bluuebunny/crossref_metadata_2025_split huggingface dataset:
The projection of optic fibers to the visual centers in the cat
Authors: Laties Alan M. , Sprague James M. 
Published: January 2005

AbstractRetinal projections to the thalamus and midbrain were studied by the Nauta‐Laidlaw technique. After unilateral enucleation, degeneration was found in five areas: dorsal lateral geniculate nucleus (LGNd, thalamus), ventral lateral geniculate nucleus (LGNv, subthalamus), nucleus of optic tract (NOT, pretectum), superior colliculus (S.C., tectum), and accessory optic nuclei (AON, tegmentum). Degeneration after focal lesions in nasal retina made by photocoagulation is found in four areas of the contralateral LGNd: Laminae A and B, nucleus interlaminaris centralis (NIC), and the medial part of nucleus interlaminaris medialis (NIM). Temporal lesions lead to degeneration ipsilaterally in three areas: lamina A1, NIC, and the lateral part of NIM. Central lesions are followed by bilateral projections; the area of degeneration on each side is greater than that of peripheral lesions of comparable size. Focal degeneration is found in NIM after either central or peripheral retinal lesions. Each retina projects to both NOT and both S.C. In NOT, degeneration following nasal lesions is strictly contralateral while after temporal lesions is mainly ipsilateral. A bilateral projection of temporal retina to NOT constitutes an exception to theories of chiasmal decussation. Both nasal and temporal projections to AON are wholly crossed, thus constituting another example of projection of temporal retina to the contralateral side, Nasal fibers project contralaterally and nearly all temporal fibers ipsilaterally to S.C.
Sprouting of optic tract projections in the brain stem of the rat
Authors: Goodman Donald C. , Horel James A. 
Published: January 2005

AbstractThe present experiments examine axonal sprouting of optic tract projections as a consequence of occipital cortex removal. Eyes were removed bilaterally in experimental rats 16 months following unilateral occipital cortex ablation. Seven animals survived this procedure. Controls included rats sacrificed 16 months after unilateral occipital cortex ablation, one week after unilateral occipital cortex destruction, and one week after bilateral or unilateral eye removal. Brains were serial‐sectioned and stained by the Nauta‐Gygax method for degenerating axons.Sprouting occurred only at two loci, the caudal half of the ventral lateral geniculate nucleus, pars lateralis, and the caudal portion of lateral nucleus of the optic tract and subjacent medial quarter of pretectal nucleus. These loci have in common that they are regions of convergence in a major fashion of the two fiber systems, the occipitofugal and retinofugal projections on which experiments were done. However, sprouting did not occur in other similarly deafferented regions. Explanations for this specificity of sprouting are discussed.Optic tract sprouting was observed only at paraterminal portions of the axon and not as collateral sprouts along its course.A suggested relationship between axonal sprouting and functional plasticity is discussed.
Fiber degeneration after lateral hypothalamic lesions in the rat
Authors: Wolf George , Sutin Jerome 
Published: January 2005

AbstractFiber degeneration in the rat following lesions of the lateral hypothalamic area was studied by the method of Nauta and Gygax ('54). Ascending degeneration in the medial forebrain bundle enters the preoptic area and the medial and fimbrial nuclei of the septum. Less dense degeneration is found in the lateral septal nucleus and a few fibers bypass the septum and reach the cingulate cortex. Descending degeneration in the medial forebrain bundle enters the ventral tegmental area of Tsai giving off a few fibers to the mammillary bodies on the way. In the midbrain fibers turn dorsomedially to enter the raphe nuclei and the central gray and dorsolaterally to enter the nucleus mesencephalicus profundus pars lateralis. A small group of fibers leaves the anterior part of the lateral hypothalamus in a dorsomedial direction and passes through the inferior thalamic peduncle and stria medullaris to enter the lateral habenular nucleus. Another bundle leaves the posterior part of lateral hypothalamus in a dorsomedial direction and passes through the posterior midline thalamus to enter the central gray. No degeneration was found in the ventromedial hypothalamus in rats with lateral hypothalamic lesions. Our ability to stain fine degenerating fibers in this region was demonstrated in rats with medial hypothalamic lesions.
The postnatal development of neocortical neurons in the dog
Authors: Fox Michael W. , Inman Ottilie R. , Himwich Williamina A. 
Published: January 2005

