bluuebunny/crossref_metadata_2025_split huggingface dataset:
The estrogen‐sensitive neural system in the brain of female cats
Authors: Rees Howard D. , Switz Genevieve M. , Michael Richard P. 
Published: January 2005

AbstractEstrogens participate in the regulation of gonadotropin secretion and in the control of sexual and aggressive behavior. To elucidate the neuroanatomical substrate for these actions in the female cat, the topographical distribution of estrogen‐concentrating cells in the brain was studied by autoradiography. One hour after the intravenous injection of 1 mCi (3 μg) of 3H‐estradiol in three adult ovariectomized cats, radioactivity was concentrated in the nuclei of neurons in several brain areas. Within the telencephalon, high concentrations of moderately to heavily labeled cells were found in the lateral and posterior septal nuclei (n.), bed n. of the stria terminalis (medial division), medial and central amygdaloid n., and amygdalo‐hippocampal area. There were also many less strongly labeled cells in the ventral dentate gyrus. Within the diencephalon, many heavily labeled cells were distributed in the medial and periventricular preoptic n., anterior hypothalamic area, and infundibular, ventromedial, and periventricular hypothalamic n. In the brain stem, some labeled cells were located throughout the periaqueductal gray, and in the laminar spinal trigeminal n., n. of the solitary tract, n. incertus, marginal n. of the superior cerebellar peduncle, rostral linear n., and interfascicular n. Although minor differences were noted, the topographical distribution of estradiol‐concentrating cells in the femal cat brain agreed closely with that reported in other vertebrate species.
Ordinal position and afferent input of neurons in monkey striate cortex
Authors: Bullier Jean , Henry Geoffrey H. 
Published: January 2005

AbstractFrom the extracellular recording of single units in the monkey striate cortex and electrical stimulation at two selected sites in the optic radiations it was possible to estimate (1) the ordinal position of striate neurons (i.e., whether they received a monosynaptic, disynaptic or polysynaptic input from the thalamus) and (2) the nature of the afferent input to these neurons (i.e., whether it came from the magnocellular or parvocellular subdivision of the lateral geniculate nucleus (LGN)). Based on receptive field properties six major classes of striate neuron were identified—three which lacked orientation specificity (the ON‐center, the OFF‐center, and the ON/OFF or nonoriented (N‐0) receptive fields) and three with orientation specific responses (the S, the C, and the B categories of receptive field). Units lacking orientation specificity were concentrated in laminae 4A, 4Cβ and 6 while, for the cells with orientation specificity, C cells were found in laminae 4B and 6, B cells in 2/3 and 5, and S cells predominantly in laminae 2/3, 4Cα, and 5.The results of electrical stimulation indicated that cell‐to‐cell transmission time in the monkey striate cortex is 1.5 msec, and latency measures showed that cells with a monosynaptic drive from the thalamus were confined to laminae 4 and 6 while disynaptically driven cells were found principally in upper lamina 4 (4A and 4B). No cell class was identified exclusively with a given ordinal position and there were many types of potential first‐order neurons.The conduction time from one stimulating electrode to the next in the optic radiation was used to identify the afferent input to each striate neuron. The input to color‐coded neurones was found to come exclusively from parvocellular layers while the C cells and two subclasses of the S cell (S2 and S3) were driven predominantly by the magnocellular subdivision. For other cell types (those with ON‐center, N‐0, and S1 receptive fields) the input came from either type of LGN neuron.The laminar distribution of neurons receiving a direct input from the magnocellular and parvocellular streams is in accord with the results of anatomical studies into the site of termination of the LGN input. The cell types receiving these direct inputs vary in the two streams so that the parvocellular input terminates on cells with ON‐center and N‐0 receptive fields in lamina 4Cβ while the magnocellular input goes to cells with S, ON‐center, N‐0, and C receptive fields in lamina 4Cα and the lower part of 4B.Consideration is given to the influence of these results on models for neural processing in monkey striate cortex and a comparison is drawn with the results of similar studies in the cat.
Effects of undernutrition on myelination in rat corpus callosum
Authors: Lai Mabel , Lewis Paul D. 
Published: January 2005

