Functional Microarchitecture of the Mouse Dorsal Inferior Colliculus Revealed through In Vivo Two-Photon Calcium Imaging.

Due to its genetic tractability, the mouse is fast becoming the most popular animal model for sensory neuroscience. Nevertheless, many aspects of its neural architecture are still poorly understood. Here, we image the dorsal auditory midbrain and its inputs from the cortex, revealing a hitherto hidden level of organization and paving the way for the direct observation of corticocollicular interactions. We show that a precise functional organization exists in the mouse auditory midbrain, which has been missed by previous, more macroscopic approaches. The fine-scale distribution of sound-frequency tuning suggests that the mouse midbrain is more similar to that of other mammals than previously thought and contrasts with the more heterogeneous organization reported in imaging studies of auditory cortex.