bluuebunny/crossref_metadata_2025_split huggingface dataset:
A golgi study on the subthalamic nucleus of the cat
Authors: Iwahori Nobuharu 
Published: January 2005

AbstractThe subthalamic nucleus (ST) of kittens was studied by means of the rapid Golgi silver impregnation method.The neurons of the ST were classified into three types. Type I neurons, the main constituents of the ST, had oval or polygonal cell bodies with a mean diameter of 26 μm by 36 μm and four to six primary dendrites. Type II neurons had multipolar or polygonal cell bodies, which measured an average 31 μm by 43 μm and emitted four to seven primary dendrites. The cell bodies of the type III neurons were polygonal in shape, measured 23 μm by 26 μm in average and emitted four to six primary dendrites. The dendrite bundle and the dendrite pallisade were observed. Frequently dendrites of the ST extended into the cerebral peduncle (CP), and even cell bodies of some ST neurons were located within the CP. All of the parent axons of the ST neurons coursed rostrally, although intra‐ and extra‐nuclear axon‐collaterals arising from the ST neurons travelled rostrally, caudally or caudomedially.The afferent fibers to the ST were divided into three groups; afferents via the Meynert's commissure (MC), descending and ascending afferents. The MC fibers, which ran across the CP, gave terminals to the ST. The descending afferents were axon‐collaterals of fibers descending in the CP and those of fibers running through the ST. The ascending afferents were also axon‐collaterals arising from ascending fibers in the CP. In addition to these afferents, many descending and ascending fibers of passage ran through the ST without emitting axon‐collaterals.
Patterns of retinal terminations and laminar organization of the lateral geniculate nucleus of primates
Authors: Kaas J. H. , Huerta M. F. , Weber J. T. , Harting J. K. 
Published: January 2005

AbstractAutoradiographic tracing procedures have been used to study the organization of retinogeniculate axons in seven primates, i.e., four species of New World monkeys, one species of Old World monkeys and two species of prosimians. These data suggest that the basic primated pattern of geniculate lamination consists of two parvocellular layers, two magnocellular layers, and two poorly developed and highly variable superficial (S) layers which are ventrally lacoted. Ocular input to each member of each of the three pairs differs. In the macaque, the squirrel, and the saki monkey, the parvocellular layers subdivide and interdigitate into four leaflets so as to give the appearance of four parvocellular “layers”. These leaflets are much less extensive in the owl and marmoset monkeys. In some individual macaque monkeys, there is further splitting of the parvocellular leaflets into subleaflets, giving the appearance of six parvocellular “layers”. The prosimians (galago and slow loris) have two additional layers that are not found in pithecoid primates, and only one superficial layer is apparent. The two additional layers are termed “koniocellular” since they consist of very small cells. Finally, New and Old World monkeys have both ipsilateral and contralateral retinal input to the interlaminar zones.We conclude that the basic pattern of lateral geniculate organization is six layers, but not the traditional six. Prosimians have evolved two additional layers, the koniocellular layers, and have possibly lost one superficial layer. Both New World and Old World monkeys have elaborated the parvocellular layers by forming leaflets to varying extents. With the possible exception of the single S layer in prosimians, layers form pairs that are similar in cell types, but different in ocular input.
The efferent connections of the anterior hypothalamic area of the rat, cat and monkey
Authors: Saper C. B. , Swanson L. W. , Cowan W. M. 
Published: January 2005

AbstractThe general morphology and topographic relations of the anterior hypothalamic area (AHA) in the rat, cat and squirrel monkey have been described, and its efferent connections analyzed autoradiograpically, after small injections of 3H‐labeled amino acids into, or around, the area. In all three species the AHA is rather poorly separated from the surrounding preoptic and hypothalamic areas and nuclei but shows three distinct cellularcondensations, lacated rostrally, and posterodorsally. Closely associated with the AHA are the retrochiasmatic area, the anterior periventricular nucleus and the scattered neurons usually referred to as the accessory supraoptic nucleus.The AHA has primarily short connections to the adjoining medial preoptic area, the lateral hypothalamic area, the periventricular nucleus, the dorsomedial nucleus, and to the “capsule” of the vertromedial nucleus. However, it also has certain mor4 distantprojections, rostrally to a narrow zone centered in the ventral part of the lateral septal nucleus, and caudally to the dorsal premammillary nuclei, the posterior hypothalamic area and the central gray. There is some evidence to suggest that the various subdivisions of the AHA have different afferent connections. Thus the posterodorsal cell condensation appears to give rise to the bilateral projection to the dorsal premammillary nuclei, while the projections to the septum, the posterior hypothalamic area and the central gray seem to have their origin in the central condensation. Similarly, the retrochiasmatic area sends its efferents through the ventral supraoptic commissure to the amygdala, the anterior periventricular nucleus contributes to the periventricular fiber system and to the external lamina of the median eminence, and the accessory supraoptic neurons project to the internal lamina of the median eminence.
Some features of the spatial organization of the central nucleus of the inferior colliculus of the cat
Authors: Roth G. L. , Aitkin L. M. , Andersen R. A. , Merzenich M. M. 
Published: January 2005

AbstractA series of neuroanatomical and neurophysiological experiments have been conducted within the central nucleus of the inferior colliculus (ICC) of the cat in order to determine some features of the spatial organization of the nucleus. Results from these experiments have demonstrated: (1) the origins of the auditory brain stem afferents to ICC and the topography of those projections in relation to the cochleotopic organization of ICC; (2) the segregation of at least some of those brain stem projections within ICC; and (3) ICC neurons with similar response properties (response properties which are often similar or identical to those of neurons in brain stem auditory nuclei) are often clustered within the nucleus. These results provide evidence that the laminated division of the ICC probably consists of anatomically, physiologically, and functionally distinct subdivision and that some aspects of auditory sensation may be encoded or represented separately (i.e., in spatially distinct “regions”) within the nucleus.
Properties of neurons in cat's dorsal lateral geniculate nucleus: A comparison between medial interlaminar and laminated parts of the nucleus
Authors: Dreher Bogdan , Sefton Ann Jervie 
Published: January 2005

AbstractWe studied the receptive field properties of 460 cells in the cat's dorsal lateral geniculate nucleus (LGNd), 108 cells were located in the medial interlaminar nucleus (MIN) and 352 in the laminated part of the LGNd.In both the MIN and laminated parts of the LGNd, relay cells belonging to all three functional classes (W, X and Y) have been identified. Of cells in the laminated LGNd, about 32.5% were Y cells, about 54.5% were X cells and about 8.5% were W cells. By contrast, in the MIN, about 84% were Y cells, only about 4.5% being X cells and about 7.5%, W cells. In the laminated LGNd, Y cells represented 25% of cells with receptive fields near the area centralis (0–3° eccentricity group) and about 42% in the group of cells with the most peripherally located receptive fields (20–40° eccentricity group). A similar but much weaker trend was observed in the MIN. In the laminated LGNd but not in the MIN the receptive field center sizes increased with increasing eccentricity of receptive field position. At any eccentricity, receptive field centers of MIN Y cells tended to be larger than those of Y cells in the laminated LGNd.Response latency ranges to orthodromic and antidromic stimulation were the same for cells located in the laminated LGNd and those in the MIN. However, the mean response latency to stimulation of the optic chiasm was significantly shorter for Y cells in MIN than for Y cells in the laminated LGNd.Our results suggest that the most numerous cells observed histologically in the MIN, class 1 cells of Guillery ('66) are morphological equivalents of Y cells.
Properties of superior colliculus neurons in the golden hamster
Authors: Stein Barry E. , Dixon James P. 
Published: January 2005

