Visual Sensitivity And Signal Processing In Teleosts

Publisher Summary Fish have adapted to a wide range of habitats, including estuaries, deep sea, lakes, and caves. Accordingly, the characteristics of the visual system vary considerably among species. This chapter presents the research carried out in a small number of species belonging to the cyprinids, such as goldfish ( Carassius auratus ) and zebrafish ( Danio rerio ). Visual sensitivity can be analyzed along three dimensions: absolute, contrast, and spectral sensitivity. The chapter focuses on absolute sensitivity. It describes the characteristics of the visual system in teleost fish and presents current research about absolute visual sensitivity. Circadian modulation of absolute sensitivity and the roles of neurotransmitters, such as dopamine and melatonin are described. The chapter also describes some of the factors that may impair absolute sensitivity. When assessing absolute, contrast, or spectral visual sensitivity, one has to distinguish the level of processing. Visual sensitivities, as determined by photon catch, electroretinogram (ERG) or retinal ganglion cells (RGC) recordings, or behavioral escape responses, optomotor response (OMR), optokinetic response (OKR), are different parameters that do not always correlate.