Design Principles of Insect and Vertebrate Visual Systems

Center for Brain Science, Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, USA.
Neuron (Impact Factor: 15.05). 04/2010; 66(1):15-36. DOI: 10.1016/j.neuron.2010.01.018
Source: PubMed


A century ago, Cajal noted striking similarities between the neural circuits that underlie vision in vertebrates and flies. Over the past few decades, structural and functional studies have provided strong support for Cajal's view. In parallel, genetic studies have revealed some common molecular mechanisms controlling development of vertebrate and fly visual systems and suggested that they share a common evolutionary origin. Here, we review these shared features, focusing on the first several layers-retina, optic tectum (superior colliculus), and lateral geniculate nucleus in vertebrates; and retina, lamina, and medulla in fly. We argue that vertebrate and fly visual circuits utilize common design principles and that taking advantage of this phylogenetic conservation will speed progress in elucidating both functional strategies and developmental mechanisms, as has already occurred in other areas of neurobiology ranging from electrical signaling and synaptic plasticity to neurogenesis and axon guidance.

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    • "referred to as retinotopic map. Neurons of the medulla receive input from the retina and the lamina and are organized into columns and layers and project to the lobula and lobula plate (reviewed in Sanes and Zipursky, 2010). The genetic and cellular mechanisms of neurogenesis in the lobula and lobula plate have only recently been explored in greater detail. "
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    ABSTRACT: Brain development goes through phases of proliferative growth and differentiation to ensure the formation of correct number and variety of neurons. How and when naïve neuroepithelial cells decide to enter a differentiation pathway remains poorly understood. In the Drosophila visual system, four optic ganglia emerge from neuroepithelia of the inner (IPC) and outer (OPC) proliferation centers. Here we demonstrate that the orphan nuclear receptor Tailless (Tll) is a key factor for the development of all optic ganglia. We describe tll expression during larval optic lobe development in unprecedented detail and find a spatiotemporally dynamic pattern. In the larval OPC, symmetrically dividing neuroepithelial cells transform into asymmetrically dividing medulla neuroblast and into lamina precursor cells in a precisely regulated fashion. Using genetic manipulations we found that tll is required for proper neuroepithelium morphology and neuroepithelial cell survival. We show that tll regulates the precise timing of the transition from neuroepithelial cells to medulla neuroblasts. In particular, however, we demonstrate that tll has a crucial role for the specification of lamina precursor cells. We propose that the Tll/Tlx transcription factors have an evolutionary conserved role in regulating neural precursor cell states in the Drosophila optic lobe and in the mammalian retina. Copyright © 2015. Published by Elsevier Inc.
    Developmental Biology 06/2015; DOI:10.1016/j.ydbio.2015.06.011 · 3.55 Impact Factor
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    • "The retina is arguably the best understood part of the vertebrate central nervous system with regard to its cellular patterning , circuitry , and function . It is composed of five major neuron types : photoreceptors , interneurons ( horizontal , bipolar , and amacrine cells ) , and retinal ganglion cells ( RGCs ) that integrate visual information and send it to the brain ( Sanes and Zipursky , 2010 ) . "
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    ABSTRACT: The retina is sensitive to age-dependent degeneration. To find suitable animal models to understand and map this process has particular importance. The degu (Octodon degus) is a diurnal rodent with dichromatic color vision. Its retinal structure is similar to that in humans in many respects, therefore, it is well suited to study retinal aging. Histological, cell type-specific and ultrastructural alterations were examined in 6, 12 and 36 months old degus. The characteristic layers of the retina were present at all ages, but slightly loosened tissue structure could be observed in 36-month-old animals both at light and electron microscopic levels. Elevated glial fibrillary acidic protein expression was observed in Müller glial cells in aging retinas. The number of rod bipolar cells and the ganglion cells was reduced in the aging specimens, while that of cone bipolar cells remained unchanged. Other age-related differences were detected at ultrastructural level: alteration of the retinal pigment epithelium and degenerated photoreceptor cells were evident. Ribbon synapses were sparse and often differed in morphology from those in the young animals. These results support our hypothesis that (i) the rod pathway seems to be more sensitive than the cone pathway to age-related cell loss; (ii) structural changes in the basement membrane of pigment epithelial cells can be one of the early signs of degenerative processes; (iii) the loss of synaptic proteins especially from those of the ribbon synapses are characteristic and (iv) the degu retina may be a suitable model for studying retinal aging.
    Frontiers in Cellular Neuroscience 03/2015; 9(126). DOI:10.3389/fncel.2015.00126 · 4.29 Impact Factor
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    • "Third, the animal has to be able to adapt to environmental changes and to form a sensory memory of new stimuli. Many studies have been dedicated to unraveling the primary transformation from a stimulus into an initial neural representation within various sensory systems (Manni and Petrosini, 2004; Vosshall and Stocker, 2007; Sanes and Zipursky, 2010) and to elucidating neuronal plasticity and sensory memory formation in higher-level processing centers (Heisenberg, 2003; Pasternak and Greenlee, 2005). The ability to extract features and integrate stimulus modalities have so far mainly been studied in the visual system (Livingstone and Hubel, 1988; Bausenwein et al., 1992; Nassi and Callaway, 2009). "
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    eLife Sciences 12/2014; 3:e04147. DOI:10.7554/eLife.04147.001 · 9.32 Impact Factor
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