摘要:

AbstractThe fine structure of the olfactory bulb was investigated in the cat. Five types of bulbar neurons were identified on the basis of size, location, cytoplasmic organelles and synaptic complexes with the neuron perikaryon. The smallest diameter neurons were predominatly located in the glomerular and granule cell layers. Ultrastructural characteristics for these two neuron populations, viz., periglomerular and internal granule cells, were identical. Tufted cells, smaller in diameter than mitral cells, were located in the external plexiform and glomerular layers and possessed all the morphological characteristics of the mitral cells. Mitral cells were the largest bulbar neurons and were located in a single lamina. Stellate (short‐axon) neurons were found in the glomerular, external plexiform and granule cell layers.Reciprocal synapses were observed in all laminae of the bulb except the primary olfactory nerve and deeper granule cell layers. Such synapses were found in the glomeruli, on tufted and mitral cells, in the neuropil of the external plexiform layer, and on the axon hillock and initial segments of the mitral cells. The morphology in the cat olfactory bulb corroborated bulbar ultrastructure described for other mammal

ISSN:0092-7317    

DOI:10.1002/cne.901520302

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

年代:1973

数据来源: WILEY

摘要:

AbstractThe organization of the efferent fiber systems of the nurse shark cerebellum was studied with the Nauta and Fink‐Heimer techniques. Lesions of the cerebellar cortex produce a pattern of terminal degeneration restricted to select regions of the cortex, as well as ipsi‐ and contralateral cerebellar nuclei. We found no evidence of cortical axons projecting beyond the nuclei, to the medulla and spinal cord as has often been reported.Lesions involving the cerebellar nucleus reveal three efferent pathways. The ipsilateral descending cerebello‐bulbar (IDC) pathway extends as far caudal as the first spinal segment and issues fibers to the lateral parts of the reticular formation. The brachium conjunctivum splits into a larger ascending limb (BCA) and a smaller descending one (BCD). The latter descends to the caudal medulla terminating along its course in the medial reticular formation. The ascending limb provides an input to (1) a nucleus we have tentatively labelled the “red nucleus,” (2) the trochlear nucleus, (3) the oculomotor nuclei, (4) the midbrain central gray, and (5) a poorly differentiated nucleus in the dorsal

ISSN:0092-7317    

DOI:10.1002/cne.901520303

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

年代:1973

数据来源: WILEY

摘要:

AbstractThe lamina ganglionaris in the crayfish is composed of two cell layers and three acellular fibrous zones. The cells composing the layers above the acellular synaptic region (SR) show two distinct nuclear types in light microscopy and two cytoplasmic types with EM. Golgi impregnations of the lamina revealed three groups of elements which contribute processes to the SR; retinula axons from the retina, monopolar elements from the cell layers above the SR and horizontal elements whose perikaryal location is uncertain. Retinula elements terminate at various levels within the SR forming large irregular baglike terminals. Monopolar cells have a single axial fiber with numerous lateral processes which extend across the SR in a veriety of patterns. Horizontal elements have a more extensive lateral spead within the SR than monopolar processes. Electron microscopic data show the retinula terminal bags and monopolar processes to be organized into cartridge units at the superficial levels of the SR. Each cartridge consists of four enlarged terminals, three retinula axons and four to six central moncpolar processes. At deeper levels of the SR, the cartridge arrangement is not evident and the large terminals appear arranged in rows. Specialized synaptic contacts are found along the central borders of the retinula terminals.

ISSN:0092-7317    

DOI:10.1002/cne.901520304

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

年代:1973

数据来源: WILEY

摘要:

AbstractThe posterior lateral line lobe is a rhombencephalic laminated structure. There is a topographic projection of anterior and posterior lateral line nerves upon the posterior lobe. The six separate lamina of the posterior lobe contain at least six cell types which can be distinguished on the basis of their dendritic trees. One lamina, the plexiform layer, contains the collateral plexus of the lamina of ganglion cells. There is an asymmetry in the dendritic fields and in the collateral plexus of neurons of the posterior lobe, such that their long axis runs in the sagittal plane.There is an extensive projection from granule cells of lobus caudalis to the posterior lobe molecular layer. This connection is organized in a fashion similar to that of the parallel fiber system of the cerebellum, i.e., the axons form an inverted T, the arms of which run parallel to the granule cell layer. This projection is confined to the upper part of the molecular layer, while the lower part of the molecular layer contains the axons arising in the posterior lobe granular layer.

ISSN:0092-7317    

DOI:10.1002/cne.901520305

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

年代:1973

数据来源: WILEY

摘要:

AbstractThe morphology of the inferior olivary complex was determined in the rhesus monkey (Macaca mulatta). The position, configuration, and relations of each of its components were ascertained in serial transverse sections extending from caudal through rostral poles of the complex. The medial accessory nucleus was divided into seven cell groups (labeled a through g). The principal nucleus consisted of well‐developed dorsal, ventral, and lateral lamellae and a criterion was established for distinguishing the boundaries of each. This distinction was based upon the pattern of invagination that developed in the principal nucleus in progressing rostrally from its caudal pole. The dorsal and lateral lamellae each presented a characteristic pattern of major invaginations, while the ventral lamella did not. Finally, a detailed comparison was made of the inferior olivary complex of the monkey with that of the cat as determined by other investigators. It was shown that the medial and dorsal accessory nuclei of the two species appeared similar and that the major difference between these species concerns the principal nucleu

ISSN:0092-7317    

DOI:10.1002/cne.901520306

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

年代:1973

数据来源: WILEY

ISSN:0092-7317    

DOI:10.1002/cne.901520301

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

年代:1973

数据来源: WILEY