摘要:

AbstractAmygdaloid and pontine projections to the feline ventromedial nucleus of the hypothalamus (HVM) were studied with retrograde transport of horseradish peroxidase (HRP) and anterograde transport of tritiated amino acids. Following injections of HRP into HVM, amygdaloid neurons were labeled in the ipsilateral cortical and medial nuclei and the ventral portion of the parvocellular part of the basal nucleus. In experiments in which HRP was injected into the tuberal hypothalamus following stria terminalis lesions, it was determined that amygdaloid neurons projecting to HVM by way of the stria terminalis were located in the cortical and medial nuclei while those projecting through another route, presumably the ventral amygdalofugal pathway, were found in the rostral part of the medial nucleus and the parvocellular basal nucleus.Following HRP injection into lateral hypothalamus at the level of HVM, labeled neurons were seen in the magnocellular basal nucleus. After preoptic injections, neurons containing the HRP reaction product were in cortical and medial nuclei and magnocellular and parvocellular parts of the basal nucleus.In addition to cells in the amygdala, rostral pontine neurons were labeled after HRP injections into HVM. The cells were located ipsilateral to the injection, mostly in the dorsal nucleus of the lateral lemniscus, lateral and dorsolateral to the brachium conjunctivum. The pontine cells labeled following HVM injections of HRP were different from those labeled following lateral hypothalamic and preoptic region injections. The pontine projection to HVM was confirmed using axoplasmic transport autoradiography. A mixture of tritiated leucine and tritiated proline was injected into the lateral pontine region labeled after HRP injections into HVM. Labeled axons ascending in the medial forebrain bundle terminated throughout the rostro‐caudal extent of HV

ISSN:0092-7317    

DOI:10.1002/cne.901740302

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

年代:1977

数据来源: WILEY

摘要:

AbstractThe synthesis and distribution of3H‐leucine labeled protein was studied under conditions of diurnal lighting in the retinula cells of the crayfish retina with both light and electron microscopic autoradiography. Times ranging from two minutes to seven days after an intracardiac injection were analyzed. Quantification of the electron microscopic autoradiograms revealed that labeling of the cytoplasm was greater than the rhabdome at 2, 5, and 30 minutes and reached a peak at 12 hours. The rhabdome showed increasing activity after 5, 30, and 60 minutes, also reaching a peak at 12 hours. Radioactive label in cytoplasmic multivesicular bodies was higher than activity measured in either the total cytoplasm or rhabdome at all times except two minutes.Two temporally different microvillar labeling patterns were seen under diurnal lighting conditions. (1) Microvilli forming the slightly enlarged distal tip of the rhabdome retained their radioactivity at 1, 3, and 7 days, when labeling of the rest of the rhabdome microvilli was decreasing. (2) In the remainder of the microvilli, labeling at 1 and 12 hours appeared as a gradient which declined toward the proximal end of the rhabdome. This gradient subsequently reversed itself, showing heavier proximal labeling at three days.In a second experiment, labeling patterns in light and dark adapted rhabdomes were compared. In the dark, a distinct gradient of activity was observed with radioactivity concentrated distally and declining toward the proximal end of the rhabdome. A more even distribution of label was present in the light adapted eye, but a slight distal‐proximal gradient was still present. The dark adapted rhabdomes had more radioactivity per unit area than those exposed to li

ISSN:0092-7317    

DOI:10.1002/cne.901740303

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

年代:1977

数据来源: WILEY

摘要:

AbstractAfter lesions of inferior olive, survival times of 5 to 12 days and Nauta staining, degeneration is present in white matter and central cerebellar nuclei and Deiters' nucleus. Shorter survival times from 40 to 60 hours and Fink‐Heimer impregnation reveal degenerating climbing fiber terminals in the molecular layer. With3H‐leucine autoradiography and survival times of three to seven days the entire trajectory of the climbing fibers can be traced. Olivocerebellar fibers cross in the brain stem and terminate contralaterally in cortex and central nuclei. Occasional labeling of mossy fiber terminals is explained by involvement of reticular nuclei.Small parts of the inferior olive connect with narrow longitudinal zones in the cortex through compartments in the white matter. The corresponding distribution of olivocerebellar fibers and Purkinje cell axons over these compartments suggests that the organization of the olivocerebellar and corticonuclear projection is essentially similar. Collaterals always terminate in the central cerebellar necleus which receives a corticonuclear projection from the zone in which the parent fibers terminate.Caudal medial accessory olive projects to medial vermal zone A and to fastigial nucleus, subnucleus beta projecting to lobule VII and caudal fastigial nucleus. Cadual dorsal accessory olive projects to lateral vermal zone B in lobules I‐VI, Deiters' nucleus and dorsomedial subnucleus of interposed nucleus. The caudal principal olive (dorsal cap, ventrolateral outgrowth receiving visual and vestibular input) projects to flocculo‐nodul

ISSN:0092-7317    

DOI:10.1002/cne.901740304

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

年代:1977

数据来源: WILEY

摘要:

AbstractThis study provides basic data on the normal structure of the inferior olivary nucleus of the rat at both the light and electron microscopic level. The cytoarchitecture of the nucleus was mapped in serial sections cut in the transverse plane and stained with cresyl violet. The bulk of the inferior olive is composed of the princpal olive and the dorsal and medial accessory olives. The dorsal cap, nucleus β, ventrolateral outgrowth and dorsomedial cell column are minor subgroups of cells which are clearly represented in the nucleus.Golgi preparations revesled two types of dendritic pattern both of which are found in the principal olive and in the accessory olives. Portions of the dendritic tree are varicose in appearance and bulbous expansions, often bearing spines, are pendage may be observed; namely, simple spines, pedunculatd club‐shaped spines, and racemose appendages. Appendages are most numerous in association with distal portions of th dendritic tree.Analysis of the principal olive of the principal olive and of the accessory olives with the electron microscope revealed the following characteristics: Round vesicle terminals which are the predominat type found in the nucleus range in size from 0.3 μm. to 4.0 μm. Pleomorphic vesicle terminals range in size from 0.5 μm to 3.5 μm. Both types of terminal are ubiquitous in their distribution with regard to the dendritic tree of olivery neurons but are more numerous in relation to dendritic elements measuring less than 2 μm in diameter. Axosomatic synapses and synapses on proximal dendrites are few in number and are made by both types of terminal. A third type of terminal which contains up to 25% dense core vesicles is found infrequently in all three major subnuclei. Much of the surface of the soma of olivary neurons is covered with glial cell processes or by dendritic elements. No membrane specialization is found between these apposed surfaces.Dendritic spines, some of which contain a well marked spine apparatus, are commonly seen and appear to correspond to the pendunculated club‐shaped spines seen in the Golgi preparations. Other large dendritic profiles which are packed with mitochondria are considered to possibly correspond to the varicose dilations of the dendrites or to “bleb‐like” protrusions of dendritic shafts seen in Golgi preparationsGlomerulus‐like structures are seen in the neuropil and have been shown to possess a core of small dendritic elements which are contacted at their pertially surrounded by glial cell processes and has been termed asynaptic cluster. Such axo‐dendritic complexes are largest and most numerous in the principal olive and rostral half of the medial accessory olive. In some planes of section, it is possible to trace the dendritic core of the synaptic cluster back to a larger dendritic shaft. It is suggested that such dendritic cores correspond to the racemose appendages which are seen in Golgi preparations.Gap junctions and attachment plaques are frequently seen between dendritic elements in synaptic clusters and also between dendritic elements which are not part of synaptic clusters, in all three major subnuclei. In the medial accessory olive, several examples of two gap junctions arranged in series between three small dendritic elements

ISSN:0092-7317    

DOI:10.1002/cne.901740305

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

年代:1977

数据来源: WILEY

摘要:

AbstractThermal lesions were made in layers I, II, and upper part of layer III of rat visual cortex. The distribution of degenerating axons and axon terminals in layers IV, V, and VI was studied using electron microscopic techniques.Following supragranular thermal lesions, the majority of degenerating axon terminals were found in layer V, with extension into the adjacent part of layer VI. Neural profiles postsynaptic to degenerating axon terminals were found in these layers in the following distribution: 81.7% on spines of small to medium size dendrites; 18.2% on dendrite shafts; and<1% on neuronal perikarya. Few degenerating terminals were found on or near apical dendrites. Degenerating terminals were identified on shafts of stellate‐type dendrites found in the upper part of layer V.Degenerating axons oriented parallel to the cortical surface were found most often in deep layer IV and upper layer V. Degenerating axons were also seen in axon bundles coursing vertically through layer IV.Approximately 10% of the terminals within a grid square have undergone degeneration; no clustering of degenerating terminals was found in vertical or transverse sections through layers V and VI.We suggest that most axon terminals arising from pyramidal neurons in layers II and upper III synapse with spines and shafts of dendrite branches originating from pyramidal neurons in layer V and perhaps V

ISSN:0092-7317    

DOI:10.1002/cne.901740306

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

年代:1977

数据来源: WILEY

摘要:

AbstractBy anatomical techniques it has been shown that folia VIc‐IXc of the pigeon cerebellum receive inputs from the following groups of neurons: the medial and lateral pontine nuclei, the superficial synencephalic nucleus, the medial spiriform nucleus, the inferior olive, and the deep cerebellar nuclei. From all but the last of these, the projection is mainly crossed, though the uncrossed component from the lateral pontine nucleus is not insubstantial. The input from the superficial synencephalic nucleus provides a direct pathway from the retina to the cerebellum (folia VIc, VII, VIII and IXc). Less direct visual pathways reach the cerebellum via the following routes: (i) the superficial synencephalic nucleus projects ipsilaterally to the lateral pontine nucleus and sparsely to the inferior olive; (ii) the tectum projects ipsilaterally to the lateral and medial pontine nuclei, though the latter connection is sparse.In electrophysiological experiments, the importance of the tecto‐pontine component of the projection has been demonstrated by cooling the tectum while recording visual responses from the cerebellum. The visual receptive fields of pontine cells have been analysed. They vary in extent from 10° to the whole monocular field. They respond best to moving targets, preferring speeds of 20 to 60°/second, and are usually direction‐se

ISSN:0092-7317    

DOI:10.1002/cne.901740307

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

年代:1977

数据来源: WILEY

ISSN:0092-7317    

DOI:10.1002/cne.901740301

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

年代:1977

数据来源: WILEY