Retinal projections in quail (Coturnix coturnix)

1989 ◽  
Vol 3 (4) ◽  
pp. 377-387 ◽  
Author(s):  
Robert B. Norren ◽  
Rae Silver
Keyword(s):  
Optic Nerve ◽  
Horseradish Peroxidase ◽  
Optic Tectum ◽  
Lateral Part ◽  
Retinal Projections ◽  
Coturnix Coturnix ◽  
Intraocular Injection ◽  
Anterior Thalamus ◽  
Ventrolateral Thalamus ◽  
Pretectal Area

AbstractThe trajectory of retinal projections and the location of retinorecipient nuclei in the quail brain was examined after application of horseradish peroxidase (HRP) either to the cut end of the optic nerve or following intraocular injection of HRP. Retinal projections to the hypothalamus, dorsalateral anterior thalamus (rostralateral part, magnocellular part, and lateral part), lateral anterior thalamus, lateroventral geniculate nucleus, lateral geniculate intercalated nuclei (rostral and caudal parts), ventrolateral thalamus, superficial synencephalic nucleus, external nucleus, tectal gray, diffuse pretectal area, pretectal optic area, ectomammillary nucleus, and optic tectum were revealed. Retinal projections observed in quail were compared with results obtained in other avian species and considered in relation to possible anatomic pathways underlying photoperiodism and circadian rhythms.

The discontinuous visual projections on the Xenopus optic tectum following regeneration after unilateral nerve section

Development ◽  
1986 ◽  
Vol 94 (1) ◽  
pp. 121-137
Author(s):  
D. J. Willshaw ◽  
R. M. Gaze
Keyword(s):  
Optic Nerve ◽  
Horseradish Peroxidase ◽  
Optic Tectum ◽  
Small Proportion ◽  
The Other ◽  
Nerve Transection ◽  
Nerve Section ◽  
Retinotectal Projections ◽  
Uniform Background ◽  
Whole Mounts

The establishment of retinotectal projections following transection of one optic nerve in developing Xenopus has been investigated. Between 3 weeks and 11 months after the operation, the nerve fibre tracer horseradish peroxidase (HRP) was applied to either the operated or the unoperated nerve, and the brains were prepared for examination as whole mounts. In most cases fibres from the operated nerve innervated both tecta, with the result that one tectum was doubly innervated and one tectum singly innervated. Two months after transection of the optic nerve in tadpole life, between stages 50 and 54, this nerve usually made a uniform projection on the contralateral tectum and a striped projection on the ipsilateral, doubly innervated, tectum. The projection made by the unoperated nerve on this tectum was a similar pattern of stripes, which ran generally rostrocaudally. Two months after transection of the optic nerve of newly metamorphosed animals, the projection formed by the operated nerve on the doubly innervated tectum was usually a pattern of spots or spots mixed together with stripes in no particular orientation superimposed on a roughly uniform background. In a small number of cases the projections made by the same nerve on the two tecta were approximately complementary; that is, the presence of label on one tectum corresponded with its absence on the other tectum. The results are examined in the context of the development of the retina and of the tectum. It is suggested that the consistently oriented stripes which result from nerve transection at a stage at which only a small proportion of the retinal fibres had reached the tectum are formed by the interaction of two equally matched sets of developing fibres, stripe orientation being determined by the mode of growth of the optic tectum. The formation of patterns of spots or spots mixed together with stripes following nerve transection after the end of the main phase of tectal histogenesis, and when 50 % of the optic fibres had already reached the tectum, is attributed to an unequal competition between the two sets of fibres.

The Central Nervous Control of Colour Change in the Minnow (Phoxinus Phoxinus L.)

1971 ◽  
Vol 54 (1) ◽  
pp. 83-91
Author(s):  
MICHAEL J. GENTLE
Keyword(s):  
Optic Nerve ◽  
Optic Tectum ◽  
Posterior Part ◽  
Colour Change ◽  
Complete Removal ◽  
The Other ◽  
Nervous Control ◽  
Phoxinus Phoxinus ◽  
External Conditions

1. The colour of the minnow Phoxinus phoxinus L. and its ability to undergo colour change were studied after partial and complete blinding. The blinding was accomplished either by section of the optic nerve or by tectal ablation. 2. Following bilateral section of the optic nerve the blinded minnows darken. After the initial darkening, half of the fish pale and the other half remain dark. 3. The colour of the fish blinded by bilateral section of the optic nerve could not be affected by external conditions. 4. Following complete removal of the optic tectum the fish at first paled, but after 24 h they darkened to very variable tints. 5. Unilateral section of the optic nerve coupled with unilateral tectal removal on the same or opposite side did not affect the ability of the fish to change colour. 6. The bilateral removal of the anterior tectum from a blinded darkened fish did not affect its colour. 7. The bilateral removal of the posterior tectum of a darkened fish caused maximal pallor. 8. By a series of lesions an area in the dorsal posterior part of the optic tectum was found to cause darkening in the blinded fish because following its removal the fish paled. 9. It is suggested that the fibres from the tectum may act by exciting or inhibiting the neurones of the paling centre in the anterior medulla.

scholarly journals Thalamic-Medial Temporal Lobe Connectivity Underpins Familiarity Memory

2020 ◽  
Vol 30 (6) ◽  
pp. 3827-3837 ◽  
Author(s):  
Alex Kafkas ◽  
Andrew R Mayes ◽  
Daniela Montaldi
Keyword(s):  
Temporal Lobe ◽  
Medial Temporal Lobe ◽  
Critical Role ◽  
Dynamic Interaction ◽  
Thalamic Nuclei ◽  
Neural Basis ◽  
General Role ◽  
Anterior Thalamus ◽  
Ventrolateral Thalamus ◽  
Familiarity And Recollection

