摘要:

AbstractDopamine and adenosine 3′:5′‐monophosphate (cAMP) regulated phosphoprotein of Mr32 kDa (DARPP‐32) and phosphatase inhibitor 1 (I‐1) have been associated with intracellular signal transduction processes and share several biochemical features. Localization of each phosphoprotein in distinct neural structures will aid investigation of their physiologic properties and help identify their unique roles in the nervous system. We have compared the distribution of the two phosphoproteins in the amygdala and hippocampus of the rhesus monkey with the aid of immunocytochemical procedures. Neurons immunoreactive to antibodies raised against the phosphoproteins DARPP‐32 and I‐1 were noted in the cortical, central, and components of the basal group, including the basomedial, the lateral, and to a lesser extent, the basolateral amygdaloid nuclei. Within the large basal nuclei positive neurons were found preferentially in their medial and ventral subdivisions. By making a direct comparison in the same animals, we observed differences in the distribution of the two phosphoproteins in the amygdala. DARPP‐32 and I‐1 positive neurons overlapped partially in the basal nuclei, to a lesser extent in the cortical, but were segregated in the central amygdaloid nucleus with neurons positive for DARPP‐32 noted laterally, and for I‐1 medially.In contrast to the amygdala, where numerous DARPP‐32 and I‐1 positive neurons were observed, only I‐1 had a notable presence in the hippocampus. Moreover, I‐1 associated label was found only in neurons in the granule cell layer of the dentate gyrus, their dendritic plexus, and axons which innervate hilar and CA3 neurons. DARPP‐32 and I‐1 are intracellular messengers associated with signal transduction. Their regional distribution in the amygdala and the hippocampus suggests an involvement in the level of excitability of specific components of these limbic structures. Moreover, our results suggest that I‐1 has a unique role in the intrinsic circuitry of the hippocampal formation and indicate a system where the physiologic properties of I‐1 may be studied

ISSN:0092-7317    

DOI:10.1002/cne.903340102

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

年代:1993

数据来源: WILEY

摘要:

AbstractNeuronal response properties vary markedly at increasing levels of the cortical hierarchy. At present it is unclear how these variations are reflected in the organization of the intrinsic cortical circuitry. Here we analyze patterns of intrinsic horizontal connections at different hierarchical levels in the visual cortex of the macaque monkey. The connections were studied in tangential sections of flattened cortices, which were injected with the anterograde tracer biocytin. We directly compared the organization of connections in four cortical areas representing four different levels in the cortical hierarchy. The areas were visual areas 1, 2, 4 and Brodman's area 7a (V1, V2, V4 and 7a, respectively). In all areas studied, injections labeled numerous horizontally coursing axons that formed dense halos around the injection sites. Further away, the fibers tended to form separate clusters. Many fibers could be traced along the way from the injection sites to the target clusters.At progressively higher order areas, there was a striking increase in the spread of intrinsic connections: from a measured distance of 2.1 mm in area V1 to 9.0 mm in area 7a. Average interpatch distance also increased from 0.61 mm in area V1 to 1.56 mm in area 7a. In contrast, patch size changed far less at higher order areas, from an average width of 230 m̈M in area V1 to 310 m̈m in area 7a. Analysis of synaptic bouton distribution along axons revealed that average interbouton distance remained constant at 6.4 m̈m (median) in and out of the clusters and in the different cortical areas. Larger injections resulted in a marked increase in the number of labeled patches but only a minor increase in the spread of connections or in patch size.Thus, in line with the more global computational roles proposed for the higher order visual areas, the spread of intrinsic connections is increased with the hierarchy level. On the other hand, the clustered organization of the connections is preserved at higher order areas. These clusters may reflect the existence of cortical modules having blob‐like dimensions throughout macaque monkey visual cortex. © 1993 Wiley‐Li

ISSN:0092-7317    

DOI:10.1002/cne.903340103

出版商:Wiley‐Liss, Inc.    

