摘要:

AbstractThe present study examined, in Nembutal‐anesthetized and artificially ventilated cats, the morphologic properties of the inspiratory neurons of the ventral respiratory group (VRG). Horseradish peroxidase (HRP) was injected into 21 augmenting inspiratory or late inspiratory neurons with peak firing rates in the late inspiratory phase. The majority of the stained neurons were antidromically activated by stimulation of the cervical cord. Thirteen somata, located within or around the nucleus ambiguus (AMB), between 100 μm caudally and 2,000 μm rostrally to the obex, were stained. In ten cases, the stem axons issuing from the cells of origin coursed medially to cross the midline without giving off any axonal collaterals. Three neurons gave rise to axonal collaterals on the ipsilateral side, distributing boutons in the medullary reticular formation, in the vicinity of the AMB, hypoglossal nucleus, solitary tract, and dorsal motor nucleus of the vagus. In eight neurons, only the axons were labeled; in four of these, which were antidromically activated from the spinal cord, the stem axons crossed the midline 2,000‐3,000 μm rostral to the obex and descended in the reticular formation around the AMB down to the cervical cord. They issued several axonal collaterals, distributing terminal boutons at the level of the caudal end of the retrofacial nucleus and about 1,000 μm rostral and caudal from the obex. Terminals were found mainly in and around the AMB, and a few were found in the vicinity of the dorsal motor nucleus of the vagus. The remaining four nonactivated axons distributed their terminal boutons widely in the reticular formation around the AMB. Thus, the augmenting inspiratory neurons of the VRG were shown to project not only to the spinal cord, but also to the VRG, hypoglossal nucleus, and dorsal motor nucleus of th

ISSN:0092-7317    

DOI:10.1002/cne.902820202

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

年代:1989

数据来源: WILEY

摘要:

AbstractMultiunit microelectrode recordings and injections of horseradish peroxidase (HRP) were used to reveal neuron response properties, somatotopic organization, and interconnections of somatosensory cortex in the lateral sulcus (sylvian fissure) of New World owl monkeys. There were a number of main findings. (1) Representations of the face and head in areas 3b, 1, and S‐II are found on the upper bank of the lateral sulcus. Most of the mouth and lip representations of area 3b were found in a rostral extension along the lip of the lateral sulcus. Adjacent cortex deeper in the lateral sulcus represented the nose, eye, ear, and scalp. (2) S‐II was located on the upper bank of the lateral sulcus and extended past the fundus onto the deepest part of the lower bank. The face was represented most superficially in the sulcus, with the hand, foot, and trunk located in a rostrocaudal sequence deeper in the sulcus. The orientation of S‐II is “erect,” with the limbs pointing away from area 3b. (3) Neurons in S‐II were activated by light tactile stimulation of the contralateral body surface. Receptive fields were several times larger than for area 3b neurons. (4) A 1‐2‐mm strip of cortex separating the face and hand representations in S‐II was consistently responsive to the stimulation of deep receptors but was unresponsive to light cutaneous stimulation. (5) Injections of horseradish peroxidase in the electrophysiologically identified hand or foot representations of area 3b revealed somatotopically matched interconnections with mapped hand and foot representations in S‐II. (6) A systematic representation of the body, termed the “ventral somatic” area, VS, was found extending laterally from S‐II on the lower bank of the lateral sulcus. Within VS, the hand and foot were represented deep in the sulcus along the hand and foot regions of S‐II, and the face was lateral near the ventral lip of the sulcus. (7) Neurons at most recording sites in the VS region were activated by contralateral cutaneous stimuli. However, a few sites had neurons with bilateral receptive fields. Receptive field sizes were comparable to those in S‐II. In addition, neurons in islands of cortex in the VS region had properties that suggested that they were activated by pacinian receptors, while other regions were difficult to activate by light tactile stimuli but responded to stimuli that would activate deep receptors. (8) A few recording sites caudal to S‐II on the upper bank of the lateral sulcus were responsive to somatic stimuli. (9) Finally, some recording sites rostral to S‐II in the vicinity of the granular insular region were responsive to cutaneous stimuli. This cortex had sparse interconnections with area 3b. Overall the results provide a detailed understanding of how the face and head are represented in the lateral part of area 3b, reveal body surface representations in S‐II and an adjoining ventral somatic field (VS), locate neurons with pacinianlike features in or about VS, and demonstrate somatotopic interconnections be

