bluuebunny/crossref_metadata_2025_split huggingface dataset:
The infrared trigemino‐tectal pathway in the rattlesnake and in the python
Authors: Newman Eric A. , Gruberg Edward R. , Hartline Peter H. 
Published: January 2005

AbstractWe have studied the infrared trigemino‐tectal pathway of the rattlesnake (Crotalus viridis) and the python (P. reticulatus). In the rattlesnake, horseradish peroxidase (HRP) injections into the nucleus reticularis caloris (RC) result in retrograde filling of cells in the ipsilateral nucleus of the lateral descending trigeminal tract (LTTD) and in the anterograde labelling of terminal fields in the contralateral optic tectum, confirming our previous finding of an RC‐tectal projection. The primary projection of the pit organ of the rattlesnake was traced by injecting cobalt chloride into the pit, demonstrating that the pit organ projects exclusively to the ipsilateral LTTD. Electrophysiological recording from single units in the RC shows that these cells respond to infrared stimulation. Taken together, these results demonstrate that the infrared pathway in the rattlesnake proceeds from the pit organ to the LTTD, to the RC, to the contralateral tectum. In contrast, HRP injection into the tectum of the python results in the retrograde filling of the large cells of the contralateral LTTD. Thus, a direct LTTD‐tectal projection occurs in the python. The cells of the rattlesnake RC and the larger cells of the python LTTD stain heavily for acetylcholinesterse activity and have a similar multipolar appearnce, suggesting that the tectal‐projecting cells in the two species may have a common origin.
Pattern of development of ascending and descending fibers in embryonic spinal cord of chick: II. A correlation with behavioral studies
Authors: Nornes Howard O. , Hart Henry , Carry Michael 
Published: January 2005

AbstractStudies on the embryonic spinal cord were extended to include the development of the ascending and descending fibers from the brachial level. This study was designed to correlate morphological development of the intersegmental system with physiological and behavioral observations of early embryonic behavior. Chick embryos were analyzed prior to day 6 of incubation, which is before closure of the reflex arc and arrival of supraspinal inputs to the embryonic spinal cord. Injections of 3H‐proline were made in the upper brachial level of chick embryos of stages 27–29 (5–6 days). The location of radioactive label in the marginal zone was analyzed autoradiographically to show the projection of labeled axonal flow from the site of injection. The majority of the labeled axons in the marginal zone was in the first 2–3 segments in both ascending and descending directions from the site of injection. By stage 27 (day 5), ascending labeled axons extended to the upper cervical level and labeled descending axons extended only about 4–5 segments to the upper thoracic level. By stage 29 (day 6) labeled ascending axons extended into the medulla oblongata, and labeled descending axons still extended only 4–5 segments caudally. These studies (Parts I and II) show that at stage 27 (day 5) there was considerable axoplasmic flow of radioactive label in the marginal zone from the lumbar to the brachial plexus but not in the opposite direction from the brachial to the lumbar plexus. Also, axoplasmic flow of label initially extended from the brachial plexus to the medulla oblongata sometime between stages 27–29. It was concluded that the intersegmental system of the embryonic spinal cord is well developed by day 6 of incubation and provides the neuro‐anatomical substrate for early embryonic behavior.
An axonal transport study of the ascending projection of medial lemniscal neurons in the rat
Authors: Feldman Sanford G. , Kruger Lawrence 
Published: January 2005

AbstractThe pattern of projection of the rat medial lemniscus was studied by axonal transport labeling following injections of tritiated leucine, proline and/or adenosine, or of horseradish peroxidase for retrograde identification of the neurons of origin. The vast majority of neurons in the gracile, cuneate, and principal trigeminal nuclei contribute to an almost totally crossed projection primarily to the thalamic ventrobasal complex. Additional thalamic components were traced to specific sites within the “posterior group”, including a medial component largely traversed by lemniscal axons and a caudolateral component lying between the principal nucleus of the medial geniculate and ventral nucleus of the lateral geniculate. We have designated this latter zone “intermediate geniculate”, distinguishing a somatosensory portion of the geniculate group on the basis of its myelo‐and cytoarchitecture, as well as its connections.Other projections replicated in several animals included the zona incerta and nearby sectors of the substantia nigra; three distinct mesencephalic arrangements within the deep layers of the superior colliculus, the external nucleus of the inferior colliculus, and the intercollicular nucleus; the anterior pretectal nucleus; dorsal sectors of the inferior olivary complex and the ipsilateral cerebellar cortex. The results are compared with findings in other species (with emphasis on the caudal thalamic region) in an attempt to resolve some of the apparent inconsistencies in nomenclature.
Sensory nerve endings in rhesus monkey sinus hairs
Authors: Halata Zdenek , Munger Bryce L. 
Published: January 2005

