摘要:

AbstractThe sources of ipsilateral cortical afferent projections to basoventral and mediodorsal prefrontal cortices that receive some visual input were studied with retrograde tracers (horseradish peroxidase or fluorescent dyes) in eight rhesus monkeys. The basoventral regions injected with tracers included basal (orbital) areas 11 and 12, lateral area 12, and ventral area 46. The mediodorsal regions included portions of medial area 32 and the caudal part of dorsal area 8. These sites represent areas within basoventral and mediodorsal prefrontal cortices that show a gradual increase in architectonic differentiation in a direction from the least differentiated orbital and medial limbic cortices toward the most differentiated cortices in the arcuate concavity. The results showed that the visual input to basoventral and mediodorsal prefrontal cortices originated largely in topographically distinct visual areas. Thus, basoventral sites received most of their visual cortical projections from the inferior temporal cortex. The rostral inferior temporal region was the predominant source of visual projections to orbital prefrontal sites, whereas lateral area 12 and ventral area 46 also received projections which were found more caudally. In contrast, mediodorsal prefrontal sites received most of their visual projections from dorsolateral and dorsomedial visual areas. The cells of origin were located in rostromedial visual cortices after injection of retrograde tracers in area 32 and in more caudal medial and dorsolateral visual areas after injection in caudal area 8. The latter also received substantial projections from visuomotor regions in the caudal portion of the lateral bank of the intraparietal sulcus. These results suggest that the basoventral prefrontal cortices are connected with ventral visual areas implicated in pattern recognition and discrimination, whereas the mediodorsal cortices are connected with medial and dorsolateral occipital and parietal areas associated with visuospatial functions. In addition, the prefrontal areas studied received projections from auditory and/or somatosensory cortices, from areas associated with more than one modality, and from limbic regions. Orbital area 12 seemed to be a major target of projections from somatosensory cortices and the rostral portion of medial area 32 received substantial projections from auditory cortices. The least architectonically differentiated areas (orbital area 11 and medial area 32) had more widespread corticocortical connections, including strong links with limbic cortices. In contrast, areas which showed the highest degree of architectonic differentiation within the basoventral (area 46) and the mediodorsal (area 8) prefrontal cortices had restricted corticocortical connections.

ISSN:0092-7317    

DOI:10.1002/cne.902760302

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

年代:1988

数据来源: WILEY

摘要:

AbstractWe have examined the development of catecholaminergic and cholinergic neurons in the retina of the rat by using antibodies against the enzymes tyrosine hydroxylase (TH) and choline acetyl transferase (ChAT), respectively. TH‐immunoreactivity was first detected at P (postnatal day) 3 in somata located in the inner part of the cytoblast layer (CBL) and in fine dendrites extending toward the middle of the inner plexiform layer (IPL). These cells were similar in shape and soma size to the class 2 TH‐immunoreactive (TH‐IR) cells of the adult rat. At P6, TH‐immunoreactivity was expressed by a second population of cells. Their somata were in the inner part of the inner nuclear layer (INL), but were distinctly larger, with short thick dendrites extending into the outer and/or middle parts of the IPL. Over subsequent days, the dendrites of these larger cells spread profusely in the outer part of the IPL, making it likely that they are the class 1 TH‐IR cells of the adult. ChAT‐immunoreactive (ChAT‐IR) cells were not detected until P15, when ChAT‐IR somata were observed in the ganglion cell layer (GCL) and INL, and their dendrites were observed already segregated into the distinct strata of the IPL in which they are found in the adult.The subsequent growth of TH‐IR somata of both classes was uneven, persisting longer in temporal than in nasal retina. This extended growth of temporal cells establishes the marked nasotemporal differences in soma diameter apparent among TH‐IR cells in the adult (Mitrofanis and Stone, '86; Mitrofanis et al., '88b). The growth and adult size of ChAT‐IR somata, on the other hand, did not vary with retinal position; their diameters were similar to those of the adult cells from the time they first appeared.The distribution of ChAT‐IR cells at P15 shared several features of the distribution of ganglion cells. The density of ChAT‐IR cells was greatest at the area of peak ganglion cell density and declined toward the periphery. In contrast, TH‐IR cells concentrated from the time they first appeared at the superior temporal margin, peripheral to the area of peak density of

ISSN:0092-7317    

DOI:10.1002/cne.902760303

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

年代:1988

数据来源: WILEY

摘要:

AbstractThe early postnatal development of cholecystokinin‐immunoreactive (CCK‐ir) neurons was analyzed in visual areas 17 and 18 of cats aged from postnatal day 0 to adulthood. Neurons were classified mainly by axonal criteria. According to their chronology of appearance neurons are grouped into three neuronal populations. Thefirst populationconsists of five cell types which appear perinatally in areas 17 and 18. Four of them have axons terminating in layer VI.Neurons with columnar dendritic fieldsof layers IV and V display a conspicuous dendritic arborization with the long dendrites always arranged parallel to each other. This way they form a vertically oriented dendritic column. The neurons differentiate at around P 2 and are present until the end of the second postnatal week. They disappear possibly by degeneration and cell death.Multipolar neurons of layer VIhave long dendrites and axonal domains of up to 800 μm in diameter. Three percent of these neurons send out two axons instead of only one. Neurons differentiate at P 0 and the cell type persists into adulthood.Bitufted to multipolar neurons of layer Vconstitute a frequent type; 10% of these cells issue two axons. They differentiate at P 2 and the type survives into adulthood.Bitufted to multipolar neurons of layers II/IIIappear at P 2 and send their axons into layer VI. So, early postnatally an axonal connection from superficial cortical layers to layer VI is established. The cell type persists into adulthood. The fifth cell type of thefirst populationis constituted by theneurons of layer Iwith intralaminar axons which differentiate at P 2. Although they derive from the early marginal zone, the cell type survives into adulthood.Thesecond populationconsists of two cell types which appear around the end of the second and during the third postnatal week in areas 17 and 18.Multipolar neurons of layer IIhave horizontally or obliquely arranged basket axons which, during the second postnatal month, form patches of high fiber and terminal density along the layer I/II border.Neurons with descending main axons issuing horizontal and oblique collateralsof layers II‐IV form broad axonal fields.Thethird populationin area 17 is constituted by three cell types:Bitufted neurons with axons descending in form of loose bundlesof layers II/III differentiate during the fifth postnatal week.Small basket cells of layers II/IIIwith locally restricted axonal plexuses and somewhat largerbasket cells of layer IVappear during the sixth and seventh week. The cell types form a dense terminal plexus which is concentrated in layer III/upper layer IV and in sublayer IVc in area 17. In contrast, no CCK‐ir basket neurons appear in layer IV in area 18, which therefore is only sparsely supplied with CCK‐ir fibers and does not display the particular innervation pattern observed in area 17.In conclusion, the formation of the adult CCK‐ir innervention pattern is the result of the sequential maturation ofthree neuronal populations.Concurrent with the maturation of thethird populationdifferences between the innervation pattern of area 17 and area 18 appear. One completely transient cell type is observed. Also individual neurons of persisting types, especially those of thefirst population, undergo degeneration and probably disappear by cell death. We assume that a certain neuronal turnover exists because, during the first 3 postnatal weeks, undifferentiated, fully differentiated, and degenerating neurons of the same type are concurre

ISSN:0092-7317    

DOI:10.1002/cne.902760304

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

年代:1988

数据来源: WILEY

摘要:

AbstractThe morphology of horizontal canal second‐order type I neurons was investigated by intracellular staining with horseradish peroxidase (HRP) and three‐dimensional reconstruction of the cell bodies and axons.Axons penetrated in and around the abducens nucleus were identified as originating from type I neurons by their characteristic firing pattern to horizontal rotation and by their monosynaptic response to stimulation of the ipsilateral vestibular nerve. A total of 47 type I neurons were stained. The cell bodies were located in the rostral portion of the medial vestibular nucleus (MVN) and were large or medium sized and had rather elongated shapes and rich dendritic arborizations. The neurons were divided into two groups: those which projected to the contralateral side of the brain stem (type Ic neurons) and those which projected to the ipsilateral side of the brainstem (type Ii neurons).All stem axons of type Ic neurons crossed the midline and bifurcated into rostral and caudal branches in the contralateral medial longitudinal fasciculus (MLF). Two or three collaterals arising close to this bifurcation distributed terminals in a relatively wide area in the contralateral abducens nucleus. Some of these collaterals projected further to the contralateral MVN and thus are vestibular commissural axons. Some of the rostral and caudal stem axons had collaterals which projected to the contralateral nucleus prepositus hypoglossi (PH), nucleus raphe pontis, or medullary reticular formation.There were at least six classes of type Ii neurons, most of which distributed to a relatively limited region in the ipsilateral abducens nucleus and they were categorized according to their future projections into the following categories: (A) no further collaterals beyond the abducens nucleus; (B) collaterals in the abducens nucleus and a branch descending and terminating in ipsilateral PH; (C) projected to the abducens nucleus, PH, and an area rostral to the abducens nucleus; (D) projected to the abducens nucleus and to ipsilateral reticular formation rostral and caudal to the abducens nucleus; (E) collaterals in the abducens nucleus and a thick caudal stem axon entering and descending in ipsilateral MLF; (F) a thick caudal stem axon entering and descending in ipsilateral MLF and no collaterals to the abducens nucleus. Some type Ii neurons also had recurrent collaterals which projected back to the ipsilateral MVN; these may inhibit type II neurons during ipsilateral rotat

