One of the central roles, if not the primary role, of the cortex is to provide an animal with an appropriate behavioural response to the environmental conditions and challenges it encounters. Current information about the environment can be compared to past experience, mood and motivation taken into account and a behavioural response initiated. A fundamental philosophy of the Kerr group is to allow animal behavior to inform and guide the design of experiments aimed at understanding how the cortex performs is job and how the neuronal circuits central to cortical function operate.We use a combination of imaging techniques and electrophysiology in freely moving and awake head-restrained animals to investigate cortical physiology and function. These techniques include multi-photon imaging of activity in populations of neurons in freely moving rats using a custom-built miniaturized multi-photon microscope, imaging eye movements in freely moving rats using a custom-built miniature ocular videography system, multiphoton-imaging of population activity in head-restrained rats and combined multiphoton imaging and whole-cell patch clamp or juxtasomal extracellular recording. Central to the approach is the design and implementation of behavioural paradigms for investigating the characteristics of neuronal circuit activity during the decision making process. Further, wherever possible we employ experimental designs which allow the animals to move freely and self-determine their interactions with objects and elements in the experimental environment in order to eliminate as many assumptions as possible about their preferred methods of interaction.