摘要:

AbstractThe topography of motoneurons supplying each of the six ocular muscles of the lamprey,Lampetra fluviatilis, was studied by selective application of HRP to the cut nerves of identified muscles. In addition, the distributions of motoneuron populations to both eyes were studied simultaneously with fluoresceine and rhodamine coupled dextran‐amines (FDA and RDA) applied to cut ocular muscle nerves of either side. The motoneuron pool of the caudal oblique muscle is represented bilaterally in the trochlear (N IV) motor nucleus. The dorsal rectus muscle is innervated from a contralateral group of oculomotor (N III) motoneurons and the remaining four muscles exclusively from the ipsilateral side (N III and N VI). The inferior and posterior rectus muscles are both innervated by the abducens nerve. In contrast to all jawed vertebrates, only three eye muscles (the dorsal rectus, rostral rectus, and rostral oblique) are innervated by the oculomotor nerve in lampreys (N III). Lampreys have a motor nucleus similar to the accessory abducens nucleus previously described only in tetrapods. They lack the muscle homologous to the nasal rectus muscle of elasmobranchs and the medial rectus muscle of osteognathostomes. The distribution of the dendrites of different groups of motoneurons was studied and is considered in relation to inputs from tectum and the different cranial nerve

ISSN:0092-7317    

DOI:10.1002/cne.902940402

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

年代:1990

数据来源: WILEY

摘要:

AbstractThe boundaries of the medial forebrain bundle (MFB) of the rat have been presented in previous work on the structure of this fiber system (Nieuwenhuys et al.:J. Comp. Neurol. 206:49‐81, '82). Neuronal cell bodies within these outlines constitute the bed nucleus of the MFB. Many fiber components of the MFB appeared to be spatially arranged within the bundle and featured an orderly topography (Veening et al.:J. Comp. Neurol. 206:82‐108, '82). As the fibers of the MFB are thought to be a major source of afferents to the bed nucleus (Millhouse: In P. J. Morgane and J. Panksepp (eds):Anatomy of the Hypothalamus, Vol. 1. New York: Marcel Dekker, pp. 221–265, '79), the latter has been subjected in this and the companion study (Geeraedts et al.:J. Comp. Neurol. 294:537‐568, '90) to a detailed cytoarchitectonic analysis. This analysis is based on continuous series sectioned in the three conventional planes. On the basis of cytoarchitectonic characteristics, including size and shape, staining intensity, packing density, and spatial orientation of the cell bodies, it was found that the bed nucleus of the MFB as described in the literature is by no means a cytoarchitectonic unit per se. Rather, the neuronal cell population located within the telencephalic stream of the MFB can be parcellated into a number of cellular groups, which partly or entirely belong to more‐or‐less known basal telencephalic structres. These structures are designated here as the MFB‐related areas. They correspond largely to the subcommissural substantia innominata (SIC), the sublenticular substantia innominata (SIL), the nucleus of the diagonal band of Broca, the olfactory tubercle, the magnocellular preoptic nucleus (POMA), the lateral preoptic area (LPOA), and the interstitial nucleus of the stria medullaris (ISM). The complex of the MFB‐related areas is surrounded by the following cellular entities: the nucleus accumbens (ACB), the caudatus‐putamen region (CPU), the globus pallidus (GP), the bed nucleus of the stria terminalis (BST), the anterior amygdaloid area (AAA), the amygdaloid nuclear complex (A), the medial preoptic area (MPOA)and the anterior hypothalamic area (AHA). Both MFB‐related areas and their surroundings have been identified and delimited in this study. This resulted in a new cytoarchitectonic atlas of the rat's basal telencephalon. Our atlas does not only show the relative positions of the above mentioned cellular groups, but also those of their subdivisions. The SIC, the SIL, the POMA and the LPOA have been parcellated into four, three, three, and six subareas, respectively; the GP, the BST, the MPOA, and the AHA into four, seven, fourteen, and six subareas, respectively. Several of these subdivisions have not been identified previously. The amygdaloid nuclear complex was not further parcellated cytoarchitectonically, as this was felt to be beyond the scope of our study. In preparing the atlas, it was kept in mind that the basal telencephalon should be parcellated in cellular groups and subgroups easily recognizable even by investigators not well trained in cytoarchitectonics.When the outlines of the MFB on the levels 1 to 4 of the atlas of the bun‐ dle (Nieuwenhuys et al.: J. Comp. Neurol. 206:49‐81, '82) are superimposed upon the corresponding tracings of our cytoarchitectonic atlas, the following cellular groups appear to constitute the rostral or telencephalic part of the bed nucleus of the MFR: the deep layer of the olfactory tubercle, the magnocellu‐ lar preoptic nucleus, the horizontal limb of the diagonal band of Broca, the lateral preoptic area and the sublenticular substantia innominata. After superimposing the areas of labeling of 21 autoradiographically identified fiber components of the MFB (Veening et al.: J. Comp. Neurol. 206:82‐108, '82) upon our tracings of the rostral bed nucleus, a remarkable correspondence appeared with the borders of the cytoarchitectonically defined cellular entities and those of the traversing fiber components to and from specific origins and destinations. These findings can be summarized as follows: the ventrolateral or POMA‐section of the MFB is occupied by olfactory related fibers; the ven‐ tromedial or LPOA‐section of the MFB contains septal, preoptic, and medial hypothalamic fibers; and the dorsal or SIL‐section of the MFB contains mesolimbic fibers, including fibers arising from the central amygdaloid nucleus, the bed nucleus of the stria terminalis, the ventral tegmental area, and the parabrachial nuclei of the brainstem region.Further morphological analysis of the connectivity of the neurons of the cellular entities of the rostral bed nucleus and their proposed dendritic rela‐ tionships with collaterals of the fibers of the MFB‐components will provide more profound information on the intrinsic organization o

