摘要:

AbstractWe have used light and electron microscopic immunocytochemical techniques to study the distribution and morphology of neurons that contain vasoactive intestinal polypeptide‐like immunoreactivity (VIP‐Ir) in the adult rat striatum. VIP‐Ir cells were sparsely distributed throughout all rostrocaudal levels of the striatum. Cell bodies were of medium size (12–17 m̈m) and gave rise to three to five primary dendrites, which branched close to the soma and became varicose. These dendrites appeared aspiny at the light microscope level and could be traced up to 250 m̈m in length. Dendrites frequently traversed axonal bundles in the striatum, a pattern not exhibited by neurons containing somatostatin‐like or substance P‐like immunoreactivity. In several instances, very fine varicose processes arborized extensively within 40 m̈m of the VIP‐Ir soma; these may represent axons. In thin‐sectioned preparations, examined under the electron microscope, the nucleus of VIP‐Ir neurons was eccentrically located and showed several deep invaginations. Immunoreactive dendrites of VIP‐Ir cells appeared virtually spine‐free. Synapses with asymmetric or symmetric junctional specializations were present on the dendritic surface. Several VIP‐Ir varicosities were found to terminate on the VIP‐Ir cell body, forming synaptic junctions with symmetric specializations; these synapses may derive from recurrent collaterals. VIP‐Ir cells thus resemble other aspiny striatal neurons considered like

ISSN:0092-7317    

DOI:10.1002/cne.902560102

出版商:Alan R. Liss, Inc.    

年代:1987

数据来源: WILEY

摘要:

AbstractThe callosal connections within the posterior parietal and occipital cortices were studied in the squirrel monkey with horseradish peroxidase tracing techniques. The data were evaluated with particular emphasis on the relationship of major callosal connections along the 17–18 border. The overall pattern of callosal connections in the squirrel monkey also was compared with callosal patterns in other New World simians. Our results show that the dense band of callosal connections along the 17–18 border in the squirrel monkey differs from the connections observed in other New World monkeys in that it is virtually confined to area 18 and avoids area 17. In addition to a continuous band of callosal connections in area 18 that parallels the 17–18 border, rostral extensions of the band are oriented perpendicular to the 17–18 border and present an obvious periodicity. The remaining parieto‐occipital cortex contains a complex pattern of callosal connections that is strikingly similar to patterns reported for other New World monkeys. Thus, it is likely that the dorsolateral extrastriate visual cortex in the squirrel monkey is organized in a manner similar to that found within other New Worl

ISSN:0092-7317    

DOI:10.1002/cne.902560103

出版商:Alan R. Liss, Inc.    

年代:1987

数据来源: WILEY

摘要:

AbstractBoth anatomical and physiological mapping methods have revealed that the mammalian cerebellar cortex consists of a family of parasagittal bands of cells, each band with its own pattern of afferent and efferent axons. Monoclonal antibody mabQ113 recognizes an unknown polypeptide antigen that is confined to a subset of rat cerebellar Purkinje cells. Immunoreactive cells are arranged into parasagittal bands extending throughout the vermis and hemispheres. Expression of the Q113 epitope by individual Purkinje cells may not be all‐or‐nothing, since the bands tend to be more strongly stained in the vermis than the hemispheres. The band display is symmetrical about the midline and reproducible from individual to individual. Wholemount immunocytochemistry and serial reconstruction reveal a median band of mabQ113+ Purkinje cells adjacent to the midline (P1 + ) and six other positive bands disposed symmetrically at either side (P2+ to P7 + ). Bands are distinct throughout most of the cortex but tend to fuse ventrally and caudally. There are two sources of interindividual differences. Firstly, most animals express supernumerary “satellite” bands in the vermis. Satellite bands are usually only one cell wide, are not bilaterally symmetrical, and differ in position and number from individual to individual. Secondly, the precise position of an individual band can differ, perhaps according to the variable cortical lobulation, for example, the position of P4+ in lobules VIII/IX and P6+ in lobule VII. While a scheme of parasagittal bands is a good description of the vermian organization, the distribution of mabQ113+ and mabQ113‐ Purkinje cells in the hemispheres may be better described as a checkerboard of antigeni

ISSN:0092-7317    

DOI:10.1002/cne.902560104

出版商:Alan R. Liss, Inc.    

