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J Repérant

Publications and source records attributed to J Repérant.

At least 109 records · Page 6Linked to original sources
PubMed1983

Long term regeneration of contralateral and induced ipsilateral retinal projections to the remaining optic tectum of Rutilus rutilus.

The regeneration of optic tract fibers hs been investigated in Rutilus kept at 18-20 degrees C, 6-7 months after ablation of one optic tectum and simultaneous section of the optic nerve from the contralateral eye. The labeling of the optic fibers obtained following injection of either tritiated proline or HRP in either of the eyes showed the existence of a normal contralateral retino-tectal projection to strata opticum, fibrosum et griseum superficial (SFGS), griseum centrale, and album centrale. Furthermore, it demonstrated the presence of a conspicuous newly-formed ipsilateral retino-tectal projection to both superficial and deep layers of SFGS in the form of horizontal bands. The partial overlapping of ipsi- and contralateral projections in SFGS was confirmed by a double-labeling technique (HRP and tritiated proline). The results suggest a retinal hyperinnervation of the remaining optic tectum.

Animals↗
PubMed1983

[Structures of telencephalic projection in the pigeon. Identification by marking with horseradish peroxidase].

The sites of origin of afferents to the telencephalon in the pigeon were investigated using the HRP technique (TMB). Following large multiple injections of the enzyme into the cerebral hemisphere, peroxidase-positive neurons were identified at diencephalic levels: ipsilaterally in DLM, DMA, DLP, DIP, DMP, Rt, Ov, SRt and SCE/SCI; bilaterally in DLA and SPC. At mesencephalic and posterior brainstem levels, HRP-labeled neurons were found: ipsilaterally in AVT, ZpNIII, ICo, FRM, FRL, TP and SCv; bilaterally in GCt, ZpFLM, neurons were found: ipsilaterally in AVT, ZpNIII, ICo, FRM, FRL, TP and SCv; bilaterally in GCt, ZpFLM, Annul, LoC, LC and PrV. Smaller injections of HRP into different regions of the telencephalon demonstrated, for some of the latter structures, either single or multiple projections upon topographically distinct subdivisions.

Afferent Pathways↗
PubMed1983

A light and electron microscope study of the basal optic system in the reptile Vipera aspis.

The basal optic system of the reptile Vipera aspis was investigated under both light and electron microscopy. The basal optic root (BOR), mainly composed of large diameter myelinated fibers (congruent to 2 micrometers) terminates in he nucleus of the basal optic root (nBOR). The different histological techniques employed disclose a neuronal population distributed in the following three categories: 1) small neurons, of low proportion (21%), have cytological features which allow their classification as Golgi type II neurons, 2) medium-sized neurons (35%) and 3) large multipolar neurons (44%). Both of the latter types of neurons are contacted by optic terminals. Neuroglial elements, astrocytes, oligodendrocytes, and microgliacytes were observed either in an intermediate fascicular or perineuronal satellite position. The neuropil of nBOR is made up of both axonal and dendritic profiles. The dendrites which contain synaptic vesicles (DCSVs) are not numerous (15% of the total population of profiles containing synaptic vesicles, PCSVs) and have the peculiarity of participating in serial and triadic arrangements within glomerulus-like structures where they are postsynaptic to optic terminals. Six types of axon terminals have been identified. Those containing a more or less spheroidal synaptic vesicle population are subdivided in two classes: S 1, the optic terminals being the most numerous (48,5% of the total PCSVs) and S 2 (19% of the total PCSVs). On the basis of density of flattened synaptic vesicles, F type terminals are classified either as F 1 (9%) or F 2 (8%), the first being more densely packed with synaptic vesicles. A very low proportion of terminals (0,5%) comprises a mixed population of large granular vesicles (G) associated with rounded or ellipsoidal synaptic vesicles. Occasionally, gap junctions are observed between an axon terminal and a dendritic profile. The present results show a similarity of synaptic circuitry when compared to bird and mammal nBOR.

Animals↗
PubMed1982

The retinofugal pathways in a primitive actinopterygian, the chondrostean Acipenser güldenstädti. An experimental study using degeneration, radioautographic and HRP methods.

