bluuebunny/crossref_metadata_2025_split huggingface dataset:
Quantitative studies of cell size in the cat's dorsal lateral geniculate nucleus following visual deprivation
Authors: Hickey T. L. , Spear Peter D. , Kratz Kenneth E. 
Published: December 2004

AbstractThe effects of visual deprivation upon dorsal lateral geniculate (DLG) cell size were compared for seven kittens reared with monocular lid‐suture (MD), seven with binocular lid‐suture (BD), and six with one eye lid‐sutured and the other eye enucleated soon after birth (MD‐E). Six additional kittens were reared normally for comparison. For each kitten the cross‐sectional areas of 300 cells were measured in one or both nuclei. Measurements were taken from the binocular segment of laminae A and A1 and th monocular segment of lamina A.In agreement with previous studies, cells in th binocular segment of the deprived laminae of MD cats were smaller (33‐34%) than those in the non‐deprived laminae. Comparisons with normal animals indicated that this difference was due to an increase (10‐15%) in size of cells in the non‐deprived laminae as well as a decrease (23‐25%) in size of cells in the deprived laminae. Cells in the monocular segment also were affected by deprivation in MD cats, and this effect increased with the age (and duration of the deprivation) of the animal. However, it was always smaller than the decrease in sell size in the binocular portion of the DLG.In BD kittns, DLG cells were smaller (7‐12%) than normal in all portions of the nucleus, including both the binocular and monocular segments. Direct comparisons between the deprived laminae of MD and BD kittens indicated that the decrease in cell size was greater for MD kittens in the binocular segment, but tended to be greater for BD kittens in the monocular segment. IN MD‐E kittens, DLG cells in the deprived laminae were smaller (11‐17%) than normal in all portions of the nucleus, including both the binocular and monocular segments. Thus, the effects of deprivation were similar to those in BD kittens, even though inputs from the deprived eye had been placed a competitive advantage in MD‐E kittens. These results indicate that two factors may affect cell size in the DLG of visually deprived cats: deprivation per se and abnormal binocular competition.Finally, separate analyses for the ten largest and the ten smallest cells in each lamina of each cat were carried out in an attempt to determine if the changes in cell size were limited to the largest cells. In every case, differences observed for the total sample of cells were paralleled by differences from normal of both the largest cells present and the smallest cells present in the deprived laminae. Since at least two alternative interpretations can account for this finding, the question of whether the large cells are selectively affected by visual deprivation remains unanswered in the cat.
Regeneration of fungiform taste buds: Temporal and spatial characteristics
Authors: Cheal Marylou , Oakley Bruce 
Published: December 2004

AbstractThe gross morphology of the tongue of the Mongolian gerbil (Meriones unguicultatus), the location of papillae and taste buds, and the normal innervation pattern of the tongue asnd taste buds were determined. The chorda tympani nerve was interrupted to produce degeneration of fungiform taste buds. Regenerating chorda tympani axons followed the original nerve pathways in the tongue en route to the furniform papillae in the epithelium where they initiated the regeneration of taste buds. The spastial distribution of reinnervated fungiform papillae and reformed taste buds was examined 7 to 19 days following surgery. Beginning at eight days following chorda tympani interruption there was a progressive increase, first, in the proportion of fungiform papillae that were reinnervated, and later in the number of reformed taste buds. On the basis of these measures it was concluded that a taste bud is reformed one to two days after reinnervation of its papilla. From the time course of reinnervation of the fungiform papillae it was calculated thast some fibers regenerated at rates in excess of 2mm/day. Regeneration was precise and systematic. The regenerating chorda tympani fibers accurately returned to the fungiform papillae; they did not follow the pasthways of lingual nerve axons. In the initial stages of recovery both reinnervated papillae and reformed taste buds weere preferentially located toward the front of the tongue; the reinnervation of posterior fungiform papillae was delayed.
Taste fiber responses during reinnervation of fungiform papillae
Authors: Cheal Marylou , Dickey William P. , Jones Lef B. , Oakley Bruce 
Published: December 2004

AbstractCrushing or transecting the chorda tympani nerve of the gerbil (Meriones unguiculatus) caused ipsilateral degeneration of taste buds in the fungiform papillae. In less than two weeks some taste fibers regenerated into the tongue and formed new taste buds and receptor cells. The recovery process was evaluated electrophysiologically in 53 gerbils by acute recording proximal to the nerve injury site. Initially the chorda tympani was electrically silent. In gerbils tested at later times spontaneous activity appeared. This was followed by responses to pressure on the tongue. Taste responses returned as early as dasy 11. The receptive field of regenerated taste fibers was limited to a small number of fungiform papillae. Taste responses were always associasted with the presence of one or more taste buds in the receptive field. Taste buds identified as responsive to chemicals contained some fusiform cells.We found thast the taste responses of single fiber, few‐fiber and multi‐unit preparations reflected the diversity of responses found in normal taste axons as determined by recording from 26 normal single fibers and 27 normal whole nerves. The early emergence of a variety of fiber types and responses to many chemicals in regeneration is inconsistent with the proposition that the relative chemical responsiveness of a receptor cell is strictly a function of its age; the response of a given young taste receptor is not necessarily limited to a few of the standard taste stimulants.
Topographic organization of the projections from cortical areas 17, 18, and 19 onto the thalamus, pretectum and superior colliculus in the cat
Authors: Updyke B. V. 
Published: December 2004

AbstractThe distribution of cortical projections from areas 17, 18, and 19 to the lateral thalamus, pretectum, and superior colliculus was investigated with the autoradiographic tracing method. Cortical areas 17, 18 and 19 were demonstrated to project retinotopically and in register upon the dorsal lateral geniculate nucleus, medial interlaminar nucleus, lateral zone of the lateral posterior complex, nucleus of the optic tract and superior colliculus. Area 19 was shown to project retinotopically upon the pulvinar nucleus. Clear retinotopic organization was not demonstrable in the projections of areas 17, 18 and 19 to the reticular complex of the thalamus and ventral lateral geniculate nucleus, or in the projection of area 19 to the anterior pretectal nucleus.The cortical projections were employed to define the retinotopic organization of the nucleus of the optic tract, pulvinar nucleus, and lateral zone of the lateral posterior complex. The cortical projections show the vertical meridian to be represented caudally, with the lower visual field represented laterally, and the upper visual field medially, within the nucleus of the optic tract. The projections of area 19 to the pulvinar nucleus demonstrate the lower visual field to be represented rostrally and the upper visual field caudally in this nucleus; the vertical meridian to be represented at the lateral border and the visual field periphery to be represented at the medial border of the pulvinar nucleus. Cortical projections to the lateral zone of the lateral posterior complex demonstrate the lower visual field to be represented rostrally and the upper visual field caudally; the vertical meridian to be represented at the medial limit and the visual field periphery at the lateral border of the termination zones.On the basis of the experimental findings, a new terminology is introduced for the feline lateral posterior complex. Divisions are proposed which correspond to zones with demonstrably distinct afferent input. The pulvinar nucleus is defined by the distribution of projections from area 19. Three flanking divisions are defined within the lateral posterior complex; a lateral division recipient of projections from area 17, 18 and 19, an interjacent division recipient of projections of the superficial layers of the superior colliculus, and a medial division flanking the tectorecipient zone medially.
Tectal efferents in the banded water snake, Natrix sipedon
Authors: Ulinski Philip S. 
Published: December 2004

AbstractVisual information reaches the dorsal thalamus by two distinct routes in most reptiles. Retinal efferents terminate directly in the dorsal lateral geniculate nucleus (DLGN). Retinal information is also channeled indirectly through the tectum to nucleus rotundus. Retinal projections to DLGN and tectum are also well esablished in snakes, but the status of the tecto‐rotundal link of the indirect visual pathway is uncertain.Thus, tectal efferents were studied with Fink‐Heimer methods in banded water snakes (Natrix sipedon). The tectum gives rise to crossed and uncrossed projections to the brainstem reticular formation. Commissural connections are effected with the contralateral tectum via the tectal and osterior commissures. tectum projects densely to the ipsilateral basal optic nucleus. Bilateral ascending projections reach the pretectal area, nucleus lentiformis mesencephali, lateral habenular nuclei, and posterodorsal nuclei. Ascending projections reach the ventral lateral geniculate and suprapeduncular nuclei. there is a diffuse projection to the central part of the caudal thalamus and a dense, bilaternal projection to the DLGN.These results indicate that the relation of the tectum to the dorsal thalamus is different in snakes than in other reptiles. Nucleus rotundus is either absent or poorly differentiated and there is a strong convergence of the direct and indirect visual pathways at DLGN.
Development of the geniculocortical pathway in rat
Authors: Lund R. D. , Mustari M. J. 
Published: December 2004

AbstractMost cells of the dorsal lateral geniculate nucleus of rats are generated of fetal days 12 to 14. Their axons invade the telencephalon on fetal day 16 and run in the intermediate zone just below the cortical plate, reaching the visual area on fetal day 18. The axons do not invade the cortical plate significantly until close to birth (day 22 of gestation) and reach their zone of terminal distribution between postnatal days 1 and 4. In subsequent days the projection becomes progressively more heavily distributed in layers IV and I, and synapses of thalamic origin can be identified in these layers. While cells destined for layers IV cross the intermediaste zone at the time that thalamic axons first arrive, this coincidence of growth does not seem to be a factor which determines the specificity of patterns of thalamocortical connections since the cells reach layer IV several days before the axons. It is unclear why the axons should wait several days in the region immediately below the cortical plate before invading, although there is a parallel in previous studies on the development of the chick retinotectal pathway (Crossland et al., '75).
Telencephalic efferents of the tiger salamander Ambystoma tigrinurn tigrinum (Green)
Authors: Kokoros James J. , Northcutt R. Glenn 
Published: December 2004

AbstractThe efferent projections of the telencephalon in the tiger salamander were examined by the Nauta and Fink‐Heimer methods following unilateral hemispherectomies, rostral hemispheric ablations and pallial lesions. The cerebral hemisphere connects with most areas of the contralateral hemisphere via the pallial, anterior and habenular commissures. The descending fibers travel in the medial and lateral forebrain bundles and in the tracts comprising the stria medullaris. Degenerating fibers and terminals were present throughout the diencephalon but were more abundant ipsilaterally. Fibers reach the pretectum and optic tectum via dorsal and ventral pathways. There is a heavy projection to the midbrain tegmentum and a sparse projection to the tectum via the ipsilateral lateral forebrain bundle. This tract continues into the medulla oblongata and the cervical spinal cord. Rostral and dorsal hemispheric ablations revealed that the majority of fibers forming the olfacto‐peduncular tract originate in the ventral, rostral one‐third of the hemisphere. It was also determined that the majority of the descending efferent fibers located in the lateral forebrain bundle originate from the caudal lateral hemispheric wall, and that these fibers form connections characteristic of mammalian corticofugal and striatofugal systems. The cytoarchitecture and connections of the caudal lateral hemispheric wall suggest that it is homologous to parts of motor isocortex and amygdala of amniotes.
An autoradiographic study of the efferent connections of the superior colliculus in the cat
Authors: Graham Jean 
Published: December 2004

AbstractThe differential projections of the three main cellular strata of the superior colliculus have been examined in the cat by the autoradiographic method. The stratum griseum superficiale projects caudally to the parabigeminal nucleus and rostrally to several known visual centers: the nucleus of the optic tract and the olivary pretectal nucleus in the pretectum; the deepest C laminae of the dorsal lateral geniculate nucleus; the large‐celled part of the ventral lateral geniculate nucleus; the posteromedial, large‐celled part of the lateral posterior nucleus of the thalamus. Several of these projections are topographically organized.The stratum griseum profundum gives rise to most of the descending projections of the superior colliculus. Ipsilateral projections pass to both the dorsolateral and lateral divisions of the pontine nuclei, the cuneiform nucleus, and the raphe nuclei, and to extensive parts of the brainstem reticular formation: the tegmental reticular nucleus, and the paralemniscal, lateral, magnocellular, and gigantocellular tegmental fields. Contralateral projections descending in the predorsal bundle pass to the medial parts of the tegmental reticular nucleus and of some of the tegmental fields, the dorsal part of the medial accessory nucleus of the inferior olivary complex, and to the ventral horn of the cervical spinal cord. Ascending projections of the stratum griseum profundum terminate in several nuclei of the pretectum, the magnocellular nucleus of the medial geniculate complex and several intralaminar nuclei of the thalamus, and in the fields of Forel and zona incerta in the subthalamus.The strata grisea profundum and intermediale each have projections to homotopic areas of the contralateral superior colliculus, to the pretectum, and to the central lateral and suprageniculate nuclei of the thalamus. However, the stratum griseum intermediale has few or no descending projections.
The origin of spinocerebellar pathways. I. The nucleus cervicalis centralis of the cranial cervical spinal cord
Authors: Cummings J. F. , Petras J. M. 
Published: December 2004

AbstractThe origin of spinocerebellar projections from the cranial cervi cal spinal cord was studied in neonatal dogs following cerebellar ablations or the injection of horseradish peroxidase (HRP) into the cerebellum. Cerebellar ablations produced distinct retrograde changes of three types: type I response or cen tral chromatolysis; type II response or ghost cells; and type 111 response or neu ronal loss and gliosis. These ablation‐induced changes were evident in the cells of the nucleus cervicalis centralis. The results of hemicerebellectomy, unilateral cer ebellar pedunculotomy, and cordotomy established that the cells of this nucleus project contralaterally to the cerebellum. Cytoarchitectonic study revealed that this nucleus is composed of clustered medium‐sized, multipolar, chromatophilic neurons located in the zona intermedia of the C1‐C4 segments. The retrograde la beling of central cervical neurons following cerebellar injections of HRP con firmed the results obtained with the axonal reaction.Anterograde fiber degeneration was present in the central cervical nucleus following dorsal rhizotomy in the dog and cat. These experiments demonstrated dorsal root fibers among the somata of central cervical neurons rendered chromatolytic following cerebellectomy in the dog. Electron microscopic evidence is presented for the presence of degenerated dorsal root terminals upon the dendrites and somata of central cervical neurons.The nucleus cervicalis centralis forms a direct link between neck afferents and the cerebellum by way of a crossed cervicospinocerebellar pathway. Evidence could not be found for the presence of a spinocerebellar projection originating in the nucleus ceruicalis lateralis.
The distribution of acetylcholinesterase in the central nervous system of jumping spiders and wolf spiders (Arachnida, Araneida: Salticidae et Lycosidae)
Authors: Meyer Wilfried , Idel Karl 
Published: December 2004

AbstractThe distribution and activity pattern of acetylcholinesterase in the central nervous system of salticid and lycosid spiders has been studied. Enzyme activity was limited to the neuropile mass. The salticid and lycosid species investigated showed different intensities of enzyme reactions in the protocerebrum. The differences observed may be related to the some what contrasting habits of these spider families. Reactions were strong especially in the optic ganglia (lamina glomerularis, corpora pedunculata) and in the cerebral ganglion, while the central body showed only weak to moderate activity. In the cheliceral ganglia, as in the pedipalpal and the leg ganglia, including the fibre tracts of the ventral cord the demonstration of acetylcholinesterase was of moderate to strong intensity.
The effect of cortical lesions upon visual discriminations in binocularly deprived cats
Authors: Loop Michael S. , Sherman S. Murray 
Published: December 2004

AbstractFour cats were raised with binocular eyelid suture and, after their eyes were opened, were trained on a series of discrimination tasks. They performed at normal rates on the brightness task but indicated some difficulty with the pattern tasks. They then received large, bilateral occipito‐temporal cortex ablations. Postoperatively, this in no observable way affected their visually guided orienting behavior, but it did destroy their capacity to perform the preoperatively learned pattern tasks. Postoperative performance on the brightness task remained good. These data indicate that, in these deprived cats, there is little or no cortical development for visual orienting, but cortex is necessary for visual discrimination learning.
Presence of labeled monocytes, macrophages and microglia in a stab wound of the brain following an injection of bone marrow cells labeled with 3H‐uridine into rats
Authors: Imamoto K. , Leblond C. P. 
Published: December 2004

AbstractTo clarify the origin of the cells appearing in a stab wound of the parietal cortex, bone marrow cells from inbred Lewis rats were labeled in vitro with 3H‐uridine and injected intravenously into 36 rats of the same strain Just before or after the brain had been stabbed. The animals were sacrificed from 1 to 15 days after the injection of labeled cells. The cells in the wound were examined and the percentage of the various types recorded. Radioautographs were prepared of the wound and the surrounding neuropil, as well as of the corresponding region on the intact side; and they were searched for labeled cells.One day after the stabbing, the wound consisted of a central region containing fluid and red blood cells, and a marginal region of disorganized nervous tissue including granulocytes, monocytes and macrophages. Around the wound, the neuropil appeared normal, except for the perivascular areas appearing more cellular and distended than normally.During the next few days, the granulocytes and monocytes gradually disappeared from the wound. Meanwhile, the macrophages, which initially often showed monocytic features, became increasingly numerous. However, after the seventh day, the macrophages decreased in number, while many small cells appeared in the wound. These displayed a scanty basophilic cytoplasm rich in phagosomes and a nucleus with dense chromatin clumps similar to that seen in microgliaA search of the radioautographs revealed no labeled cell on the intact side, but 220 labeled cells on the injured side. Most of these cells were within the wound itself, and a few in the surrounding neuropil. Within the wound, labeled granulocytes and monocytes were common one day after injection, but disappeared after the first three days. Few labeled macrophages were observed at one day but many at three days; none were labeled after the seventh day, however, possibly due to turnover and loss of the 3H‐uridine labeled RNA.In the neuropil surrounding the wound, a few labeled cells identified as microglia were observed during the first three days after injection. They were located in perivascular areas, in satellite position to neurons and within the nearby subependymal layerIt is concluded that, under the influence of a stab wound, blood cells of bone marrow origin enter the wound and the surrounding neuropil. The presence of macrophages with monocytic features within the wound indicates that the monocytes transform into macrophages. The small cells displaying phagosomes and a microglia‐like nucleus, which become numerous after the seventh day, are tentatively interpreted as intermediates in the transformation of the monocytederived macrophages into microglia. Finally, the early labeled cells identified as microglia in the surrounding neuropil are interpreted as a direct transformation of monocytes into microglia.
The distribution of 3H‐Leucine labeled protein in the retinula cells of the crayfish retina
Authors: Hafner G. S. , Bok Dean 
Published: December 2004

AbstractThe synthesis and distribution of 3H‐leucine labeled protein was studied under conditions of diurnal lighting in the retinula cells of the crayfish retina with both light and electron microscopic autoradiography. Times ranging from two minutes to seven days after an intracardiac injection were analyzed. Quantification of the electron microscopic autoradiograms revealed that labeling of the cytoplasm was greater than the rhabdome at 2, 5, and 30 minutes and reached a peak at 12 hours. The rhabdome showed increasing activity after 5, 30, and 60 minutes, also reaching a peak at 12 hours. Radioactive label in cytoplasmic multivesicular bodies was higher than activity measured in either the total cytoplasm or rhabdome at all times except two minutes.Two temporally different microvillar labeling patterns were seen under diurnal lighting conditions. (1) Microvilli forming the slightly enlarged distal tip of the rhabdome retained their radioactivity at 1, 3, and 7 days, when labeling of the rest of the rhabdome microvilli was decreasing. (2) In the remainder of the microvilli, labeling at 1 and 12 hours appeared as a gradient which declined toward the proximal end of the rhabdome. This gradient subsequently reversed itself, showing heavier proximal labeling at three days.In a second experiment, labeling patterns in light and dark adapted rhabdomes were compared. In the dark, a distinct gradient of activity was observed with radioactivity concentrated distally and declining toward the proximal end of the rhabdome. A more even distribution of label was present in the light adapted eye, but a slight distal‐proximal gradient was still present. The dark adapted rhabdomes had more radioactivity per unit area than those exposed to light.