摘要:

AbstractAntisera against the crustacean pigment‐dispersing hormone (β‐PDH) were used in immunocytochemical preparations to investigate the anatomy of PDH‐immunoreactive neurons in the nervous system of wild‐typeDrosophila melanogasterand in that of several brain mutants of this species, some of which express altered circadian rhythmicity. In the wild‐type and in all rhythmic mutants (small optic lobes, sine oculis, small optic lobes;sine oculis), eight cell bodies at the anterior base of the medulla (PDFMe neurons) exhibit intense PDH‐like immunoreactivity. Four of the eight somata are large and four are smaller. The four large PDFMe neurons have wide tangential arborizations in the medulla and send axons via the posterior optic tract to the contralateral medulla. Fibers from the four small PDFMe neurons ramify in the median protocerebrum dorsal to the calyces of the mushroom bodies. Their terminals are adjacent to other PDH‐immunoreactive somata (PDFCa neurons) which send axons via the median bundle into the tritocerebrum. The results suggest a possible involvement of the PDFMe neurons in the circadian pacemaking system ofDrosophila. The location and size of the PDFMe neurons are identical with those of neurons containing theperiodprotein which is essential for circadian rhythmicity. Changes in the arborizations of the PDFMe neurons insmall optic lobes; sine oculismutants are suited to explain the splitting in the locomotor rhythm of these flies. In the arrhythmic mutant,disconnected, the PDFMe neurons are absent. The arrhythmic mutantper°, however, shows normal PDH immunoreactivity and therefore, does not prevent the expression of PDH‐like peptides in these neurons.© 19

ISSN:0092-7317    

DOI:10.1002/cne.903370202

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

年代:1993

数据来源: WILEY

摘要:

AbstractThe cutaneous innervation territories of the median, ulnar, and radial nerves to the hand were determined from neurophysiological recordings of peripheral mechanoreceptor axons in adult squirrel monkeys. These territories were then related to cutaneous receptive fields of cortical area 3b neurons to determine how low‐threshold inputs from each hand nerve map onto the primary somatosensory cortex.The results indicate that mechanoreceptor axons in each nerve innervate a continuous skin territory covering about 40% of the hand surface. The total territory of each nerve contains subregions of skin that are either autonomously innervated by that nerve or that receive overlapping innervation from more than one nerve. The autonomous, overlap, and total territories of each nerve are relatively constant from hand to hand. In the area 3b cortex, low‐threshold afferents from each nerve provide inputs to aggregates of cortical neurons. The cortical aggregates relating to the median and ulnar nerves are arranged as continuous, rostrocaudally oriented bands, whereas aggregates relating to the radial nerve are discontinuous and more patchlike. Similar patterns of bands and patches, and similar compression ratios of skin/cortical area, are seen across different monkeys.These findings demonstrate that the primary somatosensory cortex of normal adult primates contains bands or patches of neurons that are dominantly activated by low‐threshold inputs from specific hand nerves. This approach of delineating nerve territories and their related cortical dominance aggregates provides a useful means of analyzing cortical images of nerves and of quantitating peripheral and central patterns of deprivation after nerve injury. © 1993 Wiley‐L

ISSN:0092-7317    

DOI:10.1002/cne.903370203

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

年代:1993

数据来源: WILEY

摘要:

AbstractCalcium binding proteins calbindin D28k(CaBP) and parvalbumin (PV) are known to form distinct subpopulations of gamma‐aminobutyric acid (GABA)ergic neurons in the rodent hippocampal formation. Light and electron microscopic morphology and connections of these protein‐containing neurons are only partly known in the primate hippocampus. In this study, CaBP and PV were localized in neurons of the human hippocampal formation including the subicular complex (prosubiculum, subiculum, and presubiculum) in order to explore to what extent these subpopulations of hippocampal neurons differ in phylogenetically distant species.CaBP immunoreactivity was present in virtually all granule cells of the dentate gyrus and in a proportion of pyramidal neurons in the CA1 and CA2 regions. A distinct population of CaBP‐positive local circuit neurons was found in all layers of the dentate gyrus and Ammon's horn. Most frequently they were located in the molecular layer of the dentate gyrus and the pyramidal layer of Ammon's horn. In the subicular complex pyramidal neurons were not immunoreactive for CaBP. In the prosubiculum and subiculum immunoreactive nonpyramidal neurons were equally distributed in all layers, whereas in the presubiculum they occurred mainly in the superficial layers. Electron microscopy showed typical somatic and dendritic features of the granule, pyramidal, and local circuit neurons. CaBP‐positive mossy fiber terminals in the hilus of the dentate gyrus and terminals of presumed pyramidal neurons of Ammon's horn formed asymmetric synapses with dendrites and spines. CaBP‐positive terminals of nonprincipal neurons formed symmetric synapses with dendrites and dendritic spines, but never with somata or axon initial segments.PV was exclusively present in local circuit neurons in both the hippocampal formation and subicular complex. Most of the PV‐positive cell bodies were located among or close to the principal cell layers. However, large numbers of immunoreactive neurons were also found in the molecular layer of the dentate gyrus and in strata oriens of Ammon's horn. PV‐positive cells were equally distributed in all layers of the subicular complex. Electron microscopy showed the characteristic somatic and dendritic features of local circuit neurons. PV‐positive axon terminals formed exclusively symmetric synapses with somata, axon initial segments and dendritic shafts, and in a few cases with dendritic spines.The CaBP‐ and PV‐containing neurons formed similar subpopulations in rodents, monkeys, and humans, although the human hippocampus displayed the largest variability of these immunoreactive neurons in their morphology and location. Calcium binding protein‐containing neurons frequently occurred in the molecular layer of the human dentate gyrus and in the stratum lacunosum‐moleculare of Ammon's horn. The corresponding areas of the rat or monkey hippocampus were devoid of such neurons. In both rodents and primates similar populations of principal neurons contained CaBP. In addition, CaBP and PV were localized in distinct and nonoverlapping populations of nonprincipal cells. Their target selectivity did not change during phylogeny (e.g., PV‐positive cells mainly innervate the perisomatic region and CaBP‐positive cells the distal dendritic region of principal ce

ISSN:0092-7317    

DOI:10.1002/cne.903370204

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

年代:1993

数据来源: WILEY

摘要:

AbstractProjections from the nucleus tractus solitarii (NTS) to the spinal cord were demonstrated in the male Sprague‐Dawley rat. In retrograde transport studies, a horseradish peroxidase conjugate or a fluorescent dye, Fluoro Gold, were injected into midcervical or upper thoracic spinal segments. Most solitariospinal neurons were multipolar or bipolar and located between the obex and spinomedullary junction. Solitariospinal neurons were concentrated in proximity to the ventral border of the solitary tract and extended dorsally into the intermediate division and ventrolaterally into the intermediate reticular zone (IRt) of the lateral tegmental field. This subgroup predominantly projects to midcervical spinal segments. A subset of small neurons was retrogradely labeled from cervical or thoracic spinal segments in the medial commissural nucleus and contiguous with a periventricular group surrounding the central canal.In anterograde transport studies, iontophoretic deposits ofPhaseolus vulgarisleucoagglutinin were centered stereotaxically on sites in NTS identified by retrograde transport data. The lectin was incorporated by neurons of the solitary complex and transported bilaterally by axons that emerged from the nucleus and entered the reticular formation. The solitario‐reticular (transtegmental) pathway irradiated diagonally across the IRt and extended caudally into the cervical lateral funiculus and spinal gray. A small periventricular‐spinal pathway also descended longitudinally to the neuraxis. Solitariospinal neurons project to superficial lamina of the dorsal horn, laminae VII and X and ventral horn. The projections are predominantly contralateral to phrenic and intercostal motor nuclei and ipsilateral to the intermediolateral cell column. The solitariospinal projection represents the shortest route in the central nervous system, other than the local intraspinal reflex, through which first order visceral afferents signal cardiorespiratory and alimentary motor nuclei. © 1993 Wiley‐L

ISSN:0092-7317    

DOI:10.1002/cne.903370205

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

年代:1993

数据来源: WILEY

摘要:

AbstractPostmitotic neurons migrate from a zone(s) near the ventricles to the neocortex. During this migration, neurons associate with radial glia. After serving their role as guides for neuronal migration, the radial glia transform into astrocytes. Prenatal exposure to ethanol causes abnormal neuronal migration. We examined the effects of gestational exposure to ethanol on radial glia and astrocytes. Radial glia were stained immunohistochemically with the antibody RAT‐401, and astrocytes were labeled with an antibody directed against glial‐fibrillary acidic protein (GFAP). The subjects were the offspring of rats fed an ethanol‐containing liquid. diet (Et), pair‐fed a liquid control diet (Ct), or fed chow and water (Ch). During the first postnatal week, radial glial fibers (in Et‐treated rats and controls) stretched from the ventricular surface through the developing. cerebral wall to the pial surface. In the Et‐treated rats, the radial processes were less dense and more poorly fasciculated than they were in the Ch‐and Ct‐treated rats. Moreover, by postnatal day (P) 5, there was a significant reduction in RAT‐401 immunostaining in the Et‐treated rats, particularly in the superficial cortex. A similar reduction in control rats did not begin until P10. In all three treatment groups, GFAP‐immunoreactive astrocytes were in the cortex throughout the period from P1 to P45. In neonates, GFAP‐positive cells were distributed in the marginal zone (layer I) and the intermediate zone (the white matter). The number of GFAP‐positive cells in the cortical plate increased steadily with time so that, by P26, GFAP‐immunoreactive astrocytes were distributed evenly through all cortical laminae. Interestingly, between P5 and P12, the number of astrocytes was significantly greater in Et‐treated rats than in controls.Thus prenatal exposure to ethanol induces the premature loss of RAT‐401‐positive processes and the precocious increase in GFAP immunostaining. These ethanol‐induced changes in glial development indicate that ethanol accelerates the transformation of radial glia into astrocytes. Moreover, the ethanol‐induced premature degradation of the network of radial glial fibers may underlie the migration of late‐generated neurons t

ISSN:0092-7317    

DOI:10.1002/cne.903370206

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

年代:1993

数据来源: WILEY

摘要:

AbstractIn the present study, the compartmental organization of the nucleus accumbens was investigated by comparing the pattern of leu‐enkephalin immunoreactivity with that of the opioid receptor ligand, naloxone, an established marker for the compartmental organization of the neostriatum. Both patterns have a nonhomogeneous, patch‐like appearance throughout the rostrocaudal extent of the nucleus and show a good, mutual correspondence. In the core of the nucleus accumbens as well as in the border region between the nucleus accumbens and the caudate‐putamen, leu‐enkephalin‐rich areas are in register with opioid receptor‐dense areas. In the shell region the precise relationship between the enkephalin and the naloxone patterns could not be established. A comparison of the connectivity patterns and neurochemical characteristics of the opioid receptor‐dense compartments in the nucleus accumbens with those in the caudate‐putamen reveals major discrepancies between these two striatal subdivisions. We therefore conclude that, rather than a bicompartmental patch/striosome‐matrix organization, the nucleus accumbens has a multicompartmental organization. © 19

ISSN:0092-7317    

DOI:10.1002/cne.903370207

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

年代:1993

数据来源: WILEY

摘要:

AbstractStudies of neonatal and adult mammals have shown that neuronal morphology is regulated in part by the availability of target‐derived neurotrophic factor. To test whether the same is true for embryonic neurons, which are dependet on target‐derived neurotrophic factors for survival, we grew neural crest‐derived sensory neurons from the trigeminal ganglion of avian embryos of different ages in vitro in different concentrations of nerve growth factor (NGF) and measured the number of branch points and total length of the resulting arborizations. Although the size and complexity of arborizations increased with embryonic age up to embryonic day (E)14, neuronal morphology for embryos younger than E14 was unaffected by the concentration of NGF in the culture medium. However, beginning at E14, the stage at which trigeminal neurons start to lose their absolute requirement for NGF for survival, the neurons had significantly more branch points and larger arborizations in higher concentrations of NGF. Thus, it appears that the extent of neurite outgrowth in young embryos is independent of neurotrophic factor concentration; each neuron that receives enough neurotrophic factor to survive elaborates approximately the same size arbor. As trigeminal neurons mature and become less dependent on neurotrophic factor for survival, they acquire the ability to respond to neurotrophic factor with increased neurite growth and branching, as in neonates and adults. © 1993 Wiley‐L

ISSN:0092-7317    

DOI:10.1002/cne.903370208

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

年代:1993

数据来源: WILEY

摘要:

AbstractThe control of oviposition in the locust involves the expulsion of eggs from the lateral oviducts, a process believed to be under neurohormonal control. In this paper we have attempted to identify this putative hormone. Immunohistochemical staining of the brain retrocerebral complex and suboesophageal ganglion ofLocusta migratoriawith antiserum against FMRFamide revealed a number of FMRFamide‐immunopositive cells. FMRFamide‐like immunoreactivity was present in median neurosecretory cells and lateral neurosecretory cells of the protocerebrum. Other FMRFamide‐immunoreactive cells were detected in the deutocerebrum and tritocerebrum. Immunoreactive cell processes were observed in the mushroom bodies, the central body, the optic lobes, and in the axon tracts leaving the pars intercerebralis and tritocerebrum. FMRFamide‐like material was also seen in the circumoesophageal commissures. Further FMRFamide‐like material was present in cell bodies of the suboesophageal ganglion. FMRFamide‐like staining activity changed dramatically during the oviposition cycle in mature adult females. The median neurosecretory cells stained lightly immediately after oviposition and remained pale until the third day, when staining of perikarya and axon tracts increased. The staining intensity decreased on days 4 and 5. The titre of FMRFamide‐like material in the hemolymph increased during the vitellogenic cycle but plummeted after oviposition. A single band of FMRFamide‐like material was evident on immunoblot following sodium dodecyl sulphate‐polyacrylamide gel electrophoresis of adult female hemolymph. The approximate molecular weight of this molecule was 8,000. Gel permeation chromatography of hemolymph revealed a FMRFamide‐immunoreactive fraction with a molecular weight of 8,000. This fraction possessed myotropic activity when applied to the locust oviduct. It is argued that this molecule functions as an oviposition hormone in the locust.©

