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.

Regeneration of an abnormal ipsilateral visuotectal projection in Xenopus is delayed by the presence of optic fibres from the other eye

Development ◽  
1980 ◽  
Vol 57 (1) ◽  
pp. 129-141
Author(s):  
Charles Straznicky ◽  
David Tay ◽  
John Glastonbury
Keyword(s):  
Optic Nerve ◽  
The Other ◽  
Nerve Section ◽  
Eye Enucleation ◽  
Contralateral Projection ◽  
Electrophysiological Findings ◽  
Optic Fibre ◽  
Tectal Neurons ◽  
The Right ◽  
Early Regeneration

Optic fibre regeneration was studied by [3H]proline autoradiography and by mapping electrophysiologically the direct visuotectal projections to thecontralateral and ipsilateral tecta 12–16 weeks after sectioning the right optic nerve in Xenopus two to four weeks after metamorphosis. The experiments were carried out in three groups: (A) optic nerve section in newly metamorphosed animals withembryonic left-eye enucleation; (B) optic nerve section with simultaneous left-eye enucleation; and (C) optic nerve section with delayed left-eye enucleation 5–31 days prior to sacrifice. In all but three animals regenerated optic fibres were demonstrated morphologically both in the contralateral and ipsilateral tecta. The contralateral visuotectal projectionwas fully restored within the 12–16 weeks in all animals. In animals with embryonic enucleation or in those where the enucleation was carried out simultaneously with optic nerve section, a direct ipsilateral visuotectal projection was established at the same time as the restoration of the contralateral projection. In contrast, no direct ipsilateral visuotectal projection was detectable in the presence of optic fibres from the other eye in the doubly innervated tecta. However, 14–31 days after the removal of the incumbent optic fibres by left-eye enucleation a direct visuotectal projection from the right eye to the ipsilateral tectum was established, and its polarity corresponded to the normal contralateral retinotectal projection. The apparent disparity between morphological and electrophysiological findings in the doubly innervated tectum suggests that superimposed optic fibres are unable to form normal synaptic relations with tectal neurons during early regeneration, delaying the establishment of the induced direct ipsilateral visuotectal projection.

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.

Optic nerve transection decreases 2-[125I]iodomelatonin binding in the chick optic tectum

1992 ◽  
Vol 590 (1-2) ◽  
pp. 325-328 ◽  
Author(s):  
Diana N. Krause ◽  
Judith A. Siuciak ◽  
Margarita L. Dubocovich
Keyword(s):  
Optic Nerve ◽  
Optic Tectum ◽  
Nerve Transection ◽  
Optic Nerve Transection

Comparative strengths and weaknesses of peroxidase and colloidal gold in pre- and post-embedding immunolabeling techniques

1987 ◽  
Vol 45 ◽  
pp. 1002-1005
Author(s):  
D. R. Abrahamson ◽  
P. L. St.John ◽  
E. W. Perry
Keyword(s):  
Electron Microscopy ◽  
Horseradish Peroxidase ◽  
Light Microscopy ◽  
Colloidal Gold ◽  
Light Microscope ◽  
Ultrastructural Localization ◽  
The Other ◽  
Quantitative Studies ◽  
Dense Suspension ◽  
Antigen Localization

Antibodies coupled to tracers for electron microscopy have been instrumental in the ultrastructural localization of antigens within cells and tissues. Among the most popular tracers are horseradish peroxidase (HRP), an enzyme that yields an osmiophilic reaction product, and colloidal gold, an electron dense suspension of particles. Some advantages of IgG-HRP conjugates are that they are readily synthesized, relatively small, and the immunolabeling obtained in a given experiment can be evaluated in the light microscope. In contrast, colloidal gold conjugates are available in different size ranges and multiple labeling as well as quantitative studies can therefore be undertaken through particle counting. On the other hand, gold conjugates are generally larger than those of HRP but usually can not be visualized with light microscopy. Concern has been raised, however, that HRP reaction product, which is exquisitely sensitive when generated properly, may in some cases distribute to sites distant from the original binding of the conjugate and therefore result in spurious antigen localization.