AbstractRats were undernourished by halving the mother's food intake from the sixth day of pregnancy onwards and through lactation. Subsequently, the young animals were maintained up to 48 days on half the normal diet. The effects of this regime of treatment on myelination in the corpus callosum were investigated by light and electron microscopy.In comparison with controls, the percentage of axons myelinated at 15, 21, and 48 days was reduced in undernourished rats. The number of lamellae constituting the myelin sheath was also reduced at 15 and 21 days, but at 48 days no difference was seen between control and treated rats, suggesting that a catch‐up in myelination had occured. A linear relationship between myelin sheath thickness and axonal diameter was observed in both groups of animals. However, a long‐term effect on axonal growth was suggested by findings in the 48‐day undernourished animals; in comparison with controls, axonal diameter was reduced, relative to myelin sheath thickness.
Excitation and inhibition of marginal layer and interstitial interneurons in cat nucleus caudalis by mechanical stimuli
Authors: Hubbard J. I. , Hellon R. F. 
Published: January 2005

AbstractIn cats anesthetized with urethane, the caudal medulla was stabilized in preparation for intracellular recording from interstitial neurons in the descending tract of the trigeminal nerve and from neurons in lamina I of nucleus caudalis. Glass micropipets (10–50 M ohms) were advanced from the surface to a maximum depth of 350 μm. When DC potential shifts occurred, it was found that mechanical stimuli to the face generated bursts of positive‐going spikes, followed in some cases by inhibitory postsynaptic potentials (IPSPs). Subdermal electrical stimulation of the face in each receptive field almost always enabled the same neuron to be driven electrically.Recordings were classified as from primary afferent fibers or from interneurons. Primary fibers had a purely positive spike, with a latency varying by no more than 0.05 msec, and could follow stimulation at 500 Hz. The mean latency for the fibers was 1.87 ± 0.06 msec (n = 75), and their absolute refractory period was 0.42 ± 0.02 msec (n = 36).Recordings were classed as from interneurons if there was an IPSP or the latency was at least 4 msec, with a variation of latency of at least 0.5 msec. Responses thought to be monosynaptically driven had a mean latency of 2.09 ± 0.07 msec (n = 32) and could follow pairs of stimuli at a mean minimum interval of 0.70 ± 0.06 msec (n = 20). Responses thought to be polysynaptically driven had a mean latency of 7.9 ± 1.08 msec (n = 49) and a mean interstimulus interval of 2.96 ± 0.84 (n = 20). Most responses were generated by brushing the face (n = 87), some by pressure on the face (n = 25), and a few by pinching the skin of the face (n = 6).Interneuron responses were most commonly recorded in the first 200 μm of the descending tract, and this position was confirmed by the injection of pontamine sky blue and the examination of frozen sections. The recordings were thought to be from dendrites of marginal and interstitial cells or the somas of interstitial cells.The IPSPs which followed spike potentials could only follow stimuli at 10 Hz or less. The failure appeared to be at a primary afferent synapse upon an inhibitory interneuron.Collision tests between mechanically evoked and electrically evoked responses showed long‐lasting inhibition of the response to electrical stimulation after collision. Presynaptic inhibition exerted on the primary afferent excitation was suggested as the explanation.
Normal dendritic morphology of frog spinal motoneurons: A Golgi study
Authors: Bregman Barbara S. , Cruce William L. R. 
Published: January 2005