ISSN:0092-7317    

DOI:10.1002/cne.903370209

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

年代:1993

数据来源: WILEY

摘要:

AbstractWe studied the distribution of messenger ribonucleic acids coding for vasopressin and oxytocin in the human hypothalamus by means of hybridization histochemistry. Numerous large and medium‐sized neurons contain vasopressin messenger ribonucleic acid in the paraventricular nucleus, supraoptic nucleus, and accessory magnocellular nucleus. Small, lightly labeled vasopressin neurons also were detected in the suprachiasmatic nucleus. In addition, a relatively sparse band of mostly ovoid, medium‐sized vasopressin neurons mingle with unlabeled neurons of the lateral hypothalamic area; these cells extend dorsoventrally from the region ventral to the stria terminalis to the ventrolateral hypothalamus, sometimes transgressing the boundaries of nearby nuclei. We did not detect vasopressin gene expression in neurons of the bed nucleus of the stria terminalis proper, although some of the dorsal‐most labeled neurons of the lateral hypothalamus extend into the region of the caudal bed nucleus. Some lateral hypothalamic neurons also encroach upon other extrahypothalamic structures, such as the zona incerta. The nucleus basalis of Meynert complex was, with only rare exceptions, devoid of cells containing vasopressin messenger ribonucleic acid.Oxytocin messenger ribonucleic acid is found in the supraoptic nucleus, paraventricular nucleus, accessory magnocellular nucleus and, less frequently, in neurons of the lateral hypothalamus. In the hypothalamic magnocellular nuclei, oxytocin neurons are somewhat smaller than vasopressin neurons. Vasopressin cells outnumber oxytocin cells in the supraoptic nucleus, but their numbers are comparable in the paraventricular nucleus. As with vasopressin neurons, lateral hypothalamic oxytocin cells loosely span several diencephalic nuclei and encroach occasionally upon adjacent regions. These results confirm that the organization of vasopressin and oxytocin neurons in the human hypothalamus is largely comparable to that in nonhuman species and demonstrate the utility of hybridization histochemistry for elucidating the chemoarchitecture of the human brain.© 1993 Wiley‐

ISSN:0092-7317    

DOI:10.1002/cne.903370210

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

年代:1993

数据来源: WILEY

摘要:

AbstractThe glomerulus of the olfactory bulb may serve as a fundamental organizational unit for odor representation. In this context, the axons of olfactory receptor cells with similar response spectra may converge in specific glomerlui. While the topography between the olfactory epithelium and the olfactory bulb glomeruli has been explored, the characteristics of primary afferent terminal fields within glomeruli are poorly understood. To explore this issue, reconstructions of the terminal arbors of single olfactory nerve (ON) fibers within glomeruli were carried out in the rat olfactory bulb at the light microscopic level. Tissue samples prepared with the Golgi‐EM technique resulted in distinct impregnation of limited subsets of individual ON fibers. Following camera lucida reconstruction, quantitative analyses were made on selected sets of ON fibers and on the glomeruli they invaded. Most ON fibers began to arborize only after penetrating the glomeruli to a mean depth of approximately 35.9 μm. The fibers gave rise to a complex arbor of branches that was limited in total length (mean 157.7 μm) and the number of en passant varicosities or terminal enlargements (mean = 8.1). The number of varicosities and terminal boutons was proportional to the total length of branches. Also, there was a statistically significant correlation between the total branch length and the area (μm2) encompassed by the total arbor. The intraglomerular region supplied by the terminal arbor of an individual ON fiber was generally restricted. Given the recent molecular specificity attributed to olfactory receptor cells, this may provide a morphological basis for selective processing of signals encoded by specific receptors in the olfactory epithelium. © 1993 Wiley‐Li

ISSN:0092-7317    

DOI:10.1002/cne.903370211

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

年代:1993

数据来源: WILEY