Experimental study of the retinofugal pathways in Acipenser güldenstädti was carried out on 109 specimens using 3 experimental tracing methods: Fink-Heimer (after retinal ablation), radioautography (after intraocular injection of tritiated markers) and HRP (after intraocular injection of HRP or iontophoretic deposit of HRP on the optic nerve). The optic fiber was found to partially decussate at the chiasm and to project to 5 contralateral regions: (1) hypothalamus (area optica hypothalami); (2) thalamus (area optica dorsalis thalami, area optica mediale thalami, nucleus thalamicus tractus optici marginalis, nucleus laminaris ventralis); (3) pretectum (nucleus pretectalis ventralis, nucleus commissurae posterioris, nucleus intercalaris lateralis); (4) optic tectum (superficial layers); and (5) mesencephalic tegmentum (area optica accessoria). The ipsilateral component was well developed and innervated the same regions mentioned above. A few contralateral optic fibers crossed again in the posterior commissure and terminated within ipsilateral visual pretectal structures. Although the architecture of the visual centers was less elaborated in this paleopterygian than in neopterygians (holosteans, teleosteans), we observed that the general organization of the retinal contralateral projections in this fish was comparable to that of more advanced actinopterygians. Our results indicate that this pattern was probably set at a very early date, perhaps as soon as the emergence of the chondrostean grade at the beginning of the Devonian.

Animals↗
PubMed1982

Thalamo-hyperstriatal projections in the pigeon (Columbia livia) as demonstrated by retrograde double-labeling with fluorescent tracers.

Thalamo-hyperstriatal projections were studied in the pigeon by retrograde thalamic labeling following bilateral injections of different combinations of fluorescent substances (Fast Blue, Evans Blue, Nuclear Yellow) into the hyperstriatum. The distribution of single and double-labeled neurons within the thalamic nuclei dorsolateralis anterior and superficialis parvocellularis indicated the presence of distinct functional sub-regions containing neuronal populations providing ascending projections which were either ipsilateral, contralateral or bilateral via collateral axon branching.

Animals↗
PubMed1981

The retinofugal pathways in the primitive African bony fish Polypterus senegalus (Cuvier, 1829).

Retinal projections were studied using Fink-Heimer and radioautographic methods in Polypterus senegalus, a species which is representative of a small group of African fresh-water bony fish often considered to be very primitive. The large optic nerve showed partial decussation at the chiasm. Two major contralateral tracts were observed: the axillary and marginal optic tracts, with the latter being subdivided posteriorly into the tractus opticus medialis and tractus opticus lateralis. The retina projected onto the: (1) hypothalamus (area optica postoptica); (2) thalamus (nucleus opticus dorsolateralis thalimi, nucleus dorsomedialis thalami, corpus geniculatum laterale, area optica dorsolateralis thalami, area optica ventrolateralis thalami); (3) pretectum (nuclei commissurae posterioris, pretectalis ventralis, pretectalis dorsalis); and (4) optic tectum (stratum marginale, stratum opticum, stratum griseum et fibrosum superficiale, stratum griseum et album centrale, stratum griseum et fibrosum periventriculare). Ipsilateral retinal projections were demonstrated to the same 4 levels and more precisely to the nucleus opticus dorsolateralis thalami, area optica dorsolaterale thalami, nucleus commissurae posterioris, stratum marginale and stratum griseum et album centrale. The existence of a retinal projection to the mesencephalic tegmentum is discussed. Comparing the primary optic system of Polypterus with that of other jawed vertebrates, and particularly with that of other bony fish, indicated that this species possesses a combination of characteristics which are both actinopterygian and sarcopterygian. The phylogenetic significance of this mozaic anatomical arrangement is discussed.

Animals↗
PubMed1981

Fine structure of the superficial layers of the viper optic tectum. A Golgi and electron-microscopic study.

