bluuebunny/crossref_metadata_2025_split huggingface dataset:
Postnatal development of thalamic recipient neurons in the monkey striate cortex: Comparison of spine acquisition and dendritic growth of layer 4C alpha and beta spiny stellate neurons
Authors: Lund Jennifer S. , Holbach Suzanne M. 
Published: January 2005

AbstractA quantitative study has been made from Golgi impregnations of the maturation of dendrites and their spines on spiny stellate neurons in the macaque monkey primary visual cortex. The neurons studied lay within either the alpha or the beta division of lamina 4C; previous workers have shown the alpha division neurons to be contacted by thalamic axon terminals arising from the magnocellular division of the lateral geniculate nucleus (LGN) of the thalamus and the beta division neurons to be contacted by parvocellular LGN inputs. Most thalamic terminals and perhaps the majority of other, type 1 (Colonnier, '81), presumed excitatory, inputs to these cells make synaptic contacts on the tips of their dendritic spines. Measurement was made of relative changes in the total number of spines on these alpha and beta spiny neurons over age by measuring both spine density along the dendrites and dendritic arbor size in single 90‐m̈m sections from Golgi rapid preparations. Our previous work (Lund et al., '77; Boothe et al., '79) showed a marked proliferation and attrition of spines and dendritic branches to occur in the early postnatal weeks; Rakic et al. ('86) have since proposed that there is a cortexwide synchrony of synapse acquisition and loss during this same period. However, different visual capacities channelled via the magnocellular and parvicellular geniculate relays show different maturational rates (Harwerth et al., '86). This study indicates that the anatomical maturation of spines on the alpha and beta neurons is not temporally coincident from birth to 30 weeks. During this period, phases of spine acquisition and loss on alpha neurons precedes similar phases on beta neurons. The alpha neurons carry a peak spine population at 5–8 weeks postnatal, whereas the beta neurons carry their peak spine populations between 8 and 24 weeks postnatal.At all ages prior to 30 weeks, the two sets of neurons carry quite different total spine populations. Close to 30 weeks of age, the total spine coverage has fallen on both sets of neurons and becomes identical between the alpha and beta neurons. In animals aged 30 weeks to adult, spine coverage per neuron is maintained at a common figure for the alpha and beta neurons despite further growth and disparate dendritic arbor sizes and different local spine densities in the two groups; this suggests that some common sampling paradigm between pre‐ and postsynaptic elements is adopted by the alpha and beta neurons and also suggests the development of a close functional correlation between the two sets of neurons.
Dual mode of corticothalamic synaptic termination in the mediodorsal nucleus of the rhesus monkey
Authors: Schwartz Michael L , Dekker Jan J. , Goldman‐Rakic P. S. 
Published: January 2005

AbstractElectron microscopic autoradiography (EM‐ARG) was used to assess the synaptic organization of corticothalamic terminals in the parvicellular division of the mediodorsal thalamic nucleus. Examination of the synaptic organization in unreacted tissue revealed several distinct synaptic types distributed among glomerular and nonglomerular regions of the neuropil. Within glomeruli, three presynaptic terminal classes were found. The majority of profiles (as many as eight to ten per glomerulus) were presynaptic dendrites (PSDs) forming symmetric synaptic contacts with a central dendrite, and occasionally with other PSDs. One or two largo terminals densely packed with round vesicles (LR terminals) were also present in each glomerulus. This terminal class made multiple asymmetric contacts with the central dendrite, as well as with many PSDs within the glomerulus. Finally, small terminals with round vesicles (SR terminals) formed asymmetric synaptic junctions with PSDs in some glomeruli. PSDs and SR terminals were also found in the extraglomerular neuropil, although in different proportions than in the glomeruli. In the extraglomerular neuropil SR terminals were the most abundant terminal class and these terminals made synaptic contacts with dendrites of all sizes. PSDs were seen in considerably smaller numbers than in the glomeruli. Finally, the extraglomerular neuropil contained a moderate number of small to medium terminals that formed, symmetric synaptic junctions (SF terminals) with cell bodies and dendrites of all sizes.Synaptic profiles related to corticothalamic inputs were identified by injecting the prefrontal cortex of two rhesus monkeys with 3H‐leucine and ‐proline and analyzing the distribution and morphology of radiolabeled terminals. Quantitative analysis of the density of silver grains over different tissue compartments revealed a positive labeling index for two terminal classes: SR and LR terminals. Labeled SR terminals were concentrated in the extraglomerular neuropil and labeled LR terminals were found within glomeruli where they formed synaptic contact with the central dendrite, as well as with presynaptic dendrites of the glomerulus. In contrast to many other thalamic nuclei, cortical input to the mediodorsal nucleus arrives via two distinctive synaptic pathways, one terminating extraglomerularly and the other terminating within the synaptic glomeruli. The dual mode of corticothalamic terminations in the mediodorsal nucleus suggests a more potent and possibly different role for cortical input in the regulation of neuronal activity in this association nucleus than in sensory nuclei of the thalamus.
Common projection areas of antennal and visual pathways in the honeybee brain, apis mellifera
Authors: Maronde Ulrike 
Published: January 2005

