bluuebunny/crossref_metadata_2025_split huggingface dataset:
Neuroanatomy of the visual afferents in the horseshoe crab (Limulus polyphemus)
Authors: Chamberlain Steven C. , Barlow Robert B. 
Published: January 2005

AbstractThe central nervous system of Limulus consists of a circumesophageal ring of fused ganglia and a paired ventral nerve cord. The anterior portion, the protocerebrum, receives sensory inputs including visual information. Three optic nerves, one each from the lateral eye, median ocellus, and ventral eye enter each side of the protocerebrum. The central connections of each optic nerve were determined by staining cut nerve trunks with cobalt chloride.The lateral optic nerve innervates the lamina, medulla, optic tract, ventral central body, and ocellar ganglion. The branching patterns of single axons, probably those of eccentric cells in the lateral eye retina, were observed. Single, large‐diameter axons in the lateral optic nerve ramify at seven loci including sites in each of the structures innervated by the lateral optic nerve as a whole.The median optic nerve innervates the ocellar ganglion, central body, optic tract, and medulla. Three types of branching patterns were observed for single, large‐diameter fibers in the median optic nerve. One type bypasses the ocellar ganglion and innervates the central body. A second type passes through the ocellar ganglion and optic tract without branching and innervates the posterior medulla. A third type innervates the ocellar ganglion, ventral central body, optic tract, and medulla.The ventral optic nerve is composed of large‐diameter axons of ventral photoreceptors. Each axon enters the ganglion cell layer of the medulla and branches over a planar area less than 150 μm in diameter.We also observed that axons from mechanoreceptors on the anterior carapace innervate the posterior neuropil of the medulla, and that about 5% of the neurons in the medullar ganglion cell layer send axons to the ipsilateral circumesophageal connective.
The dorsal nucleus of the lateral leminiscus in the cat: Neuronal types and their distributions
Authors: Kane Eileen S. , Barone Leesa M. 
Published: January 2005

AbstractThe normal population of neurons and their distributions within the dorsal nucleus of the lateral lemniscus were studied in both Nissl‐stained celloidin and frozen sections and in Golgi impregnations from brains of mature cats. According to axial measurements of somata in Nissl‐stained material, neurons of the dorsal nucleus of the lateral leminscus (DNLL) were classified by width:length ratio (r) into round (0.80 ≤ r ≤ 1.0), ovoid (0.65 < r < 0.80), or elongate (r ≤ 0.65) types. These same neurons could also be classed by average diameter (Dm) as large (Dm ≥ 22), medium (12.0 ≤ Dm < 22.0), or small (Dm < 12.0). A combination of data on ratios (shape) and average diameters (size) provided the following possible categories of Nissl‐stained, DNLL neurons: large round (LR), large ovoid (LO), large elongate (LE), medium round (MR), medium ovoid (MO), medium elongate (ME), small round (SR), small ovoid (SO), and small elongate (SE). Very few small cells were found, however. Quantitative studies of the distributions of cell types within the whole DNLL showed (1) most medium‐sized and most LE cells in the caudal third of the DNLL and (2) most LO and LR cells dorsally located in the rostral third of the DNLL. There were progressively more large and more round types along the caudal‐to‐rostral axis. In Golgi impregnations of the DNLL, all medium and large cell types, but no small cell types (defined in the Nissl study) were found. Golgi material showed (1) subdivisions of the LO class into vertical (LOV) and horizontal (LOH) types, and (2) radiate (MRR) and oriented (MRO) subclasses of MR neurons according to dendritic arbor and cytology, orientation within the DNLL, and axonal morphology. Examples from all classes of large cells (particularly, LE cells) could have ventrally directed axons. These ventrally directed axons might be efferents to the cochlear nueleus, known from our previous work. A strong horizontal orientation of most DNLL cell somata and dendrites, shown in both our Nissl and Golgi material, is discussed in relation to known inputs to the DNLL. Correlations of our morphological findings with limited electrophysiological data on the DNLL are also discussed.
Laminar distribution of receptive field properties in the primary visual cortex of the mouse
Authors: Mangini Nancy J. , Pearlman Alan L. 
Published: January 2005