年代:1993

数据来源: WILEY

摘要:

AbstractA polyclonal antibody raised against nicotinic acetylcholine receptor protein from purified locust neuronal membrane was used to analyse the distribution of antigenic sites within the central nervous system of adultSchistocerca gregaria. Light microscopic examination showed that all principal neuropiles in the thoracic ganglia label with the antibody but that the major tracts and commissures do not. Analysis of this pattern of staining in the electron microscope reveals that the receptor is present on specific synaptic and extrajunctional neuronal membranes in the neuropile. Antigenic sites are also evident on the plasma membranes and within the cytoplasm adjacent to Golgi complexes of some neuronal somata, suggesting that these neurones synthesise nicotinic acetylcholine receptors. In addition to neuronal labelling, there is evidence that the receptor is also present on the membranes of three types of glial cells. The implications of this pattern of receptor distribution are discussed. © 1993 Wiley‐Liss, I

ISSN:0092-7317    

DOI:10.1002/cne.903340104

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

年代:1993

数据来源: WILEY

摘要:

AbstractCalbindin‐D28k(CaBP) is a calcium‐binding protein that is prominent in various parts of the mammalian auditory system. In order to shed some light on the possible role of CaBP during ontogeny, when calcium ions play key roles in several processes, the location of CaBP was examined immunocytochemically in the auditory system of the developing rat. This study focuses on the principal nuclei of the superior olivary complex, which show distinct CaBP labeling in the adult. Consistent with previous reports in the rat and other mammals, CaBP immunoreactivity in adults was intense in somata of the medial nucleus of the trapezoid body (MNTB) and in the neuropil (presumably in axons) of the lateral superior olive (LSO), the superior paraolivary nucleus (SPN), and the medial superior olive (MSO). In fetal and neonatal animals, however, the labeling pattern was strikingly different. Around birth, MNTB neurons are immunonegative for CaBP, whereas somata and processes in the LSO, probably neuronal, are heavily labeled at that age. This labeling pattern persists throughout the first week of postnatal life and begins to change at P8, when MNTB neurons become immunopositive for CaBP. During the next 10 days labeling intensity in MNTB neurons increases considerably, and the increase is paralleled by an increase in labeling intensity of the neuropil in the LSO, SPN, and MSO, indicating that the labeled processes in these nuclie may be axons originating from MNTB neurons. Immunoreactivity in LSO cells begins to decline around P8, decays rapidly between P10 and P18, and reaches its adult level around P28, when the CaBP labeling pattern in the whole superior olivary complex is indistinguishable from that in the adult.The present results show that the development of CaBP immunoreactivity in the rat superior olivary complex is characterized by two reciprocally related processes: as immunoreactivity within MNTB somata and fibers in the SPN, the LSO, and the MSO increases between P8 and about P21, the immunoreactivity in LSO neurons declines. CaBP immunoreactivity in LSO neurons is only transiently present, suggesting a critical period in development during which the control of Ca2+homeostasis in LSO neurons may be of particular importance. © 1993 Wiley‐Lis

ISSN:0092-7317    

DOI:10.1002/cne.903340105

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

年代:1993

数据来源: WILEY

摘要:

AbstractPrevious work has associated the proto‐oncogene c‐foswith such events as neuronal excitation and cell growth and differentiation. This study specifically examined the expression of the Fos protein as well as other Fos‐related antigens (Fras) during postnatal development of rat brain. Ages P1 through P15 as well as adult animals (P60) were examined. Particular focus was placed on developing cerebral cortex, striatum, hippocampus, and cerebellum. We used both the Alu antiserum, which recognizes the Fos protein specifically, and the M5 antiserum, which recognizes both Fos and a family of Fos‐related antigens.Fos and Fras were developmentally regulated in a region‐ and cell‐specific manner. Differential nuclear and cytoplasmic labeling appeared age dependent. Transient Fos expression was generally followed by a more protracted time course of Fra expression. Fos and a delayed or an extended expression of Fras were observed in subplate neurons between P1 and P15, in striatal striosome and matrix neurons between P1 and P9, and in hippocampal pyramidal neurons between P1 and P9. Fras alone were expressed in cerebral cortex pyramidal neurons and other cortical neurons between ages P1 and P15. Fos and Fras were concomitantly expressed in piriform and entorhinal cortical neurons between P1 and P9 and in cerebellar Purkinje cells between ages P5 and P10. Constitutive levels of Fos and Fras remained detectable in adult animals in a subset of cerebral cortical neurons and cerebellar Purkinje neurons. © 1993 Wil

ISSN:0092-7317    

DOI:10.1002/cne.903340106

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

年代:1993

数据来源: WILEY

摘要:

AbstractAn antibody to MAP2 was used on sections through the posteromedial barrel subfield (PMBSF) of primary somatosensory cortex to reveal the distributions of cell bodies and dendrites. It was found that apical dendrites of layer VI neurons form irregular bundles or sheets that break up in layer IV, where most of these dendrites form their terminal tufts. In contrast, the apical dendrites of layer V pyramidal neurons form clusters that ascend into layer II/III where they are joined by apical dendrites of the superficial pyramidal neurons. In layer IV the clusters of the layer V apical dendrites are more concentrated in barrel walls than in hollows. Thus, in layer IV the average center to center spacing between the clusters is about 25 m̈m in the barrel hollows, and about 22 m̈m in the barrel walls. In part, this differential distribution of the apical dendritic clusters is brought about because the apical dendrites of layer V pyramids beneath the periphery of the barrel hollows arc towards the barrel walls as they pass from layer V into layer IV.Based on previous analyses of the three‐dimensional organization of the primary visual areas in the monkey, cat, and rat, it has been proposed that neurons in these cortices are organized into modules that are centered on the clusters of apical dendrites belonging to layer V pyramidal neurons. Mouse PMBSF cortex is composed of similar pyramidal cell modules and the organization of neurons in these modules is similar to that in visual cortex. This suggests that the pyramidal cell modules are fundamental neuronal units that exist throughout the cerebral cortex, and implies that the various functional areas of the cortex in different species are organized according to a common, basic plan. © 1993 Wiley‐Lis

ISSN:0092-7317    

DOI:10.1002/cne.903340107

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

年代:1993

数据来源: WILEY

摘要:

AbstractIn order to assess the ability of sharks and rays to sense pain, the proportion of myelinated versus unmyelinated sensory fibres in the dorsal roots and the diameter spectrum of cells in the dorsal root ganglia of three species of elasmobranch fish were ascertained. Electron micrographs were used to count the numbers of myelinated and unmyelinated fibres in montages of whole dorsal roots of the long‐tailed stingray (Himantura sp.), the shovelnose ray (Rhinobatus battilum), and small specimens of the black‐tip shark (Carcharhinus melanopterus). The diameters of dorsal root ganglion cells in each species were measured by using the light microscope. Less than 1% of the dorsal root axons in the long‐tailed stringray and a large specimen of the shovelnose were unmyelinated, whereas in smaller shovelnose rays and in the small black‐tipped sharks, from 14% to 38% of axons were unmyelinated. Unmyelinated fibres differed from those in mammalian nerves in that there was a one‐to‐one association of the fibre with a Schwann cell. We conclude from these observations that myelination was incomplete in the black‐tipped sharks and the smaller specimens of the shovelnose rays. The distribution of the diameter of cells of the dorsal root ganglia of these species was unimodal, resembling the diameter range that has been reported for the somata of myelinated fibres in the cat. We interpret these results as indications that sharks and rays lack the neural apparatus essential for the sensation of pain and we suggest that, to these life forms, the perception of pain might have little relevance to survival. © 1993 W

ISSN:0092-7317    

DOI:10.1002/cne.903340108

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

年代:1993

数据来源: WILEY

摘要:

AbstractThe distribution and targets of nerves containing the adrenergic markers tyrosine hydroxylase, dopamine β‐hydroxylase, and neuropeptide Y in the human olfactory mucosa were investigated by immunohistochemistry. Tissue was obtained at autopsy from the nasal cleft of 16 adults ranging in age from 24 to 90 years, and from one spontaneously aborted 16‐week‐old fetus. The presence of olfactory receptor neurons in nasal mucosa was confirmed by staining with the antibody to olfactory marker protein. Targets of adrenergic innervation were blood vessels, including the vasa nervorum within the sheaths of olfactory nerve bundles, and Bowman's glands in the lamina propria. Adrenergic fibers penetrated the adventitia of blood vessels and terminated near the media, and were in close proximity to Bowman's glands but did not enter the acini. In the fetal tissue, the vasa nervorum were the major targets of adrenergic fibers. Age‐related differences in the pattern and statistically significant differences in the density of innervation of blood vessels were noted between adults under and over 60 years of age. In the younger group, plexuses of nerve fibers containing colocalized dopamine β‐hydroxylase and neuropeptide Y occurred adjacent to arterioles and large bundles of fibers adjacent to venules; in older individuals, few fiber plexuses occurred adjacent to arterioles and thin bundles of fibers adjacent to venules. The distribution of adrenergic innervation suggests that vasomotor tone and secretion are regulated by adrenergic nerves. The decrease in adrenergic innervation in older individuals, with resultant effects on perireceptor processes, may be associated with age‐related declines in olfactory function. © 1993 W

