Sample records for left visual hemifield

  1. Unifying Visual Space Across the Left and Right Hemifields. (United States)

    Chen, Zhimin; Kosovicheva, Anna; Wolfe, Benjamin; Cavanagh, Patrick; Gorea, Andrei; Whitney, David


    Visual space is perceived as continuous and stable even though visual inputs from the left and right visual fields are initially processed separately within the two cortical hemispheres. In the research reported here, we examined whether the visual system utilizes a dynamic recalibration mechanism to integrate these representations and to maintain alignment across the visual fields. Subjects adapted to randomly oriented moving lines that straddled the vertical meridian; these lines were vertically offset between the left and right hemifields. Subsequent vernier alignment judgments revealed a negative aftereffect: An offset in the same direction as the adaptation was required to correct the perceived misalignment. This aftereffect was specific to adaptation to vertical, but not horizontal, misalignments and also occurred following adaptation to movie clips and patterns without coherent motion. Our results demonstrate that the visual system unifies the left and right halves of visual space by continuously recalibrating the alignment of elements across the visual fields.

  2. Lateralization of spatial rather than temporal attention underlies the left hemifield advantage in rapid serial visual presentation. (United States)

    Asanowicz, Dariusz; Kruse, Lena; Śmigasiewicz, Kamila; Verleger, Rolf


    In bilateral rapid serial visual presentation (RSVP), the second of two targets, T1 and T2, is better identified in the left visual field (LVF) than in the right visual field (RVF). This LVF advantage may reflect hemispheric asymmetry in temporal attention or/and in spatial orienting of attention. Participants performed two tasks: the "standard" bilateral RSVP task (Exp.1) and its unilateral variant (Exp.1 & 2). In the bilateral task, spatial location was uncertain, thus target identification involved stimulus-driven spatial orienting. In the unilateral task, the targets were presented block-wise in the LVF or RVF only, such that no spatial orienting was needed for target identification. Temporal attention was manipulated in both tasks by varying the T1-T2 lag. The results showed that the LVF advantage disappeared when involvement of stimulus-driven spatial orienting was eliminated, whereas the manipulation of temporal attention had no effect on the asymmetry. In conclusion, the results do not support the hypothesis of hemispheric asymmetry in temporal attention, and provide further evidence that the LVF advantage reflects right hemisphere predominance in stimulus-driven orienting of spatial attention. These conclusions fit evidence that temporal attention is implemented by bilateral parietal areas and spatial attention by the right-lateralized ventral frontoparietal network. Copyright © 2017 Elsevier Inc. All rights reserved.

  3. Competitive interactions of attentional resources in early visual cortex during sustained visuospatial attention within or between visual hemifields: evidence for the different-hemifield advantage. (United States)

    Walter, Sabrina; Quigley, Cliodhna; Mueller, Matthias M


    Performing a task across the left and right visual hemifields results in better performance than in a within-hemifield version of the task, termed the different-hemifield advantage. Although recent studies used transient stimuli that were presented with long ISIs, here we used a continuous objective electrophysiological (EEG) measure of competitive interactions for attentional processing resources in early visual cortex, the steady-state visual evoked potential (SSVEP). We frequency-tagged locations in each visual quadrant and at central fixation by flickering light-emitting diodes (LEDs) at different frequencies to elicit distinguishable SSVEPs. Stimuli were presented for several seconds, and participants were cued to attend to two LEDs either in one (Within) or distributed across left and right visual hemifields (Across). In addition, we introduced two reference measures: one for suppressive interactions between the peripheral LEDs by using a task at fixation where attention was withdrawn from the periphery and another estimating the upper bound of SSVEP amplitude by cueing participants to attend to only one of the peripheral LEDs. We found significantly greater SSVEP amplitude modulations in Across compared with Within hemifield conditions. No differences were found between SSVEP amplitudes elicited by the peripheral LEDs when participants attended to the centrally located LEDs compared with when peripheral LEDs had to be ignored in Across and Within trials. Attending to only one LED elicited the same SSVEP amplitude as Across conditions. Although behavioral data displayed a more complex pattern, SSVEP amplitudes were well in line with the predictions of the different-hemifield advantage account during sustained visuospatial attention.

  4. Hemispheric differences in electrical and hemodynamic responses during hemifield visual stimulation with graded contrasts. (United States)

    Si, Juanning; Zhang, Xin; Zhang, Yujin; Jiang, Tianzi


    A multimodal neuroimaging technique based on electroencephalography (EEG) and functional near-infrared spectroscopy (fNIRS) was used with horizontal hemifield visual stimuli with graded contrasts to investigate the retinotopic mapping more fully as well as to explore hemispheric differences in neuronal activity, the hemodynamic response, and the neurovascular coupling relationship in the visual cortex. The fNIRS results showed the expected activation over the contralateral hemisphere for both the left and right hemifield visual stimulations. However, the EEG results presented a paradoxical lateralization, with the maximal response located over the ipsilateral hemisphere but with the polarity inversed components located over the contralateral hemisphere. Our results suggest that the polarity inversion as well as the latency advantage over the contralateral hemisphere cause the amplitude of the VEP over the contralateral hemisphere to be smaller than that over the ipsilateral hemisphere. Both the neuronal and hemodynamic responses changed logarithmically with the level of contrast in the hemifield visual stimulations. Moreover, the amplitudes and latencies of the visual evoked potentials (VEPs) were linearly correlated with the hemodynamic responses despite differences in the slopes.

  5. Stronger interference from distractors in the right hemifield during visual search. (United States)

    Carlei, Christophe; Kerzel, Dirk


    The orientation-bias hypothesis states that there is a bias to attend to the right visual hemifield (RVF) when there is spatial competition between stimuli in the left and right hemifield [Pollmann, S. (1996). A pop-out induced extinction-like phenomenon in neurologically intact subjects. Neuropsychologia, 34(5), 413-425. doi: 10.1016/0028-3932(95)00125-5 ]. In support of this hypothesis, stronger interference was reported for RVF distractors with contralateral targets. In contrast, previous studies using rapid serial visual presentation (RSVP) found stronger interference from distractors in the left visual hemifield (LVF). We used the additional singleton paradigm to test whether this discrepancy was due to the different distractor features that were employed (colour vs. orientation). Interference from the colour distractor with contralateral targets was larger in the RVF than in the LVF. However, the asymmetrical interference disappeared when observers had to search for an inconspicuous colour target instead of the inconspicuous shape target. We suggest that the LVF orienting-bias is limited to situations where search is driven by bottom-up saliency (singleton search) instead of top-down search goals (feature search). In contrast, analysis of the literature suggests the opposite for the LVF bias in RSVP tasks. Thus, the attentional asymmetry may depend on whether the task involves temporal or spatial competition, and whether search is based on bottom-up or top-down signals.

  6. A Case of Functional (Psychogenic Monocular Hemianopia Analyzed by Measurement of Hemifield Visual Evoked Potentials

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    Tsuyoshi Yoneda


    Full Text Available Purpose: Functional monocular hemianopia is an extremely rare condition, for which measurement of hemifield visual evoked potentials (VEPs has not been previously described. Methods: A 14-year-old boy with functional monocular hemianopia was followed up with Goldmann perimetry and measurement of hemifield and full-field VEPs. Results: The patient had a history of monocular temporal hemianopia of the right eye following headache, nausea and ague. There was no relative afferent pupillary defect, and a color perception test was normal. Goldmann perimetry revealed a vertical monocular temporal hemianopia of the right eye; the hemianopia on the right was also detected with a binocular visual field test. Computed tomography, magnetic resonance imaging (MRI and MR angiography of the brain including the optic chiasm as well as orbital MRI revealed no abnormalities. On the basis of these results, we diagnosed the patient's condition as functional monocular hemianopia. Pattern VEPs according to the International Society for Clinical Electrophysiology of Vision (ISCEV standard were within the normal range. The hemifield pattern VEPs for the right eye showed a symmetrical latency and amplitude for nasal and temporal hemifield stimulation. One month later, the visual field defect of the patient spontaneously disappeared. Conclusions: The latency and amplitude of hemifield VEPs for a patient with functional monocular hemianopia were normal. Measurement of hemifield VEPs may thus provide an objective tool for distinguishing functional hemianopia from hemifield loss caused by an organic lesion.

  7. Left, right, left, right, eyes to the front! Müller-Lyer bias in grasping is not a function of hand used, hand preferred or visual hemifield, but foveation does matter.

    NARCIS (Netherlands)

    van der Kamp, J.; de Wit, M.M.; Masters, R.S.W.


    We investigated whether the control of movement of the left hand is more likely to involve the use of allocentric information than movements performed with the right hand. Previous studies (Gonzalez et al. in J Neurophys 95:3496-3501, 2006; De Grave et al. in Exp Br Res 193:421-427, 2009) have

  8. Impact of lower- vs. upper-hemifield presentation on automatic colour-deviance detection: a visual mismatch negativity study. (United States)

    Müller, Dagmar; Roeber, Urte; Winkler, István; Trujillo-Barreto, Nelson; Czigler, István; Schröger, Erich


    The automatic processing of deviances from the temporal context of the visual environment has become an important topic in visual cognitive sciences, which is often investigated using the visual mismatch negativity (vMMN). This event-related potential (ERP) component is elicited by an irregular stimulus (e.g., a red disc) presented in a series of stimuli (e.g., green discs) comprising a temporal regularity (e.g., colour repetition). We determined the influence of lower- vs. upper-hemifield presentation of the irregular stimulus on the vMMN while using whole-field stimulus displays controlling for sustained shifts in spatial attention. Deviances presented in the lower hemifield elicited a larger vMMN than the ones presented in the upper hemifield at a latency of 200-280ms. However, this asymmetry was preceded by deviance-related hemifield effects already emerging at an earlier latency (110-150ms), where upper-hemifield deviances elicited a positive potential but lower-hemifield deviances did not. With variable resolution electromagnetic tomography (VARETA) early deviance-related activity was localised to retinotopically organised regions of the visual cortex (BA 17/18) and vMMN-sources were localised to the middle/superior occipital gyrus, to higher areas along the temporal visual stream, but also to BA 17/18. We argue that the upper/lower-hemifield vMMN asymmetry relies at least partially on the hemifield-dependent differential sensitivity of early deviance-related activity generated in retinotopically organised regions of the visual cortex. However, a superior automatic processing of deviances presented in the lower visual hemifield may also contribute to the effect. Copyright © 2012 Elsevier B.V. All rights reserved.

  9. Classification of Targets and Distractors Present in Visual Hemifields Using Time-Frequency Domain EEG Features

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    Full Text Available This paper presents a classification system to classify the cognitive load corresponding to targets and distractors present in opposite visual hemifields. The approach includes the study of EEG (electroencephalogram signal features acquired in a spatial attention task. The process comprises of EEG feature selection based on the feature distribution, followed by the stepwise discriminant analysis- (SDA- based channel selection. Repeated measure analysis of variance (rANOVA is applied to test the statistical significance of the selected features. Classifiers are developed and compared using the selected features to classify the target and distractor present in visual hemifields. The results provide a maximum classification accuracy of 87.2% and 86.1% and an average classification accuracy of 76.5 ± 4% and 76.2 ± 5.3% over the thirteen subjects corresponding to the two task conditions. These correlates present a step towards building a feature-based neurofeedback system for visual attention.

  10. Asymmetrical Brain Activity Induced by Voluntary Spatial Attention Depends on the Visual Hemifield: A Functional Near-Infrared Spectroscopy Study (United States)

    Harasawa, Masamitsu; Shioiri, Satoshi


    The effect of the visual hemifield to which spatial attention was oriented on the activities of the posterior parietal and occipital visual cortices was examined using functional near-infrared spectroscopy in order to investigate the neural substrates of voluntary visuospatial attention. Our brain imaging data support the theory put forth in a…

  11. Degraded transfer of memories between the visual hemifields in normal macaques revealed by a novel infrared eyetracking method without head fixation. (United States)

    Wilson, Charles R E; Buckley, Mark J; Gaffan, David


    Electrophysiological evidence in macaque monkeys indicates that when the monkey views a visual scene with objects present in both visual hemifields, the cells of the temporal lobe respond to objects in the contralateral field, but are hardly affected by objects in the ipsilateral field. If visual memories are stored in the temporal lobes, as is generally believed, then this implies that the transfer of visual object memories from one hemifield to the other should either fail or at least suffer decrement. Building on a previous study in human subjects, we tested this prediction in rhesus monkeys (Macaca mulatta). We developed a method for tracking the eye movements of the awake, behaving monkey, which does not require the monkey to be restrained or surgically prepared. We optimised the system to provide reliable feedback of eye position in real time, and so provide hemifield-specific presentation of visual objects. In each acquisition phase the monkeys learned several object discriminations concurrently, each object only ever being presented to one hemifield, and with an object present in each hemifield on every trial. In subsequent transfer tests with the same objects, the monkeys performed significantly worse when the objects were shifted to the opposite hemifield than if shifted the same distance within one hemifield. Thus, in monkeys as well as in humans, and in association learning as well as in recognition memory, visual memories can be to a large extent hemifield-specific. This result shows that, like perceptual systems, mnemonic systems of the temporal lobe are largely hemifield-specific, and this has clear implications for studies of the temporal lobes. Further, the validation of our method will allow us to use it, in future experiments, to investigate in monkeys the effects of specific unilateral lesions on visual perception and memory for objects that are presented in known positions in the visual field. (c) 2010 Elsevier Ltd. All rights reserved.

  12. Illusory conjunctions in visual short-term memory: Individual differences in corpus callosum connectivity and splitting attention between the two hemifields. (United States)

    Qin, Shuo; Ray, Nicholas R; Ramakrishnan, Nithya; Nashiro, Kaoru; O'Connell, Margaret A; Basak, Chandramallika


    Overloading the capacity of visual attention can result in mistakenly combining the various features of an object, that is, illusory conjunctions. We hypothesize that if the two hemispheres separately process visual information by splitting attention, connectivity of corpus callosum-a brain structure integrating the two hemispheres-would predict the degree of illusory conjunctions. In the current study, we assessed two types of illusory conjunctions using a memory-scanning paradigm; the features were either presented across the two opposite hemifields or within the same hemifield. Four objects, each with two visual features, were briefly presented together followed by a probe-recognition and a confidence rating for the recognition accuracy. MRI scans were also obtained. Results indicated that successful recollection during probe recognition was better for across hemifields conjunctions compared to within hemifield conjunctions, lending support to the bilateral advantage of the two hemispheres in visual short-term memory. Age-related differences regarding the underlying mechanisms of the bilateral advantage indicated greater reliance on recollection-based processing in young and on familiarity-based processing in old. Moreover, the integrity of the posterior corpus callosum was more predictive of opposite hemifield illusory conjunctions compared to within hemifield illusory conjunctions, even after controlling for age. That is, individuals with lesser posterior corpus callosum connectivity had better recognition for objects when their features were recombined from the opposite hemifields than from the same hemifield. This study is the first to investigate the role of the corpus callosum in splitting attention between versus within hemifields. © 2016 Society for Psychophysiological Research.

  13. Hemifield effects in multiple identity tracking.

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    Charlotte Hudson

    Full Text Available In everyday life, we often need to attentively track moving objects. A previous study has claimed that this tracking occurs independently in the left and right visual hemifields (Alvarez & Cavanagh, 2005, Psychological Science,16, 637-647. Specifically, it was shown that observers were much more accurate at tracking objects that were spread over both visual hemifields as opposed to when all were confined to a single visual hemifield. In that study, observers were not required to remember the identities of the objects. Conversely, in real life, there is seldom any benefit to tracking an object unless you can also recall its identity. It has been predicted that when observers are required to remember the identities of the tracked objects a bilateral advantage should no longer be observed (Oksama & Hyönä, 2008, Cognitive Psychology, 56, 237-283. We tested this prediction and found that a bilateral advantage still occurred, though it was not as strong as when observers were not required to remember the identities of the targets. Even in the later case we found that tracking was not completely independent in the two visual hemifields. We present a combined model of multiple object tracking and multiple identity tracking that can explain our data.

  14. Hemifield Asymmetry in the Potency of Exogenous Auditory and Visual Cues


    Sosa, Yamaya; Clarke, Aaron M.; McCourt, Mark E.


    Neurologically normal subjects misperceive the midpoints of lines (PSE) as reliably leftward of veridical center, a phenomenon known as pseudoneglect. This leftward bias reflects the dominance of the right cerebral hemisphere in deploying spatial attention. Transient visual cues, delivered to either the left or right endpoints of lines, modulate PSE such that leftward biases are increased by leftward cues, and are decreased by rightward cues, relative to a no-cue control condition. We ask whe...

  15. The role of hemifield sector analysis in multifocal visual evoked potential objective perimetry in the early detection of glaucomatous visual field defects

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    Mousa MF


    Full Text Available Mohammad F Mousa,1 Robert P Cubbidge,2 Fatima Al-Mansouri,1 Abdulbari Bener3,41Department of Ophthalmology, Hamad Medical Corporation, Doha, Qatar; 2School of Life and Health Sciences, Aston University, Birmingham, UK; 3Department of Medical Statistics and Epidemiology, Hamad Medical Corporation, Department of Public Health, Weill Cornell Medical College, Doha, Qatar; 4Department Evidence for Population Health Unit, School of Epidemiology and Health Sciences, University of Manchester, Manchester, UKObjective: The purpose of this study was to examine the effectiveness of a new analysis method of mfVEP objective perimetry in the early detection of glaucomatous visual field defects compared to the gold standard technique.Methods and patients: Three groups were tested in this study; normal controls (38 eyes, glaucoma patients (36 eyes, and glaucoma suspect patients (38 eyes. All subjects underwent two standard 24-2 visual field tests: one with the Humphrey Field Analyzer and a single mfVEP test in one session. Analysis of the mfVEP results was carried out using the new analysis ­protocol: the hemifield sector analysis protocol.Results: Analysis of the mfVEP showed that the signal to noise ratio (SNR difference between superior and inferior hemifields was statistically significant between the three groups (analysis of variance, P < 0.001 with a 95% confidence interval, 2.82, 2.89 for normal group; 2.25, 2.29 for glaucoma suspect group; 1.67, 1.73 for glaucoma group. The difference between superior and inferior hemifield sectors and hemi-rings was statistically significant in 11/11 pair of sectors and hemi-rings in the glaucoma patients group (t-test P < 0.001, statistically significant in 5/11 pairs of sectors and hemi-rings in the glaucoma suspect group (t-test P < 0.01, and only 1/11 pair was statistically significant (t-test P < 0.9. The sensitivity and specificity of the hemifield sector analysis protocol in detecting glaucoma was 97% and 86

  16. Visual mismatch negativity (vMMN) is elicited with para-foveal hemifield oddball stimulation: An event-related brain potential (ERP) study. (United States)

    Berti, Stefan


    The visual mismatch negativity (vMMN) is a component of the human event-related brain potential (ERP) that indicates the automatic processing and detection of changes in the visual sensory input. The study tested whether the vMMN was observable when the visual input is restricted to one visual hemifield and, with this, only para-foveal input to one of the two primary sensory cortices in the visual system is available for stimulus processing. The vMMN was elicited by the stimulation restricted to a small portion of the visual field. This demonstrates that in general vMMN elicitation is not confined to stimulations covering a broad range of the visual field or to the propagation of sensory information to both sensory visual cortices. In addition, the vMMN amplitudes showed a high variability between the different conditions, including non-significant vMMN amplitudes. This suggests that pronounced vMMNs observed in experimental settings relies on salient visual stimuli covering different channels of sensory information in vision. Copyright © 2018 Elsevier B.V. All rights reserved.

  17. Long-term effects of serial anodal tDCS on motion perception in subjects with occipital stroke measured in the unaffected visual hemifield

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    Manuel C Olma


    Full Text Available Transcranial direct current stimulation (tDCS is a novel neuromodulatory tool that has seen early transition to clinical trials, although the high variability of these findings necessitates further studies in clincally-relevant populations. The majority of evidence into effects of repeated tDCS is based on research in the human motor system, but it is unclear whether the long-term effects of serial tDCS are motor-specific or transferable to other brain areas. This study aimed to examine whether serial anodal tDCS over the visual cortex can exogenously induce long-term neuroplastic changes in the visual cortex. However, when the visual cortex is affected by a cortical lesion, up-regulated endogenous neuroplastic adaptation processes may alter the susceptibility to tDCS. To this end, motion perception was investigated in the unaffected hemifield of subjects with unilateral visual cortex lesions. Twelve subjects with occipital ischaemic lesions participated in a within-subject, sham-controlled, double-blind study. MRI-registered sham or anodal tDCS (1.5 mA, 20 minutes was applied on five consecutive days over the visual cortex. Motion perception was tested before and after stimulation sessions and at 14- and 28-day follow-up. After a 16-day interval an identical study block with the other stimulation condition (anodal or sham tDCS followed. Serial anodal tDCS over the visual cortex resulted in an improvement in motion perception, a function attributed to MT/V5. This effect was still measurable at 14- and 28-day follow-up measurements. Thus, this may represent evidence for long-term tDCS-induced plasticity and has implications for the design of studies examining the time course of tDCS effects in both the visual and motor systems.

  18. Effects of visual-field and matching instruction on event-related potentials and reaction time.

    NARCIS (Netherlands)

    Kok, A.; van de Vijver, R.; Bouma, A.


    Vertical letter pairs were presented randomly in the left and right visual hemifields of 20 right-handed male undergraduates in physical-identity match and name-identity match conditions. Reaction times (RTs) showed a right visual-field superiority for name matches and a left visual-field

  19. Symbolic representation and visual querying of left ventricular image sequences. (United States)

    Baroni, M; Del Bimbo, A; Evangelist, A; Vicario, E


    In the evaluation of regional left ventricular function, relevant cardiac disorders manifest themselves not only in static features, such as shape descriptors and motion excursion in end-diastolic and end-systolic frames, but also in their temporal evolution. In common diagnostic practice, such dynamic patterns are analysed by direct inspection of frame sequences through the use of a moviola. This permits only a subjective and poorly defined evaluation of functional parameters, and definitely prevents a systematic and reproducible analysis of large sets of reports. Retrieval by contents techniques may overcome this limitation by permitting the automatic comparison of the reports in a database against queries expressing descriptive properties related to significant pathological conditions. A system is presented which is aimed at investigating the potential of this approach by supporting retrieval by contents from a database of cineangiographic or echocardiographic images. The system relies on a symbolic description of both geometrical and temporal properties of left ventricular contours. This is derived automatically by an image processing and interpretation module and associated with the report at its storage time. In the retrieval stage, queries are expressed by means of an iconic visual language which describes searched content properties over a computer screen. The system automatically interprets iconic statements and compares them against concrete descriptions in the database. This enables medical users to interact with the system to search for motion and shape abnormalities on a regional basis, in single or homogeneous groups of reports, so as to enable both prospective and retrospective diagnosis.

  20. Exploring the temporal dynamics of sustained and transient spatial attention using steady-state visual evoked potentials. (United States)

    Zhang, Dan; Hong, Bo; Gao, Shangkai; Röder, Brigitte


    While the behavioral dynamics as well as the functional network of sustained and transient attention have extensively been studied, their underlying neural mechanisms have most often been investigated in separate experiments. In the present study, participants were instructed to perform an audio-visual spatial attention task. They were asked to attend to either the left or the right hemifield and to respond to deviant transient either auditory or visual stimuli. Steady-state visual evoked potentials (SSVEPs) elicited by two task irrelevant pattern reversing checkerboards flickering at 10 and 15 Hz in the left and the right hemifields, respectively, were used to continuously monitor the locus of spatial attention. The amplitude and phase of the SSVEPs were extracted for single trials and were separately analyzed. Sustained attention to one hemifield (spatial attention) as well as to the auditory modality (intermodal attention) increased the inter-trial phase locking of the SSVEP responses, whereas briefly presented visual and auditory stimuli decreased the single-trial SSVEP amplitude between 200 and 500 ms post-stimulus. This transient change of the single-trial amplitude was restricted to the SSVEPs elicited by the reversing checkerboard in the spatially attended hemifield and thus might reflect a transient re-orienting of attention towards the brief stimuli. Thus, the present results demonstrate independent, but interacting neural mechanisms of sustained and transient attentional orienting.

  1. Impairments of Gestalt perception in the intact hemifield of hemianopic patients are reflected in gamma-band EEG activity. (United States)

    Schadow, Jeanette; Dettler, Nicole; Paramei, Galina V; Lenz, Daniel; Fründ, Ingo; Sabel, Bernhard A; Herrmann, Christoph S


    Gamma-band responses (GBRs) are associated with Gestalt perception processes. In the present EEG study, we investigated the effects of perceptual grouping on the visual GBR in the perimetrically intact visual field of patients with homonymous hemianopia and compared them to healthy participants. All observers were presented either random arrays of Gabor elements or arrays with an embedded circular arrangement. For the hemianopic patients, the circle was presented in their intact hemifield only. For controls, the hemifield for the circle presentation was counterbalanced across subjects. The participants were instructed to detect the circle by pressing a corresponding button. A wavelet transform based on Morlet wavelets was employed for the calculation of oscillatory GBRs. The early evoked GBR exhibited a larger amplitude and shorter latency for the healthy group compared to hemianopic patients and was associated with behavioral measures. The late total GBR between 200 and 400ms after stimulus onset was significantly increased for Gestalt-like patterns in healthy participants. This effect was not manifested in patients. The present findings indicate deficits in the early and late visual processing of Gestalt patterns even in the intact hemifield of hemianopic patients compared to healthy participants.

  2. Saccade performance in the nasal and temporal hemifields

    DEFF Research Database (Denmark)

    Jóhannesson, Ómar Ingi; Ásgeirsson, Árni Gunnar; Kristjánsson, Árni


    differences for saccadic eye movements. There is also evidence for stronger retinotectal neural projection from the nasal than the temporal he- miretina. There is, accordingly, good reason to predict asymmetries in saccadic performance depending on which hemifield the saccade trigger stimuli are presented in...... is surprising in light of previous findings of attentional asymmetries, it may reflect that cortical input to midbrain eye control centers mitigates any retinal and retinotectal asymmetry....

  3. Detour behaviour in attack-trained dogs: left-turners perform better than right-turners. (United States)

    Siniscalchi, Marcello; Pergola, Gianluca; Quaranta, Angelo


    Detour behaviour was investigated in attack-trained dogs faced with a "U"-shaped vertical barrier behind which a figurant (target) was located. Left-turners took less time to detour the barrier than right-turners. The most logical explanation for the lateral asymmetries observed in dogs' detour behaviour is to assume that they reflect preferential use of the right or the left eye in visual analysis of the target. Given that the lateral field of each eye of dogs projects mainly to the contralateral side of the brain, shorter latencies to solve the task observed in left-turners (right visual hemifield) with respect to right-turners (left visual hemifield) are consistent with specialisation of the left hemisphere in prey-catching behaviour. Overall our results supported previous evidence that cerebral lateralisation in vertebrates can directly affect visually guided motor responses and have practical implications for personnel involved in the selection of dogs trained specifically to assist police and other law-enforcement personnel in their work.

  4. Visual attention in posterior stroke

    DEFF Research Database (Denmark)

    Fabricius, Charlotte; Petersen, Anders; Iversen, Helle K

    Objective: Impaired visual attention is common following strokes in the territory of the middle cerebral artery, particularly in the right hemisphere. However, attentional effects of more posterior lesions are less clear. The aim of this study was to characterize visual processing speed...... and apprehension span following posterior cerebral artery (PCA) stroke. We also relate these attentional parameters to visual word recognition, as previous studies have suggested that reduced visual speed and span may explain pure alexia. Methods: Nine patients with MR-verified focal lesions in the PCA......-territory (four left PCA; four right PCA; one bilateral, all >1 year post stroke) were compared to 25 controls using single case statistics. Visual attention was characterized by a whole report paradigm allowing for hemifield-specific speed and span measurements. We also characterized visual field defects...

  5. A Bilateral Advantage for Storage in Visual Working Memory (United States)

    Umemoto, Akina; Drew, Trafton; Ester, Edward F.; Awh, Edward


    Various studies have demonstrated enhanced visual processing when information is presented across both visual hemifields rather than in a single hemifield (the "bilateral advantage"). For example, Alvarez and Cavanagh (2005) reported that observers were able to track twice as many moving visual stimuli when the tracked items were presented…

  6. Visualization of Fiber Structure in the Left and Right Ventricle of a Human Heart

    International Nuclear Information System (INIS)

    Rohmer, Damien; Sitek, Arkadiusz; Gullberg, Grant T.


    The human heart is composed of a helical network of muscle fibers. Anisotropic least squares filtering followed by fiber tracking techniques were applied to Diffusion Tensor Magnetic Resonance Imaging(DTMRI) data of the excised human heart. The fiber configuration was visualized by using thin tubes to increase 3-dimensional visual perception of the complex structure. All visualizations were performed using the high-quality ray-tracing software POV-Ray. The fibers are shown within the left and right ventricles. Both ventricles exhibit similar fiber architecture and some bundles of fibers are shown linking right and left ventricles on the posterior region of the heart

  7. The left visual-field advantage in rapid visual presentation is amplified rather than reduced by posterior-parietal rTMS

    DEFF Research Database (Denmark)

    Verleger, Rolf; Möller, Friderike; Kuniecki, Michal


    In the present task, series of visual stimuli are rapidly presented left and right, containing two target stimuli, T1 and T2. In previous studies, T2 was better identified in the left than in the right visual field. This advantage of the left visual field might reflect dominance exerted...... by the right over the left hemisphere. If so, then repetitive transcranial magnetic stimulation (rTMS) to the right parietal cortex might release the left hemisphere from right-hemispheric control, thereby improving T2 identification in the right visual field. Alternatively or additionally, the asymmetry in T2......) either as effective or as sham stimulation. In two experiments, either one of these two factors, hemisphere and effectiveness of rTMS, was varied within or between participants. Again, T2 was much better identified in the left than in the right visual field. This advantage of the left visual field...

  8. Recognition of emotion in hemifaces presented to the left and right visual fields. (United States)

    Wedding, D; Cyrus, P


    Thirty-two right-handed subjects (16 males and 16 females) participated in a choice reaction time experiment replicating two previous studies which demonstrated the superiority of the left hemisphere in rapidly identifying facial emotion as either positive or negative. Slides of hemifaces split along the vertical axis, showing either positive (happiness, surprise) or negative (anger, disgust, or sadness) affect were presented tachistoscopically to either the left or right visual field. A 2 X 2 X 2 mixed ANOVA revealed main effects for visual field and type of affect. In contrast to earlier studies which presented full face stimuli, presentation of hemifaces produced a strong left visual field advantage and, as expected, positive faces produced faster reaction times than negative faces.

  9. Defining the real-world reproducibility of visual grading of left ventricular function and visual estimation of left ventricular ejection fraction: impact of image quality, experience and accreditation. (United States)

    Cole, Graham D; Dhutia, Niti M; Shun-Shin, Matthew J; Willson, Keith; Harrison, James; Raphael, Claire E; Zolgharni, Massoud; Mayet, Jamil; Francis, Darrel P


    Left ventricular function can be evaluated by qualitative grading and by eyeball estimation of ejection fraction (EF). We sought to define the reproducibility of these techniques, and how they are affected by image quality, experience and accreditation. Twenty apical four-chamber echocardiographic cine loops (Online Resource 1-20) of varying image quality and left ventricular function were anonymized and presented to 35 operators. Operators were asked to provide (1) a one-phrase grading of global systolic function (2) an "eyeball" EF estimate and (3) an image quality rating on a 0-100 visual analogue scale. Each observer viewed every loop twice unknowingly, a total of 1400 viewings. When grading LV function into five categories, an operator's chance of agreement with another operator was 50% and with themself on blinded re-presentation was 68%. Blinded eyeball LVEF re-estimates by the same operator had standard deviation (SD) of difference of 7.6 EF units, with the SD across operators averaging 8.3 EF units. Image quality, defined as the average of all operators' assessments, correlated with EF estimate variability (r = -0.616, p visual grading agreement (r = 0.58, p visual grading of LV function and LVEF estimation is dependent on image quality, but individuals cannot themselves identify when poor image quality is disrupting their LV function estimate. Clinicians should not assume that patients changing in grade or in visually estimated EF have had a genuine clinical change.

  10. TMS over the right precuneus reduces the bilateral field advantage in visual short term memory capacity. (United States)

    Kraft, Antje; Dyrholm, Mads; Kehrer, Stefanie; Kaufmann, Christian; Bruening, Jovita; Kathmann, Norbert; Bundesen, Claus; Irlbacher, Kerstin; Brandt, Stephan A


    Several studies have demonstrated a bilateral field advantage (BFA) in early visual attentional processing, that is, enhanced visual processing when stimuli are spread across both visual hemifields. The results are reminiscent of a hemispheric resource model of parallel visual attentional processing, suggesting more attentional resources on an early level of visual processing for bilateral displays [e.g. Sereno AB, Kosslyn SM. Discrimination within and between hemifields: a new constraint on theories of attention. Neuropsychologia 1991;29(7):659-75.]. Several studies have shown that the BFA extends beyond early stages of visual attentional processing, demonstrating that visual short term memory (VSTM) capacity is higher when stimuli are distributed bilaterally rather than unilaterally. Here we examine whether hemisphere-specific resources are also evident on later stages of visual attentional processing. Based on the Theory of Visual Attention (TVA) [Bundesen C. A theory of visual attention. Psychol Rev 1990;97(4):523-47.] we used a whole report paradigm that allows investigating visual attention capacity variability in unilateral and bilateral displays during navigated repetitive transcranial magnetic stimulation (rTMS) of the precuneus region. A robust BFA in VSTM storage capacity was apparent after rTMS over the left precuneus and in the control condition without rTMS. In contrast, the BFA diminished with rTMS over the right precuneus. This finding indicates that the right precuneus plays a causal role in VSTM capacity, particularly in bilateral visual displays. Copyright © 2015 Elsevier Inc. All rights reserved.

  11. Influence of script direction on word processing modes in left and right visual fields. (United States)

    Siéroff, Eric; Slama, Yael


    Word processing in left (LVF) and right (RVF) visual fields may be affected by left hemisphere activation during reading and by script direction. We evaluated the effect of script direction by presenting words in left-to-right (French) and right-to-left (Hebrew) scripts to bilingual French participants. Words of different lengths were presented in the LVF and the RVF in a naming task. Results showed (1) a stronger word length effect in the LVF than in the RVF in French, and no difference of word length effect between LVF and RVF in Hebrew; (2) a first-letter advantage only in the LVF in French and in the RVF in Hebrew, showing an effect of script direction on letter processing; and (3) a stronger advantage of external over internal letters in words presented in the LVF than in the RVF for both languages, showing a left hemisphere influence on letter activation. Thus, script direction and left hemisphere activation may affect different processes when reading words in LVF and RVF. Selective attention may orient and redistribute a processing "window" over the letter string according to script direction, and the modulation of attentional resources is influenced by left hemisphere activation.

  12. Left Global Hemineglect in High Autism-Spectrum Quotient Individuals

    Directory of Open Access Journals (Sweden)

    Daniel Paul Crewther


    Full Text Available Autism remains as a significant issue for many individuals due to the social impairment accompanying the disorder. Recent theories present potential relationships between autistic tendency and visual perceptual differences to explore differences in underlying visual pathways. These differences have been explored though the use of global and local stimuli to show difference in perception. This study compared the balance of global versus local perception between sub-groups from the normal population both high and low on the Autism Spectrum Quotient (AQ. A diamond illusion task containing rivaling global and local percepts was used to explore the effects of changing the occluder contrast and peripheral viewing upon global/local percept. An increase in global perception relative to increasing eccentricity of the stimulus from a fixation point was also seen in both groups. However, with increasing contrast of the occluding stripes both groups showed an increase in the percentage of global perception. When comparing between groups the high AQ showed a significant reduction in global perception compared to the low AQ group when the stimulus was presented in left hemifield. This difference wasn't present within right hemifield. We discuss how global perceptual hemineglect may suggest abnormal parietal function in individuals with high AQ.

  13. Emergence of realism: Enhanced visual artistry and high accuracy of visual numerosity representation after left prefrontal damage. (United States)

    Takahata, Keisuke; Saito, Fumie; Muramatsu, Taro; Yamada, Makiko; Shirahase, Joichiro; Tabuchi, Hajime; Suhara, Tetsuya; Mimura, Masaru; Kato, Motoichiro


    Over the last two decades, evidence of enhancement of drawing and painting skills due to focal prefrontal damage has accumulated. It is of special interest that most artworks created by such patients were highly realistic ones, but the mechanism underlying this phenomenon remains to be understood. Our hypothesis is that enhanced tendency of realism was associated with accuracy of visual numerosity representation, which has been shown to be mediated predominantly by right parietal functions. Here, we report a case of left prefrontal stroke, where the patient showed enhancement of artistic skills of realistic painting after the onset of brain damage. We investigated cognitive, functional and esthetic characteristics of the patient׳s visual artistry and visual numerosity representation. Neuropsychological tests revealed impaired executive function after the stroke. Despite that, the patient׳s visual artistry related to realism was rather promoted across the onset of brain damage as demonstrated by blind evaluation of the paintings by professional art reviewers. On visual numerical cognition tasks, the patient showed higher performance in comparison with age-matched healthy controls. These results paralleled increased perfusion in the right parietal cortex including the precuneus and intraparietal sulcus. Our data provide new insight into mechanisms underlying change in artistic style due to focal prefrontal lesion. Copyright © 2014 Elsevier Ltd. All rights reserved.

  14. Left visual neglect: is the disengage deficit space- or object-based? (United States)

    Rastelli, Federica; Funes, Maria-Jesus; Lupiáñez, Juan; Duret, Christophe; Bartolomeo, Paolo


    Attention can be directed to spatial locations or to objects in space. Patients with left unilateral spatial neglect are slow to respond to a left-sided target when it is preceded by a right-sided "invalid" cue, particularly at short cue-target intervals, suggesting an impairment in disengaging attention from the right side in order to orient it leftward. We wondered whether this deficit is purely spatial, or it is influenced by the presence of a right-sided visual object. To answer this question, we tested 10 right brain-damaged patients with chronic left-neglect and 41 control participants on a cued response time (RT) detection task in which targets could appear in either of two lateral boxes. In different conditions, non-informative peripheral cues either consisted in the brightening of the contour of one lateral box (onset cue condition), or in the complete disappearance of one lateral box (offset cue condition). The target followed the cue at different stimulus-onset asynchronies (SOAs). If the disengagement deficit (DD) is purely space-based, then it should not vary across the two cueing conditions. With onset cues, patients showed a typical DD at short SOAs. With offset cues, however, the DD disappeared. Thus, patients did not show any DD when there was no object from which attention must be disengaged. These findings indicate that the attentional bias in left-neglect does not concern spatial locations per se, but visual objects in space.

  15. Cerebral Asymmetry of fMRI-BOLD Responses to Visual Stimulation

    DEFF Research Database (Denmark)

    Hougaard, Anders; Jensen, Bettina Hagström; Amin, Faisal Mohammad


    was correlated with subject age, suggesting a shift towards the left hemisphere with increasing age. Our findings suggest a right-hemispheric dominance of these areas, which could lend support to the generally observed leftward visual attentional bias and to the left hemifield advantage for some visual......Hemispheric asymmetry of a wide range of functions is a hallmark of the human brain. The visual system has traditionally been thought of as symmetrically distributed in the brain, but a growing body of evidence has challenged this view. Some highly specific visual tasks have been shown to depend...... on hemispheric specialization. However, the possible lateralization of cerebral responses to a simple checkerboard visual stimulation has not been a focus of previous studies. To investigate this, we performed two sessions of blood-oxygenation level dependent (BOLD) functional magnetic resonance imaging (f...

  16. Effects of spatial attention on motion discrimination are greater in the left than right visual field. (United States)

    Bosworth, Rain G; Petrich, Jennifer A F; Dobkins, Karen R


    In order to investigate differences in the effects of spatial attention between the left visual field (LVF) and the right visual field (RVF), we employed a full/poor attention paradigm using stimuli presented in the LVF vs. RVF. In addition, to investigate differences in the effects of spatial attention between the dorsal and ventral processing streams, we obtained motion thresholds (motion coherence thresholds and fine direction discrimination thresholds) and orientation thresholds, respectively. The results of this study showed negligible effects of attention on the orientation task, in either the LVF or RVF. In contrast, for both motion tasks, there was a significant effect of attention in the LVF, but not in the RVF. These data provide psychophysical evidence for greater effects of spatial attention in the LVF/right hemisphere, specifically, for motion processing in the dorsal stream. Published by Elsevier Ltd.

  17. Categorical Perception of Colour in the Left and Right Visual Field Is Verbally Mediated: Evidence from Korean (United States)

    Roberson, Debi; Pak, Hyensou; Hanley, J. Richard


    In this study we demonstrate that Korean (but not English) speakers show Categorical perception (CP) on a visual search task for a boundary between two Korean colour categories that is not marked in English. These effects were observed regardless of whether target items were presented to the left or right visual field. Because this boundary is…

  18. Reading laterally: the cerebral hemispheric use of spatial frequencies in visual word recognition. (United States)

    Tadros, Karine; Dupuis-Roy, Nicolas; Fiset, Daniel; Arguin, Martin; Gosselin, Frédéric


    It is generally accepted that the left hemisphere (LH) is more capable for reading than the right hemisphere (RH). Left hemifield presentations (initially processed by the RH) lead to a globally higher error rate, slower word identification, and a significantly stronger word length effect (i.e., slower reaction times for longer words). Because the visuo-perceptual mechanisms of the brain for word recognition are primarily localized in the LH (Cohen et al., 2003), it is possible that this part of the brain possesses better spatial frequency (SF) tuning for processing the visual properties of words than the RH. The main objective of this study is to determine the SF tuning functions of the LH and RH for word recognition. Each word image was randomly sampled in the SF domain using the SF bubbles method (Willenbockel et al., 2010) and was presented laterally to the left or right visual hemifield. As expected, the LH requires less visual information than the RH to reach the same level of performance, illustrating the well-known LH advantage for word recognition. Globally, the SF tuning of both hemispheres is similar. However, these seemingly identical tuning functions hide important differences. Most importantly, we argue that the RH requires higher SFs to identify longer words because of crowding.

  19. Affective priming of emotional pictures in parafoveal vision: left visual field advantage. (United States)

    Calvo, Manuel G; Avero, Pedro


    This study investigated whether stimulus affective content can be extracted from visual scenes when these appear in parafoveal locations of the visual field and are foveally masked, and whether there is lateralization involved. Parafoveal prime pleasant or unpleasant scenes were presented for 150 msec 2.5 degrees away from fixation and were followed by a foveal probe scene that was either congruent or incongruent in emotional valence with the prime. Participants responded whether the probe was emotionally positive or negative. Affective priming was demonstrated by shorter response latencies for congruent than for incongruent prime-probe pairs. This effect occurred when the prime was presented in the left visual field at a 300-msec prime-probe stimulus onset asynchrony, even when the prime and the probe were different in physical appearance and semantic category. This result reveals that the affective significance of emotional stimuli can be assessed early through covert attention mechanisms, in the absence of overt eye fixations on the stimuli, and suggests that right-hemisphere dominance is involved.

