摘要:

AbstractTo determine the organization of visual inputs and outputs of the striatum, we placed multiple retrograde and anterograde tracers into physiologically identified portions of the striatum known to receive inputs from visual cortex in seven macaques. The injection sites included the tail and genu of the caudate nucleus (14 cases), the head of the caudate (1 case), and the ventral putamen (3 cases). Retrogradely labeled cells were located predominantly in layer 5 of the ipsilateral cortex but were also found in layers 3 and 6. After caudate injections, labeled cells were found both in large, nearly continuous regions of cortex topographically related to the site of the injection, and in several smaller cortical regions that were discontinuous and common to many or all of the injection sites. The continuously labeled regions included nearly all known visual cortical areas, except for the striate cortex. After injections in the rostral tail, the continuously labeled region included the rostral portion of Bonin and Bailey's (Urbana: University of Illinois Press, 1947) area TE and adjacent portions of TF, TH, TG, and, occasionally, area 35 (Brodmann, Leipzig; J.A. Barth, '09). After injections into the posterior tail and ventral genu, the labeled region shifted posteriorly in TE and TF, and into TEO and the ventral parts of prestriate areas V4, V3, and (sparsely) V2. As the injection site was advanced into the dorsal genu, the labeled region shifted dorsally toward the parietal lobe, including prestriate areas MT and PO, parietal area PG (Brodmann's area 7), the ventral and lateral intraparietal sulcal areas (VIP and LIP, respectively), and area PE and adjacent area LC (Brodmann's areas 5 and 23, respectively). The discontinuous areas labeled by many different injections included the principal sulcus/frontal eye field region, the anterior cingulate cortex, and the superior temporal polysensory area. Thus, whereas temporal, occipital, and parietal visual cortical areas project into the caudate largely according to proximity, certain multimodal cortical areas seem to have a much wider projection.To determine whether visual cortical areas have additional projections to the caudate beyond the territory of our retrograde injection sites in the tail and genu,3H‐labeled amino acids were injected into areas TE, V4, and MT in three additional monkeys. The topographic location of label in the tail and genu of the caudate in these cases was consistent with the results from injections of retrograde tracers into the caudate. However, in addition to label in the tail, the TE injection resulted in a separate moderate focus of label in the head of the caudate, confirming Van Hoesen et al. (J. Comp. Neurol., '81,199:205–219).Both retrograde and anterograde label was found in a number of subcortical sites. Labeled cells were found in the lateral basal nucleus of the amygdala, the substantia nigra pars compacta, the ventral tegmental area, and the parafascicular nucleus. The primary sites of anterograde label were the pars lateralis portion of the substantia nigra pars reticulata (SNr) and the caudal portions of the internal and external subdivisions of the globus pallidus (GP). Unlike the topographic arrangement of cortical inputs to the caudate, projections from distant portions of the tail and genu appeared to be highly convergent in both the SNr and GP. Because of the known projections from the lateral SNr to the superior colliculus and from the lateral SNr and caudal GP indirectly to prefrontal cortex, including the frontal eye field, the striatum may provide an important link in a visual pathway underlying oculomotor control and visuomotor associati

ISSN:0092-7317    

DOI:10.1002/cne.902980202

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

年代:1990

数据来源: WILEY

摘要:

AbstractInjections of cholera toxin B subunit conjugated to horseradish peroxidase (CTB‐HRP) were made into the lingual branch of the hypoglossal nerve in four species of finch in order to identify the innervation of the mechanoreceptors of the dermal papillae of the tongue, and simultaneously to determine the pattern of central projections of lingual hypoglossal afferents. The results showed that hypoglossal fibers innervate all the Herbst corpuscles and terminal cell receptors of the elaborately organized papillae of the dorsum of the tongue, of the shorter papillae in the ventral tongue, and the loose collection of Herbst corpuscles in the subpapillary region. Labelled fibers were also observed in the intralingual glands, in the intrinsic tongue muscles, and in the posterodorsal epithelium where they formed budlike structures.Retrogradely labelled cell bodies were located in the jugular ganglion and their central processes ascended and descended throughout the brainstem within the descending trigeminal tract (TTD). Terminal fields were observed within the dorsolateral part of the nucleus caudalis of TTD, predominantly ipsilaterally, and within the medial part of the dorsal horn of the first 4–6 cervical segments bilaterally. There were dense patches of termination over a dorsolateral subnucleus of the interpolated nucleus of TTD, and within two regions of the principal sensory trigeminal nucleus: a large one laterally and a small one medially.Terminal fields were also observed within the nucleus ventralis lateralis anterior of the rostral solitary complex, and within adjacent nuclei, which are probably equivalent to the dorsal sensory nuclei of the facial and glossopharyngeal nerves of other avian species.The results are interpreted in the light of the role of the tongue in species‐specific patterns of feeding in finches, and the possible requirement for the central integration of touch and

ISSN:0092-7317    

DOI:10.1002/cne.902980203

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

年代:1990

数据来源: WILEY

摘要:

AbstractAttempts are being made to unravel the local circuitry of the suprachiasmatic nucleus, with a view toward eventually correlating specific neuronal systems with circadian events. Hence, the vasopressinergic innervation of this nucleus in the laboratory mouse has been analyzed immunocytochemically at the light and electron microscopical levels. Monoclonal antineurophysin and polyclonal antivasopressin were used on aldehyde‐fixed brains. Serial vibratome sections of the appropriate forebrain region were prepared for pre‐embedding immunoperoxidase staining and/or postembedding immunogold labeling.Immunoreactive somata, processes, varicosities, and synaptic terminals were found throughout the suprachiasmatic nucleus, their ratio and density varying at different locations. The predominant type of vasopressinergic soma was ovoid to rounded (7–10 μm) containing secretory granules (85–120 nm), a large proportion of which were immunoreactive.Axon terminals, both nonimmunoreactive and immunoreactive, impinged upon vasopressinergic somata and processes, often displaying synaptic specializations. Vasopressinergic terminals, containing secretory granules and microvesicles, were found throughout the nucleus, particularly within the dorsomedial neuropil. These labeled terminals varied in size (0.4–3.4 μm2) and shape, ranging from compact boutons to pleomorphic profiles, some deeply indented by postsynaptic spines, either dendritic or somatic. Approximately 65% of the vasopressin‐containing terminals were axodendritic and 30% axosomatic; about 5% appeared to be axoaxonic. At least a quarter of all vasopressinergic synaptic terminals were axospinous.Other forms of interneuronal contact involving vasopressinergic elements (somata, dendrites) included extensive membrane to membrane appositional sites, and multiple puncta adhaerentia.The versatility of interconnections between vasopressin‐containing neurons in the mouse suprachiasmatic nucleus suggests a highly active and coordinated network, which contributes substantially to local intranuclear circuitry. In addition, a dense efferent vasopressinergic output is directed dorsally towards the periventricular hypothalamus, where direct associations may he established with diverse hypothalamic neuroen

ISSN:0092-7317    

DOI:10.1002/cne.902980204

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

年代:1990

数据来源: WILEY

摘要:

AbstractHuman area 17 is known to contain a single (the primary) visual area, whereas areas 18 and 19 are believed to contain multiple visual areas (defined as individual representations of the contralateral visual hemifield). This is known to be the case in monkeys, where several boundaries between visual areas are characterized by bands of callosal afferents and/or by changes in myeloarchitecture. We here describe the pattern of callosal afferents in (human) areas 17, 18, and 19 as well as their cortical architecture and we infer the position of some visual areas.Sections from occipital lobes of 6 human brains with unilateral occipital infarctions have been silver‐impregnated for degenerating axons, thereby revealing callosal afferents to the intact occipital cortex. Their tangential distribution is discontinuous, even in cases with large lesions. A band of callosal afferents straddles the area 17/18 boundary, whereas the remainder of area 17 and a 15–45 mm wide stripe of area 18 adjacent to the callosal band along the 17/18 border are free of them. Patches of callosal afferents alternate with callosal‐free regions more laterally in area 18 and in area 19. We conclude that, in man, a second visual area (analogue of V2) lies in area 18, horseshoe‐shaped around area 17, and includes the inner part of the acallosal stripe adjacent to the callosal band along the 17/18 boundary. The outer part of this acallosal stripe belongs to a third visual area, which may contain dorsally the analogue of V3 and ventrally that of VP. Thus the lower parts of the second and third visual areas lie on the lingual gyrus, whereas the analogue of the macaque's fourth visual area probably lies on the fusiform gyrus.Although the proposed subdivision of the occipital cortex relies largely on the pattern of callosal afferents, some putative human visual areas appear to have distinct architectonic features. The analogue of V2 is rather heavily myelinated and its layer III contains large pyramidal neurons. Its upper part is not well delimited laterally since adjacent “V3” has similar architecture. Its lower part, however, differs clearly from the adjacent “VP,” which is lightly myelinated and lacks the large pyramids in layer III. The cortex lateral to “VP” is heavily myelinated and contains fairly large pyramids in layers III and V. The myeloarchitecture of the lateral part of the occipital cortex is not uniform; a very heavily myelinated region stands out in the lateral part of area 19, near the occipito‐temporal junction. This region is likely to be the analogue of the

ISSN:0092-7317    

DOI:10.1002/cne.902980205

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

年代:1990

数据来源: WILEY

摘要:

AbstractThe distribution of neurotensin‐containing fibers was examined in the frontal cortex of the monkeyMacaca fuscatausing the immunoperoxidase histochemical technique. An extremely dense network of neurotensin‐containing fibers was observed in the medial prefrontal regions. The majority of cortical neurotensin fibers was observed in the anterior cingulate cortex (Walker's area 24) and adjacent medial prefrontal regions (areas 6 and 32). In area 24, the fiber density was similar to that in the nucleus accumbens. Immunoreactive fibers were particularly dense in two pyramidal layers (III, V). The medial prefrontal regions, areas 6 and 32, contained a moderate density of immunoreactive fibers. This regional distribution of neurotensin‐containing fibers was not observed in other cortical fiber systems that contained substance P, somatostatin, or tyrosine hydroxylase. No neurotensin‐containing cell bodies were observed in the frontal cortex.The present study demonstrates that the laminar and regional distributions of neurotensin‐containing fibers are unique when compared to those of substance P‐ or somatostatin‐containing fibers, and also distinct from that of catecholaminergic fibers. The distribution of telencephalic neurotensin fibers points to a relationship with limb

ISSN:0092-7317    

DOI:10.1002/cne.902980206

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

年代:1990

数据来源: WILEY

摘要:

AbstractThe synaptic organization of projections from the lateral mammillary neurons within the dorsal tegmental nucleus of Gudden is studied in the rat with the aid of anterograde transport of horseradish peroxidase conjugated with wheat germ agglutinin (WGA‐HRP) and visualized with tetramethylbenzidine. The dorsal tegmental nucleus consists of the pars ventralis (TDV) and the pars dorsalis (TDD). The normal neuropil of the dorsal tegmental nucleus contains three classes of axodendritic terminals, that is, terminals containing round, flat, and pleomorphic vesicles. They make up 44%, 5%, and 51%, respectively, of all axodendritic terminals in the TDV, and 62%, 1%, and 37% in the TDD.Injection of WGA‐HRP into the lateral mammillary nucleus permits ultrastructural recognition of many anterograde labeled terminals within both the TDV and TDD. In the TDV, 81% of the labeled terminals contain round synaptic vesicles and make asymmetric synaptic contacts. A few of the labeled terminals contain pleomorphic vesicles and make symmetric synaptic contacts. More than 50% of the labeled terminals contact intermediate dendrites (1–2 μm diameter). In the TDD, almost all labeled terminals are small, contain round vesicles, and make asymmetric synaptic contacts. These terminals mainly contact intermediate as well as distal (less than 1 μm diameter) dendrites. There are only a few labeled terminals with pleomorphic vesicles and no terminals with flat vesicles. The termination pattern of the lateral mammillary neurons in the TDV is similar to that in the TDD. Anterograde labeled axon terminals often contact retrograde labeled dendrites in the TDV. No reciprocal connections are present in the TDD. These results suggest that the TDV and the TDD receive mainly excitatory and a few inhibitory inputs from the lateral mammillary nucleus. The TDV neurons also have direct reciprocal connections with the lateral mammillary

