摘要:

AbstractSomatostain‐immunoreactive neurons in the rat neostriatum were studied by correlated light and electron microscopy using the peroxidase‐antipe‐roxidase immunocytochemical technique. Immunoreactivity was localized in neuronal perikarya and processes. The perikarya were of spindle or fu‐siform shape (average length 16.9 μm) and were found in all parts of the neostriatum. From each neuron there arose two to four straight immuno‐reactive dendritelike processes, which could frequently be traced as far as about 130 μm from their perikaryon. Immunoreactive varicose axonlike processes were occasionally found, some of which were proximal axons of identified immunoreactive cells. Nine of the light microscopically identified neurons showing somatostatin‐immunoreactivity were studied in the elec‐tron microscope; two of them had proximal axons with varicosities. Each neuron had an oval or elongated nucleus, which was always indented. These morphological features correspond well to those of certain “medium‐size aspiny” neurons classified by Golgi studies. Although the immunoreactive endproduct was diffusely located throughout the neuron, it was character‐istically located in the saccules and large granules (diameter 133 nm) of the Golgi apparatus, and large immunoreactive vesicles of similar size to those in the Golgi apparatus frequently occurred in all parts of axon. Very little synaptic input was found on the perikarya and dendrites of somato‐statin‐immunoreactive neurons. The perikarya and proximal dendrites re‐ceived both symmetrical and asymmetrical synaptic input, while the distal dendrites usually received boutons that formed asymmetrical contacts.The somatostatin‐immunoreactive boutons contained pleomorphic elec‐tron‐lucent vesicles (diameter 39.3 nm) and a few large immunoreactive granular vesicles; these boutons always formed symmetrical synapses. Their postsynaptic targets were dendritic shafts, spines, and unclassified dendritic profiles. On the other hand, the varicosities of identified proximal axons of somatostatin‐positive neurons did not form typical synapses, since they lacked clusters of small vesicles, but some of them were in direct apposition (via membrane specializations) to unlabelled perikarya or dendrites.It is concluded that somatostatin is a useful marker for a particular type of neuron in the neostriatum. The presence of somatostatin immunp‐reactivity in synaptic boutons is consistent with the view that somatostatin could b

ISSN:0092-7317    

DOI:10.1002/cne.902140102

出版商:Alan R. Liss, Inc.    

年代:1983

数据来源: WILEY

摘要:

AbstractCorticothalamic projections from postcruciate area 4, located on the rostral part of the posterior sigmoid gyms, were traced with the autora‐diographic technique in the dog. Injections of tritiated amino acids were made into the lateral and medial parts of area 4 in regions corresponding to the forelimb and hindlimb areas of the primary motor cortex, respectively. In cases with injections placed in the lateral part of areas, dense accu‐mulations of label were present in the lateral part of the ventral anterior nucleus (VA), the central part of the ventral lateral nucleus (VL), the ventral half of the ventral posterior inferior nucleus (VPI), the caudal part of the central lateral nucleus (CL), and the centrum medianum (CM). Lighter label was also present in the lateral part of the cytoarchitectonically distinct VL region bordering the ventrobasal complex (VB), as well as in the ventro‐lateral part of the mediodorsal nucleus (MD), and in the lateral posterior nucleus (LP). In one case in which the injection site involved an adjacent part of area 3a, label was also seen ventrally in the medial division of the posterior nuclear group (POm). However, no detectable differences in VL, MD, or intralaminar labeling patterns were noted between this case and the four other cases with injections confined to the lateral part of area 4. In two cases with injections restricted to the medial part of area 4, dense label was present in the lateralmost part of VL, the ventral part of VPI, the caudal part of CL, and CM. Lighter label was also present in the VL region bordering the dorsolateral edge of VB and in LP. An additional case in which the injection also involved the rostral border of area 3a showed a similar pattern cf thalamic labeling. Projections from both the lateral and medial parts of area 4 were also noted in the subthalamic nucleus, zona incerta, and nucleus of Darkschewitsch.These results suggest that Corticothalamic projections from postcruciate area 4 to VL are organized topographically such that projections from the lateral part of area 4 project centrally within VL while those from the medial part of area 4 project more laterally. Both parts of area 4 also project top‐ographically to a cytoarchitectonically distinct region of VL located im‐mediately adjacent to VB, In contrast, the projections to the intralaminar nuclei do not appear to be topographically organized. The data from cases involving spread of the injection into area 3a suggest that projection pat‐terns from area 3a to ventral, intralaminar, and medial thalamic nuclei are similar to those from area 4. However, it appears that at least the lateral part of area 3a also proj

ISSN:0092-7317    

DOI:10.1002/cne.902140103

出版商:Alan R. Liss, Inc.    

