摘要:

AbstractExtrinsic and intrinsic fiber connections of the telencephalic subdivisions of Nieuwenhuys (1962) in a teleost,Sebastiscus marmoratus, were studied by means of horseradish peroxidase (HRP) and Fink‐Heimer methodsThe olfactory bulb projects bilaterally to area dorsalis pars posterior, area ventralis pars ventralis, pars lateralis, pars posterior, pars intermedia, and the nucleus posterior tuberis of Peter et al. (1975) and receives fibers from ipsilateral area dorsalis pars centralis, pars posterior, area ventralis pars dorsalis, and pars supracommissuralis. Area dorsalis pars posterior sends numerous fibers to the ipsilateral ventral region of area dorsalis pars medialis, from which fibers of the medial forebrain bundle arise and terminate in the inferior lobe and nucleus posterior tuberisArea dorsalis pars lateralis, pars dorsalis, and the dorsal region of pars medialis are the main targets of extratelencephalic ascending afferents. Area dorsalis pars lateralis receives fibers from the ipsilateral nucleus pre‐thalamicus of Meacler (1934), where tectal projections terminate massively. Area dorsalis pars dorsalis and the dorsal region of pars medialis receive afferents from the ipsilateral nucleus prcglomerulosus of Schnitzlein (1962), nucleus posterior tuberis, area preoptica pars medialis of Crosby and Showers (1969), and nucleus entopeduncularis of Sheldon (1912). Raphe nuclei and locus ceruleus project bilaterally to area dorsalis pars centralis, pars dorsalis, pars lateralis, and the dorsal region of pars medialis. Area dorsalis pars centralis, pars dorsalis, and the dorsal region of pars medialis are important sources of extrateiencephalic efferents. These subdivisions give rise to the lateral forebrain bundle and project to the ipsilateral nucleus prethalamicus, nucleus pregiomerulosus, inferior lobe, nucleus paracommissuralis of Ito et al. (1982), optic tectum, torus semicircularis, and the bilateral mesencephalic tegmentumWithin the telencephalon, most of the ventral subdivisions project to ipsilateral area dorsalis pars centralis, pars dorsalis, pars lateralis, and the dorsal region of pars medialis. Area dorsalis pars centralis has reciprocal connections with ipsilateral area dorsalis pars lateralis, pars dorsalis, pars posterior, and the dorsal region of pars medialis. A dorsal part of the anterior commissure is composed of axons of the ventral region of area dorsalis pars medialis destined to the contralateral ventral region of area dorsalis pars medialis. A ventral part of the anterior commissure contains axons of area dorsalis pars centralis destined to contralateral area dorsalis pars latera

ISSN:0092-7317    

DOI:10.1002/cne.902160202

出版商:Alan R. Liss, Inc.    

年代:1983

数据来源: WILEY

摘要:

AbstractIn the light of hypotheses related to the evolution of pain‐carrying systems in mammals, terminal projection fields in brainstem and diencephalon of efferents of nucleus caudalis (NC) of the spinal trigeminal complex and spinal cord were determined in hedgehog by using Nauta‐Gygax and Fink‐Heimer silver techniques for degeneration.Unilateral NC lesions resulted in medullary degeneration in the ventral portion of NC contral a ter ally and bilaterally in cuneate nucleus (CU) and reticular formation. Pontine degeneration was noted ipsilaterally in medial (PBM) and lateral (PBL) parabrachial, facial motor (VII), and interpolar, oral, and main sensory trigeminal nuclei; degeneration in reticular formation was bilateral. Midbrain degeneration was seen bilaterally in caudal superior colliculus (SO), inferior colliculus (IC), periaqueductal gray, and tegmentum. In thalamus, projections to ventroposterior nucleus (VP) were contralateral and concentrated in a crescent extending along the lateral one‐third‐to‐one‐halfand ventral border of the nucleus. Bilateral degeneration fields were noted in a dorsomedial sector of the “ventral nuclear field,” posterior complex (PO), and mediodorsal nucleus (MD), the degeneration always heavier contralaterally in these nuclei. Sparse degeneration was noted in the medialmost portions of the medial geniculate nuclei bordering PO and VP. In rostral diencephalon, bilateral degeneration was traced from the inferior thalamic peduncle to the lateral hypothalamic area (LH).Unilateral spinal cord lesions made between C7 and Tl vertebrae resulted in medullary degeneration in NC contralaterally, ipsilaterally in CU and lateral cuneate nucleus, and bilaterally in gracile nucleus, inferior olivary complex, and reticular formation. Pontine degeneration was limited to ipsilateral PBL and bilaterally to VII. Midbrain degeneration was found bilaterally in IC, SC, nucleus sagulum, and tegmentum; a minor projection was noted in interpeduncular nucleus. In thalamus, projections were confined to ipsilateral PO and zona incerta. In rostral diencephalon bilateral fields were noted in LH.NC terminations in PO and VP parallel results of research in hedgehogs on thalamic projections of the dorsal column nuclei (Jane and Schroeder, 1971), and particularly the location in VP of most cells responsive to stimulation of the face (Erickson et al., 1967). This suggests that somatic input from NC, some of which may be pain‐specific, reaches thalamic areas, a portion of whose neurons are characterized as polymodal and at least partially convergent for somatotopy. These results are consistent with the thesis that specific sensothalamic nuclei evolved from a diffuse sensory region. Response properties of neurons in the dorsomedial portion of the ventral nuclear field, an area which also received NC efferents, are not known. Last, NC projections to MD and LH implicate the role of “limbic”

ISSN:0092-7317    

DOI:10.1002/cne.902160203

出版商:Alan R. Liss, Inc.    

年代:1983

数据来源: WILEY

摘要:

AbstractThe transition from aquatic to terrestrial hearing in the frog occurs during metamorphosis and during the disappearance of the lateral line system. The coincidence in time of these two processes and morphological similarities between the acoustic and lateral line systems has led to the suggestion (Larsell, 1934) that the lateral line nuclei are transformed into the acoustic nuclei. The relation between the acoustic and lateral line systems was investigated by studying the distribution of primary afferents, the dendritic patterns of the cells in the primary nuclei, and the development of the nuclei in the premetamorphic bullfrog,Rana catesbeianaThe posterior and anterior lateral line roots distribute to a neuropil located medial to the dorsal medullary nucleus. Horseradish peroxidase (HRP) injections into the contralateral tegmentum fill cells in the periventricular region whose dendrites ramify within the neuropil. These cells constitute the lateral line nuclei. The amphibian and basilar papillary roots of the acoustic system distribute to the more lateral nuclear region. The dendrites of these cells arborize within the nucleus and not in the lateral line neuropil. The dorsal medullary nucleus is, therefore, the acoustic nucleus (AcN). [3H]‐thymidine labeling reveals that newly generated cells occupy the AcN within a few hours of their formation throughout the period when anatomical analysis shows the parallel growth and diminution of the lateral line neuropil and nucleiThis study indicates that the lateral line and acoustic systems are morphologically independent at the level of the primary afferents and primary nuclei throughout early developmen

ISSN:0092-7317    

DOI:10.1002/cne.902160204

出版商:Alan R. Liss, Inc.    