The superficial layers of the viper optic tectum, which receive fibers from he retina, were studied using both light and electron microscopes. The optic fibers layer, or stratum opticum, is composed of 200 to 250 tight fascicles containing thin fibers, nearly all of which are myelinated. The main optic terminal layers, the stratum griseum et fibrosum superficiale, the greatest part of the cellular population is composed of small vertically oriented neurons and horizontal nerve cells, many of which are probably local circuit neurons. The neuropil of the stratum griseum et fibrosum superficiale is made up of small nerve elements, including three types of profiles containing synaptic vesicles; 1) boutons with pleiomorphic synaptic vesicles (P), representing over 47% of the total population of profiles containing synaptic vesicles and comprising three subgroups (P1, P2, and P3); 2) boutons with spheroidal synaptic vesicles (S), forming more than 29% of the total populations of profiles containing synaptic vesicles and comprising two categories, S1 and S2 (S2, the more numerous, represents the optic boutons, which make up 22% of the total populations of profiles containing synaptic vesicles); and 3) dendrites with pleiomorphic vesicles, accounting for approximately 23% of the total populations of profiles containing synaptic vesicles. A study of synaptic patterns revealed a large number of serial synapses and a lesser number of triplets or triadic synapses. The presynaptic components are boutons containing spheroidal (S1, S2) or pleiomorphic (P1, P2, P3) synaptic vesicles. The intermediate profile was always a dendrite with synaptic vesicles which frequently belonged to the small neurons of the stratum griseum et fibrosum superficiale. Comparison of the present results with other recent data shows that the synaptic circuitry in the optic tectum of Vipera aspis closely resembles the pattern observed in the optic tectum of other vertebrates, ranging form fish to mammals. However, quantitative differences exist, especially with regard to the proportion of dendrites containing synaptic vesicles. Their number seems to be higher in sauropsidians than in mammals, particularly in primates.

Animals↗
PubMed1980

Radioautographic evidence for both orthograde and retrograde axonal transport of labeled compounds after intraocular injection of [3H]proline in the lamprey (Lampetra fluviatilis).

[3H] Proline injected intraocularly in lampreys has been shown to be bidirectionally transported: 24--96 h after the injection, retinofugal fibers and terminals as well as nerve cell bodies at the origin of the retinopetal system were intensely labeled. These results are at variance with the generally held belief that [3H]proline is taken up only by cell bodies and transported by the anterograde flow. The significance of the retrograde axonal transport of [3H]proline in the lamprey retinopetal system is discussed.

Animals↗
PubMed1980

Orthograde and retrograde axonal movement of label and transneuronal transport phenomena after intraocular injection of [3H]adenosine in a poikolotherm vertebrate (Vipera aspis).

The axoplasmic transport of [3H]adenosine (or its related compounds) has been examined radioautographically in the visual system of a poïkilotherm species (Vipera aspis) following an intraocular injection of the nucleoside. It has been found that the axonal transport of the label occurs both in the anterograde directions. Furthermore, a considerable labelling of neuronal bodies as a result of transneuronal transport of tritiated material from the optic endings has been observed, particularly in the primary optic centers. Transneuronal labelling, however, appears less intense than retrograde cell labelling.

Adenosine↗
PubMed1980

[Anatomical study of the afferent pathways of the rostral telencephalon in the Gallus domesticus chick].

The neuroanatomical method involving retrograde axonal transport of horseradish peroxidase (HRP) was employed in the chick Gallus domesticus to investigate ascending projection systems to the rostral telencephalon. Following either extensive or restricted injections of the enzyme into different regions of the latter, differential bilateral or unilateral projections onto the Wulst (hyperstriatum accessorium, hyperstriatum intercalatus superior, hyperstriatum dorsale) were demonstrated from the dorsal thalami complex (nucleus dorsolateralis anterior thalami, pars lateralis). Other nuclei of the dorsal thalamus shown to project to the rostral telencephalon were nuclei, dorsolateralis medialis, dorsolateralis posterior, dorsomedialis anterior, parvocellularis and rotundus. At the level of the mesencephalon, rostral telencephalic projections were found to originate in the substantia grisea centralis, the strata cellulare externum and internum, the lateral reticular formation and the area ventralis. More caudally peroxidase label was localized in the nuclei locus, ceruleus, subceruleus dorsale, subceruleus ventrale and within the principal Vth nucleus. The results obtained using restricted injections of HRP made it possible to more precisely identify the telencephalic projections sites of several of the above areas and nuclei. The data is compared to previous findings regarding ascending projection system in different avian species and some methodological problems in the use of HRP technique are discussed.

Afferent Pathways↗
PubMed1979

[Radioautographic analysis of retinofugal projections in the primitive bony fish Polypterus senegalus C].

Retinofugal pathways of Polypterus senegalus C. have been examined by means of the radioautographic method. Contralaterally the retina projects to the hypothalamus, thalamus, pretectum and tectum. An important ipsilateral component has been observed. No retinal projection to the mesencephalic tegmentum has been identified. Comparing the primary optic system of Polypterus with that of other body Fish, indicates that this species possesses a combination of characteristics which are both actinopterygian and sarcopterygian. The significance of this mozaic arrangement is discussed.