年代:1983

数据来源: WILEY

摘要:

AbstractThe axonal endings on the somata and dendrites of third‐order auditory neurons in nucleus laminaris (NL) were measured and classified in thin‐sectioned material from adult chickens. Two methods were used to deter‐mine which ending types arise from second‐order auditory neurons in nu‐cleus magnocellularis (NM): (1) degeneration of axonal endings in NL after transection of the crossed dorsal cochlear tract (CTrX) carrying the axons of each NM to the contralateral NL, and (2) injection of horseradish per‐oxidase (HRP) into NM or the CTrX to label endings in NL by anterograde transport. About 42% of the perikaryl surface of NL neurons and 63% of the dendritic surface are apposed by axon terminals arising from NM; these endings are also prevalent on the axon hillock and initial segment. The NM endings are characterized by round, clear synaptic vesicles‐distributed at an average density of 76/μm2 behind small punctate synaptic junctions with thick synaptic densities. These endings degenerate preferentially after tran‐section of the CTrX and are the only endings consistently labeled after HRP injections. About 31% of the perikaryl surface of NL and 10% of the distal dendritic surface are apposed by a prominent non‐NM axonal ending type This ending is characterized by a synaptic vesicle density of 135/ μm2 a single large area of synaptic contact which bears very slight densities on both pre‐ and postsynaptic membranes. On the perikaryon, about 80% of these non‐NM terminals end on the cell body proper, with the rest found on proximal dendrites or capping the short somatic processes or spines occasionally seen in NL. The distribution of the two ending types does not differ significantly along the posterior

ISSN:0092-7317    

DOI:10.1002/cne.902140104

出版商:Alan R. Liss, Inc.    

年代:1983

数据来源: WILEY

摘要:

AbstractAfferents of the nucleus raphe magnus (NRM) were retrogradely la‐belled by using a transcannula HRP gel technique in conjunction with tetramethylbenzidine nuerohistochemistry to determine the sources of in‐puts to the nucleus which could potentially influence the descending antio‐ciceptive raphe‐spinal system. Large numbers of HRP‐labelled neurons were seen in the frontal cortex, dorsomedial nucleus of the hypothalamus, zona incerta, nucleus parafascicularis prerubralis (NPfPr), pretectum, dorsal and lateral periaqueductal gray, nucleus cuneiformis (NC), deep superior col‐liculus (dSC), a paraoculomotor cell group which may be the medial acces‐sory nucleus of Bechterew, dorsal column nuclei, and spinal trigeminal nucleus. Smaller numbers of labelled cells were also observed in the preoptic area, nucleus of Darkschewitsch, ventral peri(third)ventricular gray, nu‐cleus reticularis pontis oralis and caudalis, medial and lateral vestibular nuclei, and a subdivision of the hypoglossal nucleus. Confirmational an‐terograde autoradiographic studies were performed by injecting tritiated leucine into two of the principal sources of afferents to NRM: NPfPr, and dSC/NC.The results are compared with control HRP gel implants in the inferior olive, spinal cord, nucleus reticularis paragigantocellularis, and medial fa‐cial nucleus. Comments are also made concerning the parcellation of the ventromedial medulla and the possible role of both NRM and its afferents in central a

ISSN:0092-7317    

DOI:10.1002/cne.902140105

出版商:Alan R. Liss, Inc.    

年代:1983

数据来源: WILEY

摘要:

AbstractWe studied the receptive field properties of 206 single units in area 19 of normal cats and 228 single units in area 19 of cats deprived of vision for 9‐14 months by monocular lid suture. The ocular dominance of a sample of cells in area 17 of normal cats was studied for comparison. In some of these monocularly deprived animals, we also studied the sizes of relay cells in the parvocellular C laminae of the dorsal lateral geniculate nucleus labeled by electrophoretic injections of horseradish peroxidase into area 19.In area 19 of normal cats, the large majority of cells, regardless of their laminar location and the retinal eccentricity of their receptive fields, were binocular. Most responded equally well to the two eyes. In area 17, (see also Leventhal and Hirsch, ′78, ′80) but not in area 19, the cells which had the narrowest receptive fields tended to be activated unequally by the two eyes.In area 19 of monocularly deprived cats, virtually all cells (97%), re‐gardless of their laminar location and receptive field eccentricity, responded only to stimulation of the normal eye. Thus, the effects of monocular dep‐rivation upon area 19 are apparently more severe than those reported for area 17. In area 17 significant numbers of neurons in layer 4 can be activated by the deprived eye (Shatz and Stryker, ′78). Within the limits of our tech‐nique, measurements of relay cells in the parvocellular C laminae labeled by injections into area 19 of deprived cats indicated that cell size in the deprived C laminae was unaffected by the deprivation. In contrast, cells in the deprived A laminae of these cats were severely shrunken.These findings suggest that the types of relay found in the parvocellular C laminae (referred to collectively as W‐cells) are not affected by visual deprivation as severely as are the X‐ and Y‐cells in the A laminae. Since laminar location and receptive field width are related to binocularity in area 17 but not in area 19 and the sizes of relay cells in the parvocellular C laminae (see also Hickey, ′80) are not seriously affected by monocular deprivation, it is suggested that binocular interactions in area 19aremninly determined by connections

ISSN:0092-7317    

DOI:10.1002/cne.902140106

出版商:Alan R. Liss, Inc.    

年代:1983

数据来源: WILEY

摘要:

AbstractThe present study determines the numbers of myelinated and unmye‐linated axons in the ventral and lateral funiculi of rat sacral spinal cord. On average, there are 55,000 myelinated and 110,000 unmyelinated axons in the lateral funiculus and 26,000 myelinated and 9,000 unmyelinated axons in the ventral funiculus at these levels. These figures combined with data from earlier studies of the posterior funiculus and the tract of Lissauer give approximate figures of 88,500 myelinated and 131,500 unmyelinated axons for the entire white matter of one side of the rat sacral spinal cord. Thus unmyelinated axons predominate in the white matter of the rat sacral spinal cord.The majority of axons, particularly the unmyelinated axons, are located in the lateral funiculus. The axons are concentrated in the dorsalateral part of the lateral funiculus, and so the dorsal part of the lateral funiculus, of ten referred to as the dorsolateral funiculus, contains more than half the fibers in the white matter of the spinal cord. A small nick in the dorsal and lateral part of the lateral funiculus, which is often done for various experimental reasons, could thus remove 40% of the axons in the white matter of rat sacral spinal cord.The data reported in the present paper will serve as a basis for future studies on the white matter of the isolated spinal cor

ISSN:0092-7317    

DOI:10.1002/cne.902140107

出版商:Alan R. Liss, Inc.    

年代:1983

数据来源: WILEY

摘要:

AbstractThis investigation describes the origin of the rubrospinal tract in neo‐natal (1‐10 days old), developing (15‐20 days old), and mature (2‐4 months old) rats studied by using the horseradish peroxidase (HRP) method of tracing neuronal connections. HRP was administered in the cervical or lumbosacral segments of the spinal cord either in the crystal or solution form. The results showed that the rubrospinal tract extended to the lum‐bosacral part of the spinal cord at birth. There appeared to be no difference in the pattern of labelled rubrospinal (RS) neurons following the admin‐istration of HRP in the cervical or the lumbosacral cord segment of the neonatal, developing, and mature rats. In rats of these three age groups, labelled neurons were found bilaterally in the red nucleus, with a contra‐lateral predominance, and they were found in both the parvicellular and magnocellular portions of the red nucleus. There was a somatotopic ar‐rangement in the labelled RS neurons: Those projecting to the cervical cord segments were located in the dorsal and dorsomedial regions of the red nucleus and those projecting to the lumbosacral cord segments were located in the ventral and ventrolateral regions

ISSN:0092-7317    

DOI:10.1002/cne.902140108

出版商:Alan R. Liss, Inc.    

