Perception of change in depth in the hummingbird hawkmoth Manduca sexta ( Sphingidae, Lepidoptera)

Abstract

Visual perception of depth change can be mediated monocularly by looming the apparent size increase of an approaching object. In Manduca sexta we recorded intracellularly from cells that detect both approach and retreat of an object. The cells compute looming in two fundamentally different ways: class 1 neurons measure the change of perimeter/edge length of the object; class 2 neurons respond to expansion/contraction flowfields. We created a network model incorporating anatomical and physiological properties of class 1 neurons to understand the underlying computational principles for looming detection.