bluuebunny/crossref_metadata_2025_split huggingface dataset:
Epibranchial and lateral line placodes of the cranial ganglia in the gecko, Gymnodactylus kotschyi
Authors: Thomas Evans Llewellyn 
Published: January 2005

AbstractA study of both the epibranchial and the lateral line placodes in forty‐six embryos of Gymnodactylus kotschyi was carried out with a fairly continuous series of embryos, ranging from the first day of incubation to hatching. The findings were reported:

The opthalmic placode of the V, from stage 14 to 23, was found in 16 embryos out of 24 and in 1 embryo of stage 24.
The maxillo‐mandibular placode of the V was found in 15 embroys out of 31 between stages 17 and 26.
The epibranchial placode of the VII was found in 29 out of 31 embroys between stages 14 and 26.
The extrapyramidal systems of the spinal cord: Results of combined spinal and cortical lesions in the macaque
Authors: Goldberger Michael E. 
Published: January 2005

AbstractIn order to study the contribution of the extrapyramidal systems of the spinal cord to the control of tone and movement of skeletal muscle, lesions were made in the ventral half of the spinal cord in four macaques. Ablation of area 4 of the contralateral cerebral cortex was added in three animals several months later. Comparisons of neurological examinations performed (a) preoperatively, (b) following cord lesions, and (c) following combined spinal and cortical lesions led to the following conclusions: (1) spinal lesions resulted in increased resistance to passive movements which may have contributed to the loathness to move and inability to perform some movements that also followed these lesions: (2) return of motor function following cortical ablation appeared to depend upon the integrity of the spinal extrapyramidal tracts: (3) spasticity which had resulted from loss of extrapyramidal tracts was enhanced by subsequent loss of cortical area 4 even when all known inhibitory spinal pathways were already severed. Alternative mechanisms for transmission of cortically initiated inhibition to the cord are discussed and it is suggested that the manner in which the extrapyramidal systems function may not be rigid in the affected animal.
The mammalian pons, olive and pyramid
Authors: Marsden C. D. , Rowland R. 
Published: January 2005

AbstractThe evolution of the pons, olive and pyramid have been studied in a series of mammals. The pons in the Monotremata is post‐trigeminal. In Marsupialia and most species of lower Eutherian orders, the pons is pre‐trigeminal and relatively constant in size and simple in form. In the Primates it undergoes a remarkable increase in size, and progressively extends caudally to cover the corpus trapezoideum. The pons in the giant anteater, hippopotamus, rhinoceros, elephant, bear, otter, Pinnipedia and Cetacea is unusually well developed.The olive is not visible in the Monotremata and Marsupialia. In the Eutheria it is seen only in the Carnivora, Cetacea, elephant and Primates. The olive in the elephant, bear, otter, Pinnipedia and Cetacea is unusually prominent.The pyramids show the same evolutionary trends as the pons, except in the Artiodactyla, Perissodactyla, Proboscides, Pinnipedia, otter and Cetacea where they are unusually small.The size and form of the pons, olive and pyramid are in keeping with the development of the cerebral cortex,1 basal ganglia and cerebellum. These structures increase in size and complexity, achieving their maximum development in man. Their relative sizes indicate the functional significance of the cortico‐pontine, striatopontine and pyramidal pathways to that animal. Variations from the well‐defined pattern of evolution of these structures in mammals may be correlated with specific adaptations of individual species to terrestial and aquatic life.
Efferent connections of the supra‐geniculate nucleus in the Albino rat
Authors: Fortuyn J. Droogleever , Minderhoud J. M. 
Published: January 2005

AbstractUsing the experimental method of retrograde cell degeneration efferent connections of the supra‐geniculate nucleus to the caudal part of the ipsilateral putamen were demonstrated in rats. Following lesions in the cortex, rostral putamen and caudate nucleus the supra‐geniculate nucleus remains intact, but following lesions in the caudal part of the putamen this nucleus shows retrograde cell degeneration.The supra‐geniculate nucleus belongs to the intermediate nuclei of the thalamus, where it constitutes the caudal part. The connections suggest that this nucleus contributes in some way to opto‐motor or auditivo‐motor functions.
Organization of the first and the second somesthetic regions (SI and SII) in the rat thalamus
Authors: Emmers Raimond 
Published: January 2005

