bluuebunny/crossref_metadata_2025_split huggingface dataset:
Projection of the lateral part of the entorhinal area to the hippocampus and fascia dentata
Authors: Hjorth‐Simonsen A. 
Published: December 2004

AbstractThe hippocampus and fascia dentata receive their major extrinsic input from the entorhinal area through the so‐called perforant path. This pathway is now shown to be composed of at least two distinct fiber systems: (1) A medial perforant path coming from the medial part of the entorhinal area and terminating in the middle of the dentate molecular layer and in the deep half of the stratum lacunosum‐moleculare of the hippocampal subfield CA3. (2) A lateral perforant path from the lateral part of the entorhinal area to a superficial zone in the dentate molecular layer and to the superfcial part of the stratum lacunosum‐moleculare of CA3. This paper deals specifically with the lateral perforant path. A third group of perforant fibers, bing intermediate to the others with regard to both origin and termination has been noticed in one animal.The fiber‐course of the lateral perforant path is found to be identical to that previously described for the medial path. The terminal field is present along the whole axial extent of the hippocampus and fascia dentata, i.e., from the temporal tip to the subsplenial portion.No sings of degeneration corresponding to the so‐called alvear path were observed following lesions of either the medial or the lateral part of the entorhinal cortex.Terminal degeneration appeared in the molecular layer of the subiculum and CA1 and in the anterior continuation of the hippocampal formation subsequent to lesions including the prepyriform cortex.
Experiments to determine whether retinogeniculate axons can form translaminar collateral sprouts in the dorsal lateral geniculate nucleus of the cat
Authors: Guillery R. W. 
Published: December 2004

AbstractAn earlier study has shown that in young kittens, but not in adult cats, section of one optic nerve produces a curious pattern of cell survival in the denervated geniculate laminae. Most of the cells in these laminae are shrunken, but a few large cells remain close to the borders of the adjacent, normally innervated laminae, giving the impression that these cells are sustained by collaterals arising from the normal retinogeniculate axons.Adult cats and kittens aged 7, 9 and 20 days have been used to determine the extent to which normal retinogeniculate axons can invade a denervated geniculate lamina. One eye was removed and the animals were kept for periods varying from four months to four years. The fiber degeneration produced by removal of the second eye was then studied. There is no evidence for any collateral sprouting in the adults. If the first operation is done at seven or nine days a limited number of axons grow across laminar borders and invade a small border zone of the denervated laminae. These axons do not appear in all of the regions that show surviving large border cells.It is concluded that new sprouts are probably not formed, but that growing axons can invade an inappropriate lamina if this is denervated during the normal period of axonal growth.
Experimental‐anatomical studies on the “middle temporal visual area (MT)” in primates. I. Efferent cortico‐cortical connections in the marmoset Callithrix jacchus
Authors: Spatz W. B. , Tigges J. 
Published: December 2004

AbstractThe efferent cortico‐cortical fiber connections of the middle temporal visual area (MT) have been studied. The primate area MT was shown by various authors to receive a fiber projection from area 17; physiologically it shows a retinotopical organization. Lesions placed in area MT of Callithrix revealed a surprising variety of cortico‐cortical connections. Termination sites of degenerating axons were found ipsilaterally in the frontal eye field and in eight regions of the temporal, parietal and occipital lobes all known to be photically responsive.Callosal fibers terminated in the contralateral area MT and in two adjoining areas. The termination site in area MT suggested a homotopic point to point connection meaning that in area MT the entire retinal representation is connected transcallosally, whereas in the classical visual areas only the regions of midline representation are connected.The projection of intrinsic interlaminar fibers from the supragranular layers upon layer V was weakly developed in area MT.
Observations on complex vesicles, neurofilamentous hyperplasia and increased electron density during terminal degeneration in the inferior colliculus
Authors: Jones E. G. , Rockel A. J. 
Published: December 2004