  20. Position matching between the visual fields in strabismus. (United States)

    Hussain, Zahra; Astle, Andrew T; Webb, Ben S; McGraw, Paul V


    The misalignment of visual input in strabismus disrupts positional judgments. We measured positional accuracy in the extrafoveal visual field (1°-7° eccentricity) of a large group of strabismic subjects and a normal control group to identify positional distortions associated with the direction of strabismus. Subjects performed a free localization task in which targets were matched in opposite hemifields whilst fixating on a central cross. The constant horizontal error of each response was taken as a measure of accuracy, in addition to radial and angular error. In monocular conditions, all stimuli were viewed by one eye; thus, the error reflected spatial bias. In dichoptic conditions, the targets were seen by separate eyes; thus, the error reflected the perceived stimulus shift produced by ocular misalignment in addition to spatial bias. In both viewing conditions, both groups showed reliable over- and underestimations of visual field position, here termed a compression of response coordinates. The normal group showed compression in the left periphery, regardless of eye of stimulation. The strabismic group showed a visual field-specific compression that was clearly associated with direction of strabismus. The variation in perceived shift of strabismic subjects was largely accounted for by the biases present in monocular viewing, suggesting that binocular correspondence was uniform in the tested region. The asymmetric strabismic compression could not be reproduced in normal subjects through prism viewing, and its presence across viewing conditions suggests a hemifield-specific change in spatial coding induced by long-standing ocular misalignment.

  1. Task difficulty reduces the left visual hemispace bias for judgments of emotion in chimeric faces. (United States)

    Carbary, Timothy J; Almerigi, Jason B; Harris, Lauren Julius


    A prior study (Carbary, Almerigi, & Harris, 2001) of adults' judgments of emotional chimeric faces showed that the left visual hemispace (LVH) bias normally found on a free-viewing chimeric faces test is reduced when the task is judged to be difficult. Taking into account theory and research on hemispheric differences in styles, or strategies, of information processing, we proposed that the reduction was related to a change in these strategies. Two new experiments are presented that independently manipulate task difficulty and show the same task difficulty-related effect as in our prior study. Data are also presented suggesting that the strategy most commonly adopted for difficult judgments is part-based or feature-oriented, whereas the strategy most commonly adopted for easy judgments is reliance on "first impression."

  2. Electroencephalographic (eeg coherence between visual and motor areas of the left and the right brain hemisphere while performing visuomotor task with the right and the left hand

    Directory of Open Access Journals (Sweden)

    Simon Brežan


    Full Text Available Background: Unilateral limb movements are based on the activation of contralateral primary motor cortex and the bilateral activation of premotor cortices. Performance of a visuomotor task requires a visuomotor integration between motor and visual cortical areas. The functional integration (»binding« of different brain areas, is probably mediated by the synchronous neuronal oscillatory activity, which can be determined by electroencephalographic (EEG coherence analysis. We introduced a new method of coherence analysis and compared coherence and power spectra in the left and right hemisphere for the right vs. left hand visuomotor task, hypothesizing that the increase in coherence and decrease in power spectra while performing the task would be greater in the contralateral hemisphere.Methods: We analyzed 6 healthy subjects and recorded their electroencephalogram during visuomotor task with the right or the left hand. For data analysis, a special Matlab computer programme was designed. The results were statistically analysed by a two-way analysis of variance, one-way analysis of variance and post-hoc t-tests with Bonferroni correction.Results: We demonstrated a significant increase in coherence (p < 0.05 for the visuomotor task compared to control tasks in alpha (8–13 Hz in beta 1 (13–20 Hz frequency bands between visual and motor electrodes. There were no significant differences in coherence nor power spectra depending on the hand used. The changes of coherence and power spectra between both hemispheres were symmetrical.Conclusions: In previous studies, a specific increase of coherence and decrease of power spectra for the visuomotor task was found, but we found no conclusive asymmetries when performing the task with right vs. left hand. This could be explained in a way that increases in coherence and decreases of power spectra reflect symmetrical activation and cooperation between more complex visual and motor brain areas.

  3. On the advantage of being left-handed in volleyball: further evidence of the specificity of skilled visual perception. (United States)

    Loffing, Florian; Schorer, Jörg; Hagemann, Norbert; Baker, Joseph


    High ball speeds and close distances between competitors require athletes in interactive sports to correctly anticipate an opponent's intentions in order to render appropriate reactions. Although it is considered crucial for successful performance, such skill appears impaired when athletes are confronted with a left-handed opponent, possibly because of athletes' reduced perceptual familiarity with rarely encountered left-handed actions. To test this negative perceptual frequency effect hypothesis, we invited 18 skilled and 18 novice volleyball players to predict shot directions of left- and right-handed attacks in a video-based visual anticipation task. In accordance with our predictions, and with recent reports on laterality differences in visual perception, the outcome of left-handed actions was significantly less accurately predicted than the outcome of right-handed attacks. In addition, this left-right bias was most distinct when predictions had to be based on preimpact (i.e., before hand-ball contact) kinematic cues, and skilled players were generally more affected by the opponents' handedness than were novices. The study's findings corroborate the assumption that skilled visual perception is attuned to more frequently encountered actions.

  4. Flow Visualization Studies in the Novacor Left Ventricular Assist System CRADA PC91-002, Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Borovetz, H.S.; Shaffer, F.; Schaub, R.; Lund, L.; Woodard, J.


    This paper discusses a series of experiments to visualize and measure flow fields in the Novacor left ventricular assist system (LVAS). The experiments utilize a multiple exposure, optical imaging technique called fluorescent image tracking velocimetry (FITV) to hack the motion of small, neutrally-buoyant particles in a flowing fluid.

  5. Left neglected, but only in far space: Spatial biases in healthy participants revealed in a visually-guided grasping task

    Directory of Open Access Journals (Sweden)

    Natalie ede Bruin


    Full Text Available Hemispatial neglect is a common outcome of stroke that is characterised by the inability to orient towards, and attend to stimuli in contralesional space. It is established that hemispatial neglect has a perceptual component, however, the presence and severity of motor impairments is controversial. Establishing the nature of space use and spatial biases during visually-guided actions amongst healthy individuals is critical to understanding the presence of visuomotor deficits in patients with neglect. Accordingly, three experiments were conducted to investigate the effect of object spatial location on patterns of grasping. Experiment 1 required right-handed participants to reach and grasp for blocks in order to construct 3D models. The blocks were scattered on a tabletop divided into equal size quadrants: left near, left far, right near, and right far. Identical sets of building blocks were available in each quadrant. Space use was dynamic, with participants initially grasping blocks from right near space and tending to ‘neglect’ left far space until the final stages of the task. Experiment 2 repeated the protocol with left-handed participants. Remarkably, left-handed participants displayed a similar pattern of space use to right-handed participants. In Experiment 3 eye movements were examined to investigate whether ‘neglect’ for grasping in left far reachable space had its origins in attentional biases. It was found that patterns of eye movements mirrored patterns of reach-to-grasp movements. We conclude that there are spatial biases during visually-guided grasping, specifically, a tendency to neglect left far reachable space, and that this ‘neglect’ is attentional in origin. The results raise the possibility that visuomotor impairments reported among patients with right hemisphere lesions when working in contralesional space may result in part from this inherent tendency to ‘neglect’ left far space irrespective of the presence

  6. Right away: A late, right-lateralized category effect complements an early, left-lateralized category effect in visual search. (United States)

    Constable, Merryn D; Becker, Stefanie I


    According to the Sapir-Whorf hypothesis, learned semantic categories can influence early perceptual processes. A central finding in support of this view is the lateralized category effect-namely, the finding that categorically different colors (e.g., blue and green hues) can be discriminated faster than colors within the same color category (e.g., different hues of green), especially when they are presented in the right visual field. Because the right visual field projects to the left hemisphere, this finding has been popularly couched in terms of the left-lateralization of language. However, other studies have reported bilateral category effects, which has led some researchers to question the linguistic origins of the effect. Here we examined the time course of lateralized and bilateral category effects in the classical visual search paradigm by means of eyetracking and RT distribution analyses. Our results show a bilateral category effect in the manual responses, which is combined of an early, left-lateralized category effect and a later, right-lateralized category effect. The newly discovered late, right-lateralized category effect occurred only when observers had difficulty locating the target, indicating a specialization of the right hemisphere to find categorically different targets after an initial error. The finding that early and late stages of visual search show different lateralized category effects can explain a wide range of previously discrepant findings.

  7. Positive schizotypy scores correlate with left visual field interference for negatively valenced emotional words: A lateralized emotional Stroop study. (United States)

    Van Strien, Jan W; Van Kampen, Dirk


    Fourteen men scoring high and 14 men scoring low on a positive schizotypy scale participated in a lateralized emotional Stroop task. Vocal reaction times for color naming of neutral, positive and negative emotional words were recorded. Across participants, the color naming of neutral and emotional words was slightly faster to right than to left visual field presentations. In men with high scores on positive schizotypy, the presentation of negative words to the left visual field (right hemisphere) resulted in significant affective interference with color naming, which was significantly larger than in men with low scores. Correlational analysis also showed that positive schizotypy was significantly associated with emotional interference in response to LVF negative words. The outcome is discussed in terms of right hemispheric engagement in negative emotions in high positive schizotypic men.

  8. Visualization and simulated surgery of the left ventricle in the virtual pathological heart of the Virtual Physiological Human (United States)

    McFarlane, N. J. B.; Lin, X.; Zhao, Y.; Clapworthy, G. J.; Dong, F.; Redaelli, A.; Parodi, O.; Testi, D.


    Ischaemic heart failure remains a significant health and economic problem worldwide. This paper presents a user-friendly software system that will form a part of the virtual pathological heart of the Virtual Physiological Human (VPH2) project, currently being developed under the European Commission Virtual Physiological Human (VPH) programme. VPH2 is an integrated medicine project, which will create a suite of modelling, simulation and visualization tools for patient-specific prediction and planning in cases of post-ischaemic left ventricular dysfunction. The work presented here describes a three-dimensional interactive visualization for simulating left ventricle restoration surgery, comprising the operations of cutting, stitching and patching, and for simulating the elastic deformation of the ventricle to its post-operative shape. This will supply the quantitative measurements required for the post-operative prediction tools being developed in parallel in the same project. PMID:22670207

  9. Embedded Words in Visual Word Recognition: Does the Left Hemisphere See the Rain in Brain? (United States)

    McCormick, Samantha F.; Davis, Colin J.; Brysbaert, Marc


    To examine whether interhemispheric transfer during foveal word recognition entails a discontinuity between the information presented to the left and right of fixation, we presented target words in such a way that participants fixated immediately left or right of an embedded word (as in "gr*apple", "bull*et") or in the middle…

  10. Diagnostic ability of retinal nerve fiber layer thickness measurements and neurologic hemifield test to detect chiasmal compression. (United States)

    Moon, Chan Hee; Lee, Si Hyung; Kim, Bum-Tae; Hwang, Sun Chul; Ohn, Young-Hoon; Park, Tae Kwann


    The purpose of the study was to investigate the diagnostic ability of the neurologic hemifield test (NHT) and retinal nerve fiber layer (RNFL) thickness measurements to detect chiasmal compression. Thirty-seven patients with chiasmal compression, 35 patients with glaucoma, and 30 patients with glaucoma suspect were enrolled. The NHT score was established from a 30-2 visual field pattern deviation probability plot. Each test point value was calculated for a number that was inversely proportional to its pattern deviation probability. The NHT score was the absolute value of the difference in the sum of the point scores for two symmetrical regions of 16 points on either side of the vertical meridian. RNFL thickness was scored from 0 to 10 according to the pattern of RNFL loss and probability of abnormality. Solely present nasal or temporal RNFL defects were scored high, and exclusively appearing superior or nasal RNFL defects were scored low. The differences in the NHT and RNFL scores among the three groups were compared. Diagnostic ability was assessed by receiver operating characteristic (ROC) analysis. The NHT and RNFL scores were significantly higher in patients with chiasmal compression than in patients with glaucoma and glaucoma suspect. The area under the ROC curve (AROC) was 0.734 of the NHT score and 0.613 of the RNFL score. When AROC was calculated using the NHT and RNFL scores concurrently, AROC was increased to 0.807. The NHT score and RNFL score have diagnostic ability to detect chiasmal compression, and simultaneous assessment of NHT and RNFL scores improves the diagnostic power.

  11. The impact of visual field loss on driving performance: evidence from on-road driving assessments. (United States)

    Racette, Lyne; Casson, Evanne J


    The purpose of this study was to investigate the relationship between visual field loss and driving performance as determined by on-road driving assessments. We reviewed the files of 1350 patients enrolled in a rehabilitation program at the Bloorview MacMillan Rehabilitation Centre, Toronto, Canada. We identified 131 patients with visual field loss who had undergone an on-road driving assessment. These patients had a primary diagnosis of visual impairment or a primary diagnosis of cerebral vascular accident (CVA) with a secondary diagnosis of visual impairment. None of these patients had documentation of neglect, substantial motor or cognitive deficits. We report the data obtained from 13 hemianopics, 7 quadrantanopics, 25 patients with monocular vision, 10 patients with moderate peripheral losses (worse impact on driving performance than quadrantanopia with a marginally significant result (chi2 = 3.33, p = 0.068). Overall, the location of the visual loss was not significantly related to driving fitness (chi2 = 1.05, p = 0.30). However, localized defects in the left hemifield (chi2 = 9.561, p = 0.002) and diffuse visual loss in the right hemifield (chi2 = 10.395, p = 0.001) seemed to be associated with driving impairments. A large proportion of monocular drivers were safe drivers and the location of their deficit had no significant impact. Although the extent of visual field defects appears to be related to driving performance as determined by an on-road driving assessment, large individual differences were observed. This highlights the need for individualized on-road assessments for patients with visual field defects.

  12. Transfer of an induced preferred retinal locus of fixation to everyday life visual tasks. (United States)

    Barraza-Bernal, Maria J; Rifai, Katharina; Wahl, Siegfried


    Subjects develop a preferred retinal locus of fixation (PRL) under simulation of central scotoma. If systematic relocations are applied to the stimulus position, PRLs manifest at a location in favor of the stimulus relocation. The present study investigates whether the induced PRL is transferred to important visual tasks in daily life, namely pursuit eye movements, signage reading, and text reading. Fifteen subjects with normal sight participated in the study. To develop a PRL, all subjects underwent a scotoma simulation in a prior study, where five subjects were trained to develop the PRL in the left hemifield, five different subjects on the right hemifield, and the remaining five subjects could naturally chose the PRL location. The position of this PRL was used as baseline. Under central scotoma simulation, subjects performed a pursuit task, a signage reading task, and a reading-text task. In addition, retention of the behavior was also studied. Results showed that the PRL position was transferred to the pursuit task and that the vertical location of the PRL was maintained on the text reading task. However, when reading signage, a function-driven change in PRL location was observed. In addition, retention of the PRL position was observed over weeks and months. These results indicate that PRL positions can be induced and may further transferred to everyday life visual tasks, without hindering function-driven changes in PRL position.

  13. Myocardial visualization on a routine perfusion lung scintigram: Relationship to the amount of right-to-left shunt

    International Nuclear Information System (INIS)

    Seto, H.; Futatsuya, R.; Kamei, T.; Kakishita, M.; Hisada, K.


    Three cases of myocardial visualization on a routine perfusion lung scintigram with sup(99m)Tc-macroaggregaed albumin were reported in patients with congenital heart diseases; two cases of tetralogy of Fallot and one case of truncus arteriosus type IV. Large right-to-left shunts greater than 39% and marked hypertrophy of the ventricle suggesting the presence of increased coronary blood flow were noted in all cases. In the two patients with tetralogy of Fallot myocardial activity appeared to be located in the hypertrophic right venticles. (orig.)

  14. Myocardial visualization on a routine perfusion lung scintigram: Relationship to the amount of right-to-left shunt

    Energy Technology Data Exchange (ETDEWEB)

    Seto, H.; Futatsuya, R.; Kamei, T.; Kakishita, M.; Hisada, K.


    Three cases of myocardial visualization on a routine perfusion lung scintigram with sup(99m)Tc-macroaggregated albumin were reported in patients with congenital heart diseases; two cases of tetralogy of Fallot and one case of truncus arteriosus type IV. Large right-to-left shunts greater than 39% and marked hypertrophy of the ventricle suggesting the presence of increased coronary blood flow were noted in all cases. In the two patients with tetralogy of Fallot myocardial activity appeared to be located in the hypertrophic right venticles.

  15. The spatially asymmetric cost of memory load on visual perception: transient stimulus-centered neglect. (United States)

    Gozli, Davood G; Wilson, Kristin E; Ferber, Susanne


    Recent evidence suggests that visual working memory (VWM) load reduces performance accuracy on a concurrent visual recognition task, particularly for objects presented in the left hemifield. It has also been shown that high VWM load causes suppression of activity in the right temporoparietal junction (TPJ). Given the resemblance of VWM load effects to symptoms of unilateral neglect (i.e., impaired perception on the left side and lesion to the right TPJ), we investigated whether VWM load effects are restricted to the left side of space or extend to object-centered reference frames. In other words, akin to object-centered neglect, can high VWM load cause a perceptual cost in attending to the left side of the stimulus? We addressed this question using an object recognition task (Experiment 1) and a visual search task (Experiment 2) showing that this transient left-neglect can indeed be modulated by an object-centered frame of reference. These findings suggest that load-induced impairments of visual attention are spatially asymmetric and can emerge within multiple spatial reference frames. Therefore, the attentional consequences of high VWM load on conscious perception may serve as a useful model of unilateral perceptual neglect.

  16. On computational modeling of visual saliency: Examining what's right, and what's left. (United States)

    Bruce, Neil D B; Wloka, Calden; Frosst, Nick; Rahman, Shafin; Tsotsos, John K


    In the past decade, a large number of computational models of visual saliency have been proposed. Recently a number of comprehensive benchmark studies have been presented, with the goal of assessing the performance landscape of saliency models under varying conditions. This has been accomplished by considering fixation data, annotated image regions, and stimulus patterns inspired by psychophysics. In this paper, we present a high-level examination of challenges in computational modeling of visual saliency, with a heavy emphasis on human vision and neural computation. This includes careful assessment of different metrics for performance of visual saliency models, and identification of remaining difficulties in assessing model performance. We also consider the importance of a number of issues relevant to all saliency models including scale-space, the impact of border effects, and spatial or central bias. Additionally, we consider the biological plausibility of models in stepping away from exemplar input patterns towards a set of more general theoretical principles consistent with behavioral experiments. As a whole, this presentation establishes important obstacles that remain in visual saliency modeling, in addition to identifying a number of important avenues for further investigation. Copyright © 2015 Elsevier Ltd. All rights reserved.

  17. Advocating for the Visual Arts in the Era of No Child Left Behind (United States)

    Daniel, Christine


    Research has shown that a solid visual arts program provided to students throughout the K-12 years increases academic achievement, increases self-confidence and self-concept and provides opportunities for students to tap all their intelligences. However, recent budget cuts and the high stake testing on Mathematics and English Language arts at all…

  18. Right brain, left brain in depressive disorders: Clinical and theoretical implications of behavioral, electrophysiological and neuroimaging findings. (United States)

    Bruder, Gerard E; Stewart, Jonathan W; McGrath, Patrick J


    The right and left side of the brain are asymmetric in anatomy and function. We review electrophysiological (EEG and event-related potential), behavioral (dichotic and visual perceptual asymmetry), and neuroimaging (PET, MRI, NIRS) evidence of right-left asymmetry in depressive disorders. Recent electrophysiological and fMRI studies of emotional processing have provided new evidence of altered laterality in depressive disorders. EEG alpha asymmetry and neuroimaging findings at rest and during cognitive or emotional tasks are consistent with reduced left prefrontal activity in depressed patients, which may impair downregulation of amygdala response to negative emotional information. Dichotic listening and visual hemifield findings for non-verbal or emotional processing have revealed abnormal perceptual asymmetry in depressive disorders, and electrophysiological findings have shown reduced right-lateralized responsivity to emotional stimuli in occipitotemporal or parietotemporal cortex. We discuss models of neural networks underlying these alterations. Of clinical relevance, individual differences among depressed patients on measures of right-left brain function are related to diagnostic subtype of depression, comorbidity with anxiety disorders, and clinical response to antidepressants or cognitive behavioral therapy. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. Macular and Multifocal PERG and FD-OCT in Preperimetric and Hemifield Loss Glaucoma. (United States)

    Kreuz, André C; de Moraes, Carlos G; Hatanaka, Marcelo; Oyamada, Maria K; Monteiro, Mario L R


    To evaluate the ability of macular and multifocal (mf) pattern electroretinogram (PERG) to differentiate preperimetric glaucoma (PG) and glaucoma with hemifield loss (GHL) from controls, to compare the discrimination ability of PERG and fourier-domain optical coherence tomography (FD-OCT), and to assess the relationship between measurements. Standard automated perimetry, steady-state and transient PERG and mfPERG measurements were obtained from PG (n=14, 24 eyes), GHL (n=5, 7 eyes), and controls (n=19, 22 eyes). Circumpapillary retinal nerve fiber layer (cpRNFL), full-thickness macula, and segmented macular layer thicknesses on FD-OCT were investigated. Measurements were compared using mixed effects linear models. The relationships between measurements and the diagnostic performance of each technology were assessed. Compared with controls, average P50 peak time transient PERG responses were reduced in PG and GHL, whereas average latency and amplitude steady-state and mfPERG responses were abnormal only in GHL. cpRNFL and macular thickness measurements in PG and GHL differed significantly from controls. A significant relationship was found between PERG and most FD-OCT or SAP parameters. Partial least squares discriminant analysis revealed that OCT parameters, along with mfPERG and transient PERG parameters had similar ability to discriminate PG and GHL from healthy controls. PERG and OCT parameters may be abnormal, with significant correlations between measurements, in PG eyes. Both technologies may be useful for detection of early glaucoma.

  20. Interhemispheric Transfer Time Asymmetry of Visual Information Depends on Eye Dominance: An Electrophysiological Study

    Directory of Open Access Journals (Sweden)

    Romain Chaumillon


    Full Text Available The interhemispheric transfer of information is a fundamental process in the human brain. When a visual stimulus appears eccentrically in one visual-hemifield, it will first activate the contralateral hemisphere but also the ipsilateral one with a slight delay due to the interhemispheric transfer. This interhemispheric transfer of visual information is believed to be faster from the right to the left hemisphere in right-handers. Such an asymmetry is considered as a relevant fact in the context of the lateralization of the human brain. We show here using current source density (CSD analyses of visually evoked potential (VEP that, in right-handers and, to a lesser extent in left-handers, this asymmetry is in fact dependent on the sighting eye dominance, the tendency we have to prefer one eye for monocular tasks. Indeed, in right-handers, a faster interhemispheric transfer of visual information from the right to left hemisphere was observed only in participants with a right dominant eye (DE. Right-handers with a left DE showed the opposite pattern, with a faster transfer from the left to the right hemisphere. In left-handers, albeit a smaller number of participants has been tested and hence confirmation is required, only those with a right DE showed an asymmetrical interhemispheric transfer with a faster transfer from the right to the left hemisphere. As a whole these results demonstrate that eye dominance is a fundamental determinant of asymmetries in interhemispheric transfer of visual information and suggest that it is an important factor of brain lateralization.

  1. Intra-procedure Visualization of the Esophagus using Interventional C-arm CT as Guidance for Left Atrial Radiofrequency Ablation (United States)

    Tognolini, Alessia; Al-Ahmad, Amin; Wang, Paul J.; Hsia, Henry H.; Herfkens, Robert J.; Girard, Erin; Moore, Teri; Fahrig, Rebecca


    Rational and Objectives During radiofrequency catheter ablation (RFCA) for atrial fibrillation, the esophagus is at risk for thermal injury. In this study we compared using C-arm CT to clinical CT, without administration of oral contrast, to visualize the esophagus and its relationship to the left atrium (LA) and the ostia of the pulmonary veins (PV) during the RF ablation procedure. Materials and Methods Sixteen subjects underwent both cardiac clinical CT and C-arm CT. CT scans were obtained on a multi-detector CT using a standard ECG-gated protocol. C-arm CT scans were obtained using either a multi-sweep protocol with retrospective ECG-gating or a non-gated single-sweep protocol. C-arm CT and CT scans were analyzed in a random order and then compared for the following criteria: a) visualization of the esophagus (yes/no), b) relationship of esophagus position to the 4 PVs, and c) direct contact or absence of a fat pad between the esophagus and PV antrum. Results a) The esophagus was identified in all C-arm CT and CT scans. In 4 cases, orthogonal planes were needed on C-arm CT (inferior PV level); b) In 6 patients, the esophagus location on C-arm CT was different from CT; c) Direct contact was reported in 19/64 (30%) of the segments examined on CT vs. 26/64 (41%) on C-arm CT. In 5/64 segments (8%), C-arm CT overestimated a direct contact of the esophagus to the LA. Conclusion C-arm CT image quality without administration of oral contrast agents was shown to be sufficient for visualization of the esophagus location during an RFCA procedure for atrial fibrillation. PMID:21440465

  2. Using surface imaging and visual coaching to improve the reproducibility and stability of deep-inspiration breath hold for left-breast-cancer radiotherapy

    International Nuclear Information System (INIS)

    Cervino, Laura I; Gupta, Sonia; Rose, Mary A; Yashar, Catheryn; Jiang, Steve B


    Late cardiac complications may arise after left-breast radiation therapy. Deep-inspiration breath hold (DIBH) allows reduction of the irradiated heart volume at the same time as it reduces tumor bed motion and increases lung sparing. In the present study, we have evaluated the improvement in reproducibility and stability of the DIBH for left-breast-cancer treatment when visual coaching is provided with the aid of 3D video surface imaging and video goggles. Five left-breast-cancer patients and fifteen healthy volunteers were asked to perform a series of DIBHs without and with visual coaching. Reproducibility and stability of DIBH were measured for each individual with and without visual coaching. The average reproducibility and stability changed from 2.1 mm and 1.5 mm, respectively, without visual feedback to 0.5 mm and 0.7 mm with visual feedback, showing a significant statistical difference (p 2 mm) in reproducibility and stability were observed in 35% and 15% of the subjects, respectively. The average chest wall excursion of the DIBH with respect to the free breathing preceding the DIBH was found to be 11.3 mm. The reproducibility and stability of the DIBH improve significantly from the visual coaching provided to the patient, especially in those patients with poor reproducibility and stability.

  3. Using surface imaging and visual coaching to improve the reproducibility and stability of deep-inspiration breath hold for left-breast-cancer radiotherapy (United States)

    Cerviño, Laura I.; Gupta, Sonia; Rose, Mary A.; Yashar, Catheryn; Jiang, Steve B.


    Late cardiac complications may arise after left-breast radiation therapy. Deep-inspiration breath hold (DIBH) allows reduction of the irradiated heart volume at the same time as it reduces tumor bed motion and increases lung sparing. In the present study, we have evaluated the improvement in reproducibility and stability of the DIBH for left-breast-cancer treatment when visual coaching is provided with the aid of 3D video surface imaging and video goggles. Five left-breast-cancer patients and fifteen healthy volunteers were asked to perform a series of DIBHs without and with visual coaching. Reproducibility and stability of DIBH were measured for each individual with and without visual coaching. The average reproducibility and stability changed from 2.1 mm and 1.5 mm, respectively, without visual feedback to 0.5 mm and 0.7 mm with visual feedback, showing a significant statistical difference (p 2 mm) in reproducibility and stability were observed in 35% and 15% of the subjects, respectively. The average chest wall excursion of the DIBH with respect to the free breathing preceding the DIBH was found to be 11.3 mm. The reproducibility and stability of the DIBH improve significantly from the visual coaching provided to the patient, especially in those patients with poor reproducibility and stability.

  4. The Influence of Visual and Auditory Information on the Perception of Speech and Non-Speech Oral Movements in Patients with Left Hemisphere Lesions (United States)

    Schmid, Gabriele; Thielmann, Anke; Ziegler, Wolfram


    Patients with lesions of the left hemisphere often suffer from oral-facial apraxia, apraxia of speech, and aphasia. In these patients, visual features often play a critical role in speech and language therapy, when pictured lip shapes or the therapist's visible mouth movements are used to facilitate speech production and articulation. This demands…

  5. Visual Scanning Training, Limb Activation Treatment, and Prism Adaptation for rehabilitating left neglect: Who is the winner?

    Directory of Open Access Journals (Sweden)

    Konstantinos ePriftis


    Full Text Available We compared, for the first time, the overall and differential effects of three of the most widely used left neglect (LN treatments: Visual Scanning Training (VST, Limb Activation Treatment (LAT, and Prism Adaptation (PA. Thirty-three LN patients were assigned in quasi-random order to the three groups (VST, LAT, or PA. Each patient received only one type of treatment. LN patients’ performance on everyday life tasks was assessed four times (over a period of six weeks: A1 and A2 (i.e., the two pre-treatment assessments; A3 and A4 (i.e., the two post-treatment assessments. LN patients in each of the three treatment conditions were treated for the same number of sessions (i.e., 20. The results showed that improvements were present in the majority of the tests assessing the peripersonal space in everyday life activities. Our findings were independent of unspecific factors and lasted for at least two weeks following the end of the treatments. There were no interactions, however, between LN treatments and assessments. We suggest that all three treatments can be considered as valid rehabilitation interventions for LN and could be employed for ameliorating LN signs.

  6. Activation and Functional Connectivity of the Left Inferior Temporal Gyrus during Visual Speech Priming in Healthy Listeners and Listeners with Schizophrenia. (United States)

    Wu, Chao; Zheng, Yingjun; Li, Juanhua; Zhang, Bei; Li, Ruikeng; Wu, Haibo; She, Shenglin; Liu, Sha; Peng, Hongjun; Ning, Yuping; Li, Liang


    Under a "cocktail-party" listening condition with multiple-people talking, compared to healthy people, people with schizophrenia benefit less from the use of visual-speech (lipreading) priming (VSP) cues to improve speech recognition. The neural mechanisms underlying the unmasking effect of VSP remain unknown. This study investigated the brain substrates underlying the unmasking effect of VSP in healthy listeners and the schizophrenia-induced changes in the brain substrates. Using functional magnetic resonance imaging, brain activation and functional connectivity for the contrasts of the VSP listening condition vs. the visual non-speech priming (VNSP) condition were examined in 16 healthy listeners (27.4 ± 8.6 years old, 9 females and 7 males) and 22 listeners with schizophrenia (29.0 ± 8.1 years old, 8 females and 14 males). The results showed that in healthy listeners, but not listeners with schizophrenia, the VSP-induced activation (against the VNSP condition) of the left posterior inferior temporal gyrus (pITG) was significantly correlated with the VSP-induced improvement in target-speech recognition against speech masking. Compared to healthy listeners, listeners with schizophrenia showed significantly lower VSP-induced activation of the left pITG and reduced functional connectivity of the left pITG with the bilateral Rolandic operculum, bilateral STG, and left insular. Thus, the left pITG and its functional connectivity may be the brain substrates related to the unmasking effect of VSP, assumedly through enhancing both the processing of target visual-speech signals and the inhibition of masking-speech signals. In people with schizophrenia, the reduced unmasking effect of VSP on speech recognition may be associated with a schizophrenia-related reduction of VSP-induced activation and functional connectivity of the left pITG.

  7. Left-right asymmetries of behaviour and nervous system in invertebrates. (United States)

    Frasnelli, Elisa; Vallortigara, Giorgio; Rogers, Lesley J


    Evidence of left-right asymmetries in invertebrates has begun to emerge, suggesting that lateralization of the nervous system may be a feature of simpler brains as well as more complex ones. A variety of studies have revealed sensory and motor asymmetries in behaviour, as well as asymmetries in the nervous system, in invertebrates. Asymmetries in behaviour are apparent in olfaction (antennal asymmetries) and in vision (preferential use of the left or right visual hemifield during activities such as foraging or escape from predators) in animals as different as bees, fruitflies, cockroaches, octopuses, locusts, ants, spiders, crabs, snails, water bugs and cuttlefish. Asymmetries of the nervous system include lateralized position of specific brain structures (e.g., in fruitflies and snails) and of specific neurons (e.g., in nematodes). As in vertebrates, lateralization can occur both at the individual and at the population-level in invertebrates. Theoretical models have been developed supporting the hypothesis that the alignment of the direction of behavioural and brain asymmetries at the population-level could have arisen as a result of social selective pressures, when individually asymmetrical organisms had to coordinate with each other. The evidence reviewed suggests that lateralization at the population-level may be more likely to occur in social species among invertebrates, as well as vertebrates. Copyright © 2012 Elsevier Ltd. All rights reserved.

  8. Left-hand somatosensory stimulation combined with visual scanning training in rehabilitation for post-stroke hemineglect: a randomised, double-blind study. (United States)

    Polanowska, Katarzyna; Seniów, Joanna; Paprot, Ewa; Leśniak, Marcin; Członkowska, Anna


    The aim of this randomised, double-blind study was to investigate the therapeutic effectiveness of left-hand electrical stimulation for patients with post-stroke left visuo-spatial neglect. This approach was hypothesised to enhance activation of the right hemisphere attention system and to improve visual exploration of extrapersonal space. Participants (n = 40) in the study were in a relatively early stage of recovery from their first right hemisphere stroke, and were randomly assigned to the experimental (E) or control (C) group. Group E received conventional visual scanning training combined with electrostimulation of the left hand, while Group C received scanning training with sham stimulation. Their visuo-spatial neglect was assessed twice, prior to the rehabilitation programme and on its completion, using cancellation tests and a letter-reading task. The effect of electrostimulation on hemineglect was assessed following a single administration and after a month-long rehabilitation programme. Although the immediate effect of stimulation was poor, after a month-long rehabilitation period we found significantly greater improvement in Group E patients than in Group C patients. Interestingly, the presence of hemisensory loss did not weaken the observed effect. Therefore, we claim that contralesional hand stimulation combined with visual scanning was a more effective treatment for hemineglect rehabilitation than scanning training alone.

  9. Top-down and bottom-up influences on the left ventral occipito-temporal cortex during visual word recognition: an analysis of effective connectivity. (United States)

    Schurz, Matthias; Kronbichler, Martin; Crone, Julia; Richlan, Fabio; Klackl, Johannes; Wimmer, Heinz


    The functional role of the left ventral occipito-temporal cortex (vOT) in visual word processing has been studied extensively. A prominent observation is higher activation for unfamiliar but pronounceable letter strings compared to regular words in this region. Some functional accounts have interpreted this finding as driven by top-down influences (e.g., Dehaene and Cohen [2011]: Trends Cogn Sci 15:254-262; Price and Devlin [2011]: Trends Cogn Sci 15:246-253), while others have suggested a difference in bottom-up processing (e.g., Glezer et al. [2009]: Neuron 62:199-204; Kronbichler et al. [2007]: J Cogn Neurosci 19:1584-1594). We used dynamic causal modeling for fMRI data to test bottom-up and top-down influences on the left vOT during visual processing of regular words and unfamiliar letter strings. Regular words (e.g., taxi) and unfamiliar letter strings of pseudohomophones (e.g., taksi) were presented in the context of a phonological lexical decision task (i.e., "Does the item sound like a word?"). We found no differences in top-down signaling, but a strong increase in bottom-up signaling from the occipital cortex to the left vOT for pseudohomophones compared to words. This finding can be linked to functional accounts which assume that the left vOT contains neurons tuned to complex orthographic features such as morphemes or words [e.g., Dehaene and Cohen [2011]: Trends Cogn Sci 15:254-262; Kronbichler et al. [2007]: J Cogn Neurosci 19:1584-1594]: For words, bottom-up signals converge onto a matching orthographic representation in the left vOT. For pseudohomophones, the propagated signals do not converge, but (partially) activate multiple orthographic word representations, reflected in increased effective connectivity. Copyright © 2013 Wiley Periodicals, Inc.

  10. At-home tDCS of the left dorsolateral prefrontal cortex improves visual short-term memory in mild vascular dementia. (United States)

    André, Sebastian; Heinrich, Simon; Kayser, Friederike; Menzler, Katja; Kesselring, Jürg; Khader, Patrick H; Lefaucheur, Jean-Pascal; Mylius, Veit


    Previous studies have shown that anodal transcranial direct current stimulation (tDCS) of the left dorsolateral prefrontal cortex (DLPFC) led to an improvement of various cognitive functions in patients with Alzheimer dementia, early affected by short-term memory deficits. Since this approach has not been evaluated in the context of vascular dementia, which rather affects the velocity of cognitive responses, we aimed at improving these functions by applying repetitive sessions of anodal tDCS. Four 20-minute sessions of 2mA anodal or sham at-home tDCS were applied to the left DLPFC in a single-blinded randomised study of 21 patients with mild vascular dementia, with parallel-group design. The effect of tDCS on cognitive testing was assessed up to two weeks beyond the stimulation time. A similar clinically meaningful improvement of various cognitive and behavioral dysfunction characteristics could be observed following either active or sham tDCS, whereas visual recall, and reaction times in the n-back task as well as in the go/no-go test improved only in the active tDCS group. In patients with mild vascular dementia, anodal tDCS of the left DLPFC is able to produce additional effects to cognitive training on visual short-term memory, verbal working memory, and executive control. Copyright © 2016 Elsevier B.V. All rights reserved.

  11. The left intraparietal sulcus adapts to symbolic number in both the visual and auditory modalities: Evidence from fMRI. (United States)

    Vogel, Stephan E; Goffin, Celia; Bohnenberger, Joshua; Koschutnig, Karl; Reishofer, Gernot; Grabner, Roland H; Ansari, Daniel


    A growing body of evidence from functional Magnetic Resonance Imaging adaptation (fMRIa) has implicated the left intraparietal sulcus (IPS) as a crucial brain region representing the semantic of number symbols. However, it is currently unknown to what extent the left IPS brain activity can be generalized across modalities (e.g., Arabic digits and spoken number words) and how robust and reproducible numerical adaptation effects are. In two separate fMRIa experiments we habituated the brain response of 20 native English-speaking (Experiment 1) and 34 native German-speaking (Experiment 2) adults to Arabic digits or spoken number words. Consistent with previous findings, experiment 1 revealed numerical ratio dependent adaptation to Arabic numerals in the left IPS using both conventional and cortex-based alignment techniques. Experiment 2 revealed numerical ratio dependent signal recovery in the left IPS following adaptation to both Arabic numerals and spoken number words using both conventional and cortex-based alignment techniques. Together, these findings suggest that the left IPS is involved in symbolic number processing across modalities. Copyright © 2017 Elsevier Inc. All rights reserved.

  12. No deficiency in left-to-right processing of words in dyslexia but evidence for enhanced visual crowding

    NARCIS (Netherlands)

    Callens, Maaike; Whitney, Carol; Tops, Wim; Brysbaert, Marc


    Whitney and Cornelissen hypothesized that dyslexia may be the result of problems with the left-to-right processing of words, particularly in the part of the word between the word beginning and the reader's fixation position. To test this hypothesis, we tachistoscopically presented consonant trigrams

  13. Visual search for item- and array-centred locations in patients with left middle cerebral artery stroke

    NARCIS (Netherlands)

    Hildebrandt, H.; Schütze, C.; Ebke, M.; Eling, P.A.T.M.


    In this study we systematically explored the impact of left hemisphere lesions on array-centred and item-centred spatial attention. We investigated 16 LH first ever stroke patients, focusing on strokes of the Middle Cerebral Artery (MCA), and 15 healthy control subjects with a parallel and serial

  14. Can positions in the visual field with high attentional capabilities be good candidates for a new preferred retinal locus? (United States)

    Barraza-Bernal, Maria J; Ivanov, Iliya V; Nill, Svenja; Rifai, Katharina; Trauzettel-Klosinski, Susanne; Wahl, Siegfried


    The sustained component of visual attention lowers the perceptual threshold of stimuli located at the attended region. Attentional performance is not equal for all eccentric positions, leading to variations in perception. The location of the preferred retinal locus (PRL) for fixation might be influenced by these attentional variations. This study investigated the relation between the placement of sustained attention and the location of a developed PRL using simulations of central scotoma. Thirteen normally sighted subjects participated in the study. Monocular sustained attention was measured in discrete eccentric locations of the visual field using the dominant eye. Subsequently, a six degrees macular scotoma was simulated and PRL training was performed during eight ten-minutes blocks of trials. After training, every subject developed a PRL. Subjects with high attentional capabilities in the lower hemifield generally developed PRLs in the lower hemifield (n=10), subjects with high attentional capabilities in the upper hemifield developed PRLs in the upper hemifield (n=2) and one subject with similar attentional capabilities in the upper and lower hemifield developed the PRL on the upper hemifield. Analyzed individually, the results showed that 70% of the subjects had a PRL location in the hemifield where high attentional performance was achieved. These results suggest that attentional capabilities can be used as a predictor for the development of the PRL and are of significance for low vision rehabilitation and for the development of new PRL training procedures, with the option for a preventive attentional training in early macular disease to develop a favorable PRL. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

  15. Effects of Unilateral Transcranial Direct Current Stimulation of Left Prefrontal Cortex on Processing and Memory of Emotional Visual Stimuli. (United States)

    Balzarotti, Stefania; Colombo, Barbara


    The dorsolateral prefrontal cortex (DLPFC) is generally thought to be involved in affect and emotional processing; however, the specific contribution of each hemisphere continues to be debated. In the present study, we employed unilateral tDCS to test the unique contribution of left DLPFC in the encoding and retrieval of emotional stimuli in healthy subjects. Forty-two right handed undergraduate students received either anodal, cathodal or sham stimulation of left DLPFC while viewing neutral, pleasant, and unpleasant pictures. After completing a filler task, participants were asked to remember as many pictures as possible. Results showed that participants were able to remember a larger amount of emotional (both pleasant and unpleasant) pictures than of neutral ones, regardless of the type of tDCS condition. Participants who received anodal stimulation recalled a significantly higher number of pleasant images than participants in the sham and cathodal conditions, while no differences emerged in the recall of neutral and unpleasant pictures. We conclude that our results provide some support to the role of left prefrontal cortex in the encoding and retrieval of pleasant stimuli.

  16. Effects of Unilateral Transcranial Direct Current Stimulation of Left Prefrontal Cortex on Processing and Memory of Emotional Visual Stimuli.

    Directory of Open Access Journals (Sweden)

    Stefania Balzarotti

    Full Text Available The dorsolateral prefrontal cortex (DLPFC is generally thought to be involved in affect and emotional processing; however, the specific contribution of each hemisphere continues to be debated. In the present study, we employed unilateral tDCS to test the unique contribution of left DLPFC in the encoding and retrieval of emotional stimuli in healthy subjects. Forty-two right handed undergraduate students received either anodal, cathodal or sham stimulation of left DLPFC while viewing neutral, pleasant, and unpleasant pictures. After completing a filler task, participants were asked to remember as many pictures as possible. Results showed that participants were able to remember a larger amount of emotional (both pleasant and unpleasant pictures than of neutral ones, regardless of the type of tDCS condition. Participants who received anodal stimulation recalled a significantly higher number of pleasant images than participants in the sham and cathodal conditions, while no differences emerged in the recall of neutral and unpleasant pictures. We conclude that our results provide some support to the role of left prefrontal cortex in the encoding and retrieval of pleasant stimuli.

