bluuebunny/crossref_metadata_2025_split huggingface dataset:
Auditory pathways to the cortex in Tupaia glis
Authors: Casseday J. H. , Diamond I. T. , Harting J. K. 
Published: January 2005

AbstractThe auditory system of the tree shrew, Tupaia glis, was investigated by identifying axonal degeneration after lesions of the lateral lemniscus, the inferior colliculus, the medial geniculate nucleus and the auditory cortex. The results show that the lateral lemniscus projects to the central nucleus of the inferior colliculus which in turn projects principally to the ventral division of the medial geniculate nucleus but to a lesser extent to the magnocellular division of the medial geniculate nucleus. The final step in the pathway to the cortex is achieved by a projection from the ventral division to the fourth layer of auditory koniocortex. There appear to be several auditory pathways parallel to this primary path. The lateral lemniscus projects to the dorsal division of the medial geniculate nucleus; the deeper layers of the superior colliculus project to the posterior nucleus; and both the dorsal division and the posterior nucleus project to the belt caudal to auditory koniocortex. The caudal division of the medial geniculate nucleus may constitute a relay in still another path from the pericentral division of the inferior colliculus. Finally, the magnocellular division also appears to be distinct insofar as its cortical projections are confined chiefly to the deeper layers. A comparison between the tree shrew and the cat reveals a similar organization in the two species. In the cat the starting point for understanding the organization of the several auditory pathways is the distinction between a core cortical zone which corresponds to koniocortex and to AI and a peripheral belt. The core receives essential projections from the ventral division; the belt receives sustaining projections from the cell groups which surround the ventral division. It is reasonable to hypothesize that this difference between the core and the belt is characteristic of all mammals.
On the striate area of the human isocortex. A golgi‐ and pigmentarchitectonic study
Authors: Braak Heiko 
Published: January 2005

AbstractThe distribution pattern of the pigment in various layers of the primary visual cortex of man is described by means of a method for the stereomicroscopical demonstration of neurolipofuscins in sections up to 1,000 μm thick.This paper presents the striate area as being composed of 12 cellular layers, which can be clearly delineated by a successive examination of both the Nissl and the pigment preparations.Layers I, II, and III resemble more or less the corresponding laminae of other isocortical fields. The pyramids within the deep portion of layer III are unusually small and additionally are intermingled with thorny stellate cells which are a characteristic component of layer IV. Accordingly, this band of cells is called IIIc–IVa. The subjacent layers IVb and IVcα are poorly pigmented. In Nissl‐preparations layer IVb, which contains only a few cells, is followed by a broad band of cells tightly packed together, which includes layers IVcα, IVcβ, IVd, and Va. These layers cannot be reliably delineated in Nissl‐preparations but appear in pigment preparations as distinct and sharply limited laminae. Particularly, layer IVcß, which is built up by minute thorny stellate cells, is marked by coarse and intensely stained lipofuscin granules, whereas IVd is mainly populated by minute pyramids which are almost devoid of pigment deposits. A remarkably narrowed layer Va, the pyramids of which store a medium number of lipofuscin grains, completes this series (IVcα, IVcβ, IVd, Va). The cell‐sparse layer Vb is almost devoid of pigment granules. Layer Via has specialized pyramidal cells containing finely grained pigment. The relatively broad layer VIb shows loosely arranged cells poorly endowed with lipofuscin granules.
Topographic organization of the projections from the entorhinal area to the hippocampal formation of the rat
Authors: Steward Oswald 
Published: January 2005

AbstractThe present study re‐examines, with autoradiographic methods, the pattern of termination of fibers originating from various medio‐lateral divisions of the entorhinal cortex on dentate granule cells and on hippocampa pyramidal cells of the rat. Entorhinal fibers were found to distribute in a proximodistal gradient along the dendrites of dentate granule cells, with afferents from the medial entorhinal area terminating in the innermost portion of the entorhinal synaptic field, afferents from the lateral entorhinal area terminating in the most superficial portions of the entorhinal synaptic field, and intermediate medio‐lateral locations in the entorhinal area terminating in intermediate loca tions in the entorhinal synaptic zone. A similar graded pattern of termination of medial and lateral entorhinal fibers was apparent in the very slight crossed projection of the entorhinal area to the contralateral dentate gyrus. In addition, a comparable gradient in the pattern of termination of entorhinal fibers was evident in the entorhinal projection field in the distal dendritic regions of the pyramidal cells of regio inferior of the hippocampus proper.Entorhinal projections to regio superior were, however, organized in quite a different fashion. In this zone, there was no evidence of a proximo‐distal gradient in the patterns of termination of medial and lateral entorhinal areas along the dendrites of regio superior pyramidal cells. Rather, the medio‐lateral organization was in a longitudinal dimension, with medial entorhinal afferents terminating in the portions of regio superior near the CA1‐CA2 transition, and lateral entorhinal afferents terminating furthest from the CA1‐CA2 transition, immediately adjacent to the CA1‐subicular transition, and in the molecular layer of the subiculum proper. A comparable longitudinal organization of entorhinal projections to regio superior was also evident in the zones of termination of the crossed temporo‐ammonic tract, contralateral to the injection. These results demonstrate a heretofore unrecognized complexity in the patterns of projection of the entorhinal area to the hippocampal formation, and illustrate that the entorhinal cortex cannot be divided into only two discrete divisions on the basis of the pattern of projection.
Involvement of the avian hypothalamus in defensively conditioned heart rate change
Authors: Cohen David H. , Macdonald Robert L. 
Published: January 2005