AbstractThe central nucleus of the inferior colliculus has been examined electron microscopically two, four and five days after section of the lateral lemniscus and four and five days after ablation of the auditory cortex. The findings confirm the differential distribution of lateral lemniscal and corticofugal fibers to the two divisions of the central nucleus and, in the case of the lateral lemniscal fibers, to the two cell types of the ventro‐lateral division.The material from brains in which the lateral lemniscus was divided contains examples of every type of terminal degeneration which has been described: swelling and glycogen deposition, swelling (often with flattening) of synaptic vesicles, neurofilamentous hyperplasia, greatly increased electron density. At two days, only the first three of these are seen; at four days, all occur together; at five days, only the electron dense type is present. In addition, at two days, a proportion of the early degenerating terminals show almost complete loss of synaptic vesicles and their replacement by the empty “shells” of complex vesicles (of Gray). Aggregations of shell fragments can be discerned at this and later survival periods clustered about presynaptic membranes left devoid of synaptic vesicles.These observations are considered in terms of recent concepts of the mode of formation and release of synaptic vesicles. It is postulated that terminals showing replacement of synaptic vesicles by shell fragments may have been excessively stimulated during or after the operation and have, thus, had a higher turn‐over of synaptic vesicles. It is suggested that, in this and other sites, accumulation of large numbers of shell fragments may be a necessary pre‐requisite for neurofilamentous hyperplasia, the protein of the shells being reorganized into neurofilaments.
Spreading of uncrossed retinal projection in superior colliculus of neonatally enucleated rabbits
Authors: Chow Kao Liang , Mathers Lawrence H. , Spear Peter D. 
Published: December 2004

AbstractDutch‐belted rabbits were enucleated shortly after birth and allowed to survive 14–26 weeks. In some animals, the second eye was then removed and the distribution of retinal axons studied. It was found that while there was no evidence of axonal sprouting in the lateral geniculate body, uncrossed retinofugal axons had spread throughout the lateral half of the superior colliculus, in areas normally innervated only by the contralateral eye.Other animals were prepared for electrophysiological recording, to see if neurons in the area of new axonal growth could be activated by light or electric shock to the optic nerve. Only four of 70 neurons tested could be driven by light, and only two of 26 tested could be driven by shock. All responsive neurons were judged to be located within the limits of the normal ipsilateral projection. It is concluded that while anatomical evidence of spreading of the uncrossed retinal input has been shown, the functional significance of this new growth is yet to be demonstrated.
Transneuronal cell atrophy in the congenitally deaf white cat
Authors: West Christopher D. , Harrison J. M. 
Published: December 2004

AbstractDeaf white cats with congenitally determined lesions of the organ of Corti were found to have transneuronal degeneration in the form of reduced cell size in the ventral cochlear nucleus and the superior olivary complex. A young deaf white cat with a normal spiral ganglion cell population showed no evidence of acoustic nerve fiber or ending loss despite the presence of atrophied cells in the ventrical cochlear nucleus. Spiral ganglion cell depopulation as found in an adult deaf white cat was evident only in the lower cochlear turns. Graphic reconstructions of the cochleas showed that deaf white cats fell within the normal range of cochlear length and spiral development. A non‐deaf white cat with overdeveloped convolutions of the lateral superior olivary nucleus had the most extensively coiled cochlea of the cats examined.
A comparison of visual pathways in Boston and Midwestern Siamese cats
Authors: Shatz Carla 
Published: December 2004

AbstractA genetic mutation in Siamese cats causes retinogeniculate fibers representing roughly the first 20 degrees of ipsilateral visual field in each eye to cross aberrantly in the optic chiasm and terminate in the wrong lateral geniculate nucleus (LGN). Previous investigations have shown that in the visual cortex this extra representation of ipsilateral visual field can be organized into one pattern in Boston Siamese cats, another in Midwestern. This finding was confirmed here.The possibility that the organization of the LGN might account for these two patterns was studied using combined anatomical and physiological methods. On the basis of microelectrode recordings from the visual cortex, 11 out of the 12 Siamese cats included here were Boston cats; one was Midwestern. The distribution of retinogeniculate terminals was examined in each cat using autoradiographic techniques following an eye‐injection of 3H‐proline. Overall, the LGN organization in Boston cats was similar to that of Midwestern: both lateral and medial normal segments of lamina A1 (mnA1) were present. In Boston cats, however, the mnA1 was remarkably small and shifted ventromedially in the nucleus to allow for the fusion between the medial borders of lamina A and the abnormal segment of A1. In the Midwestern cat this fusion was not apparent and the medial normal segment of A1 was significantly larger.These differences in organization of the LGN are consistent with those seen at the level of the visual cortex in Midwestern and Boston Siamese cats. It was not possible, however, to relate them clearly to the characteristic strabismus of these animals.
Cortical projections of posterior parietal cortex in owl monkeys
Authors: Kaas J. H. , Lin C. S. , Wagor E. 
Published: December 2004