  17. Interhemispheric differences of fMRI responses to visual stimuli in patients with side-fixed migraine aura

    DEFF Research Database (Denmark)

    Hougaard, Anders; Amin, Faisal Mohammad; Hoffmann, Michael B


    Migraine sufferers with aura often report photosensitivity and visual discomfort outside of attacks and many consider bright or flickering light an attack-precipitating factor. The nature of this visual hypersensitivity and its relation to the underlying pathophysiology of the migraine aura...... is unknown. Using fMRI measurements during visual stimulation we examined the visual cortical responsiveness of patients with migraine with aura. We applied a within-patient design by assessing functional interhemispheric differences in patients consistently experiencing visual aura in the same visual...... hemifield. We recruited 20 patients with frequent side-fixed visual aura attacks (≥90% of auras occurring in the same visual hemifield) and 20 age and sex matched healthy controls and compared the fMRI blood oxygenation level dependent (BOLD) responses to visual stimulation between symptomatic...

  18. Keeping in Touch With the Visual System: Spatial Alignment and Multisensory Integration of Visual-Somatosensory Inputs

    Directory of Open Access Journals (Sweden)

    Jeannette Rose Mahoney


    Full Text Available Correlated sensory inputs coursing along the individual sensory processing hierarchies arrive at multisensory convergence zones in cortex where inputs are processed in an integrative manner. The exact hierarchical level of multisensory convergence zones and the timing of their inputs are still under debate, although increasingly, evidence points to multisensory integration at very early sensory processing levels. The objective of the current study was to determine, both psychophysically and electrophysiologically, whether differential visual-somatosensory integration patterns exist for stimuli presented to the same versus opposite hemifields. Using high-density electrical mapping and complementary psychophysical data, we examined multisensory integrative processing for combinations of visual and somatosensory inputs presented to both left and right spatial locations. We assessed how early during sensory processing visual-somatosensory (VS interactions were seen in the event-related potential and whether spatial alignment of the visual and somatosensory elements resulted in differential integration effects. Reaction times to all VS pairings were significantly faster than those to the unisensory conditions, regardless of spatial alignment, pointing to engagement of integrative multisensory processing in all conditions. In support, electrophysiological results revealed significant differences between multisensory simultaneous VS and summed V+S responses, regardless of the spatial alignment of the constituent inputs. Nonetheless, multisensory effects were earlier in the aligned conditions, and were found to be particularly robust in the case of right-sided inputs (beginning at just 55ms. In contrast to previous work on audio-visual and audio-somatosensory inputs, the current work suggests a degree of spatial specificity to the earliest detectable multisensory integrative effects in response to visual-somatosensory pairings.

  19. The upper-hemifield advantage for masked face processing: Not just an attentional bias. (United States)

    Quek, Genevieve L; Finkbeiner, Matthew


    Recent evidence suggests that face processing may be more robust in the upper visual field (UVF) than in the lower visual field (LVF). We asked whether this UVF advantage is due to an upward bias in participants' visuospatial attention. Participants classified the sex of a UVF or LVF target face that was preceded by a congruent or incongruent masked prime face. We manipulated spatial attention within subjects by varying the predictability of target location across sessions (UVF:LVF ratio of 50:50 on Day 1 and 20:80 on Day 2). When target location was unpredictable, priming emerged earlier in the UVF (~165 ms) than the LVF (~195 ms). This UVF advantage was reversed when targets were more likely to be presented in the LVF. Here priming arose earlier for LVF targets (~53 ms) than UVF targets (~165 ms). Critically, however, UVF primes were processed to the same degree regardless of whether spatial attention was diffuse (Day 1) or deployed elsewhere (Day 2). We conclude that, while voluntarily directed spatial attention is sufficient to modulate the processing of masked faces in the LVF, it is not sufficient to explain the UVF advantage for masked face processing.

  20. Interaction of a Transapical Miniaturized Ventricular Assist Device With the Left Ventricle: Hemodynamic Evaluation and Visualization in an Isolated Heart Setup. (United States)

    Granegger, Marcus; Aigner, Philipp; Haberl, Thomas; Mahr, Stephane; Tamez, Daniel A; Graham, Joel; Nunez, Nathalie J; Schima, Heinrich; Moscato, Francesco


    New left ventricular assist devices (LVADs) offer both important advantages and potential hazards. VAD development requires better and expeditious ways to identify these advantages and hazards. We validated in an isolated working heart the hemodynamic performance of an intraventricular LVAD and investigated how its outflow cannula interacted with the aortic valve. Hearts from six pigs were explanted and connected to an isolated working heart setup. A miniaturized LVAD was implanted within the left ventricle (tMVAD, HeartWare Inc., Miami Lakes, FL, USA). In four experiments blood was used to investigate hemodynamics under various loading conditions. In two experiments crystalloid perfusate was used, allowing visualization of the outflow cannula within the aortic valve. In all hearts the transapical miniaturized ventricular assist device (tMVAD) implantation was successful. In the blood experiments hemodynamics similar to those observed clinically were achieved. Pump speeds ranged from 9 to 22 krpm with a maximum of 7.6 L/min against a pressure difference between ventricle and aorta of ∼50 mm Hg. With crystalloid perfusate, central positioning of the outflow cannula in the aortic root was observed during full and partial support. With decreasing aortic pressures the cannula tended to drift toward the aortic root wall. The tMVAD could unload the ventricle similarly to LVADs under conventional cannulation. Aortic pressure influenced central positioning of the outflow cannula in the aortic root. The isolated heart is a simple, accessible evaluation platform unaffected by complex reactions within a whole, living animal. This platform allowed detection and visualization of potential hazards. Copyright © 2016 International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.

  1. Interlateral Asymmetry in the Time Course of the Effect of a Peripheral Prime Stimulus (United States)

    Castro-Barros, B. A.; Righi, L. L.; Grechi, G.; Ribeiro-do-Valle, L. E.


    Evidence exists that both right and left hemisphere attentional mechanisms are mobilized when attention is directed to the right visual hemifield and only right hemisphere attentional mechanisms are mobilized when attention is directed to the left visual hemifield. This arrangement might lead to a rightward bias of automatic attention. The…

  2. Functional magnetic resonance imaging of the human primary visual cortex during visual stimulation

    International Nuclear Information System (INIS)

    Miki, Atsushi; Abe, Haruki; Nakajima, Takashi; Fujita, Motoi; Watanabe, Hiroyuki; Kuwabara, Takeo; Naruse, Shoji; Takagi, Mineo.


    Signal changes in the human primary visual cortex during visual stimulation were evaluated using non-invasive functional magnetic resonance imaging (fMRI). The experiments were performed on 10 normal human volunteers and 2 patients with homonymous hemianopsia, including one who was recovering from the exacerbation of multiple sclerosis. The visual stimuli were provided by a pattern generator using the checkerboard pattern for determining the visual evoked potential of full-field and hemifield stimulation. In normal volunteers, a signal increase was observed on the bilateral primary visual cortex during the full-field stimulation and on the contra-lateral cortex during hemifield stimulation. In the patient with homonymous hemianopsia after cerebral infarction, the signal change was clearly decreased on the affected side. In the other patient, the one recovering from multiple sclerosis with an almost normal visual field, the fMRI was within normal limits. These results suggest that it is possible to visualize the activation of the visual cortex during visual stimulation, and that there is a possibility of using this test as an objective method of visual field examination. (author)

  3. Contralateral Cortical Organisation of Information in Visual Short-Term Memory: Evidence from Lateralized Brain Activity during Retrieval (United States)

    Fortier-Gauthier, Ulysse; Moffat, Nicolas; Dell'Acqua, Robert; McDonald, John J.; Jolicoeur, Pierre


    We studied brain activity during retention and retrieval phases of two visual short-term memory (VSTM) experiments. Experiment 1 used a balanced memory array, with one color stimulus in each hemifield, followed by a retention interval and a central probe, at the fixation point that designated the target stimulus in memory about which to make a…

  4. Visual Working Memory Load-Related Changes in Neural Activity and Functional Connectivity (United States)

    Li, Ling; Zhang, Jin-Xiang; Jiang, Tao


    Background Visual working memory (VWM) helps us store visual information to prepare for subsequent behavior. The neuronal mechanisms for sustaining coherent visual information and the mechanisms for limited VWM capacity have remained uncharacterized. Although numerous studies have utilized behavioral accuracy, neural activity, and connectivity to explore the mechanism of VWM retention, little is known about the load-related changes in functional connectivity for hemi-field VWM retention. Methodology/Principal Findings In this study, we recorded electroencephalography (EEG) from 14 normal young adults while they performed a bilateral visual field memory task. Subjects had more rapid and accurate responses to the left visual field (LVF) memory condition. The difference in mean amplitude between the ipsilateral and contralateral event-related potential (ERP) at parietal-occipital electrodes in retention interval period was obtained with six different memory loads. Functional connectivity between 128 scalp regions was measured by EEG phase synchronization in the theta- (4–8 Hz), alpha- (8–12 Hz), beta- (12–32 Hz), and gamma- (32–40 Hz) frequency bands. The resulting matrices were converted to graphs, and mean degree, clustering coefficient and shortest path length was computed as a function of memory load. The results showed that brain networks of theta-, alpha-, beta-, and gamma- frequency bands were load-dependent and visual-field dependent. The networks of theta- and alpha- bands phase synchrony were most predominant in retention period for right visual field (RVF) WM than for LVF WM. Furthermore, only for RVF memory condition, brain network density of theta-band during the retention interval were linked to the delay of behavior reaction time, and the topological property of alpha-band network was negative correlation with behavior accuracy. Conclusions/Significance We suggest that the differences in theta- and alpha- bands between LVF and RVF conditions in

  5. Keeping in touch with the visual system: spatial alignment and multisensory integration of visual-somatosensory inputs. (United States)

    Mahoney, Jeannette R; Molholm, Sophie; Butler, John S; Sehatpour, Pejman; Gomez-Ramirez, Manuel; Ritter, Walter; Foxe, John J


    Correlated sensory inputs coursing along the individual sensory processing hierarchies arrive at multisensory convergence zones in cortex where inputs are processed in an integrative manner. The exact hierarchical level of multisensory convergence zones and the timing of their inputs are still under debate, although increasingly, evidence points to multisensory integration (MSI) at very early sensory processing levels. While MSI is said to be governed by stimulus properties including space, time, and magnitude, violations of these rules have been documented. The objective of the current study was to determine, both psychophysically and electrophysiologically, whether differential visual-somatosensory (VS) integration patterns exist for stimuli presented to the same versus opposite hemifields. Using high-density electrical mapping and complementary psychophysical data, we examined multisensory integrative processing for combinations of visual and somatosensory inputs presented to both left and right spatial locations. We assessed how early during sensory processing VS interactions were seen in the event-related potential and whether spatial alignment of the visual and somatosensory elements resulted in differential integration effects. Reaction times to all VS pairings were significantly faster than those to the unisensory conditions, regardless of spatial alignment, pointing to engagement of integrative multisensory processing in all conditions. In support, electrophysiological results revealed significant differences between multisensory simultaneous VS and summed V + S responses, regardless of the spatial alignment of the constituent inputs. Nonetheless, multisensory effects were earlier in the aligned conditions, and were found to be particularly robust in the case of right-sided inputs (beginning at just 55 ms). In contrast to previous work on audio-visual and audio-somatosensory inputs, the current work suggests a degree of spatial specificity to the earliest

  6. Efficient visual object and word recognition relies on high spatial frequency coding in the left posterior fusiform gyrus: evidence from a case-series of patients with ventral occipito-temporal cortex damage. (United States)

    Roberts, Daniel J; Woollams, Anna M; Kim, Esther; Beeson, Pelagie M; Rapcsak, Steven Z; Lambon Ralph, Matthew A


    Recent visual neuroscience investigations suggest that ventral occipito-temporal cortex is retinotopically organized, with high acuity foveal input projecting primarily to the posterior fusiform gyrus (pFG), making this region crucial for coding high spatial frequency information. Because high spatial frequencies are critical for fine-grained visual discrimination, we hypothesized that damage to the left pFG should have an adverse effect not only on efficient reading, as observed in pure alexia, but also on the processing of complex non-orthographic visual stimuli. Consistent with this hypothesis, we obtained evidence that a large case series (n = 20) of patients with lesions centered on left pFG: 1) Exhibited reduced sensitivity to high spatial frequencies; 2) demonstrated prolonged response latencies both in reading (pure alexia) and object naming; and 3) were especially sensitive to visual complexity and similarity when discriminating between novel visual patterns. These results suggest that the patients' dual reading and non-orthographic recognition impairments have a common underlying mechanism and reflect the loss of high spatial frequency visual information normally coded in the left pFG.

  7. Heatline visualization of natural convection heat transfer in an inclined wavy cavities filled with nanofluids and subjected to a discrete isoflux heating from its left sidewall

    Directory of Open Access Journals (Sweden)

    Ahmed Kadhim Hussein


    Full Text Available Natural convection visualization by heatlines in three types of inclined wavy cavities filled with Al2O3–water and Ag–water nanofluids and subjected to a discrete isoflux heating from its left sidewall is investigated numerically in this work. The right sidewall together with remaining regions in the left sidewall is insulated. The solution is based on the finite volume method. The upper and lower cavity walls are maintained at a constant cold temperature and follow a profile of sine wave. Numerical computations are carried out for various values of the solid volume fraction [φ = 0, 0.05, 0.1, 0.15 and 0.2], number of undulations [N = 1, 2 and 3], Rayleigh number [Ra = 103–107], the ratio of heating element length to the cavity height [ε = 0.2, 0.4, 0.6, 0.8 and 1.0], the cavity inclination angle [Φ = 0°, 30°, 60° and 90°] and the wave amplitude [γ = 0.1, 0.15 and 0.2]. The results are presented in terms of heatlines, isotherms, streamlines together with local and average Nusselt numbers. It is found that the geometry of the wavy cavity has a cursive role on the flow and thermal fields pattern. The results also explained that streamlines and isotherms were affected significantly for high Rayleigh number and vertical cavity position [Φ = 90°]. Also, when the solid volume fractions and wave amplitudes increase, the local Nusselt number along the heat source increases. Furthermore, velocity profiles increase as [ε] increases near the left sidewall of the cavity while they decrease as [ε] increases near the right sidewall of the cavity. For all three types of horizontal wavy cavities the heat functions increase for both nano and base fluids when the wave amplitude increases. Finally, results of the present work indicated that both heatlines and heat functions techniques are applied efficiently to describe the natural convection heat transfer inside wavy cavities filled with nanofluid.

  8. Increase in MST activity correlates with visual motion learning: A functional MRI study of perceptual learning. (United States)

    Larcombe, Stephanie J; Kennard, Chris; Bridge, Holly


    Repeated practice of a specific task can improve visual performance, but the neural mechanisms underlying this improvement in performance are not yet well understood. Here we trained healthy participants on a visual motion task daily for 5 days in one visual hemifield. Before and after training, we used functional magnetic resonance imaging (fMRI) to measure the change in neural activity. We also imaged a control group of participants on two occasions who did not receive any task training. While in the MRI scanner, all participants completed the motion task in the trained and untrained visual hemifields separately. Following training, participants improved their ability to discriminate motion direction in the trained hemifield and, to a lesser extent, in the untrained hemifield. The amount of task learning correlated positively with the change in activity in the medial superior temporal (MST) area. MST is the anterior portion of the human motion complex (hMT+). MST changes were localized to the hemisphere contralateral to the region of the visual field, where perceptual training was delivered. Visual areas V2 and V3a showed an increase in activity between the first and second scan in the training group, but this was not correlated with performance. The contralateral anterior hippocampus and bilateral dorsolateral prefrontal cortex (DLPFC) and frontal pole showed changes in neural activity that also correlated with the amount of task learning. These findings emphasize the importance of MST in perceptual learning of a visual motion task. Hum Brain Mapp 39:145-156, 2018. © 2017 Wiley Periodicals, Inc. © 2017 The Authors Human Brain Mapping Published by Wiley Periodicals, Inc.

  9. Asymmetrical interhemispheric connections develop in cat visual cortex after early unilateral convergent strabismus: Anatomy, physiology and mechanisms

    Directory of Open Access Journals (Sweden)

    Emmanuel eBui Quoc


    Full Text Available In the mammalian primary visual cortex, the corpus callosum contributes to the unification of the visual hemifields that project to the two hemispheres. Its development depends on visual experience. When the latter is abnormal, callosal connections must undergo dramatic anatomical and physiological changes. However, such data are sparse and incomplete. Thus, little is known about the consequences of abnormal postnatal visual experience on the development of callosal connections and their role in unifying representation of the two hemifields. Here, the effects of early unilateral convergent strabismus (a model of abnormal visual experience were fully characterized with respect to the development of the callosal connections in cat visual cortex, an experimental model for humans. Electrophysiological responses and 3D reconstruction of single callosal axons show that abnormally asymmetrical callosal connections develop after unilateral convergent strabismus, resulting from an extension of axonal branches of specific orders in the hemisphere ipsilateral to the deviated eye and a decreased number of nodes and terminals in the other (ipsilateral to the non deviated eye. Furthermore this asymmetrical organization prevents the establishment of a unifying representation of the two visual hemifields. As a general rule, we suggest that crossed and uncrossed retino-geniculo-cortical pathways contribute in succession to the development of the callosal maps in visual cortex.

  10. SU-E-J-62: Breath Hold for Left-Sided Breast Cancer: Visually Monitored Deep Inspiration Breath Hold Amplitude Evaluated Using Real-Time Position Management

    International Nuclear Information System (INIS)

    Conroy, L; Quirk, S; Smith, WL; Yeung, R; Phan, T; Hudson, A


    Purpose: We used Real-Time Position Management (RPM) to evaluate breath hold amplitude and variability when gating with a visually monitored deep inspiration breath hold technique (VM-DIBH) with retrospective cine image chest wall position verification. Methods: Ten patients with left-sided breast cancer were treated using VM-DIBH. Respiratory motion was passively collected once weekly using RPM with the marker block positioned at the xiphoid process. Cine images on the tangent medial field were acquired on fractions with RPM monitoring for retrospective verification of chest wall position during breath hold. The amplitude and duration of all breath holds on which treatment beams were delivered were extracted from the RPM traces. Breath hold position coverage was evaluated for symmetric RPM gating windows from ± 1 to 5 mm centered on the average breath hold amplitude of the first measured fraction as a baseline. Results: The average (range) breath hold amplitude and duration was 18 mm (3–36 mm) and 19 s (7–34 s). The average (range) of amplitude standard deviation per patient over all breath holds was 2.7 mm (1.2–5.7 mm). With the largest allowable RPM gating window (± 5 mm), 4 of 10 VM-DIBH patients would have had ≥ 10% of their breath hold positions excluded by RPM. Cine verification of the chest wall position during the medial tangent field showed that the chest wall was greater than 5 mm from the baseline in only 1 out of 4 excluded patients. Cine images verify the chest wall/breast position only, whether this variation is acceptable in terms of heart sparing is a subject of future investigation. Conclusion: VM-DIBH allows for greater breath hold amplitude variability than using a 5 mm gating window with RPM, while maintaining chest wall positioning accuracy within 5 mm for the majority of patients

  11. Left Gastric Vein Visualization with Hepatopetal Flow Information in Healthy Subjects Using Non-Contrast-Enhanced Magnetic Resonance Angiography with Balanced Steady-State Free-Precession Sequence and Time-Spatial Labeling Inversion Pulse. (United States)

    Furuta, Akihiro; Isoda, Hiroyoshi; Ohno, Tsuyoshi; Ono, Ayako; Yamashita, Rikiya; Arizono, Shigeki; Kido, Aki; Sakashita, Naotaka; Togashi, Kaori


    To selectively visualize the left gastric vein (LGV) with hepatopetal flow information by non-contrast-enhanced magnetic resonance angiography under a hypothesis that change in the LGV flow direction can predict the development of esophageal varices; and to optimize the acquisition protocol in healthy subjects. Respiratory-gated three-dimensional balanced steady-state free-precession scans were conducted on 31 healthy subjects using two methods (A and B) for visualizing the LGV with hepatopetal flow. In method A, two time-spatial labeling inversion pulses (Time-SLIP) were placed on the whole abdomen and the area from the gastric fornix to the upper body, excluding the LGV area. In method B, nonselective inversion recovery pulse was used and one Time-SLIP was placed on the esophagogastric junction. The detectability and consistency of LGV were evaluated using the two methods and ultrasonography (US). Left gastric veins by method A, B, and US were detected in 30 (97%), 24 (77%), and 23 (74%) subjects, respectively. LGV flow by US was hepatopetal in 22 subjects and stagnant in one subject. All hepatopetal LGVs by US coincided with the visualized vessels in both methods. One subject with non-visualized LGV in method A showed stagnant LGV by US. Hepatopetal LGV could be selectively visualized by method A in healthy subjects.

  12. Visual attention capacity after right hemisphere lesions

    DEFF Research Database (Denmark)

    Habekost, Thomas; Rostrup, Egill


    Recently there has been a growing interest in visual short-term memory (VSTM) including the neural basis of the function. Processing speed, another main aspect of visual attention capacity, has received less investigation. For both cognitive functions human lesion studies are sparse. We used...... a whole report experiment for estimation of these two parameters in 22 patients with right side stroke. Psychophysical performance was analyzed using Bundesen's [Bundesen, C. (1990). A theory of visual attention. Psychological Review, 97, 523-547] Theory of Visual Attention (TVA) and compared...... statistically to lesion location and size measured by MRI. Visual processing speed was impaired in the contralesional hemifield for most patients, but typically preserved ipsilesionally, even after large cortico-subcortical lesions. When bilateral deficits in processing speed occurred, they were related...

  13. From Cortical Blindness to Conscious Visual Perception: Theories on Neuronal Networks and Visual Training Strategies. (United States)

    Hadid, Vanessa; Lepore, Franco


    Homonymous hemianopia (HH) is the most common cortical visual impairment leading to blindness in the contralateral hemifield. It is associated with many inconveniences and daily restrictions such as exploration and visual orientation difficulties. However, patients with HH can preserve the remarkable ability to unconsciously perceive visual stimuli presented in their blindfield, a phenomenon known as blindsight. Unfortunately, the nature of this captivating residual ability is still misunderstood and the rehabilitation strategies in terms of visual training have been insufficiently exploited. This article discusses type I and type II blindsight in a neuronal framework of altered global workspace, resulting from inefficient perception, attention and conscious networks. To enhance synchronization and create global availability for residual abilities to reach visual consciousness, rehabilitation tools need to stimulate subcortical extrastriate pathways through V5/MT. Multisensory bottom-up compensation combined with top-down restitution training could target pre-existing and new neuronal mechanisms to recreate a framework for potential functionality.

  14. Stress Sensitive Healthy Females Show Less Left Amygdala Activation in Response to Withdrawal-Related Visual Stimuli under Passive Viewing Conditions (United States)

    Baeken, Chris; Van Schuerbeek, Peter; De Raedt, Rudi; Vanderhasselt, Marie-Anne; De Mey, Johan; Bossuyt, Axel; Luypaert, Robert


    The amygdalae are key players in the processing of a variety of emotional stimuli. Especially aversive visual stimuli have been reported to attract attention and activate the amygdalae. However, as it has been argued that passively viewing withdrawal-related images could attenuate instead of activate amygdalae neuronal responses, its role under…

  15. Relationship between the Short-Term Visual Memory and IQ in the Right-and Left-Handed Subjects Trained in Different Educational Programs: I-General Assessment (United States)

    Yilmaz, Yavuz; Yetkin, Yalçin


    The relationship between mean intelligence quotient (IQ), hand preferences and visual memory (VM) were investigated on (N = 612) males and females students trained in different educational programs in viewpoint of laterality. IQ was assessed by cattle's culture Fair intelligence test-A (CCFIT-A). The laterality of the one side of the body was…

  16. Comparison of treadmill exercise stress cardiac MRI to stress echocardiography in healthy volunteers for adequacy of left ventricular endocardial wall visualization: A pilot study. (United States)

    Thavendiranathan, Paaladinesh; Dickerson, Jennifer A; Scandling, Debbie; Balasubramanian, Vijay; Pennell, Michael L; Hinton, Alice; Raman, Subha V; Simonetti, Orlando P


    To compare exercise stress cardiac magnetic resonance (cardiac MR) to echocardiography in healthy volunteers with respect to adequacy of endocardial visualization and confidence of stress study interpretation. Twenty-eight healthy volunteers (age 28 ± 11 years, 15 males) underwent exercise stress echo and cardiac MR one week apart assigned randomly to one test first. Stress cardiac MR was performed using an MRI-compatible treadmill; stress echo was performed as per routine protocol. Cardiac MR and echo images were independently reviewed and scored for adequacy of endocardial visualization and confidence in interpretation of the stress study. Heart rate at the time of imaging was similar between the studies. Average time from cessation of exercise to start of imaging (21 vs. 31 s, P Exercise stress cardiac MR to assess peak exercise wall motion is feasible and can be performed at least as rapidly as stress echo. Copyright © 2013 Wiley Periodicals, Inc.

  17. Improved interobserver variability and accuracy of echocardiographic visual left ventricular ejection fraction assessment through a self-directed learning program using cardiac magnetic resonance images. (United States)

    Thavendiranathan, Paaladinesh; Popović, Zoran B; Flamm, Scott D; Dahiya, Arun; Grimm, Richard A; Marwick, Thomas H


    Although not recommended in isolation, visual estimation of echocardiographic ejection fraction (EF) is widely applied to confirm quantitative EF. However, interobserver variability for EF estimation has been reported to be as high as 14%. The aim of this study was to determine whether self-directed education could improve the accuracy and interobserver variability of visual estimation of EF and whether a multireader estimate improves measurement precision. Thirty-one participants provided single-point EF estimates for 30 echocardiograms with a spectrum of EFs, image quality, and clinical contexts in patients undergoing cardiac magnetic resonance (CMR) within 48 hours. Participants received their own case-by-case variance from CMR EF, and the 10 cases with the largest reader variability were discussed along with corresponding CMR images. Self-directed learning was undertaken by side-by-side review of echocardiographic and CMR images. Two months later, 20 new cases were shown to the same 31 participants, using the same methodology. The baseline interobserver variability of ±0.120 improved to ±0.097 after the intervention. EF misclassification (defined as ±0.05 of CMR EF) was reduced from 56% to 47% (P self-directed intervention modestly decreased interobserver variability and improved the accuracy of EF measurements. Combined physician-sonographer EF reporting improved the precision of EF estimates. Copyright © 2013 American Society of Echocardiography. Published by Mosby, Inc. All rights reserved.

  18. Asymmetry and symmetry in brain waves from dolphin left and right hemispheres: some observations after anesthesia, during quiescent hanging behavior, and during visual obstruction. (United States)

    Ridgway, S H


    Studies of sleep in cetaceans (whales, dolphins, and porpoises), substantiated by electrophysiological data, are rare with the great majority of observations having been made by one group from Russia. This group employed hard-wired recording with low-noise cables for their EEG observations, whereas our report describes behavioral and EEG observations of dolphin sleep using telemetry. Marked asymmetry of the EEG was observed during behavioral sleep posture. At different times synchronized slow waves appeared in both left and right brain hemispheres concurrently with lower voltage, faster, desynchronized EEG activity in the opposite hemisphere. On the other hand, during one brief period of sleep behavior, sleep-like EEG activity appeared on leads from both hemispheres. When the animal was exposed to a loud sound, it woke with lower voltage, faster, relatively symmetrical, desynchronized EEG activity appearing from both hemispheres. Additionally, the EEG appeared relatively desynchronized and symmetrical between the two hemispheres when the animal was awake during recovery from pentothal-halothane anesthesia as well as during waking periods when one or both of the animal's eyes were covered by an opaque rubber suction cup. Copyright 2002 S. Karger AG, Basel

  19. Visual cognition

    Energy Technology Data Exchange (ETDEWEB)

    Pinker, S.


    This book consists of essays covering issues in visual cognition presenting experimental techniques from cognitive psychology, methods of modeling cognitive processes on computers from artificial intelligence, and methods of studying brain organization from neuropsychology. Topics considered include: parts of recognition; visual routines; upward direction; mental rotation, and discrimination of left and right turns in maps; individual differences in mental imagery, computational analysis and the neurological basis of mental imagery: componental analysis.



    SriKamkshi Kothandaraman; Balasubramanian Thiagarajan


    Being a left-handed surgeon, more specifically a left-handed ENT surgeon, presents a unique pattern of difficulties.This article is an overview of left-handedness and a personal account of the specific difficulties a left-handed ENT surgeon faces.

  1. A computerised screening for visual field defects in brain injury patients

    DEFF Research Database (Denmark)

    Nordfang, Maria; Uhre, Valdemar H.B.; Robotham, Ro Julia

    parameters like the number of stimulus repetitions, the colour of stimuli and background, and the orientation of the layout can be individually set. The c-VFT probes all four quadrants and probes along the horizontal midline, making it particularly sensitive for visual field deficits that affect reading...... The c-VFT is a computer program written in open source Python using Psychopy and can be installed without a license. The program tests 48 points in the visual field, covering the visual field from 1 degree to 10 degrees in each hemifield. A colour change detection task controls fixation. Several...... Preliminary analyses indicate that the c-VFT is a sensitive screening tool for visual field defects (anopias) that can be used in neuropsychological practice when other measures of visual field defects are lacking. It should, however, not be considered a diagnostic tool. Assessment can be performed quickly...

  2. Interhemispheric integration in visual search. (United States)

    Shipp, Stewart


    The search task of Luck, Hillyard, Mangun and Gazzaniga (1989) was optimised to test for the presence of a bilateral field advantage in the visual search capabilities of normal subjects. The modified design used geometrically regular arrays of 2, 4 or 8 items restricted to hemifields delineated by the vertical or horizontal meridian; the target, if present, appeared at one of two fixed positions per quadrant at an eccentricity of 11 deg. Group and individual performance data were analysed in terms of the slope of response time against display-size functions ('RT slope'). Averaging performance across all conditions save display mode (bilateral vs. unilateral) revealed a significant bilateral advantage in the form of a 21% increase in apparent item scanning speed for target detection; in the absence of a target, bilateral displays gave a 5% increase in speed that was not significant. Factor analysis by ANOVA confirmed this main effect of display mode, and also revealed several higher order interactions with display geometry, indicating that the bilateral advantage was masked at certain target positions by a crowding-like effect. In a numerical model of search efficiency (i.e. RT slope), bilateral advantage was parameterised by an interhemispheric 'transfer factor' (T) that governs the strength of the ipsilateral representation of distractors, and modifies the level of intrahemispheric competition with the target. The factor T was found to be higher in superior field than inferior field; this result held for the modelled data of each individual subject, as well as the group, representing a uniform tendency for the bilateral advantage to be more prominent in inferior field. In fact statistical analysis and modelling of search efficiency showed that the geometrical display factors (target polar and quadrantic location, and associated crowding effects) were all remarkably consistent across subjects. Greater variability was inferred within a fixed, decisional component of

  3. Spatial Location in Brief, Free-Viewing Face Encoding Modulates Contextual Face Recognition

    Directory of Open Access Journals (Sweden)

    Fatima M. Felisberti


    Full Text Available The effect of the spatial location of faces in the visual field during brief, free-viewing encoding in subsequent face recognition is not known. This study addressed this question by tagging three groups of faces with cheating, cooperating or neutral behaviours and presenting them for encoding in two visual hemifields (upper vs. lower or left vs. right. Participants then had to indicate if a centrally presented face had been seen before or not. Head and eye movements were free in all phases. Findings showed that the overall recognition of cooperators was significantly better than cheaters, and it was better for faces encoded in the upper hemifield than in the lower hemifield, both in terms of a higher d' and faster reaction time (RT. The d' for any given behaviour in the left and right hemifields was similar. The RT in the left hemifield did not vary with tagged behaviour, whereas the RT in the right hemifield was longer for cheaters than for cooperators. The results showed that memory biases in contextual face recognition were modulated by the spatial location of briefly encoded faces and are discussed in terms of scanning reading habits, top-left bias in lighting preference and peripersonal space.

  4. Visual working memory gives up attentional control early in learning: ruling out interhemispheric cancellation. (United States)

    Reinhart, Robert M G; Carlisle, Nancy B; Woodman, Geoffrey F


    Current research suggests that we can watch visual working memory surrender the control of attention early in the process of learning to search for a specific object. This inference is based on the observation that the contralateral delay activity (CDA) rapidly decreases in amplitude across trials when subjects search for the same target object. Here, we tested the alternative explanation that the role of visual working memory does not actually decline across learning, but instead lateralized representations accumulate in both hemispheres across trials and wash out the lateralized CDA. We show that the decline in CDA amplitude occurred even when the target objects were consistently lateralized to a single visual hemifield. Our findings demonstrate that reductions in the amplitude of the CDA during learning are not simply due to the dilution of the CDA from interhemispheric cancellation. Copyright © 2014 Society for Psychophysiological Research.

  5. Laterality and performance of agility-trained dogs. (United States)

    Siniscalchi, Marcello; Bertino, Daniele; Quaranta, Angelo


    Correlations between lateralised behaviour and performance were investigated in 19 agility-trained dogs (Canis familiaris) by scoring paw preference to hold a food object and relating it to performance during typical agility obstacles (jump/A-frame and weave poles). In addition, because recent behavioural studies reported that visual stimuli of emotional valence presented to one visual hemifield at a time affect visually guided motor responses in dogs, the possibility that the position of the owner respectively in the left and in the right canine visual hemifield might be associated with quality of performance during agility was considered. Dogs' temperament was also measured by an owner-rated questionnaire. The most relevant finding was that agility-trained dogs displayed longer latencies to complete the obstacles with the owner located in their left visual hemifield compared to the right. Interestingly, the results showed that this phenomenon was significantly linked to both dogs' trainability and the strength of paw preference.

  6. Ipsilesional deficit of selective attention in left homonymous hemianopia and left unilateral spatial neglect. (United States)

    Chokron, Sylvie; Peyrin, Carole; Perez, Céline


    Patients with homonymous hemianopia may present a subtle ipsilesional deficit, recently referred to as 'sightblindness' in addition to the contralesional visual field defect. We recently demonstrated that this deficit could be worse in right brain-damaged patients with left hemianopia than in left brain-damaged patients with right hemianopia, confirming right hemisphere dominance for visuo-spatial and attentional capacities. In the present study we investigate whether this ipsilesional deficit could be attentional in nature and to what extent it is comparable in right brain-damaged (RBD) patients with left hemianopia and in RBD patients with left neglect. The study was also conducted in RBD patients with neither left hemianopia nor left neglect signs in order to test if a right hemisphere lesion per se could be responsible for subtle ipsilesional attentional deficit. To reach this aim, we tested selective attentional capacities in both visual fields of 10 right brain-damaged patients with left neglect (LN), 8 right brain-damaged patients with left homonymous hemianopia (LHH), 8 right brain-damaged patients with no signs of left neglect or left hemianopia (RBD controls), and 17 healthy age-matched participants (Normal controls). A lateralized letter-detection task was used to test if right-brain damaged patients with LN or LH may present a deficit of selective attention in their right, ipsilesional visual field, in comparison to Normal and RBD controls. Participants were asked to detect a target letter in either a single large stimulus (low attentional load) or a small stimulus surrounded by flankers (high attentional load). Stimuli were displayed either in the left or in the right visual field. Accuracy and reaction times were recorded. Results on accuracy showed that both LN and LH patients exhibited lower correct responses than Normal controls in their ipsilesional right visual field, suggesting an attentional deficit in their ipsilesional, supposed healthy

  7. Left atrial volume index

    DEFF Research Database (Denmark)

    Poulsen, Mikael K; Dahl, Jordi S; Henriksen, Jan Erik


    To determine the prognostic importance of left atrial (LA) dilatation in patients with type 2 diabetes (T2DM) and no history of cardiovascular disease.......To determine the prognostic importance of left atrial (LA) dilatation in patients with type 2 diabetes (T2DM) and no history of cardiovascular disease....

  8. Hemispheric asymmetry of emotion words in a non-native mind: a divided visual field study. (United States)

    Jończyk, Rafał


    This study investigates hemispheric specialization for emotional words among proficient non-native speakers of English by means of the divided visual field paradigm. The motivation behind the study is to extend the monolingual hemifield research to the non-native context and see how emotion words are processed in a non-native mind. Sixty eight females participated in the study, all highly proficient in English. The stimuli comprised 12 positive nouns, 12 negative nouns, 12 non-emotional nouns and 36 pseudo-words. To examine the lateralization of emotion, stimuli were presented unilaterally in a random fashion for 180 ms in a go/no-go lexical decision task. The perceptual data showed a right hemispheric advantage for processing speed of negative words and a complementary role of the two hemispheres in the recognition accuracy of experimental stimuli. The data indicate that processing of emotion words in non-native language may require greater interhemispheric communication, but at the same time demonstrates a specific role of the right hemisphere in the processing of negative relative to positive valence. The results of the study are discussed in light of the methodological inconsistencies in the hemifield research as well as the non-native context in which the study was conducted.

  9. Adults with Dyslexia Demonstrate Space-Based and Object-Based Covert Attention Deficits: Shifting Attention to the Periphery and Shifting Attention between Objects in the Left Visual Field (United States)

    Buchholz, J.; Davies, A.A.


    Performance on a covert visual attention task is compared between a group of adults with developmental dyslexia (specifically phonological difficulties) and a group of age and IQ matched controls. The group with dyslexia were generally slower to detect validly-cued targets. Costs of shifting attention toward the periphery when the target was…

  10. Left heart catheterization (United States)

    Catheterization - left heart ... to help guide the catheters up into your heart and arteries. Dye (sometimes called "contrast") will be ... in the blood vessels that lead to your heart. The catheter is then moved through the aortic ...

  11. [Recurrent left atrial myxoma]. (United States)

    Moreno Martínez, Francisco L; Lagomasino Hidalgo, Alvaro; Mirabal Rodríguez, Roger; López Bermúdez, Félix H; López Bernal, Omaida J


    Primary cardiac tumors are rare. Mixomas are the most common among them; 75% are located in the left atrium, 20% in the right atrium, and the rest in the ventricles. The seldom appear in atrio-ventricular valves. Recidivant mixoma are also rare, appearing in 1-5% of all patients that have undergone surgical treatment of a mixoma. In this paper we present our experience with a female patient, who 8 years after having been operated of a left atrial mixoma, began with symptoms of mild heart failure. Transthoracic echocardiography revealed recurrence of the tumor, and was therefore subjected to a second open-heart surgery from which she recovered without complications.

  12. Left atrial appendage occlusion

    Directory of Open Access Journals (Sweden)

    Ahmad Mirdamadi


    Full Text Available Left atrial appendage (LAA occlusion is a treatment strategy to prevent blood clot formation in atrial appendage. Although, LAA occlusion usually was done by catheter-based techniques, especially percutaneous trans-luminal mitral commissurotomy (PTMC, it can be done during closed and open mitral valve commissurotomy (CMVC, OMVC and mitral valve replacement (MVR too. Nowadays, PTMC is performed as an optimal management of severe mitral stenosis (MS and many patients currently are treated by PTMC instead of previous surgical methods. One of the most important contraindications of PTMC is presence of clot in LAA. So, each patient who suffers of severe MS is evaluated by Trans-Esophageal Echocardiogram to rule out thrombus in LAA before PTMC. At open heart surgery, replacement of the mitral valve was performed for 49-year-old woman. Also, left atrial appendage occlusion was done during surgery. Immediately after surgery, echocardiography demonstrates an echo imitated the presence of a thrombus in left atrial appendage area, although there was not any evidence of thrombus in pre-pump TEE. We can conclude from this case report that when we suspect of thrombus of left atrial, we should obtain exact history of previous surgery of mitral valve to avoid misdiagnosis clotted LAA, instead of obliterated LAA. Consequently, it can prevent additional evaluations and treatments such as oral anticoagulation and exclusion or postponing surgeries including PTMC.

  13. Hypoplastic left heart syndrome

    Directory of Open Access Journals (Sweden)

    Thiagarajan Ravi


    Full Text Available Abstract Hypoplastic left heart syndrome(HLHS refers to the abnormal development of the left-sided cardiac structures, resulting in obstruction to blood flow from the left ventricular outflow tract. In addition, the syndrome includes underdevelopment of the left ventricle, aorta, and aortic arch, as well as mitral atresia or stenosis. HLHS has been reported to occur in approximately 0.016 to 0.036% of all live births. Newborn infants with the condition generally are born at full term and initially appear healthy. As the arterial duct closes, the systemic perfusion becomes decreased, resulting in hypoxemia, acidosis, and shock. Usually, no heart murmur, or a non-specific heart murmur, may be detected. The second heart sound is loud and single because of aortic atresia. Often the liver is enlarged secondary to congestive heart failure. The embryologic cause of the disease, as in the case of most congenital cardiac defects, is not fully known. The most useful diagnostic modality is the echocardiogram. The syndrome can be diagnosed by fetal echocardiography between 18 and 22 weeks of gestation. Differential diagnosis includes other left-sided obstructive lesions where the systemic circulation is dependent on ductal flow (critical aortic stenosis, coarctation of the aorta, interrupted aortic arch. Children with the syndrome require surgery as neonates, as they have duct-dependent systemic circulation. Currently, there are two major modalities, primary cardiac transplantation or a series of staged functionally univentricular palliations. The treatment chosen is dependent on the preference of the institution, its experience, and also preference. Although survival following initial surgical intervention has improved significantly over the last 20 years, significant mortality and morbidity are present for both surgical strategies. As a result pediatric cardiologists continue to be challenged by discussions with families regarding initial decision

  14. Visual field (United States)

    Perimetry; Tangent screen exam; Automated perimetry exam; Goldmann visual field exam; Humphrey visual field exam ... Confrontation visual field exam. This is a quick and basic check of the visual field. The health care provider ...

  15. Visual Impairment (United States)

    ... Staying Safe Videos for Educators Search English Español Visual Impairment KidsHealth / For Teens / Visual Impairment What's in ... with the brain, making vision impossible. What Is Visual Impairment? Many people have some type of visual ...

  16. Left atrial laceration with epicardial ligation device. (United States)

    Keating, Vincent P; Kolibash, Christopher P; Khandheria, Bijoy K; Bajwa, Tanvir; Sra, Jasbir; Kress, David C


    Many new devices and techniques are being developed to attempt a reduction in embolic stroke risk for patients with atrial fibrillation who are either unable or unwilling to maintain long-term anticoagulation. One of these new devices (LARIAT®, SentreHEART Inc., Redwood City, California, USA) employs delivery of an epicardial suture to ligate the left atrial appendage after percutaneous pericardial and transseptal access. This series presents three clinical cases that demonstrate a serious and recurrent complication of left atrial laceration and cardiac tamponade shortly following delivery of an epicardial suture ligation to the left atrial appendage. Three clinical cases are described in detail with pre- and postprocedure angiography and echocardiography as well as illustrations reflecting the surgeon's findings on direct visualization of the left atrial lacerations postligation. Potential hypotheses of each injury are examined in light of the case timelines and findings at sternotomy. There was no suggestion that tamponade was related to pericardial or transseptal access, but rather a complication with device delivery. These three patients quickly progressed to clinical cardiac tamponade despite attempted drainage, stressing the importance of cardiovascular surgery backup, including a cardiopulmonary bypass pump, when delivering novel, percutaneous ligation devices for the left atrial appendage.

