摘要:

AbstractAn atlas of the distribution of cholinergic cell bodies, fibers, and terminals, as well as cholinoceptive cells, in the central nervous system of the cat (excluding the cerebellum) is presented from results obtained in immunohistochemical work on choline acetyltransferase. Cholinergic cell bodies are observed in more than forty areas, and cholinoceptive cells in sixty discrete areas of brain sections from the spinal cord to the olfactory bulb. The atlas is presented in seventy cross‐sectional drawings of cat brain extending from the olfactory bulb to the upper cervical spinal cor

ISSN:0092-7317    

DOI:10.1002/cne.902000202

出版商:Alan R. Liss, Inc.    

年代:1981

数据来源: WILEY

摘要:

AbstractThe population of motorneurons which send axons to the metathoracic leg of the locust embryo has been stained by a cobalt backfilling technique. Embryogenesis lasts 11 days and an adultlike distribution of motorneuron cell bodies is seen as early as day 6: Several identified adult motorneurons can be recognized in the embryo. The total number of filled cells, the overall distribution of stained cell bodies, and the relative positions of identified neuron cell bodies do not change between 6 days and hatching. No motorneurons are stained which are clearly not leg motorneurons, and an adult pattern ofaxon branching at the level of peripheral nerve roots is already present at day 6. These observations provide information about the timing of motorneuron production and motor axon growth into the embryonic limb. The development of central dendritic arborizations can also be followed. The results are discussed with respect to mechanisms for neuron determination and differentiation.

ISSN:0092-7317    

DOI:10.1002/cne.902000203

出版商:Alan R. Liss, Inc.    

年代:1981

数据来源: WILEY

摘要:

AbstractSegments of the occipital cortex were taken from rat embryos (E16–E19) and transplanted to the cerebral cortex or the tectal region ofa new‐born rat host. With the aid of Golgi impregnation techniques, neuron morphology was studied in cortical transplants which had survived for 1 week or more in the host brain. In mature transplants (>4 weeks) three main groups of neurons, termed groups I–III, were identified. Group II neurons resembled pyramidal neurons of the intact cerebral cortex. No preferential orientation of either soma or dendrites of group I neurons was observed in the transplants, and some group I neurons was observed in the transplants, and some group I neurons had curved spical dendrites. Group II neurons had predominantly stellate form and their dendrites were densely covered with spines. Paucity or absence ofdendritic spines characterized group III neurons which exhibited various dendritic topologies.Different neuron types were also recognized in immature transplants growing for 1 and 2 weeks in the host brain. The sequence of dendritic maturation of transplanted cortical neurons is similar to that seen in intact cortex, although the stage reached related more to the actual age of the transplant than to that of the host. Thus, group I neurons in the 1‐week‐old transplants taken from E16 embryos had not attained the same complexity of branching as pyramidal neurons in the surrounding host cortex, but rather resembled slightly younger cells more like those found in the cerebral cortex of the newborn rat.These results show, therefore, that at least the basic cell classes identified in intact visual cortex can also be recognized in the cortical transplants. This will provide a foundation for studies defining which cells project to the host brain and which are involved in particular intrinsic co

ISSN:0092-7317    

DOI:10.1002/cne.902000204

出版商:Alan R. Liss, Inc.    

年代:1981

数据来源: WILEY

摘要:

AbstractWe have studied the projections from the superior colliculus and the neocortex to the pulvinar nucleus inGalago senegalensis. by using the retrograde transport of horseradish peroxidase (HRP). Injections of various parts of the pulvinar complex, both the inferior and superior divisions, both the tectorecipient zone and the nontectorecipient zone as defined by Glendenning et. al. ('75), produce labeled cells in the lower tier ofstratum griseum superficiale. The distribution of labeled cells in the superior colliculus varies with the locus of the injection, indicating a retinotopic projection system from the entire superior colliculus to all sectors of the pulvinar complex.These experiments also provide an opportunity to study the distribution and laminar origin ofneurons giving rise to cortical descending projections. The entire visual cortex projects onto the pulvinar complex. The cells of origin can be divided into two populations–one located in layer V and the other in layer VI. In seven of the nine cases reported, the layer V population is restricted entirely or mainly to the striate area. In the two exceptional cases, the layer V population is located in the adjacent extrastriate cortex, areas 18 and 19. The difference in the layer of origin of the cortical descending fibers reflects a difference in the layer of termination of the reciprocal ascending projection.These findings identify the entire visual field as primary visual cortex. The importance of this conclusion is underscored by the fact that the visual field comprises as much as one‐half of the whole neocor

ISSN:0092-7317    

DOI:10.1002/cne.902000205

出版商:Alan R. Liss, Inc.    

