Deactivation, recovery from inactivation, and modulation of extra-synapticion currents in fish retinal ganglion cells

As is shown magnificently by Heron Island's reef the visual environment of many fishes includes various light intensities, hues and shapes that can ch ange on large and small scales in space and time. Several articles in this issue address why fishes are sensitive to some of these properties, and how fishes and other aquatic: species have acquired or fostered these sensitiv ities. This article discusses contributions of extrasynaptic inn currents, in a specific population of neurons, to the detection of ambient light leve ls, the appearance of certain visual stimuli and the disappearance of other s.