AbstractExaminations were made by means of the Golgi‐Cox method of the developing neuronal elements of the cortex of the dog during the first ten weeks of life. The neuronal elements undergo gradual morphological differentiation during the first week. From 2–4 weeks of age the most dramatic changes in the development of dendritic arborizations occur. After this time the changes are slower with terminal maturation of cellular elements, cessation of neuronal growth and final organization of apical and basilar dendrites and their collaterals. Comparison with the development of the kitten shows close similarity in the development of canine and feline neocortex. In dogs, however, an essentially mature neocortex is not reached until after four weeks of age. The relation of these data to biochemical and electrophysiological development and behavioral patterns in the young dog is discussed.
Degeneration of some intralaminar thalamic nuclei after cortical removals in the cat
Authors: Murray Marion 
Published: January 2005

Abstract
The projections of the central medial, paracentral, and central lateral nuclei of the cat have been studied by the method of retrograde degeneration.
Following removal of neocortex, with preservation of rhinencephalic and sub‐cortical structures, the central medial, paracentral, and central lateral nuclei degenerate severely.
The central medial and paracentral nuclei degenerate only after extensive cortical lesions which include limbic cortex. There is evidence of a topographical organization of the projection since rostral sectors of central medial and paracentral nuclei show cell loss after lesions involving anterior limbic and orbitofrontal cortex while caudal sectors degenerate after lesions involving cingulate and parieto‐occipital cortex.
The central lateral nucleus projects to cortex of the parieto‐occipital region.
Some findings are considered which indicate that fibers from the central medial, paracentral, and central lateral nuclei travel rostrally to the region of the head of the caudate nucleus before turning caudally to distribute to cortical areas.
Descending hypothalamic medullary pathways in the cat
Authors: Cheatham Melvin L. , Matzke Howard A. 
Published: January 2005

AbstractPosterior hypothalamic electrocoagulative lesions were stereotaxically placed in 20 cats. The resulting degenerating pathways to the medullary centers were studied using the Nauta technique. The size of the lesions was less than 1 mm in diameter. The resulting degeneration did not conform to a discrete pathway but passed in a diffuse manner into the brainstem reticular formation. In the lower medulla the degenerating axons appeared to become more concentrated in the dorso‐lateral visceral gray in close association with the dorsal motor nuclei of X. Pre‐terminal axons were noted adjacent to large and medium sized neurons in this area. A progressive decrease in degenerating fibers was apparent below this level. A small number of degenerating axons could be identified in the lateral reticular process of the central gray matter at the level of C2.
Projections from the fornix to the hippocampal formation in the squirrel monkey
Authors: DeVito June Logan , White Lowell Elmond 
Published: January 2005

AbstractIn six squirrel monkeys, lesions involving the septum and fornix were made during aseptic operations. After postoperative survival periods ranging from 9 to 22 days, the animals were sacrificed under anesthesia by intracardiac perfusion of 10% formalin. The brains were sectioned and stained with the Nauta method for demonstrating degenerating axis cylinders. Degenerating fibers were traced from the fimbria into the hippocampal formation. Although degenerating fibers were present in all regions of the hippocampal formation, the main sites of degeneration were the hilus of the fascia dentata; the strata oriens, pyramidale and radiatum of the cornu ammonis; the caudal presubiculum; the parasubiculum and the entorhinal area.
The microscopic anatomy and ulrastructure of the nervous system in the earthworm (Lumbricus sp.) with emphasis on the relationship between glial cells and neurons
Authors: Levi Joe U. , Cowden Ronald R. , Collins George H. 
Published: January 2005