AbstractEfferent cortical projections of posterior parietal cortex were determined by degeneration and autoradiographic methods in owl monkeys. Intraregional connections were to the immediate surround of the injection or lesion site, and to distinct foci within the posterior parietal region. The extraregional ipsilateral connections were with (1) previously established subdivisions of visual association cortex (the Dorsomedial Area, the Medial Area, the Dorsolateral Area, and the Middle Temporal Area), (2) other locations in caudal neocortex, and (3) frontal cortex. The callosal projections were to separate foci in posterior parietal cortex of the contralateral cerebral hemisphere. The separate foci of both ipsilateral and contralateral terminations in posterior parietal cortex raise the possibility that this region contains more than one functional subdivision. The connections with visual association cortex suggest a role for parietal cortex in visual behavior. Other foci in caudal neocortex indicate the possible locations of additional subdivisions of association cortex.
Development of the barrels and barrel field in the somatosensory cortex of the mouse
Authors: Rice Frank Lambert , Van Der Loos Hendrik 
Published: December 2004

AbstractBarrels of the PMBSF of the mouse somatosensory cortex become apparent in Nissl‐stained tangential sections simultaneously, on the fourth postnatal day. At this time they are miniatures of those in the adult and are situated in the deepest sublamina of the trilaminar cortical plate. An early barrel appears as a patch of decreased cell density: the prospective hollow of the barrel. Septa become noticeable during the sixth postnatal day. From that period to adulthood, the relative contribution of the PMBSF to the total cortical surface area increases — an increase that goes against one's expectation: the barrel related periphery matures very early and so does the central, lateral region of the cortex. Barrel growth parallel to the pial surface is greater along the major axes than along the minor axes. By using the barrels to identify prospective layer IV in immature cortex, we could determine that layers V and VI attain their adult height during the sixth postnatal day — an age when prospective layers I‐IV are only half their adult height. The onset of barrel formation coincides with the moment after which injury to the pertinent somatosensory periphery (the vibrissal papillae) no longer causes profound alterations in barrel morphology.
Brain stem afferents to the festigial nucleus in the cat demonstrated by transport of horseradish peroxidase
Authors: Ruggiero David , Batton Robert R. , Jayaraman A. , Carpenter Malcolm B. 
Published: December 2004

AbstractAlthough retrograde and anterograde degeneration studies have provided important information concerning brain stem afferents to the fastigial nuclues (FN), these data may be incomplete and should be confirmed by axonal transport methods. Attempts were made to inject horseradish peroxidase (HRP) unilaterally into the FN in a series of adult cats. Animals were perfused with dextran and a fixative solution of paraformaldehyde and glutaraldehyde in 0.1 M phospate buffer. Representataive sections were treated by the Graham and Karnovsky (1966) method.Selective HRp injections in one FN resulted in retrograde transport of the marker of Purkinje cells of the ipsilateral vermis and distinctive appendages of the contralateral medial accessory olivary (MAO) nucleus (nucleus β and the dorso‐medial cell column). Retrograde transport of the label was found bilaterally in cells of the medial (MVN) and inferior (IVN) vestibular nuclei, in cell group x and in the nucleus prepositus (PP). Labeled vestibular neurons, most numerous in MVN, were identified in dorsal, caudal and lateral regions, with a slight ipsilateral preponderance. Only a few neurons in caudal, dorsal and lateral regions of th IVN were labeled and none of these included cells of group f. Labeled cells in the caudal third of PP were greatest ipsilaterally. Rostral and caudal injections of FN labeled smaller numbers of cells in MVN, IVN, cell group x and PP.HRP injections of FN and portions of lobules VIII and IX resulted in bilateral retrograde lableing of larger numbers of cells in MVN, IVN and cell group x, and ipsilateral labeling of cells in group y and the interstitial nucleus of the vestibular nerve. Injections of HRP into basal folia of lobules V and VI resulted in retrograde transport of the marker to cells of the medial and dorsal accessory olivary nuclei contralaterally, and to cells of the ipsilateral accessory cuneate nucleus. Transport of label injected into portions of the pyramis was detected in parts of the contralateral MAO and bilaterally in parts of the pontine and reticulotegmental nucleiThis study suggests that the principal afferents of the fastigial nucleus arise from: (1) Purkinje cells of the ipsilateral vermis, (2) restricted portions of the contralateral MAO (nucleus ß and dorsomedial cell column), (3) portions of the MVN and IVN (bilaterally) and (4) caudala parts of the PP. Secondary vestibular inputs to the fastigial nucleus probably are relayed mainly by cells in the cerebellar cortex.
Hair cell distribution and orientation in goldfish otolith organs
Authors: Platt Christopher 
Published: December 2004