  17. Isolated Left Pulmonary Artery Agenesis: A Case Report

    Directory of Open Access Journals (Sweden)

    Tansel Ansal Balcı


    Full Text Available Unilateral pulmonary artery agenesis without any cardiovascular malformation is a rare anomaly. We present the imaging findings of a patient who was diagnosed as isolated left pulmonary artery agenesis. A 27-year-old female patient was admitted to our hospital due to dyspnea during exercise for five years. Chest X-ray revealed minimally small left pulmonary hilum and left lung. She was admitted to our clinic with the suspicion of pulmonary artery pathology. Absent perfusion of the left lung with normal ventilation was visualized on scintigraphy. MDCT angiography of pulmonary arteries showed absent left main pulmonary artery with systemic collaterals around left hemithorax. Pulmonary artery agenesis can be asymptomatic and isolated until adulthood. Both scintigraphy and CT angiography images of pulmonary artery agenesis of a patient are rare in the literature. Pulmonary ventilation- perfusion scintigraphy can be used not only for pulmonary embolism but also pathologies involving pulmonary artery and its branches. (MIRT 2012;21:80-83

  18. Left Ventricular Assist Devices

    Directory of Open Access Journals (Sweden)

    Khuansiri Narajeenron


    Full Text Available Audience: The audience for this classic team-based learning (cTBL session is emergency medicine residents, faculty, and students; although this topic is applicable to internal medicine and family medicine residents. Introduction: A left ventricular assist device (LVAD is a mechanical circulatory support device that can be placed in critically-ill patients who have poor left ventricular function. After LVAD implantation, patients have improved quality of life.1 The number of LVAD patients worldwide continues to rise. Left-ventricular assist device patients may present to the emergency department (ED with severe, life-threatening conditions. It is essential that emergency physicians have a good understanding of LVADs and their complications. Objectives: Upon completion of this cTBL module, the learner will be able to: 1 Properly assess LVAD patients’ circulatory status; 2 appropriately resuscitate LVAD patients; 3 identify common LVAD complications; 4 evaluate and appropriately manage patients with LVAD malfunctions. Method: The method for this didactic session is cTBL.

  19. Caffeine improves left hemisphere processing of positive words. (United States)

    Kuchinke, Lars; Lux, Vanessa


    A positivity advantage is known in emotional word recognition in that positive words are consistently processed faster and with fewer errors compared to emotionally neutral words. A similar advantage is not evident for negative words. Results of divided visual field studies, where stimuli are presented in either the left or right visual field and are initially processed by the contra-lateral brain hemisphere, point to a specificity of the language-dominant left hemisphere. The present study examined this effect by showing that the intake of caffeine further enhanced the recognition performance of positive, but not negative or neutral stimuli compared to a placebo control group. Because this effect was only present in the right visual field/left hemisphere condition, and based on the close link between caffeine intake and dopaminergic transmission, this result points to a dopaminergic explanation of the positivity advantage in emotional word recognition.

  20. Caffeine improves left hemisphere processing of positive words.

    Directory of Open Access Journals (Sweden)

    Lars Kuchinke

    Full Text Available A positivity advantage is known in emotional word recognition in that positive words are consistently processed faster and with fewer errors compared to emotionally neutral words. A similar advantage is not evident for negative words. Results of divided visual field studies, where stimuli are presented in either the left or right visual field and are initially processed by the contra-lateral brain hemisphere, point to a specificity of the language-dominant left hemisphere. The present study examined this effect by showing that the intake of caffeine further enhanced the recognition performance of positive, but not negative or neutral stimuli compared to a placebo control group. Because this effect was only present in the right visual field/left hemisphere condition, and based on the close link between caffeine intake and dopaminergic transmission, this result points to a dopaminergic explanation of the positivity advantage in emotional word recognition.

  1. Left Ventricular Pseudoaneurysm Perceived as a Left Lung Mass

    Directory of Open Access Journals (Sweden)

    Ugur Gocen


    Full Text Available Left ventricular pseudo-aneurysm is a rare complication of aneurysmectomy. We present a case of surgically-treated left ventricular pseudo-aneurysm which was diagnosed three years after coronary artery bypass grafting and left ventricular aneurysmectomy. The presenting symptoms, diagnostic evaluation and surgical repair are described. [Cukurova Med J 2013; 38(1.000: 123-125

  2. Left Ventricle Pseudoaneurysm: Contribution of Multimodality Imaging to the Diagnosis

    Directory of Open Access Journals (Sweden)

    Ellenga Mbolla Bertrand Fikahem


    Full Text Available The left ventricle pseudoaneurysm is an anomaly of the left ventricle and is severed and joined with a pocket look. There may be secondary to a myocardial infarction, trauma, or surgical procedure. Sometimes the cause is not found. Complications are heart failure, arrhythmias, vascular embolism, and sudden death. The treatment is surgical only. The authors report the case of a black patient of 64 years old, without medical history, had seen to a deformation of the cardiac shadow in radiography. The left ventricle pseudoaneurysm and in situ thrombus are visualized in echocardiography and CT scan. The patient is waiting for heart surgery.

  3. Robotic-assisted excision of a left ventricular thrombus. (United States)

    Lutz, Charles J; Bhamidipati, Castigliano M; Ford, Brant; Swartz, Mike; Hauser, Michael; Kyobe, Moses; Dilip, Karikehalli


    : Left ventricular thrombus is a rare entity usually associated with myocardial infarction. The daVinci Surgical System (Intuitive Surgical, Inc., Sunnyvale, Calif) offers excellent visualization of the mitral subvalvular apparatus and should provide an effective means to excise a left ventricular mass. : A 34-year-old man presented to an outside institution with fever of unknown origin and ulcerative colitis. As part of this workup, he underwent a transthoracic echocardiogram and subsequently a transesophageal echocardiogram that showed a 2-cm left ventricular apical pedunculated mass. He was referred to our institution for excision of this ventricular mass. Because of the pedunculated nature of the mass, he was deemed a candidate for a robotic-assisted minimally invasive approach. : The patient underwent successful robotic-assisted excision of a left ventricular mass. Total robotic time was 15 minutes. Pathology revealed that the mass was a left ventricular thrombus. The patient experienced an uneventful recovery and was discharged home in 4 days. : Left ventricular mass excision can be safely performed with the daVinci Surgical System. The daVinci Surgical System offers excellent visualization of the entire left ventricular cavity.

  4. Why Dora Left

    DEFF Research Database (Denmark)

    Gammelgård, Judy


    The question of why Dora left her treatment before it was brought to a satisfactory end and the equally important question of why Freud chose to publish this problematic and fragmentary story have both been dealt with at great length by Freud’s successors. Dora has been read by analysts, literary...... critics, and not least by feminists. The aim of this paper is to point out the position Freud took toward his patient. Dora stands out as the one case among Freud’s 5 great case stories that has a female protagonist, and reading the case it becomes clear that Freud stumbled because of an unresolved...... problem toward femininity, both Dora’s and his own. In Dora, it is argued, Freud took a new stance toward the object of his investigation, speaking from the position of the master. Freud presents himself as the one who knows, in great contrast to the position he takes when unraveling the dream. Here he...

  5. Visual Culture and Visual Literacy

    Directory of Open Access Journals (Sweden)

    Sibel Onursoy


    Full Text Available Recently visual literacy gains importance in the context of understanding the rising visual culture products, thinking about them and producing these products. The purpose of this article examines the concept of visual literacy that is the relationship with visual culture depending on the literature. Visual literacy is one of the multiple literatures that emerge from the development of information and information dissemination forms. Visual literacy is an interdisciplinary concept and associated with some areas, such as graphic design, visual arts, architectural engineering, industrial product design, visual communication and media literacy. Visual culture covers every human product, so visual products that we face in everyday life and visual realities with abundant alternatives constitute our daily life itself. Sometimes, this confusing visual understanding creates a gap between contemporary cultural richness and what can be observed.

  6. Plasticity and stability of the visual system in human achiasma

    NARCIS (Netherlands)

    Hoffmann, M.B.; Kaule, F.; Levin, N.; Masuda, Y.; Kumar, A.; Gottlob, I.; Horiguchi, H.; Dougherty, R.F.; Stadler, J.; Wolynski, B.; Speck, O.; Kanowski, M.; Liao, Y.J.; Wandell, B.A.; Dumoulin, S.O.


    The absence of the optic chiasm is an extraordinary and extreme abnormality in the nervous system. The abnormality produces highly atypical functional responses in the cortex, including overlapping hemifield representations and bilateral population receptive fields in both striate and

  7. The impact of early visual cortex transcranial magnetic stimulation on visual working memory precision and guess rate (United States)

    van de Ven, Vincent G.; Tong, Frank; Sack, Alexander T.


    Neuroimaging studies have demonstrated that activity patterns in early visual areas predict stimulus properties actively maintained in visual working memory. Yet, the mechanisms by which such information is represented remain largely unknown. In this study, observers remembered the orientations of 4 briefly presented gratings, one in each quadrant of the visual field. A 10Hz Transcranial Magnetic Stimulation (TMS) triplet was applied directly at stimulus offset, or midway through a 2-second delay, targeting early visual cortex corresponding retinotopically to a sample item in the lower hemifield. Memory for one of the four gratings was probed at random, and participants reported this orientation via method of adjustment. Recall errors were smaller when the visual field location targeted by TMS overlapped with that of the cued memory item, compared to errors for stimuli probed diagonally to TMS. This implied topographic storage of orientation information, and a memory-enhancing effect at the targeted location. Furthermore, early pulses impaired performance at all four locations, compared to late pulses. Next, response errors were fit empirically using a mixture model to characterize memory precision and guess rates. Memory was more precise for items proximal to the pulse location, irrespective of pulse timing. Guesses were more probable with early TMS pulses, regardless of stimulus location. Thus, while TMS administered at the offset of the stimulus array might disrupt early-phase consolidation in a non-topographic manner, TMS also boosts the precise representation of an item at its targeted retinotopic location, possibly by increasing attentional resources or by injecting a beneficial amount of noise. PMID:28384347

  8. The impact of early visual cortex transcranial magnetic stimulation on visual working memory precision and guess rate. (United States)

    Rademaker, Rosanne L; van de Ven, Vincent G; Tong, Frank; Sack, Alexander T


    Neuroimaging studies have demonstrated that activity patterns in early visual areas predict stimulus properties actively maintained in visual working memory. Yet, the mechanisms by which such information is represented remain largely unknown. In this study, observers remembered the orientations of 4 briefly presented gratings, one in each quadrant of the visual field. A 10Hz Transcranial Magnetic Stimulation (TMS) triplet was applied directly at stimulus offset, or midway through a 2-second delay, targeting early visual cortex corresponding retinotopically to a sample item in the lower hemifield. Memory for one of the four gratings was probed at random, and participants reported this orientation via method of adjustment. Recall errors were smaller when the visual field location targeted by TMS overlapped with that of the cued memory item, compared to errors for stimuli probed diagonally to TMS. This implied topographic storage of orientation information, and a memory-enhancing effect at the targeted location. Furthermore, early pulses impaired performance at all four locations, compared to late pulses. Next, response errors were fit empirically using a mixture model to characterize memory precision and guess rates. Memory was more precise for items proximal to the pulse location, irrespective of pulse timing. Guesses were more probable with early TMS pulses, regardless of stimulus location. Thus, while TMS administered at the offset of the stimulus array might disrupt early-phase consolidation in a non-topographic manner, TMS also boosts the precise representation of an item at its targeted retinotopic location, possibly by increasing attentional resources or by injecting a beneficial amount of noise.

  9. Non-compact left ventricle/hypertrabeculated left ventricle

    International Nuclear Information System (INIS)

    Restrepo, Gustavo; Castano, Rafael; Marmol, Alejandro


    Non-compact left ventricle/hypertrabeculated left ventricle is a myocardiopatie produced by an arrest of the normal left ventricular compaction process during the early embryogenesis. It is associated to cardiac anomalies (congenital cardiopaties) as well as to extracardial conditions (neurological, facial, hematologic, cutaneous, skeletal and endocrinological anomalies). This entity is frequently unnoticed, being diagnosed only in centers with great experience in the diagnosis and treatment of myocardiopathies. Many cases of non-compact left ventricle have been initially misdiagnosed as hypertrophic myocardiopatie, endocardial fibroelastosis, dilated cardiomyopatie, restrictive cardiomyopathy and endocardial fibrosis. It is reported the case of a 74 years old man with a history of chronic arterial hypertension and diabetes mellitus, prechordial chest pain and mild dyspnoea. An echocardiogram showed signs of non-compact left ventricle with prominent trabeculations and deep inter-trabecular recesses involving left ventricular apical segment and extending to the lateral and inferior walls. Literature on this topic is reviewed

  10. Rapid estimation of left ventricular ejection fraction in acute myocardial infarction by echocardiographic wall motion analysis

    DEFF Research Database (Denmark)

    Berning, J; Rokkedal Nielsen, J; Launbjerg, J


    Echocardiographic estimates of left ventricular ejection fraction (ECHO-LVEF) in acute myocardial infarction (AMI) were obtained by a new approach, using visual analysis of left ventricular wall motion in a nine-segment model. The method was validated in 41 patients using radionuclide ventriculog......Echocardiographic estimates of left ventricular ejection fraction (ECHO-LVEF) in acute myocardial infarction (AMI) were obtained by a new approach, using visual analysis of left ventricular wall motion in a nine-segment model. The method was validated in 41 patients using radionuclide...

  11. Mechanical discordance between left atrium and left atrial appendage

    Directory of Open Access Journals (Sweden)

    Arash Khamooshian


    Full Text Available During standard transesophageal echocardiographic examinations in sinus rhythm (SR patients, the left atrial appendage (LAA is not routinely assessed with Doppler. Despite having a SR, it is still possible to have irregular activity in the LAA. This situation is even more important for SR patients where assessment of the left atrium is often foregone. We describe a case where we encountered this situation and briefly review how to assess the left atrium and its appendage in such a case scenario.

  12. [Left-handedness and health]. (United States)

    Milenković, Sanja; Belojević, Goran; Kocijancić, Radojka


    Hand dominance is defined as a proneness to use one hand rather than another in performing the majority of activities and this is the most obvious example of cerebral lateralization and an exclusive human characteristic. Left-handed people comprise 6-14% of the total population, while in Serbia, this percentage is 5-10%, moving from undeveloped to developed environments, where a socio-cultural pressure is less present. There is no agreement between investigators who in fact may be considered a left-handed person, about the percentage of left-handers in the population and about the etiology of left-handedness. In the scientific literature left-handedness has been related to health disorders (spine deformities, immunological disorders, migraine, neurosis, depressive psychosis, schizophrenia, insomnia, homosexuality, diabetes mellitus, arterial hypertension, sleep apnea, enuresis nocturna and Down Syndrome), developmental disorders (autism, dislexia and sttutering) and traumatism. The most reliable scientific evidences have been published about the relationship between left-handedness and spinal deformities in school children in puberty and with traumatism in general population. The controversy of other results in up-to-now investigations of health aspects of left-handedness may partly be explained by a scientific disagreement whether writing with the left hand is a sufficient criterium for left-handedness, or is it necessary to investigate other parameters for laterality assessment. Explanation of health aspects of left-handedness is dominantly based on Geschwind-Galaburda model about "anomalous" cerebral domination, as a consequence of hormonal disbalance.

  13. Visual art and visual perception

    NARCIS (Netherlands)

    Koenderink, Jan J.


    Visual art and visual perception ‘Visual art’ has become a minor cul-de-sac orthogonal to THE ART of the museum directors and billionaire collectors. THE ART is conceptual, instead of visual. Among its cherished items are the tins of artist’s shit (Piero Manzoni, 1961, Merda d’Artista) “worth their

  14. Flow visualization

    CERN Document Server

    Merzkirch, Wolfgang


    Flow Visualization describes the most widely used methods for visualizing flows. Flow visualization evaluates certain properties of a flow field directly accessible to visual perception. Organized into five chapters, this book first presents the methods that create a visible flow pattern that could be investigated by visual inspection, such as simple dye and density-sensitive visualization methods. It then deals with the application of electron beams and streaming birefringence. Optical methods for compressible flows, hydraulic analogy, and high-speed photography are discussed in other cha

  15. Validation of semi-automatic segmentation of the left atrium (United States)

    Rettmann, M. E.; Holmes, D. R., III; Camp, J. J.; Packer, D. L.; Robb, R. A.


    and between raters, and accurate when compared to the truth model. Finally, we generated a visualization to assess the spatial variability in the segmentation errors between the semi-automatic approach and the truth model. The visualization demonstrates the highest errors occur at the boundaries between the left atium and pulmonary veins as well as the left atrium and left atrial appendage. In conclusion, we describe a semi-automatic approach for left atrial segmentation that demonstrates repeatability and accuracy, with the advantage of significant time reduction in user interaction time.

  16. Myxoma of the Left Ventricle (United States)

    Novoa, José; Delgado, Antonio; Alonso, Ana


    This report concerns a 69-year-old woman who presented with an asymptomatic myxoma in the left ventricle. The tumor was successfully excised. We provide a very brief review of 72 other published cases of surgically treated left ventricular myxoma. PMID:25120392

  17. Left ventricular hypertrophy in athletes. (United States)

    Douglas, P S; O'Toole, M L; Katz, S E; Ginsburg, G S; Hiller, W D; Laird, R H


    Left ventricular wall thickness >1.3 cm, septal-to-posterior wall ratios > 1.5, diastolic left ventricular size >6.0 cm, and eccentric or concentric remodeling are rare in athletes. Values outside of these cutoffs in an athlete of any age probably represent a pathologic state.

  18. The Left-Handed Writer. (United States)

    Bloodsworth, James Gaston

    Contrary to the beliefs of many, right-handedness is not a single factor existing in almost all people, with a few exceptions termed left-handed: neither extreme exists independently of the other. During the first 4 years of life there is a period of fluctuation between right and left-handed dominance. Statistics and findings vary in determining…

  19. Two Lefts in Latin America?

    DEFF Research Database (Denmark)

    Christensen, Steen Fryba

    In this working paper I list five researchers' categorizations of the Latin American left in power (april 2006) in a schematic form. The most important criteria for the categorizations are given.......In this working paper I list five researchers' categorizations of the Latin American left in power (april 2006) in a schematic form. The most important criteria for the categorizations are given....

  20. A Giant Left Atrial Myxoma

    Directory of Open Access Journals (Sweden)

    Medhat F. Zaher


    Full Text Available Atrial myxomas are the most common primary cardiac tumors. Patients with left atrial myxomas generally present with mechanical obstruction of blood flow, systemic embolization, and constitutional symptoms. We present a case of an unusually large left atrial myxoma discovered incidentally in a patient with longstanding dyspnea being managed as bronchial asthma.

  1. Left-handedness and health

    Directory of Open Access Journals (Sweden)

    Milenković Sanja


    Full Text Available Hand dominance is defined as a proneness to use one hand rather than another in performing the majority of activities and this is the most obvious example of cerebral lateralization and an exclusive human characteristic. Left-handed people comprise 6-14% of the total population, while in Serbia, this percentage is 5-10%, moving from undeveloped to developed environments, where a socio-cultural pressure is less present. There is no agreement between investigators who in fact may be considered a left-handed person, about the percentage of left-handers in the population and about the etiology of left-handedness. In the scientific literature left-handedness has been related to health disorders (spine deformities, immunological disorders, migraine, neurosis, depressive psychosis, schizophrenia, insomnia, homosexuality, diabetes mellitus, arterial hypertension, sleep apnea, enuresis nocturna and Down Syndrome, developmental disorders (autism, dislexia and sttutering and traumatism. The most reliable scientific evidences have been published about the relationship between left-handedness and spinal deformities in school children in puberty and with traumatism in general population. The controversy of other results in up-to-now investigations of health aspects of left-handedness may partly be explained by a scientific disagreement whether writing with the left hand is a sufficient criterium for left-handedness, or is it necessary to investigate other parameters for laterality assessment. Explanation of health aspects of left-handedness is dominantly based on Geschwind-Galaburda model about 'anomalous' cerebral domination, as a consequence of hormonal disbalance. .

  2. Left ventricular wall stress compendium. (United States)

    Zhong, L; Ghista, D N; Tan, R S


    Left ventricular (LV) wall stress has intrigued scientists and cardiologists since the time of Lame and Laplace in 1800s. The left ventricle is an intriguing organ structure, whose intrinsic design enables it to fill and contract. The development of wall stress is intriguing to cardiologists and biomedical engineers. The role of left ventricle wall stress in cardiac perfusion and pumping as well as in cardiac pathophysiology is a relatively unexplored phenomenon. But even for us to assess this role, we first need accurate determination of in vivo wall stress. However, at this point, 150 years after Lame estimated left ventricle wall stress using the elasticity theory, we are still in the exploratory stage of (i) developing left ventricle models that properly represent left ventricle anatomy and physiology and (ii) obtaining data on left ventricle dynamics. In this paper, we are responding to the need for a comprehensive survey of left ventricle wall stress models, their mechanics, stress computation and results. We have provided herein a compendium of major type of wall stress models: thin-wall models based on the Laplace law, thick-wall shell models, elasticity theory model, thick-wall large deformation models and finite element models. We have compared the mean stress values of these models as well as the variation of stress across the wall. All of the thin-wall and thick-wall shell models are based on idealised ellipsoidal and spherical geometries. However, the elasticity model's shape can vary through the cycle, to simulate the more ellipsoidal shape of the left ventricle in the systolic phase. The finite element models have more representative geometries, but are generally based on animal data, which limits their medical relevance. This paper can enable readers to obtain a comprehensive perspective of left ventricle wall stress models, of how to employ them to determine wall stresses, and be cognizant of the assumptions involved in the use of specific models.

  3. Monocular Visual Deprivation Suppresses Excitability in Adult Human Visual Cortex

    DEFF Research Database (Denmark)

    Lou, Astrid Rosenstand; Madsen, Kristoffer Hougaard; Paulson, Olaf Bjarne


    The adult visual cortex maintains a substantial potential for plasticity in response to a change in visual input. For instance, transcranial magnetic stimulation (TMS) studies have shown that binocular deprivation (BD) increases the cortical excitability for inducing phosphenes with TMS. Here, we...... employed TMS to trace plastic changes in adult visual cortex before, during, and after 48 h of monocular deprivation (MD) of the right dominant eye. In healthy adult volunteers, MD-induced changes in visual cortex excitability were probed with paired-pulse TMS applied to the left and right occipital cortex....... Stimulus–response curves were constructed by recording the intensity of the reported phosphenes evoked in the contralateral visual field at range of TMS intensities. Phosphene measurements revealed that MD produced a rapid and robust decrease in cortical excitability relative to a control condition without...

  4. Data visualization

    CERN Document Server

    Azzam, Tarek


    Do you communicate data and information to stakeholders? In Part 1, we introduce recent developments in the quantitative and qualitative data visualization field and provide a historical perspective on data visualization, its potential role in evaluation practice, and future directions. Part 2 delivers concrete suggestions for optimally using data visualization in evaluation, as well as suggestions for best practices in data visualization design. It focuses on specific quantitative and qualitative data visualization approaches that include data dashboards, graphic recording, and geographic information systems (GIS). Readers will get a step-by-step process for designing an effective data dashboard system for programs and organizations, and various suggestions to improve their utility.

  5. Lateralized visual behavior in bottlenose dolphins (Tursiops truncatus) performing audio-visual tasks: the right visual field advantage. (United States)

    Delfour, F; Marten, K


    Analyzing cerebral asymmetries in various species helps in understanding brain organization. The left and right sides of the brain (lateralization) are involved in different cognitive and sensory functions. This study focuses on dolphin visual lateralization as expressed by spontaneous eye preference when performing a complex cognitive task; we examine lateralization when processing different visual stimuli displayed on an underwater touch-screen (two-dimensional figures, three-dimensional figures and dolphin/human video sequences). Three female bottlenose dolphins (Tursiops truncatus) were submitted to a 2-, 3- or 4-, choice visual/auditory discrimination problem, without any food reward: the subjects had to correctly match visual and acoustic stimuli together. In order to visualize and to touch the underwater target, the dolphins had to come close to the touch-screen and to position themselves using monocular vision (left or right eye) and/or binocular naso-ventral vision. The results showed an ability to associate simple visual forms and auditory information using an underwater touch-screen. Moreover, the subjects showed a spontaneous tendency to use monocular vision. Contrary to previous findings, our results did not clearly demonstrate right eye preference in spontaneous choice. However, the individuals' scores of correct answers were correlated with right eye vision, demonstrating the advantage of this visual field in visual information processing and suggesting a left hemispheric dominance. We also demonstrated that the nature of the presented visual stimulus does not seem to have any influence on the animals' monocular vision choice.

  6. Left main percutaneous coronary intervention. (United States)

    Teirstein, Paul S; Price, Matthew J


    The introduction of drug-eluting stents and advances in catheter techniques have led to increasing acceptance of percutaneous coronary intervention (PCI) as a viable alternative to coronary artery bypass graft (CABG) for unprotected left main disease. Current guidelines state that it is reasonable to consider unprotected left main PCI in patients with low to intermediate anatomic complexity who are at increased surgical risk. Data from randomized trials involving patients who are candidates for either treatment strategy provide novel insight into the relative safety and efficacy of PCI for this lesion subset. Herein, we review the current data comparing PCI with CABG for left main disease, summarize recent guideline recommendations, and provide an update on technical considerations that may optimize clinical outcomes in left main PCI. Copyright © 2012 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

  7. Left bundle-branch block

    DEFF Research Database (Denmark)

    Risum, Niels; Strauss, David; Sogaard, Peter


    The relationship between myocardial electrical activation by electrocardiogram (ECG) and mechanical contraction by echocardiography in left bundle-branch block (LBBB) has never been clearly demonstrated. New strict criteria for LBBB based on a fundamental understanding of physiology have recently...

  8. Dabigatran for left ventricular thrombus

    Directory of Open Access Journals (Sweden)

    Satishkumar Kolekar


    Dabigatran is a reversible direct thrombin inhibitor and currently approved for the prevention of thromboembolic episodes in non-valvar atrial fibrillation. This case demonstrates possible thrombolytic properties of dabigatran in resolution of left ventricular thrombus.

  9. Apraxia in left-handers. (United States)

    Goldenberg, Georg


    In typical right-handed patients both apraxia and aphasia are caused by damage to the left hemisphere, which also controls the dominant right hand. In left-handed subjects the lateralities of language and of control of the dominant hand can dissociate. This permits disentangling the association of apraxia with aphasia from that with handedness. Pantomime of tool use, actual tool use and imitation of meaningless hand and finger postures were examined in 50 consecutive left-handed subjects with unilateral hemisphere lesions. There were three aphasic patients with pervasive apraxia caused by left-sided lesions. As the dominant hand is controlled by the right hemisphere, they constitute dissociations of apraxia from handedness. Conversely there were also three patients with pervasive apraxia caused by right brain lesions without aphasia. They constitute dissociations of apraxia from aphasia. Across the whole group of patients dissociations from handedness and from aphasia were observed for all manifestations of apraxia, but their frequency depended on the type of apraxia. Defective pantomime and defective tool use occurred rarely without aphasia, whereas defective imitation of hand, but not finger, postures was more frequent after right than left brain damage. The higher incidence of defective imitation of hand postures in right brain damage was mainly due to patients who had also hemi-neglect. This interaction alerts to the possibility that the association of right hemisphere damage with apraxia has to do with spatial aptitudes of the right hemisphere rather than with its control of the dominant left hand. Comparison with data from right-handed patients showed no differences between the severity of apraxia for imitation of hand or finger postures, but impairment on pantomime of tool use was milder in apraxic left-handers than in apraxic right-handers. This alleviation of the severity of apraxia corresponded with a similar alleviation of the severity of aphasia as

  10. Left ventricular apical ballooning syndrome

    International Nuclear Information System (INIS)

    Rahman, N.; Tai, J.; Soofi, A.


    The transient left ventricular apical ballooning syndrome, also known as Takotsubo cardiomyopathy, is characterized by transient left ventricular dysfunction in the absence of obstructive epicardial coronary disease. Although the syndrome has been reported in Japan since 1990, it is rare in other regions. Rapid recognition of the syndrome can modify the diagnostic and therapeutic attitude i.e. avoiding thrombolysis and performing catheterization in the acute phase. (author)

  11. Semantic dementia and the left and right temporal lobes. (United States)

    Snowden, Julie S; Harris, Jennifer M; Thompson, Jennifer C; Kobylecki, Christopher; Jones, Matthew; Richardson, Anna M; Neary, David


    Semantic dementia, a circumscribed disorder of semantic knowledge, provides a unique model for understanding the neural basis for semantic representation. The study addressed areas of contention: the relative roles of the left and right temporal lobe, the contribution of anterior versus posterior temporal cortex and the status of the anterior temporal lobes as amodal hub. Naming and word comprehension was examined in 41 semantic dementia patients, 31 with left-predominant and 10 right-predominant atrophy. In keeping with expectation, naming and comprehension were significantly poorer in left-predominant patients. Structural magnetic resonance image analysis, using a visual rating scale, showed strong inverse correlations between naming scores and severity of both left anterior and posterior temporal lobe atrophy. By contrast, comprehension performance was more strongly correlated with left posterior temporal atrophy. Analysis of naming errors revealed a correlation between anterior temporal atrophy and associative/functional descriptive responses, implying availability of semantic information. By contrast, 'don't know' responses, indicative of loss of semantic knowledge, were linked to left posterior temporal lobe atrophy. Semantic errors, the hallmark of semantic dementia, were linked to right hemisphere atrophy, especially the right posterior temporal lobe. Matched visual-verbal tasks (famous face and name identification, Pyramids and Palm trees pictures and words, animal knowledge from 3-D models and animal names) administered to nine patients elicited variable correspondence between performance on nonverbal and verbal versions of the task. Marked performance dissociations were demonstrated in some patients: poorer understanding of names/words in left-predominant patients and of faces/pictures/models in right-predominant cases. The findings are compatible with the notion of the anterior temporal lobes as areas of convergence, but are less easily accommodated

  12. Left Main Coronary Artery Aneurysm

    Directory of Open Access Journals (Sweden)

    Hossein Doustkami


    Full Text Available Aneurysms of the left main coronary artery are exceedingly rare clinical entities, encountered incidentally in approximately 0.1% of patients who undergo routine angiography. The most common cause of coronary artery aneurysms is atherosclerosis. Angiography is the gold standard for diagnosis and treatment. Depending on the severity of the coexisting coronary stenosis, patients with left main coronary artery aneurysms can be effectively managed either surgically or pharmacologically. We herein report a case of left main coronary artery aneurysm in a 72-year-old man with a prior history of hypertension presenting to our hospital because of unstable angina. The electrocardiogram showed ST-segment depression and T-wave inversion in the precordial leads. All the data of blood chemistry were normal. Echocardiography showed akinetic anterior wall, septum, and apex, mild mitral regurgitation and ejection fraction of 45%. Coronary angiography revealed a saccular aneurysm of the left main coronary artery with significant stenosis in the left anterior descending, left circumflex, and right coronary artery. The patient immediately underwent coronary artery bypass grafting and ligation of the aneurysm. At six months’ follow-up, he remained asymptomatic.

  13. Right colon cancer: Left behind. (United States)

    Gervaz, P; Usel, M; Rapiti, E; Chappuis, P; Neyroud-Kaspar, I; Bouchardy, C


    Prognosis of colon cancer (CC) has steadily improved during the past three decades. This trend, however, may vary according to proximal (right) or distal (left) tumor location. We studied if improvement in survival was greater for left than for right CC. We included all CC recorded at the Geneva population-based registry between 1980 and 2006. We compared patients, tumor and treatment characteristics between left and right CC by logistic regression and compared CC specific survival by Cox models taking into account putative confounders. We also compared changes in survival between CC location in early and late years of observation. Among the 3396 CC patients, 1334 (39%) had right-sided and 2062 (61%) left-sided tumors. In the early 1980s, 5-year specific survival was identical for right and left CCs (49% vs. 48%). During the study period, a dramatic improvement in survival was observed for patients with left-sided cancers (Hazard ratio [HR]: 0.42, 95% confidence interval [CI]: 0.29-0.62, p colon cancer patients, those with right-sided lesions have by far the worse prognosis. Change of strategic management in this subgroup is warranted. Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. Long-Term Visuo-Gustatory Appetitive and Aversive Conditioning Potentiate Human Visual Evoked Potentials

    Directory of Open Access Journals (Sweden)

    Gert R. J. Christoffersen


    Full Text Available Human recognition of foods and beverages are often based on visual cues associated with flavors. The dynamics of neurophysiological plasticity related to acquisition of such long-term associations has only recently become the target of investigation. In the present work, the effects of appetitive and aversive visuo-gustatory conditioning were studied with high density EEG-recordings focusing on late components in the visual evoked potentials (VEPs, specifically the N2-P3 waves. Unfamiliar images were paired with either a pleasant or an unpleasant juice and VEPs evoked by the images were compared before and 1 day after the pairings. In electrodes located over posterior visual cortex areas, the following changes were observed after conditioning: the amplitude from the N2-peak to the P3-peak increased and the N2 peak delay was reduced. The percentage increase of N2-to-P3 amplitudes was asymmetrically distributed over the posterior hemispheres despite the fact that the images were bilaterally symmetrical across the two visual hemifields. The percentage increases of N2-to-P3 amplitudes in each experimental subject correlated with the subject’s evaluation of positive or negative hedonic valences of the two juices. The results from 118 scalp electrodes gave surface maps of theta power distributions showing increased power over posterior visual areas after the pairings. Source current distributions calculated from swLORETA revealed that visual evoked currents rose as a result of conditioning in five cortical regions—from primary visual areas and into the inferior temporal gyrus (ITG. These learning-induced changes were seen after both appetitive and aversive training while a sham trained control group showed no changes. It is concluded that long-term visuo-gustatory conditioning potentiated the N2-P3 complex, and it is suggested that the changes are regulated by the perceived hedonic valence of the US.

  15. The temporal evolution of electromagnetic markers sensitive to the capacity limits of visual short-term memory

    Directory of Open Access Journals (Sweden)

    Daniel James Mitchell


    Full Text Available An electroencephalographic (EEG marker of the limited contents of human visual short-term memory (VSTM has previously been described. Termed contralateral delay activity (CDA, this consists of a sustained, posterior, negative potential that correlates with memory load and is greatest contralateral to the remembered hemifield. The current investigation replicates this finding and uses magnetoencephalography (MEG to characterise its magnetic counterparts and their neural generators as they evolve throughout the memory delay. A parametric manipulation of memory load, within and beyond capacity limits, allows separation of signals that asymptote with behavioural VSTM performance from additional responses that contribute to a linear increase with set-size. Both EEG and MEG yielded bilateral signals that track the number of objects held in memory, and contralateral signals that are independent of memory load. In MEG, unlike EEG, the contralateral interaction between hemisphere and item load is much weaker, suggesting that bilateral and contralateral markers of memory load reflect distinct sources to which EEG and MEG are differentially sensitive. Nonetheless, source estimation allowed both the bilateral and the weaker contralateral capacity-limited responses to be localised, along with a load-independent contralateral signal. Sources of global and hemisphere-specific signals all localised to the posterior intraparietal sulcus during the early delay. However the bilateral load response peaked earlier and its generators shifted later in the delay. Therefore the hemifield-specific response may be more closely tied to memory maintenance while the global load response may be involved in initial processing of a limited number of attended objects, such as their individuation or consolidation into memory.

  16. The temporal evolution of electromagnetic markers sensitive to the capacity limits of visual short-term memory. (United States)

    Mitchell, Daniel J; Cusack, Rhodri


    An electroencephalographic (EEG) marker of the limited contents of human visual short-term memory (VSTM) has previously been described. Termed contralateral delay activity, this consists of a sustained, posterior, negative potential that correlates with memory load and is greatest contralateral to the remembered hemifield. The current investigation replicates this finding and uses magnetoencephalography (MEG) to characterize its magnetic counterparts and their neural generators as they evolve throughout the memory delay. A parametric manipulation of memory load, within and beyond capacity limits, allows separation of signals that asymptote with behavioral VSTM performance from additional responses that contribute to a linear increase with set-size. Both EEG and MEG yielded bilateral signals that track the number of objects held in memory, and contralateral signals that are independent of memory load. In MEG, unlike EEG, the contralateral interaction between hemisphere and item load is much weaker, suggesting that bilateral and contralateral markers of memory load reflect distinct sources to which EEG and MEG are differentially sensitive. Nonetheless, source estimation allowed both the bilateral and the weaker contralateral capacity-limited responses to be localized, along with a load-independent contralateral signal. Sources of global and hemisphere-specific signals all localized to the posterior intraparietal sulcus during the early delay. However the bilateral load response peaked earlier and its generators shifted later in the delay. Therefore the hemifield-specific response may be more closely tied to memory maintenance while the global load response may be involved in initial processing of a limited number of attended objects, such as their individuation or consolidation into memory.

  17. Visualization of Uncertainty (United States)

    Jones, P. W.; Strelitz, R. A.


    The output of a simulation is best comprehended through the agency and methods of visualization, but a vital component of good science is knowledge of uncertainty. While great strides have been made in the quantification of uncertainty, especially in simulation, there is still a notable gap: there is no widely accepted means of simultaneously viewing the data and the associated uncertainty in one pane. Visualization saturates the screen, using the full range of color, shadow, opacity and tricks of perspective to display even a single variable. There is no room in the visualization expert's repertoire left for uncertainty. We present a method of visualizing uncertainty without sacrificing the clarity and power of the underlying visualization that works as well in 3-D and time-varying visualizations as it does in 2-D. At its heart, it relies on a principal tenet of continuum mechanics, replacing the notion of value at a point with a more diffuse notion of density as a measure of content in a region. First, the uncertainties calculated or tabulated at each point are transformed into a piecewise continuous field of uncertainty density . We next compute a weighted Voronoi tessellation of a user specified N convex polygonal/polyhedral cells such that each cell contains the same amount of uncertainty as defined by . The problem thus devolves into minimizing . Computation of such a spatial decomposition is O(N*N ), and can be computed iteratively making it possible to update easily over time as well as faster. The polygonal mesh does not interfere with the visualization of the data and can be easily toggled on or off. In this representation, a small cell implies a great concentration of uncertainty, and conversely. The content weighted polygons are identical to the cartogram familiar to the information visualization community in the depiction of things voting results per stat. Furthermore, one can dispense with the mesh or edges entirely to be replaced by symbols or glyphs

  18. Traffic Visualization

    DEFF Research Database (Denmark)

    Picozzi, Matteo; Verdezoto, Nervo; Pouke, Matti


    In this paper, we present a space-time visualization to provide city's decision-makers the ability to analyse and uncover important "city events" in an understandable manner for city planning activities. An interactive Web mashup visualization is presented that integrates several visualization...... techniques to give a rapid overview of traffic data. We illustrate our approach as a case study for traffic visualization systems, using datasets from the city of Oulu that can be extended to other city planning activities. We also report the feedback of real users (traffic management employees, traffic police...... officers, city planners) to support our arguments....

  19. Distributed Visualization (United States)

    National Aeronautics and Space Administration — Distributed Visualization allows anyone, anywhere, to see any simulation, at any time. Development focuses on algorithms, software, data formats, data systems and...

  20. Visualization Laboratory (United States)

    Federal Laboratory Consortium — FUNCTION: Evaluates and improves the operational effectiveness of existing and emerging electronic warfare systems. By analyzing and visualizing simulation results...

  1. [Visual dependence after recent stroke]. (United States)

    Bonan, I; Derighetti, F; Gellez-Leman, M-C; Bradaï, N; Yelnik, A


    After chronic stroke, inability to use pertinent somatosensory or vestibular information have been described. The aim of the study was to determine whether visual dependence occurred early after stroke before rehabilitation. Thirty patients with recent hemiplegia (16 right and 14 left hemispheric stroke) performed the rod and frame test (RFT). Patients were asked to adjust the rod to the vertical position under 3 conditions: basically, with a frame tilted 18 degrees to the right and then with the frame tilted to the left. Bias in each condition (mean, SD) was recorded and compared to adjustments of the rod by 23 controls. Motor control, sensibility, functional level (functional independence measure), age, neglect, and then balance by the postural assessment scale for stroke were assessed. Fifty-six per cent (17/30) of patients but only 26% of controls were influenced by the tilt of the frame on the 2 sides (visual dependence). No correlation was found between visual dependence and the characteristics of the patients. Many patients with recent hemiplegia seem to rely on visual input. The mechanisms of such visual dependence are discussed. Rehabilitation programs should take into account the possible impairment of sensory organisation and should include exercises to be performed under visual disturbances.

  2. Emission computer tomography of the left ventricle

    Energy Technology Data Exchange (ETDEWEB)

    Semmler, W.; Felix, R.; Calder, D.; Golde, G.; Botsch, H.


    Tomographic studies and time-dependent tomograms on phantoms and patients were carried out using a 7-pinhole collimator in order to study the clinical value of ECG-triggered tomographic radionuclid ventriculography. A suitable computer programme has been developed. The results have shown that it is possible to evaluate local contraction abnormalities by this method. Using a left oblique position of the collimator (LAO (45/sup 0/) - cranial (15/sup 0/)), emission computer tomography is aligned with the longitudinal axis for the heart. In this way, a single projection is sufficient to show the montility of the anterior and posterior walls and of the septum. Hypokinesis, akinesis or dyskinesis can be recognised visually. The localisation and extent of the defect can be determined through the 7-pinhole collimator. Reconstructed images of the triggered radionuclide scintigrams show excellent marginal definition. In the RAO projection the left ventricle can be seen without superimposition and images obtained which equal those of a first-pass technique.

  3. Atlas-Based Mosaicing of Left Atrial 3-D Transesophageal Echocardiography Images

    NARCIS (Netherlands)

    Mulder, Harriët W.; van Stralen, Marijn; Ren, Ben; Haak, Alexander; Viergever, Max A.; Bosch, Johan G.; Pluim, JPW

    Transesophageal echocardiography (TEE) is a promising imaging modality used to guide cardiac interventions, such as catheter ablation for the treatment of cardiac arrhythmias. These procedures rely on good visualization of the left atrium and pulmonary veins. To visualize these structures in a

  4. Implicit Recognition Based on Lateralized Perceptual Fluency

    Directory of Open Access Journals (Sweden)

    Iliana M. Vargas


    Full Text Available In some circumstances, accurate recognition of repeated images in an explicit memory test is driven by implicit memory. We propose that this “implicit recognition” results from perceptual fluency that influences responding without awareness of memory retrieval. Here we examined whether recognition would vary if images appeared in the same or different visual hemifield during learning and testing. Kaleidoscope images were briefly presented left or right of fixation during divided-attention encoding. Presentation in the same visual hemifield at test produced higher recognition accuracy than presentation in the opposite visual hemifield, but only for guess responses. These correct guesses likely reflect a contribution from implicit recognition, given that when the stimulated visual hemifield was the same at study and test, recognition accuracy was higher for guess responses than for responses with any level of confidence. The dramatic difference in guessing accuracy as a function of lateralized perceptual overlap between study and test suggests that implicit recognition arises from memory storage in visual cortical networks that mediate repetition-induced fluency increments.

  5. Aphasia following left thalamic hemorrhage

    International Nuclear Information System (INIS)

    Makishita, Hideo; Miyasaka, Motomaro; Tanizaki, Yoshio; Yanagisawa, Nobuo; Sugishita, Morihiro.


    We reported 7 patients with left thalamic hemorrhage in the chronic stage (from 1.5 months to 4.5 months), and described language disorders examined by Western Aphasia Battery (WAB) and measured cerebral blood flow by single photon emission CT. Examination of language by WAB revealed 4 aphasics out of 7 cases, and 3 patients had no language deficit. The patient with Wernicke's aphasia showed low density area only in the left posterior thalamus in X-ray CT, and revealed severe low blood flow area extending to left temporal lobe in emission CT. In the case with transcortical sensory aphasia, although X-ray CT showed no obvious low density area, emission CT revealed moderate low flow area in watershed area that involved the territory between posterior cerebral and middle cerebral arteries in the left temporooccipital region in addition to low blood flow at the left thalamus. In one of the two patients classified as anomic aphasia, whose score of repetition (8.4) was higher than that of comprehension (7.4), emission CT showed slight low flow area at the temporo-occipital region similarly as the case with transcortical sensory aphasia. In another case with anomic aphasia, scored 9 on both fluensy and comprehension subtests and 10 on repetition, there was wide low density area all over the left thalamus and midline shift to the right in X-ray CT, and emission CT showed severe low blood flow in the same region spreading widely toward the cerebral surface. On the other hand, in all of the 3 patients without aphasia, emission CT showed low flow region restricted to the left thalamus. (J.P.N.)

  6. Determination of left ventricular heart volume by fast MRI in breath-hold technique: how different are quantitative ventricular angiography, quantitative MRI, and visual echocardiography?; Linksventrikulaere Herzvoluminabestimmung mittels schneller MRT in Atemanhaltetechnik: Wie unterschiedlich sind quantitativer Herzkatheter, quantitativer MRT und visuelle Echokardiographie?

    Energy Technology Data Exchange (ETDEWEB)

    Rominger, M.B.; Bachmann, G.F. [Giessen Univ. (Germany). Diagnostische Radiologie; Kerckhoff-Klinik GmbH, Bad Nauheim (Germany). Projektgruppe Magnetresonanztomographie; Pabst, W. [Giessen Univ. (Germany). Inst. fuer Medizinische Informatik; Ricken, W.W. [Kerckhoff-Klinik GmbH, Bad Nauheim (Germany). Projektgruppe Magnetresonanztomographie; Dinkel, H.P.; Rau, W.S. [Giessen Univ. (Germany). Diagnostische Radiologie


    Goal: Comparison of fast MRI, echocardiography (Echo), and ventricular angiography (Cath) in the assessment of left ventricular global function. Methods: Fast MRI in short axis plane, biplane Cath, and 2D Echo were performed in 62 patients [35 coronary artery diseases, 16 acquired valvular diseases (VD), 9 dilated cardiomyopathies (DCM), 1 congenital heart disease and 1 heart transplantation]. Enddiastolic (EDV), endsystolic (ESV), stroke volumes (SV), cardiac output (CO), and ejection fraction (EF) were compared in MRI and Cath. EF was visually estimated in 2D Echo by an experienced observer. Results: In comparison to MRI, Cath overestimated EF by 8.4%, and Echo underestimated EF by 5.6%. The limits of agreement between MRI and Cath in EF were {+-}23.8%, between MRI and Echo {+-}18%, and between Echo and Cath {+-}19.4%. Significant differences were found between Cath and MRI in EDV, SV, and CO, but not for ESV. The best agreement in EF was found in the group with DCM, the worst in the group with VD. Conclusion: Important systemic and random errors were found in the comparison of MRI, Echo, and Cath. For therapy decision and follow-up, the methods should not be exchanged unscrupulously. (orig.) [German] Ziel: Methodenvergleich von schneller Magnetresonanztomographie (MRT), Echokardiographie (Echo) und Herzkatheter (HK) in der Bestimmung linksventrikulaerer globaler Funktionsparameter. Material und Methoden: Bei 62 Patienten (35 koronare Herzerkrankungen, 16 Herzklappenvitien (KV), 9 idiopathische dilatative Kardiomyopathien (DCM), 1 kongenitale Herzerkrankung und 1 Herzktransplantation) wurde ein Methodenvergleich zwischen schneller Cine MRT im Kurzachsenschnitt, biplanarem HK und 2D Echo durchgefuehrt. Verglichen wurden in MRT und HK linksventrikulaeres enddiastolisches (EDV) und endsystolisches Volumen (ESV), Schlagvolumen (SV), Herzzeitvolumen (HZV) und Ejektionsfraktion (EF). In der Echo wurde die EF visuell durch einen erfahrenen Untersucher bestimmt

  7. Dissociation of response variability from firing rate effects in frontal eye field neurons during visual stimulation, working memory, and attention. (United States)

    Chang, Mindy H; Armstrong, Katherine M; Moore, Tirin


    Recent studies suggest that trial-to-trial variability of neuronal spiking responses may provide important information about behavioral state. Observed changes in variability during sensory stimulation, attention, motor preparation, and visual discrimination suggest that variability may reflect the engagement of neurons in a behavioral task. We examined changes in spiking variability of frontal eye field (FEF) neurons in a change detection task requiring monkeys to remember a visually cued location and direct attention to that location while ignoring distracters elsewhere. In this task, the firing rates (FRs) of FEF neurons not only continuously reflect the location of the remembered cue and select targets, but also predict detection performance on a trial-by-trial basis. Changes in FEF response variability, as measured by the Fano factor (FF), showed clear dissociations from changes in FR. The FF declined in response to visual stimulation at all tested locations, even in the opposite hemifield, indicating much broader spatial tuning of the FF compared with the FR. Furthermore, despite robust spatial modulation of the FR throughout all epochs of the task, spatial tuning of the FF did not persist throughout the delay period, nor did it show attentional modulation. These results indicate that changes in variability, at least in the FEF, are most effectively driven by visual stimulation, while behavioral engagement is not sufficient. Instead, changes in variability may reflect shifts in the balance between feedforward and recurrent sources of excitatory drive.

  8. Visual art and visual perception


    Koenderink, Jan J.


    Visual art and visual perception ‘Visual art’ has become a minor cul-de-sac orthogonal to THE ART of the museum directors and billionaire collectors. THE ART is conceptual, instead of visual. Among its cherished items are the tins of artist’s shit (Piero Manzoni, 1961, Merda d’Artista) “worth their weight in gold”. I perceive a metabletic (van den Berg, 1956) parallel to philosophy transforming itself into speculative logic games, and psychology going cognitive by freeing itself from phenomen...

  9. Visual Education

    DEFF Research Database (Denmark)

    Buhl, Mie; Flensborg, Ingelise


    The intrinsic breadth of various types of images creates new possibilities and challenges for visual education. The digital media have moved the boundaries between images and other kinds of modalities (e.g. writing, speech and sound) and have augmented the possibilities for integrating the functi......The intrinsic breadth of various types of images creates new possibilities and challenges for visual education. The digital media have moved the boundaries between images and other kinds of modalities (e.g. writing, speech and sound) and have augmented the possibilities for integrating...... to emerge in the interlocutory space of a global visual repertoire and diverse local interpretations. The two perspectives represent challenges for future visual education which require visual competences, not only within the arts but also within the subjects of natural sciences, social sciences, languages...

  10. Auditory motion capturing ambiguous visual motion

    Directory of Open Access Journals (Sweden)

    Arjen eAlink


    Full Text Available In this study, it is demonstrated that moving sounds have an effect on the direction in which one sees visual stimuli move. During the main experiment sounds were presented consecutively at four speaker locations inducing left- or rightwards auditory apparent motion. On the path of auditory apparent motion, visual apparent motion stimuli were presented with a high degree of directional ambiguity. The main outcome of this experiment is that our participants perceived visual apparent motion stimuli that were ambiguous (equally likely to be perceived as moving left- or rightwards more often as moving in the same direction than in the opposite direction of auditory apparent motion. During the control experiment we replicated this finding and found no effect of sound motion direction on eye movements. This indicates that auditory motion can capture our visual motion percept when visual motion direction is insufficiently determinate without affecting eye movements.

  11. Famous People Knowledge and the Right and Left Temporal Lobes (United States)

    Snowden, Julie S.; Thompson, Jennifer C.; Neary, David


    It is generally accepted that the anterior temporal lobes support knowledge of famous people. The specific roles of the right and left temporal lobe remain a subject of debate, with some studies suggesting differential roles based on modality (visual versus verbal information) and others category (person knowledge versus general semantics). The present study re-examined performance of semantic dementia patients with predominantly right and predominantly left temporal lobe atrophy on famous face, famous name and general semantic tasks, with the specific aim of testing the hypothesis that the right temporal lobe has a privileged role for person knowledge and the left temporal lobe for general semantic knowledge. Comparisons of performance rankings across tasks showed no evidence to support this hypothesis. By contrast, there was robust evidence from naming, identification and familiarity measures for modality effects: right-sided atrophy being associated with relatively greater impairment for faces and visual tasks and left-sided atrophy for names and verbal tasks. A double dissociation in test scores in two patients reinforced these findings. The data present a challenge for the influential ‘semantic hub’ model, which views the anterior temporal lobes as an area of convergence in which semantic information is represented in amodal form. PMID:22207421

  12. Visual cognition. (United States)

    Cavanagh, Patrick


    Visual cognition, high-level vision, mid-level vision and top-down processing all refer to decision-based scene analyses that combine prior knowledge with retinal input to generate representations. The label "visual cognition" is little used at present, but research and experiments on mid- and high-level, inference-based vision have flourished, becoming in the 21st century a significant, if often understated part, of current vision research. How does visual cognition work? What are its moving parts? This paper reviews the origins and architecture of visual cognition and briefly describes some work in the areas of routines, attention, surfaces, objects, and events (motion, causality, and agency). Most vision scientists avoid being too explicit when presenting concepts about visual cognition, having learned that explicit models invite easy criticism. What we see in the literature is ample evidence for visual cognition, but few or only cautious attempts to detail how it might work. This is the great unfinished business of vision research: at some point we will be done with characterizing how the visual system measures the world and we will have to return to the question of how vision constructs models of objects, surfaces, scenes, and events. Copyright © 2011 Elsevier Ltd. All rights reserved.

  13. Markers of preparatory attention predict visual short-term memory performance. (United States)

    Murray, Alexandra M; Nobre, Anna C; Stokes, Mark G


    Visual short-term memory (VSTM) is limited in capacity. Therefore, it is important to encode only visual information that is most likely to be relevant to behaviour. Here we asked which aspects of selective biasing of VSTM encoding predict subsequent memory-based performance. We measured EEG during a selective VSTM encoding task, in which we varied parametrically the memory load and the precision of recall required to compare a remembered item to a subsequent probe item. On half the trials, a spatial cue indicated that participants only needed to encode items from one hemifield. We observed a typical sequence of markers of anticipatory spatial attention: early attention directing negativity (EDAN), anterior attention directing negativity (ADAN), late directing attention positivity (LDAP); as well as of VSTM maintenance: contralateral delay activity (CDA). We found that individual differences in preparatory brain activity (EDAN/ADAN) predicted cue-related changes in recall accuracy, indexed by memory-probe discrimination sensitivity (d'). Importantly, our parametric manipulation of memory-probe similarity also allowed us to model the behavioural data for each participant, providing estimates for the quality of the memory representation and the probability that an item could be retrieved. We found that selective encoding primarily increased the probability of accurate memory recall; that ERP markers of preparatory attention predicted the cue-related changes in recall probability. Copyright © 2011. Published by Elsevier Ltd.

  14. Left Activism, Succour and Selfhood

    DEFF Research Database (Denmark)

    Hughes, Celia Penelope


    an interchange of motherhood, domesticity, far-left politics, and close female friendship. The article will show how the women's epistolary friendship offers intimate insight into female self-fashioning at a breakthrough social and political moment in 1970s Britain. As they reflected on some of the key political...

  15. Organ visualization

    International Nuclear Information System (INIS)


    The advantages of selenium-75-labelled cholesterol derivatives for the visualization of the adren in nuclear medicine are outlined. Selenium-75 is a sole gamma emitter; its chemical preparation is described

  16. Multifocal Visual Evoked Potential in Eyes With Temporal Hemianopia From Chiasmal Compression: Correlation With Standard Automated Perimetry and OCT Findings. (United States)

    Sousa, Rafael M; Oyamada, Maria K; Cunha, Leonardo P; Monteiro, Mário L R


    To verify whether multifocal visual evoked potential (mfVEP) can differentiate eyes with temporal hemianopia due to chiasmal compression from healthy controls. To assess the relationship between mfVEP, standard automated perimetry (SAP), and Fourier domain-optical coherence tomography (FD-OCT) macular and peripapillary retinal nerve fiber layer (RNFL) thickness measurements. Twenty-seven eyes with permanent temporal visual field (VF) defects from chiasmal compression on SAP and 43 eyes of healthy controls were submitted to mfVEP and FD-OCT scanning. Multifocal visual evoked potential was elicited using a stimulus pattern of 60 sectors and the responses were averaged for the four quadrants and two hemifields. Optical coherence tomography macular measurements were averaged in quadrants and halves, while peripapillary RNFL thickness was averaged in four sectors around the disc. Visual field loss was estimated in four quadrants and each half of the 24-2 strategy test points. Multifocal visual evoked potential measurements in the two groups were compared using generalized estimated equations, and the correlations between mfVEP, VF, and OCT findings were quantified. Multifocal visual evoked potential-measured temporal P1 and N2 amplitudes were significantly smaller in patients than in controls. No significant difference in amplitude was observed for nasal parameters. A significant correlation was found between mfVEP amplitudes and temporal VF loss, and between mfVEP amplitudes and the corresponding OCT-measured macular and RNFL thickness parameters. Multifocal visual evoked potential amplitude parameters were able to differentiate eyes with temporal hemianopia from controls and were significantly correlated with VF and OCT findings, suggesting mfVEP is a useful tool for the detection of visual abnormalities in patients with chiasmal compression.

  17. Both dog and human faces are explored abnormally by young children with autism spectrum disorders. (United States)

    Guillon, Quentin; Hadjikhani, Nouchine; Baduel, Sophie; Kruck, Jeanne; Arnaud, Mado; Rogé, Bernadette


    When looking at faces, typical individuals tend to have a right hemispheric bias manifested by a tendency to look first toward the left visual hemifield. Here, we tested for the presence of this bias in young children with autism spectrum disorders (ASD) for both human and dog faces. We show that children with ASD do not show a left visual hemifield (right hemispheric) bias for human faces. In addition, we show that this effect extends to faces of dogs, suggesting that the absence of bias is not specific to human faces, but applies to all faces with the first-order configuration, pointing to an anomaly at an early stage of visual analysis of faces. The lack of right hemispheric dominance for face processing may reflect a more general disorder of cerebral specialization of social functions in ASD.

  18. Left ventricular diastolic performance of left ventricular hypertrophy

    Energy Technology Data Exchange (ETDEWEB)

    Ikezono, Tohru; Ozaki, Masaharu; Yamagishi, Takashi; Shimizu, Tatsuro; Furutani, Yuji; Kusukawa, Reizo


    To study left ventricular diastolic performance in different forms of left ventricular hypertrophy, ECG gated cardiac blood pool scan was performed in 11 patients with hypertrophic nonobstructive cardiomyopathy (HCM) and in 19 patients with hypertension (HT), and left ventricular volume curve (LVVC) was analyzed and compared with those of 13 normal subjects (N). Ejection fraction (EF) and early filling volume ratio (the ratio of volume increment of 100 msec later than the zero point in the first derivative of LVVC to the end diastolic volume) (%EFV) were computed from LVVC. Peak ejection rate (PER) and peak filling rate (PFR) were obtained from the first derivative of LVVC. Peak ejection acceleration (PEA) and peak filling acceleration (PFA) were calculated from the second derivative of LVVC. EF, PER and PEA did not show any difference between these 3 groups. PFR was lower in HT (2.6 +- 0.5) compared with those in HCM (3.0 +- 0.5) (p < 0.05) and in N (3.4 +- 0.5) (p < 0.001), but the %EFV in HCM (4.9 +- 1.8) was lower than those in HT (6.9 +- 1.9) (p < 0.01) and in N (11.4 +- 1.4) (p < 0.001). Moreover, PFA in HCM (27.9 +- 7.2) was increased than those in HT (20.2 +- 5.4) (p < 0.01) with no differences between HCM and N (29.4 +- 8.1). Significant correlation was observed between PFR and PFA (Y = 0.06X + 1.4. r = 0.856. p < 0.001). These result indicate that, in HCM, reduced increase in early left ventricular volume is compensated by a greater filling acceleration. In contrast, there is no compensation by filling acceleration in HT.

  19. Ultrasound diagnosis of pulmonary sling with proximal stenosis of left pulmonary artery and patent arterial duct

    Directory of Open Access Journals (Sweden)

    Wojciech Mądry


    Full Text Available Authors discuss methods of echocardiographic diagnosis of the pulmonary sling with stenosis and hypoplasia of the left pulmonary artery and patent arterial duct with massive left‑to‑right shunt, based on a case of the newborn with resistant to treatment heart failure, with initial diagnosis of patent ductus arteriosus, referred to surgical treatment. The optimal echocardiographic views permitting establish diagnosis of the pulmonary sling were suggested. The special attention was paid to high parasternal and suprasternal views visualizing vessels of the upper mediastinum as well as characteristic differences between the normal and pathologic picture. The typical features of the echocardiogram suggesting pulmonary sling, like the lack of the left pulmonary artery in its expected position, and the abnormal branching pattern of the right pulmonary artery were indicated. The greatest diagnostic difficulties in visualization of the abnormal route of the left pulmonary artery were related to the presence of air‑containing tissues, like lungs and central airways between the ultrasound probe and area of interest. The other was the masking influence of the large patent arterial duct, that may mimic the left pulmonary artery arising from the pulmonary trunk. The other entities requiring differentiation with sling, like aplasia of the left lung, the direct or indirect aortic origin of the left pulmonary artery, were discussed. The role of other visualization technics, like computed 3D tomography, and magnetic nuclear resonance, as well as direct visualization of central airways with bronchoscopy in establishing precise diagnosis were stressed.

  20. The left fusiform gyrus hosts trisensory representations of manipulable objects

    DEFF Research Database (Denmark)

    Kassuba, Tanja; Klinge, Corinna; Hölig, Cordula


    During object manipulation the brain integrates the visual, auditory, and haptic experience of an object into a unified percept. Previous brain imaging studies have implicated for instance the dorsal part of the lateral occipital complex in visuo-tactile and the posterior superior temporal sulcus....... In the first experiment, we identified brain regions which were consistently activated by unimodal visual, auditory, and haptic processing of manipulable objects relative to non-object control stimuli presented in the same modality. In the second experiment, we assessed regional brain activations when...... participants had to match object-related information that was presented simultaneously in two or all three modalities. Only a well-defined region in left fusiform gyrus (FG) showed an object-specific activation during unisensory processing in the visual, auditory, and tactile modalities. The same region...

  1. Mean size estimation yields left-side bias: Role of attention on perceptual averaging. (United States)

    Li, Kuei-An; Yeh, Su-Ling


    The human visual system can estimate mean size of a set of items effectively; however, little is known about whether information on each visual field contributes equally to the mean size estimation. In this study, we examined whether a left-side bias (LSB)-perceptual judgment tends to depend more heavily on left visual field's inputs-affects mean size estimation. Participants were instructed to estimate the mean size of 16 spots. In half of the trials, the mean size of the spots on the left side was larger than that on the right side (the left-larger condition) and vice versa (the right-larger condition). Our results illustrated an LSB: A larger estimated mean size was found in the left-larger condition than in the right-larger condition (Experiment 1), and the LSB vanished when participants' attention was effectively cued to the right side (Experiment 2b). Furthermore, the magnitude of LSB increased with stimulus-onset asynchrony (SOA), when spots on the left side were presented earlier than the right side. In contrast, the LSB vanished and then induced a reversed effect with SOA when spots on the right side were presented earlier (Experiment 3). This study offers the first piece of evidence suggesting that LSB does have a significant influence on mean size estimation of a group of items, which is induced by a leftward attentional bias that enhances the prior entry effect on the left side.

  2. Visualizing water (United States)

    Baart, F.; van Gils, A.; Hagenaars, G.; Donchyts, G.; Eisemann, E.; van Velzen, J. W.


    A compelling visualization is captivating, beautiful and narrative. Here we show how melding the skills of computer graphics, art, statistics, and environmental modeling can be used to generate innovative, attractive and very informative visualizations. We focus on the topic of visualizing forecasts and measurements of water (water level, waves, currents, density, and salinity). For the field of computer graphics and arts, water is an important topic because it occurs in many natural scenes. For environmental modeling and statistics, water is an important topic because the water is essential for transport, a healthy environment, fruitful agriculture, and a safe environment.The different disciplines take different approaches to visualizing water. In computer graphics, one focusses on creating water as realistic looking as possible. The focus on realistic perception (versus the focus on the physical balance pursued by environmental scientists) resulted in fascinating renderings, as seen in recent games and movies. Visualization techniques for statistical results have benefited from the advancement in design and journalism, resulting in enthralling infographics. The field of environmental modeling has absorbed advances in contemporary cartography as seen in the latest interactive data-driven maps. We systematically review the design emerging types of water visualizations. The examples that we analyze range from dynamically animated forecasts, interactive paintings, infographics, modern cartography to web-based photorealistic rendering. By characterizing the intended audience, the design choices, the scales (e.g. time, space), and the explorability we provide a set of guidelines and genres. The unique contributions of the different fields show how the innovations in the current state of the art of water visualization have benefited from inter-disciplinary collaborations.

  3. Visual comparison for information visualization

    KAUST Repository

    Gleicher, M.


    Data analysis often involves the comparison of complex objects. With the ever increasing amounts and complexity of data, the demand for systems to help with these comparisons is also growing. Increasingly, information visualization tools support such comparisons explicitly, beyond simply allowing a viewer to examine each object individually. In this paper, we argue that the design of information visualizations of complex objects can, and should, be studied in general, that is independently of what those objects are. As a first step in developing this general understanding of comparison, we propose a general taxonomy of visual designs for comparison that groups designs into three basic categories, which can be combined. To clarify the taxonomy and validate its completeness, we provide a survey of work in information visualization related to comparison. Although we find a great diversity of systems and approaches, we see that all designs are assembled from the building blocks of juxtaposition, superposition and explicit encodings. This initial exploration shows the power of our model, and suggests future challenges in developing a general understanding of comparative visualization and facilitating the development of more comparative visualization tools. © The Author(s) 2011.

  4. Producing The New Regressive Left

    DEFF Research Database (Denmark)

    Crone, Christine

    This thesis is the first comprehensive research work conducted on the Beirut based TV station, an important representative of the post-2011 generation of Arab satellite news media. The launch of al-Mayadeen in June 2012 was closely linked to the political developments across the Arab world...... members, this thesis investigates a growing political trend and ideological discourse in the Arab world that I have called The New Regressive Left. On the premise that a media outlet can function as a forum for ideology production, the thesis argues that an analysis of this material can help to trace...... the contexture of The New Regressive Left. If the first part of the thesis lays out the theoretical approach and draws the contextual framework, through an exploration of the surrounding Arab media-and ideoscapes, the second part is an analytical investigation of the discourse that permeates the programmes aired...

  5. Greater Activity in the Frontal Cortex on Left Curves: A Vector-Based fNIRS Study of Left and Right Curve Driving.

    Directory of Open Access Journals (Sweden)

    Noriyuki Oka

    Full Text Available In the brain, the mechanisms of attention to the left and the right are known to be different. It is possible that brain activity when driving also differs with different horizontal road alignments (left or right curves, but little is known about this. We found driver brain activity to be different when driving on left and right curves, in an experiment using a large-scale driving simulator and functional near-infrared spectroscopy (fNIRS.The participants were fifteen healthy adults. We created a course simulating an expressway, comprising straight line driving and gentle left and right curves, and monitored the participants under driving conditions, in which they drove at a constant speed of 100 km/h, and under non-driving conditions, in which they simply watched the screen (visual task. Changes in hemoglobin concentrations were monitored at 48 channels including the prefrontal cortex, the premotor cortex, the primary motor cortex and the parietal cortex. From orthogonal vectors of changes in deoxyhemoglobin and changes in oxyhemoglobin, we calculated changes in cerebral oxygen exchange, reflecting neural activity, and statistically compared the resulting values from the right and left curve sections.Under driving conditions, there were no sites where cerebral oxygen exchange increased significantly more during right curves than during left curves (p > 0.05, but cerebral oxygen exchange increased significantly more during left curves (p < 0.05 in the right premotor cortex, the right frontal eye field and the bilateral prefrontal cortex. Under non-driving conditions, increases were significantly greater during left curves (p < 0.05 only in the right frontal eye field.Left curve driving was thus found to require more brain activity at multiple sites, suggesting that left curve driving may require more visual attention than right curve driving. The right frontal eye field was activated under both driving and non-driving conditions.

  6. Does visual working memory represent the predicted locations of future target objects? An event-related brain potential study. (United States)

    Grubert, Anna; Eimer, Martin


    During the maintenance of task-relevant objects in visual working memory, the contralateral delay activity (CDA) is elicited over the hemisphere opposite to the visual field where these objects are presented. The presence of this lateralised CDA component demonstrates the existence of position-dependent object representations in working memory. We employed a change detection task to investigate whether the represented object locations in visual working memory are shifted in preparation for the known location of upcoming comparison stimuli. On each trial, bilateral memory displays were followed after a delay period by bilateral test displays. Participants had to encode and maintain three visual objects on one side of the memory display, and to judge whether they were identical or different to three objects in the test display. Task-relevant memory and test stimuli were located in the same visual hemifield in the no-shift task, and on opposite sides in the horizontal shift task. CDA components of similar size were triggered contralateral to the memorized objects in both tasks. The absence of a polarity reversal of the CDA in the horizontal shift task demonstrated that there was no preparatory shift of memorized object location towards the side of the upcoming comparison stimuli. These results suggest that visual working memory represents the locations of visual objects during encoding, and that the matching of memorized and test objects at different locations is based on a comparison process that can bridge spatial translations between these objects. This article is part of a Special Issue entitled SI: Prediction and Attention. Copyright © 2014 Elsevier B.V. All rights reserved.

  7. Visual cognition

    Energy Technology Data Exchange (ETDEWEB)

    Pinker, S.


    This collection of research papers on visual cognition first appeared as a special issue of Cognition: International Journal of Cognitive Science. The study of visual cognition has seen enormous progress in the past decade, bringing important advances in our understanding of shape perception, visual imagery, and mental maps. Many of these discoveries are the result of converging investigations in different areas, such as cognitive and perceptual psychology, artificial intelligence, and neuropsychology. This volume is intended to highlight a sample of work at the cutting edge of this research area for the benefit of students and researchers in a variety of disciplines. The tutorial introduction that begins the volume is designed to help the nonspecialist reader bridge the gap between the contemporary research reported here and earlier textbook introductions or literature reviews.

  8. Information Visualization


    Díaz Baños, Carlos José; Andreasson, Erik


    Reasoning graphs are one of many ways to visualize information. It is very hard to understand certain type of information when it is presented in text or in tables with a huge amount of numbers. It is easier to present it graphically. People can have a general idea of the information and if it is necessary to see the details, it is possible to have a way to add more information to the graphical display. A graphical visualization is able to compress the information, which represented in text c...

  9. Visualizing Transformation

    DEFF Research Database (Denmark)

    Pedersen, Pia


    Transformation, defined as the step of extracting, arranging and simplifying data into visual form (M. Neurath, 1974), was developed in connection with ISOTYPE (International System Of TYpographic Picture Education) and might well be the most important legacy of Isotype to the field of graphic...... design. Recently transformation has attracted renewed interest because of the book The Transformer written by Robin Kinross and Marie Neurath. My on-going research project, summarized in this paper, identifies and depicts the essential principles of data visualization underlying the process...

  10. Systolic left ventricular function according to left ventricular concentricity and dilatation in hypertensive patients

    DEFF Research Database (Denmark)

    Bang, Casper; Gerdts, Eva; Aurigemma, Gerard P


    Left ventricular hypertrophy [LVH, high left ventricular mass (LVM)] is traditionally classified as concentric or eccentric based on left ventricular relative wall thickness. We evaluated left ventricular systolic function in a new four-group LVH classification based on left ventricular dilatation...

  11. Influence of auditory and audiovisual stimuli on the right-left prevalence effect

    DEFF Research Database (Denmark)

    Vu, Kim-Phuong L; Minakata, Katsumi; Ngo, Mary Kim


    compatibility. The right-left prevalence effects obtained with auditory stimuli are typically larger than that obtained with visual stimuli even though less attention should be demanded from the horizontal dimension in auditory processing. In the present study, we examined whether auditory or visual dominance...... vertical coding through use of the spatial-musical association of response codes (SMARC) effect, where pitch is coded in terms of height in space. In Experiment 1, we found a larger right-left prevalence effect for unimodal auditory than visual stimuli. Neutral, non-pitch coded, audiovisual stimuli did......When auditory stimuli are used in two-dimensional spatial compatibility tasks, where the stimulus and response configurations vary along the horizontal and vertical dimensions simultaneously, a right-left prevalence effect occurs in which horizontal compatibility dominates over vertical...

  12. Visualizing Series (United States)

    Unal, Hasan


    The importance of visualisation and multiple representations in mathematics has been stressed, especially in a context of problem solving. Hanna and Sidoli comment that "Diagrams and other visual representations have long been welcomed as heuristic accompaniments to proof, where they not only facilitate the understanding of theorems and their…

  13. Visual sedimentation. (United States)

    Huron, Samuel; Vuillemot, Romain; Fekete, Jean-Daniel


    We introduce Visual Sedimentation, a novel design metaphor for visualizing data streams directly inspired by the physical process of sedimentation. Visualizing data streams (e. g., Tweets, RSS, Emails) is challenging as incoming data arrive at unpredictable rates and have to remain readable. For data streams, clearly expressing chronological order while avoiding clutter, and keeping aging data visible, are important. The metaphor is drawn from the real-world sedimentation processes: objects fall due to gravity, and aggregate into strata over time. Inspired by this metaphor, data is visually depicted as falling objects using a force model to land on a surface, aggregating into strata over time. In this paper, we discuss how this metaphor addresses the specific challenge of smoothing the transition between incoming and aging data. We describe the metaphor's design space, a toolkit developed to facilitate its implementation, and example applications to a range of case studies. We then explore the generative capabilities of the design space through our toolkit. We finally illustrate creative extensions of the metaphor when applied to real streams of data.

  14. The role of the left Brodmann's areas 44 and 45 in reading words and pseudowords


    Heim, S.; Alter, K.; Ischebeck, A.; Amunts, K.; Eickhoff, S.; Mohlberg, H.; Zilles, K.; von Cramon, D.; Friederici, A.


    In this functional magnetic resonance imaging (fMRI) study, we investigated the influence of two task (lexical decision, LDT; phonological decision, PDT) on activation in Broca's region (left Brodmann's areas [BA] 44 and 45) during the processing of visually presented words and pseudowords. Reaction times were longer for pseudowords than words in LDT but did not differ in PDT. By combining the fMRI data with cytoarchitectonic anatomical probability maps, we demonstrated that the left BA 44 an...

  15. Rebuilding the US Health Left

    Directory of Open Access Journals (Sweden)

    Victor W. Sidel, MD


    Full Text Available With this issue Social Medicine begins a series of invited papers on the topic: “Rebuilding the US Health Left.” In this editorial we will outline our vision for this series. We undertake this project aware that our good friend and mentor, Dr. Walter Lear, one of the leading health activists of the 20th century, lies critically ill. Walter was the creator and custodian of the US Health Left Archives, a collection that is now with the University of Pennsylvania library. The collection reminds us of the important role left health care workers played in US history throughout the 20th century. They advocated for a national health program (Committee on the Costs of Medical Care, Physicians Forum, Medical Care Section/APHA, HealthPAC, Physicians for a National Health Program, National Physicians Alliance, provided international solidarity (American Soviet Medical Society, international brigades during the Spanish Civil War, Central American Solidarity Movement, Committee to Help Chilean Health Workers, Doctors for Global Health, traced the connections between disease and social class (Sigerist Circle, Spirit of 1848, APHA, fought for workers’ health (Councils for Occupational Safety and Health; Occupational Health and Safety Section, APHA participated in anti-war movements (Medical Committee for Human Rights, Physicians for Social Responsibility, International Physicians for the Prevention of Nuclear War, created new models of health care delivery (Health Cooperatives, Prepaid Health Maintenance Organizations, Community Health Centers, National Health Service Corps, Free Clinics, were central to the struggle for women’s rights (Planned Parenthood, Physicians for Reproductive Choice and Health, supported the civil rights movement both in medicine and in the broader society (National Medical Association, Medical Committee for Human Rights, played key roles in the movement for gay rights (ACT-UP, Gay & Lesbian Medical Association, Lesbian, Gay

  16. Visual PEF Reader - VIPER (United States)

    Luo, Victor; Khanampornpan, Teerapat; Boehmer, Rudy A.; Kim, Rachel Y.


    This software graphically displays all pertinent information from a Predicted Events File (PEF) using the Java Swing framework, which allows for multi-platform support. The PEF is hard to weed through when looking for specific information and it is a desire for the MRO (Mars Reconn aissance Orbiter) Mission Planning & Sequencing Team (MPST) to have a different way to visualize the data. This tool will provide the team with a visual way of reviewing and error-checking the sequence product. The front end of the tool contains much of the aesthetically appealing material for viewing. The time stamp is displayed in the top left corner, and highlighted details are displayed in the bottom left corner. The time bar stretches along the top of the window, and the rest of the space is allotted for blocks and step functions. A preferences window is used to control the layout of the sections along with the ability to choose color and size of the blocks. Double-clicking on a block will show information contained within the block. Zooming into a certain level will graphically display that information as an overlay on the block itself. Other functions include using hotkeys to navigate, an option to jump to a specific time, enabling a vertical line, and double-clicking to zoom in/out. The back end involves a configuration file that allows a more experienced user to pre-define the structure of a block, a single event, or a step function. The individual will have to determine what information is important within each block and what actually defines the beginning and end of a block. This gives the user much more flexibility in terms of what the tool is searching for. In addition to the configurability, all the settings in the preferences window are saved in the configuration file as well

  17. Visual rehabilitation of children with visual impairment

    NARCIS (Netherlands)

    Vervloed, M.P.J.; Janssen, N.M.; Knoors, H.E.T.


    Visual rehabilitation, consisting of visual stimulation and visual training, is a common practice in the education of children with visual impairments. Ferrell and Muir have stated that scientific research into the effects of visual stimulation and training is ambiguous and that therefore

  18. Visualizing Progress (United States)


    Reality Capture Technologies, Inc. is a spinoff company from Ames Research Center. Offering e-business solutions for optimizing management, design and production processes, RCT uses visual collaboration environments (VCEs) such as those used to prepare the Mars Pathfinder mission.The product, 4-D Reality Framework, allows multiple users from different locations to manage and share data. The insurance industry is one targeted commercial application for this technology.

  19. Cortical networks for visual self-recognition

    International Nuclear Information System (INIS)

    Sugiura, Motoaki


    This paper briefly reviews recent developments regarding the brain mechanisms of visual self-recognition. A special cognitive mechanism for visual self-recognition has been postulated based on behavioral and neuropsychological evidence, but its neural substrate remains controversial. Recent functional imaging studies suggest that multiple cortical mechanisms play self-specific roles during visual self-recognition, reconciling the existing controversy. Respective roles for the left occipitotemporal, right parietal, and frontal cortices in symbolic, visuospatial, and conceptual aspects of self-representation have been proposed. (author)

  20. Left-handed Children in Singapore. (United States)

    Gan, Linda


    Used teacher questionnaires to examine incidence of left-handedness in nearly 2,800 Singaporean children, racial differences in this left-handed population, and educational provisions in preschool and primary school. Findings indicated that 7.5% of preschoolers and 6.3% of primary children were left-handed, with a higher proportion being Chinese…

  1. The Left-Handed: "Their Sinister" History. (United States)

    Costas, Elaine Fowler

    The history of left-handedness can provide teachers and parents a better understanding of left-handed children and give those children more pride in their difference. No child should be made to feel that he or she is abnormal because of using the left hand, although some specific instruction for these students is necessary in handwriting. Many…

  2. Evolution of visual art with dopaminergic therapy. (United States)

    Walker, Ruth H


    A patient with right-side-predominant Parkinson's disease presented visual artwork which improved in resemblance to the model which he was copying with increasing doses of levodopa. I propose that increased dopaminergic replacement resulted in improved attention to detail, mediated by circuitry in the left hemisphere.

  3. Right Hemisphere Dominance in Visual Statistical Learning (United States)

    Roser, Matthew E.; Fiser, Jozsef; Aslin, Richard N.; Gazzaniga, Michael S.


    Several studies report a right hemisphere advantage for visuospatial integration and a left hemisphere advantage for inferring conceptual knowledge from patterns of covariation. The present study examined hemispheric asymmetry in the implicit learning of new visual feature combinations. A split-brain patient and normal control participants viewed…

  4. Conversations about Visual Arts: Facilitating Oral Language (United States)

    Chang, Ni; Cress, Susan


    Visual arts, such as drawings, are attractive to most young children. Marks left on paper by young children contain meaning. Although it is known that children's oral language could be enhanced through communication with adults, rarely is there a series of dialogues between adults and young children about their drawings. Often heard instead…

  5. Attentional reorienting triggers spatial asymmetries in a search task with cross-modal spatial cueing.

    Directory of Open Access Journals (Sweden)

    Rebecca E Paladini

    Full Text Available Cross-modal spatial cueing can affect performance in a visual search task. For example, search performance improves if a visual target and an auditory cue originate from the same spatial location, and it deteriorates if they originate from different locations. Moreover, it has recently been postulated that multisensory settings, i.e., experimental settings, in which critical stimuli are concurrently presented in different sensory modalities (e.g., visual and auditory, may trigger asymmetries in visuospatial attention. Thereby, a facilitation has been observed for visual stimuli presented in the right compared to the left visual space. However, it remains unclear whether auditory cueing of attention differentially affects search performance in the left and the right hemifields in audio-visual search tasks. The present study investigated whether spatial asymmetries would occur in a search task with cross-modal spatial cueing. Participants completed a visual search task that contained no auditory cues (i.e., unimodal visual condition, spatially congruent, spatially incongruent, and spatially non-informative auditory cues. To further assess participants' accuracy in localising the auditory cues, a unimodal auditory spatial localisation task was also administered. The results demonstrated no left/right asymmetries in the unimodal visual search condition. Both an additional incongruent, as well as a spatially non-informative, auditory cue resulted in lateral asymmetries. Thereby, search times were increased for targets presented in the left compared to the right hemifield. No such spatial asymmetry was observed in the congruent condition. However, participants' performance in the congruent condition was modulated by their tone localisation accuracy. The findings of the present study demonstrate that spatial asymmetries in multisensory processing depend on the validity of the cross-modal cues, and occur under specific attentional conditions, i.e., when

  6. Asymmetry in the Collision Judgments of People With Homonymous Field Defects and Left Hemispatial Neglect (United States)

    Houston, Kevin E.; Woods, Russell L.; Goldstein, Robert B.; Peli, Eli; Luo, Gang; Bowers, Alex R.


    Purpose. Although the impact of homonymous visual field defects (HFDs) on mobility has been investigated previously, the emphasis has been on obstacle detection. Relatively little is known about HFD patients' ability to judge collisions once an obstacle is detected. We investigated this using a walking simulator. Methods. Patients with HFDs (n = 29) and subjects with normal vision (NV; n = 21) were seated in front of a large screen on which a visual simulation of walking was displayed. They made collision judgments for a human figure that appeared for 1 second at lateral offsets from the virtual walking path. A perceived-collision threshold was calculated for right and left sides. Results. Symmetrical collision thresholds (same on left and right sides) were measured for participants with NV (n = 21), and right (n = 9) and left (n = 7) HFD without hemispatial neglect. Participants with left neglect (n = 10) showed significant asymmetry with thresholds smaller (compared to the NV group and other HFD groups) on the blind (P neglect group. Conclusions. Left neglect was associated with rightward asymmetry in collision judgments, which may cause collisions on the left side even when an obstacle is detected. These behaviors may represent the spatial misperceptions in body midline described previously in patients with left neglect. PMID:26120818

  7. EEG correlates of visual short-term memory in older age vary with adult lifespan cognitive development. (United States)

    Wiegand, Iris; Lauritzen, Martin J; Osler, Merete; Mortensen, Erik Lykke; Rostrup, Egill; Rask, Lene; Richard, Nelly; Horwitz, Anna; Benedek, Krisztina; Vangkilde, Signe; Petersen, Anders


    Visual short-term memory (vSTM) is a cognitive resource that declines with age. This study investigated whether electroencephalography (EEG) correlates of vSTM vary with cognitive development over individuals' lifespan. We measured vSTM performance and EEG in a lateralized whole-report task in a healthy birth cohort, whose cognitive function (intelligence quotient) was assessed in youth and late-middle age. Higher vSTM capacity (K; measured by Bundesen's theory of visual attention) was associated with higher amplitudes of the contralateral delay activity (CDA) and the central positivity (CP). In addition, rightward hemifield asymmetry of vSTM (K λ ) was associated with lower CDA amplitudes. Furthermore, more severe cognitive decline from young adulthood to late-middle age predicted higher CDA amplitudes, and the relationship between K and the CDA was less reliable in individuals who show higher levels of cognitive decline compared to individuals with preserved abilities. By contrast, there was no significant effect of lifespan cognitive changes on the CP or the relationship between behavioral measures of vSTM and the CP. Neither the CDA, nor the CP, nor the relationships between K or K λ and the event-related potentials were predicted by individuals' current cognitive status. Together, our findings indicate complex age-related changes in processes underlying behavioral and EEG measures of vSTM and suggest that the K-CDA relationship might be a marker of cognitive lifespan trajectories. Copyright © 2017 Elsevier Inc. All rights reserved.

  8. Assessment of the hemispheric lateralization of grapheme-color synesthesia with Stroop-type tests.

    Directory of Open Access Journals (Sweden)

    Mathieu J Ruiz

    Full Text Available Grapheme-color synesthesia, the idiosyncratic, arbitrary association of colors to letters or numbers, develops in childhood once reading is mastered. Because language processing is strongly left-lateralized in most individuals, we hypothesized that grapheme-color synesthesia could be left-lateralized as well. We used synesthetic versions of the Stroop test with colored letters and numbers presented either in the right or the left visual field of thirty-four synesthetes. Interference by synesthetic colors was stronger for stimuli in the right hemifield (first experiment, color naming task. Synesthetes were also faster in the right hemifield when naming the synesthetic color of graphemes (second experiment. Overall, the lateralization effect was 7 ms (the 95% confidence interval was [1.5 12] ms, a delay compatible with an additional callosal transfer for stimuli presented in the left hemifield. Though weak, this effect suggests that the association of synesthetic colors to graphemes may be preferentially processed in the left hemisphere. We speculate that this left-lateralization could be a landmark of synesthetic grapheme-color associations, if not found for color associations learnt by non-synesthete adults.

  9. Flavoured Dark Matter moving left (United States)

    Blanke, Monika; Das, Satrajit; Kast, Simon


    We investigate the phenomenology of a simplified model of flavoured Dark Matter (DM), with a dark fermionic flavour triplet coupling to the left-handed SU(2) L quark doublets via a scalar mediator. The DM-quark coupling matrix is assumed to constitute the only new source of flavour and CP violation, following the hypothesis of Dark Minimal Flavour Violation. We analyse the constraints from LHC searches, from meson mixing data in the K, D, and B d,s meson systems, from thermal DM freeze-out, and from direct detection experiments. Our combined analysis shows that while the experimental constraints are similar to the DMFV models with DM coupling to right-handed quarks, the multitude of couplings between DM and the SM quark sector resulting from the SU(2) L structure implies a richer phenomenology and significantly alters the resulting impact on the viable parameter space.

  10. Reading without the left ventral occipito-temporal cortex (United States)

    Seghier, Mohamed L.; Neufeld, Nicholas H.; Zeidman, Peter; Leff, Alex P.; Mechelli, Andrea; Nagendran, Arjuna; Riddoch, Jane M.; Humphreys, Glyn W.; Price, Cathy J.


    The left ventral occipito-temporal cortex (LvOT) is thought to be essential for the rapid parallel letter processing that is required for skilled reading. Here we investigate whether rapid written word identification in skilled readers can be supported by neural pathways that do not involve LvOT. Hypotheses were derived from a stroke patient who acquired dyslexia following extensive LvOT damage. The patient followed a reading trajectory typical of that associated with pure alexia, re-gaining the ability to read aloud many words with declining performance as the length of words increased. Using functional MRI and dynamic causal modelling (DCM), we found that, when short (three to five letter) familiar words were read successfully, visual inputs to the patient’s occipital cortex were connected to left motor and premotor regions via activity in a central part of the left superior temporal sulcus (STS). The patient analysis therefore implied a left hemisphere “reading-without-LvOT” pathway that involved STS. We then investigated whether the same reading-without-LvOT pathway could be identified in 29 skilled readers and whether there was inter-subject variability in the degree to which skilled reading engaged LvOT. We found that functional connectivity in the reading-without-LvOT pathway was strongest in individuals who had the weakest functional connectivity in the LvOT pathway. This observation validates the findings of our patient’s case study. Our findings highlight the contribution of a left hemisphere reading pathway that is activated during the rapid identification of short familiar written words, particularly when LvOT is not involved. Preservation and use of this pathway may explain how patients are still able to read short words accurately when LvOT has been damaged. PMID:23017598

  11. REcall Venice - Exploring disciplines of visual literacy through difficult heritage

    DEFF Research Database (Denmark)

    Tvedebrink, Tenna Doktor Olsen; Fisker, Anna Marie; Møller, Hans Ramsgaard


    , and archeologists question the role of architectural environments when dealing with war heritage. Today, there are still traces left from WWII in the European architectural environments, traces that by visual literacy represent unpleasant memories. However, these visual literacies have shaped our environment, yet......According to James Elkin visual literacy is interpreted as material representations, which communicate knowledge and create insight through their visual appearance. Based on the EU Cultural Heritage project REcall, we argue that visual literacy can also relate to interdisciplinary knowledge rooted......, slowly the collective memories are fading as the physical signs vanish....

  12. Visual search and line bisection in hemianopia: computational modelling of cortical compensatory mechanisms and comparison with hemineglect. (United States)

    Lanyon, Linda J; Barton, Jason J S


    Hemianopia patients have lost vision from the contralateral hemifield, but make behavioural adjustments to compensate for this field loss. As a result, their visual performance and behaviour contrast with those of hemineglect patients who fail to attend to objects contralateral to their lesion. These conditions differ in their ocular fixations and perceptual judgments. During visual search, hemianopic patients make more fixations in contralesional space while hemineglect patients make fewer. During line bisection, hemianopic patients fixate the contralesional line segment more and make a small contralesional bisection error, while hemineglect patients make few contralesional fixations and a larger ipsilesional bisection error. Hence, there is an attentional failure for contralesional space in hemineglect but a compensatory adaptation to attend more to the blind side in hemianopia. A challenge for models of visual attentional processes is to show how compensation is achieved in hemianopia, and why such processes are hindered or inaccessible in hemineglect. We used a neurophysiology-derived computational model to examine possible cortical compensatory processes in simulated hemianopia from a V1 lesion and compared results with those obtained with the same processes under conditions of simulated hemineglect from a parietal lesion. A spatial compensatory bias to increase attention contralesionally replicated hemianopic scanning patterns during visual search but not during line bisection. To reproduce the latter required a second process, an extrastriate lateral connectivity facilitating form completion into the blind field: this allowed accurate placement of fixations on contralesional stimuli and reproduced fixation patterns and the contralesional bisection error of hemianopia. Neither of these two cortical compensatory processes was effective in ameliorating the ipsilesional bias in the hemineglect model. Our results replicate normal and pathological patterns of

  13. Increased thallium lung uptake after exercise, a marker of left ventricular dysfunction

    International Nuclear Information System (INIS)

    Botsch, H.; Weidemann, H.; Zaharescu, A.


    Increased lung uptake of thallium-201 in patients during exercise stress testing has been found to be related to exercise-induced left ventricular dysfunction. In order to evaluate the lung uptakes as a parameter of left ventricular dysfunction we compared the lung uptake of thallium by visual analysis and by fitting a Lung/Heart-Ratio with the exercise-induced pulmonary capillary wedge pressure (PCP) in 73 patients with coronary heart disease. Assuming a PCP value of 23 mm Hg as the upper limit of normal left ventricular function, left ventricular dysfunction (L/H-ratio > 0.48) can be detected with a sensitivity of 84% and a specificity of 87%. Sensitivity and specificity of visual scan interpretation is 76 and 89%, respectively. Severe left ventricular dysfunction (PCP > 30 mm Hg) is detected by L/H-ratio in 96% and by visual interpretation in 93%. Evaluation of lung activity should be added to the routine interpretation of exercise thallium-201 myocardial imaging studies. (orig.) [de

  14. How information visualization novices construct visualizations. (United States)

    Grammel, Lars; Tory, Melanie; Storey, Margaret-Anne


    It remains challenging for information visualization novices to rapidly construct visualizations during exploratory data analysis. We conducted an exploratory laboratory study in which information visualization novices explored fictitious sales data by communicating visualization specifications to a human mediator, who rapidly constructed the visualizations using commercial visualization software. We found that three activities were central to the iterative visualization construction process: data attribute selection, visual template selection, and visual mapping specification. The major barriers faced by the participants were translating questions into data attributes, designing visual mappings, and interpreting the visualizations. Partial specification was common, and the participants used simple heuristics and preferred visualizations they were already familiar with, such as bar, line and pie charts. We derived abstract models from our observations that describe barriers in the data exploration process and uncovered how information visualization novices think about visualization specifications. Our findings support the need for tools that suggest potential visualizations and support iterative refinement, that provide explanations and help with learning, and that are tightly integrated into tool support for the overall visual analytics process.

  15. Mental Number Line Disruption in a Right-Neglect Patient after a Left-Hemisphere Stroke (United States)

    Pia, Lorenzo; Corazzini, Luca Latini; Folegatti, Alessia; Gindri, Patrizia; Cauda, Franco


    A right-neglect patient with focal left-hemisphere damage to the posterior superior parietal lobe was assessed for numerical knowledge and tested on the bisection of numerical intervals and visual lines. The semantic and verbal knowledge of numbers was preserved, whereas the performance in numerical tasks that strongly emphasize the visuo-spatial…

  16. Programming of left hand exploits task set but that of right hand depends on recent history. (United States)

    Tang, Rixin; Zhu, Hong


    There are many differences between the left hand and the right hand. But it is not clear if there is a difference in programming between left hand and right hand when the hands perform the same movement. In current study, we carried out two experiments to investigate whether the programming of two hands was equivalent or they exploited different strategies. In the first experiment, participants were required to use one hand to grasp an object with visual feedback or to point to the center of one object without visual feedback on alternate trials, or to grasp an object without visual feedback and to point the center of one object with visual feedback on alternating trials. They then performed the tasks with the other hand. The result was that previous pointing task affected current grasping when it was performed by the left hand, but not the right hand. In experiment 2, we studied if the programming of the left (or right) hand would be affected by the pointing task performed on the previous trial not only by the same hand, but also by the right (or left) hand. Participants pointed and grasped the objects alternately with two hands. The result was similar with Experiment 1, i.e., left-hand grasping was affected by right-hand pointing, whereas right-hand grasping was immune from the interference from left hand. Taken together, the results suggest that when open- and closed-loop trials are interleaved, motor programming of grasping with the right hand was affected by the nature of the online feedback on the previous trial only if it was a grasping trial, suggesting that the trial-to-trial transfer depends on sensorimotor memory and not on task set. In contrast, motor programming of grasping with the left hand can use information about the nature of the online feedback on the previous trial to specify the parameters of the movement, even when the type of movement that occurred was quite different (i.e., pointing) and was performed with the right hand. This suggests that

  17. Compression syndrome of the left renal vein

    Energy Technology Data Exchange (ETDEWEB)

    Justich, E.


    Severe compression of the left renal vein produces a pressure gradient between it and the inferior vena cava and results in changes in haemodynamics. The cause of the narrowing is usually the aorta, less commonly the superior mesenteric artery. Compression of the left renal vein may be responsible for a number of abnormalities such as primary varicoceles, primary varices of the ovarian, renal, pelvic and ureteric veins on the left, the more frequent occurrence of unilateral renal vein thrombosis on the left and the development of renovascular hypertension. One hundred and twenty-three selective phlebograms of the left renal vein and CT examinations of this structure in a further 87 patients acting as a control group were carried out. The significance of compression of the left renal vein as an aetiological factor in the development of the above mentioned abnormalities is discussed.

  18. New minimally invasive surgical approach for excision of left atrial myxoma. (United States)

    Spadaccio, Cristiano; Elkasrawy, Karim; Sutherland, Fraser W H


    A novel minimally invasive technique for left atrial myxoma surgery involving a combination of mini-sternotomy and restricted left atrial dome incision is described. Surgery is performed through a mini-J sternotomy at third intercostal space and a standard aorto-right atrial cannulation. Exposure of cardiac mass is obtained by a restricted incision of the left atrial dome which provides excellent view of the entire interatrial septum. Base of the tumor base is clearly visualized making the en-bloc excision extremely easy. Three cases were successfully treated with this technique and discharged with mild analgesic requirements. The limited invasiveness and the avoidance of wide incisions in the heart chambers are points of strength of this approach and allow to overcome the limitations of the currently used interatrial groove or transeptal approaches, as scarce visualization of the septum and site of tumor attachment and risk of conduction disturbances or traumatic injury to the mass.

  19. Multiplicativity of left centralizers forcing additivity

    Directory of Open Access Journals (Sweden)

    Mohammad Sayed Tammam El-Sayiad


    Full Text Available A multiplicative left centralizer for an associative ring R is a map satisfying T(xy = T\\(xy for all x,y in R. T is not assumed to be additive. In this paper we deal with the additivity of the multiplicative left centralizers in a ring which contains an idempotent element. Specially, we study additivity for multiplicative left centralizers in prime and semiprime rings which contain an idempotent element.

  20. Visualization rhetoric: framing effects in narrative visualization. (United States)

    Hullman, Jessica; Diakopoulos, Nicholas


    Narrative visualizations combine conventions of communicative and exploratory information visualization to convey an intended story. We demonstrate visualization rhetoric as an analytical framework for understanding how design techniques that prioritize particular interpretations in visualizations that "tell a story" can significantly affect end-user interpretation. We draw a parallel between narrative visualization interpretation and evidence from framing studies in political messaging, decision-making, and literary studies. Devices for understanding the rhetorical nature of narrative information visualizations are presented, informed by the rigorous application of concepts from critical theory, semiotics, journalism, and political theory. We draw attention to how design tactics represent additions or omissions of information at various levels-the data, visual representation, textual annotations, and interactivity-and how visualizations denote and connote phenomena with reference to unstated viewing conventions and codes. Classes of rhetorical techniques identified via a systematic analysis of recent narrative visualizations are presented, and characterized according to their rhetorical contribution to the visualization. We describe how designers and researchers can benefit from the potentially positive aspects of visualization rhetoric in designing engaging, layered narrative visualizations and how our framework can shed light on how a visualization design prioritizes specific interpretations. We identify areas where future inquiry into visualization rhetoric can improve understanding of visualization interpretation. © 2011 IEEE

  1. Anarchy, socialism and a Darwinian left. (United States)

    Clarke, Ellen


    In A Darwinian left Peter Singer aims to reconcile Darwinian theory with left wing politics, using evolutionary game theory and in particular a model proposed by Robert Axelrod, which shows that cooperation can be an evolutionarily successful strategy. In this paper I will show that whilst Axelrod's model can give support to a kind of left wing politics, it is not the kind that Singer himself envisages. In fact, it is shown that there are insurmountable problems for the idea of increasing Axelrodian cooperation within a welfare state. My surprising conclusion will be that a Darwinian left worthy of the name would be anarchistic.

  2. What is Beyond Right/Left?

    DEFF Research Database (Denmark)

    Dyrberg, Torben Bech


    The article looks at New Labour's move beyond right/left in the mid/late 1990s, which is an occasion to spell out the nature of right/left and what it means for democracy. In contrast to both defenders and critics of this move I argue in the first part that right/left is not an empty label bound up...... right/left. I argue that the new hegemonic orientation is that of front/back, which designs political renewal as a response to the social changes cutting across the outdated lines of contestation of partisan politics. The democratic problem of this move lies in squeezing politics between technocratic...

  3. Left atrial systolic force in hypertensive patients with left ventricular hypertrophy: the LIFE study

    DEFF Research Database (Denmark)

    Chinali, M.; Simone, G. de; Wachtell, K.


    In hypertensive patients without prevalent cardiovascular disease, enhanced left atrial systolic force is associated with left ventricular hypertrophy and increased preload. It also predicts cardiovascular events in a population with high prevalence of obesity. Relations between left atrial...... with larger left ventricular diameter and higher left ventricular mass index (both P hypertrophy was greater (84 vs. 64%; P ..., transmitral peak E velocities and peak A velocities; and lower E/A ratio (all P hypertrophy, but normal left ventricular chamber systolic function with increased...

  4. Visuokinesthetic perception of hand movement is mediated by cerebro-cerebellar interaction between the left cerebellum and right parietal cortex. (United States)

    Hagura, Nobuhiro; Oouchida, Yutaka; Aramaki, Yu; Okada, Tomohisa; Matsumura, Michikazu; Sadato, Norihiro; Naito, Eiichi


    Combination of visual and kinesthetic information is essential to perceive bodily movements. We conducted behavioral and functional magnetic resonance imaging experiments to investigate the neuronal correlates of visuokinesthetic combination in perception of hand movement. Participants experienced illusory flexion movement of their hand elicited by tendon vibration while they viewed video-recorded flexion (congruent: CONG) or extension (incongruent: INCONG) motions of their hand. The amount of illusory experience was graded by the visual velocities only when visual information regarding hand motion was concordant with kinesthetic information (CONG). The left posterolateral cerebellum was specifically recruited under the CONG, and this left cerebellar activation was consistent for both left and right hands. The left cerebellar activity reflected the participants' intensity of illusory hand movement under the CONG, and we further showed that coupling of activity between the left cerebellum and the "right" parietal cortex emerges during this visuokinesthetic combination/perception. The "left" cerebellum, working with the anatomically connected high-order bodily region of the "right" parietal cortex, participates in online combination of exteroceptive (vision) and interoceptive (kinesthesia) information to perceive hand movement. The cerebro-cerebellar interaction may underlie updating of one's "body image," when perceiving bodily movement from visual and kinesthetic information.

  5. Influence of slice thickness on the determination of left ventricular wall thickness and dimension by magnetic resonance imaging

    Energy Technology Data Exchange (ETDEWEB)

    Ohnishi, Shusaku; Fukui, Sugao; Atsumi, Chisato and others


    Wall thickness of the ventricular septum and left ventricle, and left ventricular cavity dimension were determined on magnetic resonance (MR) images with slices 5 mm and 10 mm in thickness. Subjects were 3 healthy volunteers and 7 patients with hypertension (4), hypertrophic cardiomyopathy (one) or valvular heart disease (2). In visualizing the cardiac structures such as left ventricular papillary muscle and right and left ventricles, 5 mm-thick images were better than 10 mm-thick images. Edges of ventricular septum and left ventricular wall were more clearly visualized on 5 mm-thick images than 10 mm-thick images. Two mm-thick MR images obtained from 2 patients yielded the most excellent visualization in end-systole, but failed to reveal cardiac structures in detail in end-diastole. Phantom studies revealed no significant differences in image quality of 10 mm and 5 mm in thickness in the axial view 80 degree to the long axis. In the axial view 45 degree to the long axis, 10 mm-thick images were inferior to 5 mm-thick images in detecting the edge of the septum and the left ventricular wall. These results indicate that the selection of slice thickness is one of the most important determinant factors in the measurement of left ventricular wall thickness and cavity dimension. (Namekawa, K).

  6. Effects of handedness on visual sensitivity in perihand space.

    Directory of Open Access Journals (Sweden)

    Nathalie Le Bigot

    Full Text Available Recent studies have shown that changes in visual processing in perihand space are limited to the area around the right hand, at least in right-handers. One explanation for these findings is that perception is altered at locations where action is more likely to occur. To test this notion, we asked both right- and left-handers to perform an unspeeded visual discrimination task under four hand-position configurations: Left hand, right hand, both hands, or no hands near the display. Compared to the no-hands (control condition, visual sensitivity (d' was higher in the dominant-hand condition for right-handers and higher in the dominant- as well as the non-dominant hand condition for left-handers. When both hands were near the display, sensitivity was similar to that in the dominant-hand condition for right-handers and to that in the non-dominant hand condition for left-handers. This shows that performance differed between the two handedness groups when their non-dominant hand was near the display (both alone and accompanied by their dominant hand. Thus, the pattern for left-handers did not correspond to a mirror image of the pattern for right-handers. In line with studies on bimanual action control, visual processing in perihand space seems to be determined by the different ways in which left- and right-handers use their hands.

  7. Visualizing Entropy (United States)

    Lechner, Joseph H.


    This report describes two classroom activities that help students visualize the abstract concept of entropy and apply the second law of thermodynamics to real situations. (i) A sealed "rainbow tube" contains six smaller vessels, each filled with a different brightly colored solution (low entropy). When the tube is inverted, the solutions mix together and react to form an amorphous precipitate (high entropy). The change from low entropy to high entropy is irreversible as long as the tube remains sealed. (ii) When U.S. currency is withdrawn from circulation, intact bills (low entropy) are shredded into small fragments (high entropy). Shredding is quick and easy; the reverse process is clearly nonspontaneous. It is theoretically possible, but it is time-consuming and energy-intensive, to reassemble one bill from a pile that contains fragments of hundreds of bills. We calculate the probability P of drawing pieces of only one specific bill from a mixture containing one pound of bills, each shredded into n fragments. This result can be related to Boltzmann's entropy formula S?=klnW.

  8. Left Paraduodenal Hernia: An Autopsy Case

    DEFF Research Database (Denmark)

    Omland, Silje Haukali; Hougen, Hans Petter


    We present a case of a left paraduodenal hernia diagnosed at autopsy. A left paraduodenal hernia is an internal hernia of congenital origin due to the abnormal rotation of the midgut during embryonic development. Internal hernias are a rare cause of intestinal obstruction, with the paraduodenal...

  9. Malignant phyllodes tumor of the left atrium

    Directory of Open Access Journals (Sweden)

    Anupam Bhambhani


    Full Text Available Metastatic tumors to the heart usually involve right sided chambers. We report a rare case of malignant phyllodes tumor of breast with metastatic involvement of left atrium occurring through direct invasion from mediastinal micro-metastasis and presenting as a left atrial mass causing arrhythmia.

  10. Left ventricular hypertrophy, geometric patterns and clinical ...

    African Journals Online (AJOL)

    Background: Left ventricular hypertrophy can be due to various reasons including hypertension. It constitutes an increased cardiovascular risk. Various left ventricular geometric patterns occur in hypertension and may affect the cardiovascular risk profile of hypertensive subjects. Methods: One hundred and eighty eight ...

  11. Leptogenesis with left-right domain walls

    Indian Academy of Sciences (India)

    the scale of left-right symmetry breaking. Keywords. Leptogenesis; baryogenesis; domain walls; left-right symmetry. PACS Nos 12.10.Dm; 98.80.Cq; 98.80.Ft. Explaining the observed baryon asymmetry of the Universe within the framework of gauge theories and the standard Big Bang cosmology remains an open problem.

  12. On establishing coreference in Left Dislocation constructions ...

    African Journals Online (AJOL)

    The phenomenon of left dislocation (LD) has received relatively little attention in the generative literature. In Government & Binding theory and early versions of Minimalist Syntax, the left-dislocated expression is conventionally taken to be base-generated in its sentence-initial surface position and the resumptive pronoun in ...

  13. A new clinical sign probably associated to left hemiplegia with left hemineglect syndrome: the crossed legs. (United States)

    Bazan, Rodrigo; Fernandes, Thiago; Braga, Gabriel; Luvizutto, Gustavo; Resende, Luiz


    To describe a new clinical sign associated with left unilateral neglect syndrome (UNS) in patients with ischemic stroke. Head computed tomography (CT) and National Institute of Health Stroke Scale were obtained in 150 patients with ischemic stroke. Those with right cerebral vascular lesions, left hemiplegia and right leg persistently crossed over the left were submitted to specific tests for UNS. The tests were also applied to 30 patients with right cerebral vascular lesions, left hemiplegia but without crossed legs. From 9 patients with persistent tendency to cross the right leg over the left, UNS was detected in 8. One patient died before the clinical tests were applied. Of the 30 patients without the crossed legs, 20 had normal clinical tests for UNS and 10 had minimal alterations, not sufficient for the diagnosis of UNS. The right leg crossed over the left may represent a new neurological semiotic sign associated with left hemiplegia and left UNS.

  14. Bayesian analysis of MEG visual evoked responses

    Energy Technology Data Exchange (ETDEWEB)

    Schmidt, D.M.; George, J.S.; Wood, C.C.


    The authors developed a method for analyzing neural electromagnetic data that allows probabilistic inferences to be drawn about regions of activation. The method involves the generation of a large number of possible solutions which both fir the data and prior expectations about the nature of probable solutions made explicit by a Bayesian formalism. In addition, they have introduced a model for the current distributions that produce MEG and (EEG) data that allows extended regions of activity, and can easily incorporate prior information such as anatomical constraints from MRI. To evaluate the feasibility and utility of the Bayesian approach with actual data, they analyzed MEG data from a visual evoked response experiment. They compared Bayesian analyses of MEG responses to visual stimuli in the left and right visual fields, in order to examine the sensitivity of the method to detect known features of human visual cortex organization. They also examined the changing pattern of cortical activation as a function of time.

  15. Computerized method of visual acuity testing: adaptation of the amblyopia treatment study visual acuity testing protocol. (United States)

    Moke, P S; Turpin, A H; Beck, R W; Holmes, J M; Repka, M X; Birch, E E; Hertle, R W; Kraker, R T; Miller, J M; Johnson, C A


    To report a computerized method for determining visual acuity in children using the Amblyopia Treatment Study visual acuity testing protocol. A computerized visual acuity tester was developed that uses a programmed handheld device that uses the Palm operating system (Palm, Inc, Santa Clara, California). The handheld device communicates with a personal computer running a Linux operating system and 17-inch monitor. At a test distance of 3 m, single letters can be displayed from 20/800 to 20/12. A C program on the handheld device runs the Amblyopia Treatment Study visual acuity testing protocol. Using this method, visual acuity was tested in both the right and left eyes, and then the testing was repeated in 156 children age 3 to 7 years at four clinical sites. Test-retest reliability was high (r =.92 and 0.95 for and right and left eyes, respectively), with 88% of right eye retests and 94% of left eye retests within 0.1 logarithm of minimal angle of resolution (logMAR) units of the initial test. The 95% confidence interval for an acuity score was calculated to be the score +/- 0.13 logMAR units. For a change between two acuity scores, the 95% confidence interval was the difference +/- 0.19 logMAR units. We have developed a computerized method for measurement of visual acuity. Automation of the Amblyopia Treatment Study visual acuity testing protocol is an effective method of testing visual acuity in children 3 to 7 years of age.


    Directory of Open Access Journals (Sweden)



    Full Text Available During early embryonic development, absorption of pulmonary venous network by the left primitive atrial chamber results in opening of four pulmonary veins which drain independently into its chamber. The extent of absorption and hence, the number of pulmon ary veins which open into the left atrium, may vary. Here we report a variation in the opening of the Left upper (superior pulmonary vein into the Left atrium. A total of six openings observed

  17. Visual neglect in posterior cortical atrophy

    Directory of Open Access Journals (Sweden)

    Andrade Katia


    Full Text Available Abstract Background In posterior cortical atrophy (PCA, there is a progressive impairment of high-level visual functions and parietal damage, which might predict the occurrence of visual neglect. However, neglect may pass undetected if not assessed with specific tests, and might therefore be underestimated in PCA. In this prospective study, we aimed at establishing the side, the frequency and the severity of visual neglect, visual extinction, and primary visual field defects in an unselected sample of PCA patients. Methods Twenty-four right-handed PCA patients underwent a standardized battery of neglect tests. Visual fields were examined clinically by the confrontation method. Results Sixteen of the 24 patients (66% had signs of visual neglect on at least one test, and fourteen (58% also had visual extinction or hemianopia. Five patients (21% had neither neglect nor visual field defects. As expected, left-sided neglect was more severe than right-sided neglect. However, right-sided neglect resulted more frequently in this population (29% than in previous studies on focal brain lesions. Conclusion When assessed with specific visuospatial tests, visual neglect is frequent in patients with PCA. Diagnosis of neglect is important because of its negative impact on daily activities. Clinicians should consider the routine use of neglect tests to screen patients with high-level visual deficits. The relatively high frequency of right-sided neglect in neurodegenerative patients supports the hypothesis that bilateral brain damage is necessary for right-sided neglect signs to occur, perhaps because of the presence in the right hemisphere of crucial structures whose damage contributes to neglect.

  18. [Visual art, creativity and dementia]. (United States)

    Serrano, C; Allegri, R F; Martelli, M; Taragano, F; Rinalli, P


    Visual art is an expression of neurological function and how it organizes and interprets perception. The art is predominantly in the right hemisphere, in contrast, the left side, have inhibitory effects on artistic expression. In normal subjects, inhibitory and excitatory mechanisms could interact in a complex harmony, reflecting a paradoxical functional facilitation. Brain diseases such as dementia could change this harmony and then, alter the artistic abilities. Evaluate the art expression in the degenerative diseases. Artistic abilities of 3 painters with degenerative diseases were assessment. Patient 1: A 83 - year old right handed female, diagnosis: Alzheimer's disease. Artistic description: low productivity, simplified versions of earlier and alteration of the visuospatial organization. Patient 2: A 78-year-old right handed female, diagnosis: Primary Progressive Aphasia (PPA); Artistic description: oversimplified drawings which maintaining overall spatial organization, without impair artistic skills. Patient 3: A 68 year-old right handed woman, diagnosis: Fronto-Temporal Dementia (FTD). Artistic description: Increased artistic activity, originality, freedom, utilization of intense colours with perseverative and repetitive copying of similar paintings of her own work. Visual art in Alzheimer's disease is a consequence of visuospatial and constructive disabilities. In contrast, the conservation of this cognitive functions and left asymmetrical involved, in FTD and PPA respectively, suggest artistic preservation, independently of the language injury. The disproportionate functional prevalence of the right over the left could lead to a release of novelty - seeking in art and can contribute to emergent creativity. These observations suggest an organization for art in the brain and proposed bases for further investigations in dementias.

  19. Unimodal and multimodal regions for logographic language processing in left ventral occipitotemporal cortex

    Directory of Open Access Journals (Sweden)

    Yuan eDeng


    Full Text Available The human neocortex appears to contain a dedicated visual word form area (VWFA and an adjacent multimodal (visual/auditory area. However, these conclusions are based on functional magnetic resonance imaging (fMRI of alphabetic language processing, languages that have clear grapheme-to-phoneme correspondence (GPC rules that make it difficult to disassociate visual-specific processing from form-to-sound mapping. In contrast, the Chinese language has no clear GPC rules. Therefore, the current study examined whether native Chinese readers also have the same VWFA and multimodal area. Two cross-modal tasks, phonological retrieval of visual words and orthographic retrieval of auditory words, were adopted. Different task requirements were also applied to explore how different levels of cognitive processing modulate activation of putative VWFA-like and multimodal-like regions. Results showed that the left occipitotemporal sulcus responded exclusively to visual inputs and an adjacent region, the left inferior temporal gyrus, showed comparable activation for both visual and auditory inputs. Surprisingly, processing levels did not significantly alter activation of these two regions. These findings indicated that there are both unimodal and multimodal word areas for non-alphabetic language reading, and that activity in these two word-specific regions are independent of task demands at the linguistic level.

  20. Cortical Visual Impairment (United States)

    ... Frequently Asked Questions Español Condiciones Chinese Conditions Cortical Visual Impairment En Español Read in Chinese What is cortical visual impairment? Cortical visual impairment (CVI) is a decreased ...

  1. The visual divide (United States)

    Maes, Alfons


    Climate change is a playground for visualization. Yet research and technological innovations in visual communication and data visualization do not account for a substantial part of the world's population: vulnerable audiences with low levels of literacy.

  2. Learning Visualizations by Analogy: Promoting Visual Literacy through Visualization Morphing. (United States)

    Ruchikachorn, Puripant; Mueller, Klaus


    We propose the concept of teaching (and learning) unfamiliar visualizations by analogy, that is, demonstrating an unfamiliar visualization method by linking it to another more familiar one, where the in-betweens are designed to bridge the gap of these two visualizations and explain the difference in a gradual manner. As opposed to a textual description, our morphing explains an unfamiliar visualization through purely visual means. We demonstrate our idea by ways of four visualization pair examples: data table and parallel coordinates, scatterplot matrix and hyperbox, linear chart and spiral chart, and hierarchical pie chart and treemap. The analogy is commutative i.e. any member of the pair can be the unfamiliar visualization. A series of studies showed that this new paradigm can be an effective teaching tool. The participants could understand the unfamiliar visualization methods in all of the four pairs either fully or at least significantly better after they observed or interacted with the transitions from the familiar counterpart. The four examples suggest how helpful visualization pairings be identified and they will hopefully inspire other visualization morphings and associated transition strategies to be identified.

  3. Dyslexia linked to talent: global visual-spatial ability. (United States)

    von Károlyi, Catya; Winner, Ellen; Gray, Wendy; Sherman, Gordon F


    Dyslexia has long been defined by deficit. Nevertheless, the view that visual-spatial talents accompany dyslexia has grown, due to reports of individuals with dyslexia who possess visual-spatial strengths, findings of elevated incidence of dyslexia in certain visual-spatial professions, and the hypothesis that left-hemisphere deficits accompany right-hemisphere strengths. Studies have reported superior, inferior, and average levels of visual-spatial abilities associated with dyslexia. In two investigations, we found an association between dyslexia and speed of recognition of impossible figures, a global visual-spatial task. This finding suggests that dyslexia is associated with a particular type of visual-spatial talent-enhanced ability to process visual-spatial information globally (holistically) rather than locally (part by part).

  4. A conditioned visual orientation requires the ellipsoid body in Drosophila. (United States)

    Guo, Chao; Du, Yifei; Yuan, Deliang; Li, Meixia; Gong, Haiyun; Gong, Zhefeng; Liu, Li


    Orientation, the spatial organization of animal behavior, is an essential faculty of animals. Bacteria and lower animals such as insects exhibit taxis, innate orientation behavior, directly toward or away from a directional cue. Organisms can also orient themselves at a specific angle relative to the cues. In this study, using Drosophila as a model system, we established a visual orientation conditioning paradigm based on a flight simulator in which a stationary flying fly could control the rotation of a visual object. By coupling aversive heat shocks to a fly's orientation toward one side of the visual object, we found that the fly could be conditioned to orientate toward the left or right side of the frontal visual object and retain this conditioned visual orientation. The lower and upper visual fields have different roles in conditioned visual orientation. Transfer experiments showed that conditioned visual orientation could generalize between visual targets of different sizes, compactness, or vertical positions, but not of contour orientation. Rut-Type I adenylyl cyclase and Dnc-phosphodiesterase were dispensable for visual orientation conditioning. Normal activity and scb signaling in R3/R4d neurons of the ellipsoid body were required for visual orientation conditioning. Our studies established a visual orientation conditioning paradigm and examined the behavioral properties and neural circuitry of visual orientation, an important component of the insect's spatial navigation. © 2014 Guo et al.; Published by Cold Spring Harbor Laboratory Press.

  5. Interrelationships between visual-motor integration, visual ...

    African Journals Online (AJOL)

    The Developmental Test of Visual-Motor Integration (4th ed.) (VMI), was used to evaluate visual skills, while the Test of Gross Motor Development-2 evaluated six object control skills. There was a statistical significant (p≤0.01) association between VMI, two object control skills and total score for object control skills. Visual ...

  6. [Difficulties in face identification after lesion in the left hemisphere]. (United States)

    Verstichel, P; Chia, L


    A 82 year-old right-handed man, without any intellectual impairment, suffered from an acute neurological deficit consisting in letter-by-letter reading, right superior quadrant hemianopia with achromatopia in the lower quadrant, and anomia. Cerebral MRI showed an infarct involving the ventral structures of the left hemisphere sparing the splenium of the corpus callosum and the thalamus. Neuropsychological examination revealed that the patient easily identified the objects, the animals and the famous places he could not name: his comments attested normal visual recognition. Conversely, when he was presented with famous faces, he always had a strong feeling of familiarity, but could not provide accurate information about the corresponding individual. Biographic information about personalities was not impaired in the semantic-biographic store, because it could be accessed from the names. Activation of face recognition units (where the visual description provided by the structural encoding and the stored sets of descriptions of familiar faces are compared), was effective, since the patient could distinguish famous faces from unknown ones. In a modular-sequential model of face recognition, this deficit is interpreted as a disconnection between face recognition units and person identity nodes (which are considered to contain semantic-biographic information about individuals). This kind of disturbance differs from classic prosopagnosia in which, characteristically, the patients are unable to experience a feeling of familiarity when viewing famous faces, and to perform a categorization between famous and unknown faces. Right hemisphere has a preponderant role in structural analysis of faces and in activation of face recognition units. The integrity of this hemisphere in this patient could explain the preservation of these two steps of processing. Left-hemisphere specific function in facial recognition enabled access to semantic-biographic store in a conscious, verbal and

  7. Social aspects of left-handedness

    Directory of Open Access Journals (Sweden)

    Belojević Goran


    Full Text Available Throughout human history left-handedness has been considered as sinful. It has been associated with the devil, weakness, female gender, unhealthiness, evil, something that has to be turned to a “good” - right side by force. Left-handedness is being more and more acceptable at rational level, but in everyday life it is still considered to be unusual if someone writes with the left hand. Lessening of the number of lefthanders is associated with ageing. There are about 13% lefthanders among people in twenties and less than 1% lefthanders among those in eighties. This finding may be explaned with more pronounced socio-cultural pressure on left-handed people in the past, compared to nowadays. On the other hand, this may also support the hypothesis about a reduced life span of lefthanded people. With cross-exercising of left-handedness, certain typical characteristics and behavioral patterns appear in these people. This was a sort of provoked behavior and an attack on the integrity of an emotional attitude toward oneself. Stuttering may also appear as a consequence of unsuccessful cross-exercising of left-handedness. The hypothesis about left-handedness as an advantage is supported with the reports about relatively more lefthanders in some specific groups such as: mathematicians, sculptors, architects, painters, musicians, actors, tennis players, as well as famous army commanders and rulers.

  8. Left ventricular performance during triggered left ventricular pacing in patients with cardiac resynchronization therapy and left bundle branch block

    DEFF Research Database (Denmark)

    Witt, Christoffer Tobias; Kronborg, Mads Brix; Nohr, Ellen Aagaard


    PURPOSE: To assess the acute effect of triggered left ventricular pacing (tLVp) on left ventricular performance and contraction pattern in patients with heart failure, left bundle branch block (LBBB), and cardiac resynchronization therapy (CRT). METHODS: Twenty-three patients with pre-implant QRS...... complex >150 ms, QRS complex narrowing under CRT, and sinus rhythm were included ≥3 months after CRT implantation. Echocardiographic assessment of left ventricular ejection fraction (LVEF), global peak systolic longitudinal strain (GLS), and contraction pattern by 2D strain was performed during intrinsic......V pacing. CONCLUSIONS: The acute effect of tLVp on LV systolic function and contraction pattern is significantly lower than the effect of BiV pacing and not different from intrinsic conduction in patients with LBBB and CRT....

  9. [Vectorcardiographic manifestations of left intraventricular conduction disorders]. (United States)

    de Micheli, A; Medrano, G A


    Both, the vectorcardiographic changes produced by the various degrees of left bundle branch block and these observed with the different types of left distal block, are described. When a "wave jumping" phenomenon exists, the vectorcardiographic changes are more characteristic in the horizontal plane than in the frontal plane and can be interpreted satisfactorily in basis of the ventricular activation sequence. The normal counterclockwise rotation of the horizontal vectorcardiogram persists in the presence of left bundle branch block of slight and moderate degrees, since the electromotive forces of the free left ventricular wall are still predominant. In the majority of intermediate degree blocks, the middle portion of the RH loop develops with a clockwise rotation and general aspect with a clockwise rotation and the general aspect of the ventricular loop resembles an eight figure. This is due to the electromotive forces originated by the delayed depolarization of the left septal mass that starts to predominate. With advanced degrees of block, the largest portion of the RH loop shows a clockwise rotation, as well as marked notchings and slurrings. The initial anterior portion of the horizontal vectorcardiogram does not disappear, but is situated to the left of the anterior-posterior axis with a counterclockwise rotation (first right septal vector). Otherwise, the direct electrical sign of left distal block emphasized: evidence of delayed activation in a limited zone of the homolateral ventricle. This local delay gives rise to an asynchronism of the activation phenomenon between the upper and lower regions of the ventricle. The diagnosis of left bifascicular block is based essentially on the evidence of unequal delay of the activation sequence in the basal regions and in the inferior ones of the homolateral ventricle and also on the frequent persistence of the first left septal vector.

  10. Structural changes in left fusiform areas and associated fiber connections in children with abacus training: Evidence from morphometry and tractography

    Directory of Open Access Journals (Sweden)

    Yongxin eLi


    Full Text Available Evidence supports the notion that the fusiform gyrus (FG, as an integral part of the ventral occipitotemporal junction, is involved widely in cognitive processes as perceiving faces, objects, places or words, and this region also might represent the visual form of an abacus in the abacus-based mental calculation process. The current study uses a combined voxel-based morphometry (VBM and diffusion tensor imaging (DTI analysis to test whether long-term abacus training could induce structural changes in the left FG and in the white matter (WM tracts distribution connecting with this region in school children. We found that, abacus-trained children exhibited significant smaller grey matter (GM volume than controls in the left FG. And the connectivity mapping identified left forceps major as a key pathway connecting left FG with other brain areas in the trained group, but not in the controls. Furthermore, mean fractional anisotropy (FA values within left forceps major were significantly increased in the trained group. Interestingly, a significant negative correlation was found in the trained group between the GM volume in left FG and the mean FA value in left forceps major, suggesting an inverse effect of the reported GM and WM structural changes. In the control group, a positive correlation between left FG GM volume and tract FA was found as well. This analysis visualized the group level differences in GM volume, FA and fiber tract between the abacus-trained children and the controls, and provided the first evidence that GM volume change in the left FG is intimately linked with the micro-structural properties of the left forceps major tracts. The present results demonstrate the structural changes in the left FG from the intracortical GM to the subcortical WM regions and provide insights into the neural mechanism of structural plasticity induced by abacus training.

  11. Structural changes in left fusiform areas and associated fiber connections in children with abacus training: evidence from morphometry and tractography. (United States)

    Li, Yongxin; Wang, Yunqi; Hu, Yuzheng; Liang, Yurong; Chen, Feiyan


    Evidence supports the notion that the fusiform gyrus (FG), as an integral part of the ventral occipitotemporal junction, is involved widely in cognitive processes as perceiving faces, objects, places or words, and this region also might represent the visual form of an abacus in the abacus-based mental calculation process. The current study uses a combined voxel-based morphometry (VBM) and diffusion tensor imaging (DTI) analysis to test whether long-term abacus training could induce structural changes in the left FG and in the white matter (WM) tracts distribution connecting with this region in school children. We found that, abacus-trained children exhibited significant smaller gray matter (GM) volume than controls in the left FG. And the connectivity mapping identified left forceps major as a key pathway connecting left FG with other brain areas in the trained group, but not in the controls. Furthermore, mean fractional anisotropy (FA) values within left forceps major were significantly increased in the trained group. Interestingly, a significant negative correlation was found in the trained group between the GM volume in left FG and the mean FA value in left forceps major, suggesting an inverse effect of the reported GM and WM structural changes. In the control group, a positive correlation between left FG GM volume and tract FA was found as well. This analysis visualized the group level differences in GM volume, FA and fiber tract between the abacus-trained children and the controls, and provided the first evidence that GM volume change in the left FG is intimately linked with the micro-structural properties of the left forceps major tracts. The present results demonstrate the structural changes in the left FG from the intracortical GM to the subcortical WM regions and provide insights into the neural mechanism of structural plasticity induced by abacus training.

  12. Anatomic relationship between left coronary artery and left atrium in patients undergoing atrial fibrillation ablation. (United States)

    Anselmino, Matteo; Torri, Federica; Ferraris, Federico; Calò, Leonardo; Castagno, Davide; Gili, Sebastiano; Rovera, Chiara; Giustetto, Carla; Gaita, Fiorenzo


    Atrial fibrillation transcatheter ablation (TCA) is, within available atrial fibrillation rhythm control strategies, one of the most effective. To potentially improve ablation outcome in case of recurrent atrial fibrillation after a first procedure or in presence of structural myocardial disease, isolation of the pulmonary veins may be associated with extensive lesions within the left atrium. To avoid rare, but potentially life-threatening, complications, thorough knowledge and assessment of left atrium anatomy and its relation to structures in close proximity are, therefore, mandatory. Aim of the present study is to describe, by cardiac computed tomography, the anatomic relationship between aortic root, left coronary artery and left atrium in patients undergoing atrial fibrillation TCA. The cardiac computed tomography scan of 21 patients affected by atrial fibrillation was elaborated to segment left atrium, aortic root and left coronary artery from the surrounding structures and the following distances measured: left atrium and aortic root; left atrium roof and aortic root; left main coronary artery and left atrium; circumflex artery and left atrium appendage; and circumflex artery and mitral valve annulus. Above all, the median distance between left atrium and aortic root (1.9, 1.5-2.1 mm), and between circumflex artery and left atrium appendage ostium (3.0, 2.1-3.4 mm) were minimal (≤3 mm). None of measured distances significantly varied between patients presenting paroxysmal versus persistent atrial fibrillation. The anatomic relationship between left atrium and coronary arteries is extremely relevant when performing atrial fibrillation TCA by extensive lesions. Therefore, at least in the latter case, preablation imaging should be recommended to avoid rare, but potentially life-threatening, complications with the aim of an as well tolerated as possible procedure.

  13. Is there a role of visual cortex in spatial hearing? (United States)

    Zimmer, Ulrike; Lewald, Jörg; Erb, Michael; Grodd, Wolfgang; Karnath, Hans-Otto


    The integration of auditory and visual spatial information is an important prerequisite for accurate orientation in the environment. However, while visual spatial information is based on retinal coordinates, the auditory system receives information on sound location in relation to the head. Thus, any deviation of the eyes from a central position results in a divergence between the retinal visual and the head-centred auditory coordinates. It has been suggested that this divergence is compensated for by a neural coordinate transformation, using a signal of eye-in-head position. Using functional magnetic resonance imaging, we investigated which cortical areas of the human brain participate in such auditory-visual coordinate transformations. Sounds were produced with different interaural level differences, leading to left, right or central intracranial percepts, while subjects directed their gaze to visual targets presented to the left, to the right or straight ahead. When gaze was to the left or right, we found the primary visual cortex (V1/V2) activated in both hemispheres. The occipital activation did not occur with sound lateralization per se, but was found exclusively in combination with eccentric eye positions. This result suggests a relation of neural processing in the visual cortex and the transformation of auditory spatial coordinates responsible for maintaining the perceptual alignment of audition and vision with changes in gaze direction.

  14. Multisensory stimuli improve relative localisation judgments compared to unisensory auditory or visual stimuli


    Bizley, Jennifer; Wood, Katherine; Freeman, Laura


    Observers performed a relative localisation task in which they reported whether the second of two sequentially presented signals occurred to the left or right of the first. Stimuli were detectability-matched auditory, visual, or auditory-visual signals and the goal was to compare changes in performance with eccentricity across modalities. Visual performance was superior to auditory at the midline, but inferior in the periphery, while auditory-visual performance exceeded both at all locations....

  15. Visuokinesthetic Perception of Hand Movement is Mediated by Cerebro–Cerebellar Interaction between the Left Cerebellum and Right Parietal Cortex (United States)

    Hagura, Nobuhiro; Oouchida, Yutaka; Aramaki, Yu; Okada, Tomohisa; Matsumura, Michikazu; Sadato, Norihiro


    Combination of visual and kinesthetic information is essential to perceive bodily movements. We conducted behavioral and functional magnetic resonance imaging experiments to investigate the neuronal correlates of visuokinesthetic combination in perception of hand movement. Participants experienced illusory flexion movement of their hand elicited by tendon vibration while they viewed video-recorded flexion (congruent: CONG) or extension (incongruent: INCONG) motions of their hand. The amount of illusory experience was graded by the visual velocities only when visual information regarding hand motion was concordant with kinesthetic information (CONG). The left posterolateral cerebellum was specifically recruited under the CONG, and this left cerebellar activation was consistent for both left and right hands. The left cerebellar activity reflected the participants' intensity of illusory hand movement under the CONG, and we further showed that coupling of activity between the left cerebellum and the “right” parietal cortex emerges during this visuokinesthetic combination/perception. The “left” cerebellum, working with the anatomically connected high-order bodily region of the “right” parietal cortex, participates in online combination of exteroceptive (vision) and interoceptive (kinesthesia) information to perceive hand movement. The cerebro–cerebellar interaction may underlie updating of one's “body image,” when perceiving bodily movement from visual and kinesthetic information. PMID:18453537

  16. Beware the left-sided gallbladder

    African Journals Online (AJOL)

    %, and is defined as a gallbladder located to the left of the ligamentum teres and the falciform ligament.1 LSGB was first described by Hochstetter in 1886, and its identification is important because of the numerous and potentially hazardous.

  17. Introduction to left-right symmetric models

    International Nuclear Information System (INIS)

    Grimus, W.


    We motivate left-right symmetric models by the possibility of spontaneous parity breaking. Then we describe the multiplets and the Lagrangian of such models. Finally we discuss lower bounds on the right-handed scale. (author)

  18. Electrocardiographic features suggestive of a left. ventricular ...

    African Journals Online (AJOL)

    Abstract. Electrocardiographic features suggestive of a transmural anterior myocardial infarction with resultant left ventricular aneurysm formation were found in a 22-year-old man who had sustained a ballistic missile injury to his chest.

  19. The role of human ventral visual cortex in motion perception (United States)

    Saygin, Ayse P.; Lorenzi, Lauren J.; Egan, Ryan; Rees, Geraint; Behrmann, Marlene


    Visual motion perception is fundamental to many aspects of visual perception. Visual motion perception has long been associated with the dorsal (parietal) pathway and the involvement of the ventral ‘form’ (temporal) visual pathway has not been considered critical for normal motion perception. Here, we evaluated this view by examining whether circumscribed damage to ventral visual cortex impaired motion perception. The perception of motion in basic, non-form tasks (motion coherence and motion detection) and complex structure-from-motion, for a wide range of motion speeds, all centrally displayed, was assessed in five patients with a circumscribed lesion to either the right or left ventral visual pathway. Patients with a right, but not with a left, ventral visual lesion displayed widespread impairments in central motion perception even for non-form motion, for both slow and for fast speeds, and this held true independent of the integrity of areas MT/V5, V3A or parietal regions. In contrast with the traditional view in which only the dorsal visual stream is critical for motion perception, these novel findings implicate a more distributed circuit in which the integrity of the right ventral visual pathway is also necessary even for the perception of non-form motion. PMID:23983030

  20. No Child Left Inside Week: Pilot Program


    Clark, Jamie C.


    This program evaluation assessed the feasibility and effectiveness of a free No Child Left Inside (NCLI) week-long outdoor program to coincide with the Utah state-designated No Child Left Inside Week. The pilot program was implemented at the community level in Cache Valley, Utah, in 2012. Families attended eleven activities throughout the week that included hands-on experience and participation. A community BioBlitz was also planned as a conclusion to the week. Survey results demonstrate incr...

  1. Severe personality changes after unilateral left paramedian thalamic infarct. (United States)

    Fukutake, Toshio; Akada, Koichi; Ito, Shoichi; Okuda, Tomoko; Ueki, Yoshihiro


    Personality changes are not uncommon after paramedian thalamic infarction, but usually bilateral or relatively large lesions, often complicated by other neurological or neuropsychological deficits, are present. 'Pure' cases of unilateral lesions are extremely rare. We report that a right-handed, 48-year-old man, who was hypertensive and diabetic but had no prior psychiatric history, developed severe personality changes and a frontal-like syndrome after recovery from acute-onset impairment of consciousness at the age of 43. Other neurological and neuropsychological disturbances, especially verbal and visual amnesia, were unremarkable. MRI showed a very small infarct in the left paramedian area of the thalamus, mainly involving the dorsomedial nucleus. Copyright 2002 S. Karger AG, Basel

  2. A neural network model of lateralization during letter identification. (United States)

    Shevtsova, N; Reggia, J A


    The causes of cerebral lateralization of cognitive and other functions are currently not well understood. To investigate one aspect of function lateralization, a bihemispheric neural network model for a simple visual identification task was developed that has two parallel interacting paths of information processing. The model is based on commonly accepted concepts concerning neural connectivity, activity dynamics, and synaptic plasticity. A combination of both unsupervised (Hebbian) and supervised (Widrow-Hoff) learning rules is used to train the model to identify a small set of letters presented as input stimuli in the left visual hemifield, in the central position, and in the right visual hemifield. Each visual hemifield projects onto the contralateral hemisphere, and the two hemispheres interact via a simulated corpus callosum. The contribution of each individual hemisphere to the process of input stimuli identification was studied for a variety of underlying asymmetries. The results indicate that multiple asymmetries may cause lateralization. Lateralization occurred toward the side having larger size, higher excitability, or higher learning rate parameters. It appeared more intensively with strong inhibitory callosal connections, supporting the hypothesis that the corpus callosum plays a functionally inhibitory role. The model demonstrates clearly the dependence of lateralization on different hemisphere parameters and suggests that computational models can be useful in better understanding the mechanisms underlying emergence of lateralization.

  3. Drilling simulated temporal bones with left-handed tools: a left-hander's right? (United States)

    Torgerson, Cory S; Brydges, Ryan; Chen, Joseph M; Dubrowski, Adam


    Left-handed trainees can be at a disadvantage in the surgical environment because of a right-handed bias. The effectiveness of teaching left-handed trainees to use an otologic drill designed for their dominant hand versus the conventional right-handed drill was examined. Novice medical students were recruited from the university community. Twenty-four subjects were left-handed, and 12 were right-handed. Eight left-handed surgeons also participated. A randomized controlled trial was conducted to compare the performance of left-handed trainees using novel left-handed drills to that of left-handed trainees using right-handed tools and to that of right-handed trainees using right-handed tools. The evaluation consisted of 3 phases: pretest, skill acquisition, and 2 post-tests. The measurement tools included expert assessment of performance, and subjective and objective final product analyses. An initial construct validity phase was conducted in which validity of the assessment tools was ensured. Both the left-handers using left-handed tools and the right-handers using right-handed tools significantly outperformed the left-handers using right-handed tools at pretest, immediate posttest, and delayed posttest. All participants improved their performance as a function of practice. The left-handed trainees learned bone drilling better with tools designed for the left hand. These tools may be incorporated into residency training programs for the development of surgical technical skills. Future studies should assess skill transfer between the left-handed and right-handed drills.

  4. When left is not right: handedness effects on learning object-manipulation words using pictures with left- or right-handed first-person perspectives. (United States)

    de Nooijer, Jacqueline A; van Gog, Tamara; Paas, Fred; Zwaan, Rolf A


    According to the body-specificity hypothesis, hearing action words creates body-specific mental simulations of the actions. Handedness should, therefore, affect mental simulations. Given that pictures of actions also evoke mental simulations and often accompany words to be learned, would pictures that mismatch the mental simulation of words negatively affect learning? We investigated effects of pictures with a left-handed, right-handed, or bimanual perspective on left- and right-handers' learning of object-manipulation words in an artificial language. Right-handers recalled fewer definitions of words learned with a corresponding left-handed-perspective picture than with a right-handed-perspective picture. For left-handers, there was no effect of perspective. These findings suggest that mismatches between pictures and mental simulations evoked by hearing action words can negatively affect right-handers' learning. Left-handers, who encounter the right-handed perspective frequently, could presumably overcome the lack of motor experience with visual experience and, therefore, not be influenced by picture perspective.

  5. Left sided circumaortic and retroaortic left renal veins, renal artery arising from iliac common artery in L-shaped kidney

    International Nuclear Information System (INIS)

    Al-Amin, M.


    Full text: Introduction: Renal ectopia is a congenital anomaly with variable clinical presentation. Kidneys are normally located in the retroperitoneal position, on either side of vertebral column, against the psoas muscles but when not at such position, it is called renal ectopia or ectopic kidney. Ectopic kidneys are thought to occur in approximately 1 in 1,000 births but only about 1 in 10 of these is ever diagnosed. In 90% of crossed ectopy, there is at least partial fusion of the kidneys. Left-to right ectopy is thought to be three times more common. Some of these are discovered incidentally, when a child or adult is having ultrasonography for a medical condition unrelated to renal ectopia. In a crossed fused renal ectopic kidney, complications such as nephrolithiasis, infection, and hydronephrosis approaches over 50%. Simple renal ectopia refers to kidney that is located on the proper side but abnormal in position. Crossed renal ectopia was first described by Pannorlus in 1964 and refer to kidney that has crossed from left to right or vice-versa, with moving of one kidney to the opposite side following ascent of the other kidney, so that both kidneys are located on the same side of the body, mostly fused called crossed fused ectopia. The fusion of the two kidneys is believed to result from (1) failure of the primitive nephrogenic cell masses to separate or (2) fusion of the two blastemas during their abdominal ascent. Discussion: A 57-year-old woman with a new found hematological disease. CT exam was performed with intravenous application of contrast media. Like an additional findings we visualized the presence of right to-left ectopy (L - shaped kidney) and the presence of left circumaortic renal vein emanating from a normally situated left kidney and retroaortic renal vein as having been located by the ectopic right kidney. Conclusion: By crossed renal ectopia is meant congenital displacement of one kidney to the opposite side. The conditional may present

  6. Garner-Interference in left-handed awkward grasping. (United States)

    Eloka, Owino; Feuerhake, Felix; Janczyk, Markus; Franz, Volker H


    The Perception-Action Model (PAM) claims to provide a coherent interpretation of data from all areas of the visual neurosciences, most notably data from neuropsychological patients and from behavioral experiments in healthy people. Here, we tested two claims that are part of the core version of the PAM: (a) certain actions (natural, highly practiced, and right-handed) are controlled by the dorsal vision for action pathway, while other actions (awkward, unpracticed, or left-handed) are controlled by the ventral vision for perception pathway. (b) Only the dorsal pathway operates in an analytical fashion, being able to selectively focus on the task-relevant dimension of an object (Ganel and Goodale, Nature 426(6967):664-667, 2003). We show that one of these claims must be wrong: using the same test for analytical processing as Ganel and Goodale (2003), we found that even an action that should clearly be ventral (left-handed awkward grasping) shows analytical processing just as a dorsal task does (right-handed natural precision grasping). These results are at odds with the PAM and point to an inconsistency of the model.

  7. Comparison of exercise radionuclide angiography with thallium SPECT imaging for detection of significant narrowing of the left circumflex coronary artery

    International Nuclear Information System (INIS)

    Dilsizian, V.; Perrone-Filardi, P.; Cannon, R.O. III; Freedman, N.M.; Bacharach, S.L.; Bonow, R.O.


    Although quantitation of exercise thallium tomograms has enhanced the noninvasive diagnosis and localization of coronary artery disease, the detection of stenosis of the left circumflex coronary artery remains suboptimal. Because posterolateral regional wall motion during exercise is well assessed by radionuclide angiography, this study determined whether regional dysfunction of the posterolateral wall during exercise radionuclide angiography is more sensitive in identifying left circumflex disease than thallium perfusion abnormalities assessed by single-photon emission computed tomography (SPECT). One hundred ten consecutive patients with CAD were studied, of whom 70 had a significant stenosis of the left circumflex coronary artery or a major obtuse marginal branch. Both regional function and segmental thallium activity of the posterolateral wall were assessed using visual and quantitative analysis. Left ventricular regional function was assessed objectively by dividing the left ventricular region of interest into 20 sectors; the 8 sectors corresponding to the posterolateral free wall were used to assess function in the left circumflex artery distribution. Similarly, using circumferential profile analysis of short-axis thallium tomograms, left ventricular myocardial activity was subdivided into 64 sectors; the 16 sectors corresponding to the posterolateral region were used to assess thallium perfusion abnormalities in the left circumflex artery territory. Qualitative posterolateral wall motion analysis detected 76% of patients with left circumflex coronary artery stenosis, with a specificity of 83%, compared with only 44% by qualitative thallium tomography (p less than 0.001) and a specificity of 92%

  8. Cortical visual impairment


    Koželj, Urša


    In this thesis we discuss cortical visual impairment, diagnosis that is in the developed world in first place, since 20 percent of children with blindness or low vision are diagnosed with it. The objectives of the thesis are to define cortical visual impairment and the definition of characters suggestive of the cortical visual impairment as well as to search for causes that affect the growing diagnosis of cortical visual impairment. There are a lot of signs of cortical visual impairment. ...

  9. Visual Processing Speed


    Owsley, Cynthia


    Older adults commonly report difficulties in visual tasks of everyday living that involve visual clutter, secondary task demands, and time sensitive responses. These difficulties often cannot be attributed to visual sensory impairment. Techniques for measuring visual processing speed under divided attention conditions and among visual distractors have been developed and have established construct validity in that those older adults performing poorly in these tests are more likely to exhibit d...

  10. Sex differences and functional hemispheric asymmetries during number comparison. (United States)

    Harris, TiAnni; Scheuringer, Andrea; Pletzer, Belinda


    Global-local stimuli are hierarchical structures consisting of a larger global structure which is composed of smaller local stimuli. Numbers are also constructed hierarchically, with multi-digit numbers being made up from single digits. During two-digit number comparison, compatible items (larger number contains larger unit digit, e.g., 53 vs. 68) are processed faster and more accurately than incompatible items (smaller number contains larger unit digit, e.g., 58 vs. 63). This so-called unit-decade-compatibility effect has challenged the holistic model of number processing and suggests that the processing of number magnitudes occurs at least in part, decomposed, i.e., separately for each digit. Thus, the compatibility effect is indicative of how decomposed numbers are processed, thereby sharing similarities with traditional global-local processing of hierarchical stimuli. The goal of this study was to investigate whether factors that have been shown to reliably influence global-local processing also affect the compatibility effect during number comparison. Those include visual hemifield, sex, and menstrual cycle phase in women. One hundred sixty participants, 77 naturally cycling women and 83 men, completed a two-digit number comparison task twice, with test-sessions time-locked to the early follicular or mid-luteal cycle phase in women. Number comparison stimuli were presented to the right or left hemifield, respectively. We observed a stronger compatibility effect in the right visual hemifield compared to left visual hemifield and in women compared to men, but no evidence for an influence of menstrual cycle phase in women could be found. Hemispheric asymmetries in holistic versus decomposed number processing could be demonstrated for the first time, suggesting a similar hemispheric modulation for number magnitude processing as for global-local processing.

  11. Visual Attention in Posterior Stroke and Relations to Alexia

    DEFF Research Database (Denmark)

    Petersen, Anders; Vangkilde, Signe; Fabricius, Charlotte


    that reduced visual speed and span may explain pure alexia. Eight patients with unilateral PCA strokes (four left hemisphere, four right hemisphere) were selected on the basis of lesion location, rather than the presence of any visual symptoms. Visual attention was characterized by a whole report paradigm......Impaired visual attention is common following strokes in the territory of the middle cerebral artery, particularly in the right hemisphere, while attentional effects of more posterior lesions are less clear. Commonly, such deficits are investigated in relation to specific syndromes like visual...... agnosia or pure alexia. The aim of this study was to characterize visual processing speed and apprehension span following posterior cerebral artery (PCA) stroke. In addition, the relationship between these attentional parameters and single word reading is investigated, as previous studies have suggested...

  12. Visual Disability Among Juvenile Open-angle Glaucoma Patients. (United States)

    Gupta, Viney; Ganesan, Vaitheeswaran L; Kumar, Sandip; Chaurasia, Abadh K; Malhotra, Sumit; Gupta, Shikha


    Juvenile onset primary open-angle glaucoma (JOAG) unlike adult onset primary open-angle glaucoma presents with high intraocular pressure and diffuse visual field loss, which if left untreated leads to severe visual disability. The study aimed to evaluate the extent of visual disability among JOAG patients presenting to a tertiary eye care facility. Visual acuity and perimetry records of unrelated JOAG patients presenting to our Glaucoma facility were analyzed. Low vision and blindness was categorized by the WHO criteria and percentage impairment was calculated as per the guidelines provided by the American Medical Association (AMA). Fifty-two (15%) of the 348 JOAG patients were bilaterally blind at presentation and 32 (9%) had low vision according to WHO criteria. Ninety JOAG patients (26%) had a visual impairment of 75% or more. Visual disability at presentation among JOAG patients is high. This entails a huge economic burden, given their young age and associated social responsibilities.

  13. Extradural Optic Nerve Decompression for Fibrous Dysplasia with a Favorable Visual Outcome : Case Report


    Kurimoto, Masanori; Endo, Shunro; Onizuka, Keiichiro; Akai, Takuya; Takaku, Akira


    A 10-year-old boy with progressive left visual disturbance associated with craniobasal fibrous dysplasia underwent left frontotemporal craniotomy. Dysplastic lesions of the sphenoid ridge, orbital roof, anterior clinoid, and ethmoid sinus were removed through an extradural pterional approach and the optic nerve was completely decompressed. His vision was markedly improved postoperatively. Consecutive follow-up studies for 3 years have shown no deterioration of his visual acuity. Early optic n...

  14. Left Right Patterning, Evolution and Cardiac Development

    Directory of Open Access Journals (Sweden)

    Iain M. Dykes


    Full Text Available Many aspects of heart development are determined by the left right axis and as a result several congenital diseases have their origins in aberrant left-right patterning. Establishment of this axis occurs early in embryogenesis before formation of the linear heart tube yet impacts upon much later morphogenetic events. In this review I discuss the differing mechanisms by which left-right polarity is achieved in the mouse and chick embryos and comment on the evolution of this system. I then discus three major classes of cardiovascular defect associated with aberrant left-right patterning seen in mouse mutants and human disease. I describe phenotypes associated with the determination of atrial identity and venous connections, looping morphogenesis of the heart tube and finally the asymmetric remodelling of the embryonic branchial arch arterial system to form the leftward looped arch of aorta and associated great arteries. Where appropriate, I consider left right patterning defects from an evolutionary perspective, demonstrating how developmental processes have been modified in species over time and illustrating how comparative embryology can aide in our understanding of congenital heart disease.

  15. Left behind radiological investigations: An inherent problem

    Directory of Open Access Journals (Sweden)

    Giridhar A Govindswamy


    Full Text Available Objectives: To assess the number of investigations left behind by patients in radiology department, their cost, and the possible methods of reducing the problem. Materials and Methods: A total of 1424 radiographs, 160 computed tomography (CT scans, 300 ultrasonography (USG reports, and 46 Doppler reports were left behind by patients in one financial year. The total cost of these left behind investigations was calculated and the reports were categorized into normal and abnormal for each modality. Results: Of the radiographs left behind 658 were abnormal, with 211 among these being radiographs of postoperative patients. Thirty-seven percent of CT scans had positive findings. Sixty-eight percent of USG reports had positive findings while 46% of Doppler reports were abnormal. Conclusion: We believe that the cost and number of these left behind investigations over a period of time would definitely be significant for the health care system in a developing country. It is time to think of the possible reasons and methods for containing this problem.

  16. Early clinical and subclinical visual evoked potential and Humphrey's visual field defects in cryptococcal meningitis.

    Directory of Open Access Journals (Sweden)

    Anand Moodley

    Full Text Available Cryptococcal induced visual loss is a devastating complication in survivors of cryptococcal meningitis (CM. Early detection is paramount in prevention and treatment. Subclinical optic nerve dysfunction in CM has not hitherto been investigated by electrophysiological means. We undertook a prospective study on 90 HIV sero-positive patients with culture confirmed CM. Seventy-four patients underwent visual evoked potential (VEP testing and 47 patients underwent Humphrey's visual field (HVF testing. Decreased best corrected visual acuity (BCVA was detected in 46.5% of patients. VEP was abnormal in 51/74 (68.9% right eyes and 50/74 (67.6% left eyes. VEP P100 latency was the main abnormality with mean latency values of 118.9 (±16.5 ms and 119.8 (±15.7 ms for the right and left eyes respectively, mildly prolonged when compared to our laboratory references of 104 (±10 ms (p<0.001. Subclinical VEP abnormality was detected in 56.5% of normal eyes and constituted mostly latency abnormality. VEP amplitude was also significantly reduced in this cohort but minimally so in the visually unimpaired. HVF was abnormal in 36/47 (76.6% right eyes and 32/45 (71.1% left eyes. The predominant field defect was peripheral constriction with an enlarged blind spot suggesting the greater impact by raised intracranial pressure over that of optic neuritis. Whether this was due to papilloedema or a compartment syndrome is open to further investigation. Subclinical HVF abnormalities were minimal and therefore a poor screening test for early optic nerve dysfunction. However, early optic nerve dysfunction can be detected by testing of VEP P100 latency, which may precede the onset of visual loss in CM.

  17. Visualization analysis and design

    CERN Document Server

    Munzner, Tamara


    Visualization Analysis and Design provides a systematic, comprehensive framework for thinking about visualization in terms of principles and design choices. The book features a unified approach encompassing information visualization techniques for abstract data, scientific visualization techniques for spatial data, and visual analytics techniques for interweaving data transformation and analysis with interactive visual exploration. It emphasizes the careful validation of effectiveness and the consideration of function before form. The book breaks down visualization design according to three questions: what data users need to see, why users need to carry out their tasks, and how the visual representations proposed can be constructed and manipulated. It walks readers through the use of space and color to visually encode data in a view, the trade-offs between changing a single view and using multiple linked views, and the ways to reduce the amount of data shown in each view. The book concludes with six case stu...

  18. Four Functionally Distinct Regions in the Left Supramarginal Gyrus Support Word Processing


    Oberhuber, M.; Hope, T. M. H.; Seghier, M. L.; Parker Jones, O.; Prejawa, S.; Green, D. W.; Price, C. J


    We used fMRI in 85 healthy participants to investigate whether different parts of the left supramarginal gyrus (SMG) are involved in processing phonological inputs and outputs. The experiment involved 2 tasks (speech production (SP) and one-back (OB) matching) on 8 different types of stimuli that systematically varied the demands on sensory processing (visual vs. auditory), sublexical phonological input (words and pseudowords vs. nonverbal stimuli), and semantic content (words and objects vs....

  19. Demonstration of ascending aorta in hypoplastic left heart syndrome with aortic atresia by balloon occlusion aortography

    International Nuclear Information System (INIS)

    Lo, R.N.S.; Leung, M.P.; Lau, K.C.


    Balloon occlusion angiography in the descending aorta produced clear retrograde visualization of the hypoplastic ascending aorta and related structures in eighteen neonates with aortic atresia. Transient bradycardia was the only complication observed. It is technically simpler than retrograde cannulation of the aorta via an arteriotomy and should be the method of choice when cardiac catheterization is required in patients with the hypoplastic left heart syndrome. (orig.)

  20. Optimization of factor analysis of the left ventricle in echocardiography for detecting wall motion abnormalities. (United States)

    Diebold, Benoît; Delouche, Annie; Abergel, Eric; Raffoul, Hanna; Diebold, Hervé; Frouin, Frédérique


    This study has tested solutions to optimize the ability of factor analysis of the left ventricle in echocardiography (FALVE) to detect segmental wall motion abnormalities automatically. On four- and two-chamber views of 38 patients, two factors (one flat curve and one curve describing the contraction-relaxation sequence) were extracted and associated factor images were combined to synthesize a parametric image (constant image in green, positive/negative values of the contraction-relaxation image in red/blue). The segments were graded on the visual and the parametric views. The impact of selecting a whole cardiac cycle, masking the left ventricle and realigning the image sequence on the results, was demonstrated. Systematic realignment had a positive impact, especially for patients with left bundle branch block or pacemaker. After alignment, for the entire population, the absolute concordance was 68.6% and the relative concordance (within one grade) was 99%. Thus, FALVE is promising for detecting segmental wall motion abnormalities.

  1. Visual search in unilateral spatial neglect: The effects of distractors on a dynamic visual search task. (United States)

    Emerson, Rebeca Lauren; García-Molina, Alberto; López Carballo, Jaume; García Fernández, Juan; Aparicio-López, Celeste; Novo, Junquera; Sánchez-Carrión, Rocío; Enseñat-Cantallops, Antonia; Peña-Casanova, Jordi


    The objective of this study was to examine visual scanning performance in patients with Unilateral Spatial Neglect (USN) in a visual search task. Thirty-one right hemisphere stroke patients with USN were recruited. They performed a dynamic visual search task with two conditions, with and without distractors, while eye movements were monitored with an eye-tracker. The main goal of the task was to select target stimuli that appeared from the top of the screen and moved vertically downward. Target detection and visual scanning percentage were assessed over two hemispaces (right, left) on two conditions (distractor, no distractor). Most Scanned Regions (MSR) were calculated to analyze the areas of the screen where most points of fixation were directed to. Higher target detection rate and visual scanning percentages were found on the right hemispace on both conditions. From the MSRs we found that participants with a center of attention further to the right of the screen also presented smaller overall MSRs. Right hemisphere stroke patients with USN presented not only a significant rightward bias but reduced overall search areas, implying hyperattention does not only restrict search on the horizontal (right-left) axis but the vertical axis (top-bottom) too.

  2. The Visual What For Area

    DEFF Research Database (Denmark)

    Starrfelt, Randi; Gerlach, Christian


    An area in the left fusiform gyrus labelled the Visual Word Form Area (VWFA) is claimed to be especially, or even selectively, responsive to words. We explored how stimulus type and task demands affect activity in this area by conducting a PET experiment where words and pictures were presented...... in two conditions that differed in demands on shape processing: colour decision and categorization. The subjects also performed an object decision task with pictures only. The imaging data revealed a main effect of stimulus type: rCBF was higher during word compared with picture processing. When compared...... individually for colour decision and categorization, the difference between words and pictures was only significant during colour decision, although a trend was present during categorization also. rCBF in the VWFA was highest during the object decision task, where only pictures were presented. Our findings...

  3. Temporal dynamics of visual working memory. (United States)

    Sobczak-Edmans, M; Ng, T H B; Chan, Y C; Chew, E; Chuang, K H; Chen, S H A


    The involvement of the human cerebellum in working memory has been well established in the last decade. However, the cerebro-cerebellar network for visual working memory is not as well defined. Our previous fMRI study showed superior and inferior cerebellar activations during a block design visual working memory task, but specific cerebellar contributions to cognitive processes in encoding, maintenance and retrieval have not yet been established. The current study examined cerebellar contributions to each of the components of visual working memory and presence of cerebellar hemispheric laterality was investigated. 40 young adults performed a Sternberg visual working memory task during fMRI scanning using a parametric paradigm. The contrast between high and low memory load during each phase was examined. We found that the most prominent activation was observed in vermal lobule VIIIb and bilateral lobule VI during encoding. Using a quantitative laterality index, we found that left-lateralized activation of lobule VIIIa was present in the encoding phase. In the maintenance phase, there was bilateral lobule VI and right-lateralized lobule VIIb activity. Changes in activation in right lobule VIIIa were present during the retrieval phase. The current results provide evidence that superior and inferior cerebellum contributes to visual working memory, with a tendency for left-lateralized activations in the inferior cerebellum during encoding and right-lateralized lobule VIIb activations during maintenance. The results of the study are in agreement with Baddeley's multi-component working memory model, but also suggest that stored visual representations are additionally supported by maintenance mechanisms that may employ verbal coding. Copyright © 2015 Elsevier Inc. All rights reserved.

  4. Left-Wing Extremism: The Current Threat

    Energy Technology Data Exchange (ETDEWEB)

    Karl A. Seger


    Left-wing extremism is ''alive and well'' both in the US and internationally. Although the current domestic terrorist threat within the U. S. is focused on right-wing extremists, left-wing extremists are also active and have several objectives. Leftist extremists also pose an espionage threat to U.S. interests. While the threat to the U.S. government from leftist extremists has decreased in the past decade, it has not disappeared. There are individuals and organizations within the U.S. who maintain the same ideology that resulted in the growth of left-wing terrorism in this country in the 1970s and 1980s. Some of the leaders from that era are still communicating from Cuba with their followers in the U.S., and new leaders and groups are emerging.

  5. Enhancement of Visual Field Predictions with Pointwise Exponential Regression (PER) and Pointwise Linear Regression (PLR). (United States)

    Morales, Esteban; de Leon, John Mark S; Abdollahi, Niloufar; Yu, Fei; Nouri-Mahdavi, Kouros; Caprioli, Joseph


    The study was conducted to evaluate threshold smoothing algorithms to enhance prediction of the rates of visual field (VF) worsening in glaucoma. We studied 798 patients with primary open-angle glaucoma and 6 or more years of follow-up who underwent 8 or more VF examinations. Thresholds at each VF location for the first 4 years or first half of the follow-up time (whichever was greater) were smoothed with clusters defined by the nearest neighbor (NN), Garway-Heath, Glaucoma Hemifield Test (GHT), and weighting by the correlation of rates at all other VF locations. Thresholds were regressed with a pointwise exponential regression (PER) model and a pointwise linear regression (PLR) model. Smaller root mean square error (RMSE) values of the differences between the observed and the predicted thresholds at last two follow-ups indicated better model predictions. The mean (SD) follow-up times for the smoothing and prediction phase were 5.3 (1.5) and 10.5 (3.9) years. The mean RMSE values for the PER and PLR models were unsmoothed data, 6.09 and 6.55; NN, 3.40 and 3.42; Garway-Heath, 3.47 and 3.48; GHT, 3.57 and 3.74; and correlation of rates, 3.59 and 3.64. Smoothed VF data predicted better than unsmoothed data. Nearest neighbor provided the best predictions; PER also predicted consistently more accurately than PLR. Smoothing algorithms should be used when forecasting VF results with PER or PLR. The application of smoothing algorithms on VF data can improve forecasting in VF points to assist in treatment decisions.

  6. Interaction for visualization

    CERN Document Server

    Tominski, Christian


    Visualization has become a valuable means for data exploration and analysis. Interactive visualization combines expressive graphical representations and effective user interaction. Although interaction is an important component of visualization approaches, much of the visualization literature tends to pay more attention to the graphical representation than to interaction.The goal of this work is to strengthen the interaction side of visualization. Based on a brief review of general aspects of interaction, we develop an interaction-oriented view on visualization. This view comprises five key as

  7. Visual memory and visual perception: when memory improves visual search. (United States)

    Riou, Benoit; Lesourd, Mathieu; Brunel, Lionel; Versace, Rémy


    This study examined the relationship between memory and perception in order to identify the influence of a memory dimension in perceptual processing. Our aim was to determine whether the variation of typical size between items (i.e., the size in real life) affects visual search. In two experiments, the congruency between typical size difference and perceptual size difference was manipulated in a visual search task. We observed that congruency between the typical and perceptual size differences decreased reaction times in the visual search (Exp. 1), and noncongruency between these two differences increased reaction times in the visual search (Exp. 2). We argue that these results highlight that memory and perception share some resources and reveal the intervention of typical size difference on the computation of the perceptual size difference.

  8. Left ventricular performance during psychological stress

    International Nuclear Information System (INIS)

    Young, D.Z.; Massachusetts General Hospital, Boston; Dimsdale, J.E.; Moore, R.H.; Barlai-Kovach, M.; Newell, J.B.; McKusick, K.A.; Boucher, C.A.; Fifer, M.A.; Strauss, H.W.


    Left ventricular ejection fraction, systolic blood pressure and plasma norepinephrine were measured in six normotensive and six mildly hypertensive subjects during rest and psychological stress. Compared with rest, 8 of the 12 subjects developed significant changes in ejection fraction (increase in 6, decrease in 2); 10 of 12 subjects developed significant elevations of plasma norepinephrine; and all developed significant increases in systolic blood pressure. When the stress effects were examined for the total group, as opposed to within subjects, there were significant increases in plasma norepinephrine and systolic blood pressure but, interestingly, mean ejection fraction and stroke volume remained unchanged, implying stress led to increased left ventricular contractility. (orig.)

  9. Echocardiographic study of left atrial myxoma

    Directory of Open Access Journals (Sweden)

    Dalal J


    Full Text Available Four cases of left atrial myxoma were diagnosed pre-operatively by echocardiography. All cases showed characteristic echocardio-graphic features of variegated shadows behind the mitral valve in diastole and within the left atrium in systole. In two cases the my-xomas were surgically removed and confirmed on histology. In one case the post-operative echocardiogram showed complete dis-appearance of the abnormal shadows. Echocardiography is the most reliable method today for the diagnosis of a myxoma.

  10. “Getting the Left Right”

    DEFF Research Database (Denmark)

    Klinke, Marianne E.; Zahavi, Dan; Hjaltason, Haukur


    experience was captured in the overarching theme, “getting the left right,” which encompasses the two subthemes of (a) surreal awareness of the left and (b) emergence of a different world. Patients had unclear perceptions of their own body and surroundings, their attention was brittle, and they encountered...... bewildering reactions from other people. They simultaneously pursued the ineffable neglected space and searched for coherence. The vulnerability, loss, and conflicting perceptions that patients with neglect face should be acknowledged and alleviation sought. Facilitating methods should provide additional...

  11. Clustered survival data with left-truncation

    DEFF Research Database (Denmark)

    Eriksson, Frank; Martinussen, Torben; Scheike, Thomas H.


    Left-truncation occurs frequently in survival studies, and it is well known how to deal with this for univariate survival times. However, there are few results on how to estimate dependence parameters and regression effects in semiparametric models for clustered survival data with delayed entry....... Surprisingly, existing methods only deal with special cases. In this paper, we clarify different kinds of left-truncation and suggest estimators for semiparametric survival models under specific truncation schemes. The large-sample properties of the estimators are established. Small-sample properties...

  12. Left paraduodenal hernias; Hernias paraduodenales izquierdas

    Energy Technology Data Exchange (ETDEWEB)

    Lopez-Negrete, L.; Garcia-Lozano, J.; Sanchez, J. L.; Tejeiro, A.; Sala, J. [Hospital Valle del Nalon. Riano-Sama. Asturias (Spain)


    We report two cases of left paraduodenal internal hernias located in the fossa of Landzert that were diagnosed by CT. Internal hernias are an infrequent cause of acute abdomen, due to the intestinal sub occlusion they produce. Left paraduodenal hernias are responsible for about 50% of internal hernias. CT makes it possible to demonstrate the group of herniated loops between the stomach, fourth segment of the duodenum, descending colon, and tail of the pancreas. The identification of the loops in an atypical position together with displaced blood vessels (mesenteric vessels) and colon gives concerns on them a typical radiological semiology that makes them easily identifiable. (Author) 9 refs.

  13. Left ventricular assist device implantation via left thoracotomy: alternative to repeat sternotomy. (United States)

    Pierson, Richard N; Howser, Renee; Donaldson, Terri; Merrill, Walter H; Dignan, Rebecca J; Drinkwater, Davis C; Christian, Karla G; Butler, Javed; Chomsky, Don; Wilson, John R; Clark, Rick; Davis, Stacy F


    Repeat sternotomy for left ventricular assist device insertion may result in injury to the right heart or patent coronary grafts, complicating intraoperative and postoperative management. In 4 critically ill patients, left thoracotomy was used as an alternative to repeat sternotomy. Anastomosis of the outflow conduit to the descending thoracic aorta provided satisfactory hemodynamic support.

  14. The superior colliculus is sensitive to gestalt-like stimulus configuration in hemispherectomy patients. (United States)

    Georgy, Loraine; Celeghin, Alessia; Marzi, Carlo A; Tamietto, Marco; Ptito, Alain


    Patients with cortical blindness following a lesion to the primary visual cortex (V1) may retain nonconscious visual abilities (blindsight). One intriguing, though largely unexplored question, is whether nonconscious vision in the blind hemifield of hemianopic patients can be sensitive to higher-order perceptual organization, and which V1-independent structure underlies such effect. To answer this question, we tested two rare hemianopic patients who had undergone hemispherectomy, and in whom the only post-chiasmatic visual structure left intact in the same side of the otherwise damaged hemisphere was the superior colliculus (SC). By using a variant of the redundant target effect (RTE), we presented single dots, patterns composed by the same dots organized in quadruple gestalt-like configurations, or patterns of four dots arranged in random configurations, either singly to the intact visual hemifield or bilaterally to both hemifields. As reported in a number of prior studies on blindsight patients, we found that bilateral stimulation yielded faster reaction times (RTs) than single stimulation of the intact field for all conditions (i.e., there was an implicit RTE). In addition to this effect, both patients showed a further speeding up of RTs when the gestalt-like, but not the random shape, quadruple patterns were projected to their blind hemifield during bilateral stimulation. Because other retino-recipient subcortical and cortical structures in the damaged hemisphere are absent, the SC on the lesioned side seems solely responsible for such an effect. The present results provide initial support to the notion that nonconscious vision might be sensitive to perceptual organization and stimulus configuration through the pivotal contribution of the SC, which can enhance the processing of gestalt-like or structured stimuli over meaningless or randomly assembled ones and translate them into facilitatory motor outputs. Copyright © 2016 The Authors. Published by Elsevier

  15. Aligning State Standards and the Expanded Core Curriculum: Balancing the Impact of the No Child Left Behind Act (United States)

    Lohmeier, Keri L.


    How do professionals address accountability mandates that are derived from the No Child Left Behind Act and the overall educational needs of students who are visually impaired during the school day? Meeting state and federal mandates while maintaining the individuality of educational programs is challenging for all educators. Teachers of students…

  16. The Visual System

    Medline Plus

    Full Text Available ... programs with respect to blinding eye diseases, visual disorders, mechanisms of visual function, preservation of sight, and the special health problems ... Pressroom Contacts Dustin Hays - Chief, Science Communication Anna Harper - Media Relations ...

  17. Visualization of Social Networks

    NARCIS (Netherlands)

    Boertjes, E.M.; Kotterink, B.; Jager, E.J.


    Current visualizations of social networks are mostly some form of node-link diagram. Depending on the type of social network, this can be some treevisualization with a strict hierarchical structure or a more generic network visualization.

  18. The Visual System

    Medline Plus

    Full Text Available ... NIH), the National Eye Institute’s mission is to “conduct and support research, training, health information dissemination, and other programs with respect to blinding eye diseases, visual disorders, mechanisms of visual function, preservation of ...

  19. The Visual System

    Medline Plus

    Full Text Available ... is to “conduct and support research, training, health information dissemination, and other programs with respect to blinding eye diseases, visual disorders, mechanisms of visual function, preservation of sight, and the special health problems and ...

  20. Visual acuity test (United States)

    ... this page: // Visual acuity test To use the sharing features on this page, please enable JavaScript. The visual acuity test is used to determine the smallest ...

  1. Topological Methods for Visualization

    Energy Technology Data Exchange (ETDEWEB)

    Berres, Anne Sabine [Los Alamos National Lab. (LANL), Los Alamos, NM (United Stat


    This slide presentation describes basic topological concepts, including topological spaces, homeomorphisms, homotopy, betti numbers. Scalar field topology explores finding topological features and scalar field visualization, and vector field topology explores finding topological features and vector field visualization.

