摘要:

AbstractA large body of experimental literature has demonstrated that neonatal infraorbital nerve damage in rodents produces anatomical and/or functional alterations of the normal whisker representation in central trigeminal structures. Less is known about the organization of primary afferent components of the trigeminal system following this manipulation. Such information provides an important basis for interpreting the central changes observed following damage of infraorbital nerve fibers at birth. We have therefore examined the composition and order of peripheral innervation in the pathway from the trigeminal ganglion to the vibrissa follicles in adult rats subjected to unilateral neonatal infraorbital nerve transectionElectron microscopy was used to determine the number and diameter of myelinated and unmyelinated fibers in vibrissa follicle nerves of these animals. Wheat germ agglutinin‐horseradish peroxidase and fluorescent retrograde tracers were employed to examine the number and diameter, as well as the topographic organization and branching, of ganglion cells innervating the vibrissae in these rats.The data presented below indicate that neonatal infraorbital nerve transection has the following consequences within the adult trigeminal nerve and ganglion: (1) an alteration of the gross morphology of vibrissal nerves, (2) a significant reduction in the average number (85.4%) and diameter (32.6%) of myelinated, but not unmyelinated, follicle nerve axons, (3) a significant decrease in the average number (36.8%) of trigeminal ganglion cells innervating vibrissa follicles, (4) no significant change in the distribution of ganglion cell diameters, (5) an increase in peripheral branching (1.8‐fold) of these ganglion cell axons, and (6) an alteration of somatotopic order within the trigeminal ganglion.Taken together, these data indicate that neonatal infraorbital nerve transection produces a profound reorganization of the primary afferent component of the trigeminal neura

ISSN:0092-7317    

DOI:10.1002/cne.902680402

出版商:Alan R. Liss, Inc.    

年代:1988

数据来源: WILEY

摘要:

AbstractRetrograde and anterograde transport of horseradish peroxidase‐wheat germ agglutinin (HRP‐WGA) conjugate was used to study the organization of primary afferent neurons innervating the masticatory muscles. HRP applied to the nerves of jaw‐closing muscles–the deep temporal (DT), masseter (Ma), and medial pterygoid (MP)–labeled cells in the trigeminal ganglion and the mesencephalic trigeminal nucleus (Vmes), whereas HRP applied to nerves of the jaw‐opening muscles–anterior digastric (AD) and mylohyoid (My)–labeled cells only in the trigeminal ganglion. Cell bodies innervating the jaw‐closing muscles were found with greater frequency in the intermediate region of the mandibular subdivision, while somata supplying the jaw‐opening muscles were predominant posterolaterally. The distribution of their somatic sizes was unimodal and limited to a subpopulation of smaller cells. Projections of the muscle afferents of ganglionic origin to the trigeminal sensory nuclear complex (TSNC) were confined primarily to the caudal half of pars interpolaris (Vi), and the medullary and upper cervical dorsal horns. In the Vi, Ma, MP, AD, and My nerves terminated in the lateral‐most part of the nucleus with an extensive overlap in projections, save for the DT nerve, which projected to the interstitial nucleus or paratrigeminal nucleus. In the medullary and upper cervical dorsal horns, the main terminal fields of individual branches were confined to laminae I/V, but the density of the terminals in lamina V was very sparse. The rostrocaudal extent of the terminal field in lamina I differed among the muscle afferents of origin, whereas in the mediolateral or dorsoventral axis, a remarkable overlap in projections was noted between or among muscle afferents. The terminals of DT afferents were most broadly extended from the rostral level of the pars caudalis to the C3 segment, whereas the MP nerve showed limited projection to the middle one‐third of the pars caudalis. Terminal fields of the Ma, AD, and My nerves appeared in the caudal two‐thirds of the pars caudalis including the first two cervical segments, the caudal half of the pars caudalis and the C1 segment, and in the caudal part of the pars caudalis including the rostral C1 segment, respectively. This rostrocaudal arrangement in the projections of muscle nerves, which corresponds to the anteroposterior length of the muscles and their positions, indicates that representation of the masticatory muscles in lamina I reflects an onion‐skin organization. These results suggest that primary muscle afferent neurons of ganglionic origin primarily mediate muscle pain. In addition, the distribution patterns of the afferent neurons of jaw‐closing muscles in the mesencephalic trigeminal nucleus (Vmes) and their central projections were examined. The Vmes neurons from the DT and Ma nerves were bimo‐dally distributed, with larger numbers in the rostra1 half of the nucleus, whereas those from the MP nerve were sparsely and evenly distributed. Individual central axons of the Vmes neurons innervating the three jaw‐closing muscles projected to the trigeminal motor nucleus (Vmo), supra‐ and intertrigeminal regions, and lateral reticular formation of the medulla extending to the upper spinal cord. There were, however, differences in the caudal extent of t