ISSN:0092-7317    

DOI:10.1002/cne.902940403

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

年代:1990

数据来源: WILEY

摘要:

AbstractIn the preceding study (Geeraedts et al.:J. Comp. Neurol. 294:507‐536, '90), the rostral or telencephalic portion of the rat's bed nucleus of the medial forebrain bundle (MFB) has been parcellated into several cytoarchitectonically distinct cellular groups and subgroups. The purpose of the present investigation is to subject the caudal or lateral hypothalamic (LH) portion of the MFB bed nucleus to a detailed cytoarchitectonic analysis. This analysis is based on the same materials, methods, and cytoarchitectonic criteria that were also employed in the preceding study. In contrast to descriptions in the literature, it was found that the LH‐region constitutes a very heterogeneous population of neurons with an evident arrangement into groups, several of which have not been identified previously. Many of these cellular groups are partly or entirely located within the boundary of the LH‐trajectory of the MFB as previously established by Nieuwenhuys et al. (J. Comp. Neurol. 206:49‐81, '82). These groups are designated here as the MFB‐related cellular groups. They appear to be arranged into two longitudinal zones. Both zones are caudally replaced by the ventral tegmental area (VTA) and a part of the mesencephalic tegmentum (TEGM1). The lateral zone lies in close proximity to the internal capsule/cerebral peduncle and comprises the following cellular groups: the ventrolateral subarea of the lateral hypothalamic area (LHVL), the anterolateral subarea of the lateral hypothalamic area (LHAL), the lateral tuberal nucleus (TUL), the pre‐subthalamic nucleus (PSUT), the retro‐subthalamic nucleus (RSUT), the anterodorsal subarea of the lateral hypothalamic area (LHAD), and the lateral hypothalamic nucleus (LHN). The medial zone consists of the following cellular groups: the intermediate hypothalamic area (IHA), the medial tuberal nucleus (TUM), the perifornical nucleus (PFX), the lateral supramammillary nucleus (SUL), the submammillothalamic nucleus (SMT), and the nucleus geminus posterior (GEP). The cellular groups of the medial zone together with the tuberomammillary nucleus (TUMM) are positioned at the interface between the lateral and the medial hypothalamus, and form an array of cellular groups indicated in our study as the intermediate division of the hypothalamus. The MFB‐related cellular groups are dorsally, medially, ventrally, and laterally surrounded by rather well‐known brain structures. Both the MFB‐related cellular groups and the surrounding structures have been identified and delimited. This resulted in a new, elaborate cytoarchitectonic atlas of the rat's lateral hypothalamic region.When the outlines of the MFB on the levels 5‐9 of the atlas of the bundle (Nieuwenhuys et al.:J. Comp. Neurol. 206:49‐81, '82) are superimposed upon the corresponding tracings of our cytoarchitectonic atlas, the following cellular groups appear to constitute the caudal or lateral hypothalamic portion of the bed nucleus of the MFR: the LHVL, the LHAL, the LHAD, the TUL, the PSUT, the RSUT, the LHN. The GEP, the TEGM1, and, moreover, the lateral portions of the IHA, the TUM, the PFX, the SUL, and the SMT. After super‐ imposing the areas of labeling of 21 autoradiographically identified fiber com‐ ponents of the MFB (Veening et al.: J. Camp. Neurol. 206:82‐108, '82) upon the corresponding tracings of our atlas, we noted a certain correspondence with the borders of the cytoarchitectonically defined cellular groups and those of the fiber components. These data can be summarized as follows: the inter‐ mediate division of the hypothalamus contains septal, medial preoptic, and medial hypothalamic fibers; the ventrolateral or TUL/LHVL‐part of the MFB is occupied by olfactory related fibers; the dorsolateral part of the MFB, occupying the dorsolateral portion of the LHN‐region, is traversed by meso‐ limbic fibers; the central and dorsomedial portions of the LHN‐region are occupied by fibers arising from the lateral hypothalamus, the bed nucleus of the stria terminalis, the ventral tegmental area, and presumably also by fibers from (u