ISSN:0092-7317    

DOI:10.1002/cne.903340109

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

年代:1993

数据来源: WILEY

摘要:

AbstractAxons immunoreactive for calcitonin gene‐related peptide (CGRP) and substance P are present in the olfactory nerve, although few, if any, olfactory receptor cells contain immunocytochemically detectible levels of these peptides. The possible trigeminal origin of these fibers was tested by performing unilateral stereotaxic lesions of the ophthalmic division of the trigeminal nerve, followed 2–25 days later by immunocytochemistry for CGRP and substance P. As reported previously, free nerve endings immunoreactive for both peptides were found transversing the nasal epithelium on the unlesioned side. Also on the unlesioned side, peptidergic axons, immunoreactive for both CGRP and substance P, could be traced from the olfactory nerve into the glomerular layer throughout the olfactory bulb, but especially into its rostral third. Ipsilateral to the trigeminal ganglion lesion, such peptide‐immunoreactive fibers were absent or markedly reduced in the bulb, nerve, and epithelium. These results indicate that the peripheral branches of the ophthalmic branch of the trigeminal nerve enter the olfactory bulb along with the olfactory nerve and terminate in the glomerular layer along with the olfactory axons. Ultrastructural analysis of the CGRP‐immunoreactive terminals in the glomeruli reveal vesicle‐filled axonal processes terminating in the absence of obvious pre‐ or postsynaptic specializations. Whether the trigeminal fibers in the bulb are functional, e.g., convey information to the olfactory bulb via an axon reflex, or relay information from the olfactory bulb to the brainstem trigeminal nuclei is unclear. © 1993 Wil

ISSN:0092-7317    

DOI:10.1002/cne.903340110

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

年代:1993

数据来源: WILEY

摘要:

AbstractIn macaque monkeys, lesions involving the posterior portion of the inferior temporal cortex, cytoarchitectonic area TEO, produce a severe impairment in visual pattern discrimination. Recently, this area has been shown to contain a complete, though coarse, representation of the contralateral visual field (Boussaoud, Desimone, and Ungerleider: J. Comp. Neurol. 306:554–575, '91). Because the inputs and outputs of area TEO have not yet been fully described, we injected a variety of retrograde and anterograde tracers into 11 physiologically identified sites within TEO of seven rhesus monkeys and analyzed the areal and laminar distribution of its cortical connections.Our results show that TEO receives feedforward, topographically organized inputs from prestriate areas V2, V3, and V4. Additional sparser feedforward inputs arise from areas V3A, V4t, and MT. Each of these inputs is reciprocated by a feedback projection from TEO. TEO was also found to have reciprocal intermediate‐type connections with the fundus of the superior temporal area (area FST), cortex in the most posteromedial portion of the superior temporal sulcus (the posterior parietal sulcal zone [area PP]), cortex in the intraparietal sulcus (including the lateral intraparietal area [area LIP]), the frontal eye field, and area TF on the parahippocampal gyrus. The connections with V3A, V4t, and PP were found only after injections in the peripheral field representations of TEO. Finally, TEO was found to project in a feedforward pattern to area TE and to areas anterior to FST on the lateral bank and floor of the superior temporal sulcus (areas TEm, TEa, and IPa, Seltzer and Pandya: Brain Res. 149:1–24, '78), all of which send feedback projections to TEO. Feedback projections also arise from parahippocampal area TH, and areas TG, 36, and possibly 35. These are complemented by only sparse feedforward projections to TG from central field representations in TEO and to TH from peripheral field representations.The results thus indicate that TEO forms an important link in the occipitotemporal pathway for object recognition, sending visual information forward from V1 and prestriate relays in V2–V4 to anterior inferior temporal area TE. © 1993 Wiley‐Liss, Inc.This article is a US Goveriiment work and, as such, is in the public domain in the United States

ISSN:0092-7317    

DOI:10.1002/cne.903340111

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

年代:1993

数据来源: WILEY