AbstractWe studied the receptive field properties of single neurons in the primary visual cortex (area 17) of the mouse and the distribution of receptive field types among the cortical laminae. Three basic receptive field types were found: (1) Cells with oriented receptive fields, many of which could be classified as simple or complex, were found in all layers of the cortex, but occurred with greater frequency in layers II and III and less commonly in Layer IV. (2) Cells with non‐oriented receptive fields had ON, OFF, or ON‐OFF centers; they were found in all layers but were predominant in layer IV. Two subclasses of non‐oriented receptive fields were characterized based on their responses to stationary and moving stimuli. One group of cells with non‐oriented receptive fields responded vigorously with sustained firing to stationary flashing stimuli, and also responded well to moving stimuli and over a wide range of stimulus velocities. A second group of non‐oriented cells, termed motion‐selective, responded poorly or not at all to stationary stimuli and responded optimally to moving stimuli over a restricted range of velocities. (3) A distinct group of neurons, termed large field, non‐oriented (LFNO) cells, were found almost exclusively in layer V. LFNO cells had receptive fields that were larger than those of the other two major classes at all visual‐field locations; they also had higher rates of spontaneous activity and responded to higher stimulus velocities than the other classes. In these respects, LFNO cells resembled the layer V cells of area 17 in the cat and the layer V and VI cells of area 17 in the monkey that project to the superior colliculus. We injected horseradish peroxidase into the superior colliculus, and determined that corticotectal cells in the mouse were also located in layer V, the layer where we recorded LFNO cells. Additional evidence that some LFNO cells project to the superior colliculus was provided by preliminary experiments in which we stimulated the superior colliculus and antidromically activated cortical cells with LFNO receptive fields. Neurons with LFNO receptive fields thus constitute a class that is functionally distinct, with cell bodies that are located in a single layer (V) of area 17 in the mouse.
Three groups of cortico‐geniculate neurons and their distribution in binocular and monocular segments of cat striate cortex
Authors: Tsumoto Tadaharu , Suda Kouhei 
Published: January 2005

AbstractAmong 409 neurons recorded from binocular and monocular segments of the cat striate cortex, 91 were identified as cells (C‐G cells) projecting to the dorsal lateral geniculate nucleus (LGN) on the basis of antidromic activation from LGN and of histological localization of cortical layer VI. The axonal conduction velocity of these C‐G cells was calculated from differences in latency between antidromic responses to electrical stimulation of LGN and the optic radiation. According to this velocity, 70 C‐G cells from the binocular segment could be classified as fast (13–32 m/sec), intermediate (3.2–11 m/sec) and slow (0.3–1.6 m/sec) cells. The fast cells (47% of the total) were spontaneously active and had receptive fields of complex type. Histologically they were located mostly in the upper half of layer VI. The intermediate cells (31%) were mostly simple. The slow cells (21%) were completely silent, not driven by visual stimuli, and located mostly in the lower VI. From the monocular segment of the cortex, the intermediate cells could not be recorded, while the other two groups of cells were sampled with the same frequency as from the binocular segment. These findings suggest an existence of three functionally distinct groups of C‐G cells and a possible participation of the intermediate cells in binocular vision.
Brain stem projections of sensory and motor components of the vagus complex in the cat: I. The cervical vagus and nodose ganglion
Authors: Kalia Madhu , Mesulam M‐Marsel 
Published: January 2005

