Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.4.24.59 (MIP)
 4,906 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We have examined the origin and topography of cortical projections to area PO, an extrastriate visual area located in the parieto-occipital sulcus of the macaque. Distinguishable retrograde fluorescent tracers were injected into area PO at separate retinotopic loci identified by single-neuron recording. The results indicate that area PO receives retinotopically organized inputs from visual areas V1, V2, V3, V4, and MT. In each of these areas the projection to PO arises from the representation of the periphery of the visual field. This finding is consistent with neurophysiological data indicating that the representation of the periphery is emphasized in PO. Additional projections arise from area MST, the frontal eye fields, and several divisions of parietal cortex, including four zones within the intraparietal sulcus and a region on the medial dorsal surface of the hemisphere (MDP). On the basis of the laminar distribution of labeled cells we conclude that area PO receives an ascending input from V1, V2, and V3 and receives descending or lateral inputs from all other areas. Thus, area PO is at approximately the same level in the hierarchy of visual areas as areas V4 and MT. Area PO is connected both directly and indirectly, via MT and MST, to parietal cortex. Within parietal cortex, area PO is linked to particular regions of the intraparietal sulcus including VIP and LIP and two newly recognized zones termed here MIP and PIP. The wealth of connections with parietal cortex suggests that area PO provides a relatively direct route over which information concerning the visual field periphery can be transmitted from striate and prestriate cortex to parietal cortex. In contrast, area PO has few links with areas projecting to inferior temporal cortex. The pattern of connections revealed in this study is consistent with the view that area PO is primarily involved in visuospatial functioning.
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PMID:Topographical organization of cortical afferents to extrastriate visual area PO in the macaque: a dual tracer study. 245 34

Parietal cortex contains multiple representations of visual space. Single neurons in area LIP encode attended locations relative to the fovea, while some VIP neurons encode stimulus location relative to the head and some MIP neurons may encode location relative to the arm. These multiple representations are tailored to guide specific kinds of actions: eye movements, head movements and arm movements, respectively. The function of parietal cortex is to signal the location of attended objects relative to the observer. It does so in order to allow the organism to act on its environment. The many different kinds of actions that can be performed are likely to be supported by these very different kinds of spatial representations.
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PMID:Spatial representations for action in parietal cortex. 904 76

Recording studies in the parietal cortex have demonstrated single-unit activity in relation to sensory stimulation and during movement. We have performed three experiments to assess the effect of selective parietal lesions on sensory motor transformations. Animals were trained on two reaching tasks: reaching in the light to visual targets and reaching in the dark to targets defined by arm position. The third task assessed non-standard, non-spatial stimulus response mapping; in the conditional motor task animals were trained to either pull or turn a joystick on presentation of either a red or a blue square. We made two different lesions in the parietal cortex in two groups of monkeys. Three animals received bilateral lesions of areas 5, 7b and MIP, which have direct connections with the premotor and motor cortices. The three other animals subsequently received bilateral lesions in areas 7a, 7ab and LIP. Both groups were still able to select between movements arbitrarily associated with non-spatial cues in the conditional motor task. Removal of areas 7a, 7ab and LIP caused marked inaccuracy in reaching in the light to visual targets but had no effect on reaching in the dark. Removal of areas 5, 7b and MIP caused misreaching in the dark but had little effect on reaching in the light. The results suggest that the two divisions of the parietal cortex organize limb movements in distinct spatial coordinate systems. Area 7a/7ab/LIP is essential for spatial coordination of visual motor transformations. Area 5/7b/MIP is essential for the spatial coordination of arm movements in relation to proprioceptive and efference copy information. Neither part of the parietal lobe appears to be important for the non-standard, non-spatial transformations of response selection.
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PMID:Parietal cortex and movement. I. Movement selection and reaching. 941 75

Lesions in the two divisions of parietal cortex, 5/7b/MIP and 7a/LIP, produce dissociable reaching deficits. Monkeys with 5/7b/MIP removals were tested on reaching in the dark under two different conditions. All the reaches made on any day were from the same starting position to the same target position in the control condition. In the "transfer" condition, all the reaches were made to the same target position but consecutive reaches were made from different starting positions. The target could be represented as a constant pattern of joint and muscle positions in the control condition. The transfer condition required a representation of the starting position of the hand and/or a representation of the target in terms of its position in space. Removal of areas 5, 7b and MIP produced only a very mild impairment in the control condition and a severe impairment in the transfer condition. This suggests that 5/7b/MIP does not represent the limb in simple sensory or motor coordinates but in terms of its spatial position.
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PMID:Parietal cortex and movement. II. Spatial representation. 941 76

