摘要:

AbstractThe distribution of avian pancreatic polypeptide‐like (APP) immuno‐reactivity within the rat hypothalamus was investigated with the indirect immunoperoxidase method. APP immun ore active perikarya are found in largest numbers in the retrochiasmatic area, the arcuate nucleus, and the supracommissural portion of the interstitial nucleus of the stria terminalis. Small clusters of immunoreactive neurons are also consistently observed in the ventral aspect of the medial preoptic area and lateral hypothalamic area, immediately dorsolateral to the optic chiasm and tracts. These neurons are apparent in all animals but are more intensely stained and occur in larger numbers following colchicinepretreatment. Other immunoreactive neurons are visible only in colchicine‐treated rats and are scattered throughout the anterior and lateral hypothalamic areas and the supramammillary nucleus. Immunoreactive axons and terminal fields present an extensive and highly characteristic distribution throughout the hypothalamus, which in many instances exhibits differential distribution within specific subfields of hypo‐thalamic nuclei and areas. The heaviest concentrations of APP immuno‐reactive axons are present in the periventricular nucleus throughout the ros‐trocaudal extent of the hypothalamus, the ventrolateral portion of the suprachiasmatic nucleus, the retrochiasmatic area, the parvocellular para‐ventricularnucleus, the ventral supraopticnucleus, theperifornical nucleus, the ventral dorsomedial nucleus, and the arcuate nucleus. Moderate plexuses of immunoreactive fibers are also present in the medial preoptic area, the anterior and lateral hypothalamic areas, the nucleus circularis, the median eminence, and the ventral premammillary area. Other areas, such as the ventromedial nucleus, contain virtually no immunoreactive axons but are encapsulated by a dense plexus of immunoreactive terminals. The distribution of a major component of APP immunoreactive fibers exhibits a marked similarity to that of previously described norepinephrine‐containing hypothalamic afferents. Other groups of APP immunoreactive perikarya and fibers appear to represent components of intrinsic dienc

ISSN:0092-7317    

DOI:10.1002/cne.902170202

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

年代:1983

数据来源: WILEY

摘要:

AbstractAnatomical material from two series of monkeys(Macaca mulatta)was used to determine the full extent and visuotopic organization of striate projections to the pulvinar. One series was processed for degeneration by the Fink‐Heimer procedure following unilateral lesions of lateral, posterior, or medial striate cortex (representing the central, peripheral, and far peripheral visual field, respectively); collectively, the lesions included all of area 17. The second series was processed for autoradiography following tritiated amino‐acid injections into striate sites representing the center of gaze and eccentricities ranging from 0.5° to greater than 30° from fixation in both the upper and lower fields.The results indicate the existence of two separate striate projection zones within the pulvinar. One, the PI/PL zone, is located primarily within the inferiorpulvinar (PI) but extends into the adjacentlateral pulvinar (PL). The other, the PL zone, is located entirely within the lateral pulvinar and partially surrounds the first zone along its dorsal, lateral, and ventral aspects.Within the PI/PL zone, striate projections are topographically organized and represent the entire contralateral visual field. Central vision is represented laterally and posteriorly, with the fovea represented at the caudal pole of the nucleus; conversely, far peripheral vision is found medially and anteriorly, adjacent to the medial geniculate nucleus. The representation of the horizontal meridian runs obliquely across PI/PL, such that the upper visual field is located ventrolaterally and the lower visual field dorsomedially. The representation of the vertical meridian is located along the lateral margin of PI in anterior sections of the pulvinar, but within PL in posterior sections. Thus, the vertical meridian appears to form the border between the lateral margin of the PI/PL zone and the medial margin of the PL zone. At the lateral margin of the PL zone is the representation of its horizontal meridian. Striate projections to the PL zone, unlike those to the PI/PL zone, are limited to the representation of central vision. These results suggest that striate inputs contribute to the visual properties of neurons (Bender, 1981 a) throughout the PI/PL zone, but are insufficient to explain the visual properties of neurons outside of the central visual field representation in the PL

ISSN:0092-7317    

DOI:10.1002/cne.902170203

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

年代:1983

数据来源: WILEY

摘要:

AbstractThe nucleus basalis of Meynert in the squirrel monkey exhibits numerous labeled neurons following the retrograde transport of horseradish perox‐idase from occipital cortical injection sites. The typically large, often clustered, labeled cells are seen most frequently in association with the fibrous bordering structures of the substantia innominata and in the internal and external laminae of the globus pallidus. Ultrastructurally the copious cytoplasm of nucleus basalis neurons abounds with organelles. Large, vacuo‐lated lipofuscin granules proliferate as a function of age and are not evident in younger monkeys. Approximately 4% of the somal surface is occupied by symmetrical synapses with either flat or pleomorphic vesicles. The remainder is covered mostly by neuroglial processes. Somatic spines bearing synapses are occasionally observed. In the neuropil surrounding nucleus ba‐salis somata, the synapses onto dendrites and spines are mostly asymmetrical with large, round vesicles. Labeled nucleus basalis cells in the substantia innominata immediately lateral to the optic tract are larger and rounder than cells in the internal and external pallidal laminae. However, no remarkable ultrastructural differences were observed between nucleus basalis so‐mata in the substantia innominata and external pallidal lamina, or between horseradish peroxidase‐labeled and unlabeled la

