摘要:

AbstractThe newt brain represents a simplified model for the increasingly complex vertebrate neuronal organization. The localization of neuropeptide Y‐like (NPY‐like) containing neurons in the brain ofTriturus cristatuswas studied by means of indirect immunofluorescence, peroxidase‐antiperoxidase, and avidin‐biotin techniques using a highly specific antiserum. NPY‐like positive cell bodies were observed in several areas, most notably in the telencephalon (primordium hippocampi and amygdaloid complex), the preoptic and suprachiasmatic areas, the hypothalamus, the dorsal thalamus, the tegmentum, and the rhombencephalon (laterolateral grey column and raphe area). Nerve fibres were particularly abundant in the pallium, striatum, septum, amygdaloid, preoptic neuropils, and pars intercalaris diencephali. Bundles of NPY‐immunoreactive fibres also were visualized in the dorsal thalamus and in the posterior hypothalamus. The pars intermedia lacked any NPY‐like positive fibres. Neuronal processes also were found in the tectum mesencephali and in the body of the cerebellum. A prominent NPY‐like fibre network was observed in the octavolateralis. Concentrations of NPY measured by means of a specific radioimmunoassay were threefold higher in the hypothalamus (15.2 ± 1.3 ng/mg proteins) than in the rhombencephalon (4.9 ± 0.3) and the mesencephalon (4.3 ± 0.2). The concentration found in the telencephalon was 2.1 ± 0.3 ng/mg proteins. Sephadex G‐50 gel chromatography of whole brain extracts indicated the presence of high molecular weight forms of NPY‐like material in addition to the authentic peptide. Both amphibian and mammalian NPY peptides had an apparent molecular weight of 4,000 daltons, as evidenced by immunoblotting analysis. High‐performance liquid chromatography demonstrated, however, that the newt peptide was slightly less hydrophobic than porcine NPY. The present findings indicate that NPY‐immunoreactive neurons are widely distributed in the brain of urodeles. Our data indicate that the NPY molecule has been relatively well

ISSN:0092-7317    

DOI:10.1002/cne.902750302

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

摘要:

AbstractThe representation of the visual field in the second visual area (V2) was reconstructed from multiunit visual responses and anatomical tracers. Receptive field plotting was performed during multiple recording sessions in sevenCebus apellamonkeys under N2O/O2and immobilized with pancuronium bromide. V2 forms a continuous belt of variable width around striate cortex (V1) except at the most anterior portion of the calcarine sulcus. In each hemisphere V2 contains a visuotopic representation of the contralateral visual hemifield. The representation of the vertical meridian is adjacent to that of V1 and forms the posterior border of V2. The representation of the fovea of V2 is adjacent to that of V1. The representation of the horizontal meridian (HM) is continuous with that of V1; then it splits to form the anterior border of V2, both dorsally and ventrally. The lower quadrant of the visual field is represented dorsally and the upper quadrant ventrally. The visual topography of V2 is coarser than that of V1. In V2, receptive fields corresponding to recording sites separated by a cortical distance of up to 4 mm may represent the same portion of the visual field.In three additional animals, combined injections of fluorescent tracers along the HM representation in V1 yielded two projection sites at the anterior border of V2. The split of the HM representation is estimated to occur at an eccentricity below 1°.Quantitative analysis showed that in V2 the representation of the central visual field is magnified relative to that of the periphery. The cortical magnification factor is greater along the isopolar dimension than along the isoeccentric one. Receptive field size in V2 increases with increasing eccentricity.In sections stained for myelin by the Heidenhein‐Wöelcke method V2 can be distinguished from the surrounding cortex for most of its ext

ISSN:0092-7317    

DOI:10.1002/cne.902750303

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

摘要:

AbstractShort‐survival, sequential, and long‐survival thymidine radiograms of rat embryos, fetuses and young pups were analyzed in order to delineate the boundaries of the proliferative thalamic neuroepithelium, describe its early transformations, identify its regional divisions, and, finally, attempt to relate its distinct neuroepithelial components to specific thalamic nuclei that they supply with neurons. On day E13 the thalamic neuroepithelium consists of two divisions, the rostral lobe and the caudal lobe, and interposed between the two is a small transient structure, the reticular protuberance. By day E14 the rostral lobe has become partitioned into the anterior lobule and the reticular lobule, and the caudal lobe into the intermediate lobule and the posterior lobule. By day E15 these four lobules have become further partitioned into sublobules, characterized as regional eversions and inversions (concavities and convexities) of the thalamic neuroepithelium. Several of these sublobules are still recognizable on day E16 but progressively disappear thereafter.In this introductory paper, some evidence is presented in support of the hypothesis that the identified thalamic sublobules represent putative cell lines committed to produce neurons for specific, early‐generated thalamic nuclei. Detailed documentation of the evidence on which the identifications are based is provided in subsequent papers of this series which deal with the early development of specific thalamic regions and nuclei. In our attempt to identify these putative cell lines, we sought to meet the following criteria: (1) a good match between the time course of mitotic activity in a neuroepithelial sublobule and the birth days of neurons in the nucleus that it is postulated to supply with neurons, (2) relative proximity between the putative neuroepithelial source and the thalamic target structure, and, where possible, (3) the tracing of migrating cells from the germinal source to its destination. Using these criteria we have made the following tentative identifications. The early derivatives of the anterior thalamic lobules are the sublobules (committed cell lines) of the anterior thalamic nuclei, and of the central lateral and mediodorsal nuclei. The early derivatives of the reticular lobule and reticular protuberance are the sublobules of the reticular nuclear complex. The early derivatives of the intermediate lobule are the sublobules of the ventrolateral and ventrobasal nuclei. Finally, the early derivatives of the posterior lobule are the sublobules of the dorsal geniculate, ventral geniculate, and medial geniculate nuclei. The proposed partitioning and mosaic organization of the thalamic neuroepithelium are discussed with reference to traditional descrip

ISSN:0092-7317    

DOI:10.1002/cne.902750304

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

摘要:

AbstractShort‐survival, sequential, and long‐survival thymidine radiograms of rat embryos, fetuses, and young pups were analyzed in order to examine the time of origin, settling pattern, and neuroepithelial site of origin of the anterior thalamic nuclei–the lateral dorsal (lateral anterior), anterodorsal, anteroventral and anteromedial nuclei–and of two rostral midline structures–the anterior paraventricular and paratenial nuclei. The neurons of the lateral dorsal nucleus are generated over a 3‐day period between days E14‐E16 and their settling pattern displays a combined lateral‐to‐medial and dorsal‐to‐ventral neurogenetic gradient. The bulk of the neurons of the anteroventral nucleus are generated over a 3‐day period between days E15‐E17 and settle with an oblique lateral‐to‐medial and ventral‐to‐dorsal neurogenetic gradient. The bulk of the neurons of the anteromedial nucleus are generated over a 2‐day period between days E16‐E17 and show the same settling pattern as the anteroventral nucleus. The neurons of the anterodorsal nucleus are generated over a 3‐day period between days E15‐E17 and show a lateral‐to‐medial neurogenetic gradient. The bulk of the neurons of the central part and lateral part of the paraventricular nucleus are generated over a 2‐day period (E16‐E17 and E17‐E18, respectively) and each part displays a ventral‐to‐dorsal neurogenetic gradient. Finally, the bulk of the neurons of the paratenial nucleus are generated over a 4‐day period between days E15‐E18 and settle with a lateral‐to‐medial neurogenetic gradient.Observations are presented that the anterior thalamic nuclei, constituting the distinct “limbic thalamus,” derive from a discrete neuroepithelial source. This is the crescent‐shaped germinal matrix lining the diencephalic (medial) wall of the hitherto unrecognized anterior transitional promontory, which we call the anterior thalamic neuroepithelial lobule. On day E16 three migratory streams leave the anterior neuroepithelial lobule and, on the basis of their labeling pattern in relation to the neurogenetic gradients of the anterior thalamic nuclei, they are identified, from dorsal to ventral, as the putative migratory streams of the anterodorsal, anteroventral, and lateral dorsal nuclei. On day E17 the putative migratory stream of the anteromedial nucleus appears to leave the same neuroepithelial region that on the previous days was the source of the anteroventral nucleus. Dorsally, two neuroepithelial patches persist after day E17 and these are identified as the puta

