摘要:

AbstractFollowing large and small lesions (in many cases bilateral) of the proreate gyrus in adult cats the ensuing degeneration in the pontine nuclei was studied with the silver impregnation methods of Nauta and of Fink and Heimer. Lesions were produced by transdural thermocoagulationThe main results are as follows:1All parts of the proreate gyrus on the convexity of the hemisphere emit fibers to the pontine nuclei. The projection from the dorsal part is somewhat less intense than that from the ventral part. The density of projection from the proreate gyrus is far less than from the anterior sigmoid gyrus (motor cortex).2The proreate gyrus projects upon two longitudinal columns in the ipsilateral pontine gray. One column is located medially, the other laterally.3The exact localization of these columns has been compared with the localization of the columns projected upon by the anterior sigmoid gyrus. No clear difference has been found.4No topical localization could be demonstrated within the pontine projection from the proreate gyrus, which in this respect differs from the projection from the anterior sigmoid gyrus (motor cortex), which projects somatotopically upon both columns. Possible relations between the proreate gyrus and the cerebellum are discussed.

ISSN:0092-7317    

DOI:10.1002/cne.901420202

出版商:The Wistar Institute of Anatomy and Biology    

年代:1971

数据来源: WILEY

摘要:

AbstractFollowing large and small lesions of the orbital gyrus in adult cats the ensuing degeneration in the pontine nuclei was studied with the silver impregnation methods of Nauta and of Fink and Heimer. Lesions were produced by transdural thermocoagulation. The main results are as follows:1All parts of the orbital gyrus give off fibers to the pontine nuclei. The density of projection is less than from the anterior ectosylvian gyrus (second somatosensory area).2The orbital gyrus projects upon four longitudinal columns within the pontine nuclei. One is located medially, one ventromedially, one ventrolaterally and one dorsolaterally.3The exact localization of these columns has been compared with the localization of the columns projected upon by the anterior ectosylvian gyrus. Three of the columns (the medial, ventrolateral and dorsolateral) appear to be projected upon by both gyri, while the fourth one receives afferents from the orbital gyrus only.4A topical localization exists within the projection from the orbital gyrus insofar as the anterior part of the gyrus projects onto the medial, ventrolateral and dorsolateral columns, while the posterior part projects onto the ventromedial column mainly.Whether a somatotopical localization is present within the projection to some or all of the columns can not be decided from the material.

ISSN:0092-7317    

DOI:10.1002/cne.901420203

出版商:The Wistar Institute of Anatomy and Biology    

年代:1971

数据来源: WILEY

摘要:

AbstractThe rapid Golgi method was used to classify the neurons in the MES and PES auditory areas of the dog. Small pyramids were found in layer II with percentages of 12% in the MES area and 8.1% in the PES area. Medium sized pyramids possessed a bimodal distribution, the first in layer IV and the second in V, with 58% in MES and 62% in PES. Large pyramids were found in layer V with a proportion of 12.5% in MES and 17% in PES. The star neurons were found in layer III with proportions of 5.9% in MES and 4.0% in PES. The double bouquet neurons in layer III had a proportion of 1.5% in MES and 1.7% in PES. Fusiform neurons in layers V and VI were in proportions of 2.2% in MES and 6.4% in PES. The principal finding was a special auditory cell occurring in layers V and VI of the MES area with a proportion of 8% and from 14.8 to 34.8% in the strata between 1 and 2 mm. Less than 1% of neurons in the PES area were identified as special cells. Its appearance was an inverted pyramidal cell with a large dendrite extending toward the white matter from which the axon arose.

ISSN:0092-7317    

DOI:10.1002/cne.901420204

出版商:The Wistar Institute of Anatomy and Biology    

年代:1971

数据来源: WILEY

摘要:

AbstractOrganotypic explants of neonatal mouse cerebellum were cultured for periods up to 56 daysin vitro. Living cultures were compared to those fixed and stained by the Holmes' reduced silver nitrate method. The explants consist of a heterologous neuronal population comparable to that foundin situ. Since the differentiation of the cerebellum is actively in progress during the neonatal and postnatal periods, cultures derived from such tissue demonstrate the developmental phases that are present at the time of explantation.Thein vitro. maintenance of neonatal mouse cerebellum allows the expression of those aspects of neuronal development which are intrinsic to the cell proper and primarily concerned with type‐specific differentiation, e.g., neurofibrillary development; axonal growth; myelination; and the acquiring of basic dendritic patterns. The secondary aspects of differentiation, which determine the adult state and which are characterized primarily by the increasing complexity of dendritic formation and of synaptic interactions, occur to a much lesser extentin vitro.The importance of recognizing transitional forms as normal and not peculiar to thein vitrosituation is emphasize

