摘要:

AbstractThe projections of the locus coeruleus and adjacent pontine tegmentum have been studied using anatomical and physiological methods in the cat. Axonal trajectories were traced using either the Fink‐Heimer I method following electrolytic lesions, or the autoradiographic method after injection of tritiated proline into the nucleus. Results with both methods were similar. Axons of locus coeruleus neurons ascended ipsilaterally through the mesencephalon lateral to the medial longitudinal fasciculus, ventrolateral to the central gray. In the caudal diencephalon, the ascending fibers entered the centrum medianum‐parafascicular complex where they diverged into two fascicles; a dorsal fascicle which terminated in the intralaminar nuclei of the thalamus, and a ventral fascicle which gave off fibers to the ventrobasal complex and reticular nucleus of the thalamus while continuing ventrolaterally into the lateral hypothalamus medial to the internal capsule. Fibers of the ventral fascicle ascended in the lateral hypothalamus and zona incerta and were traced through the preoptic region into the septum. Fibers could not be consistently traced to the cerebral cortex, and were not seen at all in the cerebellum.Throughout the ascending course of the path from the locus coeruleus, axons were given off to the pretectal area, the medial and lateral geniculate nuclei, and the amygdala; fibers passed contralaterally through the posterior commissure, the midline thalamus, and the supraoptic commissure. Fibers descending from the locus coeruleus surrounded the intramedullary portion of the facial nerve and further caudally were observed ventrolateral to the hypoglossal and dorsal vagal nuclei.The axonal trajectories visualized with degeneration and autoradiographic methods followed closely those previously shown for reticular formation neurons, but were also similar to locus coeruleus projections revealed by histofluorescence methods. After injections of horseradish peroxidase into the centrum medianum‐parafascicular complex, lateral hypothalamus or preoptic region, labeled neurons were located in the locus coeruleus, nucleus subcoeruleus, and lateral parabrachial nucleus. Reticular formation neurons were not labeled. Neurons in locus coeruleus and adjacent pontine tegmentum could be antidromically activated by stimulation in the rostral midbrain or caudal diencephalon.Our data indicate that both adrenergic and non‐adrenergic neurons of the dorsolateral pontine tegmentum have similar proj

ISSN:0092-7317    

DOI:10.1002/cne.901650302

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

年代:1976

数据来源: WILEY

摘要:

AbstractThe ventricular sulcal pattern and the cellular structure of the brain stem of the axolotlAmbystoma mexicanumhave been studied in transversely cut Nissl and Bodian stained serial sections. Six longitudinal sulci, the sulcus medianus inferior, the sulcus intermedius ventralis, the sulcus limitans, the sulcus intermedius dorsalis, the sulcus medianus superior and the sulcus lateralis mesencephali could be distinguished. A seventh groove, the sulcus isthmi, clearly deviates from the overall longitudinal pattern of the other sulci. Although most neuronal perikarya are contained within a diffuse periventricular gray, 19 cell masses could be delineated: seven of these are primary efferent or motor nuclei, four are primary afferent or sensory centers, four nuclei are considered as components of the reticular formation, and the remaining four cell masses can be interpreted as “relay” nuclei.In order to study the zonal pattern of the brain stem, this structure was subjected to a topological analysis )cf. Nieuwenhuys, '74 and fig. 13(. This analysis yielded the following results. In the rhombencephalon the grisea are arranged in four longitudinal zones which, following Kuhlenbeck, have been termed: area ventralis, area Intermedioventralis, area intermediodorsalis and area dorsalis. Where present the sulcus intermedius ventralis, the sulcus limitans and the sulcus intermedius dorsalis mark the boundaries between these four morphological entities. The zonal areas in question coincide largely, but not sntirely, with the so‐called functional columns of Herrick and Johnston. The most obvious incongruity is that the area intermediodorsalis contains, in addition to the nucleus fasciculi solitarii and the nucleus visceralis secundarius, two non‐visceral sensory cell masses, namely the nucleus vestibularis magnocellularis and the nucleus cerebelli. The four morphological zones delineated in the rhombencephalon cannot be distinguished in the mesencephalon and it is of particular importance that the sulcus limitans does not extend into this part of the brain. Functionally, however, the medial part of the tegmentum mesencephali may be considered the rostral extreme of the somatic motor column, whereas the tectum primarily represents a somatic sensory correlati

ISSN:0092-7317    

DOI:10.1002/cne.901650303

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

年代:1976

数据来源: WILEY

摘要:

AbstractThe ventricular sulcal pattern and the cytoarchitectonic organization of the brain stem of the frogsRana esculentaandRana catesbeianahave been studied in transversely cut, Nissl stained serial sections. Four longitudinal sulci, the sulcus medianus inferior, the sulcus intermedius ventralis, the sulcus limitans and the sulcus medianus superior could be distinguished in both species. A fifth longitudinal groove, the sulcus intermedius dorsalis, was found only inRana esculenta. With the aid of the usual cytoarchitectonic criteria 25 cell masses have been delineated inRana esculentaand 27 inRana catesbeiana. These cell masses can be distributed over the following categories )numbers added in brackets forRana catesbeiana, if different from those inRana esculenta(: primary efferent or motor, 8: primary afferent or sensory, 4 )6(; “relay” centers, 7. Contrary to statements in the literature the reticular formation can be divided into six separate cell groups. The majority of the nuclei form part of the central gray, which constitutes a rather wide zone in anurans; three reticular nuclei lie partly within the stratum griseum and partly within the stratum album; six nuclei are entirely embedded in the stratum album.The morphological pattern of the cell masses and their relationship to the ventricular sulci were studied with the aid of a graphical reconstruction procedure termed topological analysis )cf. Nieuwenhuys, '74 and figs. 15, 16(. This analysis yielded the following results: The sulcus limitans extends throughout the rhombencephalon, dividing this brain part into a basal plate and an alar plate. The cell masses in the basal plate fit into two longitudinal zones, a medial area ventralis and a lateral area intermedioventralis. The area ventralis contains three somatic motor nuclei )IV, VI and XII( and the rhombencephalic medial reticular zone. The latter may be primarily considered as a somatic motor coordinating center. The area intermedioventralis contains the visceral motor nuclei of V, VII, IX and X. However, the basal plate also contains a number of non‐motor centers, for example the superior olive. The alar plate contains visceral sensory, general somatic sensory and special somatic sensory centers. Two cell masses, the nucleus fasciculi solitarii and the nucleus visceralis secundarius, represent together a discontinuous visceral sensory zone. Both of these nuclei are situated immediately dorsal to the sulcus limitans. The special somatic sensory area, i.e., the area of termination of the eighth nerve, occupies a considerable part of the alar plate. This area comprises, apart from a large zone of diffuse gray, three distinct cell masses. The general somatic sensory nuclei, i.e., the nucleus tractus descendens and the nucleus princeps of V, constitute a zone which largely overlaps the nucleus fasciculi solitarii and one of the octavus nuclei. In the frogs investigated the cell masses in the midbrain do not exhibit a clear‐cut morphological pattern. Functionally, however, the medial part of the tegmentum mesencephali may be considerd as the rostral extreme of the somatic motor area, whereas the lateral part of the tegmentum and the tectum are chiefly occupied by special somatic centers of primary and higher

ISSN:0092-7317    

DOI:10.1002/cne.901650304

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

年代:1976

数据来源: WILEY

摘要:

AbstractThe ventricular sulcal pattern and the cellular structure of the brain stem of the sharksSqualus acanthiasandScyliorhinus caniculahave been studied in transversely cut Nissl, Klüver‐Barrera and Bodian stained serial sections. Five longitudinal sulci, the sulcus medianus inferior, the sulcus intermedius ventralis, the sulcus limitans, the sulcus intermedius dorsalis and the sulcus medianus superior could be distinguished in both species. In addition to these long, principal grooves, a number of shorter, accessory sulci appeared to be present. Although the neuronal perikarya in many places display a diffuse arrangement, with the aid of the usual cytoarchitectonic criteria 34 cell masses could be delineated inSqualusand 30 inScyliorhinus. These cell masses can be distributed over the following categories )numbers added in brackets forScyliorhinus, if different from those inSqualus(: primary efferent or motor, 10 )9(; primary afferent or sensory, 7: reticular formation, 5; “relay” centers, 9 )8(; nuclei of unknown relationships, 3 )1(. Seven of the cell masses found inSqualusand four of those found inScyliorhinushave not been described before.The morphological pattern of the cell masses and their relationship to the ventricular sulci were studied with the aid of a graphical reconstruction procedure termed topological analysis )cf. Nieuwenhuys, '74, and figs. 24, 25(. This analysis yielded for both sharks the following results: A sulcus limitans extends from the spinal level to the pretrigeminal region. This sulcus divides the greater part of the rhombencephalon into a basal plate and an alar plate. In the basal plate the sulcus intermedius ventralis marks the boundary between an area ventralis and an area intermedioventralis. The area ventralis contains two somatic motor centers )i.e., the rostral end of the spinal motor column and the medial part of the nucleus of VI( and by far the greater portion of the rhombencephalic medial reticular formation. The latter may be primarily considered as a somatic motor coordinating center. The area intermedioventralis contains the visceral motor nuclei of X, IX, VII and V. However, the basal plate also harbours a number of non‐motor centers, for example the inferior olive and the nucleus funiculi lateralis. In the caudal half of the rhombencephalon the sulcus intermedius dorsalis subdivides the alar plate into an area intermediodorsalis and an area dorsalis. The area intermediodorsalis is largely occupied by the common visceral sensory center of X, IX and VII; however, this area also contains the general somatic sensory nucleus descendens of V and the nucleus vestibularis magnocellularis. The area dorsalis is entirely occupied by two large lateral line nerve centers. The cell masses in the isthmus region and in the mesencephalon do not exhibit a clear‐cut morphological pattern. Functionally, however, a number of centers in the medial part of the tegmentum mesencephali )nuclei of IV and III, nucleus of the f.l.m., nucleus ruber( may be considered as a rostral continuation of the rhombencephalic somatic motor area. Similarly, the nucleus of Edinger‐Westphal represents the visceral motor zone at the midbrain level. The lateral part of the tegmentum mesencephali contains the nucleus of the torus semicircularis and the nucleus tegmentalis lateralis. It is suggested that these two nuclei together constitute a zone of somatic sensory r

ISSN:0092-7317    

DOI:10.1002/cne.901650305

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

年代:1976

数据来源: WILEY

摘要:

AbstractCrayfish stretch receptor organs were used. The standard procedure consisted of primary fixation with a 1.6% glutaraldehyde solution containing either buffer which was 60% hyposmotic or buffer which was isosmotic with the physiological solution )440 milliosmols(, washing with isosmotic buffer, and postfixation with an isosmotic 1% osmium tetroxide solution. Under these conditions, we encountered two types of nerve terminals; small‐vesicle terminals )SVTs( containing small elongated vesicles )300 ∼ 330 Å( and largevesicle terminals )LVTs( containing larger round vesicles )430 Å(. Their location and physiological evidence suggest that SVTs and LVTs are inhibitory and excitatory, respectively. A hyperosmotic primary fixation solution due to increased glutaraldehyde concentration gave results similar to the standard procedures, while a hyperosmotic primary fixation solution due to increased buffer concentration caused shrinkage of the nerve terminal. A hyperosmotic buffer wash produced elongation of vesicles in SVTs and LVTs, while washing with hyposmotic buffer rendered vesicles in both types round. Direct fixation with isosmotic osmium tetroxide yielded less elongated vesicles in SVTs and irregularly round vesicles in LVTs. However, under all conditions, vesicles in SVTs were smaller than those in LVTs. These results suggest that the consistent morphological difference in vesicles between SVTs and LVTs is size rather than shape, and it is important to standardize the osmolarity of primary fixation and washing solutions when discussing the differences of vesicle shape in various kinds of syn

ISSN:0092-7317    

DOI:10.1002/cne.901650306

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

年代:1976

数据来源: WILEY

摘要:

AbstractThis report describes the fine structural features and distribution of the synaptic cluster )glomerulus( within the inferior olivary nucleus of the opossum. The postsynaptic elements typically include spiny appendages and small diameter dendrites which exhibit attachment plaques and gap junctions. Profiles presynaptic to the central core of postsynaptic elements were differentiated on the basis of vesicle shape, vesicle size, as measured by a computer system, and junctional characteristics. Three categories of terminals with clear vesicles are present within the synaptic clusters in all nuclear divisions of the olive, whereas a fourth with large dense core vesicles is restricted primarily to the principal nucleus. The groups of pre and postsynaptic elements are surrounded by astrocytic lamellae and are most frequently encountered in the principal and rostral portions of the medial accessory nuclei. Possible identification of the sources of the synaptic components is discussed in relation to data available from Golgi impregnations, physiological reports and hodological evidence.

ISSN:0092-7317    

DOI:10.1002/cne.901650307

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

年代:1976

数据来源: WILEY

ISSN:0092-7317    

DOI:10.1002/cne.901650301

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

年代:1976

数据来源: WILEY