bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cytology and synaptology of the lateral reticular nucleus of the cat
Authors: Hrycyshyn A. W. , Flumerfelt B. A. 
Published: January 2005

AbstractThe organization of the lateral reticular nucleus (LRN) of the cat was investigated using electron microscopic and Golgi techniques. Golgi‐Cox preparations revealed that the LRN consists of allodendritic and, especially, isodendritic neurons. The latter have been associated with neural centres that have important roles integrating signals from distant sources. Several froms of spines were identified with the Golgi method, and their ultrastructural correlates were determined. Somatic spines resembled stubby protrusions, while dendritic spines, which were usually observed on distal dendrites, appeared as pedunculated spines, recemose appendages and spine‐crowned appendages.Ultrastructural exmaination of this nucleus revealed various synaptic relationships. The majority of the synaptic terminals were small (1.5–2.5 μm in diameter), contained round vesicles and usually contacted dendrites and spines. Other small terminals contained pleomorphic vesicles and contacted distal dendrites and spines. Large terminals (>2.5 μm in diameter) with round or pleomorphic vesicles contacted the somata or proximal dendrites. Three types of “synaptic configurations,” which consisted of discrete aggregations of neuronal processes invested by astrocytic lamellae, were also identified. These structural arrangements likely provide a basis for the integration of inputs to the LRN from spinal and supraspinal centres.
Neuronal and synaptic structure of the dorsal lateral geniculate nucleus in normal and monocularly deprived Macaca monkeys
Authors: Wilson James R. , Hendrickson Anita E. 
Published: January 2005

AbstractThe dorsal lateral geniculate nucleus (dLGN) of Macaca monkeys was studied by Golgi and quantitative electron microscopic (EM) methods to determine if differences in neuronal morphology exist which might correlate with the known physiological separation of X‐type cells into the parvocellular and Y‐type cells into the magnocellular laminae. Monocularly lid‐sutured Macaca monkeys were also studied by quantitative EM methods to compare the synaptic organization within laminae innervated by the deprived and nondeprived retinae.We have divided our sample of Golgi‐impregnated neurons into three groups: Types A, B, and C. Type A neurons comprise the majority of the projection cells and are quite heterogeneous in their overall morphology. Type B neurons have long dendrites with multiple appendages; some have a locally ramifying beaded axon. Type C neurons are characterized by dendrites which are mainly restricted to the interlaminar zones. We found Type A and B neurons in both the parvocellular and magnocellular laminae. The cell bodies of Type C neurons lay within the interlaminar zones or the parvocellular laminae. All three types contributed dendrites to the interlaminar zones. No significant differences in Golgi morphology other than overall size were found in parvocellular or magnocellular laminae that would explain the previously demonstrated electrophysiological differences.Terminal profiles and synapses in the parvocellular, magnocellular, and interlaminar zones were classified and counted using quantitative EM methods. RSD and F terminals were most numerous in all three zones. RLP terminals were rare in the interlaminar zones. A new type of terminal, RMD, was found in the magnocellular interlaminar zones. The laminar and interlaminar zones have the same overall synaptic density, but differed in types of synaptic terminals. The only quantitative difference between any of these regions was in the magnocellular laminae where the counts showed 70% more F terminals per unit area.The same quantitative methods were applied to the laminar and interlaminar zones of dLGNs from monocularly lid‐sutured monkeys. We found no qualitative or quantitative difference between the synaptology of zones receiving input from the deprived retina compared to the open eye retina, nor between any regions of the dLGN in deprived monkeys compared to normal monkeys.
Neuronal organization of the rabbit cochlear nucleus: Some anatomical and electrophysiological observations
Authors: Perry Dennis R. , Webster William R. 
Published: January 2005