年代:1987

数据来源: WILEY

摘要:

AbstractHippocampal neurons containing GABA‐, cholecystokinin(CCK)‐, vasoactive intestinal polypeptide(VIP)‐, or somatostatin(SS)‐like immunoreactivity (LI) were localized in sections of rat hippocampus. GABA‐, CCK‐, VIP, and SS‐LI are found exclusively in interneurons of the area dentata and hippocampus. In the area dentata, GABA‐LI occurs in cells of all strata but predominates in type 1 and 2 basket cells. CCK‐LI is present in a subset of these basket cells and some hilar cells. VIP‐LI is present in a distinct subset of dentate interneurons that, unlike the type 1 and 2 basket cells, do not contribute to the fiber plexus in the inner molecular layer. These VIP‐LI interneurons send their axons to nearby granule cells and form a plexus in the hilus. SS‐LI, although rare in cells of the molecular and granular layers, is present in a large population of hilar interneurons that do not exhibit GABA‐, CCK‐, or VIP‐LI. In area CA3 of the hippocampus, a variety of morphologically diverse interneurons containing GABA‐, CCK‐, VIP‐, or SS‐LI are present in all strata. In area CA1, SS‐LI is present mainly in cells of strata oriens and pyramidale. GABA‐CCK‐ and VIP‐LI interneurons are present in all strata of CA1 but, unlike the SS‐LI cells, are most numerous in strata pyramidale and radiatum. These findings in the area dentata, taken together with those of Kosaka et al. (J. Comp. Neurol. 239:967–969, '85), indicate that two main populations of interneurons can be discriminated on the basis of the substances they contain. One is a group of GABA‐LI cells, some of which also contain CCK‐ and/or VIP‐LI. These cells innervate the granule cells and the second group of interneurons, the SS‐LI hilar cells, which apparently form part of the

ISSN:0092-7317    

DOI:10.1002/cne.902560105

出版商:Alan R. Liss, Inc.    

年代:1987

数据来源: WILEY

摘要:

AbstractThe size, location, distribution, and spatial orientation of the chandelier cell of the human visual cortex are described for the first time. The rapid Golgi method has been utilized to study the structural features of these inhibitory interneurons. The human chandelier cell is a small stellate interneuron with prominent idiodendritic and idioaxonic arborizations. These arborizations are distributed within a narrow rectangular tissue slab that measures approximately 300 × 200 × 100 m̈m. This relatively small and narrow functional territory is oriented perpendicular to the pial surface and to the long axis of the gyrus. The territory of distribution of its axon is larger than and encloses that of its dendrites. The number of specific axonic terminals (candles) per chandelier cell is also relatively small, ranging from 60 to 80 units. These axonic terminals represent the functional units of the neuron and reflect the number of pyramidal cell axons contacted by it. The chandelier cell of the human visual cortex possibly represents the smallest neuron of this kind described to date. The size of its functional territory and the number of its specific axonic terminals are among the smallest of any neuron of this kind thus far described. It is postulated herein that in the course of mammalian phylogeny the chandelier cell shows a tendency toward a progressive reduction in the size of its functional territory and in the number of its functional units (candles), as well as a tendency toward a more “idio” pattern of distribution for its axonic and dendritic arborizations. Perhaps, these progressive evolutionary modifications could reflect a tendency of this type of interneuron toward an increasing specialization. The possible existence of a relationship between the progressive transformation of the chandelier cell and the increasing visual acuity, dexterity, and skillfulness in the course of mammalian phylogeny should be ex

ISSN:0092-7317    

DOI:10.1002/cne.902560106

出版商:Alan R. Liss, Inc.    

年代:1987

数据来源: WILEY

摘要:

AbstractThe morphology and laminar distribution of individual optic fibers projecting to the lateral geniculate nucleus (GL) ofGalagoandTupaiawere studied following iontophoretic injections of horseradish peroxidase (HRP) into the optic tract. InGalagothe GL is composed of three functionally matched pairs of layers, each characterized by cells of a given size, one large, one medium‐sized, and one small. The results show that there is a close correspondence between the size of the afferent fibers and the size of the neurons in the target layer: large axons project to the magnocellular layers, medium‐sized axons project to the parvicellular layers, and small fibers project to the intercalated layers. InTupaiathe GL is composed of two functionally matched pairs and two unmatched layers. Optic fibers that project to the medial matched pair (1 and 2) are only slightly larger than those that project to the lateral matched pair (4 and 5), but both are larger than those that project to the unmatched layers (3 and 6).In both species terminal arbors and the distribution of terminal boutons within layers corresponded closely with the organization of dendritic processes of cells in the target layer. This correspondence was particularly evident in the parvicellular layers inGalagoand in layer 6 inTupaia: parvicellular terminal arbors, like the dendrites of parvicellular cells, are organized in narrow columns oriented along lines of projection, whereas layer 6 terminal arbors, like the dendrites of layer 6 cells, are oriented in elongated strips perpendicular to lines of projection. In both species there was evidence for sublaminar terminations in some layers. These were restricted to the parvicellular layers inGalagoand layers 4 and 5 inTupaia.With the exception of a small number of fine fibers in the intercalated layers inGalago, optic fibers in both species terminated in one and only one layer in a set. The significance of this result depends on the relation between ganglion cell classes and what is being segregated in different GL layers. Lateral geniculate lamination varies even in closely related species and has evolved independently in such distantly related lines as carnivores and primates. It is not surprising, therefore, that what is being segregated varies from species to spec

ISSN:0092-7317    

DOI:10.1002/cne.902560107

出版商:Alan R. Liss, Inc.    