The ipsilateral association connections of the cortex of the dorsal part of the rostral bank of the parieto-occipital sulcus and of the adjoining posterior part of the superior parietal lobule were studied by using different retrograde fluorescent tracers. Fluoro-Ruby, Fast blue and Diamidino yellow were injected into visual area V6A, and dorso-caudal (PMdc, F2) and dorso-rostral (PMdr, F7) premotor cortex, respectively. The parietal area of injection had been previously characterized physiologically in behaving monkeys, through a variety of oculomotor and visuomanual tasks. Area V6A is mainly linked by reciprocal projections to parietal areas 7m, MIP (medial intraparietal) and PEa, and, to a lesser extent, to frontal areas PMdr (rostral dorsal premotor cortex, F7) and PMdc (F2). All these areas project to that part of the dorsocaudal premotor cortex that has a direct access to primary motor cortex. V6A is also connected to area F5 and, to a lesser extent, to 7a, ventral (VIP) and lateral (LIP) intraparietal areas. This pattern of association connections may explain the presence of visually-related and eye-position signals in premotor cortex, as well as the influence of information concerning arm position and movement direction on V6A neural activity. Area V6A emerges as a potential 'early' node of the distributed network underlying visually-guided reaching. In this network, reciprocal association connections probably impose, through re-entrant signalling, a recursive property to the operations leading to the composition of eye and hand motor commands.
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PMID:Early coding of reaching: frontal and parietal association connections of parieto-occipital cortex. 1051 Jan 99

Classic and current parcellations of the posterior parietal cortex are reviewed. Whereas earlier studies relied on subjective observation of cortical cytoarchitecture, present parcellations are mostly based on connectional and physiological criteria. These criteria have led to the identification of five areas in the intraparietal sulcus with alleged visual function: VIP, MIP, PIP, AIP, and LIP. Other visual parietal areas are 7a, in the lateral parietal surface, and, in the medial parietal wall, 7m, and V6A. Present knowledge of the dimensions, boundaries, and connections of the various visual parietal areas is uneven: whereas LIP, 7a, and 7m have been extensively explored in anatomical and physiological studies, only scant information is available for most of the intraparietal areas. It is suggested that future studies address the anatomical and functional parcellation of the posterior parietal cortex using manifold objective means of study that allow comparison by independent researchers.
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PMID:The visual parietal areas in the macaque monkey: current structural knowledge and ignorance. 1137 28

To identify subdivisions of the human parietal cortex, we collected fMRI data while ten subjects performed six tasks: grasping, pointing, saccades, attention, calculation, and phoneme detection. Examination of task intersections revealed a systematic anterior-to-posterior organization of activations associated with grasping only, grasping and pointing, all visuomotor tasks, attention and saccades, and saccades only. Calculation yielded two distinct activations: one unique to calculation in the bilateral anterior IPS mesial to the supramarginal gyrus and the other shared with phoneme detection in the left IPS mesial to the angular gyrus. These results suggest human homologs of the monkey areas AIP, MIP, V6A, and LIP and imply a large cortical expansion of the inferior parietal lobule correlated with the development of human language and calculation abilities.
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PMID:Topographical layout of hand, eye, calculation, and language-related areas in the human parietal lobe. 1183 20

