Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:1.11.1.7 (peroxidase)
 65,474 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

1. Electrophysiological and morphological (retrograde axonal transport of horseradish peroxidase, HRP) experiments have been carried out in the cat in order to study the associative projections from area SI to ipsilateral SII. 2. Microelectrode recordings were performed in the forepaw focus of SII both in normal (64 units) and in SI-undercut (51 units) cats. 29.6% of the neurons recorded in the unoperated and 29.4% of those collected in the operated cats were excited by electric stimulation of the ipsilateral SI (forepaw focus). In both preparations almost all such units were endowed with large (either contra- or bilateral) receptive fields (RF). Cell population recorded in the SI-undercut cats showed no significant impairment to peripheral stimuli and/or changes in the size of the RFs. 3. From the forepaw focus of SI, 150 units have been recorded and tested by stimulation of the homologous focus of the ipsilateral SII. Eight of them were fired antidromically and thus identified as association cells. Their RFs were very small and located only in the digits of the contralateral forepaw. 4. Both single or multiple HRP injections were performed in SII. Retrogradely labelled cells were found in the ipsilateral SI. The great majority of association cells are pyramids and dwell mainly in layer III. In spite of the large diffusion of the exogenous reaction product in the injected SII and of the presence of retrogradely labelled cells anywhere in the ipsilateral thalamic VB complex, the distribution of association cells is unequal throughout SI since they strongly predominate in the digit zone of the forepaw representation.
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PMID:Anatomical and functional aspects of the associative projections from somatic area SI to SII. 8 62

Horseradish peroxidase (HRP) was injected into the first (SI) or second (SII) somatosensory areas of 21 adult cats. The radial and tangential (normal and parallel to the pial surface, respectively) distribution and morphology of the callosal neurons were studied. HRP injections were combined with single unit recording in the contralateral cortex in order to determine which part of the somatosensory periphery is represented within the regions containing callosal neurons, the callosal (efferent) zones, in SI and SII. The callosal zone of SI extends over the trunk and part of the forepaw representation. In the forepaw and hindlimb representations callosal neurons projecting only to the contralateral SII are found, while in the trunk representation callosal neurons projecting to contralateral SI or SII are found. The callosal zone in SII extends widely throughout the forepaw representation in this area and projects to the contralateral SII but not to SI. In both SI and SII the callosal neurons are mainly located in layer III. A few of them are also found in layer VI. They are very rare in other layers. Callosal neurons in layer III are mostly pyramidal but exceptionally stellate; in layer VI they are pyramidal, triangular, and occasionally stellate. These data indicate that transformations of the cortical somatosensory maps are achieved in the message sent through the corpus callosum. These transformations are i) determined by the extent and location of the callosal zones and perhaps by the distribution of callosal neurons within them, ii) different in different areas, iii) different in a same area, according to the cortical targets to which they are conveyed. The existence of callosal connections originated from areas of distal forepaw representation supplies a possible anatomical substrate for those types of intermanual transfer of tactile learning which depend upon the integrity of the corpus callosum.
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PMID:The anatomical substrate of callosal messages from SI and SII in the cat. 8 55

Descending connections from parietal cortex to pulvinar in squirrel monkey were investigated with the autoradiographic method. Somatosensory areas I (SI) and II (SII) were found to project to the oral (PuO) and medial (PuM) subdivisions of the pulvinar. Projections from the posterior parietal region were recorded in circumscribed areas of PuM and the lateral (PuL) and inferior (PuI) subdivisions of pulvinar. Retrograde labeling with horseradish peroxidase (HRP) demonstrated that rostral parietal cortex including the lateral cortex of SI and the rostral part of area 5 received reciprocal projections from PuO and rostral PuM. Injections of HRP into medial and lateral regions of SI also resulted in labeled cells in PuO and PuM. Within the limitations of the HRP technique, the latter results suggest a direct pathway from pulvinar to primary sensory cortex. The experimental results confirm the accepted view of projections from parieto-temporo-occipital "association" cortex to PuM, PuL and PuI. In addition, reciprocal connections of rostral parietal cortex with PuO and PuM were demonstrated.
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PMID:A horseradish peroxidase-autoradiographic study of parietopulvinar connections in Saimiri sciureus. 9 28