AbstractThe sensory innervation of primate sinus hairs has been studied by light and electron microscopy. For light microscopy paraffin sections as well as thick frozen sections were impregnated with silver and compared with serial semi‐thin sections of tissue prepared for electron microscopy. One type of sensory terminal is present in the epidermis surrounding the hair follicle, and four specific nerve terminals have been identified within the blood sinus. An epidermal rete ridge collar encircles the hair shaft and contains ∽200 Merkel cellneurite complexes. Numerous other Merkel cell‐neurite complexes are present in the external root sheath of the hair follicle beneath a thick glassy membrane innervated by ∽65 nerve fibers. At this level 10–15 lanceolate or palisade terminals are situated in the connective tissue. Up to 10 simple encapsulated corpuscles can be identified above the level of lanceolate endings and Merkel cell terminals. Ruffini corpuscles are closely applied to the glassy membrane below the lanceolate and Merkel terminals at the level where nerve fibers penetrate the capsule of the sinus. All of these terminals are supplied by 80–100 large diameter myelinated fibers distributed approximately as follows: 65 innervate Merkel cell‐neurite complexes, 15 to lanceolate, 10 to simple corpuscles, and 10 to Ruffini corpuscles. The innervation of the rete ridge collar is independent of that of the sinus consisting of 10–12 fibers derived from the superficial dermal network. Each of these sensory terminals can be correlated with specific functional parameters as described in numerous neurophysiologic studies. Merkel cell‐neurite complexes and Ruffini corpuscles are slowly adapting receptors; lanceolate terminals and simple corpuscles are rapidly adapting receptors.
Medullary and cerebellar projections of the statoacoustic nerve of the dogfish, Scyliorhinus canicula
Authors: Boord Robert L. , Roberts Barry L. 
Published: January 2005

AbstractThe statoacoustic nerve of the dogfish, Scyliorhinus canicula, was transected medial to the ganglion for the purpose of elucidating its central pathways and terminal fields. Following two to six weeks postoperative survival times, transverse, horizontal, and sagittal sections of the brain stem were stained by the Fink‐Heimer silver‐impregnation method to reveal degenerating axons and terminals. Fragmented axons enter the medulla and give rise to medial, descending, and ascending pathway. Fibers of the medial pathway terminate about the soma and lateral dendrites of the large cells that comprise nucleus magnocellularis; descending and ascending flbers terminate on the dendrites of the cells of ventral and superior nuclei respectively. In addition, fibers emanate from fascicles of the descending pathway to form a large field of degenerating axons and terminals within the ventromedial part of the medulla, and a substantial proportion of the fibers of the ascending pathway continues beyond the superior nucleus to terminate among the granule cells of the medial part of the vestibulolateral lobe of the cerebellum. No fragmented axons are traceable to the lateral part (auricles) of the vestibulolateral lobe, cerebellar nucleus or corpus, or those nuclei associated with the lateral‐line lobes. It appears therefore that octavus terminal fields are separate from those of the lateral line at both cerebellar and medullary levels, at least at the level of the first‐order neuron.
Binding of horseradish peroxidase‐α‐bungarotoxin to axonal membranes at the node of ranvier
Authors: Freedman Steven D. , Lentz Thomas L. 
Published: January 2005

AbstractThe binding of horseradish peroxidase (HRP)‐labeled α‐bungarotoxin (α‐BuTx) was investigated in rat sciatic nerve. Activity was found to be localized to the axolemma of myelinated nerve fibers at the nodes of Ranvier. Activity was also seen in other regions of the axolemma where the myelin sheath was separated from the axon by enzymatic treatment. Pretreatment of nerves with native α‐BuTx or curare blocked the binding of HRP‐α‐BuTx to the axonal membranes. This study demonstrates binding of α‐BuTx to axonal membranes although the nature and significance of the toxin receptor is uncertain.
Retinotopic organization of striate and extrastriate visual cortex in the mouse
Authors: Wagor Earl , Mangini Nancy J. , Pearlman Alan L. 
Published: January 2005