AbstractThe cochlear nucleus of the young adult rabbit was studied using both anatomical and electrophysiological techniques. The cytoarchitecture of the cochlear nucleus, as revealed by Nissl‐staining and Bodian's Protargol method, was quite similar to that of the cat. The cell types observed by the Golgi‐Cox method were very similar to those observed in the cat cochlear nucleus. Bushy and stellate cells were predominant in the anterior ventral cochlear nucleus, and multipolar and globular cells were observed throughout the posterior ventral cochlear nucleus, surrounding a region containing mainly octopus cells. The dorsal cochlear nucleus was revealed as a laminated structure with a prominent band of fusiform cells. The polymorphic layers contained varieties of giant neurons similar to those observed in the cat. Units in the cochlear nucleus were classified electrophysiologically, in terms of their discharge pattern, and located histologically. The ventral cochlear nucleus contained mainly “primarylike,” “chopper” and “onset” units, but the dorsal cochlear nucleus contained a greater variety of response patterns. “Buildup,” “pauser” and “chopper” response patterns were predominant, and the dorsal cochlear nucleus also contained more inhibitory units than the ventral cochlear nucleus.Both the types of units observed and their location in each nucleus were very similar to those reported for the cat. Both divisions of the ventral cochlear nucleus and the dorsal cochlear nucleus were found to be tonotopically organized in a dorsal (high frequency) to ventral (low frequency) direction. A trend for an organization in a medial to lateral direction was also apparent, particularly in the dorsal cochlear nucleus.
Morphological analysis of astrocytes in the bullfrog (Rana catesbeiana) spinal cord with special reference to the site of attachment of their processes
Authors: Sasaki Hiroshi , Mannen Hajime 
Published: January 2005

AbstractAn attempt was made to elucidate the morphological reatures of astrocytes in the bullfrog spinal cord by means of a combination of electron microscopy, the Golgi method, and the intravascular dye injection method.Astrocytic somata are densely concentrated both in the wall of the central canal and in its proximity, and diffusely distributed in the intermediate and the ventral part of the gray matter. The most complicated and densest vascular network is found in the dorsal part of the gray matter. There is little correlation between the density of the distribution of astrocytic somata and that of the vascular network.Each astrocyte emits one process and ramifies by repeated bifurcations as it approaches the white matter or enters it. All these branching processes reach the pial surface of the spinal cord (the principal processes). Total rostrocaudal extent of their ramification is within 400 μm. A great number of small lateral offshoots (the secondary processes) arise both from the somata and the principal processes.Electron microscopy of vessel walls and the pial surface revealed that the principal processes attach to the subpial basement membrane with a specialized structure, an electron‐dense layer, while the secondary processes merely surround blood vessels in a mode of juxtaposition.Comparison between amphibian and mammalian astrocytes is made regarding the site of attachment of their processes.
Development of chorda tympani taste responses in rat
Authors: Ferrell M. F. , Mistretta C. M. , Bradley R. M. 
Published: January 2005

AbstractTo learn whether neurophysiological taste responses change during structural development of the gustatory system, we recorded from the chorda tympani nerve in rats aged 7 to 92 days after birth. Chemical stimuli applied to the anterior tongue included four monochloride salts, two acids, sucrose, and urea. Responses to all chemicals were obtained as early as 7 days postnatally. Developmental changes in salt, acid, and sucrose responses were observed. Relative to NaCl and LiCl, NH4Cl and KCl gradually decrease in effectiveness as taste stimuli; or, relative to NH4Cl and KCl, NaCl and LiCl become more effective stimuli. These changes are similar to those observed prenatally and postnatally in sheep. Also, relative to NaCl, citric acid, hydrochloric acid, and sucrose become less effective stimuli; or, NaCl becomes more effective as a stimulus, relative to these acids and sucrose. The period of most rapid functional change overlaps a period of rapid structural change. It seems most reasonable to hypothesize that the altering taste responses reflect developmental changes in receptor membrane composition. Since the taste system is not programmed to respond in a mature manner from the moment function begins, there is ample opportunity for changing taste experience to influence the developing taste system.
Direct and indirect pathways from the amygdala to the frontal lobe in rhesus monkeys
Authors: Porrino L. J. , Crane A. M. , Goldman‐Rakic P. S. 
Published: January 2005

AbstractTo elucidate the anatomical relationships between the frontal association cortex and the limbic system in primates, projections from the amygdala to frontal cortex were studied in the rhesus monkey using retrograde and anterograde tracing methods. Following injections of horseradish peroxidase (HRP) into the orbital prefrontal cortex, the gyrus rectus, the superior frontal gyrus, and the anterior cingulate gyrus of the frontal lobe, labeled neurons were found in the basolateral, basomedial, or basal accessory nuclei of the amygdala. None of these nuclei contained labeled neurons following HRP injections into the principal sulcus or the lateral inferior convexity of the frontal lobe. This selective distribution of amygdala connections was confirmed by injecting tritiated amino acids into the amygdala. Silver grains were present only over the orbital cortex and gyrus rectus on the ventral surface of the frontal lobe and over the superior prefrontal gyrus and anterior cingulate gyrus on the medial wall of the hemisphere, while the dorsolateral prefrontal cortex was free of radioactivity. The isotope injection of the amygdala also revealed a projection to the magnocellular moeity of the mediodorsal nucleus (MDmc) which is known to innervate the same ventromedial regions of the frontal lobe that receive direct connections from the amygdala. Although MDmc and amygdala project to the same cortical regions, their terminal fields are different. The direct amygdala input terminates in layer 1 in orbital cortex and gyrus rectus and layer 2 in the dorsomedial cortex and cingulate gyrus, while the thalamic input is primarily to layer 3 and, in some areas, also to the superficial half of layer 1.These findings indicate that the frontal lobe of rhesus monkeys can be subdivided into two separable cortical regions:(1) A ventromedial region including the anterior cingulate gyrus which receives both direct (amygdalo‐cortical) and indirect (amygdalo‐thalamo‐cortical) input from the amygdala; and (2) a dorsolateral frontal region which is essentially devoid of either direct or indirect amygdalofugal axons. On the basis of its selective relationship with the amygdala, the ventromedial region may be considered the “limbic” portion of the frontal association cortex.
A morphological study of cat dorsal spinocerebellar tract neurons after intracellular injection of horseradish peroxidase
Authors: Randić M. , Miletić V. , Loewy A. D. 
Published: January 2005

AbstractThis work represents an attempt to elucidate structural features of electrophysiologically characterized, individual cat dorsal spinocerebellar tract (DSCT) neurons by using intracellular application of horseradish peroxidase (HRP).Intracellular recordings and HRP injections were made in DSCT neurons of the Clarke's column in cat lumbar (L3) spinal cord. The units were identified by antidromic invasion following electrical stimulation of the ipsilateral dorsolateral funiculus at C1. In addition, sensory inputs to the DSCT neurons were determined by natural (adequate) stimuli applied to the hind limb with intact innervation.The morphological analysis is based on data obtained from 19 well‐stained electrophysiologically identified neurons located in Clarke's column. Thirteen of these units received excitatory sensory inputs from muscle receptors, two were activated by cutaneous afferents only, and four had a convergent (muscle + cutaneous) input. The DSCT‐muscle cells were equivalent to the large Clarke cells (class C of Loewy, '70). Their dendrites were oriented primarily in the rostrocaudal direction (up to 2500 μm) and appeared generally smooth except for some branchlets. In four of these cells, the axon was traced into the lateral funiculus. In light microscopic analysis there was no evidence that axon collaterals arose from these axons during the initial trajectory through the spinal grey matter. The four DSCT‐convergent neurons were similar in shape to the DSCT‐muscle units although they appeared to have somewhat smaller cell bodies. Of the two DSCT‐cutaneous neurons one was found to be of the B type, with the dendritic tree having fewer branches and oriented mainly in the medio‐lateral direction. The other cell, however, turned out to be similar in appearance to the C type Clarke neurons.
Neuronal types in the deep dorsal cochlear nucleus of the cat: I. Giant neurons
Authors: Kane Eileen S. , Puglisi Susan G. , Gordon Beverly S. 
Published: January 2005

