bluuebunny/crossref_metadata_2025_split huggingface dataset:
Response of the monkey cholinergic septohippocampal system to fornix transection: A histochemical and cytochemical analysis
Authors: Kordower Jeffrey H. , Fiandaca Massimo S. 
Published: January 2005

AbstractTransection of the fimbria‐fornix pathway is a paradigm that has been richly exploited in rats to assess the structural and functional correlates of cognitive behavior, neural grafting, and growth factor administration. Principally, the degeneration of cholinergic neurons within the septal/diagonal band region has received detailed attention following this manipulation. In contrast, no studies have examined the response of the cholinergic septal/diagonal neurons following axotomy in nonhuman primates. This study examined the neuronal and glial responses within the septal region to selective fornix transection (without cingulate gyrus ablation) in four Cebus apella monkeys. One month following unilateral transection of the fornix by means of an open microsurgical approach, a comprehensive loss of acetylcholinesterase [AChE]‐containing fibers was observed throughout the hippocampal formation and dentate gyrus ipsilateral to the lesion. Decreases in AChE fiber densities were also observed within the entorhinal cortex ipsilateral to the lesion. No such changes in AChE‐fiber density were consistently observed within the subicular region. The decrease in hippocampal AChE‐positive fibers was paralleled by a 49.5% reduction in cholinergic medial septal neurons as revealed by Nissl stains and immunohistochemical staining for the receptor for nerve growth factor, a marker of cholinergic basal forebrain neurons in primates. In contrast, no significant changes in the number of neurons within the vertical limb of the diagonal band were noted. Following the transection, a relatively intense reactive gliosis was observed within the dorsal half of the septal region ipsilateral to the transection and within the overlying transected corpus callosum. These data provide the foundation in nonhuman primates on which novel therapeutic factors can be evaluated in paradigms relevant to the study of Alzheimer's disease.
Topographic disorganization of the optic tracts following long‐term optic nerve regeneration: A quantitative image analysis study
Authors: Springer Alan D. , Morel Kimberly D. , Wilson Bryan R. 
Published: January 2005

AbstractExperiments were designed to find the degree to which regenerated optic axons occupied their previous locations in the optic tracts. Following optic nerve crush and regeneration, either the dorsal, Ventral, Peripheral, Temporal, or nasal part of the retina was ablated. The axons of the remaining retinal ganglion cells (RGCs) were labeled with cobalt. Density of the regenerated dorsal and ventral axons in the dorsal vs. ventral optic tracts was determined digitally. In addition, we determined the density of temporal and nasal axons in the temporal vs. nasal compartments of each optic tract and the density of central axons in the central vs. peripheral compartments of both optic tracts.Regenerated axons were not distributed randomly in the optic tracts. Instead, they were slightly but significantly biased toward growing through the tract or compartment that they had occupied previously. Still, the pathway specificity exhibited by the regenerated axons was closer to random than it was to the pathway specificity seen in normal animals. Dorsal, ventral, and central RGC axons were significantly better localized to their correct tract or compartment than were temporal or nasal RGC axons. Also, over time, dorsal and ventral axons tended to disappear from incorrectly chosen optic tracts. The slight bias toward choosing the appropriate optic tract or optic tract compartment may be enough to account for the topographic specificity of the regenerated retinotectal projection. Near‐randomness of the axonal positions in the tracts argues against the presence of any specific guidance cues in the optic tracts of adult animals. Axonal density was highest in the correct compartment and diminished progressively with increasing distance into the incorrect compartment. Such a gradient of axonal density suggests that regenerating axons “drift” away from their previous positions in the optic pathways.
Expression of surface glycoproteins early in leech neural development
Authors: McGlade‐McCulloh Ellen , Muller Kenneth J. , Zipser Birgit 
Published: January 2005