Relief of facial pain after combined removal of precentral and postcentral cortex

1971 ◽  
Vol 34 (4) ◽  
pp. 537-543 ◽  
Author(s):  
Richard A. Lende ◽  
Wolff M. Kirsch ◽  
Ralph Druckman
Keyword(s):  
Facial Pain ◽  
The Other ◽  
Precentral Gyrus ◽  
Nerve Section ◽  
Content Type ◽  
Burning Pain ◽  
Cortical Localization ◽  
The Brain ◽  
Fine Print ◽  
Frontal Lobotomy

✓ Cortical removals which included precentral and postcentral facial representations resulted in relief of facial pain in two patients. Because of known failures following only postcentral (SmI) ablations, these operations were designed to eliminate also the cutaneous afferent projection to the precentral gyrus (MsI) and the second somatic sensory area (SmII). In one case burning pain developed after a stroke involving the brain stem and was not improved by total fifth nerve section; prompt relief followed corticectomy and lasted until death from heart disease 20 months later. In the other case persistent steady pain that developed after fifth rhizotomy for trigeminal neuralgia proved refractory to frontal lobotomy; relief after corticectomy was immediate and has lasted 14 months. Cortical localization was established by stimulation under local anesthesia. Each removal extended up to the border of the arm representation and down to the upper border of the insula. Such a resection necessarily included SmII, and in one case responses presumably from SmII were obtained before removal. The suggestions of Biemond (1956) and Poggio and Mountcastle (1960) that SmII might be concerned with pain sensibility may be pertinent in these cases.

The retinotectal projections after uncrossing the optic chiasma in Xenopus with one compound eye

Development ◽  
1971 ◽  
Vol 26 (3) ◽  
pp. 523-542
Author(s):  
K. Straznicky ◽  
R. M. Gaze ◽  
M. J. Keating
Keyword(s):  
Compound Eye ◽  
The Other ◽  
Cell Type ◽  
Cell Type Specificity ◽  
Optic Chiasma ◽  
Normal Side ◽  
Cell Specificity ◽  
Normal Projection ◽  
Retinotectal Projections ◽  
Fixed Cell

The nature of the retinotectal projection from a compound (NN or TT) eye in Xenopus raises certain problems concerning the mode of formation of connexions between the eye and the tectum. Each half of the compound eye appears to spread its connexions across the entire extent of the (apparently normal) contralateral tectum. This could indicate a certain plasticity in the way in which optic fibres can connect with the tectum. Alternatively, it is conceivable that each (similar) half of the compound eye is only able to innervate its corresponding half-tectum; in which case the uninnervated half-tectum could remain undeveloped and the innervated half-tectum could overgrow to resemble a normal tectum. This mechanism would preserve the idea of a rigidly fixed cell-to-cell specificity between retina and tectum. In an attempt to distinguish between these two mechanisms (spreading or overgrown half-tectum) we have given each of a series of Xenopus embryos at stage 32 one compound eye (NN or TT). Then, shortly after metamorphosis, we uncrossed the optic chiasma and 6 months later recorded the retinotectal projections from each eye to the tecta. Thus by connecting up the normal eye to the suspect tectum, and the compound eye to the normal tectum, we used the normal side in each case to provide an indication of the degree of abnormality with which the other side was connected. The results showed that a compound eye (NN or TT), connected to a normal tectum, gave a typical reduplicated map across the entire tectum, whereas the normal eye, when connected to the tectum which was previously innervated by the compound eye, gave an approximately normal projection across the whole of that tectum. These results lead us to conclude that, in the Xenopus visual system, no strict cell-to-cell type specificity exists; rather, what is preserved throughout these experimental manoeuvres is the polarity and extent of the projection.

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