bluuebunny/crossref_metadata_2025_split huggingface dataset:
Thalamic projections to visual areas of the middle suprasylvian sulcus in the cat
Authors: Tong Lillian , Kalil Ronald E. , Spear Peter D. 
Published: December 2004

AbstractThe thalamic afferents to two areas of the lateral suprasylvian visual cortex in the cat were studied by using retrograde transport of horseradish peroxidase (HRP). Injections were localized retinotopically with electro‐physiological recording. The posteromedial lateral suprasylvian area (PMLS) of Palmer et al. (78) receives afferents from the pulvinar (P), the posterior nucleus of Rioch (PN), the C‐laminae of the lateral geniculate nucleus (LGNd) and the centrolateral (CL), lateral posterior (LP), medial interlaminar (MIN) nuclei. The anteromedial lateral suprasylvian area (AMLS) receives affer‐ents from CL, P, LP, PN, MIN, and probably from the posterior nuclear group (PO), and the lateral dorsal (LD) and ventral anterior (VA) nuclei.The LP‐pulvinar complex has been divided into four zones on the basis of connectivity: geniculate wing, pulvinar, the lateral division of LP, and the interjacent division of LP (Updyke, '77; Graybiel and Berson, '80; Guillery et al., '80). The locations of labeled cells in the present experiments suggest that both AMLS and PMLS receive afferents from each of the four zones, although differences exist in the strength of the projections.While AMLS and PMLS receive afferents from many of the same nuclei (CL, P, LP, PN, and MIN), differences in their afferents also were noted. These differences are of three types. The first is that some nuclei project to only one of the cortical areas. PMLS alone receives input from the C‐laminae of the LGNd while AMLS alone receives probable input from PO, LD, and VA. The second difference is in the strength of the projection from some nuclei. AMLS receives a stronger projection from CL and P than does PMLS. The third difference concerns the pattern of distribution of neurons that project to each cortical area. Labeled cells in LP are dispersed after an AMLS injection, but are found in clusters or bands after a PMLS injection. Thus our results indicate that the thalamic afferents to AMLS and PMLS are in general similar: however, differences in input to AMLS and PMLS suggest that inputs to PMLS are predominantly visual while AMLS receives a broader spectrum of afferent information.
Distribution of dopamine‐, noradrenaline‐, and adrenaline‐containing cell bodies in the rat medulla oblongata: Demonstrated by the immunocytochemical localization of catecholamine biosynthetic enzymes
Authors: Armstrong David M. , Ross Christopher A. , Pickel Virginia M. , Joh Tong H. , Reis Donald J. 
Published: December 2004

AbstractThe immunocytochemical localization of the biosynthetic enzymes‐tyrosine hydroxylase (TH), dopamine‐beta‐hydroxylase (DBH), and phen‐ylethanolamine‐N‐methyltransferase (PNMT)‐was used to determine the cytological features and precise neuroanatomical location of catecholami‐nergic neurons in the medulla oblongata of rat. Perikarya labeled with TH were detected in two bilaterally symmetrical columns located in the ventrolateral and dorsomedial medulla. The distribution and the number of neuronal perikarya containing TH were the same as those containing DBH, except in the dorsal motor nucleus of the vagus at the level of the area postrema where the number of neurons immunocytochemically labeled for TH was considerably greater than those labeled for DBH. The detection of perikarya which show immunoreactivity for TH, used in the biosynthesis of dopamine, noradrenaline, and adrenaline, but not DBH, which converts dopamine to noradrenaline, suggests the existence of dopamine‐synthesiz‐ing neurons in the medulla.Perikarya labeled with PNMT, used in the biosynthesis of adrenaline, were localized in more restricted regions corresponding to rostral subsets of the dorsal and ventral groups labeled for TH and DBH. Counts of neurons immunpcytochemically labeled for TH or PNMT were obtained in order to determine the relative ratio of neurons which contain the enzymes necessary for the synthesis of dopamine, noredrenaline, or adrenaline at various levels of the medulla. At the most caudal levels no PNMT labeled neurons were detected. Further rostral, PNMT‐labeled neurons were first detected in the ventrolateral medulla. At the level of the area postrema, the number of PNMT‐labeled neurons in the ventrolateral medulla was approximately half of the number of cells showing immunoreactivity for TH. In contrast, few PNMT‐labeled cells were detected in the dorsomedial medulla at the level of the area postrema compared to many neurons labeled for TH. At rostral medullary levels, in both the ventrolateral and the dorsomedial regions, the number of neurons labeled for TH and PNMT was essentially the same. Thus most, if not all, of the catecholaminergic neurons in the rostral medulla have PNMT, necessary for the synthesis of adrenaline.
Golgi studies on Purkinje cell development in the frog during spontaneous metamorphosis. III. Axonal development
Authors: Uray Nándor J. , Gona Amos G. 
Published: December 2004