AbstractStructurally diverse sensory regions occur in the otolith organs of the goldfish inner ear. Scanning electron microscopy reveals regional distinctions based on thre criteria. (1) Hair cells have difference sizes of apical bundles, based on thickness. In all three maculae, two central regions have hair cells with bundles significantly thicker than those in surrounding regions. (2) Hair cell population density varies, with regional aggregations present. The central regions with thick bundles have two to three times the density of surrounding regions with thin bundles, and contain 40‐80% of the total hair cell number in each macula. (3) Hair cell orientation maps show that each macula has two oppositely oriented cell populations that can be separated completely, not by a zone of interspersion, but apparently by a single unbroken lineThe lagena is like the utricle in having hair cells with the kinocilium on the side of the cell toward the opposition line, but in the saccule the kinocilia face away from the line, and the small macula neglecta consists of two completely separate, oppositely oriented patches. The opposition line does not divide each macula simply down its midline; instead, the line divides the regions with thick bundles into narly equal opposing aras, except for a remarkably abrupt large loop in the line in the anterior part of the sacculeThe regional structural diversity in these organs may relate to localized functional diversity of responses to tilt, vibration and sound.
Scanning electron microscopy of the subarachnoid space in the dog. V. Macrophages challenged by bacillus calmette‐GUERIN
Authors: Merchant Randall E. , Low Frank N. 
Published: December 2004

AbstractMongrel dogs were anesthetized intraperitoneally with pentobar‐bitol. One cc of cerebrospinal fluid was drawn through a needle inserted into the cisterna magna and mixed with 1 cc (4–9 million viable BCG organisms) of freeze‐dried bacillus Calmette‐Guerin. One minute later this mixture was injected by the same needle into the cisterna magna. At 1 and 12 days postinjection, experimental animals were perfused with buffered aldehydes. Samples of the leptomeninges were post‐fixed in OsO4 and routinely prepared for scanning and transmission electron microscopy. Leptomeningeal samples of untreated, control animals were similarly prepared.Scanning and transmission microscopy confirm that free cells resting on the sub‐arachnoid linings and within the subpial connective tissue space of control animals possess the morphology of macrophages (Malloy and Low, 1976). Viable BCG in the subarachnoid space produces a 3‐fold increase in the free cell population of the leptomeninges in 24 hours and a 10‐fold increase in 12 days. These cells tend to form associations varying from loose aggregates to tight clusters. Approximately 80% of these free cells express macrophage morphology, with abundant plasma‐lemmal microappendages and cytoplasmic vacuoles. Transmission electron microscopy of the free cell population of BCG‐stimulated animals reveals at least two other members of the leukocyte series on the leptomeningeal linings.
Afferents to the optic tectum of the leopard frog: An HRP study
Authors: Wilczynski Walt , Northcutt R. Glenn 
Published: December 2004

AbstractFolowing unilateral HRP injections in the optic tectum of Ran pipiens, HRP ‐ positive cells were seen in three pretectal nuclei: bilaterally in the dorsal posterior nucleus; in the dorsal half of the ipsilateral posterior nucleus; and ipsilaterally in the large‐celled pretectal nucleus. HRP ‐positive cells were also seen ipsilaterally in the anterodorsal, posterodorsal and posteroventral tegmental fields, the nucleus isthmi, and the dorsal gray columns of the cervical spinal cord; bilaterally in the suprapeduncular nucleus, a paramedian cell group dorsal to the interpeduncular nucleus; and in the deep layers of the contralateral tectum. In addition, evidence for a bilateral ventral preopto‐tectal projection was seen in half the experimental animals. No tectal afferents from telencephalic or rostral thalamic areas were seen. Both the ascending and descending tectal efferent fibers were also filled with reaction product. The pale reaction indicative of terminating tectal efferents was seen in the dorsal pretectum, partially overlapping the lateral nucleus and uncinate neuropil; in the core of nucleus isthmi; and in the superior olive.
Rearrangements of the retinotectal projection in Rana pipiens after unilateral caudal half‐tectum ablation
Authors: Udin Susan H. 
Published: December 2004

AbstractWhen the caudal half‐tectum is ablated aid the optic nerve is cut in adult Rana pipiens, recordings from optic nerve terminals show that the entire visual field comes to be represented in retinotopic ordcr on the reinairring rostral half‐tecturn (compression). In contrast, if the caudal half‐tectum is ablated but the optic nerve is left intact, no compression of the retinotectal projection results. Instead, the terminals displaced from the ablatcd tissue form apermanently disorganized projection to the rostral half‐tectum superimposed on the unaltered representation of those parts of the retinawhich normally project there. The receptive field locations of tectal ncurons in both groups of animals show that the altered retinotectal projections make functional synapses. This conclusion is further supported by hehavioral data. which show that the accuracy of prey‐catching movements is altered in both groups of frogs.The anomalous retinotectal maps can be interpreted by menas of amodel which includes polarity cues derived from the tectum and ordering cues derived from repelling interactions among fiber terminals.