Methodological Approaches to the Behavioural Investigation of Visual Perception in Rodents

Mice and rats have become popular models of visual functions because of the powerful experimental approaches that these species afford in the study of brain processes at the molecular, synaptic and circuitry level. To fully exploit this potential, the application of cutting-edge tools to record and manipulate neuronal activity in in vivo (such as high-resolution two-photon imaging and optogenetics) needs to be combined with the quantitative analysis of rodent visual behaviour. In this chapter, we provide a critical and extensive overview of the methodological approaches that have been applied to investigate visual cognition of laboratory mice and rats. The scope of our survey is very broad, encompassing studies targeting a variety of visual perceptual and memory functions, such as shape processing, object recognition and memory, spatial navigation and innate visually driven responses. The spectrum of behavioural rigs and experimental designs covered by our review is similarly, large, including tests of spontaneous object recognition, several variants of Go/No-Go and two-alternative forced choice tasks, as well as recent implementations of the latter in virtual visual environments. Finally, we also describe the application of advanced psychophysical procedures, such as visual priming paradigms and classification image approaches, to the study of rodent visual perception. As a result, this chapter provides an exhaustive guide for those vision scientists that are interested in dissecting the neuronal processing underlying complex visual behaviours using the simple, yet powerful, brains of mice and rats.