AbstractNormal dendritic morphology of frog (Rana pipiens) lumbar motoneurons was studied using Golgi silver impregnation. Branching characteristics and quantitative measurements of dendrites were obtained using computeraided serial reconstruction of a typical lumbar motoneuron over seven adjacent 80‐μm transverse sections. Dendrites were classified based upon site of dendrite origin from the soma and distribution of the dendritic array within the spinal cord.Eight possible sites of dendritic origin from the soma were identified. Two dendrites, D1 and D2, are planar dendrites which arise from the dorsal aspect of the soma. They are moderately complex, reaching branch order 5–6, and are oriented predominantly in the transverse plane. Input to these dendrites is primarily segmental via dorsal root projections.Three dendrites, D3, D4, and D5, arise laterally from the soma and extend through the lateral funiculus toward the subpial region. Two dendrites, D6 and D7, arise ventrally. D6 extends ventrolaterally and is a simple dendrite reaching branch order 3–4. D7 aborizes extensively in the ventral funiculus and in the central gray, reaching a branch order of 8–9. This dendrite extends rostrally and caudally over a distance of at least 560 μm. Another dendrite (D8) arises from the medial aspect of the soma and projects toward the central canal.Four sites (D1, D2, D6, and D7) almost invariably give rise to dendrites. Dendrites arise at D4 in 66% of the cells examined. Dendrites are found at D3, D5, and D8 much less frequently (6–21%). Total dendritic length (12,043 μm) and lengths of the individual dendrites, branch length versus branch order, and number of branches at increasing radii were examined, and Sholl analysis was performed.
The Purkinje neuron: I. A Golgi study of its development in the mouse and in culture
Authors: Hendelman W. J. , Aggerwal A. S. 
Published: January 2005

AbstractThe development of the Purkinje neuron was studied in organotypic culture and compared to that occurring in the intact animal, using a modified Golgi‐Cox method. The post‐natal sequence of development in the intact animal occurred in five distinct stages beginning with (1) an immature state (0–3 days), (2) a stage of perisomatic dendritic processes (4–6 days), and then (3) a stage characterized by the presence of spines on the soma region (7–10 days). This stage of somatic spines has not been delineated previously in Golgi studies of the Purkinje cell during its development. There was no evidence that the lateral somatic processes resorb; rather they continue to grow and develop into dendritic branches. It is proposed that by a process of perikaryal translocation, the soma region becomes transferred “downward,” resulting in an elongation of the primary, apical dendrite (stage 4, 11–14 days). Beyond 15 days (stage 5) the dendritic branches grow to the pial surface and the neuron has its full complement of secondary, tertiary, and spiny branches. In culture, the development parallels that occurring in the intact animal during the first 10 days (stages 1, 2, 3) despite the absence of extracerebellar afferents and the special conditions of the culture. However, there is an overall absence of lamination of the cortex, the Purkinje neurons do not align, and the development process is modified because of the failure of the process of perikaryal translocation in culture. The resultant mature neuron has an altered morphology characterized by the presence of several dendrites and spines attached to the soma, and also lacks the complete development of the smaller dendritic branches.
Development of excitatory innervation in the lobster claw closer muscle
Authors: King J. A. , Govind C. K. 
Published: January 2005

AbstractThe development of excitatory innervation to the claw closer muscles of 1st (larval), 4th (juvenile), and adult stage lobster was examined by thin serial section electron microscopy. This was possible since neuromuscular terminals of the excitatory axon are distinguishable from those of the inhibitory axon by the shape of their synaptic vesicles in all three stages. In the adult cutter claw closer muscle, innervation of a dorsal and a ventral fiber which is supplied by the fast closer excitor (FCE) and slow closer excitor (SCE) axons respectively, was qualitatively as well as quantitatively similar. Consequently no attempt was made to distinguish between innervation by FCE and SCE axons in the subsequent analysis of 1st, 4th, and adult stage claw closer muscles. Excitatory innervation in the 1st larval stage is limited to four discrete locations in the entire cross‐sectional area of the closer muscle. It subsequently spreads to each individual muscle fiber in the adult, thus demonstrating the tremendous proliferation of innervation during development. Concomitantly the mean size of synapses increases significantly from the 1st stage to the 4th stage to the adult lobster. This increase in synaptic size may occur by both the fusion and enlargement of existing smaller synapses. In contrast, the mean size of presynaptic dense bars and their mean number per synapse remained fairly constant in each of the 1st, 4th, and adult stages. However, a relatively greater proportion of adult synapses possessed two or more dense bars compared to their larval and juvenile counterparts. Development of innervation of the lobster claw closer muscle therefore consists of a substantial proliferation of axonal tissue and enlargement of synaptic size.
Organization of motor pools in the chick lumbar lateral motor column
Authors: Hollyday Margaret 
Published: January 2005

