bluuebunny/crossref_metadata_2025_split huggingface dataset:
Distribution of serotonin‐containing neurons and their pathways in the supraoesophageal ganglion of the cockroach Periplaneta americana (L.) as revealed by immunocytochemistry
Authors: Klemm Nikolai , Steinbusch Harry W. M. , Sundler Frank 
Published: January 2005

AbstractThe distribution of serotonin (5‐HT)‐containing neurons in the supraoesophageal (cerebral) ganglion of the cockroach Periplaneta americana was studied using immunocytochemistry and the formaldehyde histofluorescence method (Klemm, ′83). In this material immunocytochemistry was more sensitive than the formaldehyde histofluorescence procedure. A relatively small number of 5‐HT‐immunoreactive cell bodies (220–280) were found. For the first time, their processes could be followed. They highly arborize and innervate many brain regions. Three patterns of monoamine innervation have been demonstrated: (1) 5‐HT and catecholamine fibres (Klemm, ′83) occurring in the same region (e.g., outer lateral protocerebral neuropil, stratum caudale, mushroom body, fan‐shaped body, olfactory lobe), but having certain differences with respect to the organization of their projection fields; (2) 5‐HT fibres innervating a region lacking catecholamine‐containing fibres (pons); and (3) catecholamine neurons innervating a region lacking 5‐HT fibres (ellipsoid body). In the mushroom body only the extrinsic neurons contain 5‐HT immunoreactivity. They form a commissural fibre system linking the left‐ and right‐hand mushroom bodies and other brain regions. The pons is part of a 5‐HT‐neuron fibre system innervating many areas including the mushroom bodies. The present study demonstrates novel, complex, and widely distributed connections within the insect brain.
The organization of retinal maps within the dorsal and ventral lateral geniculate nuclei of the rabbit
Authors: Holcombe V. , Guillery R. W. 
Published: January 2005

AbstractThe cytoarchitectonic subdivisions in the rabbit's dorsal and ventral lateral geniculate nuclei have been related to the several retinal maps that can be defined in terms of the distribution of retinal axons within these nuclei. Destruction of different retinal sectors was combined with intravitreal injections of 3H‐proline, so that the distribution of fiber degeneration and autoradiographic label in the geniculate nuclei could be used to define the retinal maps in each nucleus, and to compare the two nuclei with each other. The two nuclei show surprisingly similar patterns of organization. Each is made up of a laminated alpha sector that curves around a relatively cell‐sparse beta sector. Two morphologically distinct layers of each alpha sector receive contralateral retinal afferents and between these there is a small region in receipt of ipsilateral afferents. In each nucleus, the lines of projection that represent single points in visual space pass perpendicular to the layers of the alpha sector and continue an almost straight course into the beta sector. Quantitative comparisons of the retinal maps show that the relative volumes devoted to the representation of segments of the visual field are approximately the same in the two nuclei.
Sexual differentiation in the terminal ganglion of the moth Manduca sexta: Role of sex‐specific neuronal death
Authors: Giebultowicz Jadwiga M. , Truman James W. 
Published: January 2005

AbstractIn the insect Manduca sexta the genitalia on the terminal abdominal segments are sexually dimorphic structures but they arise during metamorphosis from segments that are monomorphic in the larva. The motoneurons in the terminal ganglion that innervate these structures were examined by cobalt backfills of peripheral nerves. In the larval stage the population of motoneurons innervating the terminal segments was identical in both sexes. By contrast, the motoneuron populations in the terminal ganglia of adult males and females were strikingly different. No new motoneurons were produced during metamorphosis. Rather, this difference was the result of sex‐specific cell death which occurred primarily during the early stages of adult differentiation. Possible mechanisms underlying this sex‐specific degeneration of neurons are discussed.
Dendritic distribution of motoneurons innervating the three heads of the trapezius muscle in the cat
Authors: Vanner S. J. , Rose P. K. 
Published: January 2005