AbstractThe motor and sensory connections of the cervical vagus nerve and of its inferior ganglion (nodose ganglion) have been traced in the medulla oblongata of 32 adult cats with the neuroanatomical methods of horseradish peroxidase (HRP) histochemistry and amino acid autoradiography (ARG). In 14 of these subjects, an aqueous solution of HRP was applied unilaterally to the central end of the severed cervical vagus nerve. In 13 other cases, HRP was injected directly into the nodose ganglion. Three of these 13 subjects had undergone infranodose vagotomy 6 weeks prior to the HRP injection. A mixture of tritiated amino acid was injected into the nodose ganglion in five additional cats. The retrograde transport of HRP yielded reaction product in nerve fibers and perikarya of parasympathetic and somatic motoneurons in the medulla oblongata. Furthermore, a tetramethyl benzidine (TMB) method for visualizing HRP enabled the demonstration of anterograde and transganglionic transport, so that central sensory connections of the nodose ganglion and of the vagus nerve could also be traced. The central distribution of silver grain following injections of tritiated amino acids in the nodose ganglion corresponded closely with the distribution of sensory projections demonstrated with HRP, thus confirming the validity of HRP histochemistry as a method for tracing these projections. The histochemical and autoradiographic experiments showed that the vagus nerve enters the medulla from its lateral aspect in multiple fascicles and that it contains three major components—axons of preganglionic parasympathetic neurones, axons of skeletal motoneurons, and central processes of the sensory neurons in the nodose ganglion. Retrogradely labeled neurons were seen in the dorsal motor nucleus of X(dmnX), the nucleus ambiguus (nA), the nucleus retroambigualis (nRA), the nucleus dorsomedialis (ndm) and the spinal nucleus of the accessory nerve (nspA). The axons arising from motoneurons in the nA did not traverse the medulla directly laterally; rather, all of these axons were initially directed dorsomedially toward the dmnX, where they formed a hairpin loop and then accompanied the axons of dmnX neurons to their points of exit. Afferent fibers in the vagus nerve reached most of the subnuclei of the nTS bilaterally, with the more intense labeling being found on the ipsilateral side. Labeling of sensory vagal projections was also found in the area postrema of both sides and around neurons of the dmnX. These direct sensory projections terminating within the dmnX may provide an anatomical substrate for vagally mediated monosynpatic reflexes. Following deefferentiation by infranodose vagotomy 6 weeks prior to HRP injections into the nodose ganglion, a number of neurons in the dmnX were still intensely labeled with the HRP reaction product. The axons of these HRP‐labeled perikarya may constitute the bulbar component of the accessory nerve.
Evidence for the existence of a sexually dimorphic nucleus in the preoptic area of the rat
Authors: Gorski Roger A. , Harlan Richard E. , Jacobson Carol D. , Shryne James E. , Southam Arthur M. 
Published: January 2005

AbstractThe volume of an intensely staining component of the preoptic area of the male rat is markedly larger than that of the female. Moreover, its volume in both sexes is altered by perinatal hormone exposure consistent with the view that this brain region undergoes hormone dependent sexual differentiation. The present study was carried out to determine if this sexually dimorphic area of the brain has a greater cell density than that of the surround, and if a unique population or distribution of cells, either within one sex or between males and females, characterized this region. A single coronal paraffin section (10 m̈m) through the approximate center of this sexually dimorphic area in four adult gonadectomized rats of each sex was evaluated systematically. Each cell was labelled as being inside or outside of the sexually dimorphic area. In addition to cell density per unit area the following parameters were evaluated through a closed circuit video system: cell size, staining intensity, shape, and the presence of processes and of a nucleolus. The presence of a nucleolus was further used to identify neurons within the total population of almost 5000 cells that was evaluated. In both sexes, the sexually dimorphic area was characterized by a significantly increased cell density per unit area compared to that of the surround. On this basis, the term, the Sexually Dimorphic Nucleus of the Preoptic Area (SDN‐POA) is proposed, for this region. Moreover, the SDN‐POA of the male was characterized by increased neuronal density per unit area. The SDN‐POA in the male was also found to contain larger cells and neurons, as determined by direct measurement of their greatest diameter, as well as a greater percentage of cells and neurons rated large on a three‐point scale (small, medium, and large). No consistent differences in frequency distribution by stain intensity, shape, or the presence of cell processes were found to characterize the SDN‐POA or contribute to the sexual dimorphism. It is concluded that the marked sex difference in the volume of the SDN‐POA is due principally to an increase in the male of the total area of higher cell and neuronal density. However, the present results do not eliminate the possibility that more subtle differences in neuronal characteristics may exist in the SDN‐POA.
Basal ganglionic pathways to the tectum: Studies in reptiles
Authors: Reiner Anton , Brauth Steven E. , Kitt Cheryl A. , Karten Harvey J. 
Published: January 2005