AbstractMotor pool positions for individual leg muscles were mapped in hatched chicks using intramuscular injections of HRP. Several leg muscles were also mapped in stage 38 (12‐day) embryos. The results indicate that an adult map is formed by stage 38.The adult motor pool map can be viewed as being composed of two maps, one for muscles derived from the embryonic ventral muscle mass, the other for muscles derived from the dorsal mass. Each of these maps is a continuous, although distorted, representation of muscle precursor position on the original sheets of dorsal and ventral muscle mass. The developmental implications of these findings are discussed.
The afferent ganglion cells and cortical projections of the retinal recipient zone (RRZ) of the cat's ‘pulvinar complex’
Authors: Leventhal Audie G. , Keens Jeremy , Törk Istvan 
Published: January 2005

AbstractA retino‐pulvinar projection in the cat was confirmed using anterograde (autoradiography) and retrograde (horseradish peroxidase (HRP) tracing techniques. The part of the ‘pulvinar complex’ receiving retinal afferents is referred to as the retinal recipient zone (RRZ). The cortical projections of the RRZ were studied by injecting HRP into different cortical areas. The retrograde labeling of the cell bodies and dendritic fields of the retinal ganglion cells projecting to the RRZ was accomplished by injecting HRP electrophoretically into the RRZ.Our results indicate that the RRZ projects to areas 19 and the lateral suprasylvian area (LS) but not to areas 17 or 18. Virtually all RRZ cells, including those that project to the cortex, are small (10–20 μm in diameter); they are the same size as the relay cells of the parvocellular C laminae of the lateral geniculate nuclear complex (LGNd) that project to areas 19 and LS.The majority of the ganglion cells projecting to the RRZ had medium‐sized somas (15–25 μm in diameter), large (up to 800 μm in diameter), diffuse dendritic fields with a characteristic morphology, and appeared different form the alpha, beta, gamma, and delta cells of Boycott and Wässle (′74). These cells provide evidence for another morphological class of ganglion cells, termed epsilon cells.Our results suggest that the RRZ relays the activity of specific types of retinal ganglion cells to extrastriate visual cortex and, thus, functions in parallel with the different subdivisions of the LGNd.
Fine structure and synaptic connections of the common spiny neuron of the rat neostriatum: A study employing intracellular injection of horseradish peroxidase
Authors: Wilson Charles J. , Groves Philip M. 
Published: January 2005

AbstractMedium‐sized spiny neurons of the rat neostriatum, identified by intracellular injection of horseradish peroxidase, were examined at both light and electron microscopic levels. These neurons were characterized by their heavy investment of dendritic spines, beginning about 20 μm from the soma and continuing to the tips of the dendrites. Their axons arose from the soma or from a large dendritic trunk very near the soma, and tapered rapidly to form a main axonal branch from which arose several smaller initial collaterals. These arborized extensively throughout an area of about the same size as, and highly overlapping with, the dendritic field of the cell, while the main axon could be followed for distances of up to 1 mm in the direction of the globus pallidus. Three major synaptic types were seen in contact with spiny neurons.Boutons containing small round synaptic vesicles formed synapses exclusively with spiny regions of the dendrites, and most of these were axo‐spinous. Small, very pleomorphic synaptic vesicles characterized a second bouton type of unknown origin, which made contacts with somata, initial segments, and dendrites, but not dendritic spines. Boutons containing large pleomorphic synaptic vesicles had the most widespread distribution, contacting all regions including dendritic spines. Spines receiving these contacts also were postsynaptic to boutons containing small round vesicles. Axon collaterals of spiny cells formed synapses with large pleomorphic vesicles and made synapses with somata, initial segments of axons, dendrites, and dendritic spines of striatal neurons, including other spiny cells.
Central myelin in the mouse mutant shiverer
Authors: Rosenbluth J. 
Published: January 2005