AbstractCell migration and axon growth during neural development rely upon cell‐cell and cell‐matrix interactions mediated by surface glycoproteins. The surface glycoprotein recognized on leech neurons by monoclonal antibody Lan3‐2 has previously been implicated in the process of axon fasciculation during regeneration in adults. In adult leeches, Lan3‐2 binds to a carbohydrate epitope of a 130 kD protein. The present study demonstrates that in embryos the antibody binds to the same carbohydrate epitope of glycoproteins with molecular weights of 130 kD and higher. As a first step in evaluating a possible role of the Lan3‐2 glycoprotein or the cells that express it during neural development, we determined its distribution in the developing nervous system of the leech Hirudo medicinalis. In embryos, Lan3‐2 epitope is expressed on fasciculated sensory afferents and it appears on the cell bodies before neurite outgrowth. The sensory fibers appear rostrally by embryonic day 10, less than halfway through development. Earlier, by 7 days of development at 20°C, Lan3‐2 binds to previously undocumented cell types: (1) cells appearing along the embryonic midline and (2) a cluster of cells located at the rostral edge of the germinal plate. These cells only transiently express this antigen and are present at critical left‐right and rostrocaudal boundaries during a period of cell proliferation, movement, and migration that produces the nervous system. Thus the Lan3‐2 surface glycoprotein or the cells expressing it are candidates for involvement in axon fasciculation, cell migration, and directed axonal growth.
Areal and laminar organization of corticocortical projections in the rat somatosensory cortex
Authors: Koralek Katherine‐Ann , Olavarria Jaime , Kellackey Herbert P. 
Published: January 2005

AbstractThe present study examines patterns of connectivity between the primary somatosensory cortex of the rat (SI) and surrounding cortical areas also implicated in the processing of somatosensory information. The impetus for the study was the recent reports of major differences in the organization of cortex lateral and caudal to the SI in two other rodent species; the mouse (Carvell and Simons, '86: Somatosens. Res. 3:213–237; '87: J. Comp. Neurol. 265:409–427) and the grey squirrel (Krubitzer et al., '86: J. Comp. Neurol 250: 403–430). Corticocortical connections between the somatosensory areas of the rat parietal cortex were examined by using the combined retrograde and anterograde transport of horseradish peroxidase as well as the retrograde transport of fluorescent tracers. Tracer injections were made into different locations within SI and dysgranular cortex as well as into more lateral regions of parietal cortex, The tangential patterns of distribution both of callosal connections and of cytochrome oxidase activity together provided points of reference in determining the relation between injection sites and the resultant patterns of label.The results indicate that two distinct somatosensory areas, SI and the dysgranular cortex, are interconnected with a further lateral somatosensory area referred to as the second somatosensory area (SII). These projections are organized in a topographic fashion, which we interpret as evidence for a single representation of the body surface in SII. The three somatosensory areas each exhibit unique laminar patterns of ipsilateral corticocortical projection neurons and terminations. In SI, projection neurons are found mainly in layers II, III, and Va, and terminations are largely restricted to the infragranular layers. In the dysgranular cortex, projection neurons and terminations are found in all layers except layer I in which only terminal label is detectable and layer Vb in which notably fewer neurons are labelled. In SII, projection neurons and terminations are found in all layers except layer I and are particularly dense in lower layer III and layer IV. Further, whereas the laminar and areal distributions of ipsilateral and contralateral corticocortical projections largely overlap in both SI and the dysgranular cortex, in SII they tend to be areally segregated. Neurons projecting bilaterally to both ipsilateral and contralateral somatosensory cortex were equally rare in all three somatosensory areas.These results are discussed in relation to the organization of SII in other rodent species, and it is concluded that in the rat, like the mouse, cortex lateral and caudal to SI contains a single representation of the body surface.
Postnatal development of crossed and uncrossed corticorubral projections in kitten: A PHA‐L study
Authors: Higashi Shuji , Yamazaki Masahiro , Murakami Fujio 
Published: January 2005

