摘要:

AbstractRetinal ganglion cells were studied in pigmented ferrets that received small electrophoretic injections of horseradish peroxidase (HRP) into the dorsal lateral geniculate nucleus (LGNd) or optic tract. Ferret retina contains a number of types of retinal ganglion cells of which the relative cell body sizes, dendritic field structures, and central projections correspond closely to those of retinal ganglion cell types in the cat. Ferret retina contains about the same proportion of alphalike cells, a lower proportion of betalike cells, and thus a high proportion of other types of ganglion cells than cat retina. Ferret retina has a visual streak and somewhat weaker area centralis than cat retina. Changes in ganglion cell morphology associated with eccentricity are less pronounced in the ferret than in the cat. The adult ferret retina is about 12.5 mm in diameter, and the nasotemporal division is about 2.7 mm from the temporal margin. Interestingly, virtually all alpha cells in the pigmented ferrets studied projected contralaterally. Studies of infant ferrets indicate that 4 days after birth (P4) the area of ferret retina is 25% that of the adult. The neonatal ferret retina contains numerous small, densely packed cells in the presumptive ganglion cell layer. At P4 these cells appear to be uniformly distributed across the retina. The area centralis and visual streak are not obvious as late as 8 days after birth.

ISSN:0092-7317    

DOI:10.1002/cne.902410102

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

年代:1985

数据来源: WILEY

摘要:

AbstractThe catecholaminergic innervation of the human septal area and closely related structures has been visualized by using tyrosine hydroxylase (TH) and dopamine‐β‐hydroxylase (DBH) as immunocytochemical markers. TH‐like immunoreactivity with no corresponding DBH labelling was considered to be indicative of dopaminergic fibers.Catecholaminergic innervation offered the following similarities to that of rodents: (1) moderate innervation in the medial septal division, with predominant DBH immunolabelling; (2) dense dopaminergic innervation in the lateral septal nuclei, organized in a laminar pattern; (3) presence of dopaminergic pericellular arrangements in the dorsal septum and bed n. of the stria terminalis; (4) clustering of dopaminergic terminals in n. accumbens associated with a medioventral zone of DBH‐like immunoreactive fibers; (5) close overlap between dopaminergic fields and acetylcholinesterase‐reactive zones in both the lateral septum and the n. of the stria terminalis.Differences with the catecholaminergic septal innervation of rodents consisted of (1) general caudal extension of the dopaminergic fields, possibly accounted for by the vertical stretching and caudal displacement of the septal nuclei in man; (2) complementary lateromedial. topography of dopaminergic and DBH‐immunoreactive inputs in the n. of the stria terminalis as opposed to their dorsoventral organization in rodents; (3) presence of TH‐immunolabelled cell group in the anterior olfactory nucleus and parolfactory cortex, which seems specific for primates.Precise topographical mapping of the catecholaminergic structures in this central region of the limbic forebrain seems to be a prerequisite for accurate tissue sampling in the biochemical investigations of pathological cases and should help in the interpretation of aminergic dysfunction in a variety of

ISSN:0092-7317    

DOI:10.1002/cne.902410103

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

年代:1985

数据来源: WILEY

摘要:

AbstractThe selectivity previously reported for retrograde labeling patterns obtained following D‐[3H]‐aspartate injections and proposed to be related to the transmitter specificity of the labeled pathways was tested in afferents to the superior colliculus (SC) of rats and rabbits.In rats selectivity was assessed by comparing retrograde perikaryal labeling patterns observed in D‐[3H]‐aspartate experiments with those found after administration of a nonselective tracer, horseradish‐peroxidase‐labeled wheat germ agglutinin (HRP‐WGA), and of the tritiated neurotrasmitter γ‐aminobutyric acid (GABA). Following D‐[3H]‐aspartate injections into the SC labeling was intense in a large number of cortical and hypothalamic neurons. Other afferents to the SC, however, such as those originating from the ventrolateral geniculate nucleus, the pars reticulata of the substantia nigra, the locus coeruleus, the pontine nuclei, or the retinal ganglion cells, were not labeled. Similar results were obtained in rabbits.In cats, the analysis was focused on the cerebral cortex, since in an earlier investigation no retrograde labeling had been detectedin the visual cortex following D‐[3H]‐aspartate injectionsin the SC. In the present work, however, retrogradely labeled neuronswere observed in various cortical areas including a few in visual cortex.This report shows selective retrograde labeling for a part of the afferents to the SC. This selectivity does not display major differences among the mammalian species studied. Moreover, according to the information available about the distribution of neurotransmittersin the brain, the findings reported here favour the idea that D‐[3H]‐aspartate is a retrograde tracer selective for glutamatergic a

ISSN:0092-7317    

DOI:10.1002/cne.902410104

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

年代:1985

数据来源: WILEY

摘要:

AbstractThe development of cerebellar external granule cells in rats was studied from the time of demarcation of the cerebellar anlage on embryonal day 12 up to the time of their disappearance on postnatal day 20. Two types of cells were found. The first was orientated tangentially to the cerebellar surface and was characterized by a persistent contact to the basal lamina via an external process, with a lamellopodial tip and a cytoskeleton characteristic for migratory cells, and a retracting internal process featuring a single cilium. This cell type was the first to appear on embryonal day 14 in the caudolateral angle of the cerebellar anlage and, later, spread, over the whole cerebellar surface. It disappeared after the external granular layer was completely expanded over the cerebellum. The second cell type appeared for the first time on embryonal day 16 in the caudal part of the cerebellar anlage and disappeared on postnatal day 20. It was orientated radially and also had contact with the basal lamina either with its cell body or with one or two short, radial processes, whose morphology differed from that of the external process of tangential cells by the absence of a lamellopodium and a prominent cytoskeleton. After postnatal day 17 contacts of external granule cells with the basal lamina decreased rapidly in length and number and were absent on postnatal day 20.We interpret these findings to indicate that tangential external granule cells are migrating before taking on a radial orientation characteristic for the mitotic cycle of proliferating external granule cells. In the light of increasing evidence implicating extracellular matrix in various developmental events of the nervous system we propose that the basal lamina of the cerebellum may be used as substrate and guidance structure by migrating external granule cells, and, furthermore, that the persistent contact with the basal lamina may mediate stimuli maintaining external granule cells in a proliferative state.

ISSN:0092-7317    

DOI:10.1002/cne.902410105

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

年代:1985

数据来源: WILEY

摘要:

AbstractIn this study the motor, prefrontal, and somatosensory areas of the sheep cerebral cortex were defined on the basis of their thalamic afferents traced with the horseradish peroxidase method.The motor area (areas 4 and 6) occupies the cruciate gyrus. It receives a substantial projection from the thalamic nuclei ventralis anterior, ventralis lateralis, medialis dorsalis, and centralis lateralis and a smaller one from the nuclei ventralis medialis, centralis medialis, paracentralis, lateralis dorsalis, lateralis posterior, centromedianus, parafascicularis, suprageniculatus, ventralis posterolateralis, and the midline nuclei. Area 4 receives afferents mainly from the nuclei ventralis anterior, ventralis lateralis, medialis dorsalis, and lateralis posterior, whereas area 6 receives afferents mainly from the nuclei ventralis anterior, medialis dorsalis, and lateralis posterior and fewer afferents from the nucleus ventralis medialis.The prefrontal area occupies the gyrus proreus and receives numerous afferents from the nucleus medialis dorsalis and fewer from the nuclei lateralis posterior and ventralis medialis.The area extending between the lateral fissure, the coronal sulcus, the presylvian sulcus, and the rostral branch of the lateral fissure is connected mainly with sensory thalamic nuclei. Thalamic afferents were found to emanate from the nuclei ventralis posteromedialis (its parvicellular part included), ventralis posterolateralis, ventralis medialis, paracentralis, lateralis posterior, medialis dorsalis, centromedianus, suprageniculatus, paraventricularis, the substantia nigra, and the ventral part of the lateral geniculate nucleus. The first somatosensory area (Johnson et al., '74, J. Comp. Neurol. 158:81–108) was found to extend between the coronal, the diagonal, and the anterior suprasylvian sulci and to receive afferents almost exclusively from the nucleus ventralis posteromediali

ISSN:0092-7317    

DOI:10.1002/cne.902410106

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

年代:1985

数据来源: WILEY

摘要:

AbstractThe neocortical origins of the anterior commissure in the acallosal, marsupial opossum were studied with the horseradish peroxidase (HRP) method. Following complete surgical transection of the anterior commissure, HRP was applied directly to the cut fiber tips. This procedure resulted in very large numbers of vividly labeled cells within the neocortex. The labeled cells were plotted and counted for comparison among cytoarchitectonic areas and among cortical layers. For comparative purposes, the neocortical origins of the corpus callosum are studied with the same procedure in the rat.No cytoarchitectonic area was entirely devoid of labeled cells in either species. The concentration of labeled cells throughout the entire neocortex averaged 25.2 cells/0.05 mm3in opossum and 31.2 cells/0.05 mm3in rat. The concentrations of labeled cells were correlated for the eight cytoarchitectonic areas common to the two species, though they were different enough in number to be statistically reliable. The distribution of labeled cells both among and within cytoarchitectonic areas was often more homogeneous in opossum than in rat.Although cortical layer 1 had no labeled cells in either species, the distribution of labeled cells across the remaining cortical layers differed sharply between the two species. In opossum, layer 3 had the most labeled cells (averaging 55% of the total number) while layer 5 had considerably less (averaging 12%). In rat, layer 5 had as many labeled cells as layer 3–both layers averaging 43% of the total number of labeled cells.In both species, striate cortex deviated markedly from other cytoarchitectonic areas. Although both species had very few labeled cells in striate cortex, those that were labeled were invariably supragranular in opossum and infragranular in rat.The similarities and dissimilarities in the topographic distribution of the origins of the two types of interhemispheric fiber systems seem to parallel the degree of cortical (and thalamic) differentiation in the two animals. However, the differences in laminar distribution are much greater and in particular, the small contribution of layer 5 in opossum as opposed to rat may well be functionally significan

ISSN:0092-7317    

DOI:10.1002/cne.902410107

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

年代:1985

数据来源: WILEY

摘要:

AbstractWe present an HRP study of the sensory tracts and motor nuclei associated with feeding (especially use of the tongue) in plethodontid salamanders (mainlyBatrachoseps attenuatus, Bolitoglossa subpalmata, Desmognathus ochrophaeus, Eurycea bislineata, andPlethodon jordani). The nerves studied are VII (ramus hyomandibularis only), IX, X, XI, the first spinal nerve (hypoglossus), and the second spinal nerve. Two types of sensory projections are universally found in the brainstem: superficial somatosensory projections of VII, IX, and X, and deeper visceral sensory projections of IX and X to the fasciculus solitarius. The first spinal nerve and the spinal accessory nerve (XI) have no sensory projections, but the second spinal nerve has typical projections along the dorsal funiculus of the spinal cord.The motor nuclei of VII ramus hyomandibularis, IX, and X form a combined nucleus situated at the level of the IX/X root complex. The nucleus of the first spinal nerve is well separated from the combined nucleus and is situated rostral and caudal to the obex. The rostral part of the motor nucleus of the second spinal modestly overlaps that of the first. The motor nucleus of the spinal accessory nerve is more or less restricted to the region of the second spinal nerve. Its fibers leave the brain through the last root of the IX/X complex and the related ganglion. Bolitoglossine and nonbolitoglossine differ in the architecture of the spinal nuclei. Two distinct types of motor neurons occur in spinal nuclei of nonbolitoglossine species–some of those with tongue projection–but only one type is found amongthe tongue‐projecting bolitoglossine

ISSN:0092-7317    

DOI:10.1002/cne.902410108

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

年代:1985

数据来源: WILEY

ISSN:0092-7317    

DOI:10.1002/cne.902410101

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

年代:1985

数据来源: WILEY