Corticals cells projecting to the dorsal column nuclei (DCN) of Rhesus monkeys have been identified after unilateral or bilateral injection of horseradish peroxidase (HRP) into the dorsal medulla. HRP-positive neurons identifiable as the source of cortico-DCN projections were pyramidal cells in layer V whose largest diameters ranged from 12--31 micron. Cortico-DCN neurons were concentrated in the trunk, fore- and hindlimb regions of area 4 and of SI, and to a lesser extent in SII. This distribution is comparable to the topographical distribution of cortico-DCN neurons in cats. However, cortico-DCN neurons in monkeys are also numerous in at least part of the supplementary motor cortex and in area 5. The results suggest that cortical neurons in several different cytoarchitectonic areas may exert direct control upon cells in the DCN and that the functional role of cortic-DCN projections ought not be view as a simple "feedback" system.
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PMID:Cortical cells projecting to the dorsal column nuclei of rhesus monkeys. 40 62

Afferent connections to the ventrobasal complex (VB) of the thalamus were studied by means of retrograde transport of horseradish peroxidase (HRP) and by the Golgi-method. After HRP-injection into the VB, peroxidase-positive cells were observed contralaterally in the dorsal column nuclei (DCN), in the trigeminal nuclei and in the lateral cervical nucleus (LCN), and ipsilaterally in the somatosensoty I (SI) and II (SII) cortical areas. Labeled cells of different shape and size were compared with neurons impregnated by the Golgi-technique. On tn size and shape even within one region and that they correspond to the relay or efferent neurons observed in the Golgi-material.
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PMID:A combined horseradish peroxidase and Golgi study on the afferent connections of the ventrobasal complex of the thalamus in the cat. 47 13

By means of the method based on the retrograde axonal transport of exogenic horse-radish peroxidase, there have been stated the sources of afferent pathways of the motor cortex and the structure of neurons sending their axons to the given region. The marked neurons have been found in ipsilateral (SI, SII, Pr, Limb.) and contralateral cortex (MI, Limb.), as well as in the diencephalon (LP, VPL, Hp), the mesencephalon (NR, SN, TM) and the pons (TP). The complex investigation (the peroxidase method and electron microscopy) allowed to get an idea on morphological substrate of disynaptic pathways.
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PMID:[Sources of the afferent pathways of the motor cortex in cats revealed by using the peroxidase method]. 66 78

Retrograde transport of horseradish peroxidase (HRP) was used to determine the extent and some of the organizational details of the cortical projection of the ventroposterior thalamic complex (VP) in the marsupial brush-tailed possum, Trichosurus vulpecula. The cortical projection field of VP is coincident with SI as determined by electrophysiological methods, and would appear not to overlap fully the primary motor cortex. Thus, in Trichosurus it appears that the motor and somatic sensory cortical regions are not fully congruent, unlike those of the American opossum, Didelphis, which are. Each division of VP projects discretely, in a non-overlapping manner, to various regions within SI. The ventrolateral subdivision or VPL projects medially and in a strict homotypic manner, though the proportion of VPL cells projecting to cortex is subject to a large amount of variation. The dorsomedial division of VP or VPM projects uniformly to cortex from all areas of that subnucleus, but the strict homotypy characteristic of VPL's projection was not as apparent. VPM also projects to two distinct regions within its cortical field. The posteromedial division of VP or VPP projects to an area of cortex that receives no other VP input but, on the basis of cortical mapping studies, appears to belong to SI. Projections from VPL (and presumably from VPM) to a small area of cortex in the extreme posterolateral part of the VP field correspond to the position expected for, and electrophysiologically confirmed to be, SII.
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PMID:The organization of neocortical projections from the ventroposterior thalamic complex in the marsupial brush-tailed possum, Trichosurus vulpecula: a horseradish peroxidase study. 68 87

Single injections of tritiated amino acids into the first somatic sensory area (SI) of the rat neocortex result in axoplasmically transported labeling of the stratum griseum intermidiale and stratum griseum profundum of the ipsilateral superior colliculus. The terminal labeling in these layers takes the form of multiple, column-like patches. The SI projection is somatotopically organized with the face and head representations projecting to an extensive anterolateral part of the colliculus and the limb representations projecting to a restricted posterolateral part. Injections of horseradish peroxidase into the superior colliculus result in retrograde labelling of corticotectal cells in the superficial part of layer VB of SI and of the second somatic sensory area (SII).
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PMID:Somatotopic and columnar organization in the corticotectal projection of the rat somatic sensory cortex. 90 93