ISSN:0092-7317    

DOI:10.1002/cne.902170204

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

年代:1983

数据来源: WILEY

摘要:

AbstractThe ultrastructure of synaptic terminals of rat rod photoreceptors was studied in light‐adapted and dark‐adapted states. In the light‐adapted state, horizontal cell processes embedded in the photoreceptor terminal show smooth surface contours and are ovoid in cross section. In the dark‐adapted state, fingerlike protrusions of photoreceptor cytoplasm extend into the horizontal cell processes on either side of the synaptic ribbon. An electron‐dense structure lies under the horizontal cell membrane that surrounds these fingerlike protrusions. This submembrane specialization is generally associated with areas of concavity of the horizontal cell membrane; it occurs in goldfish rods as well as rat rods. The protrusions and the horizontal cell specialization may be involved in membrane dynamics during synaptic

ISSN:0092-7317    

DOI:10.1002/cne.902170205

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

年代:1983

数据来源: WILEY

摘要:

AbstractThe distribution of cholecystokinin in the spinal cord was investigated by immunohistochemistry. Throughout the length of the spinal cord cholecystokinin immunoreactivity was found in laminae I and II, in the spinal re‐ticular nucleus, and in the surroundings of the central canal. On the basis of the cholecystokinin pattern lamina II could be divided into a dorsal and ventral part.In the lumbar and sacral spinal cord additional terminal fields of cholecystokinin immunoreactive boutons unique to these levels were found. They corresponded to the intermediolateral nucleus and to the medial lumbar sympathetic nucleus dorsal to the central canal in the first and second lumbar segment. Also the intermediolateral nucleus in L6–S1received a dense cholecystokinin positive input. Moreover, the area surrounding the central canal in L6–S1, contained many cholecystokinin immunoreactive structures. Combined retrograde tracing and immunocytochemistry revealed that the two cholecystokinin terminal fields characteristic for L1–L2and that sur‐rounding the intermediolateral nucleus in L6–S1were situated corresponding to preganglionic neurons innervating pelvic organs through the hypo‐gastric nerve or the pelvic nerves.It thus appears that the unique lumbosacral cholecystokinin is related to nuclei influencing pelvic structures, pointing to a special need for regulation of the organs involved in evacuation and sexual functions. Moreover, it is demonstrated that the caudal part of the spinal sympathetic system differs from the more cranial part with respect to type of afferent connections.The origin of the spinal cholecystokinin was investigated and it was found that neither complete transection of the spinal cord nor ipsilateral sectioning of three or four dorsal roots induced visible changes in the cholecystokinin staining pattern. Treatment of the caudal spinal cord with colchicine revealed the presence of cholecystokinin immunoreactive neurons in the intermediate gray, at the lateral border of the dorsal horn, in the dorsal horn proper, and in the substantia gelatinosa. These findings indicate that the majority of spinal cholecystokinin has a

ISSN:0092-7317    

DOI:10.1002/cne.902170206

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

年代:1983

数据来源: WILEY

摘要:

AbstractThe fiber connections of the nucleus tegmenti pedunculopontinus, pars compacta (TPc) were studied by means of the anterograde autoradiographic and retrograde horseradish peroxidase tracer methods. The limits of TPc, which is not a cytoarchitecturally distinct cell group in the cat, were estimated on the basis of autoradiographic experiments in which we plotted the distribution of afferent connections from the entopeduncular nucleus, motor cortex, substantia nigra, and subthalamic nucleus. We concluded that in the cat, TPc can most readily be identified by the terminal distribution of fibers originating in the substantia nigra. Deposits of radiolabel in the motor‐pre‐motor cortex, the entopeduncular nucleus, and subthalamic nucleus weakly labeled the same tegmental region. Parallel horseradish peroxidase experiments suggested that neurons near the entopeduncular nucleus, especially in the lateral hypothalamus and subthalamus, contribute to the pallido‐TPc pathway; that entopeduncular neurons projecting to TPc are most numerous in the ventral part of the nucleus; and that of the neocortical motor fields, both areas 4 and 6 project to TPc.An autoradiographic study of the efferent connections of TPc showed that the major connections were directed toward more rostral structures. Small deposits of labeled amino acids centered in TPc invariably elicited bilateral labeling of the pars compacta of the substantia nigra and the subthalamic nucleus, the densest label being on the ipsilateral side. Other structures variably or more sparsely labeled were: the posterior and lateral hypothalamus; centre median complex; an intermediate part of the lateral thalamic nucleus; central gray substance; nucleus parabrachialis pigmentosus (retro‐rubral nucleus); the raphe nuclei linearis intermedius, dorsalis, and magnus; nucleus reticularis tegmenti pontis; the pontine and medullary reticular for‐mation including the nuclei pontis oralis and caudalis; and the nucleus reticularis gigantocellularis, especially its ventral supraolivary part. These observations demonstrate that TPc shares some connections with a wider tegmental region, but that, in addition, TPc is characterized by a set of afferent and efferent connections that differentiate it from the surrounding teg‐mentum and affiliate it with the basal ganglia. By comparison with findings in the monkey and rat, these experiments further suggest that the connections of TPc may vary across mammalian species. The location and fiber connections of TPc indicate that it is probably distinct from the physiologically defined mesencephalic locomotor region, but suggest the hypothesis that TPc, as a part of an extrapyramidal tegmental loop‐circuit, may be involved in the production of simple re