ISSN:0092-7317    

DOI:10.1002/cne.902680403

出版商:Alan R. Liss, Inc.    

年代:1988

数据来源: WILEY

摘要:

AbstractCerebellar projections to oculomotor‐related brainstem regions were studied in four groups of New World (capuchin, squirrel) monkeys by using the retrograde transport of horseradish peroxidase (HRP) to determine the origin of the principal cerebellar influence on eye movement.Group A monkeys had HRP injections or transcannular HRP gel implants into the oculomotor complex (OMC), the largest of which involved adjacent paraoculomotor nuclei (e.g., ventral periaqueductal gray, PAG; nucleus of Darkschewitsch, ND; medial accessory nucleus of Bechterew, MAB; dorsomedial parvicellular red nucleus, dmPRN). All of these cases contained large numbers of retrogradely labeled cells in cell group Y. Whereas the smallest OMC injection only labeled a few cells in the dentate nucleus (DN), injections involving paraoculomotor nuclei produced labeling in all of the cerebellar nuclei except the basal interstitial nucleus (BIN). Injections extending into the ND and MAB produced particularly heavy labeling within the interposed nuclei.Group B monkeys had injections/implants into the medial pontine tegmentum and dorsomedial basilar pons. The pontine tegmental cases contained labeled cells in all cerebellar nuclei, but the DN was the most heavily labeled when the implant involved the nucleus reticularis tegmenti pontis (NRTP). Cases with injections into the caudal medial pontine tegmentum (nucleus reticularis pontis caudalis, NRPC), including the physiological paramedian pontine reticular formation (PPRF), but not NRTP, contained the largest number of labeled cells in the fastigial nucleus (FN) and lacked retrograde labeling in the DN. Dorsomedial basilar pontine cases contained almost no labeled cells in the FN, anterior interpositus nucleus (AIN), and posterior interpositus nucleus (PIN) but did contain DN labeling when the injection involved the NRTP. Two dorsomedial pontine tegmental cases and one dorsomedial basilar pontine case had more labeled cells in the BIN than in other cases. Tegmental cases also contained a few labeled cells in cell group Y.Group C monkeys had injections into the parvicellular red nucleus (PRN) and had their heaviest labeling in the DN, although the AIN and PIN also contained labeled cells. The FN, BIN, and cell group Y, on the other hand, contained almost no labeling.Group D consisted of monkeys which had injections into the intermediate and deep superior colliculus (SC). These cases contained thelargest numbers of labeled cells in the PIN and a lesser number in the ventrolateral FN. The DN, AIN, BIN, and cell group Y lacked labeled neurons in these cases.The retrograde labeling in the FN raised important issues with regard to oculomotor function. The FN projected to the supraoculomotor part of the ventral PAG, known to contain preoculomotor neurons, to the caudal medial pontine reticular formation (including PPRF), and toa lesser degree to the deep SC. Considering its other well‐established projections to the perihypo‐glossal complex and vestibular nuclei, the FN probably has a more significant influence on the oculomotorsystem than other deep cerebellar nuclei. The possible convergence of frontal eye field and cerebellar projections in paraoculomotor nuclei, PPRF, NRTP, SC, and perihypoglossal complex is also disc

ISSN:0092-7317    

DOI:10.1002/cne.902680404

出版商:Alan R. Liss, Inc.    

