bluuebunny/crossref_metadata_2025_split huggingface dataset:
Reconstruction of axonal trajectory of individual neurons in the spinal cord using Golgi‐stained serial sections
Authors: Mannen Hajime 
Published: January 2005

AbstractA procedure bringing the axonal and dendritic cut ends found in the confronting planes of the serial sections face to face by means of serial photomicrographs provides a means for precisely reconstructing individual Golgiimpregnated neurons. Utilizing this method, it was possible to follow at the caudal level of a kitten's spinal cord the total course of the axons and dendrites of sixteen intramedullary neurons.The neurons located in the dorsal horn (lamine IV and V) send their long ascending axon into the lateral funiculus of the ipsi‐ or contralateral side, and, in one case, into the anterior funiculus of the ipsilateral side, giving off on the way several collateral to the dorsal half of lamina VII of the ipsi‐ or contralateral side. Some of the neurons found in the intermediate region and the ventral horn (laminae VII, VIII and X) distribute their axonal branches in the intermediate region or the ventral horn of the ipsi‐ or contralateral side or both sides, running throughout their course in the grey matter, while the others act in the same manner by way of the lateral or anterior funiculi. Axonal and collateral endings terminate with small terminal knobs. The total axonal length of the neurons observed, with the exception of some with a long ascending trajectory, varies from 1,680 μm to 6,480 μm.
Retrograde axonal transport of horseradish peroxidase in peripheral autonomic nerves
Authors: Ellison Jeffrey P. , Clark G. Michael 
Published: January 2005

AbstractAn exogeneous marker protein, horseradish peroxidase (HRP) was used to trace peripheral autonomic pathways in adult guinea pigs and cats. Small doses of HRP were injected into various organs and after a brief survival period, HRP activity appeared in the perikarya of autonomic neurons that supplied each injection site. After injection of HRP into the anterior chamber of the eye, reaction product was detected in the postganglionic sympathetic neurons of the superior cervical sympathetic ganglion. In another experiment, HRP reaction product was found in the cell bodies of the preganglionic sympathetic neurons that supply the adrenal medulla. These were located in the lateral gray column of the spinal cord at T6 and T7 segmental levels. Reaction product appeared in intramural postganglionic parasympathetic neurons close to an injection site in the wall of the urinary bladder and in a similar situation in Meissner's ganglia of the ileum. Following injection into the walls of the stomach and ileum, HRP labelled cells were detected in the nodose ganglion of the vagus and in preganglionic parasympathetic neurons in the dorsal motor nucleus of this nerve. After injection into the subepicardial tissue of the heart, reaction product appeared in the stellate ganglion and also in an upper thoracic dorsal root ganglion. These data suggest that HRP is taken up by peripheral autonomic nerves of all types, and then undergoes rapid retrograde axonal transport to the perikaryon. It appears, therefore, that HRP may be useful in tracing both motor and sensory peripheral autonomic pathways.
Late ultrastructural changes in neuronal mitochondria after lonizing radiation of the brain
Authors: Samorajski T. 
Published: January 2005

AbstractBrain tissue was examined for morphological changes at 12 and 16 months after focal irradiation of the brain in female mice. Irradiation was performed with deuteron beams derived from the 60‐inch Brookhaven cyclotron at a rate of 1925 rad second−1 through an anti‐Bragg device which produced uniform exposure. Experimental animals received a dose of 10,000 rad, covering a 9 × 5 mm area over the skull and extending into the brain for a depth of about 2 mm. An additional group of animals served as sham‐irradiated controls. Histological studies revealed extensive cell loss, vacuolation, and prominent vascular changes in irradiated regions of the brain at 16 months postirradiation. Ultrastructural examination of brain tissue at 12 and 16 months after irradiation revealed the presence of unusual elongated mitochondria with parallel arrays of cristae. Altered mitochondria were more prevalent at the longer post‐irradiation interval.
On the absence of a rubrothalamic projection in theb monkey with observations on some ascending mesencephalic projection
Authors: Hopkins David A. , Lawrence Donald G. 
Published: January 2005