AbstractMorphological changes in individual corticorubral fibers and the pattern of crossed and uncrossed corticorubral projections were studied during the postnatal development of cats in order to understand cellular mechanisms for restriction of corticorubral projections with development. The anterograde tracer Phaseolus vulgaris leucoagglutinin (PHA‐L) was injected into restricted areas of the pericruciate cortex in kittens and PHA‐L‐labeled axons in the red nucleus were examined at postnatal days (PND) 7–73.In accordance with our previous study (Murakami and Higashi, Brain Res. 1988; 447:98–108), a crossed corticorubral projection was observed in addition to the uncrossed one in every experimental animal. During the early period of development (PND 7–8), swellings of irregular shape were observed along the entire course of the axons and they were often interconnected with extremely fine axonal segments. These axons bifurcated only infrequently and often ended as growth cones. These features were common to both uncrossed and crossed corticorubral axons. At later stages of development (PND 28 or later), the total number of swellings decreased and axonal swellings with smooth contours became dominant.A quantitative examination of axonal branches indicated that axons on the ipsilateral side branch occurred more frequently at later stages of development. However, there was no substantial change in branching frequency for the crossed corticorubral fibers during development. In parallel with morphological changes in individual axons, the crossed projection that was initially relatively abundant was reduced during development, Since a PHA‐L injection can be confined to a small region of cortex, topographic projections can easily be detected. At PND 7–8 there was no well‐defined topographic order in the ipsilateral corticorubral projection. Adult‐like topography was first discernible at PND 13.These observations suggest that the unilateral uncrossed corticorubral projection in the adult cat is achieved at least in part by the formation of axonal arbors in the uncrossed projection. This was accompanied by the failure of crossed fibers to form complex arbors. It is possible that a similar mechanism also operates in the formation of topographic maps.
DARPP‐32, a phosphoprotein enriched in dopaminoceptive neurons bearing dopamine D1 receptors: DIstribution in the cerebral cortex of the newborn and adult rhesus monkey
Authors: Berger Brigitte , Febvret Aude , Greengard Paul , Goldman‐Rakic Patricia S. 
Published: January 2005

AbstractDARPP‐32, a dopamine (DA) and cAMP‐regulated phosphoprotein, is associated with dopaminoceptive neurons bearing D‐1 receptors in the basal ganglia. The present study addressed the distribution of DARPP‐32 in the primate cerebral cortex and its putative association with D‐1 receptor laden cells in this structure. DARPP‐32‐like immunoreactive (LIR) neurons were examined in the cerebral cortex of 3‐day‐old (P3), 6‐week‐old (P42), and adult rhesus monkeys. In the younger cases, a large number of DARPP‐32 positive neurons, with the morphological characteristics of pyramidal cells, were observed throughout the cortex, in layers V–VI, and to a lesser extent in layer II and uppermost layer III. In the parietal, insular, temporal, and occipital cortices, DARPP‐32 positive neurons were arranged in a monolayer in layer Va. They were often clustered in small groups with a bundling of their dendrites. In the primary motor cortex, Betz cells were among the labeled population. In the association and somatosensory areas, the basal dendrites of DARPP‐32 positive neurons and the prominent tufting of their apical dendrites in layer I contributed to an essential bilaminar pattern resembling the distribution reported for DA afferents and D‐1 receptors in these areas. The prominence and widespread distribution of DARPP‐32 positive neurons in layer V may be a specialization of primate cortex since such cells are found only in restricted locations in rodents. The literature on the connections of the cerebral cortex suggests that a large number of the DARPP‐32 positive neurons in layer VI and perhaps even in layer Va may be corticothalamic neurons. An important developmental observation was the presence of DARPP‐32‐LIR neurons in the white matter. They were prominent in the neonates but could not be seen in the adult. Their location as well as their type and shape were reminiscent of interstitial neurons. In the adult monkeys, the distribution of DARPP‐32‐LIR neurons was more circumscribed: they were numerous in the ventral temporal gyrus and in areas related to the limbic system: caudal orbitofrontal cortex, insula, temporal pole, entorhinal, and anterior cingulate cortex. Weak labeling was detected in layer Va of the superior temporal and parietal cortex, in some prefrontal areas (10,13, and medial 9), and in the premotor and supplementary motor cortex; in adults, unlike neonates, few DARPP‐32‐LIR neurons were present in the dorsolateral prefrontal cortex, the primary motor or the primary visual or prestriate cortices. These findings demonstrate important developmental changes between birth and adulthood in the expression of DARPP‐32 and point to a possible role for this molecule and/or D‐1 receptors during postnatal development of the primate cerebral cortex.
Projections to the pontine nuclei from choline acetyltransferase‐like immunoreactive neurons in the brainstem of the cat
Authors: Aas Jan‐Erik , Brodal Per , Baughman Robert W. , Storm‐Mathisen Jon 
Published: January 2005

