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Query: UNIPROT:P50583 (asymmetrical)
 12,197 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In Arterial hypertension abnormalities of left ventricular filling are constant and appear at an early stage, and in most cases signs of left ventricular failure (LVF) precede alterations in the left ventricular systolic function. The purpose of this study was to evaluate the frequency as well as the clinical and echocardiographic characteristics of LVF with normal systolic function in permanent arterial hypertension. 113 permanently hypertensive patients with normal left ventricular performance at echocardiography were studied clinically (functional class, congestive signs of LVF and/or presystolic gallop) and by means of echocardiographic recordings (dimensions of the left ventricle, mitral EF slope, left atrial diameter). The left ventricular wall thickness was normal (less than or equal to 11 mm) in 31 patients (group I), increased with asymmetrical septal hypertrophy in 36 patients (group II) and diffusely and symmetrically increased in 46 patients (group III). The EF slope was significantly smaller and left atrial dilatation was significantly more frequent in groups II and III than in group I. Clinical signs of LIF and presystolic gallop were observed in only groups II and III. Clinical LVF was found in 33/113 hypertensive patients (29%) and was always accompanied by symmetrical or asymmetrical left ventricular mural hypertrophy. Moreover, presystolic gallop (n = 8, i.e. 24%) and left atrial dilatation were significantly more frequent in patients with LVF than in those without LVF. Thus, LVF with normal systolic function is frequent in permanent hypertension. It results exclusively from abnormalities of left ventricular relaxation and/or compliance.
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PMID:[Incidence and clinical and echocardiographic characteristics of left ventricular insufficiency with normal systolic function in permanent arterial hypertension]. 250 96

We confirm previous evidence indicating that word length has a substantial effect on word recognition in the LVF but a much weaker effect in both the RVF and fovea. The nature of encoding in the LVF is not altered when the words are vertically displayed (Experiment 2), and the effect cannot therefore be entirely due to scanning artefact or acuity gradients in peripheral vision. We provide evidence that links the asymmetrical influence of word length directly to hemispheric specialization: left-handers, who as a group are much less consistently lateralized than right-handers are also less affected by word length in the LVF on the average (Experiment 3). This occurs because the asymmetry for certain left-handers is either very weak or, in some cases, is the complete reverse of the asymmetry observed in right-handers. Finally, we demonstrate that the length x field interaction is observed in lexical decisions (Experiment 4) which do not entail pronunciation of written words. There is some indication that concrete, high-imageable words produce a smaller effect of length in the LVF than abstract, low-imageable words, and we discuss this outcome in relation to the proposal that the right hemisphere can sometimes extract a lexical code from letter information. The concept of distinct modes of word recognition in the LVF and RVF clarifies a number of issues in laterality research, and suggests a new approach to evaluating group differences in half-field performance.
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PMID:Different modes of word recognition in the left and right visual fields. 334 18

Twenty undergraduate men participated in a short-term recognition memory experiment in which single words of four types, classified by high and low imagery value and high and low Thorndike-Lorge frequency, were each presented twice unilaterally to the right and left visual fields (RVF, LVF). Stimuli were projected either to the same or to the opposite visual field on successive presentations. Results showed that: (1) imagery value affected responses to initial presentations, but not to repetitions; and (2) the speed and accuracy of recognizing repetitions in the LVF were the same whether the stimuli had been presented initially to the LVF or the RVF, whereas speed and accuracy in the RVF were significantly poorer for words initially presented to the LVF than for words initially presented to the RVF. The latter findings are consistent with differential encoding or with asymmetrical storage of verbal information in the two hemispheres, but not with the hypothesis that the memory store for words is confined to the language-dominant hemisphere.
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PMID:Interhemispheric effects in short-term recognition memory for single words. 718 28