ISSN:0092-7317    

DOI:10.1002/cne.902940404

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

年代:1990

数据来源: WILEY

摘要:

AbstractIn the search for particular neurons that stain selectively and can be identified, the cerebral ganglia (brains) of the crayfishCherax destructorand the crabLeptograpsus variegatuswere immunocytochemically treated with a monoclonal antibody raised against substance P. Four large neurons in the cerebral ganglion of the crayfish and crab label selectively with a monoclonal antibody raised against substance P. Two of the large neurons have their cell bodies in the protocerebrum and two in the deutocerebrum in both animals. Each protocerebral cell in both animals projects through the ipsilateral and contralateral olfactory lobes to end among the lateral cell somata of the olfactory lobe and not in the neuropile. Electron micrographs show the presence of synapses within the cell somata area and on the cell somata themselves. Each deutocerebral cell in both animals projects only ipsilaterally and ends within the neuropile of the olfactory lobes. The immunoreactivity to substance P antibody and the shapes and the unique projections of the four cells suggest that they are homologous in the two species. Synaptic connections between axons and cell somata are rare in the arthropods but have been found on the Kenyon cells of the mushroom bodies ofLimulus. This raises questions about homologies between the crustacean olfactory lobe and the mushroom bodies ofLimulusand insects.

ISSN:0092-7317    

DOI:10.1002/cne.902940405

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

年代:1990

数据来源: WILEY

摘要:

AbstractWe have studied the morphology of single thalamocortical axons innervating area 3b of postcentral somatosensory cortex in macaque monkeys. We recorded from axons in the white matter below the representation of the hand in postcentral cortex in two monkeys (Macaca fascicularis) by using micropipettes filled with horseradish peroxidase (HRP). When an axon was recorded, we delineated its receptive field and determined its modality, and if cutaneous, whether it was slowly or rapidly adapting (SA or RA). We then impaled the axon and injected it with HRP. We recorded and successfully injected many more RA than SA axons, possibly because of differences in their true proportions. The RA axonal arbors varied in mediolateral extent from 350 to 800 μ with a mean of 600 μ One of the RA axons gave rise to four separate arbors spanning 2.5‐3.0 mm of cortex. The single SA axon we recovered was 370 μ in width. We suggest that the individual terminal zones underlie the columnar parcellation of the somatosensory cortex. The presence of arbors spanning several such columns suggests that all regions within the arbor may not be equally effective in driving cortical cells under normal conditions, and such arbors may provide the substrate for a cortical response to alterations in the pattern of i

ISSN:0092-7317    

DOI:10.1002/cne.902940406

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

年代:1990

数据来源: WILEY

摘要:

AbstractDescribed here is an aberrant parabigeminothalamic projection that follows neonatal lesions of the superior colliculus in rats, with evidence that this anomalous projection may sustain a normal number of neurons in the parabigeminal nucleus after early removal of the latter's tectal target. The aberrant projection was traced radioautographically to the tectorecipient zone of the lateral posterior nucleus after an injection of tritiated amino acid in the parabigeminal nucleus. Histochemical staining for cholinesterase revealed an anomalous patch of high enzyme activity in register with both the aberrant parabigeminothalamic projection and an abnormal retinal projection that also follows tectal lesions. Histochemical staining after either binocular enucleation or a tegemental lesion made simultaneous with the tectal ablation showed that the anomalous enzyme patch is a reliable marker of the aberrant parabiogeminothalamic projection. It was also shown that the retinal projection is not needed for the formation of the anomalous parabigeminothalamic pathway. Ablation of the superior colliculus at birth failed to produce a net cell loss in the contralateral middle division of the parabigeminal nucleus after the period of natural neuronal death. Lesions extending toward the anomalous terminal field in the lateral posterior nucleus, however, prevented the survival of a normal number of neurons in the parabigeminal nucleus. When the unilateral tectal ablation was made together with a lesion of the ipsilateral posterior neocortex that produced cell loss in the thalamus, the number of neurons remaining in the middle division of the contralateral parabigeminal were linearly related to the cell content of the lateral posterior nucleus. We conclude that the anomalous target in the tectorecipient zone of the lateral posterior nucleus effectively replaces the normal projection field in the superior colliculus, with regard to the trophic requirements for neuronal survival during development of the parabigeminal nucleus.

