摘要:

AbstractLight microscopic autoradiography was used to identify cells in the neostriatum that became labelled after the local injection of [3H]γ‐amino‐butyrate (GABA). The GABA‐accumulating cells comprised up to 15% of the total population of neurons. Thirty‐seven of these cells were examined in the electron microscope and it was found that they all had similar cytological characteristics, i.e., prominent nuclear indentations, a moderate volume of cytoplasm, rich in organelles, and sparse synaptic input to the perikaryon. Nine of the cells that had accumulated GABA were also impregnated following Golgi staining. These Golgi‐impregnated neurons were of medium size and all had dendrites that were aspiny, often varicose, and that occasionally followed a recurving path. After gold toning, the Golgi‐impregnated, GABA‐accumulating neurons were examined in the electron microscope and were found to receive boutons forming symmetrical or asymmetrical synaptic contacts on their somata and dendrites; the symmetrical synapses were most common on the cell body and proximal dendrites, while the distal dendrites mainly received boutons forming asymmetrical contacts.We conclude that one type of GABAergic neuron in the neostriatum is a type of medium‐sized aspiny neuron and that this neuron is likely to receive synaptic input both from neurons within the striatum and from neurons in distant brain regions. We suggest that this neuron is a local circuit neuron in the neostriatum since its morphological features are quite distinct from those of identified pr

ISSN:0092-7317    

DOI:10.1002/cne.902130202

出版商:Alan R. Liss, Inc.    

年代:1983

数据来源: WILEY

摘要:

AbstractAnterograde and retrograde tracing techniques were used to reveal that axons arising from neurons within the interlaminar zones and the S layers of the lateral geniculate nucleus of the squirrel monkey terminate within the supragranular layers of area 17. Specifically, our data indicate that the axons of the neurons housed within the S layers end in a patchlike fashion in cortical layers IIIa and IIIb, while neurons in the interlaminar zones project primarily to layer I. Both pathways may convey W‐cell information from the retina and the superior colliculus to the striate corte

ISSN:0092-7317    

DOI:10.1002/cne.902130203

出版商:Alan R. Liss, Inc.    

年代:1983

数据来源: WILEY

摘要:

AbstractFetal macaque chemosensory corpuscles during the last part of gestation contained chemosensory, sustentacular, and undifferentiated basal cells. Sustentacular cells had apical secretory granules and no specialized contacts with axons. Chemosensory cells contained basal collections of 80–100 nm dense core granules, and specialized axonal contacts of three types—afferent synapses, efferent synapses, and subsurface cisternae. Afferent synapses were commonly present on electron opaque cells with many 80–100‐nm granules, typical 40–60‐nm synaptic vesicles, and a few cisternae of smooth or granular endoplasmic reticulum. Cells with subsurface cisternae and/or efferent synapses were usually electron lucent, lacked vesicles and granules, and contained numerous intracytoplasmic cisternal elements. A continuum of intermediate forms was observed. It is postulated that transition of synaptic arrays accompanies the maturation of individual chemose

ISSN:0092-7317    

DOI:10.1002/cne.902130204

出版商:Alan R. Liss, Inc.    

年代:1983

数据来源: WILEY

摘要:

AbstractThe piriform cortex was studied in the adult opossum with rapid Golgi and Golgi‐Cox techniques.Most pyramidal cells in the deep part of layer II and layer III resemble those in other parts of the cerebral cortex by virtue of a single apical dendritic trunk, multiple basal dendrites, a large number of small to medium dendritic spines, and a deeply directed axon. Pyramidal cells in the superficial part of layer II are similar with the exception that “secondary” apical dendrites often emerge directly from the cell body rather than from a single primary trunk.With conservative criteria for categorization, nine different types of nonpyramidal cells were distinguished, four of which have not been previously described. Layer I contains a small number of neurons with both smooth and spiny dendrites including distinctive fusiform cells with large somatic appendages. As in other species, the most common type of nonpyramidal neuron in layer II is the semilunar cell which has only apically directed dendrites. These cells have distinctive large spines confined to their distal dendritic segments. The mid to deep portion of layer III contains multipolar neurons with smooth dendrites that resemble the well‐known large stellate cells in neocortex. In addition, layer III contains three non‐pyramidal neuron types with spiny dendrites: (1) fusiform and multipolar cells with complex, branched dendritic appendages and somatic spines, (2) very large multipolar cells (up to 35 μm mean diameter) with large‐diameter dendrites that give rise to abruptly tapering side branches and filiform spines, and (3) multipolar cells with profusely spiny dendrites. In all three layers, small neurons have been found with spherical cell bodies and “axoniform” dendrites that resemble the so called neurogliaform neurons described in a variety of brain areas. A striking feature of the organization of the piriform cortex is that, with the exception of the neurogliaform neurons, the different types of nonpyramidal cells tend to be segregated in individual layers or sublayers.Physiological implications of the results are discussed. Remarks are also made concerning the potential of the piriform cortex as a model

