Visual matched filtering in vertebrates

Abstract

Despite their large brains, vertebrates extensively filter visual information with numerous adaptations within their eyes, simplifying the stream of neuronal traffic sent centrally and protecting retinal structures from photodamage. Each filtering mechanism can be considered ‘matched’ in the sense that it removes a particular component of incoming light. In this chapter, we consider these peripheral sensory filters of vertebrate eyes. While such eyes are built on a conserved design, they nevertheless incorporate a huge diversity of specialisations, including pigment filters, tuned visual pigments, optical adjustments and retinal sampling variations, all of which enhance the speed and utility of visual perception and simultaneously reduce the energetic cost of vision. Unlike invertebrates, many of whom figuratively re-engineer eye design from the ground up to favour particular visual tasks, vertebrates show enormous plasticity founded on a single fundamental design. This plasticity ranges among species, habitats and even seasons in some species, giving vertebrates as a group the ability to function in any location on earth that provides at least a few photons on which vision can be based.