AbstractLarge or “giant” neurons (average somatic diameter > 22μm) of the dorsal cochlear nucleus (DCN) have been carefully described in this light (LM) and electron (EM) microscopic study of normal Nissl‐stained and Golgi‐impregnated cat brain stems. These neurons can be roughly classed by somatic shape (width:length ratio = r) as elongate (r < 0.65), ovoid (0.65 < r < 0.75), or spherical (0.75 ≤ r ≤ 1.0) in Nissl‐stained sections. However, orientation and location of somata, size, number, and distribution of basal dendrites and other cytological features seen in Nissl material provided five, easily recognized classes of large neurons: elongate bipolar, elongate multipolar, globular, radiate, and oriented multipolar giant cells. Further cytological details of the dendritic tree and axonal morphology of these neurons, observed in rapid Golgi impregnations of cat and kitten brain stems, extended these descriptive categories of giant neurons. These same deep DCN giant cells were identified in thick plastic sections and in subsequent thin sections. Thin sections showed further neuronal distinctions by relative density of somatic and dendritic synaptic inputs. All giant cells have dense synaptic inputs to basal and primary dendrites but only elongate multipolar and radiate giant cell somata have nearly continuous synaptic coverage of somata. Many axodendritic terminals and some axosomatic endings resemble cochlear endings as identified on fusiform cells of the DCN. Nauta preparations after ipsilateral cochlear ablations have confirmed (1) cochlear input to all giant cell types and (2) different patterns of input to each type. Hence, each giant cell type must process incoming auditory signals, but each cell must receive slightly different primary information. Since some giant cells of each type had observable axons heading into the dorsal acoustic stria, they must all carry encoded primary information to higher auditory centers.
Organization of substance P fibers within the hippocampal formation demonstrated with a biotin‐avidin immunoperoxidase technique
Authors: Vincent S. R. , Kimura H. , McGeer E. G. 
Published: January 2005

AbstractThe distribution of substance P‐containing fibers within the hippocampal formation of the cat was examined using an immunohistochemical approach. A new, indirect immunoperoxidase method based on the high affinity binding of vitamin H (biotin) by avidin was developed to demonstrate substance P‐like immunoreactive fibers. The neocortex contained only occasional single substance P fibers. In contrast, the archicortical structures contained a well organized substance P innervation. The entorhinal area of the parahippocampal gyrus contained a delicate network of varicose axons which appeared to ascend form the subcortical white matter to terminate predominantly in layer II. The subiculum contained a network of positive varicosities throughout the neuropil of both the pyramidal and the molecular layers. These substance P terminals appeared to arise, at least in part, from fibers entering laterally across the angular bundle. Within the ventral hippocampus the substance P innervation was predominantly in the pyramidal cell layer, and was heaviest in field CA3 and weakest in CA1. Some fibers were also observed in strata oriens, lucidum, and radiatum. Occasional varicose fibers could be seen entering the hippocampus from the fimbria. Within the dentate gyrus the substance P fibers were most concentrated in the supragranular layer and among the more superficial of the granule cells. A moderately dense plexus of fibers also occurred in the neuropil of the hilus among the polymorphic cells. In addition, a distinct, narrow band of varicosities was found at the outer edge of the inner molecular layer, while the outer molecular layer did not contain any positive elements.It is concluded that the hippocampal formation receives a distinct, well organized substance P innervation. Substance P fibers appear to enter the hippocampus both laterally across the angular bundle and ventrally through the fimbria. From this detailed examination of the distribution of the substance P fibers within the hippocampus in relation to the other known inputs to this area it is suggested that many of the substance P fibers arise in or, more probably, pass through the septal area to innervate the hippocampus.
Light‐microscopic immunocytochemical localization of tyrosine hydroxylase in prenatal rat brain. I. Early ontogeny
Authors: Specht Linda A. , Pickel Virginia M. , Joh Tong H. , Reis Donald J. 
Published: January 2005