AbstractThe convergence of primary sensory neurons of the antennae, higher order visual interneurons, and antennal motoneurons was analysed with neuroanatomical techniques in the honeybee, Apis mellifera. The different modalities evoke specific antennal responses in this insect. Three different fluorescent dyes were applied successively in the same preparation in order to visualise the various fiber projections from the antennae and the lobula in the brain of the honeybee. Three neuropile areas where sensory fibers of the antennae overlap with visual projection neurons from the lobula were found. Within the posterior‐median protocerebrum the antennal tract T6‐1 comes in close vicinity to the lobula tract Lo T‐9 and to some other lobula fibers that cannot be assigned to a special tract. Antennal T6‐3 fibers overlap with lobula LoT‐7 neurons within the posterior protocerebrum more laterally. Antennal T5 fibers arborise in the dorsal lobe and show common projection sites with lobula LoT‐3 neurons. The multimodal convergence in the three common neuropiles demonstrates that these areas are important centers for multimodal information processing between sensory, motor, and descending neurons in insects.
Dendritic architecture of nucleus ambiguus motoneurons projecting to the upper alimentary tract in the rat
Authors: Altschuler Steven M. , Bao Xinman , Miselis Richard R. 
Published: January 2005

AbstractThe motor innervation for palatal, pharyngeal, laryngeal, and esophageal muscles originates within the nucleus ambiguus. Although the viscerotopic organization of the upper alimentary tract in the nucleus ambiguus has been extensively studied, little information concerning the dendritic arborization of nucleus ambiguus motoneurons is available. The neural tracer cholera toxin‐horseradish peroxidase, which is particularly effective at revealing dendrites of retrogradely labeled neurons, was used to determine the dendritic architecture and organization of nucleus ambiguus motoneurons.In 72 rats, cholera toxin‐horseradish peroxidase in volumes of 1.0–18 m̈l was directly applied under pressure to the musculature of various sites along the upper alimentary tract. Motoneurons innervating the soft palate, pharynx, cricothyroid muscle, and cervical esophagus were all found to have extensive dendrites that extended into the adjacent reticular formation with a distinct pattern for each muscle group. In contrast, the dendrites of motoneurons innervating the thoracic and sub diaphragmatic esophagus were confined to the compact formation of the nucleus ambiguus. Dendritic bundling within the confines of the nucleus ambiguus was prominent following injection of tracer into the soft palate, pharynx, and esophagus. The bundles were primarily oriented in a rostrocaudal direction.These data suggest that the extensive extranuclear dendritic arborization of motoneurons innervating the soft palate, pharynx, larynx, and cervical esophagus provide a wide ranging target for multiple central afferents that may be involved in the differential control of muscles that participate in multiple complex motor functions. The lack of extensive extranuclear dendrites of motoneurons innervating the distal esophagus suggest that they receive focused central afferents. The prominent bundling of dendrites within the nucleus ambiguus may provide for synchronization of motoneurons innervating a specific muscle and perhaps for synchronization of motoneurons innervating different muscles acting in sequence.
Immunohistochemical localization of serotoninergic, enkephalinergic, and catecholaminergic cells in the brainstem and diencephalon of a cartilaginous fish, hydrolagus colliei
Authors: Stuesse Sherry L. , Cruce William L. R. 
Published: January 2005

