Organization and Responses to Sound in the Mouse Inferior Colliculus

The obvious evolutionary advantage that hearing offers for finding prey, avoiding predators or communication has led to a sensory modality with remarkable properties. In most animals, hearing allows to detect minute pressure changes in the surroundings, but still works at sound intensities that are more than 1010 fold higher (Schnupp et al., 2011). An example of a highly evolved auditory organ can be found in bats. Bats can use the echoes of ultrasonic pulses they emit to localize prey and to fly in pitch dark in a forest (Griffin and Galambos, 1941; Payne, 1971). Humans rely heavily on hearing for communication; it allows us to have a conversation in a noisy bar or to detect a person's gender, mood and approximate age in a few seconds without seeing the person. This general introduction describes anatomical and physiological properties of this remarkable sensory system, with an emphasis on the inferior colliculus (IC) and on mechanisms that allow the mammalian brain to decode complex sounds.