摘要:

AbstractThis is the first in a series of papers investigating the neuroanatomical basis for the interaction of the amygdala and the hippocampal formation in the rhesus monkey. The present report focuses on the complementary and convergent projections of the amygdala and hippocampal formation to the entorhinal and perirhinal cortices. These results were obtained from complementary experiments using injections of radioactively labeled amino acids to identify the anterograde projection patterns and injections of horseradish peroxidase and fluorescent retrograde tracers to confirm the cytoarchitectonic location of the neurons of origin for each projection.The results of this investigation demonstrate that both the hippocampal formation and the amygdala project to the entorhinal and perirhinal cortices where, with a few exceptions, the major projections of each structure generally are found in different layers of the same cytoarchitecture subdivisions of the entorhinal cortex but overlap in the same layers of the perirhinal cortex. Thus, the lateral and accessory basal nuclei of the amygdala project to layer 3 of areas Pr1, 28I, 28L, and 28S, and the accessory basal nucleus projects strongly to layer 1 of these same areas. In contrast, the subiculum, prosubiculum, and subfield CA1 of the of the hippocampal formation all have a projection to layer 5 of these same areas. In area 28M, the accessory basal nucleus of the amygdala projects to layer 1, while the subiculum, prosubiculum, and subfield CA1 of the hippocampal formation all project to layer 5, and the presubiculum projects to layer 3.In addition to these complementary laminar projectios, there are a few areas of laminar overlap. Thus in area 28S, both the presubiculum and the CA1 subfield project to layer 3, where the lateral and accessory basal amygdaloid nuclei also project. Similarly, in 28I there is a major projection from the presubiculum and a lighter projection from the subiculum and CA1 to layer 3, where the lateral and accessory basal nuclei also project. There is also extensive laminar overlap in the perirhinal cortex. From the amygdala, the accessory basal nucleus projects to layers 1 and 3 and the lateral basal nucleus to layers 3, 5, and 6, while from the hippocampal formation, the prosubiculum projects to layers 3, 5, and 6, and the CA1 subfield projects to layer 5. This pattern of hippocampal and amygdaloid projections to the entorhinal and perirhinal cortices indicates that these cortices constitute a region of potentially extensive interaction between the amygdala and the hippocampus.

ISSN:0092-7317    

DOI:10.1002/cne.902710202

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

年代:1988

数据来源: WILEY

摘要:

AbstractThe pattern of direct connections between the amygdala and the hippocampal formation in the rhesus monkey (Macaca mulatta) was delineated by using both anterograde and retrograde tract‐tracing techniques.From the amygdala the accessory basal, medial basal, and the cortical nuclei and the cortical amygdaloid transition area send projections to the hippocampal formation. The efferents from the magnocellular part of the accessory basal nucleus and the cortical nuclei terminate in the molecular layer of subfields CA3, CA2, and CA1′, and to a lesser extent in the molecular layer and the superficial part of the pyramidal cell layers of the prosubiculum. In contrast, the projections from the medial basal nucleus and the cortical amygdaloid transition area terminate in the molecular layer and the superficial part of the pyramidal cell layers of the prosubiculum only.From the hippocampal formation, subfield CA1′ and the prosubiculum send efferents that terminate in the medial basal nucleus, the cortical transition area, and the ventral part of the cortical nuclei. In addition, the CA1′ subfield projects to the ventral, parvicellular part of the accessory basal nucleus.The present data emphasize an important role for the prosubiculum and the CA1′ subfield in medial temporal lobe area connections. Both regions, in addition to supporting direct connections between the amygdala and the hippocampal formation, also have extensive connections with the entorhinal cortex. As for the amygdala, the accessory basal nucleus sends efferents to both the hippocampal formation and the entorhinal cortex. The data demonstrate an anatomical means by which the amygdala, hippocampal formation, and the entorhinal cortex may interact. It is proposed that these connections may be important in the limbic memo

ISSN:0092-7317    

DOI:10.1002/cne.902710203

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

年代:1988

数据来源: WILEY

摘要:

AbstractThis paper describes the retrohippocampal projections of individual layers of the lateral entorhinal area as studied by the method of anterograde transport of the lectinPhaseolus vulgaris leucoagglutinin(PHA‐L) in the rat. As in the medial entorhinal area (EA), (Köhler, '86a) PHA‐L injections restricted to individual layers of the lateral EA resulted in labeling of sparse projections to the subicular complex (e.g., subiculum, pre‐ and parasubiculum), whereas projections to the perirhinal area and piriform cortex were prominent. All PHA‐L injections resulted in the labeling of axons projecting longitudinally within the entorhinal area, in both dorsal and ventral directions, albeit the ventral projections were the most prominent ones.PHA‐L injections into layers 2a and 2b resulted in labeling of axons that could be followed into layers 2a, 2b, and layer 1 on both sides of the injection site. Whereas numerous axons appeared to terminate in layer 2, most fibers ascended into layer 1, where they ran in a medial direction, passing the medial EA, around the parasubiculum to the presubiculum. Numerous axons were found to take a lateral route running past the lateral aspect of the lateral EA to the piriform cortex. The axons running medial in layer 2 did not enter the medial EA.After PHA‐L injections into layer 3, a large number of axons left the labeled cells on both sides of the injection site, in addition to massive projections that ascended into layers 2b, 2a and 1, just above the injection. Few axons entered layers 2‐6 of the medial EA, but numerous axons innervated layer 1, where they were found to run in the outer half of this layer. The axons running in a medial direction reached layer 1 of the presubiculum, whereas the laterally oriented ones innervated the molecular layer of the piriform cortex. PHA‐L injections into layer 4 resulted in massive labeling of projections to all superficially located layers. Layers 1, and 2b through 5 were innervated lateral to, and layer 4 medial to, the injection site.After a PHA‐L injection into layer 5, ascending projections were found innervating layers 1 through 4. The terminal fields were found to be particularly dense in the deep parts of layer 3 and in layer 1. This projection expanded laterally, but few projections reached into the medial sector of the lateral EA or into the medial EA.PHA‐L injections into layer 6 resulted in massive projections to layers 1 through 6 of the lateral EA. Layer 4 was among the most densely innervated layers of the lateral EA after this injection, and the innervation of layers 4 through 6 expanded into the medial EA after layer 6 injections.Taken together, these findings have shown that: (1) most of the projections from individual layers of the lateral EA are confined within this cortical area or run to extrahippocampal areas by way of the piriform cortex, and (2) with the exception of layers 4 and 6, the lateral EA sends few projections to layers 2 through 6 of the media EA or to the deep layers of t

ISSN:0092-7317    

DOI:10.1002/cne.902710204

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

年代:1988

数据来源: WILEY

摘要:

AbstractThe pretectal nucleus of the optic tract (NOT) was investigated immunocytochemically with an antiserum against gamma aminobutyric acid (GABA) employing the pre‐embedding peroxidase antiperoxidase technique at the light microscopic level and the postembedding colloidal gold technique at the electron microscopic level. GABA immunoreactivity was observed in cell bodies of different sizes and as punctate structures in the neuropil. In the electron microscope, besides immunoreactive dendrites, four different types of terminals were found to be GABA‐immunopositive; three types of terminals with clustered and flattened vesicles (F‐profile) and a fourth type with pleomorphic vesicles, presumably of dendritic origin (P‐profile). Both P‐and F‐profiles formed symmetrical synapses with dendritic profiles arranged in clusters ensheathed by glial elements. GABA‐immunopositive terminals were observed in synaptic contact with somata and retinal terminals (R‐profiles) that were always GABA‐immunonegative. Some GABA‐immunopositive somata showed presynaptic contacts with dendrites. The presence of GABA in numerous distinct elements in the NOT and the diversity in labeled somata and terminals demonstrate the importance of the inhibitor neurotransmitter in the NOT and suggest that its function is not limi

ISSN:0092-7317    

DOI:10.1002/cne.902710205

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

年代:1988

数据来源: WILEY

摘要:

AbstractThe rat interpeduncular nucleus (IPN) was immunocytochemically double‐stained for enkephalin (ENK) and substance P (SP) on the same sections. On the basis of both peptidergic distribution patterns and topographic relationship, the IPN was divided into nine subnuclei and one cap: the rostral subnucleus (IP‐R), the central subnucleus (IP‐C), the rostral‐lateral subnucleus (IP‐RL), the main lateral subnucleus (IP‐L), the caudal‐lateral subnucleus (IP‐CL), the dorsal‐lateral subnucleus (IP‐DL), the dorsal‐medial subnucleus (IP‐DM), the apical subnucleus (IP‐A), the intermediate subnucleus (IP‐I), and the dorsal cap (IP‐Cap). As the descriptions of the IP‐RL, IP‐L, and IP‐CL were inconsistent with previous reports, they were reevaluated; the IP‐RL was proposed as the region situated in the lateral portion at rostral levels and characterized by the lack of ENK and SP immunoreactive structures, the IP‐L as the region situated throughout the rostrocaudal extent in the lateral portion of the IPN and containing the highest density of SP immunoreactive fibers but no ENK immunoreactive fibers, and the IP‐CL as the region situated just laterocaudal to the IP‐L in the caudal pole of the IPN and containing ENK immunoreactive cells and fibers but no SP immunoreactive structures.Our results also showed that some cells in the IP‐R have both ENK and SP immunoreactivity. This coexistence was observed in some small spherical cells of the IP‐R, but rarely in larger oval‐shaped cells, which occasionally showed only ENK immunoreactivity. In addition, paired ENK immunoreactive fiber bundles entering the IP‐R were found to run just rostral to the paired SP immunoreactive columns, both of which composed parts of the interpedunculotegmental tract.A three‐dimensional model representing the subnuclear organization of the

ISSN:0092-7317    

DOI:10.1002/cne.902710206

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

年代:1988

数据来源: WILEY

摘要:

AbstractThe topography of retinal projections to the superior colliculus and dorsal lateral geniculate nucleus of a wallaby, the tammar (Macropus eugenii), was investigated by an anatomical method. Small laser lesions were made in the retinas of experimental animals, and the remaining retinal projections were visualized by means of horseradish‐peroxidase histochemistry. The position of each lesion was correlated with the position of the filling defects in the terminal label.The whole of the retina projects to the contralateral superior colliculus. The nasal retina is represented caudally, and the temporal retina rostrally. The ventral retina is represented medially, and the dorsal retina laterally. There is a projection to the ipsilateral superior colliculus, but it is patchy and its topography could not be determined by this method. The retinotopic map in the contralateral dorsal lateral geniculate nucleus has the nasal retina represented rostrally and the temporal retina caudally in the nucleus. The dorsal retina is represented ventrally, and the ventral retina is represented dorsally. It appears that the whole of the retina projects contralaterally, and in addition the temporal retina projects ipsilaterally. The maps of visual space through the two eyes were shown to be in topographic register in the binocular region by making a deposit of HRP in the visual cortex. This resulted in a column of retrogradely labeled cells in the nucleus. This column crossed the laminae, which are innervated by the ipsilateral and contralateral eye at right angle

ISSN:0092-7317    

DOI:10.1002/cne.902710207

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

年代:1988

数据来源: WILEY

摘要:

AbstractRetinal projections to visual centers in a marsupial mammal, the tammar wallaby (Macropus eugenii), have been investigated after an eye rotation prior to retinal innervation of the brain. Retinal topography to the superior colliculus and dorsal lateral geniculate nucleus was mapped by using laser lesions of the retina and horseradish peroxidase histochemistry. Despite the change in orientation of optic axon outgrowth from the developing eye after rotation, retinal ganglion cells made orderly connections in the colliculus and geniculate according to their original retinal position within the eye and not their rotated position. Axons must have corrected their pathways at some point between the back of the eye and their targets. The optic chiasm was one such site. Optic axons from the rotated eye took an abnormal course at the caudal end of the chiasm.Growth of optic axons through aberrant pathways in the brain did not preclude specific innervation of targets. When by chance optic axons entered through the oculomotor nerve root they specifically innervated their correct visual centers, albeit in reduced density, and did not innervate inappropriate targets. These results support the idea of specific interactions between growing axons, the pathways they grow along, and their targets.

ISSN:0092-7317    

DOI:10.1002/cne.902710208

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

年代:1988

数据来源: WILEY

摘要:

AbstractBy employing a combination of the immunohistochemistry for somatostatin (SRIF) and retrograde tracing with biotinylated wheat germ agglutinin (b‐WGA) injected into the posterior pituitary (group 1) or into the median eminence (group 2), functional topography of hypothalamic SRIF neurons was determined in the rat hypothalamus. In group 1, large numbers of WGA‐labeled neurons appeared in the rostral periventricular region and in the magnocellular division of the paraventricular and supraoptic nuclei; none of them were SRIF immunoreactive. In group 2, WGA‐labeled neurons were numerous in the rostral periventricular region, the parvicellular division of the paraventricular nucleus, and the arcuate nucleus; most of the WGA‐labeled neurons in the rostral periventricular region and some in the paraventricular nucleus were SRIF immunoreactive, but none in the arcuate nucleus showed immunoreactivity for SRIF. It is concluded that, in the rat hypothalamus, the locations of neurons containing hypophysiotrophic SRIF are confined within the rostral periventricular region and the parvicellular paraventricular nucleus. Our results do not support previous suggestions that SRIF immunoreactive axons innervate the posterior lobe of the pi

ISSN:0092-7317    

DOI:10.1002/cne.902710209

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

年代:1988

数据来源: WILEY

摘要:

AbstractThe morphological and functional differentiation of the olfactory receptor cells were investigated in developing rainbow trout (Salmo gairdneri) embryos by means of light and electron (transmission and scanning) microscopy and electrophysiology. Ciliated receptor cells first appeared when the olfactory placode was folded to form a groovelike structure rostrad to the eye at stage 24 (day 18; 18 days postfertilization). Ciliated receptor cells predominated until immature microvillar receptor cells developed in stage 28 (day 26) embryos. At stage 29, the day of hatching, the anterior edge of the olfactory epithelium contained only ciliated receptor cells, and the midregion contained both ciliated and microvillar receptor cells. Spontaneous neural firing activity was recorded from the olfactory mucosa as early as stage 25. The neural responses to amino acids were initially recorded from stage 26 embryos, containing sparse ciliated receptor cells with a few short cilia. The D‐enantiomers of amino acids were less effective. From these results we concluded that in rainbow trout the olfactory receptor cell has two separate morphological forms, ciliated and microvillar. These are ontogenetically distinct; the ciliated receptor cells preceded the microvillar. The ciliated receptor cells respond to amino acid stimulatio

ISSN:0092-7317    

DOI:10.1002/cne.902710210

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.902710211

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

年代:1988

数据来源: WILEY