The Vertebrate Retina

The retina has often been described as a window to the brain because of its accessibility and suitability for scientific investigations. The expansion of brain research over the past decade has demonstrated that these two structures use similar mechanisms and this has spurred new interest in retinal research. The enormous advantage that retinal research enjoys within neuroscience is that we know the retina is responsible for transducing and encoding light signals and we can generate relevant stimuli to evaluate these functions. This is a rare attribute in complex neural tissue, shared by the visual cortex and lateral geniculate. The availability of relevant stimuli has often permitted visual neuroscience to be at the forefront of brain research. Twenty years ago the retina served as a model of cellular neurophysiology as the intricate patterns of intracellular responses and intercellular connections were discovered. Now, the retina is also a model of network systems and information processing, describing how neurons interact to codify and process sensory information. Questions about the role of multiple neurotransmitters, signal transfer at the synapse, and the integrative properties of membrane biophysics are being addressed. In this chapter I would like to give a brief review of retinal anatomy and physiology [see monographs by Rodieck (1973) and Dowling (1987) for detailed descriptions] and then concentrate on recent trends in retinal information processing.