ISSN:0092-7317    

DOI:10.1002/cne.902940407

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

年代:1990

数据来源: WILEY

摘要:

AbstractThe present study was undertaken to establish the precise anatomical relationship of the subthalamic nucleus (STh) with limbic lobe‐afferented parts of the basal ganglia in the rat. The anterograde tracerPhaseolus vulgaris‐leucoagglutinin (PHA‐L), injected in the STh, the globus pallidus, the ventral pallidum, the ventral striatum, and the parafascicular thalamic nucleus, and the retrograde tracers Fluoro‐Gold (FG) and cholera toxin B (CTb), injected in the globus pallidus, the ventral pallidum, the ventral striatum, and the ventral mesencephalon, were used for this purpose. The results of these tracing experiments confirm the general notion of reciprocal connections between the STh and pallidal areas. Thus the dorsomedial part of the STh is connected with the subcommisural ventral pallidum, whereas a more ventral and lateral part of the medial STh is related to the medial globus pallidus. The lateral hypothalamic area, directly adjacent to the STh, containing neurons with a morphology quite similar to those in the STh, projects to parts of the ventral pallidum related to the olfactory tubercle. The reciprocal projection from this pallidal area to subthalamic regions appears to be very sparse. The medial STh sends strong projections to the medial part of the entopeduncular nucleus and the adjacent lateral hypothalamic area. Sparser projections from the medial STh reach the rostral and medial part of the caudate‐putamen and the nucleus accumbens. The nucleus accumbens. The nucleus accumbens sends a very sparse projection back to the medial STh. The projections of the medial STh to the ventral mesencephalon appear also to be topographically organized. The lateral hypothalamus and a few cells in the most medial part of the STh project to the ventral tegmental area, whereas progressively more lateral parts of the ventral mesencephalon, in particular the substantia nigra, receive input from successively more lateral and caudal parts of the STh. In addition, a number of STh fibers reach the midbrain extrapyramidal area. The lateral part of the parafascicular thalamic nucleus projects to the lateral part of the STh, whereas parafascicular neurons medial to the fasciculus retroflexus projects to the dorsomedial portion of the STh.The medial part of the STh and the adjacent lateral hypothalamus are intimately connected with limbic parts of the basal ganglia in a way similar and parallel to the connections of the lateral STh with motor‐related parts of the basal ganglia. These findings suggest a role for the STh in nonmotor functions of the ba

ISSN:0092-7317    

DOI:10.1002/cne.902940408

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

年代:1990

数据来源: WILEY

摘要:

AbstractThe mandibular closer muscles of the locust receive innervation that is immunoreactive for the putative transmitter 5‐hydroxytrptamine (5‐HT). Cobalt‐labelling suggests that the origin of this innervation is a group of cells located anteriorly in the suboesophageal ganglion. Bath application of 5‐HT while the muscles are active produces marked changes in the contractions, increasing their amplitude, rate of contraction, and rate of relaxation. Incubation of isolated muscles with 5‐HT shows that this amine elevates the levels of the cyclic nucleotide cyclic adenosine monophosphate (cAMP). In addition compounds that artificially elevate the levels of cAMP in the muscle‐3‐isobutyl‐1‐methylxanthine (IBMX), forskolin, and the cAMP analogue 8‐(4‐chlorophenylthio) cAMP‐mimic the actions of 5‐HT, whereas a potent inhibitor of insect adenylate cyclase, adenosine, considerably delays the onset of the effects produced by 5‐HT.The effects observed with 5‐HT in the mandibular muscle are similar to those of octopamine in the locust extensor tibiae muscle, and it is possible that this is a

ISSN:0092-7317    

DOI:10.1002/cne.902940409

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

年代:1990

数据来源: WILEY

摘要:

AbstractAs an initial effort to investigate possible inhibitory interactions in the olfactory system of the spiny lobster, studies were conducted to identify and localize the putative inhibitory neurotransmitters histamine and GABA in the olfactory lobe. Biochemical studies demonstrated that olfactory lobe tissue was capable of synthesizing histamine from radioactive histidine and GABA from glutamic acid. Immunohistochemistry was used to localize histamine and GABA in brain sections, by using either avidin‐biotin conjugated peroxidase or fluorescein conjugated secondary antibody. Specific histamine‐like and GABA‐like immunoreactivity was found in soma clusters of olfactory interneurons, adjacent to the olfactory lobe. Small, putative glial cells displaying intense histamine‐like immunoreactivity were found interspersed among the glomeruli of the lobe. The accessory lobe exhibited moderate immunostaining for both histamine and GABA. Positive immunostaining for histamine and GABA was also found in the olfactory lobes, with a predominance of staining in the outer caps of the glomeruli, which are thought to be the regions where the primary afferent terminals contact the processes of second‐order olfactory neurons. These findings collectively implicate inhibition at the first synaptic level of the olfactory pathway in the spin

ISSN:0092-7317    

DOI:10.1002/cne.902940410

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.902940401

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

年代:1990

数据来源: WILEY