The Organization of the Retina and Visual System
Ido Perlman 1. Historical view. As early as 1865 Holmgren found that a light stimulus could cause a change in the electrical potential of the amphibian eye. Shortly afterwards, similar findings were reported by Dewar from Scotland. He showed that light illumination through the pupil, which had previously been covered, caused a …
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Frederic Gaillard and Yves Sauve 1. Introduction Injury to the brain areas concerned with vision can cause a variety of disorders ranging from visual field defects to much more complex deficits like visual agnosia. It all depends on the location and the extent of the damage. Injury to the occipital striate cortex results in corresponding …
Yves Sauve and Frederic Gallard 1. Introduction “…once development was ended, the founts of growth and regeneration of the axons and dendrites dried up irrevocably. In adult centres the nerve paths are something fixed, ended, immutable. Everything may die, nothing may be regenerated. It is for the science of the future to change, if possible, …
Michael Kalloniatis and Charles Luu Dark Adaptation. The eye operates over a large range of light levels. The sensitivity of our eye can be measured by determining the absolute intensity threshold, that is, the minimum luminance of a test spot required to produce a visual sensation. This can be measured by placing a …
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Josh Morgan and Rachel Wong 1. Introduction. Synaptic connections of the vertebrate retina are organized into distinct laminae (Figure 1). In the outer retina, photoreceptors contact horizontal cells and bipolar cells within a single lamina, the outer plexiform layer (OPL). Within the inner retina, synapses between retinal ganglion cells and their presynaptic partners, the …
Haohua Qian Properties of GABA receptors GABA (g-aminobutyric acid) is the main inhibitory neurotransmitter in the central nervous system. The inhibitory action of GABA is mediated by the receptors present on the cell membrane, and results in a reduction of neuronal excitablity. At least three types of GABA receptors have been characterized. Table 1 summarizes …
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Yingbin Fu 1. Introduction. Vertebrates rely on retinal rods and cones for the conventional, image-forming vision while non-image-forming vision is mediated by intrinsically photosensitive retinal ganglion cells (ipRGCs) (see Part II Chapter 7). Rods are specialized for low-light vision. They are extremely sensitive and can signal the absorption of single photons. Cones mediate …
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Helga Kolb 1. General characteristics. Amacrine cells of the vertebrate retina are interneurons that interact at the second synaptic level of the vertically direct pathways consisting of the photoreceptor-bipolar-ganglion cell chain. They are synaptically active in the inner plexiform layer (IPL) and serve to integrate, modulate and interpose a temporal domain to the …
Helga Kolb 1. Circuitry for cone signals. Cone photoreceptors are the sensors of bright light and different wavelengths of light in the retina. They are sensitive in photopic (bright light) conditions and come in several types according to the structure of the visual pigments or opsins in their outer segment regions. In dichromatic …
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1Dustin M. Graham and 2,3Kwoon Y. Wong 1Nature Publishing Group, New York, NY. 2Department of Ophthalmology & Visual Sciences, Department of Molecular, Cellular & Developmental Biology, University of Michigan, Ann Arbor, MI 48105. 3Correspondence: kwoon@umich.edu 1. Introduction. For the greater part of 150 years it was assumed that the mammalian retina contained only …