Abstract The neural basis of memory is highly distributed, but the thalamus is known to play a particularly critical role. However, exactly how the different thalamic nuclei contribute to different kinds of memory is unclear. Moreover, whether thalamic connectivity with the medial temporal lobe (MTL), arguably the most fundamental memory structure, is critical for memory remains unknown. We explore these questions using an fMRI recognition memory paradigm that taps familiarity and recollection (i.e., the two types of memory that support recognition) for objects, faces, and scenes. We show that the mediodorsal thalamus (MDt) plays a material-general role in familiarity, while the anterior thalamus plays a material-general role in recollection. Material-specific regions were found for scene familiarity (ventral posteromedial and pulvinar thalamic nuclei) and face familiarity (left ventrolateral thalamus). Critically, increased functional connectivity between the MDt and the parahippocampal (PHC) and perirhinal cortices (PRC) of the MTL underpinned increases in reported familiarity confidence. These findings suggest that familiarity signals are generated through the dynamic interaction of functionally connected MTL-thalamic structures.

The Optic Chiasm of Australian Marsupials

1995 ◽  
Vol 43 (5) ◽  
pp. 467
Author(s):  
AM Harman
Keyword(s):  
Nervous System ◽  
Optic Nerve ◽  
Central Region ◽  
Optic Tract ◽  
Optic Chiasm ◽  
Lateral Part ◽  
Guidance Cues ◽  
Optic Axons ◽  
The Brain

The optic chiasm of mammals is the region of the nervous system in which optic axons have a choice of route, either they enter the optic tract on the same side of the brain or they cross the chiasm and enter the opposite optic tract. in eutherian (placental) mammals, axons approach the midline of the chiasm and then either continue across the chiasm or turn back to enter the tract on the same side of the brain. The midline of the chiasm provides guidance cues that repel uncrossed but not crossed axons. However, it has recently been shown that in a marsupial, the quokka wallaby, axons destined to stay on the same side of the brain remain in the lateral part of the optic nerve and chiasm and never approach the midline. The structure of the chiasm reflects this partitioning of axons with different routes by having a tripartite structure. The two lateral regions contain only uncrossed axons in rostral chiasmatic regions and the central region contains only crossed axons. Therefore, axons passing through the chiasm of this species must use guidance cues that differ from those of eutherian mammals. Here I show that the chiasms of species of both diprotodont and polyprotodont Australian marsupials have a similar tripartite structure and that uncrossed axons are confined to lateral regions. It seems likely, therefore, that the chiasm of marsupials has fundamental differences in structure and optic axon trajectory compared with that of eutherian mammals studied to date.

Effect of light on the labeling of optic tectum gangliosides after an intraocular injection of N-[3H]acetylmannosamine

1979 ◽  
Vol 86 (3) ◽  
pp. 849-854 ◽  
Author(s):  
Beatriz L. Caputto ◽  
Alicia H.R. Maccioni ◽  
Carlos A. Landa ◽  
Ranwel Caputto
Keyword(s):  
Optic Tectum ◽  
Intraocular Injection ◽  
Effect Of Light

Development of the nucleus isthmi in Xenopus, II: Branching patterns of contralaterally projecting isthmotectal axons during maturation of binocular maps

1989 ◽  
Vol 2 (2) ◽  
pp. 153-163 ◽  
Author(s):  
Susan B. Udin
Keyword(s):  
Optic Nerve ◽  
Horseradish Peroxidase ◽  
Visual Cues ◽  
Visual Fields ◽  
Physiological Data ◽  
Nucleus Isthmi ◽  
Anterograde Transport ◽  
Branching Patterns ◽  
Juvenile Stages ◽  
Contralateral Eye

AbstractThe tectum of Xenopus frogs receives input from both eyes. The contralateral eye's projection reaches the tectum directly, via the optic nerve, and the ipsilateral eye's projection reaches the tectum indirectly, via the nucleus isthmi. Under normal conditions, the topography of the ipsilateral map relayed from the nucleus isthmi is in register with the topography of the retinotectal map from the contralateral eye. During development, the process of aligning the two maps is complicated by the dramatic changes in binocular overlap of the two eyes' visual fields which take place during late tadpole and juvenile stages. The goal of this study is to determine the branching patterns of contralaterally projecting isthmotectal axons before, during, and after the period of rapid eye migration.Isthmotectal axons were filled by anterograde transport of horseradish peroxidase (HRP) from the nucleus isthmi. The results show that crossed isthmotectal axons enter the entire extent of the tectum before binocular overlap begins to increase. Therefore, binocular overlap is not necessary for the initial isthmotectal projection to span the tectum. The density of isthmotectal branches rises dramatically at the same time that the eyes begin to shift. During the period when eye migration is most rapid, many isthmotectal axons form arbors which resemble adult arbors but which extend over greater proportions of the tectal surface.The axons appear to be directed toward appropriate mediolateral positions as they enter the tectum. Their trajectories are roughly rostocaudal, with relatively little change along the mediolateral dimension. These data, when combined with available physiological data, suggest that mediolateral order is initially established by vision-independent mechanisms but can be altered by vision-dependent mechanisms. Rostrocaudal order becomes discernable only at the time when binocular visual cues become available and appears to be established primarily on the basis of the activity of the retinotectal and isthmotectal axons.

Sign in / Sign up

Export Citation Format

Share Document