AbstractThe organization of the nuclei and dendritic architecture of motoneurons innervating the three heads of the trapezius muscle, clavotrapezius (CT), acromiotrapezius (AT), and spinotrapezius (ST), have been examined by using intracellular staining techniques. CT, AT, and ST motoneurons were found in the spinal accessory nucleus and were arranged in three overlapping subnuclei. CT motoneurons were primarily found in C2 and C3. In contrast, most AT motoneurons were found in C3, C4, and C5 and ST motoneurons were found in C4, C5, and the rostral parts of C6.Most dendrites of CT motoneurons, located in rostral C2, extended dorsally and many of these dendrites spread medially and laterally to encompass all of lamina VIII and the dorsolateral part of lamina VII. When viewed in the horizontal plane these motoneurons had a stellate appearance. The dendritic tree structure of CT motoneurons changed abruptly between rostral C2 and mid‐C2. The majority of dendrites of CT motoneurons located in the central and caudal parts of C2 projected rostrally and caudally to form a complex bundle of dendrites in the motoneuron nucleus. Small numbers of dendrites were also found ventromedial and dorsal to the soma. The dendritic trees of CT motoneurons in C3 and C4 and AT and ST motoneurons located in C4 and the rostral parts of C5 also followed this fusiform distribution pattern. The dendritic trees of AT and ST motoneurons in caudal C5 were not fusiform but instead had a complex distribution pattern which consisted of dendrites projecting in several directions. Many dendrites projected rostrally and caudally, and in addition, there were major dendritic projections ventrolateral and dorsolateral to the soma.These results indicate that each head of the trapezius muscle is innervated by two structurally dissimilar groups of motoneurons which occupy different spinal segments. Trapezius motoneurons at the same segmental level, regardless of which head of the trapezius muscle they innervate, have similar dendritic trees whose structure differs from those of neighbouring dorsal neck muscle motoneurons in C2, C3, and C4. Thus, the organization of motoneuron dendritic trees appears to be governed by several factors including the muscle innervated by the motoneuron and the transverse and segmental position of the motoneuron's soma.
Distribution of neurotensin‐immunoreactivity within baroreceptive portions of the nucleus of the tractus solitarius and the dorsal vagal nucleus of the rat
Authors: Higgins Gerald A. , Hoffman Gloria E. , Wray Susan , Schwaber James S. 
Published: January 2005

AbstractWe have examined the distribution of neurotensin immunoreactivity within subnuclear regions of the nucleus of the tractus solitarius (NTS) and the dorsal motor nucleus of the vagus nerve (DVN) in the rat. In order to determine which regions of the NTS were involved in the regulation of baroreceptor reflexes, we mapped the central distribution of the aortic branch of the vagus nerve using transganglionic transport of horseradish peroxidase. Comparison of the pattern of aortic nerve innervation with that of the distribution of neurotensin‐immunoreactive cells and fibers shows the dorsomedial nucleus of the NTS both to be the primary site of aortic baroreceptor termination and to contain the highest concentration of neurotensin‐immunoreactive elements within the NTS. Neurotensin‐immunoreactive fibers are also present in medial regions of the NTS adjacent to the area postrema where they may be involved in the modulation of vagal gastric afferents.Double‐label experiments, in which, on the same tissue sections, neurotensin immunohistochemistry was combined with retrograde horseradish peroxidase labeling of DVN neurons, reveal a topographic innervation of vagal preganglionic motoneurons by neurotensin‐immunoreactive fibers. The heaviest innervation is of lateral portions of the DVN and adjacent ventral portions of the NTS at the level of the obex, an area which may contain cardiac motoneurons. In this region neurotensin‐immunoreactive fibers can be observed in close proximity to retrogradely labeled cells.The concentration of neurotensin elements in a region of the NTS which is involved in the control of baroreceptor reflexes provides a morphological basis for the cardiovascular effects produced by central administration of the peptide. Additional control may be exerted at the level of the motoneuron, as evidenced by apparent neurotensin fiber innervation of presumptive cardiac preganglionic neurons. Similarly, the distribution of neurotensin fibers suggests that the peptide may be acting in gastric regulatory areas of the NTS or on vagal secretomotor neurons to regulate gastric acid secretion.
The monocular and binocular subfields of the rat's primary visual cortex: A quantitative morphological approach
Authors: Zilles Karl , Wree Andreas , Schleicher Axel , Divac Ivan 
Published: January 2005

