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  • 1
    Electronic Resource
    Electronic Resource
    Synaptic organization of the dorsal lateral geniculate nucleus in the adult hamster (1985)
    Springer
    Anatomy and embryology 171 (1985), S. 223-234 
    Details
    ISSN: 1432-0568
    Keywords: Lateral geniculate nucleus ; Retinal axons ; Horseradish peroxidase ; Hamster ; Synaptic organization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The synaptic organization of the α sector of the dorsal lateral geniculate nucleus has been examined by electron microscopy in normal adult hamsters and in adult hamsters subjected to unilateral eye enucleation or intravitreal injection of horseradish peroxidase. Two types of neuropil are apparent. Islands of complex neuropil partially enclosed by astrocyte processes (synaptic glomeruli) are surrounded by a sea of simpler non-glomerular neuropil. The latter is dominated by small axon terminals with spherical synaptic vesicles and Gray type 1 axodendritic contacts (SR-boutons) and also contains axon terminals with flattened synaptic vesicles (F-boutons). The glomerular neuropil contains (i) exclusively postsynaptic dendrites and dendritic protrusions of presumptive projection cells; (ii) pre- and postsynaptic pleomorphic-vesiclecontaining P-boutons (interpreted as appendages of the dendrites of interneurons); (iii) large axon terminals containing spherical synaptic vesicles and large pale mitochondria (R-boutons) which were experimentally identified as retinal terminals and which are presynaptic to both projection cell dendrites and P-boutons at Gray type 1 contacts; (iv) F-boutons (minority component). F-boutons and P-boutons are presynaptic to both projection cell dendrites and P-boutons and P-boutons are the intermediate elements of various serial synapses including triplet (triadic) synapses. Medium-large terminals with spherical synatpic vesicles and dark mitochondria (RLD-boutons) which were commonly invaginated by dendritic spines of projection cells in small glomerulus-like formations were also identified. The origin of RLD-boutons is unknown but SR-boutons probably derive chiefly from ipsilateral visual cortex and possibly also from superior colliculus, and non-glomerular F-boutons probably originate in the ipsilateral thalamic reticular nucleus. No differences in synaptic organization were found between the part of the nucleus which receives uncrossed retinal input and the part which receives crossed input, nor were differences seen in the size, fine structure or relationships between the terminals of identified crossed and uncrossed retinal axons.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00341417
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Postnatal development of ipsilateral retino-geniculate projections in normal albino rats and the effects of removal of one eye at birth (1984)
    Springer
    Anatomy and embryology 170 (1984), S. 71-78 
    Details
    ISSN: 1432-0568
    Keywords: Retino-geniculate projection ; Development ; Enucleation ; Horseradish peroxidase ; Albino rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The postnatal development of ipsilateral retinofugal projections to the lateral geniculate body in normal albino rats, and in rats unilaterally enucleated at birth has been examined. At postnatal ages ranging from 1 day to 6 months, horseradish peroxidase was injected into one eye of normal rats and into the remaining eye of neonatally enucleated animals. After approximately 20 hours, the animals were perfused, the brains sectioned and reaction product visualised using tetramethylbenzidine. Ipsilateral retinal projections to the lateral geniculate body in normal animals were extensive on postnatal day 1 and became reduced over the next few days, the adult pattern being established between days 9 and 12. In the enucleated group, the terminal fields of the ipsilateral projections to the lateral geniculate body from the remaining eye remained larger and displayed a greater density of terminal labelling than in age-matched controls. In addition, the ipsilateral terminal field in the dorsal lateral geniculate nucleus occupied a more lateral position than in control animals. These findings support previous suggestions that the abnormally large ipsilateral retino-fugal projections observed in adult rats following removal of one eye, at or close to, birth, result from a failure of the ipsilateral projection to become restricted and that terminal or preterminal sprouting of retinal axons may also make a small contribution to the formation of the exuberant ipsilateral projection.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00319460
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Subcortical afferent and efferent connections of the superior colliculus in the rat and comparisons between albino and pigmented strains (1986)
    Springer
    Experimental brain research 62 (1986), S. 131-142 
    Details
    ISSN: 1432-1106
    Keywords: Superior colliculus ; Horseradish peroxidase ; Connections ; Albinism ; Thalamus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Subcortical connections of the superior colliculus were investigated in albino and pigmented rats using retrograde and anterograde tracing with horseradish peroxidase (HRP), following unilateral injection of HRP into the superior colliculus. Afferents project bilaterally from the parabigeminal nuclei, the nucleus of the optic tract, the posterior pretectal region, the dorsal part of the lateral posterior-pulvinar complex and the ventral nucleus of the lateral lemniscus; and ipsilaterally from the substantia nigra pars reticulata, the pars lateralis of the ventral lateral geniculate nucleus, the intergeniculate leaflet, the zona incerta, the olivary pretectal nucleus, the nucleus of the posterior commissure, the lateral thalamus, Forel's field H2, and the ventromedial hypothalamus. Collicular efferents terminate ipsilaterally in the anterior, posterior and olivary pretectal nuclei, the nuclei of the optic tract and posterior commissure, the ventrolateral part of the dorsal lateral geniculate nucleus, the pars lateralis of the ventral lateral geniculate nucleus, the intergeniculate leaflet, and the zona incerta; and bilaterally in the parabigeminal nuclei and lateral posterior-pulvinar complex (chiefly its dorsal part). The general topographical patterns of some of the afferent and efferent projections were also determined: the caudal and rostral parts of the parabigeminal nucleus project to the caudal and rostral regions, respectively, of the superior colliculus; caudal superior colliculus projects to the most lateral, and lateral superior colliculus to the most caudal part of the terminal field in the dorsal lateral geniculate nucleus; caudolateral superior colliculus projects to the caudal ventrolateral part of the ventral lateral geniculate nucleus, while rostromedial parts of the colliculus project more rostrally and dorsomedially. Following comparable injections in pigmented and albino animals, fewer retrogradely labelled cells were found in subcortical structures in the albino than in the pigmented rats. The difference was most marked in nuclei contralateral to the injected colliculus. Thus, the effects of albinism on the nervous system may be more widespread than previously thought.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00237409
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    Paper (German National Licenses)
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