ISSN:0092-7317    

DOI:10.1002/cne.902130205

出版商:Alan R. Liss, Inc.    

年代:1983

数据来源: WILEY

摘要:

AbstractThe cellular organization of the Wulst was studied in Nissl‐ and Golgi‐stained brain sections in order to identify the visual receptive neurons. Golgi‐impregnated neurons were divided into four types according to their soma size, dendritic configuration, and density of spine distribution. Type I neurons, the largest cells in the Wulst, have long, straight dendrites with many spines. Type II neurons are medium‐sized cells with long, straight dendrites. These dendrites have numerous spines. Type III neurons are medium‐sized or small cells with spine‐free dendrites. Type IV neurons, the smallest cells in the Wulst, have short dendrites with sparse spines. The projections of the nucleus dorsolateralis anterior thalami pars lateralis (DLL) to the Wulst were determined by the Fink‐Heimer method. After lesions of the DLL, degenerating terminals are seen in a dorsolateral portion of the nucleus intercalatus hyperstriatum accessorium where the types II, III, and IV neurons are distributed. Postsynaptic elements to the DLL axons were identified by reconstruction of electron microscopic serial sections. Most of the postsynaptic elements were dendritic spines of the type II and IV neurons and a few were dendritic shafts of the typ

ISSN:0092-7317    

DOI:10.1002/cne.902130206

出版商:Alan R. Liss, Inc.    

年代:1983

数据来源: WILEY

摘要:

AbstractThe ventricular sulcal pattern and the cytoarchitecture of the brainstem ofXenopus laevis, a pipid frog which retains a lateral line system throughout life, were studied in transverse Nissl‐ and Klüver‐Barrera‐stained serial sections. Four distinct longitudinal sulci, the sulcus medianus inferior, the sulcus intermedius ventralis, the sulcus limitans, and the sulcus medianus superior, could be distinguished. With the aid of the usual cytoarchitectonic criteria 42 cell groups were delineated; seven of these are primary efferent or motor nuclei, 13 are primary efferent or sensory centers, seven nuclei are considered to be components of the reticular formation, and the remaining 15 cell masses can be indicated as “relay” nuclei. In order to provide a basis for experimental work, the topographical position of the nuclei is illustrated in photomicrographs of representative levels and in graphical reconstructions.The distribution of the cell masses and their relations to the ventricular sulci were studied with the aid of the reconstruction procedure termed topological analysis (cf. Nieuwenhuys, '74; Fig. 19). This analysis yielded the following results. The sulcus limitans extends throughout almost the entire brainstem, dividing this part of the brain into a motor basal plate and a sensory alar plate. The cell masses in the rhombencephalic basal plate fit into two longitudinal zones, a medial area ventralis and a lateral area intermedioventralis. The former contains somatomotor centers of primary and higher order, whereas the latter is composed of three primary visceromotor nuclei and one visceromotor coordinating center. The rhombencephalic alar plate is occupied by viscerosensory, general somatosensory, and special somatosensory cell masses. Two centers, the nucleus fasciculi solitarii and the nucleus visceralis secundarius, represent together a discontinuous viscerosensory zone, which is situated immediately dorsal to the sulcus limitans. The general somatosensory nuclei, i.e., the gracile and cuneate nuclei, the nucleus tractus descendens of V, and the nucleus princeps of V constitute a zone which largely overlaps the viscerosensory zone. The special somatosensory area, i.e., the area of termination of (1) primary vestibular, (2) primary acoustic, and (3) lateral line nerve fibers, is strongly developed and occupies a considerable part of the alar plate. Presumably, the fibers of each of the three categories mentioned terminate in three separate zones of gray. The midbrain can also be subdivided bilaterally into a basal plate and an alar plate. The former occupies the medial part of the tegmentum mesencephali and may be considered as the rostral extreme of the somatomotor zone. The latter comprises the lateral tegmentum and the tectum, areas which are chiefly occupied by special somatosensory (visual, acoustic, lateral lin