Animals↗
PubMed1978

[Primary visual centers in the frog (Rana esculenta L.) and the problem of ipsilateral projections. Radioautographic study].

The topographic organization of the frog's primary visual system has been reexamined in Rana esculenta using autoradiographic technique. 10 to 24 hrs following an intraocular injection of tritiated proline, an intense labelling was observed contralaterally in the various retinal projection centres (preoptic area); neuropils of Bellonci; corpus geniculatum of the thalamus; posterior thalamus; posterodorsal preoptic area; magnocellular pretectal nucleus and basal optic nucleus; tectal laminae A to G of Potter), as already described. Furthermore, the presence of a ipsilateral projection within the hypothalamus (preoptic area), the thalamus (neuropils of Bellonci and corpus geniculatum) and the pretectium (posterior thalami neuropil, pretectal optic area) is confirmed. On the other hand, the existence of ipsilateral retinotectal (to Potter's lamina F) and retino-tegmentomescencephalic projections (to the basal optic nucleus), which were thusfar questioned, has been demonstrated.

Animals↗
PubMed1978

A radioautographic study of retinal projections in type I and type II lizards.

The retinofugal projections of 5 species (Acanthodactylus boskianus, Scincus scincus, Tarentola mauritanica, Uromastix acanthinurus and Zonosaurus ornatus) belonging to 5 different families of Type I and Type II lizards have been examined by means of the radioautographic method. In the 5 species the retinal ganglion cells project to the contralateral hypothalamus (nucleus suprachiasmaticus), thalamus (nucleus geniculatus lateralis pars ventralis, nucleus geniculatus lateralis pars dorsalis), pretectum (nuclei lentiformis mesencephali, geniculatus pretectalis, postero-dorsalis griseus tectalis), tectum opticum (layer 2 to layer 6 of the stratum griseum et fibrosum superficiale) and tegmentum mesencephali (nucleus opticus tegmenti). Ipsilateral optic fibers were never observed in Uromastix acanthinurus, whereas an uncrossed quota was visible in both nucleus geniculatus lateralis pars dorsalis and nucleus postero-dorsalis in the other species. An ipsilateral retinotectal projection was observed only in Tarentola mauritanica. With the exception of the nucleus griseus tectalis the contralateral optic centers identified in this material have to a large extent been observed in other reptiles belonging to the different orders. The presence in reptiles of a general pattern of contralateral visual projections indicates that these were established very clearly in the course of evolution. Similarities become apparent when this plan is compared with that observed in birds. In marked contrast the ipsilateral component in reptiles is unstable and mutable in nature. This ipsilateral retinotectal projections do not appear to be a feature restricted to Type I lizards. On the other hand, the presence of this optic component cannot be linked solely to nocturnal habits.

Animals↗
PubMed1978

A light and electron microscopic study of the nucleus isthmo-opticus in the pigeon.

A morphological study of the nucleus isthmo-opticus (NIO) has been carried out using several histological approaches as well as electron microscopic analysis. The nucleus is composed of bipolar cells of relatively constant size. The neurones within a given nuclear region are oriented in the same plane and direction. EM observations show that neighbouring cells often give off complex spinous extensions that come in close contact with each other. The apposed membranes of these extensions display large attachment plaques. The neuropil contains relatively abundantly myelinated axons, thin dendrites, and various types of terminals. A majority of the terminals contain rounded vesicles. The tecto-isthmic projection has been studied electronmicroscopically, by using the degeneration technique. The tecto-isthmic terminals contain predominantly rounded vesicles. They almost always make axo-dendritic contacts. Degeneration and autoradiographic techniques at the light microscope level fully confirm previous data by others on the topologic organization of the projection. The above two techniques were applied to the study of NIO-retinal interrelationships. No retinal projection to NIO could be confirmed. On the other hand, enucleation induces a terminal degeneration of slow time course. This finding suggests the presence of intrinsic fibre collaterals of isthmo-retinal axons. The existence of fibre projections from the oculomotor nuclei is shown by a light microscope degeneration study. Fibres coming from the trochlear nucleus might correspond to collaterals of motor axons.

Animals↗