ISSN:0092-7317    

DOI:10.1002/cne.903270402

出版商:Wiley‐Liss, Inc.    

年代:1993

数据来源: WILEY

摘要:

AbstractThe cortical connections of the primary somatosensory area (SI or 3b), a caudal somatosensory field (area 1/2), the second somatosensory area (SII), the parietal ventral area (PV), the ventral somatosensory area (VS), and the lateral parietal area (LP) were investigated in grey headed flying foxes by injecting anatomical tracers into electrophysiologically identified locations in these fields. The receptive fields for clusters of neurons were mapped with sufficient density for injection sites to be related to the boundaries of fields, and to representations of specific body parts within the fields. In all cases, cortex was flattened and sectioned parallel to the cortical surface. Sections were stained for myelin and architectonic features of cortex were related to physiological mapping and connection patterns. We found patterns of topographic and montopographic connections between 3b and adjacent anterior parietal fields 3a and 1/2, and fields caudolateral to 3b (SII and PV). Area 1/2 had both topographic and nontopographic connections with 3b, PP, and SII. Connections of SII and PV with areas 3b, 3a, and 1/2 were roughly topographic, although there was clear evidence for nontopographic connections between these fields. SII was most densely connected with area 1/2, while PV was most densely connected with 3b. SII had additional connections with fields in lateral parietal cortex and with subdivisions of motor cortex. Other connections of PV were with subdivisions of motor cortex and pyriform cortex. Laminar differences in connection patterns of SII and PV with surrounding cortex were also observed. Injections in the ventral somatosensory area revealed connections with SII, PV, area 1/2, auditory cortex, entorhinal cortex, and pyriform cortex. Finally, the lateral parietal field had very dense connections with posterior parietal cortex, caudal temporal cortex, and with subdivisions of motor cortex. Our results indicate that the 3b region is not homogeneous, but is composed of myelin dense and light regions, associated with 3b proper and invaginations of area 1/2, respectively. Connections of myelin dense 3b were different from invaginating portions of myelin light area 1/2. Our findings that 3b is densely interconnected with PV and moderately to lightly interconnected with SII supports the notion that SII and PV have been confused across mammals and across studies. Our connectional evidence provides further support for our hypothesis that area 1/2 is partially incorporated in 3b and has led to theories of the evolution of cortical fields in mammals. © 1993 Wiley‐Liss, I

ISSN:0092-7317    

DOI:10.1002/cne.903270403

出版商:Wiley‐Liss, Inc.    

年代:1993

数据来源: WILEY

摘要:

AbstractSynapsin I is the best characterized member of a family of neuron‐specific phosphoproteins thought to be involved in the regulation of neurotransmitter release. In this report, we present the first extensive in situ hybridization study detailing the regional and cellular distribution of synapsin I mRNA in the adult rat brain. Both the regional distribution and relative levels of synapsin I mRNA established by in situ hybridization were confirmed by RNA blot analysis. Our data demonstrate the widespread yet regionally variable expression of synapsin I mRNA throughout the adult rat brain. The greatest abundance of synapsin I mRNA was found in the pyramidal neurons of the CA3 and CA4 fields of the hippocampus, and in the mitral and internal granular cell layers of the olfactory bulb. Other areas abundant in synapsin I mRNA were the layer II neurons of the piriform cortex and layer II and V neurons of the entorhinal cortex, the granule cell neurons of the dentate gyrus, the pyramidal neurons of hippocampal fields CA1 and CA2, and the cells of the parasubiculum. In general, the pattern of expression of synapsin I mRNA paralleled those encoding other synaptic terminal‐specific proteins, such as synaptophysin, VAMP‐2, and SNAP‐25, with noteworthy exceptions. To determine specificall how synapsin I mRNA levels are related to levels of synapsin I protein, we examined in detail the local distribution patterns of both synapsin I mRNA and protein in the rat hippocampus. These data revealed differential levels of expression of synapsin I mRNA and protein within defined synaptic circuits of the rat hippocampus. © 1993 Wiley

ISSN:0092-7317    

DOI:10.1002/cne.903270404

出版商:Wiley‐Liss, Inc.    