The ability to direct covert visual spatial attention to the left (LVF) and right visual field (RVF) was examined in 15 patients with mild to moderate Alzheimer's disease and 15 age- and education-matched controls using the covert orienting of visual spatial attention task (COVAT) modified to include both spatial and non-spatial cues. Subjects responded with a button press when they detected a target at a location 8 degrees to either the left or right of fixation. On 70% of trials a spatial cue was flashed at the target location before the target appeared. On 15% of trials the spatial cue was flashed at the location contralateral to where it would appear and on the remaining 15% of trials non-spatial diffuse cue preceded targets. The cue to target interval (CTI) varied between 150 and 550 ms. Mean reaction times for each cuetype in the RVF and LVF were calculated. Compared with controls, the percentage of trials excluded because of very slow reaction times was significantly greater in the Alzheimer's disease group for the 550 ms CTI. Analysis of the symmetry of reaction times to LVF and RVF targets for the 150 ms CTI enabled us to classify Alzheimer's disease subjects into three subgroups based on the hemifield of abnormally slow attentional biases. The first subgroup showed a significant slowing of reaction time to all LVF targets, the second showed a significant slowing of reaction time to all RVF targets and the third showed a significant slowing of reaction time to both LVF and RVF targets. Patients with Alzheimer's disease who showed an abnormal attentional bias performed significantly better on neuropsychological tests of memory, language and executive function than Alzheimer's disease patients with no attentional bias. Eight of the Alzheimer's disease subjects were assessed serially on at least six occasions over a 12-month period. The initial classification of abnormal attentional bias or no attentional bias was reliable for seven Alzheimer's disease subjects. One Alzheimer's disease subject, initially classified as having a slowed rightward attentional bias, in subsequent testing over the 12-month period was more consistent with symmetrical COVAT performance. Control subjects showed no attentional biases over the 12-month period and the magnitude of asymmetric attentional slowing over the 12-month period was significantly more variable in individual Alzheimer's disease subjects than in controls. The presence of subgroups of patients with Alzheimer's disease with qualitatively different COVAT performance indicates a large between-subject variability in attentional deficits in Alzheimer's disease. The presence of asymmetric attentional slowing and milder neuropsychological deficits in a subgroup of patients with Alzheimer's disease suggests that in these patients there is functional impairment of attentional areas in only one hemisphere rather than an asymmetric impairment of both hemispheres and that the neurodegenerative disease process may have been less advanced or in an earlier stage than that present in Alzheimer's disease patients with symmetric attentional performance and bilateral COVAT impairment. The preservation of asymmetric attentional slowing over time, together with the increased intra-subject variability in the magnitude of these asymmetries, suggests that asymmetrical COVAT performance represents a reliable reflection of underlying hemispheric function in Alzheimer's disease, although designation of asymmetrical attentional biases should be made on the basis of two or more sequential testing sessions.
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PMID:Asymmetries in the covert orienting of visual spatial attention to spatial and non-spatial cues in Alzheimer's disease. 859 74

In our previous event-related potential (ERP) study [A. Nowicka, I. Szatkowska, Memory-induced modulation of event-related potentials in frontal cortex of human subjects: a divided visual field study, Neurosci. Lett. 359 (2004) 171-174], word repetition effects in right-handed males were observed only in case of the direct stimulation of the left (competent) hemisphere. Since the left-handedness and the factor of female gender may determine the lateralization of verbal functions, the goal of the present study was to test the sensitivity of the ERP repetition effects to the visual field of word presentation in the group of left- and right-handed women. ERPs were recorded from symmetrical sites over the left and right hemisphere. Target words were presented in the left (LVF) or right (RVF) visual hemifield. Subjects' were instructed to recognize the target word on a response card. A substantial portion of words was repeated twice. Words elicited different ERPs at frontal sites when presented the first and second times: ERPs were more positive to the repeated stimulus than to its first occurrence. However, in right-handed participants, repetition effects were only observed when target words were presented to the RVF whereas in left-handed participants, repetition effects were only observed when target words were presented to the LVF. These findings are indicative of the asymmetrical involvement of the two hemispheres in memory-induced modulation of brain activity related to verbal processing in left- and right-handed women.
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PMID:Lateralization of repetition effects in event-related potentials to words in left- and right-handed women. 1622 46

The well-established right visual field (RVF-lh) advantage in word recognition is commonly attributed to the typical left hemisphere dominance in language; words presented to the LVF-rh are processed less efficiently due to the need for transcallosal transfer from the right to left hemisphere. The exact stage for this hemispheric transfer is currently unsettled. Some studies suggest that transfer occurs at very early stages between primary visual regions, whereas other studies suggest that transfer occurs between the left visual word form area and its right hemisphere homolog. This study explores these conflicting accounts and finds evidence for both. Participants conducted a lateralized lexical decision task with both unilateral and bilateral display conditions. Connectivity analyses were conducted from magnetoencephalography signals that were localized to the left middle occipital gyrus (LMOG), right middle occipital gyrus (RMOG), left visual word form area (LVWFA), and right visual word form area (RVWA). Results from unilateral trials showed asymmetrical interhemispheric connectivity from the RMOG to LMOG and symmetrical interhemispheric connectivity between the LVWFA and RVWFA. Furthermore, bilateral presentations led to reduced interhemispheric connectivity between both homologous region of interest pairs. Together, these results suggest that lateralized word recognition involves multiple stages of interhemispheric interactions and that these interactions are reduced with bilateral displays.
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PMID:Interhemispheric connectivity during lateralized lexical decision. 3037 29