AbstractHypothalamic involvement in visually conditioned heart rate change (established by pairing light and foot‐shock) was studied in 128 pigeons by evaluating conditioning performance following lesions of various hypothalamic areas. Extensive destruction of the posterior hypothalamus severely impaired development of conditioned heart rate change. Anterior hypothalamic lesions also produced serious deficits, though not as severe as following posterior hypothalamic damage. Partial posterior hypothalamic, unilateral and tuberal lesions produced only minor to moderate deficits. The critical locus for profound impairment of conditioned response development appeared to be the medial hypothalamus, and it is suggested that more specifically it is the terminal field of the archistriatal projection upon the medial hypothalamus. It is concluded that the medial hypothalamus is essential for the development of defensively conditioned heart rate change, and based on previous findings it is suggested that the critical descending pathway for expression of this conditioned response involves the archistriatal projection upon the medial hypothalamus and subsequently a polysynaptic pathway through the ventral brainstem.
Afferent fibers in the substantia gelatinosa of the adult monkey (Macaca mulatta): A Golgi Study
Authors: Beal John A. , Fox Clement A. 
Published: January 2005

AbstractIn horizontally and sagittally sectioned Golgi preparations of the adult monkey spinal cord the afferent fibers in the substantia gelatinosa(laminae II and III of Rexed, '52) were studied with the hope of finding clues that would make it possible to correlate them with the afferent fibers that Ramón y Cajal ('09) traced from the white matter into the substantia gelatinosa in Golgi preparations of the newborn cat.Throughout the substantia gelatinosa there are fibers with fine terminal branches, bearing small “bouton en passant” endings. These fine terminal branches and the collaterals of the axons of the neurons in the substantia gelatinosa are similar; hence, the fine terminal branches are interpreted as the terminals of the proprius bundles generated by the axons of the neurons in the substantia gelatinosa. Also, there are fibers in lamina II that can be followed for relatively long distances(900 microns) before they are cut off in section. They have collaterals bearing large irregular endings, which usually consist of several or more elongated swellings connected by constricted regions. Some of these endings have holes within them and their surfaces have prominent indentations.The fibers with fine terminal branches and the fibers with large irregular endings are interpreted here as the two varieties of fine or superficial collaterals of the substance of Rolando described by Ramón y Cajal('09).The most elaborate afferent formations in the present material are found in horizontal sections. They are designated “confined ansiform axonal complexes” and are confined to elongated, oblong blocks of substantia gelatinosa that approximate each other in length, width and depth. Their branches, running rostrally and caudally, loop back and forth, interweave in an intricate pattern and bear large synaptic endings. because these formations are elaborate and because their parent fibers and initial branches are thicker in lamina III than they are in lamina II, these complexes are interpreted here as the large or deep collaterals of the substance of Rolando described by Ramón y Cajal('09). Considering their shapes, sizes and surface contours, it is probable that the large endings on the ansiform axonal complexes and the large irregular endings on the long fibers in lamina II are the central terminals in the glomeruli of the substantia gelatinosa that have been revealed by electron microscopy.Finally, there are fine collaterals from fibers in Lissauer's fasciculus which distribute exclusively to the marginal zone (lamina I) of the dorsal horn. Their endings are ovoid or bulbous and are almost uniformly approximately 2 microns in diameter. Undoubtedly, these collaterals are the marginal collaterals Ramón y Cajal ('09) demonstrated in Ehrlich's methylene blue preparations of the 8‐day old cat.
Regeneration of retinal axons into the goldfish optic tectum
Authors: Murray Marion 
Published: January 2005