AbstractPrimary visual cortex in the rat was studied by a variety of methods: transsynaptic transport of labelled amino acids, 2‐deoxyglucose, and staining for perikarya, myelin, and acetylcholinesterase. The analysis was aided by a computer‐controlled television image analyzer. The results obtained with different methods agree with one another in describing the position and extent of the entire primary visual cortex as well as its monocular (medial) and binocular (lateral) subareas.
Substance P, neurotensin, enkephalin, and catecholamine‐synthesizing enzymes: Light microscopic localizations compared with autoradiographic label in solitary efferents to the rat parabrachial region
Authors: Milner T. A. , Joh T. H. , Miller R. J. , Pickel V. M. 
Published: January 2005

AbstractThe immunocytochemical localizations of substance P, neurotensin, enkephalin and the catecholamine‐synthesizing enzymes tyrosine hydroxylase and dopamine‐β‐hydroxylase were examined in the rat parabrachial region. The immunoreactivity for each marker was compared with the distribution of superimposed autoradiographic labeling of parabrachial afferents after unilateral injection of 3H‐amino acids into the caudal portion of the medial nucleus of the solitary tract (m‐NTS). Substance‐P‐ and neurotensinlike immunoreactivity (SPLI and NTLI, respectively) were localized primarily in varicose processes in the ventrolateral quadrant of the parabrachial region. The SPLI and NTLI were differentially localized with respect to each other; however, both peptides were detected in regions of the parabrachial containing dense autoradiographic label. In contrast, enkephalinlike immunoreactivity (ELI), tyrosine hydroxylase, and dopamine‐β‐hydroxylase were detected in processes and a few perikarya located outside the ventrolateral parabrachial region. The ELI was primarily in the dorsolateral, and the catecholamine‐synthesizing enzymes were primarily in the medial parabrachial regions which contained sparse autoradiographic labeling of transported amino acids. We conclude that in the rat parabrachial region, SPLI and NTLI are contained within two distinct populations of afferents which may originate from perikarya in the caudal m‐NTS, whereas ELI and the cate‐cholamines are more likely to be found in other afferents or possibly in intrinsic neurons.
Postnatal development of the serotonin innervation of the hippocampus and dentate gyrus following raphe implants
Authors: Holets Vicky R. , Cotman Carl W. 
Published: January 2005

AbstractSerotoninergic (5‐HT) neurons derived from the embryonic raphe nuclear area (brainstem, embryonic days (E 16–18) were implanted into the entorhinal cortex of 6‐day‐old (P6) neonatal rat recipients which had received a fimbria lesion and entorhinal cortex ablation on P3. The hippocampus, dentate gyrus, and the raphe implant area were examined with 5‐HT immunohistochemistry 7, 14, 21, 30, and 60 days after implantation. The pattern of 5‐HT reinnvervation was compared to that of normal and lesioned animals, and to previous studies in which rats received septal or striatal implants. In the hippocampus adjacent to the implant 5‐HT‐immunoreactive fibers were first observed by 7 days postimplantation and increased in density and in their septotemporal and dorsoventral extent with increasing time postimplantation. Moderately dense fiber networks were diffusely distributed in the hippocampus and dentate gyrus at 30 and 60 days postimplant. Little, if any, indication of lamination was present. Retrogradely labeled neurons (the majority of which contained 5‐HT immunoreactivity) were observed in the raphe implant following injections of Fast Blue into the hippocampal formation. A few retrogradely labeled cells did not contain 5‐HT, methionine‐enkephalin (ME), or substance P (SP) immunoreactivity, although ME‐ and SP‐ immunoreactive neurons were observed in the implants. The lamination patterns and the increased density of 5‐HT‐immunoreactive fibers following a raphe implant into the entorhinal cortex clearly differ from the normal 5‐HT pattern and from the patterns of lamination following a striatal or septal implant.
The representation of the visual field in parvicellular and magnocellular layers of the lateral geniculate nucleus in the macaque monkey
Authors: Connolly Michael , Van Essen David 
Published: January 2005

