Fig. 5.

Corticofugal input suppressed collicular activity during the early days of predictable sound exposure

A, Average tuning curves at 70 dB, at 550 μm for control (blue) and predictable (right) groups during the early days of sound exposure. B, Average BF as a function of recording depths for mice during the early days of sound exposure. C, Average BF as a function of recording depths for mice during the early (same as B) and late days of sound exposure. D, Schematic representation of simultaneous inactivation of the AC and recording in the IC. E, Average tuning curves of recorded sound-evoked activity, before (solid lines) and after (dashed lines) muscimol application in the AC, at 70 dB for 550 μm in the IC of the control (blue) and predictable (red) group. The recording was performed in mice with no more than 5 days of sound exposure. F, Similar to E, for mice with 6–11 days of sound exposure. G, Left, pairwise comparison of peak activity before and after cortical inactivation, for mice in the early phase of sound exposure. Wilcoxon signed rank test comparing before and after cortical inactivation: control p = 0.30, predictable p = 0.003. Right, cortical inactivation led to stronger disinhibition in the predictable group (linear mixed effect model with the group factor: p_group = 0.016). Animals and recording sites: control n = 2 and 21, predictable n = 3 and 30. H, Similar to G, for the late phase. Wilcoxon signed rank test comparing before and after cortical inactivation: control p < 0.0001, predictable p = 0.19. Cortical inactivation led to a comparable increase in response gain (linear mixed effect model with the group factor: p_group = 0.24). Animals and recording sites: control n = 3 and 32, predictable n = 5 and 51. I, J, Average BF as a function of recording depths for mice during the early and late phase of sound exposure respectively, before (solid lines) and after (dashed lines) muscimol application in the AC. (For interpretation of the references to colour in this figure legend, the reader is referred to the Web version of this article.)