AbstractOrganization of the rat somesthetic thalamus was studied by a combination of electrophysiologic, stereotaxic, and histologic methods. A monopolar recording electrode was inserted numerous times in any one preparation to explore systemically those thalamic regions which receive somesthetic input. The tip of the electrode was small enough to detect unit activity as well as slow potentials. The recording sites were spaced at 250 and 300 μ distances by using sensitive microdrives in all stereotaxic dimensions. For each recording sire maps were made of the peripheral projection fields which, upon tactile stimulation, evoked strong, medium strong, or weak responses. Punctures made by the recording electrode were reconstructed from sections cut by the freezing method and the geometric arrangement of the recording sites within the thalamus was reconstituted.Two thalamic regions for somesthetic projection (SI and SII) were found in the rat thalamus. They are similar to the first and the second somesthetic areas previously described with the rat cerebral cortex. The thalamic regions encompass the ventrobasal nuclear complex. In the relatively large region of SI there is contralateral projection of the body only. The snout is extensively represented througout this projction region whereas the hindquarters project on a smaller amount of thalamic tissue found in the extreme anterolateral position of SI. Region SII is relatively small. It is situated posterolaterally to SI. The animal's body is represented anew but this time bilaterally; snout dorsomedially, hindquarters ventrolaterally.
The projection of afferent pathways on the thalamus of the rat
Authors: Davidson Neil 
Published: January 2005

AbstractElectrophysiological techniques have confirmed that, except for differences in topographical organization, the projection of afferent pathways upon the thalamus of the rat is very similar to that found in higher mammals such as the rabbit, cat and monkey. Recording of evoked potentials has revealed a predominantly contralateral projection upon the ventrobasal complex, with an extensive snout region medially, foreleg representation ventromedially and hindleg and tail in a small lateral strip. There is a large bilateral projection of afferent pathways on the posterior thalamus—an area caudal to and partially co‐extensive with the ventrobasal complex and medial to the medial geniculate body. The only sign of topographical organization in this area is a somewhat lateral representation of hindlegs and tail.
Learning and the dorsal basal lobe in the Octopus
Authors: Parriss J. R. 
Published: January 2005

AbstractLesions were made in the dorsal basal lobe of the Octopus. The size and the region of these lesions were related to the animals' capacity to learn a simple visual discrimination and to the level of attack maintained during training. No significant relationship was found between the discrimination scores and the size of the lesion but there was evidence that the position of the lesion influenced discrimination.
Development of the XIth or spinal accessory nerve in the chick. With some notes on the hypoglossal and upper cervical nerves
Authors: Rogers K. T. 
Published: January 2005

AbstractBodian stained serial sections show that N. XI first appears at Stage 19. By Stage 21 there are at least 350 rootlet fibers, and about 65 fibers have reached N. X in their growth. N. XI merges with the second cervical ganglion posteriorly, and passes through the first cervical ganglion while the latter is present. Contrary to findings from gross dissection, histological sections show that the second cervical ganglion is retained in the adult, and N. XI retains its relation to this ganglion. Nerve cells present along N. XI in the embryo disappear by adulthood from a little anterior to ganglion C. 2 to the most anterior levels of C. 1, possibly migrating along the nerve rather than degenerating. Proprioceptice fibers for the nerve may originate from cells that lie in the adult in or near the ganglion of C. 2 or in or near the jugular ganglion. Motor fibers originate from cells of the ventral horn of C. 2, C. 1, and the lowest medullary levels, and leave the cord and medulla by a route similar to the fibers of von Lenhossék of more posterior levels. N. XI in the adult contains about 350 spinal and 215 medullary fibers. The two main roots of N. XII on each side send strong lateral branches to the cervical musculature before joining to form the nerve to the tongue, to which C. 1 and C. 2 ventral roots also contribute.
Quantitative determinations of neurons and glial cells in the nuclei of the facial and vestibular nerves in man, monkey and dog
Authors: Blinkov S. M. , Ponomarev V. S. 
Published: January 2005