ISSN:0092-7317    

DOI:10.1002/cne.902170207

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

年代:1983

数据来源: WILEY

摘要:

AbstractThe second‐order auditory neurons in the avian nucleus magnocellularis (NM) do not begin to grow permanent dendrites until about embryonic day 17 (E17), a few days before hatching. Since the auditory periphery and brain‐stem auditory nuclei are functional by E14 at the latest, the late appearance and growth of permanent dendrites in NM provides an unusual opportunity to examine the role of sensory experience in the very early stages of dendritic growth. We studied the development of NM dendrites in normal chickens and in animals with sustained monaural acoustic deprivation. In Golgi‐Hortega preparations at E17 and posthatching days 4 (P4), 10 (P10), and 60 (P60), the proportion of stained NM neurons with a dendritic process (“dendritic neurons”) and the length of these dendrites were measured. In normal animals the mean proportion of dendritic neurons rose from about 14% at E17 to 40% at P4 and thereafter. The mean length of NM dendrites in normal animals, however, grew significantly until P10, rising from about 14 μm at E17 to 48 μm by P4, and about 100 μm at P10 and P60. A 40‐dB monaural conductive hearing loss maintained with plastic earplugs from E18 on produced substantial retardation of dendritic growth after P4; at P10 the difference in length between deprived and nondeprived dendrites was 32% and at P60 was 38%. The proportion of dendritic neurons in the deprived NM and the mean diameter of the deprived dendrites were not affected by deprivation. Deprived dendrites in experimental animals were also significantly shorter than those in normal control animals. The length of nondeprived dendrites in experimental animals did not differ from that of controls, arguing against any compensatory hypertrophy. The functions of NM dendrites in the central processing of auditory information are as yet unknown. The facts that these dendrites (1) undergo their most rapid growth during the period of the animal's first exposure to airborne sound and (2) are markedly stunted by a nondeafferenting moderately severe acoustic deprivation suggest that acoustic experience has a strong facilitative function in the posthatching development of the cochlear nucleus. These results also suggest that afferent synaptic stimulation can affect the subsequent elongation, but not the initial outgrowth

ISSN:0092-7317    

DOI:10.1002/cne.902170208

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

年代:1983

数据来源: WILEY

摘要:

AbstractStudies on the morphological organization of the main olfactory bulb have indicated that there are subpopulations of granule cells with different dendritic patterns in the external plexiform layer (EPL). Small, extracellular injections of horseradish peroxidase (HRP) were made iontophoretically into superficial and deep parts of the EPL and the granule cell layer (GCL) in adult rats. Superficial EPL injections principally labeled superficial granule cell somata, whereas deep EPL injections labeled both superficial and deep granule cell somata. Injections in the superficial GCL labeled granule cell dendritic processes extending across the entire EPL. However, deep GCL injections labeled few granule cell dendrites in the superficial EPL, but labeled many such processes in the deep EPL. These results were the same in material processed with the Hanker‐Yates procedure, where the morphology of individual neurons could be studied, and in the more sensitive tetramethyl benzidineprocedure.Serial reconstructions of individual granule cells were made from both HRP and Golgi‐Kopsch material. The distal dendrites of deep granule cells reached only as far as the deep EPL, where they branched extensively and had many dendritic spines. The dendrites of superficial granule cells, however, reached the most superficial part of the EPL where they ramified most extensively. The superficial granule cells typically had a higher spine density in the superficial part of the EPL than in the deep part. On the basis of these results, we conclude that the superficial granule cells predominantly innervate the superficial EPL and that the deep granule cells exclusively innervate the deep EPL. Granule cells are believed to exert inhibitory influences on the bulbar output neurons, the mitral and tufted cells, through reciprocal dendrodendritic synapses. Since the secondary dendrites of the tufted cells ramify in the superficial EPL and the dendrites of most mitral cells ramify in deep EPL, the superficial and deep granule cells may preferentially modulate the responses of tufted and mitral cells, respectiv

ISSN:0092-7317    

DOI:10.1002/cne.902170209

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

年代:1983

数据来源: WILEY

ISSN:0092-7317    

DOI:10.1002/cne.902170201

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

年代:1983

数据来源: WILEY