An anatomical investigation of projections from lateral geniculate nucleus to visual cortical areas 17 and 18 in newborn kitten

1982 ◽  
Vol 46 (2) ◽  
pp. 177-185 ◽  
Author(s):  
Z. Henderson
Keyword(s):  
Lateral Geniculate Nucleus ◽  
Cortical Areas ◽  
Newborn Kitten ◽  
Lateral Geniculate ◽  
Areas 17 And 18 ◽  
Visual Cortical

Corticotectal circuit in the cat: a functional analysis of the lateral geniculate nucleus layers of origin

1988 ◽  
Vol 59 (6) ◽  
pp. 1783-1797 ◽  
Author(s):  
C. L. Colby
Keyword(s):  
Superior Colliculus ◽  
Lateral Geniculate Nucleus ◽  
Dorsal Lateral Geniculate Nucleus ◽  
Visual Responses ◽  
Cortical Input ◽  
Cortical Areas ◽  
Lateral Geniculate ◽  
Contralateral Eye ◽  
Visual Cortical ◽  
Y Cells

1. The dorsal lateral geniculate nucleus (LGN) of the cat is a major thalamic relay between the retina and several visual cortical areas. These cortical areas in turn project to the superior colliculus (SC). The aim of the present experiment was to determine which LGN layers provide a necessary input to the corticotectal circuit. 2. Individual layers of the LGN were reversibly inactivated by microinjection of cobalt chloride during recording of visual responses in the retinotopically corresponding part of the superior colliculus. 3. For cells driven through the contralateral eye, inactivation of layer A or the medial interlaminar nucleus (MIN) had little effect on visual responsiveness in the superior colliculus. In contrast, inactivation of layer C abolished visual responses at one-quarter of the SC recording sites, reduced responses at another quarter, and left half of the recording sites unaffected. 4. For cells driven through the ipsilateral eye, inactivation of layer C1 or the MIN had no effect. Inactivation of layer A1 uniformly reduced visual responses in the superior colliculus and usually abolished them entirely. 5. These results are compatible with previous work showing that cortical input to the SC originates from Y-cells. They indicate that two of the five Y-cell containing layers (A1 and C) provide major inputs to the corticotectal circuit. The results suggest that layer A1 is functionally allied to layer C as well as to layer A.

An examination of linking hypotheses drawn from the perceptual consequences of experimentally induced changes in neural circuitry

2013 ◽  
Vol 30 (5-6) ◽  
pp. 271-276 ◽  
Author(s):  
DONALD E. MITCHELL ◽  
STEPHEN G. LOMBER
Keyword(s):  
Striate Cortex ◽  
Extended Period ◽  
Monocular Deprivation ◽  
Specific Cell ◽  
Cortical Areas ◽  
Good Spatial Resolution ◽  
Areas 17 And 18 ◽  
Visual Cortical ◽  
Areas Of Interest ◽  
Induced Changes

AbstractBecause targeted early experiential manipulations alter both perception and the response properties of particular cells in the striate cortex, they have been used as evidence for linking hypotheses between the two. However, such hypotheses assume that the effects of the early biased visual input are restricted to just the specific cell population and/or visual areas of interest and that the neural populations that contribute to the visual perception itself do not change. To examine this assumption, we measured the consequences for vision of an extended period of early monocular deprivation (MD) on a kitten (from 19 to 219 days of age) that began well before, and extended beyond, bilateral ablation of visual cortical areas 17 and 18 at 132 days of age. In agreement with previous work, the lesion reduced visual acuity by only a factor of two indicating that the neural sites, other than cortical areas 17 and 18, that support vision in their absence have good spatial resolution. However, these sites appear to be affected profoundly by MD as the effects on vision were just as severe as those observed following MD imposed on normal animals. The pervasive effects of selected early visual deprivation across many cortical areas reported here and elsewhere, together with the potential for perception to be mediated at a different neural site following deprivation than after typical rearing, points to a need for caution in the use of data from early experiential manipulations for formulation of linking hypotheses.