年代:1988

数据来源: WILEY

摘要:

AbstractTwo different descending projections from the pontine gigantocellular tegmental field (PFTG) were denned by the use of intracellular recording and intracellular horseradish peroxidase (HRP) techniques in the cat. Type I neurons (reticulospinal neurons) had antidromic spike potentials produced by stimulation of the ipsilateral medial longitudinal fasciculus (MLF) and sent axons to the ipsilateral MLF. Most type I neurons had large ellipsoidpolygonal somata (mean, 59.7 μm), thick axons (average diameter, 3.33 μm), and slightly oblate large dendritic fields. The mean anteroposterior extent of the dendritic field was 1,492 μm, the mean mediolateral extent was 1,784 μm, and the mean dorsoventral extent was 1,562 μm. There were no type I neurons with axon collaterals. In contrast, type II neurons (reticuloreticular neurons) had antidromic spike potentials produced by stimulation of the bulbar reticular formation (BRF) and sent axons directly to the BRF. In comparison with type I neurons, most type II neurons had smaller ellipsoid‐polygonal somata (mean, 40.2 μm), thinner axons (average diameter, 2.32 μm), and smaller, slightly oblate dendritic fields. The mean anteroposterior extent of the dendritic field was 1,264 μm; the mean mediolateral extent was 1,511 μm; and the mean dorsoventral extent was 1,226 μm. Also in contrast to type I neurons, 36% of type II neurons had axon

ISSN:0092-7317    

DOI:10.1002/cne.902680405

出版商:Alan R. Liss, Inc.    

年代:1988

数据来源: WILEY

摘要:

AbstractThe trajectories and the cells of origin of the pontobulbar gigantocellular tegmental field descending pathways were studied in the cat using anterograde WGA‐HRP and retrograde HRP techniques. Four main descending pathways and cells of origin were delineated: (1) Predominantly large neurons in the pontine gigantocellular tegmental field (average soma diameter = 43.4 μm) and rostral bulbar gigantocellular tegmental field (41.3 μm) gave rise to reticulospinal fibers descending in the ipsilateral medial longitudinal fasciculus and ventral funiculus and distributed in laminae V‐X with an ipsilateral predominance. These were primarily large‐diameter fibers. (2) Predominantly large neurons (46.9 μm) in the bulbar gigantocellular tegmental field gave rise to reticulospinal fibers descending in the contralateral medial longitudinal fasciculus and ventral funiculus. These were mainly large‐diameter fibers. (3) Neurons of predominantly medium size (29.5 μm) in the pontine gigantocellular tegmental field gave rise to reticuloreticular fibers descending directly to and distributed bilaterally in the bulbar reticular formation. These were small‐diameter fibers. (4) Neurons of predominantly medium size (28.9 μm) in the bulbar gigantocellular tegmental field gave rise to reticulospinal fibers descending in the ipsilateral reticular formation and lateral funiculus. These were small

ISSN:0092-7317    

DOI:10.1002/cne.902680406

出版商:Alan R. Liss, Inc.    

年代:1988

数据来源: WILEY

摘要:

AbstractThe neuronal connections of the cerebellar corpus in the guitarfishPlatyrhinoidis triseriatawere investigated by WGA‐HRP injections and extracellular recording of sensory evoked electrical activity. Injections of WGA‐HRP into the corpus resulted in retrograde labeling of the following cell groups bilaterally: pretectal and accessory optic nuclei, interstitial nucleus of Cajal, nucleus ruber, oculomotor and possibly trochlear nucleus, central (periaqueductal) gray, nucleus H, reticular formation of the midbrain, cerebellar nucleus, caudal part of nucleus R tentatively locus coeruleus and subcoeruleus field, octaval and trigeminal nuclei, intermediate octavolateralis nucleus, medial inferior reticular formation, lateral reticular nucleus, and spinal cord. Unilaterally labeled cells were seen in the contralateral inferior olive, which was found to project in. sagittal zones onto the molecular layer of the corpus. Terminal fields of efferent Purkinje cell axons were labeled over the ipsilateral cerebellar nucleus exclusively. Purkinje cells in different parts of the corpus project topographically onto subdivisions of the nucleus.Mapping of evoked electrical multiple unit activity recorded from the granule cell layer of the corpus shows separate visual and tactile areas, mostly confined to the anterior and posterior lobes, respectively. Granule cells within the tactile area also responded to lateral line stimuli and, at two distinct medial locations in the caudal and rostral parts of the posterior lobe, to weak electric field stimulation in the bath. The body surface is somatotopically represented in the tactile area, but discontinuities in the map might indicate that the somatotopy is “fract

ISSN:0092-7317    

DOI:10.1002/cne.902680407

出版商:Alan R. Liss, Inc.    