AbstractThe immunocytochemical localization of tyrosine hydroxylase is examined during ontogeny in the fetal rat brain in order to determine the age of first detection and subsequent cellular localization of the enzyme and the developmental characteristics of the immature catecholaminergic neurons. Fetal atlases of the tyrosine hydroxylase‐labeled neurons are presented at embryonic day (E) 12.5, 13.5, and 14.5.Tyrosine hydroxylase is first detected immunocytochemically at E 12.5. At this stage, the labeled neurons have completed final mitosis, but are still migrating and are cytologically immature. Tyrosine hydroxylase can also be detected in axons and axonal growth cones at this stage of development. The age of first immunocytochemical detection of the enzyme precedes the demonstration of catecholamine fluorescence by 1 to 2 days in certain nuclear groups.At later stages of development (E 13.5 and E 14.5), the major groups of perikarya and processes labeled for tyrosine hydroxylase have a distribution similar to that previously described by catecholamine fluorescence. At E 14.5, the perikarya undergo considerable changes in their cytology and exhibit the first dendrites immunocytochemically labeled for the enzyme. The first terminal fields are also detected in the rudimentary caudate‐putamen at this stage.
The distribution of neurons projecting from the retina and visual cortex to the thalamus and tectum opticum of the barn owl, Tyto alba, and the burrowing owl, Speotyto cunicularia
Authors: Bravo Hermes , Pettigrew John D. 
Published: January 2005

AbstractUsing the HRP retrograde transport technique in two different genera of owls (Speotyto and Tyto), we have studied the distribution of neurons projecting to the optic tectum and the visual thalamus. Small injections of HRP were made into these structures from the pial surface after they had been visualized directly by dissection of the overlying bone.In contrast to the findings in mammals, retinal ganglion cells were labeled only in the eye contralateral to the injection site, whether this was in the thalamus or tectum, and the labeled ganglion cells were found on both nasal and temporal sides of the vertical retinal meridian through the fovea. After thalamic injection, labeling was prominent in temporal retina representing the binocular field, temporal to the optic nerve head. Retinothalamic ganglion cells formed roughly concentric lines of isodensity centered on the fovea (Speotyto) or area centralis (Tyto); labeling form thalamic injections involved both large and medium‐sized neurons, but did not involve the smallest nor a conspicuous class of very large neurons. Tectal injections led to prominent labeling along the horizontal streak region, with horizontally elongated isodensity contours in both Tyto and Speotyto; retinotectal ganglion cells were heterogeneous and included a group of very large neurons and another group of small neurons, neither of which was labeled from the thalamus.In the visual Wulst, labeled neurons were confined to the supragranular layers after both tectal and thalamic injections. Corticotectal neurons were found in both ipsilateral and contralateral visual Wulst. They were characterized by large cell bodies and prominent dendrites. Corticotectal neurons were distributed throughout the mediolateal extent of the ipsilateral Wulst and therefore involved both the monocular and binocular representations of the visual field. Corticothalamic neurons, found only in the ipsilateral Wulst, were characterized by smaller cell bodies and fine dendrites. They were confined to the monocular crescent on the extreme medial edge of the Wulst.
The distribution of ganglion cells in the retina of the north american opossum (Didelphis virginiana)
Authors: Rapaport David H. , Wilson Paul D. , Rowe Michael H. 
Published: January 2005

AbstractThe distribution of ganglion cells in the retina of the opossum was determined from whole‐mounted retinae stained with cresyl violet. Isodensity lines were approximately circular with a peak density of 2,000 to 2,700 cells/mm2 in superior temporal retina (area centralis). The total number of retinal ganglion cells was estimated to be 72,000 to 135,000 (mean 101,026) in retinae ranging from 125 to 187 mm2 in total area. Three groups of ganglion cells were distinguished on the basis of soma size and retinal topography. Large cells (24 to 32 μm diameter) were fairly evenly distributed across the retina. Medium cells (12 to 23 μm diameter) were more numerous in the superior temporal quadrant than in other regions of the retina. Small cells (7 to 11 μm diameter) were prominent in all retinal regions, but particularly in nasal and inferior retina. An analysis of topographical differences in soma size distribution suggests that the medium size cells can be further subdivided into small‐medium and large‐medium groups.