In collaboration with other members of the Australian Vision Prosthesis Group we are conducting acute studies on prosthetic vision in the cat model. Using optical imaging of the primary visual cortex combined with targeted electrophysiological recordings we are able to quantify neuronal signals elicited in response to electrical stimulation of the retina. These studies are aimed at informing the development of retinal implants for the restoration of vision in profoundly blind human patients.

Working in collaboration with Dr Geoff Goodhill (University of Queensland) we are studying how the cortex develops in young cats. There is a critical period of brain development in all mammals, including humans. Learning how the brain wires itself up is one of the most fundamental questions to be answered in brain science and has significant medical implications. The main technique in this research is the use of intrinsic optical imaging which allows us to record the neural activity of large regions of the cortex simultaneously.

The visual cortex is a complex organ and is the main pathway towards the development of visual perception. As such it is essential to learn everything we can about how the cortex processes information. We study a range of cortical properties at the single cell level, including speed coding, contrast coding, adaptation and cell classification.

Monkey research is not conducted at the ANU campus. Instead we collaborate with Professor Mike Mustari at the Yerkes National Primate Research Center in the USA and with Professor Marcello Rosa at the Physiology Department, Monash University. The work is aimed at understanding how the visual system operates alongside the motor system. The eye only has a tiny region (the fovea) in which photoreceptors are sufficiently tightly packed to allow high resolution vision. To allow us to see large regions of visual space with high resolution we move our eyes 3 times per second using eye movements called saccades. Each time our fovea lands on a patch of visual space the image is stored in memory until a high resolution image of the whole scene is created. A very large portion of the brain is devoted to the coordination of these eye movements with the visual system.

The cat and monkey visual cortex have a very clear functional structure in which neurons with similar properties are arranged into clusters. Rodents do not have this unique cortical structure. Thus it appears that evolution may have driven different types of functional organisation in different mammalian lines. An aim of my laboratory is to assess the functional architecture of the marsupial cortex. Marsupials are mammals that diverged from the other eutherian mammals around 135 million years ago. By studying modern marsupials we can assess if they have similar cortical structures to cats and monkeys or to rodents. Such investigations offer a chance to identify when and why certain cortical organisations evolved.

The honeybee is a remarkable creature. It is capable of advanced cognitive decisions despite having a brain with only 1 million neurons. Our research is aimed at identifying single neurons that are involved in these complex tasks. The work requires detailed anatomical studies alongside electrophysiological investigations.

The dragonfly is a precision instrument that has evolved to catch flying insects on the wing. The visual system is exquisite. The research conducted here investigates the structure and function of the three simple eyes on the head of the dragonfly. Insects have large compound eyes but also three simple eyes. The latter are very highly developed in dragonflies and appear to have a major role in maintaining flight stability. The research has led to the development of autonomous aerial flying machines.