年代:1988

数据来源: WILEY

摘要:

AbstractAntibodies to the catecholamine synthetic enzymes tyrosine hydroxylase (TH), dopamine‐β‐hydroxylase (DBH), and phenylethanolamine‐N‐methyltransferase (PNMT) were used in an immunohistochemical analysis of the brain of the golden hamster. The distributions and morphological characteristics of neurons displaying immunoreactivity to these enzymes were examined in sets of adjacent sections. Various novel groups of TH‐immunoreactive neurons were found. A distinct feature observed in the hamster brain was the presence of a population of magnocellular multipolar neurons in the basal forebrain which displayed intense TH immunoreactivity. These cells were found predominantly in the vertical and horizontal limbs of the nucleus of the diagonal band of Broca and in the lateral preoptic area. Many small TH‐positive cells were also found scattered in the deeper layers of the cortex in the hamster. The pericentral divisions of the inferior colliculus contained a large number of TH‐immunoreactive neurons, and a few small bipolar cells in the lateral superior olive were also stained; A major cell group was found in the lateral parabrachial nucleus at the level of the locus ceruleus that displayed TH but not DBH immunoreactivity and was obviously separate from the TH‐ and DBH‐positive cells of the locus ceruleus. Additional TH‐positive cell groups were found along the seventh nerve, within the medial longitudinal fasiculus, in the nucleus raphe pallidus, and in the pars caudalis of the spinal trigeminal nucleus.The various catecholamine cell groups described by many people in the rat by use of histochemical and immunohistochemical techniques were also present in the hamster brain. These included the noradrenergic, TH‐ and DBH‐immunoreactive cell groups of the pons and medulla. The hamster also displayed groups of medullary neurons displaying immunoreactivity to TH, DBH, and PNMT. These appeared similar in distribution and morphology to the adrenaline cell groups described in the rat. TH‐immunoreactive cell groups in the olfactory bulb, hypothalamus, substantia nigra, and ventral tegmental area of the hamster appeared to correspond to the dopaminergic cells groups described in the rat and other species. In addition, as in the rat and cat, numerous TH‐positive cells were found in the dorsal motor nucleus of the vagus, the nucleus of the solitary tract, and the area postrema.These observations suggest that catechols may be present in neurons in the cortex, basal forebrain, auditory brainstem, and the parabrachial nucleus of the hamster. These studies also emphasize the need for caution in making‐ generalizations regarding transmitte

ISSN:0092-7317    

DOI:10.1002/cne.902680408

出版商:Alan R. Liss, Inc.    

年代:1988

数据来源: WILEY

摘要:

AbstractThe distribution and development of vasoactive intestinal polypeptide (VIP) immunoreactive elements were studied in the spinal cord of embryonic and newly hatched chicks with the indirect immunofluorescence method. VIP neurons were first detectable in the presumed dorsal horn at stages 27–28 (incubation day 5). Subsequently they increased in number, and by stage 39 (day 12) many occurred in lamina I, in the nucleus of the dorsolateral funiculus, and in the lateral portion of the neck of the dorsal horn throughout the cord. However, at the thoracic level many were also situated lateral to the central canal, with their processes running to the ipsilateral lateral and contralateral ventral funiculi. The pattern described above remained visible in both embryonic and colchicine‐pretreated newly hatched chicks.During development, VIP fibers appeared later than cell bodies. In the gray matter, they were mainly scattered in the intermediate zone, especially around the central canal at all levels examined. In the white matter, however, longitudinal fibers were observed in the lateral funiculus throughout the cord, but mostly at the cervical level, though some also occurred in the ventral funiculus. This finding supports the idea that spinal VIP neurons might project rostrally via the lateral funiculus.In addition, no VIP immunoreactivity was found in the spinal ganglia, but examination of the sympathetic paravertebral ganglia showed immunoreactivity as described by oth

ISSN:0092-7317    

DOI:10.1002/cne.902680409

出版商:Alan R. Liss, Inc.    

年代:1988

数据来源: WILEY

ISSN:0092-7317    

DOI:10.1002/cne.902680401

出版商:Alan R. Liss, Inc.    

年代:1988

数据来源: WILEY