年代:1993

数据来源: WILEY

摘要:

AbstractThe vestibular primary afferent projection to the cerebellum of the rabbit was studied with retrograde and orthograde tracers. We injected individual lobules of the cerebellum with horseradish peroxidase (HRP) or wheat germ agglutinin‐HRP (WGA‐HRP). Following these injections the numbers of labeled and unlabeled cells in Scarpa's ganglion were counted. Approximately 64–89% of the cells in Scarpa's ganglion were labeled retrogradely following uvula‐nodular injections. About 2% of the cells in the ipsilateral Scarpa's ganglion were labeled after injections of the flocculus. Virtually no cells were labeled following injections of the ventral paraflocculus.The vestibular primary afferent projection to the uvula‐nodulus is so extensive that it must be part of a collateral system that also innervates the vestibular nuclei. This collateral projection pattern was confirmed by using fluorescent tracers injected into the uvula‐nodulus and vestibular complex. Fluorogold was injected into the uvula‐nodulus and peroxidaserhodamine isothiocyanate was injected into the vestibular complex. More than 50% of the neurons in Scarpa's ganglion were double labeled by these subtotal injections.The dense vestibular primary afferent projection to the uvula‐nodulus was confirmed by using the C fragment of tetanus toxin (TTC) injected into the labyrinth as an orthograde tracer. With the TTC technique, the vestibular primary afferent projection to the uvula‐nodulus terminated exclusively in the ipsilateral granule cell layer of lobules 9d and 10. Much sparser vestibular primary afferent projections were found in the banks of major cerebellar sulci. A barely detectable projection was found to the flocculus and ventral paraflocculus. © 19

ISSN:0092-7317    

DOI:10.1002/cne.903270405

出版商:Wiley‐Liss, Inc.    

年代:1993

数据来源: WILEY

摘要:

AbstractCannabinoid receptor mRNA was localized in adult rat brain by35S‐tailed oligonucleotide probes and in situ hybridization histochemistry. Labelling is described as uniform or non‐uniform depending on the relative intensities of individual cells expressing cannabinoid receptor mRNA within a given region or nucleus. Uniform labelling was found in the hypothalamus, thalamus, basal ganglia, cerebellum and brainstem. Non‐uniform labelling that resulted from the presence of cells displaying two easily distinguishable intensities of hybridization signals was observed in several regions and nuclei in the forebrain (cerebral cortex, hippocampus, amygdala, certain olfactory structures). Olfactory‐associated structures, basal ganglia, hippocampus, and cerebellar cortex displayed the heaviest amounts of labelling. Many regions that displayed cannabinoid receptor mRNA could reasonably be identified as sources for cannabinoid receptors on the basis of well documented hodologic data. Other sites that were also clearly labelled could not be assigned as logical sources of cannabinoid receptors. The localization of cannabinoid receptor mRNA indicates that sensory, motor, cognitive, limbic, and autonomic systems should all be influenced by the activation of this receptor by either exogenous cannabimimetics, including marijuana, or the yet unknown endogenous “cannabinoid” ligand. © 1993 Wil

ISSN:0092-7317    

DOI:10.1002/cne.903270406

出版商:Wiley‐Liss, Inc.    

年代:1993

数据来源: WILEY

摘要:

AbstractThe distribution ofproneuropeptide Y‐containing perikarya and nerve fibers in the brain ofRana esculenta and Xenopus laviswas determined with antisera directed toward neuropeptide Y and the carboxyl terminal flanking peptide.The distribution of proneuropeptide Y‐like immunoreactivity was similar in both anurans. In the telencephalon, immunoreactive perikarya were found in the olfactory bulb, all subdivisions of the pallium, the septum,pars lateralisof the amygdala, the nucleus accumbens, and the anterior preoptic area. In the diencephalon, labelled perikarya were detected in the ventromedial, ventrolateral and central thalamic nuclei, the magnocellular preoptic nucleus, the suprachiasmatic nucleus, the posterior tuberculum, and the infundibulum. Amacrine‐like cells were stained in the retina. In the pretectal area, posterior thalamic neurons showed intense, Golgi‐like immunostaining. In the mesencephalon, immunoreactive cells were found in the reticular nucleus, the anteroventral tegmental nucleus, the optic tectum, the interpeduncular nucleus, and the torus semicircularis. In the rhombencephalon, labelled perikarya were detected in the secondary visceral nucleus, the central gray, the nucleus of the solitary tract, the dorsal column nuclei, and the spinal nucleus of the trigeminal nerve.Immunoreactive nerve fibers were observed in all areas of the brain that contained labelled perikarya. The densest accumulations were found in the accessory olfactory bulb,pars lateralisof the amygdala, the ventral habenula, the posterior pituitary, the optic tectum, the interpeduncular nucleus, and the saccular nucleus.The distribution of proneuropeptide Y‐like immunoreactivity in the anuran brain showed many similarities to the distribution described for the amniote brain. © 1993 Wiley

ISSN:0092-7317    

DOI:10.1002/cne.903270407

出版商:Wiley‐Liss, Inc.    

年代:1993

数据来源: WILEY

摘要:

AbstractThe origin of cardiac vagal preganglionic motoneurones in the rat is still controversial and knowledge of the chemistry of synaptic inputs onto these neurones is limited. In this investigation vagal preganglionic motoneurones innervating the heart were identified by the retrograde transport of cholera toxin conjugated to horseradish peroxidase (CT‐HRP) combined with the immunocytochemical localization of 5‐hydroxytryptamine. Injection of CT‐HRP into the myocardium resulted in the retrograde labelling of neurones primarily in the ventral regions of the nucleus ambiguus (75.1%). Labelled neurones were also distributed in a narrow band through the reticular formation extending between the dorsal motor nucleus of the vagus nerve and the nucleus ambiguus (17.3%) as well as in the dorsal motor nucleus itself (7.6%).A combination of retrograde labelling with immunocytochemistry for 5‐hydroxytrypta‐mine revealed that the neuronal perikarya and the dendrites of cardiac vagal motoneurones in the nucleus ambiguus were often ensheathed in 5‐hydroxytryptamine‐immunoreactive axonal boutons. Electron microscopic examination of this material confirmed that there were synaptic specializations between these boutons and the cardiac vagal motoneurones. The identification of 5‐hydroxytryptamine‐containing synaptic inputs to this population of vagal motoneurones provides further detail towards the understanding of the regulation of heart rate by the parasympathetic nervous system. © 19

ISSN:0092-7317    

DOI:10.1002/cne.903270408

出版商:Wiley‐Liss, Inc.    

年代:1993

数据来源: WILEY

摘要:

AbstractThe serotoninergic innervation of the dorsal column nuclei (DCN) was investigated in cats and owl monkeys (Aotus trivirgatus) with immunohistochemical methods. A dense network of serotonin‐immunoreactive fibers was present in the reticular regions of DCN in cats, and in the pars triangularis of the cuneate nucleus and the peripheral and caudal regions of the gracile nucleus in owl monkeys. The cat's cluster regions and the monkey's rotund regions were more sparsely innervated. Electron microscopic examination showed that the labeled fibers were thin and unmyelinated. Vesicle‐containing, terminal‐like structures were small. They were in contact with dendrites, other terminals and cell bodies, but synapses were rare.The results demonstrate that the serotoninergic projection to the DCN in both cats and owl monkeys is heterogeneously distributed in a pattern that is faithfully related to the cytoarchitectonic subdivisions of the DCN. The densely innervated reticular regions in the DCN of cats and the corresponding regions in monkeys are predominantly involved in the processing of sensory information to the cerebellum, either directly, or indirectly through projections to the inferior olive, pontine gray, tectum, pretectum, red nucleus, or zona incerta. Thus, the present findings suggest that the serotoninergic innervation of the DCN is primarily related to the DCN's involvement in motor functions. © 1993 Wiley‐L

ISSN:0092-7317    

DOI:10.1002/cne.903270409

出版商:Wiley‐Liss, Inc.    