The cortical connections of two vestibular fields [parieto-insular vestibular cortex (PIVC) and area 3aV] were studied in the squirrel monkey (Saimiri sciureus) by means of retrograde tracer techniques. Small iontophoretic or pressure injections of horseradish peroxidase (HRP), wheat-germ-HRP, Nuclear Yellow, and Fast Blue were administered to the cytoarchitectonic areas Ri (PIVC), 3aV, the parieto-temporal association area T3, the granular insula (Ig), and the rostral part of area 7 (7ant). The injection sites were physiologically characterized by means of microelectrode recordings and vestibular, optokinetic, or somatosensory stimulation: Area Ri is the region of the parieto-insular vestibular cortex (PIVC) as defined in macaques. The neck-trunk region of area 3a (area 3aV) also contains many neurons responding to stimulation of semicircular canal receptors. Some neurons of area T3 bordering on the PIVC also receive vestibular signals, but most neurons in area T3 responded preferentially to large-field optokinetic stimulation and not to vestibular stimulation. In none of the areas mentioned were responses to otolith stimulation found. The PIVC receives inputs from frontal and parietal cortical areas, especially areas 8a, 6, 3a, 3aV, 2, and 7ant. Area T3 receives signals from the insular and retroinsular cortex, various parts of area 7, visual areas of the parieto-occipital and parieto-temporal regions (area 19) and from a sector of the upper bank of the temporal sulcus (STS-area). The cortical afferents to area 3aV stem from areas 24, 4, 6, 7ant, from other parts of the primary somatosensory cortex, the secondary somatosensory cortex (SII), the retroinsular cortex (Ri), and the granular insula (Ig). In the border region of the areas 2 and 7ant, labelled neurons appeared after injections into both the PIVC and the area 3aV. This region is presumably the homologue to the vestibular area 2v of the macaque brain. In all regions cells within the contralateral cortex were less frequently labelled than cells in the homologous structures of the ipsilateral hemisphere. The cortical system for processing vestibular information about head-in-space movement consists mainly of the reciprocally interconnected areas PIVC and 3aV, and most likely of border regions of area 2 and 7ant. This "inner cortical vestibular circuit" also receives signals from two other cortical sensory systems, the somatosensory-proprioceptive system mediated by the primary somatosensory cortex and the visual movement system (optokinetic or visual flow signals). These visual movement signals reach PIVC via area 19 and area T3.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Cortico-cortical connections and cytoarchitectonics of the primate vestibular cortex: a study in squirrel monkeys (Saimiri sciureus). 128 45

The organization of corticocortical connections in the representation of the forepaw in cat primary somatosensory cortex (SI) was studied following injections of various tracers into different cortical cytoarchitectonic areas. Small injections of horseradish peroxidase, wheat germ agglutinin-conjugated HRP, Phaseolus vulgaris leukoagglutinin, or fast blue were placed into the representation of the forepaw in areas 3b, 1, or 2. The positions of labeled neurons in SI and the surrounding cortical areas were plotted on flattened surface reconstructions to determine the organization of the corticocortical connections within SI. A strong, reciprocal projection linked the two forepaw representations which have been described in area 3b and the part of area 2 which lies in the anterior bank of the lateral ansate sulcus (see Iwamura and Tanaka 1978a, b). Dense projections also linked these areas with SII, as previously reported (Burton and Kopf 1984a). Additional projections to area 3b arose primarily from areas 3a and 1. Projections to area 2 were more widespread than those to area 3b, and arose from all other areas of SI as well as from areas 4 and 5a. All injections into SI tended to label groups of neurons which lay in mediolateral strips. Corticocortical projection neurons which were most heavily labeled by SI injections were pyramidal cells in layer III. Additional projections from area 2 to 3b, area 5a to 2, and SII to areas 2 and 3b arose from layer VI as well. Although neurons of layers III and VI were always the most densely labeled, large injections into SI labeled neurons in layers II and V as well.
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PMID:Corticocortical connections of cat primary somatosensory cortex. 128 90


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