摘要:

AbstractA projection from large pyramidal cells in layer V of the rat somatic sensory‐motor (SSM) cortex both to the neostriatum and the brainstem was demonstrated by intracellular recording and injection of horseradish peroxidase (HRP). Layer V neurons that project to the brainstem were identified either by antidromic activation from the cerebral peduncle or by tracing the HRP‐labeled axon into the internal capsule in histochemically processed sections. Intracellular responses to stimulation of the hindlimb, forelimb or mystacial pad were also examined.Five of 20 HRP‐injected neurons that project to the brainstem had a fine collateral branch within the striatum. These branched corticostriatal cells respond at short latency (7–12 msec) to somatic sensory stimulation. All of the injected corticofugal neurons that had a striatal collateral were large pyramidal neurons located in layer Vb of the forelimb and head areas of SSM cortex.Branched corticofugal neurons have a rich basal dendritic field and a prominent apical dendrite that arborizes in the superficial cortical layers. Intracortical axon collaterals from the branched cells ramify in layers V and VI, and also project to the upper layers of cortex, near the apical dendrite. Beyond the cortex, the main axon has no collateral branches, except for a single laterally directed branch in the neostriatum. The diameter of the striatal collateral is small (about 0.5 μm), compared to that of the main axon (2.0–2.5 μm). It is concluded that these branched cells provide a parallel input to the neostriatum and to brainstem or spinal mo

ISSN:0092-7317    

DOI:10.1002/cne.902010102

出版商:Alan R. Liss, Inc.    

年代:1981

数据来源: WILEY

摘要:

AbstractThe unlabeled peroxidase‐anti‐peroxidase method was used to stain glial fibrillary acidic (GFA) protein in the optic nerve of the developing albino rat. Optic nerves from animals ranging in age from the day of birth to adulthood were embedded in paraffin following fixation with various agents for times ranging from 30 minutes to 48 hours. GFA protein activity was demonstrable at birth in large astrocytic processes following fixation with alcohols or with Perfix for short intervals, but not with 4% or 2% buffered paraformaldehyde solutions. With increasing age, GFA protein could be demonstrated using higher aldehyde concentrations, longer fixation times, and longer paraffin embedding schedules. At all ages GFA protein activity was greater following treatment with nonaldehyde fixatives rather than those containing formaldehyde or glutaraldehyde. At birth the majority of GFA protein‐containing processes were confined to planes which were perpendicular to the axons of the optic nerve. With increasing age, tangential and longitudinal processes became more numerous until, in the mature optic nerve, astrocytic processes were best characterized as being multidirect

ISSN:0092-7317    

DOI:10.1002/cne.902010103

出版商:Alan R. Liss, Inc.    

年代:1981

数据来源: WILEY

摘要:

AbstractThe connections of the inferior colliculus, the mammalian midbrain auditory center, were determined in the greater horseshoe bat (Rhinolophus ferrumequinum), using the horseradish peroxidase method. In order to localize the auditory centers of this bat, brains were investigated with the aid of cell and fiber‐stained material.The results show that most auditory centers are highly developed in this echolocating bat. However, the organization of the central auditory system does not generally differ from the mammalian scheme. This holds also for the organization of the superior olivary complex where a well‐developed medial superior olivary nucleus was found. In addition to the ventral and dorsal nuclei of the lateral lemniscus a third well‐developed nucleus has been defined which projects ipsilaterally to the inferior colliculus and which was called the intermediate nucleus of the lateral leminiscus.All nuclei of the central auditory pathway project ipsi‐, contra‐, or bilaterally to the central nucleus of the inferior colliculus with the exception of the medial nucleus of the trapezoid body and the medial geniculate body. The tonotopic organization of these projections and their possible functions are discussed in context with neurophysiological inves

ISSN:0092-7317    

DOI:10.1002/cne.902010104

出版商:Alan R. Liss, Inc.    

