摘要:

AbstractAfferent connections to the rat locus coeruleus (LC), which contains exclusively noradrenergic neurons, have been traced using the technique of retrograde transport of horseradish peroxidase (HRP). In order to ensure accurate placement of adequate amounts of HRP in the LC, a microiontophoretic delivery technique coupled with single cell recording was employed. The use of electrophysiological “landmarks” as aids in placing the injections is described. Following HRP injections into the LC, forebrain structures containing labelled neurons included the insular cortex, the central nucleus of the amygdala, the medial, lateral and magnocellular preoptic areas, the bed nucleus of the stria terminalis, and the dorsomedial, paraventricular and lateral hypothalamic areas. In the brainstem reactive neurons were observed in the central grey substance, the reticular formation, the raphe, vestibular, solitary tract and lateral reticular nuclei. In particular, the areas of catecholamine cell groups A1, A2and A5appeared to contain many reactive cells. Labelled neurons were also observed in the fastigial nuclei and in the marginal zones of the dorsal horns of the spinal cord. This pattern of afferent innervation supports suggestions for a role for the LC in behavioral arousal mechanisms and autonomic regulat

ISSN:0092-7317    

DOI:10.1002/cne.901780102

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

年代:1978

数据来源: WILEY

摘要:

AbstractThe results of the present anatomical study on macaque monkeys concern some aspects of the dorsal column nuclei, their projection to the thalamus and the cytoarchitecture and topography of the recipient areas in the thalamus for the somatosensory pathways. Some observations regarding the cytoarchitecture of the dorsal column nuclei are reported; the gracile nucleus differs cytoarchitectonically over the rostrocaudal dimension in a way similar to the feline nucleus; the cuneate nucleus has a distinct pars rotunda (Ferraro and Barrera, '35) which might be analogous to a similar structure in the raccoon shown to be activated by afferents from the volar side of the hand and digits (Johnson et al., '68). Cytoarchitectonic observations and other arguments suggesting the presence of the nucleus Z in the monkey are presented.In Nissl stained frontal sections, cut in the stereotaxic frontal plane as well as in sections cut perpendicular to the long axis of the brain stem the cytoarchitecture and topography of the posteromedial, ventroposterior and centrolateral thalamic nuclei of the macaque were analysed. The posteromedial nucleus (POm) has been found to include portions of Olszewski's ('52) magnocellular medial geniculate, suprageniculate and pulvinar nuclei. The nucleus ventralis posterolateralis (VPL) corresponds to the main portion of Olszewski's VPLc, whereas most of his VPLo corresponds to the nucleus ventralis intermedius of Hassler ('59) and Mehler ('71).Electrolytic lesions were used to study the projection from the gracile and cuneate nuclei to the thalamus. With postoperative survival periods of 6 to 14 days the resulting degeneration was studied in frontal sections stained according to the Wiitanen modification of the Fink‐Heimer method. Both the gracile and cuneate nuclei project profusely to the contralateral nucleus ventralis posterolateralis and more sparsely to the contralateral posteromedial nucleus and the zona incerta. A distinct somatotopic organization exists in the projection to the ventroposterior nucleus, but not in that to the other target areas. The projection to the ventroposterior nucleus is very dense and evenly distributed except rostrally and dorsally, where it is more scattered.It is concluded that the posteromedial and the ventroposterior thalamic nuclei are very similar in monkeys and cats regarding cytoarchitecture, topography and afferent projections from the dorsal column nucle

ISSN:0092-7317    

DOI:10.1002/cne.901780103

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

年代:1978

数据来源: WILEY

摘要:

AbstractA quantitative and qualitative study of the septotemporal organization of the hippocampal mossy fiber system has been carried out in the rat. Transverse sections of isolated and extended hippocampi were stained according to Nisel's or Timm's method. At 12 equidistant levels covering the entire length of the hippocampus the following parameters were measured: the length of the granule cell layer and the mossy fiber layer, the area of the fields containing mossy fiber boutons, the number of granule cells, and the number of pyramidal cells in the hilus and in the regio inferior.Septally the pyramidal layer of the regio inferior is broad and the cells within the layer are relatively widely spaced. Here the mossy fiber boutons intrude deep into the layer. At more temporal levels the cells are tightly packed, the cell‐layer is narrower, and the boutons predominantly terminate suprapyramidally.The length of the granular layer is greatest septally, while the length of the mossy fiber layer is greatest temporally. The area of the hilus, occupied by the mossy fiber boutons, is large at most of the temporal levels and small at the septal levels, whereas in CA3 the reverse is true. The greatest number of granule cells was found at the more septal levels. Conversely, the majority of the pyramidal cells in the hilus and in the regio inferior is situated temporally. The ratio of granule cells to pyramidal cells (hilus and regio inferior together) declines linearly from approximately ten at septal levels to approximately one at temporal levels. Because the mossy fibers are distributed fairly transverse to the long axis of the hippocampus, the variation in the ratio of granule cells to pyramidal cells reflects a corresponding variation in the number of innervating to innervated cells within the mossy fiber syste