AbstractWe localized serotonin (5‐HT), leu‐enkephalin (LENK), and tyrosine hydroxylase (TH) immunoreactive cells in the brain of a holocephalian, Hydrolagus colliei, by use of antibodies made in rabbit and the peroxidase‐antiperoxidase technique. Only three locations contained TH+ cells, the caudal myelencephalon, the locus coeruleus, and the diencephalon. Of these locations, the diencephalon contained the most cells and the locus coeruleus the least cells. The caudal TH+ myelencephalic cells formed a single large group that spanned both the dorsal and ventral portions of the brain (A1A2). The diencephalic TH+ cells were located in the posterior tuberculum, in the ventromedial and ventrolateral thalamic nuclei, and in the inferior lobe of the hypothalamus. Hydrolagus differed from mammals and the elasmobranchs, their sister group, in that no substantia nigra (A9), ventral tegmental area (A10), or A5 cell group was found.Distribution of LENK+ and 5‐HT+ cells were similar to each other; the raphe nuclei contained most of the 5‐HT+ and LENK+ cells. These 5‐HT+ and LENK+ cells were found at all rostrocaudal levels of the myelencephalon. The nucleus reticularis magnocellularis, reticularis magnocellularis lateralis, the ventral met‐ and mesencephalon (B7 and B9 cell groups), the hypothalamus, and the pretectal area contained additional 5‐HT+ and LENK+ cells. The solitary complex contained LENK+ cells but not but 5‐HT+ cells. A dorsal raphe nucleus, which is the largest 5‐HT+ cell group in mammals, was absent m Hydrolagus. A dorsal raphe nucleus is present in one galeomorph shark radiation but is absent in three radiations of batoids (rays, skates, and guitarfish). Thus even within cartilaginous fish, there are differences in the distribution of neurochemicals and possibly nuclei within their brains.
Expression of nerve growth factor (NGF) receptors in the brain and retina of chick embryos: Comparison with cholinergic development
Authors: von Bartheld Christopher S. , Heuer Josef G. , Bothwell Mark 
Published: January 2005

AbstractThe expression of nerve growth factor receptor (NGFR) transcripts was investigated with in situ hybridization techniques in the CNS of chick embryos from 3 days of incubation (E3) to 14 days posthatch (P14). The time course and distribution of NGFR expression was compared with the development of the cholinergic phenotype. Cholinergic properties were assessed by immunolabeling for choline acetyltransferase (ChAT) and histochemistry for acetylcholinesterase (AchE) activit.NGFR transcripts are expressed transiently in the inner plexiform layer and ganglion cell layer of the retina (E4–P1), neostriatum and hippocampus (E18), infundibular hypothalamus (E7–18), spiriform complex (E9–15), layers 2,3 (E9–18), and 10 (E11–18) of the optic tectum, nucleus mesencephalicus profundus, pars ventralis (E9–18), parvicellular isthmic nucleus (E7–P1), magnocellular isthmic nucleus (E9‐E18), nucleus semilunaris (E7–18), isthmo‐optic nucleus (E7–P14), rostral motor nuclei (E5–18), developing cerebellum (E7–15), internal granule cell layer (E11–18) and Purkinje cell layer (E15–P14) of the cerebellar cortex, and the inferior olivary nucleus (E9–15). A small number of neuronal populations with embryonic expression of NGFR remain strongly NGFR‐positive in the posthatch animal: habenular nuclei (labeled after E5), nucleus subrotundus (after E9), mesencephalic trigeminal nucleus (after E5), caudal parts of locus ceruleus and nucleus subceruleus (after E7), medullar reticular nuclei (after E11), and motor nuclei IX, X, and XII (after E9).The majority of neuronal populations with NGPR expression show cholinergic properties in development, and NGFR expression always precedes the onset of ChAT immunoreactivity. Postnatal expression of growth factor receptors is largely confined to neurons of the reticular type. NGFR expression in avian CNS nuclei differs from that in mammals. Early loss of NGFR expression in the cholinergic basal forebrain (which remains strongly NGFR positive in mammals) and persistent NGFR expression in parts of the avian locus ceruleus indicate changes of growth factor receptor expression and growth factor requirements in phylogeny. Knowledge of the time and distribution of NGFR expression in the chick embryo will facilitate the assessment of specific functions of NGF and NGF‐like molecules in an embryonic model with easy access for experimental manipulation.
Postembedding immunocytochemistry for GABA and glycine reveals the synaptic relationships of the dopaminergic amacrine cell of the cat retina
Authors: Kolb Helga , Cuenca Nicolas , Dekorver Laura 
Published: January 2005