年代:1983

数据来源: WILEY

摘要:

AbstractThe segmental and central distributions of renal nerve afferents in adult cats and kittens were studied by using retrograde and transganglionic transport of horseradish peroxidase (HRP). Transport of HRP from the central cut ends of the left renal nerves labeled afferent axons in the ipsilateral minor splanchnic nerves and sensory perikarya in the dorsal root ganglia from T12 to L4. The majority of labeled cells (85%) were located between L1 and L3. A few neurons in the contralateral dorsal root ganglia were also labeled. Labeled cells were not confined to any particular region within a dorsal root ganglion. Some examples of bifurcation of the peripheral and central processes within the ganglion were noted. A small number of preganglionic neurons, concentrated in the intermediolateral nucleus, were also identified in some experiments. In addition, many sympathetic postganglionic neurons were labeled in the renal nerve ganglia, the superior mesenteric ganglion, and the ipsilateral paravertebral ganglia from T12 to L3Transganglionic transport of HRP labeled renal afferent projections to the spinal cord of kittens from T1 1 to L6, with the greatest concentrations between Ll and L3. These afferents extended rostrocaudally in Lissauer's tract and sent collaterals into lamina I. In the transverse plane, a major lateral projection and a minor medial projection were observed along the outer and inner margins of the dorsal horn, respectively. From the lateral projection many fibers extended medially in laminae V and VI forming dorsal and ventral bundles around Clarke's nucleus. The dorsal bundle was joined by collaterals from the medial afferent projection and crossed to the contralateral side. The ventral bundle extended into lamina VII along the lateroventral border of Clarke's nucleus. Some afferents in the lateral projection could be followed ventrally into the dorsolateral portion of lamina VII in the vicinity of the intermediolateral nucleus. In the contralateral spinal cord, labeled afferent fibers were mainly seen in laminae V and VIThese results provide the first anatomical evidence for sites of central termination of renal afferent axons. Renal inputs to regions (laminae I, V, and VI) containing spinoreticular and spinothajamic tract neurons may be important in the mediation of supraspinal cardiovascular reflexes as well as in the transmission of activity from nociceptors in the kidney. In addition, the identification of a bilateral renal afferent projection in close proximity to the thoracolumbar autonomic nuclei is consistent with the demonstration in physiological experiments of a spinal pathway for the renorenal sympathetic reflexes.

ISSN:0092-7317    

DOI:10.1002/cne.902160205

出版商:Alan R. Liss, Inc.    

年代:1983

数据来源: WILEY

摘要:

AbstractNucleus rotundus, a tectorecipient thalamic nucleus in reptiles and birds, is described for the first time in a snake. The morphology of rotunda neurons and tectorotundal axons was studied at the light microscopic level by using anterograde and retrograde filling with horseradish peroxidase (HRP)Injections of HRP in the dorsal ventricular ridge retrogradely fill neurons in rotundus. Rotundus is situated centrally in the caudal diencephalon medial to the cell plate of the retinorecipient geniculate complex and ventrolateral to the lentiform thalamic nucleus. The dendrites of rotundal neurons are long and radiate, but are confined within the cytoarchitectonically defined borders of the nucleus. Injections of HRP into the optic tectum anterogradely fill axons that project to rotundus bilaterally via the tectothalamic tract. Small injections show that axons arising from a single tectal locus distribute to all sectors of rotundus. Thus, this projection may not be retinotopically organized. However, single axons reconstructed through serial sections form spatially restricted, sheetlike terminal fields that pass caudorostrally through the entire extent of rotundus.Several hypotheses on the functional significance of such organized but nonretinotopic visual projections are discussed.

ISSN:0092-7317    

DOI:10.1002/cne.902160206

出版商:Alan R. Liss, Inc.    

年代:1983

数据来源: WILEY

摘要:

AbstractThe connections of rat cingulate cortex with visual, motor, and postsubicular cortices were investigated with retrograde and anterograde tracing techniques. In addition, connections between visual and the postsubicular (area 48) and parasubicular (area 49) cortices were evaluated with the same techniques. The following conclusions were drawnArea 29 connections: Afferents to area 29 originate mainly from cingulate areas 24 and 25, visual cortex (primarily area 18b), motor cortex area 8, area 11 of frontal cortex, areas 48 and 49, and the subiculum. Efferent connections of area 29 within cingulate cortex and to visual areas differ for each cytoarchitectural subdivision of area 29. Thus, area 29c has limited projections both within cingulate cortex and to areas 48 and 49, while area 29d projects to these areas as well as to area 8, area 18b, and medial area 17. These visual cortex afferents originate mainly from layer V neurons of areas 29b and 29d, while areas 29a and 29c have virtually no projections to visual cortexArea 24 connections: Afferents to area 24 originate primarily from cingulate areas 25 and 29 and visual area 18b and medial area 17. Efferent projections of area 24a are distributed within cingulate cortex, while area 24b has more extensive projections to posterior cingulate and visual cortices. Area 24b is the cingulate subdivision which is both the primary recipient of visual cortex afferents as well as the source of most of the projections of anterior cingulate cortex to visual areasVisual cortex has reciprocal connections with parts of the postsubicular and parasubicular cortices. Neurons of the internal pyramidal cell layer of both areas 48 and 49 project to areas 17 and 18b, while layers I and III of these parahippocampal areas receive projections from areas 17 and 18bIn conclusion, areas 29d and 24b have particularly extensive interconnections with visual cortex, while area 29d also maintains projections to area 8 of motor cortex. This connection scheme supports the view that cingulate cortex may have a role in feature extraction from the sensory environment, as well as in sensorimotor integration. Finally, the postsubiculum may be classified as alimbic association cortex in which extensive visual and cingulate efferents converge.

ISSN:0092-7317    

DOI:10.1002/cne.902160207

出版商:Alan R. Liss, Inc.    

年代:1983

数据来源: WILEY

摘要:

AbstractThe distribution, morphology, size, and number of cells in the retinal ganglion layer of the marsupialSetonix brachyurus, “quokka,” was studied from 25 days postnatal to adulthood using Nissl‐stained wholemountsThetotal cell populationwas evenly distributed up to 50 days, but by 75 days highest densities were generally observed in a broad band extending across the nasotemporal axis. At 87 days, a temporally situated area centralis was seen for the first time. This was embedded in a horizontally aligned visual streak, the nasal arm of which contained areas of high density. By 106 days, densities in the area centralis had stabilized while peripheral values were higher than adult levels even at 180 days. In the adult, the area centralis was surrounded by a weak visual streak Retinal area increased steadily during development to reach 168 mm2180 days, the adult range being 225–250 mm2All cells in the ganglion layer appeared undifferentiated and rounded at 33 days with soma diameters of 3‐6 μm; by 70 days diameters had increased to 4‐12 μm and some cells had axon hillocks containing Nissl substance. From 87 days we distinguished ganglion cells, which constituted 54‐63% of the total. These were identified by deeply stained Nissl substance and had diameters of 7‐18 μm, compared to 7–23 μm at 143 days and 7‐24 μm in the adult; the remaining cells, termed glia/interneurons, were 5–8 μm throughout. Only ganglion cells were organized into an area centralis and visual streak. Glia/interneurons were evenly distributed except at the extreme periphery, where their density increased. In sectioned material, the ganglion layer was distinct from 25 days while the neuroblastic layer separated only between 48 and 85 daysFrom 25 to 250 days the total number of cells in the ganglion layer remained similar to the adult range of 336, 000‐393, 000. At both 87 days and in adults optic axon counts fell between 180, 000 and 224, 000, close to ganglion cell estimates. At 25 and 34 days, respectively, optic axon numbers were 75, 000 and 172, 000. Myelination was absent at 25 and 34 days, 3% at 87 days, and almost 100% in adultsMechanisms are discussed whereby the area centralis and visual streak may evolve from an even distribution of cells while their number remains constant; migration is cons

ISSN:0092-7317    

DOI:10.1002/cne.902160208

出版商:Alan R. Liss, Inc.    

年代:1983

数据来源: WILEY

ISSN:0092-7317    

DOI:10.1002/cne.902160201

出版商:Alan R. Liss, Inc.    

年代:1983

数据来源: WILEY