ISSN:0092-7317    

DOI:10.1002/cne.902760305

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

年代:1988

数据来源: WILEY

摘要:

AbstractThe retinal topography of cells within the ganglion cell layer of three teleost species is examined in Nissl‐stained material in which all neuronal elements containing Nissl substance in the cytoplasm are counted. A topographic comparison is made with retrogradely labelled ganglion cells to differentiate the proportion of nonganglion cells not possessing an axon joining the optic nerve. In the three species studied 92%, 80%, and 66% were found to be the maximum proportion of true ganglion cells in the area centralis, horizontal streak, and periphery, respectively. The proportion of nonganglion cells in the total population of cells counted was 24%. The major contribution to this discrepancy is from peripheral nonspecialized regions of the retina. There is little difference in both topography and peak densities of retinal ganglion cells between the two techniques. The soma areas of both populations are analysed, with the homogeneous nonganglion cell population possessing cells between 5 and 15 μm2and the heterogeneous ganglion cell soma between 5 and 68 μm2, increasing in size with eccentric

ISSN:0092-7317    

DOI:10.1002/cne.902760306

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

年代:1988

数据来源: WILEY

摘要:

AbstractGlycine appears to be a major inhibitory neurotransmitter in the cochlear nucleus. In order to determine more precisely the distribution of glycinergic synapses, we have studied the immunocytochemical distribution of the glycine postsynaptic receptor. Two monoclonal antibodies were used, Gly Rec Ab 2, which recognizes the 48kD polypeptide and Gly Rec Ab 7, which primarily recognizes the 93kD subunit of the glycine receptor complex. At the light microscopic level, glycine receptor immunoreactivity was found throughout the ventral cochlear nucleus with a punctute distribution often found outlining large cell bodies. Indistinguishable patterns of staining were obtained with the two antibodies. Ultrastructural localization was done with Gly Rec Ab 7 because immunoreactivity remained after fixation with glutaraldehyde containing solutions. At the ultrustructural level, immunoreactivity was concentrated at postsynaptic sites on dendrites and cell bodies. In the anteroventral cochlear nucleus, neurons identified as spherical cells contained numerous inmunoreactive synapses on their cell bodies, whereas most immunoreactive synapses on stellate cells were on their proximal dendrites. In the posteroventral cochlear nucleus, neurons identified as octopus cells were immunoreactive on their cell bodies and proximal dendrites. In the granule cell layer, immunoreactivity was found only in the neuropile. Throughout the ventral cochlear nucleus, glycine receptor immunoreactivity was found postsynaptic to terminals containing flattened synaptic vesicles as well as those containing oval/pleomorphic synaptic vesicles.

ISSN:0092-7317    

DOI:10.1002/cne.902760307

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

年代:1988

数据来源: WILEY

摘要:

AbstractTransganglionic transport of horseradish peroxidase was used to study the potential for collateral sprouting of saphenous nerve afferent fibers in the lumbar dorsal horn of the adult rat following (1) combined unilateral saphenous nerve crush and ipsilateral sciatic nerve resection, (2) unilateral saphenous nerve crush, and (3) unilateral sciatic nerve resection. The saphenous nerve on the nonlesioned contralateral side served as control. Eight weeks after the lesion(s) the animals were subjected to bilateral application of horseradish peroxidase to the saphenous nerves. The distribution of the ensuing labeling in the superficial dorsal horn was subsequently mapped.Combined saphenous nerve crush and sciatic nerve resection resulted in expansion of the saphenous nerve projection area in the dorsal horn when compared to the nonlesioned control side (mean = 13%,P0.05). The findings indicate that in the adult rat, central processes of primary sensory neurons which are regenerating their peripheral processes can extend collateral sprouts into adjacent projection areas in the superficial dorsal horn subjected to previous deafferentation by peripheral nerve resection.