ISSN:0092-7317    

DOI:10.1002/cne.901780104

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

年代:1978

数据来源: WILEY

摘要:

AbstractThe mossy fibers, a major intrinsic hippocampal pathway connecting the dentate granule cells with the pyramidal cells in CA4 and CA3, have been reexamined in rats using mainly Fink‐Heimer silver impregnation methods for demonstration of degenerating axons. By extending isolated hippocampi and cutting sections normal to the long axis, simple two‐dimensional reconstructions of both the lesions and the resultant degeneration could be made.In the hilus, the zone with the greatest concentration of degenerating boutons was found between the lesioned granule cells and the CA3 pyramidal cells abutting on the hilus; outside this zone the concentration declines rather rapidly. Degenerating boutons were also observed in low concentration up to 200‐300 μm septal and temporal to the lesion.The mossy fibers in CA3 nearest the hilus have an intrapyramidal course and display a lamellar organization with fibers from the granule cells of the medial blade lying deep to those from the dentate crest. These in turn lie deep to those from the granule cells of the lateral blade.A mediolateral difference in the projection of the granule cells on the CA3 pyramidal cells was discovered: fibers from the medial granule cells descend about 600 μm in the temporal direction, whereas fibers from the lateral granule cells descend about 1,200 μm. This causes a divergence of the fibers from one single level, especially of the part of the fibers, being farthest away from the hilus. The degree of descent of the fibers from each mediolateral position of the granule cells was constant at all septotemporal levels

ISSN:0092-7317    

DOI:10.1002/cne.901780105

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

年代:1978

数据来源: WILEY

摘要:

AbstractRecent evidence suggests that the hypothalamic ventromedial nucleus contains a wide variety of functionally specialized neurons, some of which are located within discrete regions of the nucleus. However, regional morphologic variations in neuronal populations within the HVM have not been demonstrated. In the present report, the neurons of the HVM were studied in young adult, male rats with the electron microscope. The collection and analysis of cytologic data were systematized with reference to location on a histologic map of the HVM, which was prepared prior to fine structural study.Neurons of the HVM were observed to exhibit regional variations in cytology. For example, cisternae of the rough endoplasmic reticulum in the anterior and dorsomedial regions of the nucleus are commonly collected into regular stacks typical of Nissl bodies. In contrast, rough cisternae in the posterior ventrolateral region of the HVM are often extremely long and pleomorphic, and form broad, loosely organized Nissl zones, in which occur myelin figures and wide varieties of cytoplasmic filamentous bodies.Other neurons located principally in the ventrolateral and posterior regions of the nucleus are characterized by the presence of whorled bodies. Still others restricted to the lateral rim of the nucleus are conspicuous by virtue of their enormous size and massive accumulation of Nissl material.One extremely unusual variety of HVM neuron is distinguished by the presence of large, acristic mitochondria, polysomal disaggregation, and aberrant nucleolar morphology. These cytologic features may indicate metabolic quiescence and perhaps anaerobiosis.Possibly these region‐centered variations in neuronal cytology reflect the functional parcellation of the HV

ISSN:0092-7317    

DOI:10.1002/cne.901780106

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

年代:1978

数据来源: WILEY

摘要:

AbstractQuantitative studies of synaptic ultrastructure were made in the upper layers of cat cerebral cortex. Tissues were from intact cortex and from long‐term (chronic) undercut cortex with or without electrical stimulation. The synaptic effects of chronic electrical stimulation of denervated cortex are most readily understood as growth and remodeling of synaptic elements. Associated with chronic stimulation were increases in: symmetric membrane contacts; areas of round and flat vesicle containing terminals; dendritic shaft contacts; and synaptic contact lengths. Even without stimulation there were indications of synaptic plasticity in denervated cortex; compared with intact cortex, synapses having symmetric membrane contacts showed an increase in bouton area and an increase in synaptic contacts on dendritic shafts. These data are consistent with the observations of others in which axonal terminal growth occurred after deafferentation. But it appears that chronic electrical stimulation in the adult nervous system promotes significantly more plasticity than occurs without stimulation. In a functional sense stimulation in the present experiments produced effective inhibition which did not occur with denervation alone. Thus the plasticity observed with stimulation had both structural and functional component