年代:1987

数据来源: WILEY

摘要:

AbstractTemporopolar cortex (TP) can be subdivided into agranular, dysgranular, and granular components. The telencephalic input into the temporopolar cortex arises from the orbitofrontal and medial frontal regions, modality‐specific visual and auditory association areas, paralimbic regions, the piriform olfactory cortex, the hippocampus, the amygdala, the claustrum, and the basal forebrain.Afferents from limbic and paralimbic regions are directed mostly to the agranular and dysgranular sectors of the temporal pole, whereas afferents from isocortical association areas are distributed predominantly within the granular sector.The temporopolar cortex provides a site for the potential convergence of sensory and limbic inputs. Auditory inputs predominate in the dorsolateral part of the temporopolar cortex whereas visual inputs become prominent only in the ventral portions of this region. Olfactory inputs are directed mostly to the medial parts of the temporal pole. These medial parts also receive more extensive projections from the amygdaloid nucle

ISSN:0092-7317    

DOI:10.1002/cne.902560108

出版商:Alan R. Liss, Inc.    

年代:1987

数据来源: WILEY

摘要:

AbstractThe area postrema in goldfish is a dorsal midline structure in the caudal medulla spanning the level of the obex. As in other vertebrates, the sinus capillaries of the area postrema in goldfish are fenestrated. In goldfish, however, the area postrema is organized in a unique laminar fashion; from superficial to deep: meninx, vasculature, palisade layer, cell body layer, and ventral neuropil layer.Virtually all of the neurons of the area postrema exhibit tyrosine hydroxylase‐like immunoreactivity. Each immunoreactive neuron is essentially bipolar, with a short apical dendrite extending dorsally to reach the external basal lamina of the capillaries and a basal dendrite reaching into the subjacent layer of neuropil. The apical dendrites have no synaptic specializations and probably function as interoceptors detecting blood‐borne chemicals that leak out of the fenestrated capillaries. The basal dendrites receive synaptic input both within the neuropil of the area postrema and in the commissural nucleus of Cajal into which they extend. Primary afferent fibers of the subdiaphragmatic branches of the vagus nerve terminate within the area postrema and commissural nucleus. Thus the neurons of the area postrema may serve not only as direct chemoreceptive interoceptors but may also receive input from other visceral afferent syst

ISSN:0092-7317    

DOI:10.1002/cne.902560109

出版商:Alan R. Liss, Inc.    

年代:1987

数据来源: WILEY

摘要:

AbstractCharacterization of serotonin‐containing neurons in the glossiphoniid leechHaementeria ghilianiiwas undertaken to provide a reference for developmental studies of their differentiation and for comparative studies of their distribution and function. Five types of serotonin‐containing neurons were identified with an antiserum against serotonin and by radioenzymatic assay of individual isolated somata. They contain high concentrations of serotonin (in some cases exceeding saturation in aqueous solution) and their serotonin content increases with growth of the animal. Each type is capable of taking serotonin up from the extracellular fluid, as demonstrated autoradiographically. They exhibit segment‐specific, and on comparison with hirudinid leeches, species‐specific, differences in distribution, morphology, and the expression of serotonin met

ISSN:0092-7317    

DOI:10.1002/cne.902560110

出版商:Alan R. Liss, Inc.    

年代:1987

数据来源: WILEY

摘要:

AbstractA visual cortex lesion made in adult cats leads to a loss of direction selectivity and a loss of response to the ipsilateral eye among cells in posteromedial lateral suprasylvian (PMLS) cortex of cats. However, a visual cortex lesion made in young cats results in normal direction selectivity and normal ocular dominance in PMLS cortex. Thus cats with an early lesion demonstrate functional compensation in PMLS cortex. The present experiment determined whether the functional compensation depends upon an intact corpus callosum.Cats received a unilateral visual cortex lesion on the day of birth (day 1) or at 8 weeks of age. When the cats were adult, the corpus callosum was sectioned and 24 hours later recordings were made in PMLS cortex ipsilateral to the visual cortex lesion. Results were compared to cats with a similar lesion and an intact corpus callosum.In cats with a lesion made on day 1, a corpus callosum section did not affect receptive‐field properties or ocular dominance in PMLS cortex. Therefore, functional compensation is not dependent on input via the corpus callosum in these animals. However, in cats with a lesion made at 8 weeks, a corpus callosum section resulted in a decrease in the percentage of direction‐selective cells and in the percentage of cells driven by the ipsilateral eye. Despite the decrease, the percentage of direction‐selective cells still was greater than in cats with an adult unilateral visual cortex lesion. Thus, while partly dependent on callosal inputs, some functional compensation for direction selectivity remains on the basis of ipsilateral inputs. In contrast, the percentage of cells driven by the ipsilateral eye was no longer significantly different from that in cats with an adult visual cortex lesion. This suggests that functional compensation for response to the ipsilateral eye is dependent on an intact corpus callosum in cats that received a visual cortex lesion at 8 weeks o

ISSN:0092-7317    

DOI:10.1002/cne.902560111

出版商:Alan R. Liss, Inc.    

年代:1987

数据来源: WILEY