AbstractDetailed retinotopic maps of primary visual cortex (area 17) and the extrastriate visual regions surrounding it (areas 18a and 18b) have been constructed for the C57BL/6J mouse using standard electrophysiological mapping techniques.Primary visual cortex (area 17), as defined cytoarchitectonically, contains one complete representation of the contralateral visual field, termed V1, in which azimuth and elevation lines are approximately orthogonal. The upper visual field is represented caudally and the nasal field laterally. Binocular cells are encountered in the cortical representation of the nasal 30–40° of the visual field, and there is an expanded representation of the nasal field.Extrastriate visual cortex of the mouse, like that of other mammals, contains multiple representations of the visual field. The cytoarchitectonic region of cortex lateral and rostral to area 17, termed area 18a, contains at least two such representations. The more medial of these, which by convention we have called V2, is a narrow strip surrounding V1 on its lateral and rostral aspects; the vertical meridian lies along a portion of its common border with V1. The visual field representation in V2 is not a mirror image of that in V1; the representation of the horizontal meridian forms the lateral border of V2, and the visual field representation is split so that adjacent points on either side of the horizontal meridan are represented in nonadjacent parts of V2. The other visual field representation within area 18a, which we have termed V3, is a small but apparently complete representation that lies lateral to V2. The visual field representations medial to area 17 correspond to cytoarchitectonic area 18b. Area 18b contains two representations of the temporal visual field that we have labeled Vm‐r and Vm‐c, and contains little or no representation of the most nasal aspect of the field.
The organization of afferents to the lateral posterior nucleus in the golden hamster after different combinations of neonatal lesions
Authors: Crain Barbara J. , Hall William C. 
Published: January 2005

AbstractAfter a neonatal lesion of the ipsilateral superior colliculus, the projections to the lateral posterior nucleus from the contralateral superior colliculus and retina expand their terminal fields until they share a common border. In the first experiment described in this paper, we removed both superior colliculi at birth and used the Fink‐Heimer method to show that the optic tract projection could expand even further and enter the region which would have been occupied by the terminals of the crossed colliculus projection. Similarly, in the second experiment, we showed that the crossed collicular projection could be increased even more if the contralateral eye as well as the ipsilateral colliculus was removed at birth.Another result of a neonatal superior colliculus lesion is that the projection from the optic tract shares a border with the posterior neocortical projection. In the third experiment, we removed both the ipsilateral superior colliculus and the posterior neocortex at birth and demonstrated that the optic tract projection expanded more than after an ipsilateral colliculus lesion alone.Our results support the hypotheses that the projections from the ipsilateral and contralateral superior colliculi and the retina compete for synaptic space in the lateral posterior nucleus, and that a similar competition between the retinal and cortical projections may also occur.
Motor axon sprouting and site of synapse formation in intact innervated skeletal muscle of the frog
Authors: Rotshenker Shlomo , Reichert Fanny 
Published: January 2005

AbstractThe pattern of motor innervation to the cutaneous‐pectoris muscle of the frog is altered after injuring the motor nerve to the contralateral muscle in that muscle fibers innervated by a single motor nerve cell become polyneuronally innervated. This polyneuronal pattern of innervation was detected by single cell recordings of multiple end‐plate potentials from muscle fibers. The present study shows that the anatomical basis for this electrophysiological observation is the formation of new additional synapses by intact motor neurons on already innervated muscle fibers at new sites. Light and electron microscopical examination of muscles stained with Zinc Iodide and Osmium revealed that the sources for the new axon terminals were the intact motor axons and nerve endings that gave rise to sprouts that formed synaptic connections with muscle fibers apparently not innervated by their parent axons. Furthermore, new synapses were formed at new synaptic sites. The increased incidence of polyneuronal innervation that was detected electrophysiologically was associated, in the same muscles, with a proportional increase in the average end‐plate size estimated from the measurements of cholinesterase‐stained sites. Additional evidence that synapses were formed at new sites was that the shape of the different components of multiple end‐plate potentials in some polyneuronally innervated muscle fibers differed in their rise‐times. No such recordings were observed in polyneuronally innervated muscle fibers of normal frogs.
Substance P in the vagal sensory ganglia: Localization in cell bodies and pericellular arborizations
Authors: Katz David Miles , Karten Harvey J. 
Published: January 2005

AbstractThe distribution of Substance P‐like immunoreactivity in the jugular and nodose ganglia of rabbits and pigeons has been studied using immunocytochemical staining techniques. Substance P‐like immunoreactivity is localized to neuronal cell bodies and processes in the jugular and nodose ganglia, and to pericellular fiber plexi in the nodose ganglia of both species. The numbers and sizes of cells which exhibited Substance P‐like immunoreactivity in each ganglion were determined using quantitative morphometric techniques.The distribution of Substance P‐like immunoreactivity in the rabbit and pigeon vagal sensory ganglia is characterized by several general features. In most of the ganglia, immunoreactive neurons factor into discrete types which can be distinguished from one another, and from non‐immunoreactive neurons, by size. In addition, immunoreactive nodose and jugular ganglion cells, respectively, are distinguishable on the basis of size. Finally, a considerably higher percentage of immunoreactive neurons is found in the jugular ganglion than in the nodose ganglion.Substance P‐like immunoreactivity was also seen in pericellular fiber plexi which encircle individual neurons in the nodose ganglion of rabbits and pigeons. These plexi are composed of varicose fibers which appear to terminate as boutons on the surfaces of the cells which they encircle.The distribution of Substance P‐like immunoreactivity within the vagal sensory ganglia is discussed with respect to the possible peripheral targets and functions of Substance P‐containing vagal afferents. Our findings suggest that Substance P‐containing vagal sensory neurons are involved in a variety of visceral and somatic afferent functions.
The early development of the nervous system in staged insectivore and primate embryos
Authors: Müller F. , O'Rahilly R. 
Published: January 2005

