摘要:

AbstractIndoleamine structures in the brains of normal, pair‐fed control, and thiamine deficient rats are selectively localized by autoradiography following monoamine oxidase inhibition and simultaneous intraventricular infusion of3H‐5HT (10−5m) and cold d–1 norepinephrine (10−4m). The locations of indoleamine neurons and their plexuses are comparable in the normal and control animals and are enumerated and mapped in detail. In addition to numerous labeled neurons in the raphe and reticular formation of pons and medulla, there are indoleamine neurons in several hypothalamic nuclei, in the mammillary, habenular, and interpeduncular nuclei. Labeled axonal plexuses occur in almost all areas of the brain but certain regions in spinal cord, medulla, midbrain, diencephalon, basal ganglia, and hippocampus are particularly rich. Thiamine deficiency causes lack of label in almost all indoleamine neurons and their processes in the midbrain and medulla; only a few dystrophic cells with hypertrophied axons are seen. In the diencephalon more indoleamine neurons and their axonal plexuses are visualized in these uptake studies. The periventricular regions of spinal cord, medulla, midbrain and diencephalon, the mammillary nuclei, habenular nuclei, and cerebellum – areas richly innervated by indoleamine axons in the normal brain – are the most severely affected. The ventricular and leptomeningeal indoleamine structures are preserved, however, and individual axons may hypertrophy. It remains to be resolved whether these changes reflect disturbances in the ability of certain indoleamine neurons to take up and retain3H‐5HT or true neuron

ISSN:0092-7317    

DOI:10.1002/cne.901760402

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

年代:1977

数据来源: WILEY

摘要:

AbstractThe commissural connections of the hippocampus (fascia dentata and Ammon's horn) were investigated in the rabbit using a Fink‐Heimer silver impregnation method after the transection of either or both hippocampal commissures. In some cases additional sections were processed either with a histochemical method for acetyl cholinesterase or with the Timm‐Haug sulfide silver method.The fibers to thefascia dentataarrive through the ventral commissure and terminate in a juxtagranular zone that corresponds to a relatively pale zone in acetyl cholinesterase preparations and to a dark zone in Timm‐Haug sulfide silver preparations. The degeneration is more dense in the middle of the Ushaped cross‐sectional profile of the fascia dentata than at the edges. This is particularly evident in the ventral portion of the fascia dentata. There is no evidence of commissural terminals in the layer of polymorphic cells. The commissural fibers to theAmmon's hornpass through both commissures. The fibers in thedorsal commissureterminate in the strata radiatum, oriens and pyramidale at their transition to the subiculum, in the septal part of the Ammon's horn. The molecular layer contains relatively little degeneration after transection of the dorsal commissure with the exception of the crossed entorhinal efferents to the rostral part. Fibers from theventral commissureterminate in both the stratum oriens and the stratum radiatum. The degeneration in the stratum oriens is dense through the full extent of the layer, while that in the stratum radiatum is maximal in the regio inferior near the fimbria and less dense close to the fascia dentata and in the regio superior, with the exception of the antero‐rostral extreme of the latter. The density of degeneration in the stratum radiatum diminishes in the postero‐ventral direction except for degeneration at the subicular and dentate ends of the layer.Evidence is presented for a powerful ipsilateral longitudinal association path terminating in the stratum radiatum of the regio inferior and in a minor adjacent portion of the dentate commi

ISSN:0092-7317    

DOI:10.1002/cne.901760403

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

年代:1977

数据来源: WILEY

摘要:

AbstractWhen retino‐geniculate axons of mink are labelled with3H proline, the laminar structure of the dorsal lateral geniculate nucleus is seen to resemble that previously described in the cat. Layers A, C and C2 receive a crossed input and layers A1 and C1 receive an uncrossed input. The parvocellular layer C2 is relatively thicker in the mink than it is in the cat, and studies of retino‐geniculate fiber degeneration show that it receives fine caliber retinal afferents, whereas layers A and C receive mainly coarse afferents. The medial interlaminar nucleus receives two quite distinct crossed retino‐geniculate inputs. There is a coarse fibered component, which is continuous with lamina C, and a fine fibered component, continuous ventrolaterally with lamina C2 and extending rostro‐dorsally as a narrow streak along the margin of the nucleus lateralis posterior. The uncrossed afferents to lamina A1 are as coarse as the crossed axons to layers A and C. The uncrossed afferents to lamina C1 are somewhat finer, but are not as fine as the afferents to lamina C2. There are not many uncrossed fibers to the medial interlaminar nucleus and the distinction between coarse and fine components is not shown clearly. However, it is possible to recognize fine axons extending towards the margin of the nucleus lateralis posterior. We interpret these results as showing that there are two functionally distinct inputs to the medial interlaminar nucleus, and that the rest of the lateral geniculate nucleus may be divided into two distinct systems: A magnocellular, receiving coarse axons, and a parvocellular, receiving fine axons. The magnocellular system has one “ipsilateral” layer (A1) flanked by two “contralateral” layers (A and the dorsal part of C), while the parvocellular system similarly consists of a single “ipsilateral” layer (C1) flanked by two “contralateral” layers (C2 and