AbstractSubesophageal ganglia and the first four ventral chain ganglia from earthworms of the genus Lumbricus were examined by light and electron microscopy. Trypan blue injections indicated that this substance does not pass beyond the cord sheath. Tritiated isoleucine displayed a general non‐neuronal distribution after one‐half hour exposure but the amino acid was progressively concentrated in neurons at 1 and 2 hours. Ultrastructural studies indicated that a form of cytoplasmic inclusion was common to glial cells and neurons, and that a similar type material was present extracellularly in the cord sheath. Three distinct variations of glial cytoplasm were recognized at the ultrastructural level, and these appeared to be conditioned by the location of the glial cell in the nervous system. A sequence of morphology was observed which suggests that glial cells in the earthworm transport material from the cord sheath to the neurons. The glia directly associated with neurons sent a number of invaginating processes into the neuron which may from the anatomical basis for exchange of materials.
The lumbar, sacral and coccygeal tactile dermatomes of the dog
Authors: Fletcher Thomas F. , Kitchell Ralph L. 
Published: January 2005

AbstractTactile dermatomes L1 through Co5 were determined in the dog by electrophysiological recording. All dermatomes were continuous skin fields which extended from the dorsal to the ventral midlines and displayed considerable cranio‐caudal overlap. Most cutaneous regions were innervated by three dorsal roots, although some loci were supplied by two or four segments.The dermatomes boundaries, which were determined in relation to palpable skeltal landmarks, displayed an inherent variability from subject to subject, around a most common distribution. This variability was limited to the distance of one vertebral spine, cranial or caudal to the mode boundaries.Dermatomes exhibited central regions of maximal innervation where the response per rootlet appeared greater than at the periphery. The central‐peripheral sensitivity distinction was more remarkable in the limb dermatomes where proprioceptive afferents decreased tactile resolution at the periphery of the field. The maximal innervation zones appeared to approximate the locations of the major cutaneous nerves. The experimental findings suggest the hypothesis that the afferent fibers comprising a canine dorsal root are intermixed in the spinal nerve and are distributed at random within the dermatome.
Autoradiographic and histological studies of postnatal neurogenesis. II. A longitudinal investigation of the kinetics, migration and transformation of cells incorporating tritiated thymidine in infant rats, with special reference to postnatal neurogenesis in some brain regions
Authors: Altman Joseph 
Published: January 2005

AbstractThymidine‐H3 was injected intraperitoneally into 6‐ and 13‐day old rats and they lived afterwards for periods ranging from one hour to 60 days. Autoradiographic data obtained from animals surviving for short periods were used to estimate rates of regional cell proliferation. Animals with longer survival were used to deduce the movements of new cells from germinal sites, through migratory channels, to target areas, and to determine their mode of differentiation.The formation and differentiation of microneurons goes on during infancy, though in most structures at a declining rate. In the wall of the olfactory ventricle cell multiplication continued at a high rate at six days, with a decline at 13 days, and the new cells migrated to the layers of the olfactory bulb. The migration of labeled cells from the lateral ventricle was traced, by way of the fimbria, to the polymorph cell layer of the dentate gyrus, and from there to the granular layer. The “older” granule cells were located in the upper part of the granular layer, the “younger” cells at its base. Cell multiplication continued at a very high rate in the external granular layer of the cerebellar cortex, whence cells migrated to the molecular layer and internal granular layer. Speed of migration was approximately 50 μU/day in the olfactory bulb, and 60–70 μ/day in the cerebellum. The possible significance of these findings was discussed.
A functional and histochemical characterization of motor units in a heterogeneous muscle (flexor digitorum longus) of the cat
Authors: Olson Camille B. , Swett Chester P. 
Published: January 2005