AbstractThe development and organization of Purkinje cell axons and their collaterals was studied in the bullfrog using the Golgi‐Kopsch method. In the tadpole, axonal collaterals are few and usually unbranched. In the adult, however, intracortical axonal collaterals of Purkinje cells are more numerous, and they form a meager supraganglionic plexus and a more extensive infraganglionic plexus. In contrast to the pattern seen in higher vertebrates, these plexuses have a tendency to be distributed along the length of the cerebellar plate in both tadpoles and froglets. In addition, collateral branches that form intracortical plexuses apparently increase throughout the course of cerebellar development in this species.
Retinal degeneration in the pcd cerebellar mutant mouse. I. Light microscopic and autoradiographio analysis
Authors: LaVail Matthew M. , Blanks Janet C. , Mullen Richard J. 
Published: December 2004

AbstractThe Purkinje cell degeneration (pcd) mutant mouse rapidly loses cerebellar Purkinje cells between 3 and 5 weeks after birth and slowly loses retinal photoreceptor cells during the first year of life. In the present study, the retinal degeneration in the pcd mouse was analyzed by light microscopy and autoradiography throughout the first 15 months of age. By day 25 there is an abundance of pyknotic photoreceptor nuclei and many outer segments are clearly disorganized. Thereafter, as the photoreceptor cells are lost, their outer segments slowly become shorter and more variable in length; this slow change in length is explained by an almost proportional reduction in both rod outer segment renewal and disc shedding rates. At about 2 months of age, the rate of rod outer segment renewal is slightly less than half that in littermate controls, and the number of large phagosomes in pigment epithelial cells during the burst of disc shedding soon after light onset is one‐half or less than that seen in littermate controls. Between 2 and 10.5 months of age, the retina in the inferior hemisphere of the eye shows substantially more‐advanced photoreceptor degeneration than does the superior hemisphere, particularly in the far peripheral retina. A central‐toperipheral gradient of degeneration is conspicuous in the superior hemisphere; a similar but less obvious gradient of degeneration is also seen in the inferior hemisphere of the eye. Loss of photoreceptor cells and their synaptic terminals results in a predictable thinning of the outer synaptic layer. However, the inner nuclear layer shows no measurable thinning and the inner synaptic layer is reduced in thickness by only about 5–15%. Beginning at about 10 months of age, foci of thinned pigment epithelial cells are evident, and by 12 months there is some vascularization of the pigment epithelium by retinal capillaries.
Mesodiencephalic and other target regions of ascending spinal projections in the turtle, Pseudemys scripta elegans
Authors: Kunzle H. , Woodson W. 
Published: December 2004

AbstractAscending spinal projections were investigated in turtle Pseudemys scripta elegans following injections of radioactive amino acids into the spinal cord at various levels. Experiments using S35‐methionine were most successful in demonstrating various mesodiencephalic target areas.Ascending projections from lumbar and cervical segments terminated predominantly in caudal and lateral reticular fields including the perihy‐poglossal complex. These spinal regions also projected for a lesser extent to rostrolateral and caudomedial reticular fields and to the nucleus (n.) raphe inferior. Afferents terminated consistently within the peritoral region, the optic tectal layers, the mesodiencephalic periventricular white matter, and the ovalis complex. Occasional labeling was noted in the diencephalic white matter adjacent to the optic tract, the n. supraopticus, and in the n. commissuralis anterior. Projections to the so‐called rostrolateral perirotundal complex following high cervical injections were less prominent following low cervical and lumbar injections. Cervical afferents terminated in a variable manner in the vestibular complex, the torus semicircularis n. centralis, the mesodiencephalic periventricular gray (griseum centrale, n. intersti‐tialis commissuralis posterior and hypothalamic areas), the n. suprapedun‐cularis, and the n. reuniens.
Modification of visual callosal projections in rats
Authors: Cusick C. G. , Lund R. D. 
Published: December 2004