AbstractPostembedding electron microscope immunocytochemistry of glycine and GABA conjugated to colloidal gold has been applied to pre‐embedded cat retina stained with the antibody against tyrosine hydroxylase (Toh+). Toh+ stained cells are the equivalent of A18 amacrine cells of Golgi descriptions (Kolb et al., 1981). The dendrites of Toh+ cells synapse upon several different types of glycine‐positive amacrine cell bodies. We suggest that these are the A8, A3/A4, and AII amacrine cell varieties by analogous immunocytochemical staining intensity, to glycine autoradiographic labeling intensity (Pourcho and Goebel, 1985). The greatest number of synapses from Toh+ dendrites are directed at the least glycine‐positive amacrine, which is the AII cell by all morphological criteria. A few glycine‐positive profiles are also presynaptic to the Toh+ stained cell body itself.Toh+ profiles are also presynaptic to GABA‐positive amacrine cell bodies. The commonest amacrine synapsed upon is very heavily labeled with GABA immunocytochemistry. We consider it to be the A17 amacrine cell, which is known to label strongly by [3H] muscimol autoradiography (Pourcho and Goebel, 1983). The cell body of the Toh+ amacrine cell also receives many synapses, which appear to be GABA‐positive, and Toh+ profiles running in stratum 1 of the inner plexiform layer (IPL) are both pre‐ and postsynaptic to GABA‐positive amacrine cell profiles. In addition, the cell body and primary dendrites of the Toh+ cell receive input from a bipolar type and GABA‐ or glycine‐negative profiles. GABA‐positive profiles, belonging to the interplexiform cell (IPC), are synapsed upon by Toh+ profiles that run in the outer plexiform layer (OPL). Horizontal cells identified on morphological criteria as the B‐type may also receive Toh+ synaptic input.
Development of the rabbit retina: II. Müller cells
Authors: Reichenbach A. , Schnitzer J. , Friedrich A. , Knothe A.‐K. , Henke A. 
Published: January 2005

AbstractMüller (glial) cells of the rabbit retina were stained with antibodies against the intermediate filament protein vimentin in retinal wholemounts from various developmental stages. Both the density of stained profiles and the mean diameter of these profiles were measured, with the microscope focus in the inner plexiform layer of the retinae. Within this retinal layer, every Müller cell possesses one stout vitread process; thus counts of the stained profiles allow an estimation of their number.After postnatal day (P) 9, the total number of stained cells was slightly above 4 million per retina; for the adult rabbit retina, this agrees well with earlier data obtained by our group based on another method, as well as with published data from other groups. We suggest that after P 9, only Müller cells are stained, and this population is numerically stable. In contrast, neonatal retinae contained significantly more stained profiles. This indicates that either the total number of Muller cells is reduced by “physiological cell death” or that additional cells are stained neonatally. We discuss why we favour the second possibility.After P 9, two peculiarities occur in the Müller cell population: (1) their density decreases gradually, to a greater extent in the retinal periphery than in the center (i.e., in the “visual streak”), and (2) Müller cell diameters increase, again more in the periphery than in the center. We argue that differential retinal expansion leads to dispersion of the pre‐existing cell population and allows for widening of the Müller cell processes. We conclude that Müller cells can be used postnatally in the rabbit retina as “landmarks” of expansion.
Sexually dimorphic distribution of neurotensin/neuromedin N mRNA in the rat preoptic area
Authors: Alexander Mark J. , Kiraly Zsolt J. , Leeman Susan E. 
Published: January 2005