年代:1981

数据来源: WILEY

摘要:

AbstractThe efferent connections of the olfactory bulb (OB) in the opossum (Didelphis marsupialis aurita) were studied by the aid of the Fink‐Heimer technique.Following lesions restricted to the OB, ipsilateral degenerating fibers entered the lateral olfactory tract and were traced to terminal fields essentially limited to the outer portion of the plexiform layer (sublamina IA) of the following structures: all the subdivisions of the anterior olfactory nucleus, the rostroventral tenia tecta, the full extent of the olfactory tubercle, the nucleus of the lateral olfactory tract, the anterior portion of the medial amygdaloid nucleus, the whole cortical amygdaloid nucleus (in the posteromedial subdivision of this structure the degeneration was very scanty), and the sulcal, piriform, and lateral entorhinal cortices. Some degree of topographical organization in the OB projections was noticed in the rostral portion of the lateral olfactory tract and within the external and lateral subdivisions of the anterior olfactory nucleus.In another series of experiments, when the lesion also involved the accessory olfactory bulb, heavy terminal degeneration occurred along the whole extent of the medial amygdaloid nucleus and in the posteromedial subdivision of the cortical amygdaloid nucleus.These findings indicate that, although very similar to those described in other mammals, the OB efferent connections in the opossum present some peculiarities; namely, the existence of dense terminal fields in the sulcal cortex and in the rostral district of the medial amygdaloid nucleu

ISSN:0092-7317    

DOI:10.1002/cne.902010105

出版商:Alan R. Liss, Inc.    

年代:1981

数据来源: WILEY

摘要:

AbstractThe comparative distribution of nine peptides was examined in the L4 segment of the rat cord using the peroxidase antiperoxidase technique. The peptides examined were substance P, neurotensin, cholecystokinin, methionine‐enkephalin, oxytocin, neurophysin, adrenocorticotrophin, thyrotropin releasing hormone, and vasoactive intestinal polypeptide. No transport blocking agents were used and in spite of this cell bodies containing substance P, neurotensin, cholecystokinin, and methionine‐enkephalin were observed. All peptides except for thyrotropin releasing hormone were observed in fibers in laminae I and II. All peptides were present in the area around the central canal, laminaX. Each peptide had its own characteristic distribution within fibers in the gray and white mat

ISSN:0092-7317    

DOI:10.1002/cne.902010106

出版商:Alan R. Liss, Inc.    

年代:1981

数据来源: WILEY

摘要:

AbstractThe enzyme horseradish peroxidase (HRP) was separately injected into striate, prestriate, inferotemporal, and parietal cortices in 19 macaque monkeys, and the lateral geniculate nucleus (LGN) was examined for retrograde transport. Labeled LGN cells were identified only in the animals with HRP injections into the striate and prestriate cortex. Following injections into either of these regions, labeled cells were found in both parvocellular and magnocellular regions of the ipsilateral LGN only, in keeping with the topographic relation of HRP injection sites in the cortex to labeled areas in the LGN. It was also found that (1) labeled LGN cells were less numerous in both laminar and interlaminar zones following HRP injection into the prestriate cortex, whereas following HRP injection into the striate cortex labeled cells were found almost exclusively in the laminae, and localized to a wedge‐shaped region; (2) following HRP injection into the prestriate cortex, the mean sizes of the labeled parvocellular and magnocellular cells, estimated in projected diameter, were almost the same, these means being significantly larger than the mean size of labeled parvocellular cells and much smaller than that of labeled magnocellular cells following HRP injection into the striate cortex; (3) the shapes of the labeled LGN cells following HRP injection into the prestriate cortex were ovoid, fusiform, or triangular (or multipolar), whereas those following HRP injection into the striate cortex were uniformly ovoid or round. The above findings following HRP injections into the prestriate cortex in normal monkeys were confirmed by HRP injections into the prestriate cortex of monkeys whose striate cortex had been removed several months prior to the injection; labeled cells were found in the confines of areas of retrograde degeneration in the LGN and their labeling pattern was the same as that in intact animals. It was concluded that in macaque monkeys, just as in the cat, a geniculoprestriate projection system exists; it was suggested that there are two parallel systems of visual information processing from the LGN to the prestriate cortex, a direct one and an indirect one through the striate corte

ISSN:0092-7317    

DOI:10.1002/cne.902010107

出版商:Alan R. Liss, Inc.    