ISSN:0092-7317    

DOI:10.1002/cne.902750305

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

摘要:

AbstractShort‐survival, sequential, and long‐survival thymidine radiograms of rat embryos, fetuses, and young pups were analyzed in order to examine the time of origin, settling pattern, migratory route, and site of origin of neurons of the reticular nuclear complex of the thalamus. On the basis of its chronoarchitectonics, the reticular nucleus was divided into a central, medial, and lateral subnucleus. The central subnucleus is the earliest produced component of the entire thalamus with over 50% of its neurons being generated on day E13 and another 40% on day E14. Peak production of neurons of the lateral and medial subnuclei is on day E14. There is a lateral (earlier) to medial (later) neurogenetic gradient between these two components of the reticular complex: only about 12% of the lateral subnucleus neurons, but close to 30% of the medial subnucleus neurons, are generated on day E15. Because the lateral and medial subnuclei display the typical outside‐in gradient found in the thalamus, they are considered to constitute a single cytogenetic sector; the early generated central subnucleus, which violates this order, is considered to constitute a separate cytogenetic sector.Observations are presented that neurons of the central reticular subnucleus originate in a unique neuroepithelial region, the reticular protuberance. The migration of heavily labeled cells was traced from this region in rats labeled with3H‐thymidine on day E13 and killed on the subsequent days. The neurons of the lateral and medial reticular subnuclei originate in the reticular lobule of the thalamic neuroepithelium. The migration of heavily labeled, spindle‐shaped cells was traced from this region in rats labeled with3H‐thymidine on days E14 and E15 and killed at daily intervals thereafter. The neurogenetic gradient of the reticula thalamic complex seen in postnatal rats is established b

ISSN:0092-7317    

DOI:10.1002/cne.902750306

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

摘要:

AbstractThe distribution of serotoninergic neurons in the nervous system of the scale wormHarmothoe imbricatawas visualized in the anterior half of the body by the peroxidase‐antiperoxidase (PAP) immunohistochemical method with a specific antiserotonin antibody. Immunoreactive neuronal somata were localized in discrete ganglion cell masses of the dorsally situated cerebral ganglion and in segmental ganglia of the ventral nerve cord. They also make up the majority of neurons present in the parapodial ganglia. Large and small varicose fibers stained in the neuropile of all the above‐mentioned ganglia but also in interganglionic connectives and segmental nerves. On the basis of soma size and location and of fiber distribution, the reactive neurons were identified as primarily interneuronal with a few motoneurons and presumptive afferent neurons. The presence of a motor component was substantiated by observations of several reactive varicose fibers spread over longitudinal muscle layers of the trunk. In addition, neurites of the subepidermal nerve plexus and enterochromaffinlike cells of the gut epithelium reacted with the serotonin antibody. It is concluded that serotoninergic pathways are ubiquitous elements in the organization of the central and peripheral nervous system of this polychaete. The significance of these findings in relation to other annelid groups and to the physiological role of serotonin is discus

ISSN:0092-7317    

DOI:10.1002/cne.902750307

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

摘要:

AbstractThe distribution of single and/or double‐labeled neurons in the cerebellar nuclei was investigated in a prosimian primate (Galago) by means of fast blue (FB) and nuclear yellow (NY) as retrograde tracers. Injections were made into spatially separate regions of cerebellar cortex on one side (zones C1−C3in lobules IV and V and in the paramedian lobule) and into the same zones of lobules IV and V on both sides. Following unilateral injections single‐ and double‐labeled somata were seen in the anterior (NIA) and posterior (NIP) interposed cerebellar nuclei on the same side. Single‐labeled cells were, in general, more concentrated in NIA from the lobule IV‐V injection and in NIP from the PML placement; double‐labeled somata were about evenly distributed between NIA and NIP. Cell labeling was sparse in the contralateral NIP. Large and small somata were filled with FB, NY, or FB+NY ipsilateral to the injection sites while the majority of labeled neurons on the contralateral side had small oval‐ or fusiform‐shaped somata. Subsequent to bilateral injections cells labeled with each tracer were concentrated in the NIA, moderate in number in the NIP, both on the ipsilateral side, and sparse in the contralateral NIP.The double labeling of cells in the present study indicates that these neurons project to spatially separated, yet possibly functionally related, areas of ipsilateral cortex. Since larger and small somata were double labeled it is possible that those cells with cerebellofugal processes to extracerebellar targets may simultaneously relay information to divergent cortical sites. In contrast, the few labeled cells seen in the contralateral NIP have small oval and fusiform somata. These neurons may be specifically involved in cerebelloolivary and olivocerebell

ISSN:0092-7317    

DOI:10.1002/cne.902750308

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

摘要:

AbstractNeuropeptide Y‐like immunoreactivity has been localized previously within three classes of amacrine cells in the turtle retina. We have used the avidin‐biotin with horseradish peroxidase technique to label these neurons for examination at the ultrastructural level to answer the following questions. Where are the synaptic contacts of these neurons made? What types of neurons are involved pre‐ and postsynaptically? What is the intracellular distribution of the immunoreactivity?Processes with neuropeptide Y‐like immunoreactivity were located primarily within three regions of the inner plexiform layer: stratum 1, stratum 3, and at the border between strata 4 and 5. In all three regions the processes with neuropeptide Y‐like immunoreactivity received synaptic contacts from both unlabeled amacrine and bipolar cells, but the majority of the synaptic input in all three regions was from unlabeled amacrine cells. Processes with neuropeptide Y‐like immunoreactivity were presynaptic to unlabeled amacrine cells in all three regions, but also formed contacts onto unlabeled bipolar cells in the region between strata 4 and 5.The immunoreactivity within these cells gave rise to a diffuse reaction product that was distributed throughout the cytoplasm and within large vesicles. This localization of neuropeptide Y‐like immunoreactivity within large vesicles suggests that this peptide may play a neuromodulatory role. Such a role would be consistent with previous studies of neuropeptides in the

ISSN:0092-7317    

DOI:10.1002/cne.902750309

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

摘要:

AbstractThe anatomy of the sympathetic pathways from the spinal cord to the lumbar sympathetic trunk and the inferior mesenteric ganglion was studied systematically in the rat. Details of the arrangements of white and gray rami communicantes, sympathetic trunk ganglia, the intermesenteric nerve, and the lumbar splanchnic nerves are summarized. A modified nomenclature for the segmental ganglia of the paravertebral sympathetic chain is proposed.Cell bodies of sensory and sympathetic axons projecting to the skin and skeletal muscle of the rat hindlimb were labeled retrogradely with horseradish peroxidase (HRP) in order to study numbers, segmental distribution, and location of the somata of these neurons quantitatively. HRP was applied to the nerves supplying skeletal muscle (gastrocnemius‐soleus, GS), hairy skin (sural, SU; saphenous, SA) and to a mixed nerve (tibial, TI). All sensory somata and 96.4% of the sympathetic cell bodies were located ipsilaterally. Sensory somata were commonly restricted to two adjacent dorsal root ganglia (usually L3‐4 for SA; L4‐5 for GS, TI; L5‐6 for SU). Although the sympathetic somata were more widely distributed rostrocaudally (four to six segments), their maximum was always located one or two segments more cranially than the sensory outflow, i.e., corresponding to the rami communicantes grisei.From the data, it is estimated that 420 sympathetic and 530 afferent neurons project into GS, 590 and 3,610 into SU, 920 and 3,750 into SA, and 1,070 and 5,760 into TI. These absolute neuron numbers are compared with electron microscopic fiber counts from the lit

ISSN:0092-7317    

DOI:10.1002/cne.902750310

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

ISSN:0092-7317    

DOI:10.1002/cne.902750301

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY