Description:
<jats:p>Our natural world is three-dimensional. A fundamental requirement of spatial orientating behaviors in the natural environment is the representation of 3D sensory space. Despite the importance of 3D sensory coding of a natural scene to guide movement, most neurophysiological investigations of this problem have been limited to studies of restrained subjects, tested with 2D, artificial stimuli. Here we show for the first time that auditory neurons in the midbrain superior colliculus of the free-flying echolocating bat encode 3D egocentric sensory space, and that sonar-guided inspection of objects in the environment sharpens spatial tuning of single neurons. Combining wireless multichannel neural recordings from free-flying bats, synchronized with video and audio data, and an echo model that computes the flying animal’s instantaneous, stimulus space, we demonstrate 3D echo-evoked receptive fields of single auditory midbrain neurons in animals orienting in a complex environment. We discovered that the bat’s active sonar inspection of objects dramatically tightens range tuning of single neurons and shifts peak activity to represent closer distances. Our research demonstrates dynamic 3D space coding in a freely moving mammal engaged in a real-world navigation task.</jats:p>