年代:1981

数据来源: WILEY

摘要:

AbstractThe organization of vestibulocerebellar projections to the flocculonodular and adjacent cortices were studied in Galago using horseradish peroxidase (HRP). Implants of HRP pellets or injections (0.14–0.95μI) were placed in floccular, parafloccular, nodular, and uvular cortices. Following survival times of 18–25 hours animals were killed via transcardiac perfusion of heparinized saline followed by a buffered solution of paraformaldehyde and glutaraldehyde. Tissues were processed using DAB as the chromogen.Consequent to floccular implants HRP‐positive cells are found bilaterally in medial (MVN), spinal (SpVN), and superior (SVN) vestibular nuclei. Labeled neurons are present in the ipsilateral subgroup y and interstitial nucleus of the eighth nerve. The prepositus hypoglossal nuclei also contained HRP‐positive somata. A column of labeled cells is present exclusively in dorsomedial MVN subsequent to injection of the paraflocculus. Injections of nodular cortex reveal a distinct bilateral projection to this cortical area. Many labeled cells are located in SpVN, MVN, SVN, subgroups x and y, the interstitial nucleus, and the ganglion of the eighth nerve. Labeled somata are concentrated in dorsal and dorsolateral SpVN and in a bandlike configuration in subgroup x. HRP‐reactive cells appear to have a differential rostrocaudal distribution in MVN, while the majority of positive cells in SVN are found in central portions of the nucleus. After HRP injection into the transition area between nodular and uvular cortices, labeled neurons are present in MVN, SpVN, and the prepositus hypoglossal nucleus. A similar distribution of HRP‐positive cells is seen following injections of ventral uvula; however, cells are markedly fewer in number. In no case, subsequent to injection of the flocculonodular lobe and adjacent cortices, are HRP‐labeled neurons found in the lateral vest

ISSN:0092-7317    

DOI:10.1002/cne.902000206

出版商:Alan R. Liss, Inc.    

年代:1981

数据来源: WILEY

摘要:

AbstractEarly neurogenesis was studied in two series of mouse embryos with tritiated thymidine (3H‐Tdr) autoradiography to determine (1) the time of origin and (2) the identity of the first postmitotic neurons. Time of origin was studied in embryos cumulatively labeled on the 9th–11th day of gestation (E8, E9, or E10, since the day of finding the vaginal plug is EO) and terminated after one cell cycle (8 hours). Autoradiographs were examined for unlabeled neurons, those which had undergone final DNA synthesis and which were usually also postmitotic. A 16‐somite embryo, cumulatively labeled from the 6‐somite stage, demonstrated 234 such cells in both alar and basal plates from the caudal diencephalon to the cervical spinal cord. Some of these young neurons, therefore, arose prior to neural tube closure, which begins at the 7‐somite stage. Data from other embryos in this series suggests that the first neurons arise at the 1–2 somite stage.Early arising neurons were identified in embryos pulse labeled with3H‐Tdr during E8–11 and killed after postnatal day (P) 30, when neuronal types could be determined. Autoradiographs were examined for heavily labeled cells, those in final DNA synthesis at the time of treatment. Heavily labeled cells in the youngest mouse in this series (injected at E8½; ca. 8‐somite stage) were primarily small‐to medium‐sized neurons of the brainstem reticular formation, but also some small neurons of the superior olivary nucleus and large primary sensory neurons of the mesencephalic nucleus of the trigeminal nerve. The earliest neurons in the spinal cord appeared early on E9, were medium sized, and were located in the ventral horn and the intermediate zone.Comparisons between the results of this study and those of McConnell and Sechrist ('80) in the chick suggest that the youngest stages of neurogenesis are similar. The first chick nerve cells arise just before formation of the first somites; a slightly later time is indicated in the mouse. Reticular neurons are the earliestarising cells in the chick and make up the majority of the population in each of the youngest chick and mouse stages obtained. Motor and sensory neurons do not begin to originate in large numbers until later, during E3 in the chi

ISSN:0092-7317    

DOI:10.1002/cne.902000207

出版商:Alan R. Liss, Inc.    

年代:1981

数据来源: WILEY

摘要:

AbstractA combined formaldehyde‐induced fluorescence (FIF)‐autoradiography procedure was used to determine how and where the androgen, dihydrotestosterone (DHT), is associated with catecholamine systems in the rat brain. With this dual localization method, (3H)‐DHT target sites can be visualized in relation to catecholamine perikarya and terminals. In the hindbrain, catecholamine neurons adjacent to the fourth ventricle (group A4), the nucleus (n.) olivaris superior (group A5), the n. parabrachialis medialis (group A7), and in the locus coeruleus (group A6) and subcoeruleal regions, as well as in the substantia grisea centralis, concentrate (3H)‐DHT in their nuclei. (3H)‐DHT target neurons appear to be innervated by numerous catecholamine terminals in the following hindbrain regions: n. motorius dorsalis nervi vagi, n. tractus solitarii, n. commissuralis, n. raphe pallidus, n. olivaris inferior, the ventrolateral portion of the substantia grisea centralis, n. cuneiformis, and the ventrolateral reticular formation in the caudal mesencephalon. In the forebrain, (3H)‐DHT concentrates in nuclei of catecholamine neurons located in the n. arcuatus and n. periventricularis (group A12). In addition, (3H)‐DHT target neurons appear to be innervated by numerous catecholamine terminals in the following forebrain regions: n. periventricularis rotundocellularis, n. paraventricularis, n. dorsomedialis, n. periventricularis, area retrochiasmatica, n. interstititalis striae terminalis (ventral portion), and n. amygdaloideus centralis.The disclosure of a morphologic association between (3H)‐DHT target sites and certain brain catecholamine systems suggests a close functional interdependence between androgens and

ISSN:0092-7317    

DOI:10.1002/cne.902000208

出版商:Alan R. Liss, Inc.    

年代:1981

数据来源: WILEY

ISSN:0092-7317    

DOI:10.1002/cne.902000201

出版商:Alan R. Liss, Inc.    

年代:1981

数据来源: WILEY