ISSN:0092-7317    

DOI:10.1002/cne.902130207

出版商:Alan R. Liss, Inc.    

年代:1983

数据来源: WILEY

摘要:

AbstractThe ventricular sulcal pattern and the cellular structure of the brainstem of the reedfishErpetoichthys calabaricuswere studied in transversely cut Nissl‐, Klüver‐Barrera‐, and Bodian‐stained serial sections. Six longitudinal sulci, the sulcus medianus inferior, the sulcus intermedius ventralis, the sulcus limitans, the sulcus intermedius dorsalis, the sulcus medianus superior, and the sulcus lateralis mesencephali could be distinguished. A seventh groove, the sulcus isthmi, clearly deviates from the overall longitudinal pattern of the other sulci. Although inErpetoichthysmost neuronal perikarya are contained within a diffuse periventricular gray, 32 cell masses could be delineated; six of these are primary efferent or motor nuclei, seven are primary afferent or sensory centers, nine are considered to be components of the reticular formation, and the remaining ten may be interpreted as “relay” nuclei.In order to study the zonal pattern of the brainstem, this structure was subjected to a topological analysis (cf. Nieuwenhuys, '74 and Fig. 15) which yielded the following result. In the rhombencephalon the gray matter is arranged in four longitudinal columns or areas termed area ventralis, area intermedioventralis, area intermediodorsalis, and area dorsalis. In many places the sulcus intermedius ventralis, the sulcus limitans, and the sulcus intermedius dorsalis mark the boundaries between these morphological entities. These longitudinal areas coincide largely, but not entirely, with the so‐called functional columns of Herrick and Johnston. The most obvious incongruity is that the area intermediodorsalis contains, in addition to the nucleus of the solitary tract, three nonviscerosensory cell masses, namely, the nucleus vestibularis magnocellularis and parvocellularis and the nucleus of the tractus descendens of V. The four longitudinal zones cannot be distinguished in the mesencephalon nor can the sulcus limitans be recognized here. Functionally, however, the medial part of the tegmentum mesencephali may be considered the rostral extreme of the somatomotor column, whereas the remainder of the midbrain contains a number of somatos

ISSN:0092-7317    

DOI:10.1002/cne.902130208

出版商:Alan R. Liss, Inc.    

年代:1983

数据来源: WILEY

摘要:

AbstractThe projections to lobulus simplex and Crus I of the cerebellum from various brainstem nuclei have been examined in adult rats by using the retrograde fluorescent double labeling technique. True blue was injected into the lobulus simplex on one side and nuclear yellow on the other and the brainstem was examined for labeled neurons. The lateral reticular nucleus, pontine tegmental reticular nucleus, and nucleus praepositus hypoglossi were similar to the equivalent nuclei in other species but all contained double‐ as well as single‐labeled neurons and it was concluded that these nuclei have neurons whose axons branch to both sides of the cerebellum. More neurons in the rostral part of the lateral reticular nucleus were bilaterally projecting than in the caudal and the significance of this in relation to its afferents is considered.The individual neurons in the pontine nuclei, inferior olivary nucleus, and cuneate nuclei only appear to project to one side and the recent evidence for axonal branching of pontine neurons in the cat is discus

ISSN:0092-7317    

DOI:10.1002/cne.902130209

出版商:Alan R. Liss, Inc.    

年代:1983

数据来源: WILEY

ISSN:0092-7317    

DOI:10.1002/cne.902130201

出版商:Alan R. Liss, Inc.    

年代:1983

数据来源: WILEY