AbstractNeurotensin release from estrogen‐responsive neurons in the rostral preoptic area of the female rat may play an important role in triggering preovulatory secretion of gonadotropin‐releasing hormone on proestrus. We investigated the possibility of sexually differentiated biosynthesis of neurotensin in the rostral preoptic area, using in situ hybridization histochemistry to detect neurotensin/neuromedin N (NT/N) mRNA in adult male rats and adult female rats at proestrus and the first day of diestrus. In sections through the anteroventral periventricular nucleus (AVPv), the number of labeled cells in proestrous females was four times that in males. Diestrous females exhibited half the number of labeled cells present at proestrus, and there was evidence for a significant correlation between circulating estradiol level and number of labeled cells in the AVPv. In the rostral portion of the medial preoptic nucleus (MPN), two contiguous groups of labeled cells were especially prominent. One group, in the medial half of the MPN, was located closer to the midline in females than in males and displayed greater labeling in males than in females. Furthermore, labeling in the rostral MPN was greater at proestrus than at diestrus. These results indicate that biosynthesis of neurotensin and neuromedin N in the rostral preoptic area may be sexually differentiated and, in the female, may vary across the estrous cycle in parallel with circulating estradiol levels, consistent with the view that neurotensin neurons in this area are involved in the regulation of preovulatory secretion of gonadotropin‐releasing hormone. The sex‐ and region‐specific expression of NT/N mRNA in the rostral preoptic area suggests functional heterogeneity of neurotensin neuronal populations in this area and implies complex regulation of NT/N gene expression in the rat brain.
Compartmental organization of the thalamostriatal connection in the cat
Authors: Ragsdale Clifton W. , Graybiel Ann M. 
Published: January 2005

AbstractThe compartmental organization of the thalamostriatal connection in the cat was studied by labelling thalamic fibers in anterograde axonal transport experiments and comparing their striatal distributions with the arrangement of striosomes and matrix tissue identified by histochemical staining methods. When analyzed according to their principal compartmental targets in dorsal striatum, the thalamic deposits indicated the existence of medial and lateral divisions within the thalamostriatal projection. Nuclei of the medial division, which includes parts of the thalamic midline, projected primarily to striosomes. The lateral division, which embraces the anterior and posterior intralaminar groups, the rostral ventral tier nuclei, and parts of the posterior lateral nuclear complex, predominantly innervated matrix tissue. In the dorsal division of the nucleus accumbens, the medial system preferentially terminated in zones that stain heavily in butyrylcholinesterase and substance P preparations, but fibers from both the medial and the lateral systems largely avoided the histochemically marked compartments such as the border islands of the nucleus accumbens that are seen elsewhere in the ventral striatum.Medial division: Thalamic deposits involving the paraventricular and rhomboid nuclei of the thalamic midline elicited labelling of striosomes and, invariably, ventral extrastriosomal matrix, the nucleus accumbens, and the amygdala. This projection was topographically organized: rostral thalamic deposits elicited labelling in the medial caudate nucleus and the medial nucleus accumbens. More caudal injections produced more lateral labelling.Lateral division: The lateral division is composed of at least three projection systems distinguished by their patterns of matrix innervation. Deposits involving the anterior intralaminar nuclei and the striatally projecting cells located lateral to the stria medullaris (anterior intralaminar complex) produced an even, diffuse labelling of the matrix tissue and weak labelling of the striosomes. Injections placed in the ventroanterior, ventrolateral, and ventromedial nuclei (rostral ventral complex) elicited fibrous labelling of matrix tissue that often showed nonstriosomal inhomogeneities. Deposits involving the centromedian and parafascicular nuclei (posterior intralaminar complex) produced a highly variable pattern of matrix labelling that included both homogeneous and decidedly patchy innervations of the extrastriosomal matrix. Each of these lateral thalamostriatal systems showed a similar spatial organization, whereby dorsoventral and mediolateral thalamic axes were roughly preserved in the projection to striatum.