ISSN:0092-7317    

DOI:10.1002/cne.901780107

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

年代:1978

数据来源: WILEY

摘要:

AbstractA detailed account of the distribution of immunoreactive substance P‐containing structures in the rat central nervous system is presented, from results obtained by applying an indirect immunofluorescent technique. High densities of substance P‐containing nerve terminals were present in sensory nuclei and other non‐sensory structures such as thalamus, hypothalamus and extrapyramidal system. Substance P‐reactive neuron cell bodies were present in spinal root ganglia, nucleus habenulae medialis, nucleus interpeduncularis, caudoputamen and globus pallidus. Most of the neocortex and the cerebellar cortices had no substance P‐positive elements. The results support the hypothesis that substance P may be a widespread neurotransmitter in the central nervo

ISSN:0092-7317    

DOI:10.1002/cne.901780108

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

年代:1978

数据来源: WILEY

摘要:

AbstractMotor nuclei and primary afferent projections of branchial cranial nerves were shown with the CoCl2staining technique. Motor nuclei constitute a discontinuous column at the ventrolateral margin of the gray matter. The size of motoneurons decreases in the orocaudal direction within the column. The dendrites assemble in two main directions forming a dorsomedial and a ventrolateral dendritic array. The axons originate in the ventrolateral dendrites and run straight to the motor roots. Preganglionic vegetative neurons were found in a separate group at the level of the abducens nucleus, and intermingled with motoneurons at the level of the glossopharyngeus and vagus nuclei. Their axons join the visceral sensory roots of the respective nerve.The tractus spinalia trigemini has a short and weak ascending limb, and a strong descending limb which decussates in the first and second segments of the spinal cord. A few uncrossed large fibers continue as far as the midthoracic level, In addition to trigeminal fibers, a small contingent of facial fibers and a significant number of vagus fibers contribute to the tractus spinalis. Small caliber fibers of the tractus and fine collaterals of large caliber fibers terminate in a continuous column which lies, in its largest part, in the neuropil medial to the tractus. The pattern of fiber terminations in this area is identical with that in the substantia gelatinosa. This area is called the nucleus spinalis trigemini. Coarse collaterals terminate in a discontinuous column of large and medium‐sized neurons, extending caudally to the obex region. This area is the largest at the level of the trigeminus nucleus and is called the nucleus principalis trigemini.The cells of origin of the mesencephalic tractus of the trigeminus lie in the second and fourth layers of the optic tectum. The descending fibers run ventral to the tractus spinalis in a separate bundle. They emit collaterals to the large fiber termination areas and to branchiomotor nuclei. Direct contacts are established with trigeminus motoneurons. In the obex region a significant number of collaterals invade the dorsomedial part of the gray matter.The fasciculus solitarius begins at the level of the trigeminal nucleus and terminates in the commissura infima at the medullospinal border. The nucleus solitarius begins at the oral pole of the glossopharyngeus nucleus. The fasciculus receives fibers from the facialis (intermedius), glossopharyngeus and vagus nerves. The fibers spread over the total extent of the fasciculus: the facialis fibers exhibit a preference for a dorsomedial position and the glossopharyngeusvagus fibers for a ventrolateral position. There are several interchanging fibers between the somatic sensory and visceral sensory projecting areas.The results indicate a close similarity between amphibian and mammalian brain stem motor nuclei and sensory projections, though some parts are present in a primordial form in the fro

ISSN:0092-7317    

DOI:10.1002/cne.901780109

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

年代:1978

数据来源: WILEY

摘要:

AbstractSeveral aspects of data collection and analyses of peripheral nerve experiments employing light and electron microscopic morphometric techniques have not been adequately discussed in the literature. From statistical tests performed on nerve data, it was found that light compared with electron microscopic morphometry underestimates the number of small fibers. An optimum sampling strategy must take into account a potential bias toward small fibers introduced by measuring fibers from electronmicrographs. It must also take into account a potential bias introduced by the non‐random distribution of nerve fibers of different sizes in nerves. These biases are offset by sampling a large enough number of fibers from large enough area electron micrographs. A method is presented for analysing peripheral nerve data using the nested analysis of variance. This requires first dividing the usual bimodal nerve fiber distribution into component normally distributed parts. The number of fibers in the two portions of a bimodal distribution must be considered in data analysis. Knowledge of the variances of parameters to be studied in any particular nerve is necessary for optimum sampling strategie

ISSN:0092-7317    

DOI:10.1002/cne.901780110

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

年代:1978

数据来源: WILEY

ISSN:0092-7317    

DOI:10.1002/cne.901780112

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

年代:1978

数据来源: WILEY