AbstractThe growth of regenerating retinal axons into the central portion of the optic tectum of adult goldfish was examined with the light and electron microscopes. Optic tracts were cut and, two days to five months later, the animals were perfused and the tecta prepared for microscopy. Regenerating axons first reached central regions of the tectum seven to ten days postoperatively. Regenerating axons appear in very large numbers and travel in fascicles in the stratum opticum (SO) and in the adjacent neuropil, the stratum fibrosum et griseum superficiale (SFGS). In the SO, the fascicles are bordered by glial cells and degenerating debris. Within the SFGS, however, the fascicles do not seem to be similarly associated with glial cells and degenerating debris. The youngest regenerating axons are very slender processes, containing microtubules but few or no neurofilaments or dense granular material. By 10 to 14 days postoperatively, neurofilaments can be seen and, in addition, large numbers of vesicles with dense cores appear. The vesicles with dense cores increase in numbers until about 28 days postoperatively and then become quite rare. That vesicles with dense cores were seen in regenerating axons in both SO and SFGS during the period of growth into the tectum but were not seen in axon terminals at any time, suggests that they may be concerned with axon elongation. During the period one month to five months postoperatively, the regenerating axons gradually increase in diameter but do not reach preoperative sizes, suggesting that the regenerative changes may still be occurring. Remyelination is delayed and proceeds slowly. Many axons remain unmyelinated for as long as five months postoperatively.
Trigeminal projections in snakes possessing infrared sensitivity
Authors: Schroeder Dolores M. , Loop Michael S. 
Published: January 2005

AbstractThe first order projections of the trigeminal nerve were studied in four species of snakes, three of which are infrared sensitive, utilizing silver degeneration and cobalt iontophoresis techniques. The trigeminal nerve projected ipsilaterally to a main sensory nucleus, descending spinal nucleus, ventral trigeminal field and solitary nucleus with a contralateral projection to the base of the descending spinal nucleus in all four species. A major additional projection to the lateral nucleus of the trigeminal was present in all three infrared sensitive species but absent in the other. Iontophoresis of cobalt chloride into a trigeminal branch composed entirely of infrared sensitive fibers and into a trigeminal branch containing no infrared fibers indicated that the lateral nucleus of the trigeminal nerve was the sole first order target of the infrared system.
Projections of the globus pallidus and adjacent structures: An autoradiographic study in the monkey
Authors: Kim Ronald , Nakano Katsuma , Jayaraman A. , Carpenter Malcolm B. 
Published: January 2005

AbstractBecause the globus pallidus gives rise to the principal efferent system of the corpus striatum and is traversed by several fibers systems, attempts were made to study the projections of its cells by autoradiographic technics. Tritiated amino acids (L‐leucine, L‐proline and L‐lysine) were injected into: (1) the medial pallidal segment (MPS), (2) the MPS and the substantia innominata (SI), (3) portions of the MPS and the lateral pallidal segment (LPS) and (4) parts of the putamen.Cells labeled by injections of the MPS transported isotope to thalamic nuclei (ventral anterior, VApc, ventral lateral, VLo and VLm, and the centromedian, CM), the pedunculopontine nucleus (PPN), and the lateral habenular nucleus (Hbl). Labeled cells of the MPS and SI transported isotope to: (1) thalamic nuclei (VLo, VLm and CM), (2) PPN, (3) Hbl, (4) lateral and posterior regions of the hypothalamus, and (5) extensive dorsal regions of the substantia nigra (SN). Comparisons of label transported from uptake of isotope by cells of the MPS, and cells of both pallidal segments, suggest that the LPS projects fibers only to the subthalamic nucleus (STN). Not all regions of the STN appear to receive fibers from the LPS. Selectively labeled neurons of the putamen transport isotope to broad regions of both pallidal segments and to the pars reticulata of the SN.This study suggests that cells of the MPS project profusely and topographically to: (1) the rostral ventral tier thalamic nuclei (VApc, VLo and VLm), (2) lateral portions of CM, and (3) the PPN. Fibers of the lenticular fasciculus appear to terminate preferentially in VLo. Cells in sublenticular portions of SI, and those extending into the medullary laminae of the pallidum, appear to project to: (1) HBl via the stria medullaris, (2) the pars compacta of SN, (3) lateral and posterior regions of the hypothalamus, and (4) the so‐called nucleus of the ansa lenticularis. Some fibers from cells of SI appear to join the dorsal stria terminalis, but none enter the inferior thalamic peduncle and none project to any part of the dorsomedial nucleus of the thalamus.
Areal and laminar distribution of some pulvinar cortical efferents in rhesus monkey
Authors: Trojanowski John Q. , Jacobson Stanley 
Published: January 2005