AbstractThe Spinal cord, optic nerves, and cerebellum of the mouse mutant Shiverer were examined by electron microscopy of thin sections. Although central nervous system myelin in grossly deficient in amount, one of its basic structural elements are missing. Regions of compact myelin cat be found composed of several layers of alternation major dense lines and intermediate lines repeating with normal periodicity. The “radial component” consisting of periodic thickenings of the intermediate line aligned through several lamellae was also identified. Axoglial junctions characteristic of the type found in paranodal regions are present in greater than normal numbers but occur in aberrant locations. Myelin sheaths have markedly reduced numbers of lamellae, which often contain cytoplasm terminate in cytoplasmic “loops” within and around myelin sheaths, and do no completely encircle axons. In addition, membranous debris appears within neuronal and glial profiles, suggesting some degree of myelin breakdown. Thus, the protein lacks in this mutant appear not to be associated with discrete deficiencies of specific structural components but rather with a variety of quantitative changes and irregularity of form.
A specialized type of neuron in the visual cortex of cat: A Golgi and electron microscope study of chandelier cells
Authors: Fairén A. , Valverde F. 
Published: January 2005

AbstractThe axonal arborization of chandelier cells is characterized by its conspicuous, vertically oriented, bouton aggregates. The efferent synaptic relationships established by these terminal formations were investigated by electron microscopy of Golgi preparations after gold toning and deimpregnation. In all cases examined form layers II and III of cat areas 17 and 18, the terminal formations, here denominated specific terminal portions (stp), make symmetric synapses upon axon initial segments of pyramidal neurons. Some identified stp's were reconstructed from ultrathin serial sections with the aid of a microcomputer‐based system, and the number of synaptic contacts established on axon initial segments was evaluated. No evidence was found that parts of the axonal tree other than stp's also engage in synaptic contacts.Specific terminal portions are rather variable in complexity. However, the synaptic contacts they engage in are constant and the complexity of stp's from the same axonal arborization varies. It is, therefore, clear that all stp's are terminal axonal formations of a unique, specialized type of neuron.Computer techniques and conventional Golgi observations were used to study further details of chandelier cell morphology. Axonal plexuses are preferentially, although not exclusively, local and distribute within spheric, ovoid, or disk‐shaped spaces In most chandelier cells, the main axonal trunk descends to the white matter, where we have been unable to follow it further.
An EM analysis of the synaptic connections of horseradish peroxidase‐filled stalked cells and islet cells in the substantia gelatinosa of adult cat spinal cord
Authors: Gobel Stephen , Falls William M. , Bennett Gary J. , Abdelmoumene Mohammed , Hayashi Haruhide , Humphrey Emma 
Published: January 2005

AbstractTwo major interneurons of the outer part of Rexed's layer II (IIa) were impaled with microelectrodes, had their primary inputs characterized, and were subsequently filled with horseradish peroxidase. Their fine structural characteristics and synaptic connections were then analyzed electron microscopically. Two islet cells, whose rostrocaudally oriented dendrites were largely confined within layer IIa, received primary input form small myelinated axons. A stalked cell, whose cell body was situated on I/II border had a cone‐shaped dendritic arbor which traversed layer IIa as well as the inner part of Rexed's layer II (IIb) and rostrocaudal dendritic branches which ran for part of their course along the I/IIa border. It received primary input from small myelinated as well as form unmyelinated axons. Both cell types received asymmetrical axodendritic synapses from primary endings in layer IIa and IIb glomeruli and widely separated symmetrical axodendritic synapses from small nonprimary endings outside of glomerli.The presence of aggregates of synaptic vesicles in the dendrites of the layer IIa islet cells but not in the staked cell dendrites constitutes the major fine structural difference between these interneurons. Islet cell dendtrites from symmetrical synapses on several different kinds of neural processes. They usually send either a single type 2 spine (spines which contain synaptic vesicles) or dendtritic shaft into layer IIa and IIb glomeruli, where they form dendrodendritic synapses on adjacent type 1 spines (spines without synaptic vesicles) and on other small dendritic shafts. Some islet cell type 2 spines also form dendroaxonic synapses on the primary endings.Outside of the glomeruli, islet cell dendrites also form dendrodendritic synapses on type 1 spines and different sized dendritic shafts. They often approach other dendritic shafts. They often approach other dendritic shafts forming small bundles of dendrites in which they are reciprocally linked by dendrodendritic synapses to other synaptic vesicle‐containing dendrites. At bead‐like enlargements of their dendritic shafts and along some of the shafts of unmyelinated axons. The unmyelinated axon of the islet cell forms symmetrical synapses on layer II dendritic shafts and spines outside of glomeruli. The role of the layer IIa islet cell as an inhibitory interneuron is discussed.