AbstractThis paper reports an attempt to differentiate motor units of several types both physiologically and histochemically.The average characteristics of the motor units in the flexor digitorum longus (FDL), flexor hallucis longus (FHL) and soleus muscles of cats with one chronically deafferented hind limb were studied. The average maximal tension per motor unit was calculated to be 14.5 g for FDL, 25.8 g for FHL and 19.7 g for soleus. In general, the average size of the motor units in each muscle increased with the weight of the animal. The total number of motor units to each muscle and the diameters of all efferent nerve fibers were determined in histological cross‐sections of the deafferented nerve.The FDL muscle was selected for study of individual units isolated from the ventral roots of 15 cats. The conduction velocities of 108 axons ranged from 71.3 to 114.3 m/sec. These units developed maximal isometric tensions ranging from 0.4 to 100.0 g, with an average of 9.6 g. The frequency distribution of maximal tensions was markedly skewed, with 83 units developing less than 10 g. The twitch tensions of 90 units averaged 0.9 g, with a range of 0.1 to 10.0 g. All units in which no twitch was detected developed less than 5 g of maximal tension. The small size of the units and the limitations of the equipment were thought responsible for the occasional failure to record a twitch. The contraction times of 85 units fell between 13 and 81 msec, with a modal class of 30 to 35 msec. During continuous stimulation at 100/sec, large units usually proved more susceptible to fatigue than small units. Regression analyses of conduction velocity versus maximal tetanic tension revealed that large units (> 19 g) belonged to a different population than units developing less than 19 g of maximal tension. In addition, the findings suggest that small units may perhaps be divided into a slow and fast group according to their contraction times.Mitochondrial adenosine triphosphatase activity was demonstrated in cross‐sections of FDL muscle fibers. A correlation between histochemically distinguishable fiber types and functionally distinguishable motor units is proposed.
The development of hippocampal and dorsolateral pallial regions of the cerebral hemisphere in fetal rabbits. I. Fifteen millimeter stage, spongioblast morphology
Authors: Stensaas Larry J. 
Published: January 2005

AbstractThe structure of the cerebral hemisphere of 15 mm rabbit embryos was studied with aniline and Golgi stains. Three layers of successively less denselypacked cells were identified in aniline stained sections–matrix, intermediate, and marginal laminae.In the matrix lamina two types of cells were identified in Golgi impregnations:(1) neuroblasts with axons ascending to the intermediate and marginal laminae, (2) spongioblasts attached to the ventricular surface by a short proximal process. Two varieties of spongioblasts can be distinguished according to the mode of termination of long distal processes: (1) typical spongioblasts with claviform enlargements terminating at the pial surface, (2) freely‐arborizing spongioblasts with multiple short processes arborizing in the intermediate and marginal laminae.The terminal arbors of freely arborizing spongioblasts, here recognized for the first time, may represent either the growing processes of immature spongioblasts destined to reach the pial surface, or an apparatus having special relations to the embryonic vessels and nerve processes.In the intermediate lamina, pyramidal cells outline the plan of the cortex and subcortical white matter. They have apical dendrites that ascend and ramify in the marginal lamina and axons which descend and turn toward the base of the hemisphere. Neurons with ascending axons are also present, and elements with horizontal axons are located in both the marginal and intermediate laminae.
Degeneration of the presynaptic terminals (boutons) in the spinal cord of the cat after rhizotomy
Authors: Von Mihálik Peter 
Published: January 2005

AbstractThe degeneration of the boutons, following rhizotomy of the C2 roots, has been studied in cats' spinal cords fixed in Susa and stained by albumin‐silver impregnation on slides (Mihálik, '50).It was found that, three days after the lesion, large rosette shaped argyrophilic structures appeared around the nerve cells and their dendrites. These structures disappeared the fourth day.It was concluded that the presynaptic end‐branches of the severed postior root fibers do not undergo a granular degeneration in situ but first retract and metamorphose into “rosettes” and then disappear by further degeneration and absorbtion. This rosette forming is considered to be an agony reaction at the terminals of the severed posterior root fibers, and it is considered to be homologous to the metamorphic agony reaction (at the stump of the amputated part of the peripheral nerves) described by Cajal.
Mitotic division of neuroglia in the normal adult rat
Authors: Hommes Otto R. , Leblond C. P. 
Published: January 2005