ISSN:0092-7317    

DOI:10.1002/cne.902980207

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

年代:1990

数据来源: WILEY

摘要:

AbstractSpherical cells are a principal cell type of the electrosensory lateral line lobe (ELLL) and play a crucial role in the jamming avoidance response (JAR) behavior. SinceSternopygus, a low frequency gymnotiform genus, does not display a JAR we searched for spherical cells in its ELLL. While present inSternopygus, spherical cells differed remarkedly from those in the high‐frequency gymnotiforms,EigenmanniaandApteronotus.This study reveals species‐characteristic differences in the morphology and synaptology of the spherical cell, a projection neuron located in the deep neuropil layer (DNL) of the ELLL. In contrast to the adendritic spherical cell of other species, the spherical neuron inSternopygusexhibits an extensive basilar dendrite that extends into the primary electroreceptive afferent zone, the deep fiber layer (DFL). InSternopygus, these neurons are distributed evenly across the full length of each tuberous subdivision, with cell densities highest in the centrolateral subdivision. At the ultrastructural level, the contacts on the soma, proximal, and distal dendrite of the spherical neuron inSternopygusare asymmetrical chemical synapses, quite distinct from the electrotonic gap junctions found on the spherical neurons of other spec

ISSN:0092-7317    

DOI:10.1002/cne.902980208

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

年代:1990

数据来源: WILEY

摘要:

AbstractWe studied the immunocytochemical distribution of catecholaminergic fibers in the hippocampal formation from two cynomolgus monkeys by using phenylethanolamine‐N‐methyltransferase, dopamine‐beta‐hydroxylase, and tyrosine‐hydroxylase antibodies. There were no phenylethanolamine‐N‐methyltransferase immunoreactive fibers suggesting the lack of epinephrine containing fibers. In order to compare the distributions of tyrosine‐hydroxylase and dopamine‐beta‐hydroxylase immunoreactive fibers, we counted fibers in four hippocampal regions, the dentate gyrus, CA3, CA1, and the subiculum at three different rostrocaudal levels. The distributions of dopamine‐beta‐hydroxylase and tyrosine‐hydroxylase immunoreactive fibers were overlapping but clearly different, suggesting that the hippocampus receives both noradrenergic and dopaminergic inputs in primates. Dopamine‐beta‐hydroxylase‐immunoreactive fibers were present in moderate density and roughly evenly distributed throughout the hippocampus. Tyrosine‐hydroxylase immunoreactive fibers were found in high density in the dentate gyrus, in the stratum lacunosum‐moleculare, and in the molecular layer of the subiculum. There were only minor side‐side and rostrocaudal differences in the distribution of tyrosine‐hydroxylase and dopamine‐beta‐hydroxylase immunoreactive fibers. The identification of a putative dopaminergic projection to primate hippocampus, which is more dense and widely distributed than in the rodent, parallels similar increases in dopaminergic projecti

ISSN:0092-7317    

DOI:10.1002/cne.902980209

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

年代:1990

数据来源: WILEY

ISSN:0092-7317    

DOI:10.1002/cne.902980201

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

年代:1990

数据来源: WILEY