Understanding retinal function is fundamental to determining how the visual system performs in healthy and diseased states. Many aspects of normal retinal function, such as the framework by which the retina processes visual information in neural networks, are at least partially known. The formation of antagonistic centre-surround receptive fields in ganglion cells, the output neurons of the retina, is an example of how activity in relatively simple synaptic circuits can produce the response archetypes responsible for visual system function. Many diseases of the retina that lead to visual impairment or blindness are associated with genetic or environmentally-induced conditions culminating in the degeneration of neurons. Regardless of origin, pathophysiological changes in the retina are in many cases associated with over-activation of synaptic mechanisms, receptors, and ion channels, the same processes that underlie the orderly processing of visual information in healthy retinas.

The primary aim of the Retina Group is to investigate the function of the retina so that contributions to the following basic and clinical objectives can be made: 1) Discovery of the physiological, pharmacological, and anatomical properties of synaptic circuits and receptive fields in the retina; 2) Identification of therapeutic strategies that could reduce, eliminate or slow damage to retinal neurons in diseases such as glaucoma caused by pathological synaptic and ion channel activity.

A general strategy taken in the retina has receptive fields determined through the synaptic integration of visual information in direct (or centre) neural pathways and lateral (or surround) pathways. Glutamate typically carries the flow of information between neurons in the direct pathway of visual system, that is, from the photoreceptors to bipolar cells and then to ganglion cells. Lateral interactions of horizontal cell and amacrine cell networks that occur through the actions of a host of neurotransmitters and neuromodulators are less well understood. While the bulk of neuromodulation and receptive field formation is mediated by synaptic circuits in neural networks, glial cells too have been implicated in the modulation of retinal performance. The Group will investigate a full spectrum of mechanisms involved in receptive field formation.

Excitatory amino acids, such as glutamate, are also key mediators in excitotoxicity and are the targets in many neuroprotection strategies. Diseases such as glaucoma involve excitatory synaptic circuits, which may in turn involve neuromodulator systems. Improved animal models of these diseases are providing important knowledge of the mechanisms underlying receptive field formation and visual function, an outcome of paramount importance for the diagnosis of disease, the design of neuroprotective therapies, and the measurement of their efficacy. The same synaptic mechanisms that mediate the formation of normal synaptic circuits and receptive fields, may contribute to cellular damage. The Group will advance knowledge of receptive field interpretation and exploit this for clinical applications.

The synergistic research activities of this multidisciplinary Group will lead to new understandings of the molecular and cellular events that govern retinal synaptic function and dysfunction. The knowledge gained will enhance understanding of clinically important retinal diseases and offer novel strategies for their alleviation.