ISSN:0092-7317    

DOI:10.1002/cne.902820203

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

年代:1989

数据来源: WILEY

摘要:

AbstractA monoclonal antibody that recognizes a nonphosphorylated epitope on the 168 kDa and 200 kDa subunits of neurofilament proteins has been used in an immunohistochemical study of cynomolgus monkey (Macaca fascicularis) and human neocortex. This antibody, SMI‐32, primarily labels the cell body and dendrites of a subset of pyramidal neurons in both species. A greater proportion of neocortical pyramidal neurons were SMI‐32 immunoreactive (ir) in the human than in the monkey. SMI‐32‐ir neurons exhibited consistent differences in the intensity of their immunoreactivity that correlated with cell size. The cellular specificity of SMI‐32 immunoreactivity suggests that a subpopulation of neurons can be distinguished on the basis of differences in the molecular characteristics of basic cytoskeletal elements such as neurofilament proteins.The size, density, and laminar distribution of SMI‐32‐ir neurons differed substantially across neocortical areas within each species and between species. Differences across cortical areas were particularly striking in the monkey. For example, the anterior parainsular cortex had a substantial population of large SMI‐32‐ir neurons in layer V and a near absence of any immunoreactive neurons in the supragranular layers. This contrasted with the cortical area located more laterally on the superior temporal gyrus, where layers III and V contained substantial populations of large SMI‐32‐ir neurons. Both areas differed significantly from the posterior inferior temporal gyrus, which was distinguished by a bimodal distribution of large SMI‐32‐ir neurons in layer III. Differences across human areas were less obvious because of the increase in the number of SMI‐32‐ir neurons. Perhaps the most notable differences across human areas resulted from shifts in the density of the larger SMI‐32‐ir neurons in deep layer III. A comparison between the species revealed that isocortical areas exhibited greater differences in their representation of SMI‐32‐ir neurons than primary sensory or transitional cortical areas. A comparison of distribution patterns of SMI‐32‐ir neurons across monkey cortical areas and data available on the laminar organization of cortical efferent neurons suggests that a common anatomic characteristic of this chemically identified subpopulation of neurons is that they have a distant axonal projection. Such correlations of cell biological characteristics with specific elements of cortical circuitry will further our understanding of the molecular and cellular properties that are critically linked to a given neuron'

ISSN:0092-7317    

DOI:10.1002/cne.902820204

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

年代:1989

数据来源: WILEY

摘要:

AbstractThe distribution of calcitonin gene‐related peptide (CGRP) in the cat nucleus ambiguus was examined by means of a combination of horseradish peroxidase (HRP) tracing and immunohistochemical techniques. Vagal motoneurones in the nucleus ambiguus were identified by applying HRP to either the thoracic vagus or the superior laryngeal nerve or the cervical vagus.Motoneurones in the nucleus ambiguus labelled with HRP from the thoracic vagus did not contain CGRP‐like immunoreactivity although CGRP‐like immunoreactive cells were present in this nucleus on the same sections. In contrast, a large proportion of the motoneurones labelled from the superior laryngeal nerve and a smaller proportion of cells labelled from the cervical vagus did contain CGRP‐like immunoreactivity.It is concluded that CGRP‐like immunoreactivity is absent from vagal preganglionic motoneurones projecting to structures in the thorax and abdomen but is present in vagal motoneurones projecting to striated muscle of the larynx an

ISSN:0092-7317    

DOI:10.1002/cne.902820205

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

年代:1989

数据来源: WILEY

摘要:

AbstractThe early postnatal development of neurons containing vasoactive intestinal polypeptide (VIP) and peptide histidine isoleucine (PHI) has been analyzed in visual areas 17 and 18 of cats aged from postnatal day (P) 0 to adulthood. Neuronal types are established mainly by axonal criteria. Both peptides occur in the same neuronal types and display the same postnatal chronology of appearance. Several cell types are transient, which means that they are present in the cortex only for a limited period of development. According to their chronology of appearance the VIP/PHI‐immunoreactive (ir) cell types are grouped intothreeneuronal populations.The first population comprises six cell types which appear early in postnatal life. Thepseudohorsetailcells of layer I possess a vertically descending axon which initially gives rise to recurrent collaterals, then forms a bundle passing layers III to V, and finally, horizontal terminal fibers in layer VI. The neurons differentiate at P 4 and disappear by degeneration around P 30. Theneurons with columnar dendritic fieldsof layers IV/V are characterized by a vertical arrangement of long dendrites ascending or descending parallel to each other, thus forming an up to 600 μm long dendritic column. Their axons always descend and terminate in broad fields in layer VI. The neurons appear at P 7 and are present until P 20. Themultipolar neurons of layerVI occur in isolated positions and have broad axonal territories. The neurons differentiate at P 7 and persist into adulthood.Bitufted to multipolar neurons of layersII/III have axons descending as a single fiber to layer VI, where they terminate. The neurons appear at P 12 and persist into adulthood. The four cell types described above issue a vertically oriented fiber architecture in layers II‐V and a horizontal terminal plexus in layer VI which is dense during the second, third and fourth week. Concurrent with the disappearance of the two transient types the number of descending axonal bundles and the density of the layer VI plexus is reduced, but the latter is maintained during adulthood by the two persisting cell types.Two further cell types belong to thefirst population: Thetransient bipolar cellsof layers IV, V, and VI have long dendrites which extend through the entire cortical width. Their axons always descend, leave the gray matter, and apparently terminate in the upper white matter. The neurons differentiate concurrently with the pseudohorsetail cells at P 4, are very frequent during the following weeks, and eventually disappear at P 30. Thepersisting bipolar cellsof layers II/III and IV have shorter dendrites and issue a diffuse axon plexus which largely remains intralaminarly. The neurons are recognizable from P 12 and persist, although in the adult cat cortex they are rare.The second population comprises two cell types. Theneurons with uertically descending main axon and horizontal collaterals of layersII/III and IV form diffuse axon plexuses by means of horizontal and oblique collaterals. They seem to terminate in the form of en passant boutons on pyramidal cell bodies. The neurons appear a t P 18 and persist into adulthood. The neurons of layerIhave broad dendritic fields and unconspicuous short axons which diffusely distribute in superficial layers. The cells are recognizable from P 25 onwards. The appearance of the second population initiates a change from the so far vertically organized architecture to a more diffuse innervation pattern. The change is complete when the transient innervation patterns have become superseded during the second postnatal month by thebasket cellsof layers II/III and IV, which constitute the third population. These neurons by far outnumber all other cell types and, until the end of the second month, fill these layers with a dense terminal plexus. Thereafter, the number of somata and the terminal density is reduced in layer IV, so that in adult animals most neurons and the densest plexus reside in layers II/III. The innervation now is less dense in layer IV and only loose in deeper cortical layers.In summary, transient VIP‐ and PHI‐ir cell types dominate the early postnatal cortex. They form a largely vertical fiber architecture, and degener‐ ate and become eliminated by probably cell death around the end of the first month. Concurrently with their disappearance and during the second postnatal month, the persisting cell types form a completely different innervation pattern which reaches an adult state late p

ISSN:0092-7317    

DOI:10.1002/cne.902820206

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

年代:1989

数据来源: WILEY

摘要:

AbstractEnzyme‐histochemical methods for thiamine pyrophosphatase (TPPase) and nucleoside diphosphatase (NDPase) were applied to wholemounted rabbit retinae to demonstrate the shape and distribution of microglial cells in early postnatal and adult animals. At birth, microglial cells were already present in the entire retina. They acquired their adult “resting shape” during the first 3 postnatal weeks. Early postnatally labeled microglial cells were scattered throughout the nerve fiber layer, the inner plexiform layer, and the outer plexiform layer (OPL); at adulthood, they were not detected in the OPL. Nissl‐stained retinae revealed that the number of microglial cells continuously increased during postnatal development. The same Nissl‐stained preparations were used to evaluate the topography of degenerating cells in the developing postnatal retina of the rabbit. Large numbers of degenerating pyknotic cells were observed throughout the entire retinal ganglion cell layer during the first postnatal week. Later their number decreased, and from the third postnatal week onward degenerating cells were rare. Also discussed is that the emergence of microglial cells during development may be related to cell death, whereas at adulthood the function(s) of microglial cells remains obscure.Evidence for the blood‐derived origin of microglia was not obtained in this study. It is argued here that if this mode of development, which has been demonstrated for other species, is also applied to the rabbit retina, then microglia would have to migrate over considerable distances, since, postnatally, the rabbit retina is avascular for more

ISSN:0092-7317    

DOI:10.1002/cne.902820207

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

年代:1989

数据来源: WILEY

摘要:

AbstractThe superior cervical ganglion of rats contains a considerable number of nerve fibers with GABA‐like immunoreactivity which show a nonuniform distribution within the ganglion. The topography of these fibers has been analyzed by using antibodies raised against GABA‐BSA‐glutaraldehyde complexes. GABA‐postive axons and axon varicosities accumulated around a subpopulation of principal ganglion cells forming basketlike patterns. These neurons richly innervated by GABA‐positive axons (RIG‐neurons) in turn were aggregated in patches with strong immunoreactivity. The size and packing desity of the patches containing RIG‐neurons and GABA‐positive axons approaching them had rostral‐to‐caudal and medial‐to‐lateral gradients. Similar patterns were found in right and left ganglia. In five ganglia, a quantitative analysis revealed on average 1,344 RIG‐neurons per ganglion representing about 5% of the total neuron population, with small variations (standard deviation 122) despite the highly variable shape of the ganglia. The distribution of RIG‐neurons resembles that of neurons sending their axons into the internal carotid nerve. To check this possible correlation, HRP was injected into the eye and applied to the transected external carotid nerve. Double staining for the retrogradely transported peroxidase and GABA immunohistochemistry revealed that RIG‐neurons formed a small subpopulation of retrogradely labelled neurons in both experiments. This suggests that RIG‐neurons innervate various target organs. This conclusion is in agreement with the observation that RIG‐neurons also exist in other sympathetic ganglia. Data presented suggest that sympathetic ganglion cells can be classified on the basis of non‐uniform innervation patterns formed by axons t

ISSN:0092-7317    

DOI:10.1002/cne.902820208

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

年代:1989

数据来源: WILEY

摘要:

AbstractThe distribution of retrogradely labeled cerebellar nucleocortical (NC) cells and anterogradely labeled corticonuclear (CN) fibers was investigated in a prosimian primate (Galago) by means of horseradish peroxidase as a tracer. Iontophoretic and pressure injections were made in the cortex of lobule V and the resultant patterns of label were determined in the cerebellar nuclei. Following iontophoretic injections in vermal (zone A), intermediate (zones C1, C3), and lateral (zone D) cortices, retrogradely labeled cells were present in medial (NM), anterior interposed (NIA), and lateral (NL) cerebellar nuclei, respectively. Larger injections that involved A‐C2zones resulted in NC label in NM, medial NIA, and throughout the posterior interposed (NIP) nucleus. Retrogradely labeled NC cells were usually found in areas of their respective nuclei that also contained anterogradely filled CN axons. In addition, retrogradely labeled cells were seen contralateral to some injections. Contralateral NC cells were found mainly in the NM and NIP and seemed to be labeled in response to injections that involved zones A, C2, and possibly x on the opposite side. No contralateral CN labeling was seen. It appears that the NC projections of lobule V follows a basic zonal (sagittal) orientation and that most are reciprocal to CN fibers arising from the same cortical area.There is evidence of zonal heterogeneity in the ipsilateral NC projection. Iontophoretic injections placed in adjacent zones resulted in markedly different numbers of retrogradely labeled NC cells in their respective nuclei. Also, after pressure injections that involved two or more adjoining zones, the number of labeled NC cells was large in one nucleus but minimal in an adjacent nucleus. These data suggest that different cerebellar cortical zones have quantitatively different NC input; this may relate to specific functional demands placed on each nucleus and its corresponding cortical zone.On the basis of their known connections, it is hypothesized that there are at least three and possibly four categories of NC cells.Ipsilateral reciprocal NC cellsare found in, or on the periphery of, CN terminal fields formed by axons originating from the same cortical area to which the NC cells project.Ipsilateral nonreciprocal NC cellsare located outside the CN terminal field and may even be found in an adjacent nucleus; these are fewer in number than the reciprocal population.Contralateral NC cellsare found in the opposite cerebellar nuclei and appear to be topographically related to the ipsilateral contingent as well as to the injection site. It is probable that different types of NC cells have individualized functional characteristic