AbstractA laminar representation of sensory modalities was present in the hamster superior colliculus (SC) with upper laminar cells being exclusively visual, while intermediate and deeper layer cells were visual, somatic acoustic or multimodal.Receptive field (RF) properties of visual SC cells were studied quantitatively with stationary spots and moving bars of light of various sizes, velocities and directions of movement. The most effective stimuli were usually less than half of the diameter of the RF. Increasing stimulus size beyond a critical range produced progressively lower discharge rates even though the stimulus was confined within the borders of the RF. Low velocities (10–50°/sec) were most frequently optimal for both upper and lower laminar cells and the majority of cells were directionally selective. Movements in the upper nasal direction usually elicited the highest discharge rates and were thus preferred most frequently. However, directional preferences often could be minimized, or obliterated, by employing nonoptimal stimulus sizes and/or velocities.Most intermediate and deeper laminar somatic cells could be activated by gentle cutaneous stimuli and a general somatotopic plan, which was in register with the overlying visuotopy, was noted. Cells optimally, or solely, activated by noxious stimuli were also located, but RFs of such cells were extensive and a somatotopic plan was not apparent.Although species differences are apparent, the similarities between the organization and the RF properties of SC cells of the hamster and distantly related species are striking. Apparently the same SC system is adaptive in diverse species despite the very different behavioral repertories of these animals and their different ecological niches.
The formation of afferent patterns in the somatosensory cortex of the neonatal rat
Authors: Killackey Herbert P. , Belford Gary R. 
Published: January 2005

AbstractIn the rat, the clustered pattern of thalamocortical afferent terminals to the “barrel field” portion of primary somatosensory cortex replicates the arrangement of vibrissae on the face, and the pattern of the terminals can be altered by the removal of vibrissae at birth (Killackey et al., 1976). These patterns of terminals were studied using the enzyme succinic dehydrogenase (SDH) because in somatosensory cortex the activity levels of SDH closely correspond to the patterns of thalamocortical afferent terminals.The present experiments show that the pattern of high SDH segmentation in the portion of layer IV of somatosensory cortex that is related to the vibrissae develops during postnatal Days 3 through 6. Activity related to the centers of individual clusters is first visible, with indistinct boundaries. At later times the edges of individual clusters become apparent. Further, in animals with Row C of vibrissae removed at birth, the abnormal SDH segmentation in somatosensory cortex develops with a time course similar to that of normal animals. At ages when edge boundaries are first distinct, a fused band corresponding to the removed row of vibrissae is present. Thus the aberrant organization seen in the adult cortex is the result of an abnormal initial development, not a later reorganization from a normal pattern. And indeed, vibrissae removal at Day 5 or 6 does not result in an aberrant cortical SDH pattern. Finally, after removal of all five rows of mystacial vibrissae at birth, the cortical SDH pattern seen at postnatal Days 6 and 7 consists of five bands in place of the normally present five rows of clusters. This may indicate that closer relationships exist between vibrissae within one row than vibrissae in adjacent rows.
An ultrastructural study of schwann cell response to axonal degeneration
Authors: Payer Andrew F. 
Published: January 2005

AbstractAdult Sprague‐Dawley rats were used to prepare isolated and distal segments of ovarian, vagus and saphenous nerves. Isolated segments were prepared by cutting between double ligatures followed by retracting and anchoring the proximal and distal segments 0.5 cm or more away from the isolated piece. After various intervals between 3 and 123 days the rats were perfused with buffered glutaraldehyde and nerves were processed for electron microscopic examination. Cross sections of isolated and distal segments of all nerves displayed an abundance of mostly circular profiles containing microtubules and filaments that were indistinguishable from those in unmyelinated nerve fibers. Many such profiles were nested against perinuclear Schwann cell cytoplasm, others were present in isolated clusters enclosed only by basement membrane. Examples of continuity between the nerve‐like profiles and perinuclear cytoplasm of Schwann cells were found in longitudinal sections. In time, the number of such processes gradually diminished, but 123 days after transection they still could be found. It was concluded that Schwann cells in isolated and distal segments of transected nerves develop great numbers of small cylindrical processes that are arranged in bundles parallel to the long axis of the degenerated nerve. These processes had an arrangement of cytoplasmic organelles similar to axons of the proximal segment and the contralateral nerve. However the processes differed from most mature axons in that they were not ensheathed by Schwann cell cytoplasm with a mesaxon.
The afferent and efferent connections of the ventromedial thalamic nucleus in the rat
Authors: Herkenham Miles 
Published: January 2005