Topographic organization, number, and laminar distribution of callosal cells connecting visual cortical areas 17 and 18 of normally pigmented and Siamese cats

1992 ◽  
Vol 9 (1) ◽  
pp. 1-19 ◽  
Author(s):  
Nancy E. J. Berman ◽  
Simon Grant
Keyword(s):  
Pyramidal Neurons ◽  
Area 17 ◽  
Vertical Meridian ◽  
Cortical Areas ◽  
Area Centralis ◽  
Areas 17 And 18 ◽  
Contralateral Eye ◽  
Visual Cortical ◽  
Callosal Pathway ◽  
Cell Zone

AbstractThe callosal connections between visual cortical areas 17 and 18 in adult normally pigmented and “Boston” Siamese cats were studied using degeneration methods, and by transport of WGA-HRP combined with electrophysiological mapping. In normal cats, over 90% of callosal neurons were located in the supragranular layers. The supragranular callosal cell zone spanned the area 17/18 border and extended, on average, some 2–3 mm into both areas to occupy a territory which was roughly co-extensive with the distribution of callosal terminations in these areas. The region of the visual field adjoining the vertical meridian that was represented by neurons in the supragranular callosal cell zone was shown to increase systematically with decreasing visual elevation. Thus, close to the area centralis, receptive-field centers recorded from within this zone extended only up to 5 deg into the contralateral hemifield but at elevations of -10 deg and -40 deg they extended as far as 8 deg and 14 deg, respectively, into this hemifield. This suggests an element of visual non-correspondence in the callosal pathway between these cortical areas, which may be an essential substrate for “coarse” stereopsis at the visual midline.In the Siamese cats, the callosal cell and termination zones in areas 17 and 18 were expanded in width compared to the normal animals, but the major components were less robust. The area 17/18 border was often devoid of callosal axons and, in particular, the number of supragranular layer neurons participating in the pathway were drastically reduced, to only about 25% of those found in the normally pigmented adults. The callosal zones contained representations of the contralateral and ipsilateral hemifields that were roughly mirror-symmetric about the vertical meridian, and both hemifield representations increased with decreasing visual elevation. The extent and severity of the anomalies observed were similar across individual cats, regardless of whether a strabismus was also present. The callosal pathway between these visual cortical areas in the Siamese cat has been considered “silent,” since nearly all neurons within its territory are activated only by the contralateral eye. The paucity of supragranular pyramidal neurons involved in the pathway may explain this silence.

Age dependent modification of cytochrome oxidase activity in the cat dorsal lateral geniculate nucleus following removal of primary visual cortex

1996 ◽  
Vol 13 (5) ◽  
pp. 805-816 ◽  
Author(s):  
Bertram R. Payne ◽  
Stephen G. Lomber
Keyword(s):  
Visual Cortex ◽  
Cytochrome Oxidase ◽  
Lateral Geniculate Nucleus ◽  
Oxidase Activity ◽  
Dorsal Lateral Geniculate Nucleus ◽  
Cytochrome Oxidase Activity ◽  
Lateral Geniculate ◽  
Areas 17 And 18 ◽  
C Complex ◽  
Dorsal Lateral Geniculate

AbstractThe purpose of the present study was to assess changes in the levels of cytochrome oxidase (CO) activity in the dorsal lateral geniculate nucleus (dLGN) of the adult cat following removal of primary visual cortical areas 17 and 18 on the day of birth (P1), P28, or in adulthood (≫6 months). Cytochrome oxidase activity was measured in histological sections 9 or more months after the cortical ablation. Control measures obtained from intact cats show that CO activity is normally highest in the A-laminae of dLGN, and slightly lower in the C-complex. Following visual cortex ablations incurred at any age, CO activity levels are reduced in the A-laminae. This reduction is most profound following ablations incurred on P28 or in adulthood. In contrast, CO activity in the C-complex of dLGN is at nearly normal levels following ablations on P1 or P28, but not in adulthood. These findings contribute to our understanding of the role played by the dLGN in the transfer of visual signals along retino-geniculo-extrastriate pathways that expand following early removal of areas 17 and 18. Moreover, they have implications for our understanding of spared behavioral functions attributed to the extrastriate cortex in cats which incurred early damage of areas 17 and 18.

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