AbstractThe early development of the nervous system was studied in staged embryos of Hemicentetes semispinosus, Microcebus murinus, Alouatta seniculus, Cebus appella, Cebus albifrons, Macaca mulatta, and Homo sapiens. The specimens were assigned to Carnegie stages 11–13. Serial transverse sections were examined and graphic reconstructions were prepared. The early development of the neural tube is basically similar in all the species investigated but differences in detail are noticeable. The mesencephalic flexure serves in all cases as a landmark for Malpighi's tripartite subdivision of the brain. The nonhuman embryos seem to show a little more variation than the human in the closure of the neuropores in relation to somitic count. With the exception of the later‐appearing terminal‐vomeronasal component, all major portions of the neural crest as classified by O'Rahilly ('65) are represented in both the nonhuman and the human embryos studied. No crest is present at the level of rhombomere 1, nor at rhombomere 3 except in the platyrrhines and some human embryos, nor at rhombomere 5 except in certain human specimens. An indication of the division of the trigeminal ganglion into its primary divisions is rare at stage 11 (C. apella), may be visible at stage 12 (Alouatta, Macaca, Homo), and is definite (in Homo) at stage 13. Ganglionic contributions from head ectoderm (epipharyngeal placodes), as previously described in the human and some other vertebrate embryos, were sought and found in Cebus apella. In both nonhuman and human, a tendency is noted whereby the rostral limit of the occipitospinal crest, high at stage 11, seems to descend relatively at stage 12, and ascend again at stage 13 (at least in the human) to become associated with the appearance of the accessory and hypoglossal nerves. In general, the motor components of the nerves are identifiable before the sensory elements, and, in the present study, nerve fibers were first observed in the human at stage 13 in some of the cranial nerves and in the ventral roots of the spinal nerves.
Propriospinal fibers interconnecting the spinal enlargements in some quadrupedal reptiles
Authors: Kusuma A. , ten Donkelaar H. J. 
Published: January 2005

AbstractThe cells of origin, course and site of termination of long propriospinal fibers interconnecting the intumescences have been studied with the aid of the horseradish peroxidase technique, as well as with anterograde degeneration techniques, in some quadrupedal reptiles (the lizards Tupinambis nigropunctatus and Varanus exanthematicus, and the turtles Testudo hermanni and Pseudemys scripta elegans). The anterograde degeneration findings suggest that long descending propriospinal fibers from the cervical intumescence are distributed bilaterally to the ventral gray of the lumbar enlargement, including the lateral motoneuron column. Long ascending fibers from the lumbar to the cervical intumescence are distributed, also bilaterally, to the ventromedial part of area VII–VIII. The cells of origin of long descending propriospinal fibers were found in the medial part of area VII–VIII in the cervical intumescence, particularly contralateral to the injection side. The cells of origin of long ascending propriospinal fibers were found in the lumbar intumescence, also particularly contralateral to the injection side, in the ventromedial part of area VII–VIII. It seems likely that in the reptiles studied the long propriospinal fibers interconnecting the spinal enlargements are in large part organized as crossed connections.The demonstration of long propriospinal fibers in lizards and turtles—i.e. quadrupedal reptiles that move their limbs in a particular diagonal pattern—suggests that these pathways are of great importance for the coordination of forelimb and hindlimb movements.
Effects of undernutrition on gliogenesis and glial maturation in rat corpus callosum
Authors: Lai Mabel , Lewis Paul D. , Patel Ambrish J. 
Published: January 2005

AbstractRats were undernourished by halving the mother's food intake from the sixth day of pregnancy onwards and through lactation. At weaning, the young rats were restricted to half the normal weight of food. A combination of light and electron microscopic techniques was used to study the effects of this regime on gliogenesis and glial maturation in the corpus callosum of animals aged between 15 and 48 days.A disturbance of neuroglial proliferation was suggested by the finding of an increased proportion of astroglia relative to oligodendroglia in the 15‐day‐old undernourished rats, indicating a delay in the acquisition of cells produced relatively late in development. Impaired differentiation of oligodendroglia was suggested by the finding in treated animals of increased light oligodendrocytes at 15 days and a deficit of dark oligodendrocytes at 48 days, relative to controls. The previously observed retardation in myelin acquisition seems thus to be related to a dealy in the differentiation of oligodendroglia, although it seems likely that the proliferation of these cells is also disturbed in undernutrition.