 with a median difference = –0.9ms; $CO{M}^{+}$ did not differ significantly, median difference = 0.52ms. (E) Center of mass difference plotted as in B, but for the large room stimuli (L2 - L1). The $CO{M}^{-}$ values were larger in L2 relative to L1, median difference = 1.5ms, while the $CO{M}^{+}$ values were not significantly different, median difference = 0.8ms. Asterisks indicate the significance of Wilcoxon signed-rank tests: ${\displaystyle {}^{\ast \ast }p<0.01,{}^{\ast }p<0.05}$.