年代:1993

数据来源: WILEY

摘要:

AbstractThe distribution of noradrenergic processes within the hypothalamus of rhesus monkeys (Macaca mulatta) was examined by immunohistochemistry with an antibody against dopamine‐β‐hydroxylase. The results revealed that the pattern of dopamine‐β‐hydroxylase immunoreactivity varied systematically throughout the rhesus monkey hypothalamus. Extremely high densities of dopamine‐β‐hydroxylase‐immunoreactive processes were observed in the paraventricular and supraoptic nuclei, while relatively lower levels were found in the arcuate and dorsomedial nuclei and in the medial preoptic, perifornical, and suprachiasmatic areas. Moderate levels of dopamine‐β‐hydroxylase immunoreactivity were found throughout the lateral hypothalamic area and in the internal lamina of the median eminence. Very few immunoreactive processes were found in the ventromedial nucleus or in the mammillary complex. Other midline diencephalic structures were found to have high densities of dopamine‐β‐hydroxylase immunoreactivity, including the paraventricular nucleus of the thalamus and a discrete subregion of nucleus reuniens, the magnocellular subfascicular nucleus. A moderate density of dopamine‐β‐hydroxylase immunoreactive processes were found in the rhomboid nucleus and zona incerta whereas little dopamine‐β‐hydroxylase immunoreactivity was found in the fields of Forel, nucleus reuniens, or subthalamic nucleus. The differential distribution of dopamine‐β‐hydroxylase‐immunoreactive processes may reflect a potential role of norepineph‐rine as a regulator of a variety of functions associated with the nuclei that are most heavily innervated, e.g., neuroendocrine release from the paraventricular and supraoptic nuclei, and gonadotropin release from the medial preoptic area and mediobasal hypothalamus. Additionally, quantitative analysis of dopamine‐β‐hydroxylase‐immunoreactive varicosities was performed on a laser scanning microscope in both magnocellular and parvicellular regions of the paraventricular nucleus of the hypothalamus. The methodology employed in this study allowed for the high resolution of immunoreactive profiles through the volume of tissue being analyzed, and was more accurate than conventional light microscopy in terms of varicosity quantification. Quantitatively, a significant difference in the density of dopamine‐β‐hydroxylase‐immunoreactive varicosities was found between magnocellular and parvicellular regions, suggesting that parvicellular neurons received a denser noradrenergic input. These differential patterns may reflect an important functional role for norepinephrine in the regulation of anterior pituitary secretion through the hypotha

ISSN:0092-7317    

DOI:10.1002/cne.903270410

出版商:Wiley‐Liss, Inc.    

年代:1993

数据来源: WILEY

摘要:

AbstractDysfunction of cochlear mechanics has been hypothesized to be a source of age‐related hearing loss and the basilar membrane mass and stiffness contribute to normal cochlear mechanics. Fibronectin, a large, extracellular matrix protein and a major component of the basilar membrane, may contribute to both the mass and stiffness of the membrane. Mesothelial cells underlying the basilar membrane may produce the fibronectin and also contribute to the mass of the membrane. Changes in either the fibronectin or the mesothelial cells might, therefore, have an effect on cochlear mechanics. In order to assess basilar membrane changes in aged animals, young adult (2–4 months) and aged (24–26 months) Sprague‐Dawley rats were evaluated for the presence of fibronectin‐like protein and mesothelial cells. The basilar membrane in the young animals had strong fibronectin‐like immunoreactivity throughout its length. The old animals, on the other hand, showed normal fibronectin immunoreactivity in the basilar membrane of the basal turn, but little or no reactivity in the apical cochlear turn. The number of mesothelial cells was reduced throughout the length of the membrane in aged animals, with the greatest loss in the basal turn (60% fewer cells). These two degenerative changes, which appear to be independent of each other, may contribute to the observed threshold shifts in aged cochleas. © 1993 Wil

ISSN:0092-7317    

DOI:10.1002/cne.903270411

出版商:Wiley‐Liss, Inc.    

年代:1993

数据来源: WILEY