AbstractThe effects of a variety of developmental manipulations on the distribution of the callosal pathway to visual cortex were examined by using the Fink Heimer technique in adult rats. First, the callosal projections in albino and pigmented rats were compared and found to be similar. The callosal pathway was limited in area 17 to a region adjoining its lateral border with area 18a. Second, dark‐reared rats were found to have normal callosal projections. Third, rats bilaterally enucleated at birth had expanded callosal inputs within area 17. Fourth, monocular enucleation at birth produced an expanded callosal pathway to area 17 contralateral to the enucleation and normal callosal projections to the opposite hemisphere. The expanded callosal inputs after enucleation showed a patchy distribution and usually avoided the most medial part of area 17. Fifth, a reduction in the callosal projections to the area 17/18a border was found after neonatal unilateral optic tract lesions. Sixth, expanded callosal inputs to area 17 were found following unilateral thalamic lesions at birth. The abnormal projection occupied mainly layers IV and III.The results of the different experiments indicate that the detailed distribution of the visual callosal projection within area 17 depends heavily on the organization of the retinogeniculocortical pathways to each hemisphere.
The projections of the lateral geniculate nucleus of the squirrel monkey: Studies of the interlaminar zones and the S layers
Authors: Weber J. T. , Huerta M. F. , Kaas J. H. , Harting J. K. 
Published: December 2004

AbstractAnterograde and retrograde tracing techniques were used to reveal that axons arising from neurons within the interlaminar zones and the S layers of the lateral geniculate nucleus of the squirrel monkey terminate within the supragranular layers of area 17. Specifically, our data indicate that the axons of the neurons housed within the S layers end in a patchlike fashion in cortical layers IIIa and IIIb, while neurons in the interlaminar zones project primarily to layer I. Both pathways may convey W‐cell information from the retina and the superior colliculus to the striate cortex.
Cytoarchitecture and visual receptive neurons in the wulst of the Japanese quail (Coturnix coturnix japonica)
Authors: Watanabe Masami , Ito Hironobu , Masai Hideo 
Published: December 2004

AbstractThe cellular organization of the Wulst was studied in Nissl‐ and Golgi‐stained brain sections in order to identify the visual receptive neurons. Golgi‐impregnated neurons were divided into four types according to their soma size, dendritic configuration, and density of spine distribution. Type I neurons, the largest cells in the Wulst, have long, straight dendrites with many spines. Type II neurons are medium‐sized cells with long, straight dendrites. These dendrites have numerous spines. Type III neurons are medium‐sized or small cells with spine‐free dendrites. Type IV neurons, the smallest cells in the Wulst, have short dendrites with sparse spines. The projections of the nucleus dorsolateralis anterior thalami pars lateralis (DLL) to the Wulst were determined by the Fink‐Heimer method. After lesions of the DLL, degenerating terminals are seen in a dorsolateral portion of the nucleus intercalatus hyperstriatum accessorium where the types II, III, and IV neurons are distributed. Postsynaptic elements to the DLL axons were identified by reconstruction of electron microscopic serial sections. Most of the postsynaptic elements were dendritic spines of the type II and IV neurons and a few were dendritic shafts of the type III neurons.
A developmental study of substance‐P, somatostatin, enkephalin, and serotonin immunoreactive elements in the spinal cord of the North American opossum
Authors: DiTirro F. J. , Martin G. F. , Ho R. H. 
Published: December 2004