AbstractThe number of Neurons and the Neuronal and glial density per volume of the facial and the vestibural nuclei in two brain stems on each side in man, monkey and dog were counted. The average number of Neurons in the facial nucleus in man (12,500) is greater than in the monkey (4,600), but lower than in the dog (15,800). On the contrary, in the vestibural nuclei the total number of Neurons in man (245,00) is greater than in the monkey (143,000) as in the dog (134,000). The Neuronal density varies considerably in different nucei and different species of animals. At the same time, the glial density is much more even. In all the nuclei the glial density is highest in the dog, lower in the monkey and still lower in man.
Flexor rigidity
Authors: Mettler Fred A. 
Published: January 2005

AbstractUpper limb flexor postures have frequently been described as part of the consequences of primate decortication, when such animals are placed in the vertical instead of horizontal position. Flexor postures have also been said by D. Denny Brown to occur following bilateral section of the eighth cranial nerve. In the present communication a pattern of alternating flexor postures (contralateral forelimb and ipsilateral hindlimb flexion with extension and magnet reaction in the ipsilateral forelimb and contralateral hindlimb) is described after postcollicular mesencephalic hemisection. In addition, quadriflexion (flexion of all four extremities) is described following midline section of the cerebrum and mesencephalon by a cut which, commencing with, and including, the supramammillary decussation extends back far enough to include the decussation of the brachium conjunctivum. In these experiments the optic chiasm, anterior commissure and rostral two thirds of the corpus callosum have not been cut, Severance of. the decussation of the brachium conjunctivum does not appear to be a determinative factor in the resultant flexor posture.
Filamentous and tubular structures in mammalian axoplasm. An electron microscopic study,
Authors: Cravioto Humberto 
Published: January 2005

AbstractA neurofibrillar and neurotubular ultrastructure of mammalian axoplasm has been observed consistently after glutaraldehyde fixation. The embedding media (Epon, Maraglas, Vestopal W, Araldite), dehydration procedure (alcohol, acetone) and counter‐strain used (lead citrate, uranyl acetate, phosphotungstic acid) played no significant role in the selective demonstration of neurotubules or neurofibrils. It was suggested that the neurotubules may form part of the neurofibrillar apparatus described by Cajal.
An electron microscopic study of the choroid plexuses of necturus maculosus
Authors: Carpenter S. J. 
Published: January 2005

AbstractThe choroid plexuses of the neotenous salamander, Necturus maculosus, were examined by light and electron microscopy. Their epithelium was found to consist of a single layer of flattened to cuboidal cells resting upon a well‐developed, continuous basement membrane. The cytoplasm of a typical epithelial cell contained, besides a large, centrally‐placed nucleus, numerous mitochondria, an extensive agranular endoplasinic reticulum, prominent Golgi complexes and a variety of dense bodies. In addition, occasional clusters of ribosomes, lipid droplets, fascicles of fine filaments and numerous glycogen granules were present within the cytoplasm. Specializations of the apical (ventricular) surfaces of the epithelial cells included an irregular brush border, cilia, and minute, possibly micropinocytotic, invaginations of the plasma membrane. Surfaces of contacts between epithelial cells were specialized by “tight junctions” desmosomes, and complex inter dictations of the apposed plasma membranes. The interstitial space separating the epithelial layer from the thin‐walled, non‐fenestrated plexus blood vessels contained a mesh‐work of collagen fibrils and a variety of connective tissue cell types. Electron dense Thorotrast particles were found to traverse the endothelial walls of the blood vessels and accumulate within the interstitial spaces within 30 minutes after being injected into the blood stream. The epithelial basement membrane, however, apparently prevented the tracer particles from reaching the epithelial cells, and the ventricular spaces beyond, as long as five hours after injection.
Degeneration time for optimal staining by Nauta technique. A study on transected vagal fibers of the cat
Authors: Warren Cottle Merva K. , Mitchell Robert 
Published: January 2005