年代:1981

数据来源: WILEY

摘要:

AbstractFollowing a series of lesions in dorsal (DPML) and ventral (VPML) divisions of tree shrew (Tupaia) paramedian lobule (PML), the distribution of degenerated axons within the deep cerebellar nuclei was determined using the Fink and Heimer ('67) method. Damage to PML produced axonal degeneration in lateral (NL), anterior interposed (NIA), and posterior interposed (NIP) cerebellar nuclei. No degenerated fibers could be traced to either the medial cerebellar nucleus or vestibular complex, via juxtarestiform body, from lesions in PML. Corticonuclear fibers to NL, NIA, and NIP from PML cortex are topographically organized. Subsequent to lesions of lateral DPML, axonal debris is found in rostral and medial NL, while the lateral edge of VPML projects primarily into medial NL. According to the terminology of Voogd ('69) these lateral regions of PML represent the D zone. The NIP receives corticonuclear input from a relatively wide middle area of both portions of PML, interpreted as the C2zone. There is some evidence which suggests that medial portions of the C2area of DPML project into more lateral areas of NIP, while lateral regions of this zone in DPML are related to more medial NIP. This projection pattern is inverted for the C2area of VPML; medial C2to medial NIP, lateral C2to lateral NIP. Corticonuclear fibers of PML which enter NIA appear to arise from a narrow, irregular, partially discontinuous strip of cortex located at the interface of the D and C2areas in lateral PML and from a wider, more regular region in the most medial areas of this lobule. These represent, respectively, the C3and C1zones.Although an overall pattern of zones is present, there is evidence to suggest that their spatial organization differs from DPML to VPML. The zonal pattern appears to be more obvious in VPML, while this pattern for DPML is less distinct. This is interpreted as indicating that either (1) zones C1−C3overlap to a greater degree in DPML than in VPML, or (2) zones C1and C3may converge in rostral DPML, partially obliterating the intervening zone C2. The different ways in which zonal terminology is applied to both corticonuclear and certain of the afferent cerebellar systems are discusse

ISSN:0092-7317    

DOI:10.1002/cne.902010108

出版商:Alan R. Liss, Inc.    

年代:1981

数据来源: WILEY

摘要:

AbstractMicroelectrode multiunit recording methods were used to determine the somatotopic organization of the second somatosensory area, S‐II, in tree shrews. Neurons were activated by light tactile stimuli, and receptive fields were located on the contralateral body surface only. The orientation of S‐II was such that the top of the head adjoined S‐I and the distal limbs pointed away from S‐I so that the representation could be characterized as “erect.” In general, the distortions of the body surface in S‐II were similar to those found in S‐I of the tree shrew (Sur et al., '80), with the exception that proportionately less cortex was devoted to the glabrous nose. The representation in S‐II was more continuous than that in S‐I. Finally, cortex bordering S‐II caudally was found to be responsive to generally more intense somatosensory stimuli such as tap

ISSN:0092-7317    

DOI:10.1002/cne.902010109

出版商:Alan R. Liss, Inc.    

年代:1981

数据来源: WILEY

摘要:

AbstractMicroelectrode mapping methods revealed that the representation of the body surface in the first somatosensory area of cortex, S‐I, of the tree shrew is unique in that only the ventral trunk was found in the usual location of the trunk representation in cortex of the dorsolateral surface of the cerebral hemisphere. Instead, the dorsal trunk was found as an extension of the representation of the posterior leg in cortex on the medial wall. The separation of the representation of the trunk occurs along a line that is counter to the orientation of the dorsal root dermatomes, so that S‐I of the tree shrew clearly cannot be characterized as a serial representation of dermatomes. Anatomical studies of connections support the conclusion that the representation of the trunk is split in S‐I. Both the representation of the dorsal trunk on the medial wall of the cerebral hemisphere and S‐I of the dorsolateral surface were found to project to S‐II when horseradish peroxidase was injected

ISSN:0092-7317    

DOI:10.1002/cne.902010110

出版商:Alan R. Liss, Inc.    

年代:1981

数据来源: WILEY

ISSN:0092-7317    

DOI:10.1002/cne.902010111

出版商:Alan R. Liss, Inc.    

年代:1981

数据来源: WILEY