Bats use sound waves to see in the dark. Most of the time, big brown bats emit a single 'click' of sound (as shown on the left of the rectangle labelled vocalizations), and a single spike is generated in the brain when the echo of this click is detected (as can be seen on the left of the rectangle labelled neural signal). However, when a bat gets close to an object it emits a double click, which leads to the generation of a more complex signal in the brain (three spikes in this case). Kothari et al. found that during double clicking a group of neurons in the superior colliculus, which is in the midbrain, responded more strongly to close objects. Image credit: Melville Wohlgemuth.