AbstractIn order to determine whether there is a rubrothalamic projection in the rhesus monkey, the ascending degeneration resulting from electrolytic lesions made in the red nucleus and adjacent mesencephalon in animals surviving at least one year after bilateral interruption of the superior cerebellar peduncles (PCS) was studied by means of the Fink‐Heimer technique. In a necessary preliminary step it was shown that virtually all of the degeneration disappeared from the thalamus within twelve months after PCS interruption so that degeneration resulting from the subsequent electrolytic mesencephalic lesions could be attributed to interruption of non‐cerebellascending fibres.The results show that degeneration was present in the thalamus following the electrolytic mesencephalic‐diencephalic lesions but it could be accounted for on the basis of damage either to residual PCS fibres, to somatosensory pathways, to intrathalamic connections or to cell groups or projection fibres of the reticular formation, substantia nigra of globus pallidus. It is concluded that there is no direct rubrothalamic projection in the monkey and, in particular, no evidence of a projection from the red nucleus to the ventral lateral of ventral anterior thalamic nuclei.The results also indicate that the mesencephalic reticular formation is the main source of ascending afferents to the nucleus reticularis thalami. Some observations were made concerning nigrostriatal and nigrothalamic projections.Retrograde cell changes resulting from unilateral lesions made caudal to the red nucleus were studied in three animals. The observed cell changes are interpreted as being consistent with the conclusion that there is no rubrothalamic projection.
An estimate of the number of cells arising by division in mouse cerebral hemispheres from age one to 12 months: An autoradiographic study of DNA synthesis
Authors: Mareš Vladislav , Lodin ZdeněK , Jílek Miloš 
Published: January 2005

AbstractMale CBA strain mice aged 1, 2, 4, 6, 8 and 12 months were injected with 5 μCi of 6‐H3‐thymidine per gm body weight and killed two hours after the injection. Incorporation of the isotope, as a measure of DNA synthesis and cell division, was studied in the cerebral cortex and corpus callosum by light‐microscope autoradiography. DNA synthesis was found in a small number of nuclei of non‐neuronal cells, both of ecto‐ and mesodermal origin. The percentage of labeled cells (Labeling Index, or LI) decreased in both regions exponentially with age. On the base of measured LI values, the total number of cells arising from age one to 12 months was calculated. As the reference value the number of cells in one month‐old animals was taken. The calculated cell increment in the ectodermal population in the cortex amounted to 19.7–20.6% (average 20.2%) and to 196.0–425.0% (average 247.0%) in the corpus callosum (pairs of figures correspond to values calculated from LI values measured in sagittal and frontal sections). When all labeled cells (LC) were taken into consideration (of both ecto‐ and mesodermal origin) the corresponding cell increment ranged from 25.0–30.5% (average 26.8%) in the cortex and from 205.0–454.8% (average 263.0%) in the corpus callosum. The number of all newly arising cells in the whole hemisphere (including both cerebral cortex and corpus calosum) calculated from mean LI values of all LC in sagital and frontal sections amounted to 52.0%.It is suggested that the observed DNA synthesis and cell division, particularly in the corpus callosum and mesodermal cell groups of both regions studied, correspond mainly to renewal of cell populations. In the cerebral cortex accumulation of some newly arising cells in situ cannot be excluded.
Cerebellar cortical efferents of the posterior lobe vermis in a prosimian primate (Galago) and the tree shrew (Tupaia)
Authors: Haines Duane E. 
Published: January 2005

AbstractThe topographical organization of cerebellar cortical efferents of the posterior lobe vermis was studied in a prosimian primate (Galago senegalensis) and the tree shrew (Tupaia glis). Two patterns emerge; one which shows longitudinal zones of the entire vermis and a second which shows that individual lobules within the overall longitudinal pattern terminate in specific areas of the ipsilateral medial cerebellar nucleus (NM) and vestibular complex.The posterior lobe vermis consists of a narrow midline portion which projects bilaterally into the NM and a paramidline zone which projects only into the ipsilateral NM. These two zones are probably comparable to, and subdivisions of, Zone A of Voogd ('69). The lateral vermal zone projects primarily into the ipsilateral vestibular complex and/or interposed nuclei and appears to correspond to Zone B of Voogd ('69). Within this overall pattern individual lobules project into specific portions of the NM. From rostral to caudal (lobules VI to IX) terminal fields in the NM shift from dorsal and dorsomedial to ventral and ventrolateral. This is the inverse of the pattern of termination seen in the vestibular complex from lesions of the same lobules where from rostral to caudal (VI to IX) there are overlapping terminal fields from lateral to medial. With the exception of the narrow midline zone cerebellar corticonuclear projections of the posterior lobe vermis are ipsilateral. There is a more complex and more precise relationship between the posterior lobe vermis, NM and vestibular complex than previously suggested.
Different targets of different neurons in nucleus gracilis of the cat
Authors: Berkley K. J. 
Published: January 2005

AbstractEfferent projections of neurons in the cat nucleus gracilis to the ventrobasal complex (VB) of the thalamus and the dorsal accessory portion of the inferior olive (IOd) were studied using tracing techniques that exploit neuronal orthograde and retrograde intra‐axonal transport processes. These projections were studied in order to determine if the heterogeneity of the morphology, physiology and afferent input of the nucleus gracilis is paralleled by a similar heterogeneity in its efferent projections.In an orthograde study, 3H‐leucine and/or 3H‐proline were injected into the nucleus gracilis of different subjects in an attempt to label different proportions of large (>18 μ) and small cells. This procedure permitted study of the efferent targets of the two cell types. The amount of labeling in VB was a constant ratio of the number of large cells in the nucleus gracilis that had incorporated the isotope. This relationship was not observed for the small cells. The amount of labeling in IOd was dependent neither on the number of large nor the number of small cells that had incorporated the isotope.In a retrograde study following extensive injections of horseradish peroxidase (HRP) into the thalamus, only large cells (>18 μ) in the dorsal column nuclei were filled with HRP reaction product. These cells were located predominantly in clusters in the middle zone of the nucleus gracilis as well as rostrally. After injections including (but not confined to) the inferior olive, small cells located in the rostral and middle zones were filled with reaction product. A few large cells located ventrally in the middle zone of the nucleus gracilis and rostrally were also filled. Some of these ventrally located large cells may project in a collateral fashion both to the thalamus and to the inferior olive.The results of both the orthograde and retrograde studies are consistent with other evidence on the heterogeneity of the nucleus gracilis. These data strongly support the conclusion that the population of cells in the nucleus gracilis that projects to the thalamus overlaps with but is not identical to the population of cells that projects to the inferior olive.
Retinofugal pathways in the longnose gar Lepisosteus osseus (linnaeus)
Authors: Northcutt R. Glenn , Butler Ann B. 
Published: January 2005

AbstractRetinal projections were studied with autoradiographic and silver methods in the gar, Lepisosteus osseus, one of the two surviving members of the holostean actinopterygians. Contralaterally, the retina projects to the preoptic nucleus of the hypothalamus, and, via the medial optic tract, to the dorsal thalamus, medial ventral thalamic nucleus, nucleus pretectalis profundus pars ventralis and pars dorsalis, and the medial portion of the deep layer of the central zone in the optic tectum. The dorsal optic tract projects to the lateral ventral thalamic nucleus, nucleus pretectalis centralis, and the superficial white and gray zone of the optic tectum. The ventral optic tract terminates in the nucleus of the ventral optic tract, the lateral and medial ventral thalamic nuclei, nucleus pretectalis superficialis, nucleus pretectalis centralis, nucleus pretectalis profundus pars ventralis, the basal optic nucleus, and the superficial white and gray zone of the optic tectum. Ipsilateral projections are to similar sites, except for an absence of inputs to the lateral ventral thalamic nucleus from the dorsal tract and to the nucleus pretectalis superficialis, nucleus pretectalis profundus pars ventralis, and the basal optic nucleus from the ventral tract. The presence of ipsilateral retinal projections in gars is compared to their presumed absence in teleosts, and comparisons of retino‐recipient targets in gars are made with teleosts and with non‐actinopterygian vertebrates.
Organization of the tectofugal visual pathway in the pigeon: A retrograde transport study
Authors: Benowitz Larry I. , Karten Harvey J. 
Published: January 2005

AbstractIn birds, superficial laminae of the optic tectum receive a massive retinal input; the tectum in turn projects upon the nucleus rotundus thalami, which then sends its efferents to the ectostriatal core of the telencephalon. To examine the detailed organization of this principal ascending visual pathway, small injections of the marker horseradish peroxidase (HRP) were placed in various sites throughout the ectostriatum (E) or nucleus rotundus (Rt) in pigeons. Analysis of the resulting patterns of retrograde labeling indicates the tectofugal pathway to be comprised of at least five different channels. Cells which lie at various depths in the stratum griseum centrale (SGC) of the tectum project upon distinct subdivisions of nucleus rotundus. Anterior portions of Rt receive input from superficial most cells in the SGC, while medial and more caudal portions of Rt are projected upon by deeper SGC neurons. A ventral subdivision of Rt was found to receive its primary input from two pretectal nuclei. Additional inputs to all portions of Rt arise from nucleus reticularis superior thalami.The various subdivisions of rotundus in turn project upon distinct portions of the ectostriatum. Thus, the segregation between the different input classes into Rt is largely retained at the telencephalic level. In contrast, the nucleus triangularis, a dorso‐medial extension of Rt which receives its input from the deepest of all SGC neurons, sends its efferents to all parts of the ectostriatum.
The effect of age on the reversibility of cellular atrophy in the LGN of the cat following monocular deprivation: A test of two hypotheses about cell growth
Authors: Cragg Brian , Anker Robyn , Wan Yoke Kum 
Published: January 2005

AbstractMonocular closure soon after birth is known to reduce the growth of the deprived cells in the LGN provided that there are competing cells with normal input. When the closed eye was opened and the open eye closed after three or six weeks of monocular closure, the originally deprived cells in the LGN were able to recover their normal size. However, it was found that after 14 weeks of monocular closure there was no recovery.The ability of the initially closed eye to excite cells in the visual cortex is known to depend on the age when eye closure is reversed in a similar manner. Thus the growth of cells in the LGN is correlated with the possession of effective synapses upon cortical cells. This result is compatible with the hypothesis that competition occurs at the cortical level. It is argued that the alternative hypothesis of competition within the LGN predicts reversibility at any age.In some kittens, the closed eye was opened and the opposite optic nerve crushed. Some evidence was then found of structural recovery even after 14 weeks of deprivation. The hypothesis of cortical competition predicts functional recovery in such kittens, but this remains to be tested.
The localization of cholinesterase in the retina of the fetal and newborn guinea pig
Authors: Spira Arthur W. 
Published: January 2005

AbstractRetinae of guinea pigs from the fortieth day of gestation to one day postnatally were processed for the localization of cholinesterases in the electron microscope according to the method of Lewis and Shute (66). Selective inhibition served to distinguish acetylcholinesterase from non‐specific cholinesterase activity. Acetylcholinesterase activity was found initially in small amounts in some regions of the outer plexiform layer at the fortieth day of gestation. At later stages it increased in distribution being observed at some photoreceptor terminals and in non‐synaptic regions of the layer. Activity was less intense initially in the inner plexiform layer but increased rapidly so that by birth it encompassed a majority of processes. Perikarya of horizontal and some amacrine and ganglion cells possessed acetylcholinesterase activity in their nuclear envelope and rough endoplasmic reticulum. The possible role of the enzyme in inhibitory circuits of the fetal retina is discussed.
The olivocerebellar projection in the cat studied with the method of retrograde axonal transport of horseradish peroxidase. VI. The projection onto longitudinal zones of the paramedian lobule
Authors: Brodal A. , Walberg F. 
Published: January 2005