AbstractTwenty‐four adult rats were given an injection of 3H‐thymidine at 4.00 p.m. and sacrificed two at a time everyhour for the next 12 hours. Another 24 adult rats were similarly treated but after inejction at 4.00 a.m. The brainswere fixed by immersion in Bouin fluid. Sections were stained with hematoxylin‐eosin and radioautographed. In another experiment two animals were sacrificed two and nine hours respectively after 3H‐thymidine injection and the brains were fixed in formalin. The sections were stained by silver impregnation and radioautographed.One hour after 3H‐thymidine injection, a number of glial nuclei were labeled: all were in intrphase. By 2–3 hours, labeled mitotic figures appeared and increased in number with time. From 4–5 hours after injection on, pairs of labeled nuclei were seen in increasing numbers. This sequence of events, which was observed with slight differences in the two main groups, indicated that labeled glia nuclei go through mitotic division.It is concluded that a low degree of mitotic activity continually takes place in the glial population of adult rats. About one fifth of the divisions seem to be in microglia. Most of the others seem to occur in cells of the oligodendrocyte family.
Motor function and the corticospinal tracts in the dog and raccoon
Authors: Buxton Donald F. , Goodman Donald C. 
Published: January 2005

AbstractFollowing unilateral somatomotor cerebral cortex ablation in three raccoons and ten Beagle dogs similar functional deficits of hypotonia, hypokinesia and dysmetria limited to the side opposite the lesion were observed in both species. Only in the raccoon was a loss of digital manipulative ability of the contralateral forepaw observed.The Nauta‐Gygax method was used to trace corticospinal projections into the grey matter of the spinal cord. In both species preterminal degeneration was found ipsilaterally and contralaterally in Rexed's laminae V, VI, VII and VIII. Furthermore, in the raccoon preterminal corticospinal degeneration was followed into the dorsal portion of contralateral lamina IX at the level C7–8. Although direct corticospinal projections to motoneurones of lamina IX occur in greater quantity and in increasing quantity with increasing complexity of digital abilities among the primate species, it appears that such connections are not limited phylogenetically to primates and probably are correlated with the ability of a species to manipulate the digits.Comparison of these anatomical findings with those reported for the cat revealed a progressive ventral shift of corticospinal terminations in ventral horn neuronal groups from cat to dog to raccoon, specifically into lamina IX in the raccoon. No single pattern of corticospinal terminations appears typical for the Order Carnivora.Data on dogs varying in age from one month to adult support the suggestion that there is a direct correlation between some motor cortex functions and postnatal maturation of corticospinal connections.
Cortical projections to the lower brain stem and spinal cord in the tree shrew (Tupaia glis)
Authors: Shriver Joyce E. , Noback Charles R. 
Published: January 2005

AbstractA study was made of corticofugal projections to the lower brain stem and spinal cord in the tree shrew (Tupaia glis). Degeneration resulting from selective ablations of the motor, sensory and frontal cortex in ten animals was studied by the Nauta technique. Following ablations of motor and sensory cortex degeneration was found bilaterally: (1) throughout the rostrocaudal extent of the lateral reticular formation, (2) in all trigeminal sensory nuclei and, (3) in the dorsal column nuclei (contralateral predominance). All three cortical areas projected fibers to the ipsilateral pontine nuclei and bilaterally to the medial reticular formation (ipsilateral predominance). Fibers from the motor cortex were distributed throughout the medial reticular formation; fibers from sensory and frontal cortex were distributed to selective regions of the medial reticular formation. The majority of corticospinal fibers decussated and descended to lower cervical (frontal fibers) and lower thoracic (motor and sensory fibers) levels. The small uncrossed component descended in the ipsilateral dorsal funiculus only throughout cervical segments. Corticospinal degeneration terminated primarily in the internal basilar region (medial half of lamina VI), medial aspect of the neck (lamina V) and, to a lesser extent, in the head (laminae III and IV) of the dorsal horn. Relatively few fibers projected to the zona intermedia (lamina VII) and no terminations were present in the motor nuclei (lamina IX) of the spinal nerves.