AbstractBy use of retrograde transport of horseradish peroxidase‐wheat germ agglutinin (HRP‐WGA) in combination with monoclonal antibodies against choline acetyltransferase (ChAT), we show that putative cholinergic inputs to the feline pontine nuclei originate from cells in the dorsolateral pontine tegmentum. These cells form a loosely arranged continuum that nevertheless may be subdivided into two groups on the basis of differences in cell morphology. One group consists of double‐labeled cells in the periventricular gray substance medial to, and partly merging with, the nucleus locus coeruleus. The other group consists of double‐labeled cells surrounding the brachium conjunctivum. In two cats with tracer injections in the pontine nuclei, 81% and 84%, respectively, of the retrogradely labeled cells in the dorsolateral pontine tegmentum are ChAT‐like immunoreactive (ChAT‐LI). In the same experiments, many ChAT‐LI cells, but no retrogradely labeled cells, are seen in the basal telencephalon.The pontine nuclei contain a plexus of thin ChAT‐LI fibers with varicosities resembling en passant as well as terminal boutons. These ChAT‐LI fibers appear to branch extensively and cover all parts of the pontine nuclei.Following injections of rhodamine‐B‐isothiocyanate (RITC) in the thalamus and Fluoro‐Gold in the pontine nuclei and surrounding regions in the same animal, all retrogradely labeled cells in the dorsolateral pontine tegmentum are labeled with both tracers, whereas most cells in the paramedian pontine reticular formation are labeled either with RITC or Fluoro‐Gold. Thus it appears that all cells in the dorsolateral pontine tegmentum that project to the pontine nuclei also project to the thalamus.In analogy with findings by others in the dorsal lateral geniculate nucleus, we suggest that the putative cholinergic projections to the pontine nuclei may serve to modulate transmission of cerebellar afferent information in accordance with the behavioural state of the animal.
Development of connections to and from the visual cortex in the wallaby (Macropus eugenii)
Authors: Sheng X.‐M. , Marotte L. R. , Mark R. F. 
Published: January 2005