AbstractRelations between the basal ganglia and the tectum were investigated in two different orders of reptiles: turtles (Chrysemys scripta) and crocodilians (Caiman crocodilus). In both species, efferents from the paleostriatal complex, a telencephalic region considered comparable to the mammalian basal ganglia on the basis of topographic, histochemical, and hodological criteria, were found to project to a prominent pretectal cell group called the dorsal nucleus of the posterior commissure (nDCP). Cells within nDCP, in turn, were found to project extensively upon the optic tectum. This paleostriatal‐pretectal‐tectal pathway is comparable to a previously described paleostriatal‐pretectal‐tectal channel in birds that involves a relay in the pretectal nucleus, spiriformis lateralis (SpL). Neither the presently described paleostriatal‐pretectal‐tectal channel of reptiles nor that previously described in birds, however, appears comparable to the superficially similar basal ganglionic‐nigral‐superior collicular pathway of mammals. Rather, data from the present experiments indicate the existence of a second paleostriatal channel to the tectum, one which does appear comparable to the basal ganglionic‐nigral‐superior collicular pathway of mammals. This second paleostriatal channel to the tectum, relayed via a tegmental cell group termed the substantia nigra in turtles and the tegmentipedunculopontine complex in caiman, is of much lesser prominence in reptiles than the paleostriatal‐pretectal‐tectal channel.The present results indicate the existence of at least two separate systems by which the basal ganglia in reptiles can influence the midbrain roof. These two channels, particularly the prominent paleostriatal‐prectectal‐tectal pathway, may represent major routes by which the basal ganglia influence motor functions in reptiles. Further, although previous research had only indicated the existence of a paleostriatal‐pretectal‐tectal pathway in birds and a basal ganglionic‐nigral‐collicular channel in mammals, existing data are consistent with the hypothesis that both presently described pathways in reptiles exist in birds and mammals, though only one of the two may be prominent in mammals.
The primate cochlear nuclei: Loss of lamination as a phylogenetic process
Authors: Kavanagh Moore Jean 
Published: January 2005

AbstractIn primates from prosimians to hominoids (lorisoid prosimians, marmoset and ceboid monkeys, cercopithecoid monkeys, and gibbon), there are differences in the location, depth, and extent of the granular layer of the cochlear nuclei. In the prosimians, the deep granular layer of the DCN is similar to that of other mammals, but there is, in addition, a superficial or subependymal layer of granule cells in the DCN. In ceboid and cercopithecoid monkeys, only a superficial or external granular layer is present in the DCN, and the granular layer over the VCN is much reduced. In the gibbon, there is no granular layer in either of the cochlear muclei. In conjunction with the progressive reduction of the cochlear granular layer in primates, fusiform cells lose their position as a radially oriented peripheral cell layer in the DCN and become located in the central region of the nucleus. These changes in primates are interpreted as resulting from failure of inward migration and increasing cell death in the ontogeny of the cochlear external granular layer, with concomitant changes occurring in the position and orientation of their target neurons, the fusiform cells.
Identification of parvocellular vasopressin and neurophysin neurons in the suprachiasmatic nucleus of a variety of mammals including primates
Authors: Sofroniew Michael V. , Weindl Adolf 
Published: January 2005

AbstractThe presence of parvocellular vasopressin‐ and neurophysin‐ containing neurons in the suprachiasmatic nucleus (SCN) was investigated in 13 mammalian species representing six mammalian orders (marsupials, rodents, lagomorphs, artiodactyls, carnivores, and primates), using specific antisera to vasopressin and neurophysin in the unlabelled antibody‐enzyme immunoperoxidase method. In all mammals examined, including man, parvocellular vasopressin and neurophysin neurons were found in the SCN. Only a portion of SCN neurons contain vasopressin and neurophysin, the number varying with species. Cell counts comparing the number of immunoreactive to Nissl‐stained neurons showed averages of 17% immunopositive neurons in the rat SCN, and 31% in the human SCN. No oxytocin‐containing SCN neurons were observed. These findings suggest that parvocellular vasopressin and neurophysin neurons are widely represented in mammals.
The organization of the extraocular motor nuclei in the atlantic stingray, Dasyatis sabina
Authors: Rosiles J. R. , Leonard R. B. 
Published: January 2005