年代:1983

数据来源: WILEY

摘要:

AbstractVarious enzymes are released from the nigro‐striatal pathway. The hypothesis that these enzymes–i.e., acetylcholinesterase, nonspecific cho‐linesterase, aminopeptidase, and lactate dehydrogenase–originate from do‐paminergic nigro‐striatal neurons was investigated. Following a 6‐hydrox‐ydopamine lesion of the rat nigro‐striatal pathway, the spontaneous release of all four enzymes was reduced, in both the caudate nucleus and substantia nigra. In both structures the reduction in release of aminopeptidase and lactate dehydrogenase was less marked than that seen for acetylcholines‐terase and nonspecific cholinesterase. In nonlesioned rats, application of 50 mM KC1 to the substantia nigra led to an increase in enzyme release locally, accompanied by a decrease in release from the caudate nucleus. These changes were observed in release of acetylcholinesterase, aminopeptidase, and lac‐tate dehydrogenase, but nonspecific cholinesterase remained unchanged. In rats with 6‐hydroxydopamine lesions, nigral application of potassium no longer induced a significant decrease in release from the caudate nucleus in any of the enzymes. In perfusates of the treated group, however, a po‐tassium‐evoked increase in nigral aminopeptidase and lactate dehydrogen‐ase release was still detectable. Nigral acetylcholinesterase release was not affected by potassium in animals with 6‐hydroxydopamine lesions. It ap‐pears that lactate dehydrogenase and aminopeptidase are released together from both dopamine‐ and non‐dopamine‐containing cells in the caudate nucleus and substantia nigra; this release may be related to neuronal de‐polarization. A high proportion of nonspecific cholinesterase is released from nigro‐striatal dopamine‐containing cells but appears not to be dependent on depolarization. Acetylcholinesterase, which is released in the caudate nucleus and substantia nigra following neuronal depolarization, originates almost exclusively fr

ISSN:0092-7317    

DOI:10.1002/cne.902140109

出版商:Alan R. Liss, Inc.    

年代:1983

数据来源: WILEY

摘要:

AbstractTo identify the midbrain nuclei that project to the medial part of the lower brainstem in the monkey, labeled cells were mapped in the midbrain following the injection of horseradish peroxidase into the medial medulla oblongata. After the general distribution of labeled cells was observed in three animals with large injections, more discrete injections of HRP were made in different locations in six additional animals. The small injections were centered in the nucleus raphe magnus, nucleus reticularis giganto‐cellularis, or nucleus medullae oblongatae centralis. The five labeled mid‐brain nuclei were the periaqueductal gray, nucleus cuneiformis, deep layers of the superior colliculus, nucleus of Darkschewitsch, and the interstitial nucleus of Cajal. In addition, the parvocellular division of the red nucleus and the posterior pretectal nucleus contained large numbers of cells when the injection spread into the inferior olive. No major differences in the distribution of labeled cells between different injection sites were found with the exception that the superior colliculus did not contain any labeled cells when the injection was restricted to midline structures. The functional implications of these anatomical findings are discussed in relation to the descending control of p

ISSN:0092-7317    

DOI:10.1002/cne.902140110

出版商:Alan R. Liss, Inc.    

年代:1983

数据来源: WILEY

摘要:

AbstractThe afferent connections to the Wulst, a well‐defined bulge in the fore‐brain roof, were studied in the pigeon. Cells of origin were identified by horseradish peroxidase retrograde tracing, after placing multiple injections in the Wulst.The results demonstrate a bilateral intratelencephalic pathway arising from the archistriatum intermedium (Ai) in the basal forebrain. Labeled cells in n. superficialparvocellularis (SPC) and n. dorsolateralis posterior (DLP) on both sides of the brain, provide anatomical evidence for a bilateral forebrain projection of the somatosensory thalamus. A sparse ipsilateral input of unknown function from the medial thalamus originates in n. dor‐somedialisanterior(DMA)and n. dorsolateralis medialis (DLM).Weprovide confirminge vidence of the bilateral thalamofugal visual pathway ascending from nuclei of the dorsolateral thalamus (DLAmc and DLL). Projections from several brain stem structures are described, including: griseum cen‐trale (GCt), medial and lateral reticular formation (FRM and FRL), area ventralis of Tsai (AVT), n. annularis (Anl), locus coeruleus (LoC), and the avian homologue of the raphe nucleus, n. linearis caudalis (LC).The account provides a direct anatomical demonstration of a Wulst input from the basal forebrain, the somatosensory thalamus, and the brain‐stem. The projection cells in the brainstem reside in structures known to contribute to ascending catecholaminergic and serotoninergic

ISSN:0092-7317    

DOI:10.1002/cne.902140111

出版商:Alan R. Liss, Inc.    

年代:1983

数据来源: WILEY