ISSN:0092-7317    

DOI:10.1002/cne.901760404

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

年代:1977

数据来源: WILEY

摘要:

AbstractThe inferior olivary complex (IOC) of marsupials was investigated to determine if correspondence exists between the IOC of marsupials and the IOC of eutherian mammals. We examined serial sections of the IOC of members of the eight major marsupial families: Didelphidae (Didelphis virginana,Philander opossum,Marmosa murina, andCaluromys sp.), Caenolestidae (Caenolestes obscurus and Lestoros inca), Dasyuridae (Antechinus flavipes,Dasyurus viverrinusandSarcophilus harrisii), Peramelidae (Isodon obesulusandPerameles nasuta), Phalangeridae (Trichosurus vulpeculaandPseudocheirus peregrinus), Petauridae (Schoinobates volansandPetaurus breviceps), Vombatidae (Vombatus ursinus) and Macropodidae (Potorous tridactylus,Setonix brachyurus,Macropus eugeniiandMacropus rufus).Evidence is presented that the principal nucleus (PIO) and dorsal nucleus (DIO) of the marsupial IOC are directly comparable to nuclei in eutherians. Nauta degeneration studies on the pattern of termination of spinal and rubral afferents inTrichosurus vulpeculasupport arguments for homology between the PIO and DIO of marsupials and of eutherians. However the probable homologue of the eutherian medial nucleus (MIO) has certain features that are unique to marsupials; while it can be divided into the same subnuclei found in eutherians (subnuclei a, b, c and the cap of Kooy) most of the cells of the marsupial medial nucleus homologue are locatedlateralto the PIO. The few cells of the MIO homologue that lie medial to the PIO are connected in some marsupials to the main lateral portion by a sheet of cells that lies ventral to the PIO. For this reason we propose that the medial nucleus homologue be named the ventral nucleus (VIO) in marsupials. Because of the ventral position occupied by medial nucleus cells during development in both eutherian and marsupial mammals, the term VIO could also be properly applied to the eutherian MIO as well.

ISSN:0092-7317    

DOI:10.1002/cne.901760405

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

年代:1977

数据来源: WILEY

摘要:

AbstractThe torus semicircularis (TS) of the Tegu lizard extends from the superficial caudal mesencephalon, dorsal to the exiting trochlear nerve, to a position ventral to the middle part of the optic tectum and its ventricle. It has an oblique orientation with the caudal pole abutting the midline while the rostral end is lateral and slightly ventral. The TS consists of a central nucleus and several adjacent cell groups. The central nucleus and the laminar nucleus, situated medially, extend the entire length of the TS while the cortical nucleus, situated dorsally and laterally, is present only in the caudal superficial portion. The central nucleus is composed of ovoid neurons with branched, radiating dendrites. The dendrites are directed medially and laterally with spines on the distal portion of the dendritic tree. The laminar nucleus consists of three to five neuronal layers. It is mainly composed of fusiform neurons with one dendritic trunk from each extremity of the soma. There is little branching and few dendritic spines.The cortical nucleus is a laminated region consisting of alternating layers of neurons and lateral lemniscal fibers. The neurons of the superficial layers are fusiform with their long axis perpendicular to the long axis of the brainstem. They possess two main dendritic trunks which parallel the laminae and are covered with dendritic spines. The deeper layers consist of pyramidal neurons with three dendritic trunks, secondary branches, and few spines. The long axis of these neurons extends from the center of the TS to the periphery. Two dendritic trunks extend dorsally or laterally towards the surface, while the third extends towards the central nucleus. The dendrites, thus, extend across the laminae. In addition, a cell‐free lateral zone is describe

ISSN:0092-7317    

DOI:10.1002/cne.901760406

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

年代:1977

数据来源: WILEY

摘要:

AbstractThe cerebellum of the premetamorphic bullfrog tadpole differs from the cerebellum of other frog species in its morphology and maturational state. The cell mass beneath the floor of the lateral recess and bordering its lateral wall that has been reported to form the auricular lobe in other species is absent, the auricular lobe abutting the medial wall of the lateral recess instead and is continuous with the corpus cerebelli. The corpus cerebelli, although immature and yet to acquire an external granular layer, is already massive and displays an incipient molecular, Purkinje cell and granular layers.Cytodifferentiation in the auricular lobe and corpus cerebelli is similar, their constituent cells being in various stages of development. Fully mature cells are absent, but a small population of Purkinje cells and glia in the auricular lobe and along the marginal zone of the corpus cerebelli show advanced development. The orientation of these Purkinje cells is parallel to the pia and appears to approximate the course of the vestibulo‐lateral commissural fibers. In the ventral part of the corpus cerebelli, developing climbing fibers are present but Purkinje cells are poorly develope

ISSN:0092-7317    

DOI:10.1002/cne.901760407

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

年代:1977

数据来源: WILEY

摘要:

AbstractThe rate of acquisition of visual form discriminations in cats with superior colliculus damage was measured in a testing apparatus requiring a minimal amount of stimulus localization in space. In animals with bilateral superior colliculus ablations, acquisition was impaired relative to acquisition in normal animals. In these animals, the extent of the lesion was related to the severity of the deficit. In split‐brain preparations with unilateral superior colliculus ablations, acquisition with the eye ipsilateral to the lesion was impaired relative to acquisition with eye contralateral to the lesion. The deficits observed did not depend upon damage to pretectum. The results support the conclusion that the superior colliculus participates in certain aspects of form visio

ISSN:0092-7317    

DOI:10.1002/cne.901760408

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

年代:1977

数据来源: WILEY

摘要:

AbstractIn the anophthalmic mutant of the mouse the optic primordia are “genetically enucleated” well before the usual emergence of retinal ganglion cell axons (Silver and Hughes, '74). In eyeless animals, a portion of the mediobasal hypothalamus and one of its constituent nuclear pairs, nucleus suprachiasmaticus (SCN), were markedly abnormal in the embryo and adult. It has been reported that the ventral portion of the SCN receives a substantial, direct retinal innervation (Moore and Lenn, '72) and that these nuclei may mediate several light‐induced hormonal and behavioral circadian rhythms (Stetson and Whitmyre, '76). During day 13 of mutant embryogenesis, just prior to the time of optic chiasm formation in normal animals, a large portion of ependyma and adjacent brain tissue herniated into the lumen of the would‐be suprachiasmatic region of the third ventricle. In 70% of the animals examined histologically during the latter phase of development and as adults, regulation occurred and the brains were largely comparable with those of controls. However, in the remaining mutant mice, the overall size of either, or sometimes both, SCN was much reduced. The basal (but not the apical) dendrited of SCN neurons failed to develop fully. Some basal dendrites normally invade the optic chiasm below. In several mutant animals one or the other SCN had greatly increased numbers of cells, while the contralateral one had diminished numbers. These observations suggest that regular formation of the suprachiasmatic region of the hypothalamus and especially the suprachiasmatic nuclei, may depend during development upon the presence of the eye or the subjacent opti

ISSN:0092-7317    

DOI:10.1002/cne.901760409

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

年代:1977

数据来源: WILEY

摘要:

Abstract3H estradiol–17β was localized in nuclei of catecholamine (CA) neurons of the rat lower brain stem, i.e., midbrain, pons and medulla, by employing a combined formaldehyde‐induced fluorescence (FIF)‐autoradiography approach which permits the direct visualization of3H estradiol uptake in relation to CA‐neuron perikarya and terminals. In the medulla, noradrenalin (NA)‐containing neurons in and adjacent to the nucleus (n.) reticularis lateralis (group A1) and in the vicinity of the n. tractus solitarii (group A2) concentrated3H estradiol. In the pons, NA neurons dorsal to the n. olivaris superior (group A5), in the locus ceruleus (group A6) and ventral to the pedunculus cerebellaris superior (group A7) displayed3H estradiol uptake. In the midbrain, dopamine (DA)‐containing neurons in the n. cuneiformis (group A8), in the zona compacta of the substantia nigra (group A9) and adjacent to the n. interpeduncularis (group A10), were not seen to concentrate3H estradiol. This is in contrast to DA neurons in the n. arcuatus of the hypothalamus (group A12), previously reported to concentrate3H estradiol. In addition, certain non‐CA‐containing neurons with nuclear uptake of3H estradiol were observed to be surrounded by CA terminals in such areas as substantia grisea centralis, n. tractus solitarii and n. tractus spinalis nervi trigemini. This suggests a second mode of interaction between CA neurons and estrogen target neurons. The estradiol‐CA neuron relationships described may provide morphological substrates underlying functional interactions between estradiol and CA neuron

ISSN:0092-7317    

DOI:10.1002/cne.901760410

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

年代:1977

数据来源: WILEY

摘要:

AbstractThe descending connections of the mammillary nuclei of the rat were studied using the autoradiographic technique to trace anterograde axonal connections. Injections of tritiated leucine or tritiated proline were stereotaxically aimed at either the medial or lateral mammillary nucleus. Label in the medial and lateral mammillary nuclei was rated as either high or low. With a rating of high in both medial and lateral mammillary nuclei (11 animals) three major projection sites were seen: the dorsal tegmental nucleus (DTN), the ventral tegmental nucleus (VTN) and a pontine region which included both the pontine grey and the tegmental reticular nucleus. In the nine animals in which the medial mammillary nucleus was rated high but the lateral mammillary nucleus was rated low, no label was present in DTN, although the other two regions were labeled. The one animal in which the lateral mammillary nucleus was high but the medial was low, had label in all three major projection sites; since fibers destined for the DTN pass through the VTN, it could not be determined whether or not lateral mammillary efferents were in synaptic contact with the VTN. Labeled fibers were present throughout a wide dorsal‐ventral extent of the mesencephalon; these fibers are components of the mammillotegmental system and not part of the mammillary peduncl

ISSN:0092-7317    

DOI:10.1002/cne.901760411

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

年代:1977

数据来源: WILEY