AbstractThe time course of the development of connections between the visual cortex and the main subcortical visual structures, as well as intrahemispheric and interhemispheric connections, has been studied in the marsupial wallaby (Macropus eugenii) to compare its development with that of placental mammals. Pouch young are born prior to retinal innervation of the primary visual centers and spend a protracted period of development in the pouch, making them ideal for visual, developmental studies. Horseradish peroxidase conjugated to wheatgerm agglutinin was injected into either the presumptive visual cortex or the superior colliculus in young of varying ages.Thalamocortical projections from the dorsal lateral geniculate and lateral posterior nuclei reach the presumptive visual cortex between 12 and 15 days after birth. Descending cortical connections form later. Corticogeniculate axons are first detected in the geniculate and lateral posterior nucleus at 48 days after birth, while corticocollicular axons first reach the superior colliculus at 71 days and, by 81 days, have innervated the superficial layers.Intrahemispheric and interhemispheric connections form even later. By 99 days intrahemispheric axons from area 17 have accumulated in visual association areas but are yet to invade layers III and IV, their major termination zones in adult, while axons projecting back to area 17 have also reached their target area. At this time interhemispheric axons from area 17 have begun to accumulate in the opposite visual cortex, although they have not invaded the cortical layers. By 111 days cortical cells projecting to the opposite visual cortex are first labelled. These have a more widespread distribution in area 17 at 111 and 122 days compared to the adult, where they are confined to the 17/18 border.The results show that the marsupial wallaby has a timetable of similar sequence, but different relative timing, in. the formation of cortical connections compared to that of placental mammals. In the first half of the period between conception and eye opening, the timing in the wallaby precedes considerably that in placental mammals. Ascending connections from the thalamus develop relatively earlier in the wallaby but descending collicular connections are delayed until the same relative time that they appear in placental mammals.
Expression of the prodynorphin gene in the developing and adult cerebral cortex of the rat: An in situ hybridization study
Authors: Alvarez‐Bolado Gonzalo , Fairén Alfonso , Douglass James , Naranjo José Ramón 
Published: January 2005

AbstractA population of cortical neurons contains the opioid peptide dynorphin; the laminar distribution of these neurons in the adult cerebral cortex and their patterns of development are not well known. We have utilized in situ hybridization techniques to localize prodynorphin mRNA‐containing neurons. Rats aged from embryonic day (E) 15 through postnatal day (P) 90 were used. Prenatal animals did not show any labeling in the cerebral cortex. By P4, prodynorphin was expressed in a small number of cortical neurons for the first time. The autoradiographic signal was restricted to perikarya. In the frontoparietal cortex, labeled neurons first appeared in layer V and the upper part of layer VI. Subsequently, from P11 onward, the band expanded in an “inside‐out” sequence to include layers IV through II. In the posterior cingulate cortex and in the insular and perirhinal cortices, prodinorphin mRNA containing‐neurons were located preferentially in layer V. In all cortical areas analyzed, a progressive increase in the packing density of neurons expressing prodynorphin mRNA was observed until P14; it decreased slightly thereafter.
Collateral sprouting of the central terminals of cutaneous primary afferent neurons in the rat spinal cord: Pattern, morphology, and influence of targets
Authors: Fitzgerald Maria , Woolf Clifford J. , Shortland Peter 
Published: January 2005

AbstractThe capacity of the central terminals of primary afferents to sprout into denervated areas of neonatal spinal cord and the morphology of any novel terminals has been investigated. In rats which had undergone sciatic nerve section on the day of birth, 12 of 18 physiologically characterized intact saphenous hair follicle afferents (HFAs) were labelled intra‐axonally with horseradish peroxidase (HRP) were shown to sprout up to 2,000 m̈m into the deafferented sciatic terminal field. The morphology of these sprouts depended on which area of the sciatic nerve territory was invaded by the afferent sprouts. Six HFAs sprouted into areas normally innervated by glabrous skin afferents and the morphology of the collateral sprouts in this region resembled that of rapidly adapting (RA) afferents. The other six saphenous HFAs had sprouted into sciatic “hairy” skin areas and the morphology of these sprouts, although abnormal, was flame shaped.In rats whose sural, saphenous, and superficial peroneal nerves were cut at birth, 4 of 7 single HRP labelled RA afferents had central terminals that had sprouted into regions of cord normally devoted to “hairy” input. These showed clear signs of HFA morphology despite their peripheral receptive fields remaining in the glabrous skin.The results show collateral sprouting of single cutaneous sensory afferent axons into adjacent inappropriate central target regions following neonatal deafferentation. Such plasticity may provide some compensation following neonatal injury. The morphology of the sprouted terminals is appropriate to the new target area rather than to its functional class and is also independent of the peripheral receptive field location providing an example of central rather than peripheral control over afferent growth patterns.