AbstractThe afferent and efferent connections of the ventromedial (VM) nucleus of the thalamus in the rat were studied by experiments using the methods of retrograde cell marking by horseradish peroxidase (HRP) and anterograde fiber tracing by autoradiography. Tritiated amino acids deposited microelectrophoretically into VM label a cortical projection that is distributed to a sharply defined superficial portion of layer I of almost the entire extent of the ipsilateral neocortex. The labeling is most dense at frontal cortical levels, where fibers radiate through the deeper layers to terminate in the outer one‐quarter of layer I throughout all neocortex rostral to the genu of the corpus callosum. A lesser number of labeled fibers extends caudally in a supracallosal location to innervate parieto‐occipital cortical areas. Labeled collaterals ascend through the cortical layers to reach layer I, where grains in the superficial portion are found in a gradually decreasing rostrocaudal gradient of density that reaches the caudal pole of the hemisphere. Coronal sections at most levels contain a band of labeling in layer I that extends uninterrupted from the callosal sulcus at the midline to the banks of the rhinal sulcus laterally. Caudal retrosplenial and ventral temporal areas appear to be the only sectors of neocortex spared by the ubiquitous projection. Evidence for additional terminal distribution in deeper layers is found only in the dorsal and lateral sectors of the cortex rostral to the genu where sparsely labeled bands appear in layers III and V. The nearly exclusive distribution of VM's cortical afferents to layer I is compared and contrasted with multilaminar distributions of other “unspecific” cortical afferent fibers.HRP injected into VM labels neurons in a variety of structures at levels ranging from the frontal cortex to caudal medulla. Cell labelling in the globus pallidus, deep layers of the superior colliculus, cerebellar nuclei and the substantia nigra, pars reticulata suggest that VM is a point of convergence for several components of the extrapyramidal motor system. The nigrothalamic projection is topographic: medial and lateral districts of the pars reticulata are connected to medial and lateral districts of VM, respectively. A dorsal‐ventral association may also obtain. Cell labeling in the prefrontal cortex, the cortex along the rhinal sulcus, the lateral habenular nucleus, tegmental and medullary reticular formations, and parabrachial nuclei indicates that VM also receives projections from more heterogeneous sources.
Electron microscopic evidence of a ventronasal to dorsotemporal variation in fiber size in pigeon optic nerve
Authors: Duff Thomas A. , Scott Grayson 
Published: January 2005

AbstractUsing a uniform sampling method, electron‐microscopic examination of pigeon optic nerve revealed a dorsotemporal to ventronasal gradient in mean fiber size. In the dorsotemporal region small, myelinated axons (mean diameter = 0.87 μm, S.D. = 0.27) were predominant. Also unique to this region were scattered clusters of fine, unmyelinated fibers. A wider, bimodal spectrum in fiber size (mean diameter = 1.50 μm, S.D. = 0.66) was found in the ventronasal region of the nerve. Axons located in the area between these regions possessed a (mean diameter of 1.15 μm, S.D. = 0.43) This gradient, constant throughout the length of the nerve, resulted from a nasal‐to‐temporal diminution in size and frequency of large fibers superimposed upon a relatively uni form small fiber base. The total number of fibers within the nerve, excluding those comprising the unmyelinated clusters, was calculated to be approximately 2.3 × 106. The overall distribution in fiber size appeared to be unimodal with the peak at 0.75 μm and mean diameter = 1.04 μm, S.D. = 0.44. Although previous invertigators have reported that cross‐sectional analysis of pigeon optic nerve revealed a homogeneous distribution in fiber size, the findings of the present study may be more compatable with anatomical and physiological features of pigeon retinotectal organization. These features include visual field acuity gradients, ganglion cell population pattern, and dendity fields of tectal afferent terminations.
A neurophysiological determination of the vertical horopter in the cat and owl
Authors: Cooper Michael Lee , Pettigrew John D. 
Published: January 2005