AbstractRetrograde transport of HRP was used to determine the location and organization of the motor nuclei innervating the extrinsic eye muscles of the stingray, an elasmobranch fish. Oculomotor neurons are located both medial to and immediately ventrolateral to the MLF in the rostral midbrain. A ventral oculomotor nucleus was found among the IIIrd nerve rootlets close to the base of the midbrain. The dendrites of cells in the dorsal nucleus appear to be preferentially oriented in the transverse plane penetrating the MLF. Motoneuron pools innervating individual muscles are incompletely segregated in the dorsal group. However, the ventral nucleus innervates only the inferior oblique muscle. Dorsally, motoneurons innervating a single muscle are found on both sides of the MLF. In the caudal midbrain, the majority of trochlear motoneurons are located immediately ventrolateral to the MLF. Abducens motoneurons are scattered in the medulla from a ventrolateral position resembling the location of the nucleus in teleost fish to a dorsomedial position close to the MLF as in most other vertebrates. In contrast to other vertebrates, the medial rectus muscle is innervated by the contralateral oculomotor nucleus. Motoneurons innervating the other muscles have the same laterality as found in other vertebrates.
Topography of retinal representation in the rabbit cortex: An experimental study using transneuronal and retrograde tracing techniques
Authors: Holländer Horstmar , Hälbig Wolfgang 
Published: January 2005

AbstractThe cortical representation of the retina in rabbits was studied autoradiographically using transneuronal transport of tritiated proline and tritiated fucose. Injection of one eye produced cortical labelling on both sides. There was no indication of ocular dominance columns. On the contralateral side, the labelling was found in cortical layers II–IV, and partly also in layer VI of area striata and the caudal part of area peristriata, and in layer IV of most of area occipitalis. In addition, there was a patch of labelling in layers II–IV of the temporal cortex. On the ipsilateral side, the labelling was restricted to layer IV in a strip of cortex comprising area striata and area occipitalis along their common border. The cortical labelling in area striata and occipitalis was interpreted as evidence for a direct geniculo‐cortical projection. This was confirmed by demonstration of retrogrately labelled nerve cells in the lateral geniculate nucleus produced by small injections of horseradish peroxidase into area occipitalis and area striata. In experiments with intraocular injections of tritiated adenosine, transneuronal cortical labelling was much weaker and more diffuse. In addition to the neuropil, nerve cell bodies and glial cells were also labelled.
Gliogenesis of astrocytes and oligodendrocytes in the neocortical grey and white matter of the adult rat: Electron microscopic analysis of light radioautographs
Authors: Kaplan Michael S. , Hinds James W. 
Published: January 2005

AbstractThe identification of newly formed glial cells in the normal adult cerebral cortex is unresolved, since the identification of cells incorporating [H3] thymidine has not been demonstrated in the adult by electron microscopy. In the present study, this problem has been studied by combining the resolution of the electron microscope with radioautography of 1‐μm sections. Four normal male rats were injected at 90 days of age with [H3] thymidine and allowed to survive for 30 days. Labeled cells were found in 1‐μm sections of the visual cortex of these adult rats, and electron micrographs of selected cells from these same sections demonstrated clearly two types of cells labeled, astrocytes and oligodendrocytes, in both grey and white matter. The few cells that were tentatively identified as labeled microglia in the light microscope proved to resemble oligodendrocytes when examined in the electron microscope. In 1‐μm sections of the cortical grey matter, heavily labeled astrocytes (13 or more silver grains over the nucleus) represent about 0.08% of the total astrocytic population, and heavily labeled oligodendrocytes also were about 0.08% of their population. In the cortical white matter, about 0.03% heavily labeled astrocytes were observed, compared to about 0.07% heavily labeled oligodendrocytes. For all neuroglial cells in both white and grey matter, the average percent heavily labeled cells was 0.066%, a value large enough to suggest a slow turnover of neuroglial cells during the lifespan of the rats.