The human pathogenic fungus Candida albicans, which can reside as a benign commensal of the gut, possesses a large family of lipase encoding genes whose extracellular activity may be important for colonization and subsequent infection. The expression of the C. albicans lipase gene family (LIP1-10) was investigated using a mouse model of mucosal candidiasis during alimentary tract colonization (cecum contents) and orogastric infection. LIPs4-8 were expressed in nearly every sample prepared from the cecum contents and infected mucosal tissues (stomach, hard palate, esophagus and tongue) suggesting a maintenance function for these gene products. In contrast, LIPs1, 3, and 9, which were detected consistently in infected gastric tissues, were essentially undetectable in infected oral tissues. In addition, LIP2 was expressed consistently in cecum contents but was undetectable in infected oral tissues suggesting LIP2 may be important for alimentary tract colonization, but not oral infection. The host responded to a C. albicans infection by significantly increasing expression of the chemokines MIP-2 and KC at the site of infection. Therefore, differential LIP gene expression was observed during colonization, infection and at different infected mucosal sites.
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PMID:Differential Candida albicans lipase gene expression during alimentary tract colonization and infection. 1576 91

The integration of visual and auditory events is thought to require a joint representation of visual and auditory space in a common reference frame. We investigated the coding of visual and auditory space in the lateral and medial intraparietal areas (LIP, MIP) as a candidate for such a representation. We recorded the activity of 275 neurons in LIP and MIP of two monkeys while they performed saccades to a row of visual and auditory targets from three different eye positions. We found 45% of these neurons to be modulated by the locations of visual targets, 19% by auditory targets, and 9% by both visual and auditory targets. The reference frame for both visual and auditory receptive fields ranged along a continuum between eye- and head-centered reference frames with approximately 10% of auditory and 33% of visual neurons having receptive fields that were more consistent with an eye- than a head-centered frame of reference and 23 and 18% having receptive fields that were more consistent with a head- than an eye-centered frame of reference, leaving a large fraction of both visual and auditory response patterns inconsistent with both head- and eye-centered reference frames. The results were similar to the reference frame we have previously found for auditory stimuli in the inferior colliculus and core auditory cortex. The correspondence between the visual and auditory receptive fields of individual neurons was weak. Nevertheless, the visual and auditory responses were sufficiently well correlated that a simple one-layer network constructed to calculate target location from the activity of the neurons in our sample performed successfully for auditory targets even though the weights were fit based only on the visual responses. We interpret these results as suggesting that although the representations of space in areas LIP and MIP are not easily described within the conventional conceptual framework of reference frames, they nevertheless process visual and auditory spatial information in a similar fashion.
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PMID:Eye-centered, head-centered, and complex coding of visual and auditory targets in the intraparietal sulcus. 1616 86

In primates, the frontal eye field (FEF) contains separate representations of saccadic and smooth-pursuit eye movements. The smooth-pursuit region (FEFsem) in macaque monkeys lies principally in the fundus and deep posterior wall of the arcuate sulcus, between the FEF saccade region (FEFsac) in the anterior wall and somatomotor areas on the posterior wall and convexity. In this study, cortical afferents to FEFsem were mapped by injecting retrograde tracers (WGA-HRP and fast blue) into electrophysiologically identified FEFsem sites in two monkeys. In the frontal lobe, labeled neurons were found mostly on the ipsilateral side in the (1) supplementary eye field region and lateral area F7; (2) area F2 along the superior limb of the arcuate sulcus; and (3) in the buried cortex of the arcuate sulcus extending along the superior and inferior limbs and including FEFsac and adjacent areas 8, 45, and PMv. Labeled cells were also found in the caudal periprincipal cortex (area 46) in one monkey. Labeled cells were found bilaterally in the frontal lobe in the deep posterior walls of the arcuate sulcus and postarcuate spurs and in cingulate motor areas 24 and 24c. In postcentral cortical areas all labeling was ipsilateral and there were two major foci of labeled cells: (1) the depths of the intraparietal sulcus including areas VIP, LIP, and PEa, and (2) the anterior wall and fundus of the superior temporal sulcus including areas PP and MST. Smaller numbers of labeled cells were found in superior temporal sulcal areas FST, MT, and STP, posterior cingulate area 23b, area 3a within the central sulcus, areas SII, RI, Tpt in the lateral sulcus, and parietal areas 7a, 7b, PEc, MIP, DP, and V3A. Many of these posterior afferent cortical areas code visual-motion (MT, MST, and FST) or visual-motion and vestibular (PP, VIP) signals, consistent with the responses of neurons in FEFsem and with the overall physiology and anatomy of the smooth-pursuit eye movement system.
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PMID:Cortical afferents to the smooth-pursuit region of the macaque monkey's frontal eye field. 1594 Apr 95


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