AbstractTwo‐dimensional maps of individual layers of the dorsal lateral geniculate nucleus (LGN) in the macaque monkey were constructed and used as a basis for comparing laminar size, shape, and topographic organization. Topographical data from the electrophysiological investigation of the LGN by Malpeli and Baker ('75) were displayed on maps of all six layers. As known from previous studies, there is a significant over‐representation of central vision in the LGN. Unexpectedly, though, the visual representation is anisotropic over portions of most LGN layers. That is, the linear magnification factor (millimeters along the laminar surface per degree of visual field) is not equal for all directions from a given point in the visual field. Moreover, the visual representations in the parvicellular and magnocellular divisions of the LGN differ both in their emphasis on central vision and in their anisotropies.To determine the degree of individual variability, laminar maps were prepared from the LGN of seven other hemispheres. The shapes of laminar maps varied considerably between LGNs, from nearly circular to highly elliptical, but the surface area was relatively constant for each layer. Topographical organization, determined by mapping the optic disc representation on the LGN laminae and by labeling from anterograde and retrograde tracer injections in striate cortex, showed significant individual variability.Interestingly, the visual representations in the LGN and striate cortex are topologically inverted with respect to one another. This indicates that the establishment of geniculocortical connections involves a systematic crossing‐over of fibers.Information on cell densities and magnification factors in striate cortex obtained from other studies was compared to the results of the present study in order to estimate ratios of cortical neurons to LGN neurons at different eccentricities. The total number of cortical neurons per LGN neuron is about 130 on average, but it extends over approximately a tenfold range, from less than 100 in the far periphery to nearly 1,000 in the fovea. The estimated number of cells in layers 4A and 4Cβ per parvicellular layer neuron is smaller and extends over a slightly narrower range, from 30 to 240, whereas the number of layer 4Cα neurons per magnocellular neuron varies more widely, from about 45 to 7,000.
Regulation of axonal ingrowth into area dentata as studied by sequential, double intraocular brain tissue transplantation
Authors: Goldowitz Dan , Seiger Årke , Olson Lars 
Published: January 2005

AbstractThe anterior eye chamber was used as a model environment to study, in isolation, the interaction of embryonic area dentata transplants with transplants of one of three important sources of in situ innervation: entorhinal cortex, locus coeruleus or septal nuclei. None of these brain regions significantly affected the morphogenesis or in oculo growth of area dentata transplants. All three brain regions innervated the area dentata transplant. Entorhinal cortical transplants sent nerve fibers into a limited, and apparently specific, region of area dentata that was adjacent to the entorhinal transplant. This light innervation contrasts to the predominant innervation of area dentata by entorhinal cortex in situ. The fluorescent, noradrenergic neurons of locus coeruleus provided the area dentata transplant with an abundance of fine varicose nerve fibers. Given about 100 noradrenergic neurons in the locus coeruleus transplant and 4 to 6 months joint survival, the area dentata transplant was noradrenergically hyperinnervated. The cholinergic neurons of the septal nuclei transplant had a prolific ingrowth of acetylcholinesterase (AChE)‐positive nerve fibers to the area dentata transplant. There appeared to be a mutual exclusion between the extrinsic AChE‐positive fibers and the intrinsic Timm's‐positive granule cell mossy fibers in the area dentata transplant.We conclude that isolated replicas of the coeruleo‐, septo‐, and entorhinal cortico‐dentate pathways can be made through sequential intraocular double grafting. The nature of the in oculo connectivity between these replicates offers clues as to the mechanisms that might account for the regulation of nerve growth.
The fine structure of the lateral superior olivary nucleus of the cat
Authors: Cant Nell Beatty 
Published: January 2005