AbstractSubstance‐P (SP), somatostatin (SOM), enkephalin (ENK), and serotonin (5‐HT) immunoreactive elements were studied in the spinal cord of the opossum at each 10‐mm snout‐rump (S‐R) length interval between 18 (newborn) and 127 mm (75 days after birth). The opossum is born 12 days after conception and undergoes a protracted postnatal development in an external pouch which makes it a good model for such a study. SP‐like immunoreactivity was detected in the newborn opossum; it was found within fibers located mainly in the dorsolateral marginal zone. SP‐like immunoreactive fibers soon become fairly abundant within presumptive laminae I, II, and X and were scattered within other areas of the spinal gray matter including the intermediolateral cell column. By 30 days after birth (57 mm S‐R length), the adult distribution was established. SOM‐like immunoreactivity was not detected within the spinal cord at birth. However, by postnatal day 5 (24 mm S‐R length) it was present in fibers which were numerous within the marginal zone and present within presumptive laminae I–III as well as in more ventral areas of the gray matter. By approximately postnatal day 30, evidence for SOM immunoreactivity was found within all areas of the spinal gray matter expected from studies of the adult opossum. ENK‐like immunoreactivity was present at birth within fibers of the dorsolateral marginal zone. By postnatal day 30 ENK immunoreactive fibers were found within most of the areas containing them in the adult animal, except for laminae I and II. ENK‐like immunoreactivity was not observed in laminae I and II until approximately postnatal day 50 (84 mm S‐R length). Fibers showing 5‐HT‐like immunoreactivity were remarkably abundant within the cervical marginal zone at birth but sparse at lumbosacral levels. They were found within laminae IV–Xby postnatal day 15 (35 mm S‐R length) and within the intermediolateral cell column by at least day 30. The adult distribution was not present until approximately 50 days after birth when 5‐HT‐like immunoreactivity was found within fibers of laminae I and II. Demonstration of SOM‐, ENK‐, and 5‐HT‐like immunoreactivities in neuronal somata of the spinal cord was age dependent.Our results suggest that axons containing SP, SOM, ENK, and 5‐HT are present within the opossum's spinal cord very early in development and that they grow into specific spinal targets in an orderly sequence.
Developmental relationships between trigeminal ganglia and trigeminal motoneurons in chick embryos. II. Ganglion axon ingrowth guides motoneuron migration
Authors: Moody Sally A. , Heaton Marieta B. 
Published: December 2004

AbstractIn the chick embryo the trigeminal (V) sensory ganglion cells send axons into the metencephalon a few hours before the V motoneurons migrate from the midline to form a lateral nucleus adjacent to the ingrowing sensory axons. This relationship suggests that the ganglion axons may influence the initiation and direction of V motoneuron migration. In the present experiment the development of the ganglion axons was retarded by removing the neural crest anlage of the V ganglion. Subsequently, V ganglion cells which were derived from the ectodermal placode anlage sent axons into the metencephalon up to 2 days later than normal. The lateral migration of the V motoneurons was similarly delayed, commencing only after the central axons from the placodal ganglia penetrated the metencephalon. This study demonstrates that the presence of V ganglion perikarya alone is not sufficient to guide the appropriate migration of V motoneurons. This migration occurs only after the axons from the V sensory ganglion cells have penetrated the brainstem.
Development of order in the rat trigeminal system
Authors: Erzurumlu Reha S. , Killackey Herbert P. 
Published: December 2004

AbstractThe trigeminal system of the rat is characterized by a high degree of order. The pattern of the distribution of vibrissae follicles on the face is replicated at each synaptic station between face and somatosensory cortex (Belford and Killackey, '80). The present study details the development of the trigeminal nerve, its intrinsic organization, and its relationship with its peripheral and central targets. We have observed that at early embryonic ages (E12 and E13) the trigeminal ganglion neurons grow out in straight lines without crossing, and the distance between these neurons and their peripheral and central targets is very short. We have found that fibers reach the periphery before follicle formation is first detectable (E14). At all ages, the trigeminal fibers show a marked tendency to fasciculate. After the development of the pattern of vibrissae follicles on the face, the pattern of fasciculation within the nerve can be clearly related to the rows of vibrissae and the buccal pad. This peripherally related order in the nerve was experimentally verified by injecting horseradish peroxidase into the follicles of individual rows and selectively sectioning portions of the nerve. Further, we provide evidence that the discrete brainstem pattern reflecting vibrissae distribution develops after organization is detectable in the nerve and in a temporal sequence from lateral to medial, which replicates the developmental sequence of vibrissae follicles from ocular to nasal on the face. This sequence is detectable in both the distribution of afferent terminals as measured with succinic dehydrogenase histochemistry and of horseradish peroxidase back‐labeled trigeminothalamic relay cells. We interpret our results as suggesting that a number of factors may play a role in the establishment of specific neuronal topographies in the rodent trigeminal system.
Direct reciprocal connections between the bed nucleus of the stria terminalis and dorsomedial medulla oblongata: Evidence from immunohistochemical detection of tracer proteins
Authors: Sofroniew Michael V. 
Published: December 2004