ISSN:0092-7317    

DOI:10.1002/cne.902820209

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

年代:1989

数据来源: WILEY

摘要:

AbstractIn macaque monkeys with injections of tritiated amino acids or horseradish peroxidase in the ventrolateral granular frontal cortex, we observed extensive anterograde and retrograde labeling of the premotor and somatosensory cortex in and around the lateral sulcus. Comparable labeling was not present with large and small control injections of the dorsal granular cortex. Cytoarchitectonic evaluation of the perisylvian cortex in the three cases examined in detail indicated that labeled areas included the ventral premotor cortex (area 6V); the precentral opercular and orbitofrontal opercular areas (PrCO and OFO); the second somatosensory area (S‐II); the opercular cortex immediately anterior to S‐II, possibly corresponding to area 2 of the S‐I complex; and the central part of the insular cortex, including portions of the granular and dysgranular insular fields (Ig, Idg). Labeling was particularly dense and extensive in areas 6V, S‐II, and OFO. Lighter labeling was also present in the rostral inferior parietal lobule (areas 7b and POa).The distribution of label within perisylvian areas was not uniform: certain parts were heavily labeled, while other parts were lightly labeled or unlabeled. Comparison of label distribution with published accounts of the somatotopy of these areas indicates that forelimb and orofacial representations were selectively labeled. Further, our results, taken together with other recent anatomical findings (e.g., Matelli et al.:Journal of Comparative Neurology251:281‐298, 1987; Barbas and Pandya:Journal of Comparative Neurology256:211‐228, 1987) suggest strongly that there is a network of interconnected forelimb and orofacial representations in macaque cortex, involving the ventral granular frontal cortex, area 6V, OFO, opercular area 2, S‐II, the central insula, and area 7b.Each injection of frontal cortex which labeled the perisylvian somatic cortex involved the cortex of the ventral rim of the principal sulcus (PSvr). The cortex surrounding the PSvr does not stand out as a distinct area in Nisslstained material. However, examination of myelin‐stained sections prepared from uninjected hemispheres with the Gallyas technique revealed the existence of a distinct zone centered on the PSvr. This myeloarchitectonic area, which we term area 46vr, is more heavily myelinated than the ventral bank and fundus of the principal sulcus (area 46v) but is less heavily myelinated than the ventral (inferior) convexity (area 12). Involvement of area 46vr in our injections was probably responsible for the strong labeling observed in perisylvian somatic areas. However, we cannot exclude the possibility that adjacent areas, such as the anterior part of area 12, also possess somatic connections.It is clear from these results that ventral granular frontal has strong reciprocal connections with perisylvian somatic areas. Among these areas, S‐11, Ig, and Idg have been suggested as higher‐order centers in a tactile recognition pathway (Friedman et al.:Journal of Comparative Neurology252:323‐347, 1986), and area 6V appears to have a role in the control of prehensive movements of the hands and mouth (Rizzolatti et al.:Experimental Brain Research67:220‐224, 1987). By analogy to other granular frontal areas, the ventral granular frontal cortex may contain a working memory mechanism which enables animals to remember the tactile characteristics of recently encountered objects and command the mouth and forelimb movements appropriate for

ISSN:0092-7317    

DOI:10.1002/cne.902820210

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

年代:1989

数据来源: WILEY

ISSN:0092-7317    

DOI:10.1002/cne.902820201

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

年代:1989

数据来源: WILEY