AbstractCervical and abdominal vagus nerves taken at various survival times, (1–16 days following transections) have been stained with the Nauta technique and a modification of this technique, as well as with other stains commonly used to demonstrate Wallerian degeneration in peripheral nerve. Counts of the myelinated fibers were made on transverse sections of the osmium‐stained cervical vagus to furnish a measure of the rate of disappearance of the fibers. Approximately half of the myelinated fibers had disappeared in seven days and all were gone at 14 days. Fragmented axons in the cervical and abdominal vagi were demonstrated as early as three days and remained observable at seven days with the Nauta stain. In the abdominal vagus evidence of degeneration had disappeared by 11 days. In the cervical vagus, however, although only occasional axonal fragmentation was evident at 16‐days survival time large globules of myelin debris still persisted in the larger fibers.Unlike the CNS, fragmented axons persist for relatively short periods in the PNS and particularly in the small and unmyelinated fibers the survival time which allows demonstration of axonal fragmentation is critical.
Thalamic connections to insular and opercular cortex of monkey
Authors: Locke Simenon 
Published: January 2005

AbstractSubpial resection of insular and opercular cortex was performed in ten hemispheres of six macaque monkeys. Retrograde degeneration was studied in myelin and cresyl violet stained serial sections of whole brain specimens follwing survival of 12 to 15 months. Lesions restricted to teh insula, effectively sparing the orelying opercula, caused no retrograde degenration in thalamus. Specifically, nucleus ventralis anterior, nucleus ventralis posteromedialis pars parvocelluliaris, and nucleus ventralis posterior inferior were normal. Lesions which involved orbitofrontal cortex produced the expected degeneration of the ventral division of paralamellar nucleus medialis dorsalis (medialis dorsalis pars multiformis). Surprisingly, minimal but unequivocal degeneration was seen in this nucleus when lesiions were restricted to the superior temporal plane; it was more marked when the parietal operculum was included in the lesion. With destruction of the white matter of the parietal or frontal operculum, degeneration was apparent surrounding the centrum medianum, most conspicuously in ventral paralamellar medialis dorsalis and parvocelular nucleus ventralis posteromedialis. Increased gliosis without nerve cell destruction in the basomedial part of nucleus ventralis anterior was present in two specimens with anterior insular ablatioins presumably as the result of interruption of cortico‐thalamic projections from orbitofrontal cortex.
Afferent connections to neocortex in the opossum (Didelphis virginiana)
Authors: Ebner Ford F. 
Published: January 2005

AbstractAfferent axons to the opossum's neocortex were carefully traced to their areas of termination using the Nauta‐Gygax silver technique for degenerating axons. The two major systems of incoming fibers arise primarily from contralateral neocortex (commissural fibes), and ipsilateral thalamus (thalamocortical fibers).Following complete transection of the anterior commissure‐corpus callosum amalgam, degenerating fibers could be traced to almost all areas of neocortex. The same pattern resulted from total removal of neocortex from one cerebral hemisphere. Commissural fibers arising from neocortex cross the midline in teh posterior two‐thirds of the anterior commissure before terminating in contralateral neocortcial areas. The vast majority of fibers terminated in the deep cortical layers IV, V, VI. There was degeneration in layer III and occasionally in layer II, but essentially never in layer, I. A small central portion of striate cortex receives very few commissural fibers.Following thalamectomy, degenerating fibers could be traced to all areas of neocortex. One system of thalamocortical fibers terminates coextensively with commissural fibers in the deep layers IV, V, VI. A second system of thalamic projection arises from thalamic cells, traverses the cortical layers in parallel fascicles at 900 to the pial surface, bifurcates and ends in the thick outer plexiform lamina (layer I) of neocortex. These fibers run for some distance parallel to the pial surface before terminating among apial dendrites of neurons from all cell layers. This system of layr I thalamocortical connectiions appears in all neocortical areas, even in primary receptive cortex in teh opossum. There is little evidence of the highly specialized axonal arborizatiions that characterize layer IV thalamic terminations in the primary receptive cortex of eutherian mammals.
An anatomical and electrophysiological study of the retina of the owl monkey, Aotes trivirgatus
Authors: Hamasaki D. I. 
Published: January 2005