AbstractWe have undertaken a determination of the vertical horopter in two species by simultaneously mapping the receptive field positions of binocular cortical neurons at various elevations along the zero azimuthal meridians.In the paralyzed cat our recordings show that the zero meridians of the two eyes are parallel and vertical under paralysis. Slit‐pupil photographs demonstrate that paralysis induces an average net intorsion of 9° between the two eyes. Correction back to the unparalyzed state results in the zero meridians themselves being out‐torted with respect to each other. Since the two eyes' zero meridians define physiologically the positions of corresponding retinal points, this out‐torsion results in a vertical horopter in the mid‐sagittal plane which is tilted away from the alert, unparalyzed cat.The limited eye movements of the owl permit the use of an unparalyzed preparation; it is therefore possible to avoid the problem of the cyclotorsion under paralysis which occurs in the cat. The results of our physiological analysis in the burrowing owl (Speotyto cunicularia) also reveal a tilted horopter in this terrestrial avian species.
The location of spinal neurons with long descending axons (long descending propriospinal tract neurons) in the cat: A study with the horseradish peroxidase technique
Authors: Matsushita Matsuo , Ikeda Michiko , Hosoya Yasuhiko 
Published: January 2005

AbstractThe distribution of spinal neurons with long descending axons was studied in the cat by means of retrograde transport of horseradish peroxidase. Labeled neurons appeared bilaterally in the cervical and the thoracic cord following injections in the lumbosacral cord. In some cases hemisections were made rostrally and contralaterally to the injections in an attempt to determine whether or not the axons crossed.Neurons with uncorssed descending axons were located in laminae I, V, VII and VIII. Lamina I neurons were present in all the spinal segments. In lamina V labeled neurons were distributed mainly laterally in the cervical cord but medially and laterally in the thoracic cord. In the upper cervical and the thoracic cord laminae VII and VIII neurons were distributed very densely along the lateral cord, accounting for 30% and 40% of the total labeled neurons, respectively. In the cervical enlargement they were located in the middle part of lamina VII and in lamina VIII, accounting for about 25% of the total labeled neurons. Neurons with crossed descending axons were found in laminae VI, VII and VIII, in the medial part of lamina VII including the intermediomedial nucleus of the thoracic levels and close to the central canal. Lamina V neurons were very small in number. The largest collections of labeled neurons were present in the medial part of laminae VII and VIII. They accounted for about 45% to 55% and 37percnt; of the total in the cervical and the thoracic cord.These neurons may function as the long spinal reflex paths for forelimb‐hindlimb synergies and the intercalated paths between the supraspinal descending tracts and the spinal motor centers.
Anatomical organization of the spinocerebellar system in the cat, as studied by retrograde transport of horseradish peroxidase
Authors: Matsushita Matsuo , Hosoya Yasuhiko , Ikeda Michiko 
Published: January 2005

AbstractThe distribution of spinocerebellar tract (SCT) neurons has been studied in the entire length of the spinal cord of the cat following injections of horseradish peroxidase into the cerebellum, and whether or not the axons of the labeled neurons crossed within the spinal cord was determined in cases with injections preceded by hemisections at the cervical levels.The SCTs were classified into the following corssed and uncrossed tracts according to the cell origin and the fiber course; The crossed SCTs originate from (1) the central cervical nucleus (the CCN‐SCT), (2) lamina VIII neurons of the cervical to the lumbar cord (the lamina VIII‐SCT), (3) spinal border cells (the border cell‐SCT), (4) neurons in the medial lamina VII of the lumbar to the caudal spinal segments (the medial lamina VII‐SCT), (5) ventral horn neurons (laminae VII and VIII) of the sacral and caudal segments (the ventral horn‐SCT) and (6) dorsal horn neurons (lamina V) of the sacral and the caudal segments (the dorsal horn‐SCT). The uncorssed tracts originate from (1) neurons of the medial lamina VI of C2 to T1 (the medial lamina VI‐SCT of the cervical cord), (2) neurons in the central part of lamina VII of C6 to T1 (the central lamina VII‐SCT of the cervical enlargement), (3) lamina V neurons of the lower cervical to the lumbar cord (the lamina V‐SCT), (4) Clarke's column (the Clarke's column‐SCT) and (5) neurons in the medial lamina VI of L5 and L6 (the medial lamina VI‐SCT of the lumbar cord).The present study suggests that the spinocerebellar system originates from more diverse laminae than has previously been known, and further refined studies on the topographic projections of each tract will yield more important and valuable information in this field.