AbstractThe areal and laminar distribution of the cortical efferents of the medial, lateral and inferior pulvinar nuclei (PM, PL and PI respectively) were determined in rhesus monkey using autoradiography and Horseradish Peroxidase (HRP). The autoradiographic data indicated that: areas 8a, 45 and 46 on the convexity and 11 and 12 on the orbital surface of the frontal lobe received projections from PM; areas 20, 21 and 22 in temporal lobe received projections from PM primarily with caudal‐medial parts of PM projecting to more rostral‐dorsal parts of temporal lobe and rostral‐lateral parts of PM projecting to more caudal‐ventral parts of temporal lobe but PL also sends some efferents to caudal temporal lobe; areas 5 and 7 in parietal lobe and 18 and 19 in occipital lobe received projections primarily from the region in pulvinar comprising PL and PI with the more ventral parts of this region projecting to the ventral‐lateral parts of occipital lobe and the more dorsal parts of this region projecting to the more dorsal‐lateral and medial parts of parieto‐occipital cortex and with PM contributing slightly to these projections rostrally.The autoradiographic information on the pulvinar projections to frontal lobe and temporal pole was supplemented by data derived from cortical HRP injections. These indicated that although only PM of the pulvinar subnuclei projected to these regions, three other caudal thalamic structures, i.e., medial dorsal nucleus, nucleus limitans and suprageniculate nucleus also projected to these regions raising some questions about the identity of the densocellular part of the medial dorsal nucleus which has also been considered to be part of pulvinar.The laminar distribution of pulvinar cortical efferents was uniformly similar regardless of the pulvinar recipient area examined. Elevated numbers of silver grains were observed over all cortical layers, but the silver grains were densest over the deep parts of layer III.The thalamic reticular nucleus was the only diencephalic structure observed to receive projections from pulvinar and it did so from PM, PL and PI.The pulvinar's efferents are to homotypical rather than heterotypical cortex and its connections are most extensive with cortex rather than with subcortical structures.
Growth of the adult goldfish eye. II. Increase in retinal cell number
Authors: Johns Pamela Raymond , Easter Stephen S. 
Published: January 2005

AbstractThe retinas of adult goldfish, one to four years of age, 4–23 cm in length, were examined with standard paraffin histology to determine if new cells were being added with growth. Retinal cell nuclei were counted and the area of the retina was measured. An analysis of cell densities in various regions throughout the retina showed that the cells are distributed nearly homogeneously. The density (No./mm2 of retinal surface) of ganglion cells, inner nuclear layer cells and cones decreases with growth, but the density of rods remains constant. Thus the rods account for a larger proportion of the cells in larger retinas. The total number of cells per retina increases: the ganglion cells from 60,000 to 350,000; the inner nuclear layer cells from 1,500,000 to 4,000,000; the cones from 250,000 to 1,400,000; the rods from 1,500,000 to 15,000,000. This increase in the number of retinal neurons implies the formation of even more new synapses, and suggests the adult goldfish retina as a model for both neuro‐ and synaptogenesis.
Subdivisions of the auditory cortex of the cat: The retrograde transport of horseradish peroxidase to the medial geniculate body and posterior thalamic nuclei
Authors: Winer Jeffery A. , Diamond I. T. , Raczkowski Denis 
Published: January 2005

AbstractEach subdivision of auditory cortex was injected with horseradish peroxidase (HRP). The amount of HRP injected was varied with the result that in some cases the diffusion of HRP was restricted while in other cases, HRP diffused over an entire cortical subdivision and encroached on adjacent subdivisions. In the case of restricted diffusion only a relatively small number of thalamic cells were “labelled”; in the case of extensive diffusion many times that number of cells were labelled. Whether relatively few or many cells, the distribution of labelled cells fell into distinctive patterns. Each pattern consisted of a focus or concentration of labelled cells in one thalamic subdivision and a sparser population of labelled cells in other thalamic subdivisions. The most striking example of a pattern is produced by injecting AI. This injection resulted in a band in the ventral division of the medial geniculate body densely populated with labelled cells; but even after the smallest injection, labelled cells were also found outside the ventral division, in the magnocellular and dorsal divisions of the medial geniculate body, and in the posterior group. (The ventral extremity of the ventral division was always free of cells and this sector is likely a separate nucleus which projects to Ep.) Other patterns are produced by injecting HRP in other cortical subdivisions: temporal injections produced a concentration in the caudal division of the medial geniculate body; insular injections resulted in a concentration in the medial sector of the posterior group; AII injections led to a concentration in the magnocellular and deep dorsal divisions of the medial geniculate body; injections in ventral Ep led to a concentration of labelled cells in the dorsal division of the medial geniculate body; finally, dorsal Ep seems to be very different from the other divisions inasmuch as injections in it resulted in labelled cells in non‐auditory thalamus–the pulvinar and lateral nuclei, as well as the auditory thalamus.These results lead to the following conclusions. The laminated and principal part of the ventral division of the medial geniculate body projects only to AI. Every other thalamic subdivision projects to two or more cortical subdivisions: the caudal division projects primarily to the temporal area with sparser projections to AII and Ep; the dorsal division projects primarily to Ep with sparser projections to AI, AII, and the temporal area; the medial sector of the posterior group projects primarily to the insular area and to the posterior ectosylvian gyrus; the magnocellular division of the medial geniculate body projects to every subdivision of auditory cortex, including AI and AII.