AbstractThe synaptic organization of the lateral superior olivary nucleus of the cat was analyzed under the electron microscope. The predominant cell type, the fusiform cell, has dendrites that extend from opposite poles of the cell body toward the margins of the nucleus, where they terminate in spinous branches. The fusiform cells are contacted by three types of synaptic terminals that can be distinguished by the size and shape of their synaptic vesicles. The somatic and proximal dendritic surfaces are apposed by synaptic terminals containing small, flat synaptic vesicles. Further from the cell body, the dendrites form numerous synaptic contacts with terminals containing large round vesicles as well as with the terminals containing small, flat vesicles. The most distal dendritic branches and their spiny appendages appear to form synapses almost exclusively with the terminals with large, round vesicles. A relatively rare type of terminal that contains small, round vesicles may form synapses with either the somatic or dendritic surfaces. A few small cells are interspersed among the fusiform cells, but they are more commonly located around the margins of the nucleus. The small cells form few axosomatic contacts.The simplest interpretation of the findings is that the terminals with small, flat vesicles arise in the medial nucleus of the trapezoid body and are inhibitory in function, whereas the terminals with large, round vesicles arise in the anteroventral cochlear nucleus and are excitatory; however, this remains to be demonstrated experimentally. In any case, the differential distribution of these two types of inputs on the somatic and dendritic surfaces must be an important determinant of the physiological response properties of the fusiform cells to binaural acoustic stimuli.
The effects of a lengthy period of environmental diversity on well‐fed and previously undernourished rats. II. Synapse‐to‐neuron ratios
Authors: Bhide P. G. , Bedi K. S. 
Published: January 2005

AbstractRats were undernourished from the 16th day of gestation until 25 postnatal days of age and then weaned on to an ad libitum diet. Around 35 days of age, 12 previously undernourished male rats were assigned to an enriched environmental condition (EC) and their littermates to an isolated environmental condition (IC). A parallel set of well‐fed rats was similarly assigned. After 80 days in these environmental conditions, all rats were killed by perfusion with 2% phosphate buffered glutaraldehyde.Small pieces of tissue containing the entire depth of the right visual cortex were embedded in Spurr's resin. Semithin (0.5 μm) sections were cut from these blocks and stained with toluidine blue. Photomicrographs of these sections were used to estimate the numerical density of neurons in cortical layers II to III. Ultrathin sections (∼ 70 nm) of the same region of cortex were then prepared for electron microscopy. These were used to estimate the mean synaptic disc diameter and synaptic numerical density. From these estimates of neuronal and synaptic numerical density, synapse‐to‐neuron ratios were calculated.The results of a two‐way analysis of variance test revealed that environment had significant effects on neuronal numerical density, mean synaptic disc diameter, and synapse‐to‐neuron ratios. Neither nutrition nor its interaction with environment had significant effects on any of the parameters analyzed. These results suggest that environmental diversity can produce alterations in certain neuronal and synaptic characteristics in the visual cortex of both well‐fed and previously undernourished rats.
Dendritic caliber and the 3/2 power relationship of dentate granule cells
Authors: Desmond Nancy L. , Levy William B. 
Published: January 2005

AbstractA quantitative examination of granule cell dendritic caliber and knowledge of dendritic lengths allows assessment of the distribution of dendritic membrane and the 3/2 power relationship at branch points. This paper presents caliber data of Golgi‐impregnated rat dentate gyrus. We used camera lucida drawings of the dendritic trees of 15 dorsal leaf and 15 ventral leaf granule cells to quantify mean dendritic caliber, dendritic taper, the 3/2 power relationship of parent and sibling dendritic diameters at branch points, and surface area.First‐order dendrites vary substantially in diameter. However, the mean caliber of all other dendrites is uniform across the proximal two‐thirds of the molecular layer for the dorsal and ventral leaves. The average diameter here is 1 μm. More distally, only mean ventral leaf dendritic caliber declines.Granule cell dendritic taper is due primarily to caliber decreases at branch points and not to a gradual decline in diameter across the length of a dendritic segment.Comparing the parent segment diameter raised to the 3/2 power with the sum of the 3/2 powers of the two sibling segment diameters reveals, for the dendritic tree located within the distal two‐thirds of the molecular layer, the desired 3/2 power relationship for the dorsal and ventral leaves. More proximally, where first‐, second‐, and third‐order dendrites branch sequentially across a 60–100‐μm extent, a 3/2 power relationship is not obtained.For the average dorsal leaf granule cell, dendritic surface area (without spines) is 11,984 μm2. The ratio of dendritic to somatic surface area is 28:1.Discussion of these data includes their implications for electrotonic modeling of the dentate granule cell.