摘要:

AbstractThe present study labels the neuronal cell bodies that give rise to afferent fibers that innervate the bladder of cat and rat. The method used was the retrograde transport of horseradish peroxidase (HRP) from its injection site in the bladder to cells in the various dorsal root ganglia. In the rat, the labelled cells are located in the L1–L2and L6–S1dorsal root ganglia. In the cat, the labelled cells are located in the L2–L5and S1–S4dorsal root ganglia. This confirms older clinical findings, and for the first time directly demonstrates the afferent cell bodies for the bladder. The bladder afferents are small ganglion cells in both rat and cat, and because there is a correlation between the size of axon and the cell body from which it originates, we conclude that the great majority of bladder afferents are small myelinated or unmyelinated axons. In addition, by restricting the HRP to one side of the bladder, we were able to show that some afferent cell bodies send their distal processes across the midline. These results will be useful in considerations of the neural control of bladder f

ISSN:0092-7317    

DOI:10.1002/cne.901920202

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

年代:1980

数据来源: WILEY

摘要:

AbstractThe morphology of ganglion cells in the cat's retina has been examined in Golgi‐impregnated whole mounts. The α‐, β, and γ‐cell groups described by Boycott and Wässle ('74) were observed. Also observed were may cells with wide dendritic fields typical of γ‐cells, and medium‐sized somas more usually associated with β‐cells. It is suggested that these cells belong to the γ‐cells group, adding to the variety already described by Boycott and

ISSN:0092-7317    

DOI:10.1002/cne.901920203

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

年代:1980

数据来源: WILEY

摘要:

AbstractEvidence is presented of gradients between nasal and temporal areas of the cat's retina in the properties of their ganglion cell populations. Mean ganglion cell size is greater in temporal retina than in nasal retina, partly because the α‐ and β‐cells of temporal retina are distinctly bigger than their counterparts in nasal retina, and partly because more medium‐sized cells, and fewer small cells, are to be found in temporal retina. This high proportion of medium‐sized ganglion cells may reflect a high proportion of β‐cells or of the medium sized γ‐cells described by Stone and Clarke ('80). Several of these differences can be related to prior morphological, electrophysiological, and behavioural observations in the cat, and similar differnces have been reported in several other mammalian species. Evidence is presented that, in the cat, at least some of these differences are less marked near the vertical meridian of the retina than more temporally or nasally. The present results may therefore, be evidence of a nasal‐temporal gradient in retinal structure and function common to many mammals, and distinct from previously recognised gradients in ganglion cell properties related to the area centralis and visual strea

ISSN:0092-7317    

DOI:10.1002/cne.901920204

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

年代:1980

数据来源: WILEY

摘要:

AbstractThe distributions of small and medium‐sized ganglion cells in the cat's retina have been studied.The soma size ranges of ganglion cells projecting to the superior colliculus and the A‐laminae of the dorsal lateral geniculate nucleus were determined by the retrograde transport of horseradish peroxidase. Confirming previous work, the results suggest a division of the overall soma population into large, medium and small ranges. The large somas are the cell bodies of α‐ or Y‐cells; the small somas are the cell bodies of γ‐ or W‐cells, most of which project to the superior colliculus; and the medium‐sized somas include the cell bodies of β‐ or X‐cells and of γ‐ or W‐cells, most of which project to the forebrain.The small‐soma (collicular‐projecting) cells have a strongly streaky distribution, i.e., the isodensity lines in a map of their distribution are markedly elongated horizontally. These cells form the principal component of the visual streak, especially in nasal retina. The medium‐soma (forebrain‐projecting) cells also show some streakiness, i.e., their isodensity lines are also elongated horizontally, but less markedly than for small cells. The results also show differences between nasal and temporal retina in the distributions of medium‐sized and small somas.It is suggested that the patterns of distribution of small and medium cells may be reflected in the topography of visual centres of the m

ISSN:0092-7317    

DOI:10.1002/cne.901920205

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

年代:1980

数据来源: WILEY

摘要:

AbstractThe adult and developmental morphology of spiny and aspiny neurons in the dog caudate nucleus was examined using the Golgi‐Kopsch technique. In the adult, three types each of spiny and aspiny neurons were identified based upon dendritic morphology and cell soma size. They corresponded in large part to those neurons described previously in the caudate nuclei of the rat, cat, and monkey. At birth, dendrites of spiny neurons possessed varicosities, filopodia, and thick proximal dendritic stumps—all characteristic of immaturity. Maturation of these processes involved the thinning of proximal dendrites, lengthening of dendritic shafts, and growth of dendritic spines. Although most of the dendritic maturation occurred during the first postnatal month, spine densities and dendritic lengths of spiny I neurons at 30 days were still less than those seen in the adult. Aspiny I neurons were also immature at birth but lacked the filopodia and thicker proximal dendrites that characterized immature spiny neurons. Aspiny dendritic development involved primarily the lengthening of dendritic processes; by 30 days the aspiny I neurons were indistinguishable from those seen in the adult. These results suggest that dendritic development of spiny I neurons may extend well past the end of the first postnatal month and that studies investigating functional development in the caudate nucleus should consider the relatively extended time period required for maturation of these primary synaptic si

ISSN:0092-7317    

DOI:10.1002/cne.901920206

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

年代:1980

数据来源: WILEY

摘要:

AbstractMicroelectrode mapping techniques were employed in the cat's auditory cortex to relate the best frequencies of a large population of neurons with their spatial loci. Based upon the best‐frequency distribution, the auditory region was divided into four complete and orderly tonotopic representations and a surrounding belt of cortex in which the tonotopic organization was more complex. The four auditory fields occupy a crescent‐shaped band of tissue which comprises portions of both the exposed gyral surfaces and sulcal banks of the ectosylvian cortex. The anterior auditory field (A) is situated most rostrally upon the anterior ectosylvian gyrus. It extends upon the ventral bank of the suprasylvian sulcus and upon the banks of the anterior ectosylvian sulcus. Adjoining field A caudally is the primary auditory field (AI), which extends across the middle ectosylvian gyrus and portions of both banks of the posterior ectosylvian sulcus. The representations of the highest best frequencies in fields A and AI are contiguous. Caudal and ventral to AI are located the posterior (P) and ventroposterior (VP) auditory fields. They lie mainly upon the caudal bank of the posterior ectosylvian sulcus but also extend upon the rostral bank and upon the posterior ectosylvian gyrus. The low best‐frequency representations of fields AI and P are contiguous, whereas the low best‐frequency representation of field VP lies near the ventral end of the posterior ectosylvian sulcus. Fields P and VP are joined along their middle and high best‐frequency representations. Within each auditory field isofrequency lines defined by the spatial loci of neurons with similar best frequencies are oriented orthogonal to the low‐to‐high best‐freq

ISSN:0092-7317    

DOI:10.1002/cne.901920207

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

年代:1980

数据来源: WILEY

摘要:

AbstractTopographic distributions of cortico‐cortical projections from the primary (AI), anterior (A), posterior (P), ventroposterior (VP), and second (AII) auditory fields were studied in relation to tonotopic maps in combined anatomical and electrophysiological experiments. Distributions of axon terminals were determined by autoradiographic labeling with tritiated proline and leucine. Each of fields A, AI, P, and VP is connected with the other three in the same hemisphere as well as with a number of other auditory cortical areas. Additionally, neurons in each of the fields studied were found to project to the lateral bank of the collateral fissure. In general, regions near the injection site receive more densely labeled projections than do more distant targets. Neurons in each field were found to project to one or more areas in the opposite hemisphere. Only similar portions of the best‐frequency representations in fields A, AI, P, and VP are interconnected. A single isotope injection generally produced multiple patches of labeling within each of several cortical fields. Within AI, projections from contralateral fields A and AI and from ipsilateral fields A and P terminate in patches which are often elongated in a direction parallel to the low‐to‐high best‐frequency gradient. A divergence in the projections from one field upon another is apparent in many experiments. Within fields A, AI, P, and VP, patches of label are distributed along a band of cortex oriented parallel to isofreque

ISSN:0092-7317    

DOI:10.1002/cne.901920208

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

年代:1980

数据来源: WILEY

摘要:

AbstractDegeneration of hippocampal CA3 pyramidal cells was investigated by light and electron microscopy after intraventricular injection of the potent convulsant, kainic acid. Electron microscopy revealed evidence of pyramidal cell degeneration within one hour. The earliest degenerative changes were confined to the cell body and proximal dendritic shafts. These included an increased incidence of lysosomal structures, deformation of the perikaryal and nuclear outlines, some increase in background electron density, and dilation of the cisternae of the endoplasmic reticulum accompanied by detachment of polyribosomes. Within the next few hours the pyramidal cells atrophied and became electron dense. Then these cells became electron lucent once more as ribosomes disappeared and their membranes and organelles broke up and disintegrated. Light microscopic changes correlated with these ultrastructural observations. The dendritic spines and the initial portion of the dendritic shaft became electron dense within four hours and degenerated rapidly, whereas the intermediate segment of the dendrites swelled moderately and became more electron lucent. No degenerative changes were evident in pyramidal cell axons and boutons until one day after kainic acid treatment.Less than one hour after kainic acid administration, astrocytes in the CA3 area swelled, initially in the vicinity of the cell body and mossy fiber layers. It is suggested that the paroxysmal discharges initiated in CA3 pyramidal cells by kainic acid served as the stimulus for this response. Phagocytosis commenced between one and three days after kainic acid administration, but remained incomplete at survival times of 6–8 weeks. Astrocytes, microglia, and probably oligodendroglia phagocytized the degenerating material.These results point to the pyramidal cell body and possibly also the dendritic spines as primary targets of kainic acid neurotoxicity. In conjunction with other data, they support the view that lesions made by intraventricular kainic acid can serve models of epileptic brain damag

ISSN:0092-7317    

DOI:10.1002/cne.901920209

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

年代:1980

数据来源: WILEY

摘要:

AbstractCatecholamine‐containing neuronal processes penetrate to the outer superficial layers of the developing neocortex via the lateral neocortex anlage by embryonic day (ED) 16, only 48 hours after the final cell division of the catecholamine neurons in the mesencephalon and pons‐medulla. Sagittal sections were taken from a series of perfused embryos at precise time‐intervals after insemination. The corpus striatum receives a large catecholamine input and serves as a reference for tracing the very fine varicose processes that course through the caudate nucleus to innervate the more rostral structures of the developing neocortex cerebri. The input fibers to the neocortex arrive via three to four small fiber bundles, entering chiefly at the ventro‐rostral aspect. The bundles then bifurcate into the deep and superficial layers of the cortex. Between ED16 to ED21 the innervation progresses in ventral to dorsal and rostral to caudal directions. Embryonically, fluorescent fibers are observed in the outermost superficial layer and in the intermediate zone, below the cortical plate; only rarely are they seen crossing the cortical plate. The demonstration of monoaminergic neuronal fibers reaching neocortical structures by ED16 adds further weight to the speculation that they may play a role in induction and differentiation, and suggests that post‐natal experimental manipulations using ascending‐bundle lesions will have been performed at least five days after the arrival of catecholamine fibers at their cortical d

ISSN:0092-7317    

DOI:10.1002/cne.901920210

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

年代:1980

数据来源: WILEY

摘要:

AbstractElectrolytic lesions were placed in the dentate and interpositus nuclei of the monkeyM. mulattaand the resulting anterograde degeneration was stained with the Wiitanen or Nauta‐Laidlaw techniques. Two of 19 lesions produced preterminal degeneration in the oculomotor nuclei. In both cases the lesions also damaged vestibular area “y” subjacent to the rostral pole of the dentate nucleus. The course and terminal distribution of anterograde degeneration to the oculomotor nuclei was the same in both cases. Degenerating fibers were found in lateral parts of the ipsilateral MLF, and preterminal degeneration was found in the ipsilateral abducens and trochlear nuclei and the dorsal subdivision of the oculomotor nucleus. Degenerating fibers were also traced from the crossed brachium conjunctivum to the contralateral paramedian subdivision of the oculomotor nucleus. These fibers appeared to course in dorsomedial parts of the brachium. Lesions of the dentate and interpositus nuclei which did not damage area “y” produced no anterograde axonal degeneration in the MLF or the oculomotor nerve nuclei. The results are discussed with regard to previous reports of cerebello‐oculomotor fibers originating in the dentate and interpositus nuclei. The results suggest that area “y”, rather than the cerebellar nuclei, projects principally to oculomotor neurons that control vertica

ISSN:0092-7317    

DOI:10.1002/cne.901920211

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

年代:1980

数据来源: WILEY