AbstractHistological study of the retina of the owl monkey demonstrated two types of photoreceptors. The rods predominated and had characteristics of rods of other primates. The second type of receptor has been identified as a cone because (1) its inner segment was short and pyramidally shaped, (2) its outer segment was tapered and shorter than the rods, (3) it changed shape and size throughout the retina, and (4) it had different staining properties from the rods.Using the ERG as an index of retinal activity, the dark‐adaptation and flicker fusion frequency curves were shown to be made up of a photopic and scotopic segment. The photopic and scotopic b‐waves could be demonstrated during dark‐adaptation.
Projection of optic fibers to visual centers in α turtle (Emys orbicularis)
Authors: Kosareva A. A. 
Published: January 2005

AbstractStudies of retinal projections to the thalamus and midbrain of the turtle were based on a personal modification of the Nauta‐Laidlaw technique (modified Nauta method) after unilateral enucleation. Decussation of optic fibers in the chiasma is incomplete. In the thalamus, optic fibers are found to terminate in three nuclei – with greater density in the corpus geniculatum laterale (lateral geniculate body) (LGB) and more sparsely in the nucleus suprapeduncular and nucleus ovalis. Retinal projections to the LGB assume a focal pattern, being somewhat more compact in the lateral neuropil region. Optic fibers are also shown to end in a group of pretectal nuclei: n. pretectalis dorsalis, n. lentiformis mesencephalis, n. comissurae posterior. In addition, terminations of optic fibers have been revealed in the three upper layers of the tectum. Peculiarities of preterminal and terminal degeneration of retinal fibers have been distinguished in the different tectal layers. In the second stratum, terminations of large fibers are mostly seen with a characteristic appearance of lumpy pericellular (preterminal) degeneration. In the third stratum, both large and finer fibers degenerate, showing fine debris of preterminal degeneration. Different patterns of terminal degeneration have been revealed in tectum and thalamus. The maximal size of optic fibers in the tectum proves to be larger than in thalamus. Available evidence is discussed with particular reference to comparison of the phylogenetically more recent retinothalamic system and more ancient retinotectal system.
Extensive cortical depth measurements and neuron size increases in the cortex of environmentally enriched rats
Authors: Diamond Marian C. , Lindner Bernice , Raymond Alma 
Published: January 2005

AbstractThis study is another in a series of investigations attempting to define the changes in the brain as a consequence of environmental manipulation. Cortical depth and neuron size measurements were taken on brains of rats from enriched (ECT) and impoverished (IC) environments.Celloidin embedded, 10 μ, transverse sections of formalin fixed rat brains were stained wiith thionin. Ten representative sections from each brain were taken, utilizing subcortical landmarks to insure uniform sampling. Cortical depths were measured on microslide projected drawings beginning at the midline and proceeding laterally. The number of readings per hemisphere ranged from 41 to 46. The greatest increases in depth were found in the sections from the posterior commissure landmark. At this position the increases in four regions, proceeding medially to laterally, were as follows: A, 5.2% (p < 0.001); B, 6.3% (p < 0.001); C, 3.2% (p < 0.01); D, 1.6% (NS).Perikarya and nuclear size measurements were taken with a planimeter on microfilm projected outlines. The cortex was divided into upper, middle and lower levels, and within each third, cell size increases were noted, with the outer third showing the greatest increases. The ECT perikarya were greater than the IC by 17.7% (p < 0.001) in the upper level, by 7.2% (p < 0.05) in the middle level, and by 11.6% (p < 0.01) in the lower level.