AbstractMicroinjections (30–50 nl) of a horseradish peroxidase (HRP) suspension of 25% (wt./vol.) were made in different folia of the paramedian lobule of cats, and the sites of occurrence of labeled cells in the inferior olive were precisely determined. In each case only a small number of cells are labeled, aggregated in a minute area. The labeled cells are found within three only of the four olivary areas previously determined (Brodal et al., '75) to project onto the paramedian lobule (fig. 1): one area in the rostral half of the medial accessory olive, another in the dorsal accessory olive (except its caudalmost part), and a third in part of the caudal half of the dorsal lamella of the principal olive. Labeled cells were never found in the fourth area, the ventral lamella. A distinct zonal pattern in the projection is demonstrated (figs. 3, 5B): a middle longitudinal zone of the paramedian lobule receives olivary afferents from the area in the medial accessory olive, a medial zone from part of the projection area in the dorsal accessory olive, a lateral zone from part of the projection area in the dorsal lamella. This zonal projection appears to extend throughout the length of the paramedian lobule (the two caudalmost folia could not be studied). The somatotopical pattern in the projections from the accessory olives described previously (Brodal et al., '75) is confirmed. The pattern of a zonal projection obtained with the HRP‐method (fig. 5B) is simpler than that deduced by Armstrong et al. ('74) from recordings of antidromic potentials in the olive (fig. 5A). Concerning main points there is satisfactory agreement.The phenomenon that following microinjections of HRP in superficial parts of the folia labeled cells occur within parts only of the regions of the olive which contain labeled cells following large HRP‐injections in the paramedian lobule is discussed.
The organization of the cerebellorubral projection: An experimental study in the rat
Authors: Caughell K. A. , Flumerfelt B. A. 
Published: January 2005

AbstractThe organization, distribution and extent of the cerebellorubral projection in the rat was investigated employing silver impregnation techniques. Cerebellar lesions of varying size were introduced stereotaxically into the deep cerebellar nuclei in a series of 32 rats and the midbrains were stained with the method of Fink and Heimer. Following large lesions which involved all of the cerebellar nuclei and their emerging fibres, numerous degenerating fibres of passage were observed to course within the brachium conjunctivam, to decaussate at the level of the inferior colliculus, and to enter the ventromedical aspect of the contralateral red nucleus. The red nucleus of the rat consists of a caudal magnocellular portion in which giant and large cells predominate and a rstral parvocellular part consisting mainly of small and medium sized cells. Within the red nucleus, coarse preterminal and terminal degeneration was distributed throughout the magnocellular portion, particularly in relation to the cell bodies and proximal dendrites. Degeneration within the parvocellular part of the nucleus was less abundant, finer in calibre and was parvocellular part of the nucleus was less abundant, finer in calibre and was scattered throughout the neuropil. Following discrete lesions of the nucleus interpositus, preterminal and terminal degeneration was restricted to the magnocellular red nucleus and it was similar in calibre and distribution to that observed in the same area following total lesions. No terminal degeneration was encountered in the parvocellular region at any time following lesions of the nucleus interpositus and only degenerating fibres of passage were seen coursing through the parvocellular region en route to thalamic levels. After lesions restricted to the nucleus lateralis, degenerating fibres were again observed coursing within the brachium conjuctivum and entering the red nucleus. In cases with nucleus lateralis lesions a pattern opposite to that observed following nucleus interpositus lesions was evident. Only passing fibres occurred within the magnocellular region and terminal degeneration was limited to the parvocellular part where it was randomly distributed, moderate in amount and fine in calibre.This investigation has shown that the nucleus in the rat receives a major projection from the contralateral cerebellar nuclei and that a differential distribution of fibres from the nucleus interpositus and the nucleus lateralis terminates within the rubrospinal and rubroolivary portions of the red nucleus respectively.