AbstractConnections between the bed nucleus of the stria terminalis and the dorsomedial medulla oblongata have been examined by immunohistochemical detection of the tracer proteins horseradish peroxidase (HRP) or wheatgerm agglutinin (WGA). Two sets of four rats received 0.2 or 0.4 μl of eithertracer injected into the dorsomedial medulla oblongata, were fixed by perfusion 48 hours later, and were processed for immunohistochemical detection of the tracers. Rats receiving HRP showed only a few single neurons retrogradely labelled in the ipsilateral bed nucleus, and some anterogradely labelled fibers. Rats receiving WGA showed a large number of retrogradely labelled neurons in the ipsilateral bed nucleus. Labelled neurons were most concentrated in a group in the central, dorsal, and lateral aspects of the nucleus at the level of the anterior commissure and just caudal to this. Just ventral to this group was a dense cluster of anterogradely labelled fibers. The retrogradely labelled neurons ranged from 12 to 20 μm in size and were multipolar. These findings indicate that there are direct reciprocal connections between the bed nucleus of the stria terminalis and the autonomic centers of the dorsomedial medulla oblongata and strengthen the concept that this nucleus is involved in forebrain integration of autonomic functions.
Origin of the rubrospinal tract in neonatal, developing, and mature rats
Authors: Shieh Jeng Yung , Leong Seng Kee , Wong Wai Chow 
Published: December 2004

AbstractThis investigation describes the origin of the rubrospinal tract in neo‐natal (1‐10 days old), developing (15‐20 days old), and mature (2‐4 months old) rats studied by using the horseradish peroxidase (HRP) method of tracing neuronal connections. HRP was administered in the cervical or lumbosacral segments of the spinal cord either in the crystal or solution form. The results showed that the rubrospinal tract extended to the lum‐bosacral part of the spinal cord at birth. There appeared to be no difference in the pattern of labelled rubrospinal (RS) neurons following the admin‐istration of HRP in the cervical or the lumbosacral cord segment of the neonatal, developing, and mature rats. In rats of these three age groups, labelled neurons were found bilaterally in the red nucleus, with a contra‐lateral predominance, and they were found in both the parvicellular and magnocellular portions of the red nucleus. There was a somatotopic ar‐rangement in the labelled RS neurons: Those projecting to the cervical cord segments were located in the dorsal and dorsomedial regions of the red nucleus and those projecting to the lumbosacral cord segments were located in the ventral and ventrolateral regions of the nucleus.
Ascending projections to the inferior colliculus following unilateral cochlear ablation in the neonatal gerbil, Meriones unguiculatus
Authors: Nordeen K. W. , Killackey H. P. , Kitzes L. M. 
Published: December 2004

AbstractWe evaluated the consequences of neonatal cochlear destruction upon ascending projections to the inferior colliculi. Unilateral cochlear ablations were performed in both neonatal and adult gerbils. Four to 12 months later, the inferior colliculus (IC) was examined physiologically and injected uni‐laterally with horseradish peroxidase (HRP). The number of labeled cells was determined bilaterally in all three divisions of cochlear nucleus (CN) and in the medial superior olive (MSO). In both experimental groups, trans‐ncuronal changes within the deafferented CN were greater in the ventral divisions than in the dorsal division. On the unoperated side the magnitude of projections from CN to the inferior colliculi was altered in animals le‐sioned as neonates. Following HRP injections into the IC on the unoperated side, the number of ipsi later ally labeled cells in CN (unoperated side) was significantly greater in the neonatal experimental group than in adult ex‐perimental and control animals. These anatomical changes were accom‐panied by increased ipsilaterally evoked excitatory activity recorded in the IC on the unoperated side. Following HRP injections into the IC on the ablated side, the number of contralaterally labeled cells in CN (unoperated side) was significantly reduced in animals lesioned as neonates as compared with control animals. The number of labeled cells in ipsilateral MSO was not significantly different across groups. Our interpretation is that unilat‐eral cochlear ablation in neonatal gerbils results in an increase in the magnitude of ipsilateral projections and a decrease in the magnitude of contralateral projections from CN on the unoperated side to the inferior colliculi. These data suggest that the normal pattern of innervation of the IC results, in part, from interactions among afferent projections.