ISSN:0092-7317    

DOI:10.1002/cne.901420205

出版商:The Wistar Institute of Anatomy and Biology    

年代:1971

数据来源: WILEY

摘要:

AbstractMyelinated fibers are described in teleost (carp, goldfish) and elasmobranch (dogfish) retinas which make synapses onto amacrine cell bodies and bipolar cell terminals. The fibers run in parallel with bundles of optic nerve fibers radiating from the optic disk until at some point they traverse the inner plexiform layer, turning again horizontally to course under the layer of amacrine cell bodies for 0.5–0.75 mm.En routeeach fiber makes severalen passantsynapses characterized by a cessation of the myelin sheath, a local increase in axonal diameter, an accumulation of agranular vesicles 300–400 Å in diameter and increased densification of pre‐ and post‐synaptic membranes. These fibers are not post‐synaptic to any retinal element. The evidence that the myelinated fibers described form an efferent system is based on their resemblance in many particulars to the centrifugal fiber system innervating the pigeon retina. Degeneration experiments, however, could not distinguish conclusively between a true efferent system, originating in some central nucleus, and a recurrent collateral system branching from afferent optic n

ISSN:0092-7317    

DOI:10.1002/cne.901420206

出版商:The Wistar Institute of Anatomy and Biology    

年代:1971

数据来源: WILEY

摘要:

AbstractThe time‐course of disintegration of neurons, and the concomitant reactions of various types of glial cells, in the dorsal nucleus of the lateral geniculate body (LG) were studied in 12 Rhesus monkeys sacrificed in groups of two at time intervals of 1, 3, 6, 12, 25 and 50 weeks following unilateral removal of the occipital lobe. The change in the mean number of neurons, astrocytes, oligodendrocytes and microglia, found per unit of volume, in Nissl preparations, of the degenerated LG, was expressed as a percentage of the mean number of the corresponding cells estimated in the normal LG on the same slide. The number of degenerating neurons decreased progressively. While 12 weeks following surgery a few isolated nerve cell nuclei could still be seen in the LG, by the end of the twenty‐fifth postoperative week the nucleus was practically devoid of neurons. The reaction of the astrocytes indicated a biphasic process—proliferation with subsequent reversal to an almost normal level. The oligodendrocytes and microglia multiplied at a somewhat slower rate, but remained far above the control values over a period of 50 postoperative

ISSN:0092-7317    

DOI:10.1002/cne.901420207

出版商:The Wistar Institute of Anatomy and Biology    

年代:1971

数据来源: WILEY

摘要:

AbstractThalamic responses to somatic stimulation were studied in 47 specimens of the South American opossum, D.marsupialis aurita. Topographic representation of the body surface in the ventrobasal complex was determined by recording unit cluster responses to natural stimulation in sodium pentobarbital anesthetised animals. The pattern of representation observed was similar to that reported in the North American subspecies and comparable to the findings in eutherian mammals.The analysis of single units recorded with extra‐cellular microelectrodes showed that the great majority of neurons are place and modality specific. A predominance of skin (vs. deep) sensibility was observed. Units activated by displacement of hairs and vibrissae displayed receptive fields similar to those reported in higher mammals. Of the units isolated within the anatomical boundaries of the ventrobasal complex only 1% showed wide receptive fields, or bilateral representation. None of the units could be activated by auditory stimulation. Neurons displaying wide, discontinuous or bilateral receptive fields showing auditory‐somatic convergence were isolated in nucleus parafascicularis, subparafascicularis and in the Posterior gr

ISSN:0092-7317    

DOI:10.1002/cne.901420208

出版商:The Wistar Institute of Anatomy and Biology    

年代:1971

数据来源: WILEY

摘要:

AbstractSerial sections of the brains of four adult male hyraxes revealed a hitherto undescribed ependymal organ near the middle of the midbrain aqueduct. This structural modification of the dorsal wall of the aqueduct is separate and different from both the subcommissural organ and the posterior collicular recess. It is characterized by: (1) an elaborate system of ridges and crypts, (2) numerous, crowded and distinctive ependymocytes, (3) tissue zonation, and (4) numerous vessels with sleeves of primarily longitudinally arranged glial processes. Comparisons with other ventricular organs and possible functional relations are discussed.

ISSN:0092-7317    

DOI:10.1002/cne.901420209

出版商:The Wistar Institute of Anatomy and Biology    

年代:1971

数据来源: WILEY

ISSN:0092-7317    

DOI:10.1002/cne.901420201

出版商:The Wistar Institute of Anatomy and Biology    

年代:1971

数据来源: WILEY