ISSN:0092-7317    

DOI:10.1002/cne.902760308

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

年代:1988

数据来源: WILEY

摘要:

AbstractThe distribution of cells and fibers that contain opioid peptides within the preoptic region of the rat was examined immunohistochemically. Cells and/or fibers that contain peptides derived from each of the three major opioid peptide families were differentially stained by using antisera that recognize unique derivatives of each precursor molecule and do not crossreact with members of the other opioid peptide families. A beta‐endorphin (ßE) antiserum was used to stain fibers that contain peptides derived from the proopiomelanocortin molecule, and dynorphin‐containing cells were identified by using an antiserum directed toward dynorphin B (Dyn B) that does not show detectable cross‐reactivity with enkephalin‐related peptides. An antiserum raised against peptide E (PE), which does not appear to cross‐react significantly with dynorphin peptides, was used to localize enkephalin cells and fibers. Each family of opioid peptides showed a unique distribution in the preoptic region. ßE‐immunoreactive fibers were primarily localized to the preoptic part of the periventricular nucleus, with moderate densities of fibers contained in the anteroventral periventricular nucleus (AVPv) and medial preoptic nucleus (MPN). Dyn B‐immunoreactive fibers showed a somewhat more uniform distribution throughout the region, and only a few Dyn B‐stained cells bodies were found within the medial preoptic area. In contrast, the preoptic region contained hundreds of PE‐immunoreactive cells, which were particularly numerous within the AVPv, MPN, and anterodorsal preoptic nucleus. The AVPv and MPN also contained discretely localized plexuses of PE‐stained fibers.Although the overall distributions of opioid peptide‐containing fibers within the preoptic region were quite similar in male and female rats, differential distributions of fibers were found in certain nuclei such as the AVPv and MPN, and they were correlated with previously identified cytoarchitectonic sexual dimorphisms. Such differential distributions were particularly distinct for enkephalin‐containing fibers. Although the AVPv is larger in female rats, it contained more PE‐immunoreactive cell bodies in male rats, and we have shown here that this sexual dimorphism appears to be at least partially dependent on perinatal levels of gonadal steroids. In contrast, no difference in the number of PE‐stained cells was found within the anterodorsal preoptic nucleus of male and female animals, indicating that sexual differences are not a general characteristic of enkephalinergic cells in the preoptic region of the rat. These findings suggest that gonadal steroids act during development to organize opiate‐containing pathways within the preoptic region, which may contribute to the expression of sexually differentiated physiol

ISSN:0092-7317    

DOI:10.1002/cne.902760309

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

年代:1988

数据来源: WILEY

摘要:

AbstractThe anatomic relationships between projections from the intermediate portion of the nucleus of the solitary tract (NTS) and phenylethanolamine N‐methyl transferaselike‐immunoreactive (PNMT‐LI) cells in the medulla oblongata were analyzed in Sprague‐Dawley rats by using two‐color immunoperoxidase staining combined with the anterograde transport ofPhaseolus vulgarisleucoagglutinin (PHA‐L). PHA‐L was iontophoretically deposited in the intermediate region of the NTS and the subjacent dorsal motor nucleus of the vagus (DMX) at the level of the middle of the area postrema. Blackstained PHA‐L‐immunoreactive (PHA‐LI) fibers and terminals were present throughout the length of the ipsilateral NTS, where many were seen in close apposition to amber‐stained PNMT‐LI cells belonging to the C2 cell group. Less profuse PHA‐LI projections were present in the contralateral NTS, especially at the level of the PHA‐L deposit. Bundles of smooth fibers emerged from the lateral edge of the DMX and could be followed to the ventrolateral surface of the medulla; these were likely vagal efferent fibers. PHA‐LI terminal arborizations were prominent in the region of the nucleus ambiguus (NA) and amongst PNMT‐LI cells in the lateral C1 cell group ventral to NA. Multiple sites of contiguity between PHA‐LI varicose fibers or boutons and PNMT‐LI cells in C1 were observed frequently and probably represent sites of functional connection.Medullary PNMT‐LI cells project to the intermediolateral cell columns of the spinal cord and to the hypothalamus and have been implicated in cardiovascular regulation. Based on the observations in this study, it is concluded that certain medullary PNMT‐LI cells in the C1 and C2 cell groups receive direct input from the intermediate NTS and thus play a role in baroreceptor‐me

ISSN:0092-7317    

DOI:10.1002/cne.902760310

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

年代:1988

数据来源: WILEY

ISSN:0092-7317    

DOI:10.1002/cne.902760301

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

年代:1988

数据来源: WILEY