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McBride, Russell L.; Sutin, Jerome
doi: 10.1002/cne.901650302pmid: 1270609
The 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.
Opdam, Paul; Nieuwenhuys, Rudolf
doi: 10.1002/cne.901650303pmid: 1270610
The ventricular sulcal pattern and the cellular structure of the brain stem of the axolotl Ambystoma mexicanum have 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.
Opdam, Paul; Kemali, Milena; Nieuwenhuys, Rudolf
doi: 10.1002/cne.901650304pmid: 1083857
The ventricular sulcal pattern and the cytoarchitectonic organization of the brain stem of the frogs Rana esculenta and Rana catesbeiana have 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 in Rana esculenta. With the aid of the usual cytoarchitectonic criteria 25 cell masses have been delineated in Rana esculenta and 27 in Rana catesbeiana. These cell masses can be distributed over the following categories )numbers added in brackets for Rana catesbeiana, if different from those in Rana 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.
Smeets, Wilhelmus J. A. J.; Nieuwenhuys, Rudolf
doi: 10.1002/cne.901650305pmid: 1270611
The ventricular sulcal pattern and the cellular structure of the brain stem of the sharks Squalus acanthias and Scyliorhinus canicula have 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 in Squalus and 30 in Scyliorhinus. These cell masses can be distributed over the following categories )numbers added in brackets for Scyliorhinus, if different from those in Squalus(: 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 in Squalus and four of those found in Scyliorhinus have not been described before.
Tisdale, Ann D.; Nakajima, Yasuko
doi: 10.1002/cne.901650306pmid: 773968
Crayfish 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 synapses.
doi: 10.1002/cne.901650307pmid: 1270612
This 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.
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