Daily rhythms are a ubiquitous feature of living systems. Generally, these rhythms are not just passive consequences of cyclic fluctuations in the environment, but instead originate within the organism. In mammals, including humans, the master pacemaker controlling 24-hour rhythms is localized in the suprachiasmatic nuclei of the hypothalamus (SCN). This circadian clock is responsible for the temporal organization of a wide variety of functions, ranging from sleep and food intake, to physiological measures such as body temperature, heart rate and hormone release. Moreover, accumulating evidence suggests that dysfunction of the circadian rhythms due to genetic mutations or environmental factors (i.e., jet-lag or shift work) contribute to the development of many pathologies, including sleep disorders, mood and affective disorders such as major depression, bipolar disorder and schizophrenia, as well as the risk of metabolic and cardiovascular disorders.

About the Editors:

Gianluca Tosini is Professor and Chair of the Department of Pharmacology at Morehouse School of Medicine, Atlanta. P. Michael Iuvone is Professor and Director of Research in the Department of Ophthalmology at Emory University School of Medicine, Atlanta. Douglas G. McMahon is Professor of Biological Sciences and Pharmacology, Associate Director for Education and Training Vanderbilt Brain Institute, and Director of Graduate Studies in Neuroscience at Vanderbilt University, Nashville. Shaun P. Collin is Professor, Deputy Director of the Oceans Institute and Head of the Neuroecology Group at University of Western Australia, Crawley.

1. Introduction.- 2. Fundamental Retinal Circuitry for Circadian Rhythms.- 3. Circadian photoreception: from phototransduction to behaviour.- 4. Role of Melatonin and Dopamine in the Regulation of Retinal Circadian Rhythms.- 5. Circadian Organization of the Vertebrate Retina.- 6. Rhythmicity of the Retinal Pigment Epithelium.- 7. Retinal Circadian Rhythms in Mammals Revealed Using Electroretinography.- 8. Circadian Clock and Light Induced Retinal Damage.- 9. Circadian Rhythms and Vision in Zebrafish.- 10. Circadian Modulation of the Limulus Eye for Day and Night Vision.- 11. Molluscan Ocular Pacemakers: Lessons Learned.