  2. The Visual System (United States)

    ... National Eye Institute’s mission is to “conduct and support research, training, health information dissemination, and other programs with respect to blinding eye diseases, visual disorders, mechanisms of visual function, preservation of sight, ...

  3. The Visual System

    Medline Plus

    Full Text Available ... National Eye Institute’s mission is to “conduct and support research, training, health information dissemination, and other programs with respect to blinding eye diseases, visual disorders, mechanisms of visual function, preservation of sight, ...

  4. Visual Control of Locomotion

    National Research Council Canada - National Science Library

    Loomis, Jack M; Beall, Andrew C


    The accomplishments were threefold. First, a software tool for rendering virtual environments was developed, a tool useful for other researchers interested in visual perception and visual control of action...

  5. Visual attention capacity

    DEFF Research Database (Denmark)

    Habekost, Thomas; Starrfelt, Randi


    Psychophysical studies have identified two distinct limitations of visual attention capacity: processing speed and apprehension span. Using a simple test, these cognitive factors can be analyzed by Bundesen's Theory of Visual Attention (TVA). The method has strong specificity and sensitivity...

  6. The Visual System

    Medline Plus

    Full Text Available ... to blinding eye diseases, visual disorders, mechanisms of visual function, preservation of sight, and the special health problems and requirements of ... Pressroom Contacts Dustin Hays - Chief, Science Communication Anna Harper - Media Relations ...

  7. The Visual System

    Medline Plus

    Full Text Available ... and other programs with respect to blinding eye diseases, visual disorders, mechanisms of visual function, preservation of ... National Eye Health Education Program (NEHEP) Diabetic Eye Disease Education Program Glaucoma Education Program Low Vision Education ...

  8. Magnetization of left-handed metamaterials

    International Nuclear Information System (INIS)

    Kourakis, I; Shukla, P K


    We propose a possible mechanism for the generation of magnetic fields in negative refraction index composite metamaterials. Considering the propagation of a high-frequency modulated amplitude electric field in a left-handed material (LHM), we show that the ponderomotive interaction between the field and low-frequency potential distributions leads to spontaneous generation of magnetic fields, whose form and properties are discussed

  9. Left ventricular mass: Myxoma or thrombus?

    Directory of Open Access Journals (Sweden)

    Monish S Raut


    Full Text Available Patient with embolic episode should always be evaluated for cardiac mass. Mass in left ventricular can be a myxoma or thrombus even in a normal functioning heart . In either case, mobile mass with embolic potential should be surgically resected.

  10. Left atrial myxoma with biventricular dysfunction

    Directory of Open Access Journals (Sweden)

    Monish S. Raut


    Full Text Available Occurrence of left atrial myxoma with severe ventricular dysfunction without any obstructive coronary artery disease, as presented in our case, is very rare. It may be due to undiagnosed concomitant dilated cardiomyopathy or unknown cardiodepressant effect of myxoma which warrants further research.

  11. Left atrial myxoma with biventricular dysfunction. (United States)

    Raut, Monish S; Shad, Sujay; Maheshwari, Arun


    Occurrence of left atrial myxoma with severe ventricular dysfunction without any obstructive coronary artery disease, as presented in our case, is very rare. It may be due to undiagnosed concomitant dilated cardiomyopathy or unknown cardiodepressant effect of myxoma which warrants further research. Copyright © 2016 Cardiological Society of India. Published by Elsevier B.V. All rights reserved.

  12. Vergisson 4: a left-handed Neandertal. (United States)

    Condemi, Silvana; Monge, Janet; Quertelet, Sylvain; Frayer, David W; Combier, Jean


    Handedness is an important marker for lateralization of humans in the modern and fossil record. For the most part, Neandertals and their ancestors are strongly right-handed. We describe a single tooth from a Neandertal level at Vergisson 4 (Vg 4-83). This left upper central incisor shows all the features typical of Neandertal incisors. It also exhibits a predominance of left-handed striations. Striations on the incisor's labial surface were mapped at 20x magnification using Photoshop. Angulations of the striations were determined from their deviation from the maximum mesio-distal line and were analyzed using NIH's freeware, Image J. Of the 60 labial surface striations, Vg 4-83 shows a strong predominance of left-handed striations (46; 76.7%), which are statistically significantly different (p handed striations. The identification of another left-handed Neandertal adds to our understanding about handedness variation in this fossil hominin. Given the high frequency of right-handed Neandertals, the 90: 10 modern ratio is still preserved in this group. © 2016 Wiley Periodicals, Inc.

  13. Electrocardiographic features suggestive of a left. ventricular ...

    African Journals Online (AJOL)


    Jan 1, 1983 ... sniper with an Armourlite assault rifle in Ireland. He had received a single bullet injury to the left ... His history negated any cardiovascular impairment, angina or limitation in effort tolerance. He plays ... In view of the patient's age, history and the cardiovascular findings, we would like to postulate that the ...

  14. Radiative left-right Dirac neutrino mass (United States)

    Ma, Ernest; Sarkar, Utpal


    We consider the conventional left-right gauge extension of the standard model of quarks and leptons without a scalar bidoublet. We study systematically how one-loop radiative Dirac neutrino masses may be obtained. In addition to two well-known cases from almost 30 years ago, we find two new scenarios with verifiable predictions.

  15. Giant melanoma of the left thumb

    NARCIS (Netherlands)

    Zeebregts, CJAM; Schraffordt Koops, H.

    A 74-year-old female patient is described with a giant melanoma of the left thenar and concomitant bilateral pulmonary metastases. Palliative treatment consisted of a two-staged procedure in order to save the limb from amputation. Firstly, perfusion with gamma-interferon, tumour necrosis

  16. Submitral Left Ventricular Aneurysm Associated with Thrombus

    African Journals Online (AJOL)


    Jan 1, 2018 ... She was given drugs for management of heart failure and ... treatment abroad. KEYWORDS: Ethiopia, heart failure, submitral aneurysm, thrombus. INTRODUCTION. Submitral left ventricle aneurysm is a rare cardiovascular disorder worldwide, but ... grade 2 pulmonary edema, and bilateral pleural effusion.

  17. Left-Right Symmetry at LHC

    CERN Document Server

    Maiezza, Alessio; Nesti, Fabrizio; Senjanovic, Goran


    We revisit the issue of the limit on the scale of Left-Right symmetry breaking. We focus on the minimal SU(2)_L x SU(2)_R x U(1)_B-L gauge theory with the seesaw mechanism and discuss the two possibilities of defining Left-Right symmetry as parity or charge conjugation. In the commonly adopted case of parity, we perform a complete numerical study of the quark mass matrices and the associated left and right mixing matrices without any assumptions usually made in the literature about the ratio of vacuum expectation values. We find that the usual lower limit on the mass of the right-handed gauge boson from the K mass difference, M_WR>2.5TeV, is subject to a possible small reduction due to the difference between right and left Cabibbo angles. In the case of charge conjugation the limit on M_WR is somewhat more robust. However, the more severe bounds from CP-violating observables are absent in this case. In fact, the free phases can also resolve the present mild discrepancy between the Standard Model and CP-violat...

  18. Left Dislocation: a typological overview | Westbury | Stellenbosch ...

    African Journals Online (AJOL)

    The Left Dislocation construction is a typologically universal phenomenon that has received detailed analysis, from both formal and functional perspectives, in a number of genetically and areally diverse languages. The present paper aims to provide a general overview of this cross-linguistic research with a concentration ...

  19. Left-forbidding cooperating distributed grammar systems

    Czech Academy of Sciences Publication Activity Database

    Goldefus, F.; Masopust, Tomáš; Meduna, A.


    Roč. 411, 40-42 (2010), s. 3661-3667 ISSN 0304-3975 Institutional research plan: CEZ:AV0Z10190503 Keywords : cooperating distributed grammar system * cooperating derivation mode * left-forbidding grammar * generative power * descriptional complexity Subject RIV: BA - General Mathematics Impact factor: 0.838, year: 2010

  20. Left Ventricular Thrombus among patients undergoing Transthoracic ...

    African Journals Online (AJOL)

    Objective: Left Ventricular Thrombus (LVT) is a well recognized complication of various cardiac conditions, particularly following an acute anterior myocardial infarction and in those with systolic congestive heart failure. Transthoracic echocardiography (TTE) remains the most common imaging modality to make the diagnosis ...

  1. Modern Democratic Left and Economic Crisis

    Directory of Open Access Journals (Sweden)

    Dubravko Radošević


    Full Text Available Political left, notably social democracy, implies acceptance of market economy and parliamentary democracy, as a political framework within which the interests of large sections of the population could be preserved. Does the modern political left have a chance to revive, after the global economic crisis? We believe it does. The core idea of social democracy is the idea of equality. It is the growing inequality that could help the return of social democracy. In Croatia, during transition, there was predominantly the process of neoliberalization, and the democratic left accepted a neoliberal economic agenda. Currently Croatia has a structural economic problem and deep recession. Due to the global crisis, the democratic left in Croatia should abandon economic neoliberalism. Macroeconomic policy decision-makers in Croatia should reject orthodox policies, and it is necessary to implement heterodox economic policies. There is an urgent need to achieve a new (postKeynesian consensus, a new combination of post-Keynesian economics and social democracy

  2. Left-sided portal hypertension revisited

    Directory of Open Access Journals (Sweden)

    Antonio Manenti


    Conclusions: In every case of left-sided portal hypertension, upper digestive endoscopy and close follow-up are recommended. Besides, computed tomography can demonstrate particular conditions directly favoring gastroesophageal varices, and aid in selection of the appropriate therapeutic decisions. [Arch Clin Exp Surg 2016; 5(4.000: 211-215

  3. Visual explorer facilitator's guide

    CERN Document Server

    Palus, Charles J


    Grounded in research and practice, the Visual Explorer™ Facilitator's Guide provides a method for supporting collaborative, creative conversations about complex issues through the power of images. The guide is available as a component in the Visual Explorer Facilitator's Letter-sized Set, Visual Explorer Facilitator's Post card-sized Set, Visual Explorer Playing Card-sized Set, and is also available as a stand-alone title for purchase to assist multiple tool users in an organization.

  4. Creativity, visualization abilities, and visual cognitive style. (United States)

    Kozhevnikov, Maria; Kozhevnikov, Michael; Yu, Chen Jiao; Blazhenkova, Olesya


    Despite the recent evidence for a multi-component nature of both visual imagery and creativity, there have been no systematic studies on how the different dimensions of creativity and imagery might interrelate. The main goal of this study was to investigate the relationship between different dimensions of creativity (artistic and scientific) and dimensions of visualization abilities and styles (object and spatial). In addition, we compared the contributions of object and spatial visualization abilities versus corresponding styles to scientific and artistic dimensions of creativity. Twenty-four undergraduate students (12 females) were recruited for the first study, and 75 additional participants (36 females) were recruited for an additional experiment. Participants were administered a number of object and spatial visualization abilities and style assessments as well as a number of artistic and scientific creativity tests. The results show that object visualization relates to artistic creativity and spatial visualization relates to scientific creativity, while both are distinct from verbal creativity. Furthermore, our findings demonstrate that style predicts corresponding dimension of creativity even after removing shared variance between style and visualization ability. The results suggest that styles might be a more ecologically valid construct in predicting real-life creative behaviour, such as performance in different professional domains. © 2013 The British Psychological Society.

  5. Successful treatment of bilateral visual loss caused by HIV ...

    African Journals Online (AJOL)

    Optic neuritis is not an uncommon diagnosis in HIV-infected patients, but it is rarely idiopathic. We report a case of a young HIV-infected woman who developed optic neuritis as her presenting manifestation of HIV infection. She had initially experienced sudden-onset right-sided painful visual loss; the left eye had become ...

  6. Astronauts Cooper and Conrad prepare cameras during visual acuity tests (United States)


    Astronauts L. Gordon Cooper Jr. (left), command pilot, and Charles Conrad Jr., pilot, the prime crew of the Gemini 5 space flight, prepare their cameras while aboard a C-130 aircraft flying near Laredo. The two astronauts are taking part in a series of visual acuity experiments to aid them in learning to identify known terrestrial features under controlled conditions.

  7. Left ventricular thrombi detected by Ga-67-DFO-DAS-fibrinogen imaging and two-dimentional echocardiography

    International Nuclear Information System (INIS)

    Sakoda, Satoru; Kinoshita, Masahiko; Suzuki, Teruyasu


    The capability of diagnosing left ventricular thrombi was compared by scintigraphy using Ga-67-DFO-DAS- fibrinogen (Ga: gallium, DFO: deferoxamine, DAS: dialdehyde starch) and two-dimensional echocardiography. Ga-67-DFO-DAS-fibrinogen scintigraphy and two-dimensional echocardiography were performed in 17 consecutive patients following myocardial infarction. In 11 of the 17 patients, left ventricular thrombi were visualized by Ga-67-DFO-DAS-fibrinogen scintigraphy, but only five of the 11 patients were found to have thrombi by two-dimensional echocardiography. In eight patients with inferior or posterior myocardial infarction, no left ventricular thrombi were detected by two-dimensional echocardiography, while in six of the eight patients, ventricular thrombi were visualized by Ga-67-DFO-DAS-fibrinogen scintigraphy. Among the patients receiving adequate anticoagulants from the episode, only three patients had thrombi. In contrast, the remaining eight patients with thrombi were either receiving no anticoagulants, or were receiving inadequate anticoagulant therapy. Ga-67-DFO-DAS-fibrinogen scintigraphy is a very simple and useful method for detecting thrombi in the left ventricle after myocardial infarction. It is more sensitive for detecting thrombi in the left ventricle after myocardial infarction. It is more sensitive for detecting thrombi in the ventricle than was two-dimensional echocardiography. With this method, we can demonstrate the preventive effect of anticoagulants for left ventricular thrombus formation following myocardial infarction. (author)

  8. Computational visual distinctness metric

    NARCIS (Netherlands)

    Martínez-Baena, J.; Toet, A.; Fdez-Vidal, X.R.; Garrido, A.; Rodríguez-Sánchez, R.


    A new computational visual distinctness metric based on principles of the early human visual system is presented. The metric is applied to quantify (1) the visual distinctness of targets in complex natural scenes and (2) the perceptual differences between compressed and uncompressed images. The new

  9. Programming Visual Basic 2005

    CERN Document Server

    Liberty, Jesse


    This information-packed guide helps you understand Visual Basic 2005, the next-generation release of the popular Visual Basic programming language. This book aims to make you immediately productive in creating Windows and web applications using Visual Basic 2005 and all of its tools. Perfect for experienced VB6 and novice programmers

  10. Visual attention and stability

    NARCIS (Netherlands)

    Mathot, Sebastiaan; Theeuwes, Jan


    In the present review, we address the relationship between attention and visual stability. Even though with each eye, head and body movement the retinal image changes dramatically, we perceive the world as stable and are able to perform visually guided actions. However, visual stability is not as

  11. Left ventricular function in chronic aortic regurgitation

    International Nuclear Information System (INIS)

    Iskandrian, A.S.; Hakki, A.H.; Manno, B.; Amenta, A.; Kane, S.A.


    Left ventricular performance was determined in 42 patients with moderate or severe aortic regurgitation during upright exercise by measuring left ventricular ejection fraction and volume with radionuclide ventriculography. Classification of the patients according to exercise tolerance showed that patients with normal exercise tolerance (greater than or equal to 7.0 minutes) had a significantly higher ejection fraction at rest (probability [p] . 0.02) and during exercise (p . 0.0002), higher cardiac index at exercise (p . 0.0008) and lower exercise end-systolic volume (p . 0.01) than did patients with limited exercise tolerance. Similar significant differences were noted in younger patients compared with older patients in ejection fraction at rest and exercise (both p . 0.001) and cardiac index at rest (p . 0.03) and exercise (p . 0.0005). The end-diastolic volume decreased during exercise in 60% of the patients. The patients with a decrease in volume were significantly younger and had better exercise tolerance and a larger end-diastolic volume at rest than did patients who showed an increase in volume. The mean corrected left ventricular end-diastolic radius/wall thickness ratio was significantly greater in patients with abnormal than in those with normal exercise reserve (mean +/- standard deviation 476 +/- 146 versus 377 +/- 92 mm Hg, p less than 0.05). Thus, in patients with chronic aortic regurgitation: 1) left ventricular systolic function during exercise was related to age, exercise tolerance and corrected left ventricular end-diastolic radius/wall thickness ratio, and 2) the end-diastolic volume decreased during exercise, especially in younger patients and patients with normal exercise tolerance or a large volume at rest

  12. Evaluation of global and regional left ventricular function obtained by quantitative gated SPECT using {sup 99m}Tc-tetrofosmin for left ventricular dysfunction

    Energy Technology Data Exchange (ETDEWEB)

    Ban, Kazunobu; Nakajima, Tohru; Iseki, Harukazu; Abe, Sumihisa; Handa, Shunnosuke; Suzuki, Yutaka [Tokai Univ., Isehara, Kanagawa (Japan). School of Medicine


    The quantitative gated SPECT (QGS) software is able to calculate LV volumes and visualize LV wall motion and perfusion throughout the cardiac cycle using an automatic edge detection algorithm of the left ventricle. We evaluated the reliability of global and regional LV function assessment derived from QGS by comparing it with the results from left ventriculo-cineangiography (LVG). In 20 patients with left ventricular dysfunction who underwent ECG gated {sup 99m}Tc-tetrofosmin SPECT, the end-diastolic volume (EDV), end-systolic volume (ESV) and ejection fraction (LVEF) were calculated. The QGS-assessed regional wall motion was determined using the cinematic display. QGS-derived EDV, ESV and LVEF correlated well with those by LVG (p<0.001 for each). There was a good correlation between wall motion score (WMS) derived from the QGS and the LVG (r=0.40, p<0.05). In some patients with extensive myocardial infarction, there was a discrepancy in the regional wall motion results between QGS and LVG. The ECG-gated SPECT using QGS is useful to evaluate global and regional LV functions in left ventricular dysfunction. (author)

  13. Non-retinotopic motor-visual recalibration to temporal lag

    Directory of Open Access Journals (Sweden)

    Masaki eTsujita


    Full Text Available Temporal order judgment between the voluntary motor action and its perceptual feedback is important in distinguishing between a sensory feedback which is caused by observer’s own action and other stimulus, which are irrelevant to that action. Prolonged exposure to fixed temporal lag between motor action and visual feedback recalibrates motor-visual temporal relationship, and consequently shifts the point of subjective simultaneity (PSS. Previous studies on the audio-visual temporal recalibration without voluntary action revealed that both low and high level processing are involved. However, it is not clear how the low and high level processings affect the recalibration to constant temporal lag between voluntary action and visual feedback. This study examined retinotopic specificity of the motor-visual temporal recalibration. During the adaptation phase, observers repeatedly pressed a key, and visual stimulus was presented in left or right visual field with a fixed temporal lag (0 or 200 ms. In the test phase, observers performed a temporal order judgment for observer’s voluntary keypress and test stimulus, which was presented in the same as or opposite to the visual field in which the stimulus was presented in the adaptation phase. We found that the PSS was shifted toward the exposed lag in both visual fields. These results suggest that the low visual processing, which is retinotopically specific, has minor contribution to the multimodal adaptation, and that the adaptation to shift the PSS mainly depends upon the high level processing such as attention to specific properties of the stimulus.

  14. Dissociative Disturbance in Hangul-Hanja Reading after a Left Posterior Occipital Lesion

    Directory of Open Access Journals (Sweden)

    Key-Chung Park


    Full Text Available Since the Korean language has two distinct writing systems, phonogram (Hangul and ideogram (Hanja: Chinese characters, alexia can present with dissociative disturbances in reading between the two systems. A 74-year-old right-handed man presented with a prominent reading impairment in Hangul with agraphia of both Hangul and Hanja after a left posterior occipital- parietal lesion. He could not recognize single syllable words and nonwords in Hangul, and visual errors were predominant in both Hanja reading and the Korean Boston Naming Test. In addition, he had difficulties in visuoperceptual tests including Judgment of Line Orientation, Hierarchical Navon figures, and complex picture scanning. These findings are consistent with the hypothesis that Hangul reading impairment results from a general visual perceptual deficit. However, this assumption cannot explain why performance on visually complex Hanja was better than performance on visually simple Hanja in our patient. In addition, the patient did not demonstrate higher accuracy on Hanja characters with fewer strokes than on words with more strokes. Thus, we speculate that the left posterior occipital area may be specialized for Hangul letter identification in this patient. This case demonstrates that Hangul-Hanja reading dissociation impairment can occur after occipital-parietal lesions.

  15. Assessment of stiffness of the hypertrophied left ventricle of bicyclists using left ventricular inflow Doppler velocimetry. (United States)

    Fagard, R; Van den Broeke, C; Bielen, E; Vanhees, L; Amery, A


    Sixteen male bicyclists and 16 control subjects were studied to assess whether the left ventricular hypertrophy of athletes is associated with changes in diastolic left ventricular function. The cyclists had a larger left ventricular internal diameter on echocardiography (55.2 versus 47.9 mm; p less than 0.001) and a disproportionate increase in wall thickness relative to the internal diameter (0.48 versus 0.41; p less than 0.01), indicating a mixed eccentric-concentric type of hypertrophy. Left ventricular inflow Doppler velocimetry showed similar results in athletes and control subjects for peak flow velocities in the atrial contraction phase (30 versus 32 cm/s; p = NS) and in the early diastolic rapid filling phase (71 versus 67 cm/s; p = NS). The similar ratio of both velocities, that is, 0.43 in the cyclists and 0.49 in the control subjects, suggests that left ventricular distensibility is unaltered in cyclists. It is concluded that the left ventricular hypertrophy observed in cyclists is not associated with changes in ventricular stiffness, as estimated from left ventricular inflow Doppler velocimetry.

  16. Prefrontal Neurons Represent Motion Signals from Across the Visual Field But for Memory-Guided Comparisons Depend on Neurons Providing These Signals. (United States)

    Wimmer, Klaus; Spinelli, Philip; Pasternak, Tatiana


    Visual decisions often involve comparisons of sequential stimuli that can appear at any location in the visual field. The lateral prefrontal cortex (LPFC) in nonhuman primates, shown to play an important role in such comparisons, receives information about contralateral stimuli directly from sensory neurons in the same hemisphere, and about ipsilateral stimuli indirectly from neurons in the opposite hemisphere. This asymmetry of sensory inputs into the LPFC poses the question of whether and how its neurons incorporate sensory information arriving from the two hemispheres during memory-guided comparisons of visual motion. We found that, although responses of individual LPFC neurons to contralateral stimuli were stronger and emerged 40 ms earlier, they carried remarkably similar signals about motion direction in the two hemifields, with comparable direction selectivity and similar direction preferences. This similarity was also apparent around the time of the comparison between the current and remembered stimulus because both ipsilateral and contralateral responses showed similar signals reflecting the remembered direction. However, despite availability in the LPFC of motion information from across the visual field, these "comparison effects" required for the comparison stimuli to appear at the same retinal location. This strict dependence on spatial overlap of the comparison stimuli suggests participation of neurons with localized receptive fields in the comparison process. These results suggest that while LPFC incorporates many key aspects of the information arriving from sensory neurons residing in opposite hemispheres, it continues relying on the interactions with these neurons at the time of generating signals leading to successful perceptual decisions. Visual decisions often involve comparisons of sequential visual motion that can appear at any location in the visual field. We show that during such comparisons, the lateral prefrontal cortex (LPFC) contains

  17. Bimanual proprioceptive performance differs for right- and left-handed individuals. (United States)

    Han, Jia; Waddington, Gordon; Adams, Roger; Anson, Judith


    It has been proposed that asymmetry between the upper limbs in the utilization of proprioceptive feedback arises from functional differences in the roles of the preferred and non-preferred hands during bimanual tasks. The present study investigated unimanual and bimanual proprioceptive performance in right- and left-handed young adults with an active finger pinch movement discrimination task. With visual information removed, participants were required to make absolute judgments about the extent of pinch movements made to physical stops, either by one hand, or by both hands concurrently, with the sequence of presented movement extents varied randomly. Discrimination accuracy scores were derived from participants' responses using non-parametric signal detection analysis. Consistent with previous findings, a non-dominant hand/hemisphere superiority effect was observed, where the non-dominant hands of right- and left-handed individuals performed overall significantly better than their dominant hands. For all participants, bimanual movement discrimination scores were significantly lower than scores obtained in the unimanual task. However, the magnitude of the performance reduction, from the unimanual to the bimanual task, was significantly greater for left-handed individuals. The effect whereby bimanual proprioception was disproportionately affected in left-handed individuals could be due to enhanced neural communication between hemispheres in left-handed individuals leading to less distinctive separation of information obtained from the two hands in the cerebral cortex. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  18. Evaluatıng the effectiveness of frozen shoulder treatment on the right and left sides. (United States)

    Alptekin, Hasan Kerem; Aydın, Tuğba; İflazoğlu, Enes Serkan; Alkan, Mirsad


    [Purpose] To evaluate treatments with interferential current, hot pack, ultrasound therapy, stretching, strengthening and range-of-motion exercises, comparing between the right and left shoulders in terms of pain and functional capacity in patients with frozen shoulder. This was a retrospective study. [Subjects and Methods] Sixty-four patients (34 right side, 30 left side) were treated with interferential current and hot pack application for 20 min each, ultrasound therapy for 3 min, regular range-of-motion exercises, stretching exercises, strengthening with a Theraband in all directions and post-exercise proprioceptive neuromuscular facilitation techniques. All cases were evaluated with visual analogue scales for pain, passive and active range of motion, Constant score, and the shoulder disability questionnaire, at baseline and 7 and 12 weeks after baseline. [Results] Marked improvement was noted in all patients in both right and left sides after treatment, and at 7 and 12 weeks of follow-up compared with baseline. There was no significant difference between the right and left shoulder groups, in all outcome measures. [Conclusion] The combination of physical therapy, exercise, and manual techniques is effective in treating frozen shoulder. The location of the lesion in the right or left shoulder does not, in itself, affect the prognosis or treatment outcome.

  19. Opposite brain laterality in analogous auditory and visual tests. (United States)

    Oltedal, Leif; Hugdahl, Kenneth


    Laterality for language processing can be assessed by auditory and visual tasks. Typically, a right ear/right visual half-field (VHF) advantage is observed, reflecting left-hemispheric lateralization for language. Historically, auditory tasks have shown more consistent and reliable results when compared to VHF tasks. While few studies have compared analogous tasks applied to both sensory modalities for the same participants, one such study by Voyer and Boudreau [(2003). Cross-modal correlation of auditory and visual language laterality tasks: a serendipitous finding. Brain Cogn, 53(2), 393-397] found opposite laterality for visual and auditory language tasks. We adapted an experimental paradigm based on a dichotic listening and VHF approach, and applied the combined language paradigm in two separate experiments, including fMRI in the second experiment to measure brain activation in addition to behavioural data. The first experiment showed a right-ear advantage for the auditory task, but a left half-field advantage for the visual task. The second experiment, confirmed the findings, with opposite laterality effects for the visual and auditory tasks. In conclusion, we replicate the finding by Voyer and Boudreau (2003) and support their interpretation that these visual and auditory language tasks measure different cognitive processes.

  20. PICTORIAL ESSAY Is anomalous origin of the left vertebral artery ...

    African Journals Online (AJOL)

    The incidence of anomalous origin of the left vertebral artery from the aortic arch ranges between 1% and 5.8%.1,2 This anomaly has important implications for thoracic surgery and interventional procedures. The left vertebral artery may originate from: • the left common carotid artery. • the root of the left subclavian artery ...

  1. Left bronchial artery arising from a replaced left hepatic artery in a patient with massive hemoptysis

    Energy Technology Data Exchange (ETDEWEB)

    Khil, Eun Kyung; Lee, Jae Myung [Dept. of Radiology, Soonchunhyang University College of Medicine, Bucheon Hospital, Bucheon (Korea, Republic of)


    A 70-year-old man with a 3-year history of bronchiectasis presented with massive hemoptysis that had lasted for 3 days. In our attempt to perform bronchial artery embolization, upper abdominal angiography was required to locate the left bronchial artery, which in this case was of anomalous origin, arising from a replaced left hepatic artery, which arose from the left gastric artery-a very unusual anatomical variant. We performed embolization with polyvinyl alcohol particles, and the patient's symptoms resolved completely, with no additional complications after conservative treatment.

  2. Python data visualization cookbook

    CERN Document Server

    Milovanovic, Igor


    This book is written in a Cookbook style targeted towards an advanced audience. It covers the advanced topics of data visualization in Python.Python Data Visualization Cookbook is for developers that already know about Python programming in general. If you have heard about data visualization but you don't know where to start, then this book will guide you from the start and help you understand data, data formats, data visualization, and how to use Python to visualize data.You will need to know some general programming concepts, and any kind of programming experience will be helpful, but the co

  3. Visualization system on ITBL

    International Nuclear Information System (INIS)

    Suzuki, Yoshio


    Visualization systems PATRAS/ITBL and AVS/ITBL, which are based on visualization software PATRAS and AVS/Express respectively, have been developed on a global, heterogeneous computing environment, Information Technology Based Laboratory (ITBL). PATRAS/ITBL allows for real-time visualization of the numerical results acquired from coupled multi-physics numerical simulations, executed on different hosts situated in remote locations. AVS/ITBL allow for post processing visualization. The scientific data located in remote sites may be selected and visualized on a web browser installed in a user terminal. The global structure and main functions of these systems are presented. (author)

  4. Professional Visual Studio 2010

    CERN Document Server

    Randolph, Nick; Anderson, Chris


    A must-have guide that covers all the new features of Visual Studio 2010. Visual Studio allows you to create and manage programming projects for the Windows platform, and the new 2010 version has undergone a major overhaul comprised of significant changes. Written by an author team of veteran programmers and developers, Professional Visual Studio 2010 gets you quickly up to speed on what you can expect from the newest version of Visual Studio. This book's first section is dedicated to familiarizing you with the core aspects of Visual Studio 2010. Everything you need is contained in the first f

  5. Visual Semiotics & Uncertainty Visualization: An Empirical Study. (United States)

    MacEachren, A M; Roth, R E; O'Brien, J; Li, B; Swingley, D; Gahegan, M


    This paper presents two linked empirical studies focused on uncertainty visualization. The experiments are framed from two conceptual perspectives. First, a typology of uncertainty is used to delineate kinds of uncertainty matched with space, time, and attribute components of data. Second, concepts from visual semiotics are applied to characterize the kind of visual signification that is appropriate for representing those different categories of uncertainty. This framework guided the two experiments reported here. The first addresses representation intuitiveness, considering both visual variables and iconicity of representation. The second addresses relative performance of the most intuitive abstract and iconic representations of uncertainty on a map reading task. Combined results suggest initial guidelines for representing uncertainty and discussion focuses on practical applicability of results.

  6. Detection and characterization of left Ventricular Thrombi by MRT compared to Transthoracic Echocardiography

    International Nuclear Information System (INIS)

    Bruder, O.; Jochims, M.; Sabin, G.V.; Waltering, K.U.; Hunhold, P.; Narin, B.; Barkhausen, J.


    Purpose: Transthoracic echocardiography is the routine diagnostic procedure in assessing patients with left ventricular thrombi, but is limited by the acoustic window and poor contrast between thrombus and adjacent myocardium. This study evaluates the role of cardiac MRI in the detection of left ventricular thrombi in patients with chronic myocardial infarction compared to standard transthoracic echocardiography. Materials and Methods: In 82 patients (55 men and 27 women, age 36 to 79 years, median 59±11 years) who suffered a myocardial infarction more than 6 months earlier, transthoracic echocardiography and MRI were performed. The MRI protocol included steady state cine imaging (true FISP: TR 3.0 ms, TE 1.5 ms, FA 65 ) in standard long and short axis orientation and contrast-enhanced imaging using a 3D IR-FLASH sequence with long inversion time (TR 4 ms; TE 1.43 ms, FA 10 , TI 300 ms) early, and a 2D IR-FLASH sequence with optimized inversion time (TR 8 ms, TE 4.3 ms, FA 20 , TI 180-280 ms) late after administration of gadolinium. Results: Transthoracic echocardiography depicted 12 thrombi. Contrast-enhanced MRI confirmed these 12 thrombi and detected 23 additional thrombi. With the exception of 2 very small apical thrombi only visible on contrast-enhanced MRI images, spherical thrombi were diagnosed by both techiques, whereas only contrast-enhanced MRI was able to visualize mural thrombi. Left ventricular thrombi were more frequently diagnosed in patients with moderate to severe impairment of the left ventricular systolic function, 32/42 (76%), or in patients with left ventricular aneurysms, 21/24 (84%). Conclusion: Contrast-enhanced MRI is mostly superior to transthoracic echocardiography in diagnosing mural left ventricular thrombi in patients who had suffered a myocardial infarction. Intracavitray thrombi are mor frequently found in patients with impaired regional and global left ventricular function. (orig.)

  7. Independent representations of verbs and actions in left lateral temporal cortex. (United States)

    Peelen, Marius V; Romagno, Domenica; Caramazza, Alfonso


    Verbs and nouns differ not only on formal linguistic grounds but also in what they typically refer to: Verbs typically refer to actions, whereas nouns typically refer to objects. Prior neuroimaging studies have revealed that regions in the left lateral temporal cortex (LTC), including the left posterior middle temporal gyrus (pMTG), respond selectively to action verbs relative to object nouns. Other studies have implicated the left pMTG in action knowledge, raising the possibility that verb selectivity in LTC may primarily reflect action-specific semantic features. Here, using functional neuroimaging, we test this hypothesis. Participants performed a simple memory task on visually presented verbs and nouns that described either events (e.g., "he eats" and "the conversation") or states (e.g., "he exists" and "the value"). Verb-selective regions in the left pMTG and the left STS were defined in individual participants by an independent localizer contrast between action verbs and object nouns. Both regions showed equally strong selectivity for event and state verbs relative to semantically matched nouns. The left STS responded more to states than events, whereas there was no difference between states and events in the left pMTG. Finally, whole-brain group analysis revealed that action verbs, relative to state verbs, activated a cluster in pMTG that was located posterior to the verb-selective pMTG clusters. Together, these results indicate that verb selectivity in LTC is independent of action representations. We consider other differences between verbs and nouns that may underlie verb selectivity in LTC, including the verb property of predication.

  8. Halftone visual cryptography. (United States)

    Zhou, Zhi; Arce, Gonzalo R; Di Crescenzo, Giovanni


    Visual cryptography encodes a secret binary image (SI) into n shares of random binary patterns. If the shares are xeroxed onto transparencies, the secret image can be visually decoded by superimposing a qualified subset of transparencies, but no secret information can be obtained from the superposition of a forbidden subset. The binary patterns of the n shares, however, have no visual meaning and hinder the objectives of visual cryptography. Extended visual cryptography [1] was proposed recently to construct meaningful binary images as shares using hypergraph colourings, but the visual quality is poor. In this paper, a novel technique named halftone visual cryptography is proposed to achieve visual cryptography via halftoning. Based on the blue-noise dithering principles, the proposed method utilizes the void and cluster algorithm [2] to encode a secret binary image into n halftone shares (images) carrying significant visual information. The simulation shows that the visual quality of the obtained halftone shares are observably better than that attained by any available visual cryptography method known to date.

  9. EEG Correlates of Preparatory Orienting, Contextual Updating, and Inhibition of Sensory Processing in Left Spatial Neglect. (United States)

    Lasaponara, Stefano; D'Onofrio, Marianna; Pinto, Mario; Dragone, Alessio; Menicagli, Dario; Bueti, Domenica; De Lucia, Marzia; Tomaiuolo, Francesco; Doricchi, Fabrizio


    Studies with event-related potentials have highlighted deficits in the early phases of orienting to left visual targets in right-brain-damaged patients with left spatial neglect (N+). However, brain responses associated with preparatory orienting of attention, with target novelty and with the detection of a match/mismatch between expected and actual targets (contextual updating), have not been explored in N+. Here in a study in healthy humans and brain-damaged patients of both sexes we demonstrate that frontal activity that reflects supramodal mechanisms of attentional orienting (Anterior Directing Attention Negativity, ADAN) is entirely spared in N+. In contrast, posterior responses that mark the early phases of cued orienting (Early Directing Attention Negativity, EDAN) and the setting up of sensory facilitation over the visual cortex (Late Directing Attention Positivity, LDAP) are suppressed in N+. This uncoupling is associated with damage of parietal-frontal white matter. N+ also exhibit exaggerated novelty reaction to targets in the right side of space and reduced novelty reaction for those in the left side (P3a) together with impaired contextual updating (P3b) in the left space. Finally, we highlight a drop in the amplitude and latency of the P1 that over the left hemisphere signals the early blocking of sensory processing in the right space when targets occur in the left one: this identifies a new electrophysiological marker of the rightward attentional bias in N+. The heterogeneous effects and spatial biases produced by localized brain damage on the different phases of attentional processing indicate relevant functional independence among their underlying neural mechanisms and improve the understanding of the spatial neglect syndrome. SIGNIFICANCE STATEMENT Our investigation answers important questions: are the different components of preparatory orienting (EDAN, ADAN, LDAP) functionally independent in the healthy brain? Is preparatory orienting of

  10. Dyscalculia, dysgraphia, and left-right confusion from a left posterior peri-insular infarct. (United States)

    Bhattacharyya, S; Cai, X; Klein, J P


    The Gerstmann syndrome of dyscalculia, dysgraphia, left-right confusion, and finger agnosia is generally attributed to lesions near the angular gyrus of the dominant hemisphere. A 68-year-old right-handed woman presented with sudden difficulty completing a Sudoku grid and was found to have dyscalculia, dysgraphia, and left-right confusion. Magnetic resonance imaging (MRI) showed a focus of abnormal reduced diffusivity in the left posterior insula and temporoparietal operculum consistent with acute infarct. Gerstmann syndrome from an insular or peri-insular lesion has not been described in the literature previously. Pathological and functional imaging studies show connections between left posterior insular region and inferior parietal lobe. We postulate that the insula and operculum lesion disrupted key functional networks resulting in a pseudoparietal presentation.

  11. Dyscalculia, Dysgraphia, and Left-Right Confusion from a Left Posterior Peri-Insular Infarct

    Directory of Open Access Journals (Sweden)

    S. Bhattacharyya


    Full Text Available The Gerstmann syndrome of dyscalculia, dysgraphia, left-right confusion, and finger agnosia is generally attributed to lesions near the angular gyrus of the dominant hemisphere. A 68-year-old right-handed woman presented with sudden difficulty completing a Sudoku grid and was found to have dyscalculia, dysgraphia, and left-right confusion. Magnetic resonance imaging (MRI showed a focus of abnormal reduced diffusivity in the left posterior insula and temporoparietal operculum consistent with acute infarct. Gerstmann syndrome from an insular or peri-insular lesion has not been described in the literature previously. Pathological and functional imaging studies show connections between left posterior insular region and inferior parietal lobe. We postulate that the insula and operculum lesion disrupted key functional networks resulting in a pseudoparietal presentation.

  12. Left ventricular non-compaction cardiomyopathy and left ventricular assist device: a word of caution. (United States)

    Kornberger, A; Stock, U A; Risteski, P; Beiras Fernandez, A


    In patients with left ventricular non-compaction (LVNC), implantation of a left ventricular assist device (LVAD) may be performed as a bridge to transplantation. In this respect, the particular characteristics of the left ventricular myocardium may represent a challenge. We report a patient with LVNC who required urgent heart transplantation for inflow cannula obstruction nine months after receiving a LVAD. LVAD parameters, echocardiography and examination of the explanted heart suggested changes of left ventricular configuration brought about by LVAD support as the most likely cause of inflow cannula obstruction. We conclude that changes experienced by non-compacted myocardium during LVAD support may give rise to inflow cannula obstruction and flow reduction. Presence of LVNC mandates tight surveillance for changes in LV configuration and LVAD flow characteristics and may justify urgent transplantation listing status.

  13. [Left postpneumonectomy syndrome: early endoscopic treatment]. (United States)

    Rombolá, Carlos A; León Atance, Pablo; Honguero Martínez, Antonio Francisco; Rueda Martínez, Juan Luis; Núñez Ares, Ana; Vizcaya Sánchez, Manuel


    Postpneumonectomy syndrome is characterized by postoperative bronchial obstruction caused by mediastinal shift. The syndrome is well documented in the medical literature as a late complication of right pneumonectomy; however, it rarely occurs following resection of the left lung, and only 10 cases have been published. The pathophysiology, clinical manifestations, prognosis, and treatment are similar for both sides of the lung. We present the case of an adult patient who underwent left pneumonectomy and developed postpneumonectomy syndrome 15 months later. Stenosis of the intermediate bronchus occurred between the vertebral body and the right pulmonary artery. Endoscopic treatment with a self-expanding metal stent was successful, and complete remission was observed over the 6 months of follow-up.

  14. Left-right symmetric electroweak models

    International Nuclear Information System (INIS)

    Olness, F.I.


    We present a critical analysis of the spontaneous symmetry breaking and the Higgs sector of the conventional SU(2) L circle-times SU(2) R circle-times U(1) B-L left-right symmetric theory involving bi-doublet and triplet Higgs fields. We examine the phenomenological constraints imposed on the minimization of the Higgs potential arising from experimental observations, and explore the resulting consequences including the problem of ''fine- tuning'' arising from the hierarchy of mass scales involved. We show that it is non-trivial to satisfy all of these constraints. We contrast the benefits of this general class left-right models against the required ''fine-tuning'' necessary to force the phenomenology to conform to experimental fact. 17 refs., 1 fig

  15. Minimal Left-Right Symmetric Dark Matter. (United States)

    Heeck, Julian; Patra, Sudhanwa


    We show that left-right symmetric models can easily accommodate stable TeV-scale dark matter particles without the need for an ad hoc stabilizing symmetry. The stability of a newly introduced multiplet either arises accidentally as in the minimal dark matter framework or comes courtesy of the remaining unbroken Z_{2} subgroup of B-L. Only one new parameter is introduced: the mass of the new multiplet. As minimal examples, we study left-right fermion triplets and quintuplets and show that they can form viable two-component dark matter. This approach is, in particular, valid for SU(2)×SU(2)×U(1) models that explain the recent diboson excess at ATLAS in terms of a new charged gauge boson of mass 2 TeV.

  16. Total agenesis of the left pericardium

    Directory of Open Access Journals (Sweden)

    J. Glauco Lobo Fº


    Full Text Available This is the report of a 46-year-old patient with the preoperative diagnosis of an atrial septal defect (ASD of the ostium secudum type. After sternectomy, partial agenesis of the left pericardium was diagnosed. It is our opinion that, if the radiographic picture is suggestive of this entity, a clinical search for cardiopulmonary anomalies should be performed, because the majority of these associated anomalies can and should be surgically corrected.

  17. The New Arab Left and 1967

    DEFF Research Database (Denmark)

    Haugbølle, Sune


    In Arab political culture, the Naksa of 1967 had a number of watershed effects. Scholars have paid a lot of attention to the decline of secular Arab nationalism and the concurrent rise of Islamism. Much less research has been done on the way 1967 spurred radical left organizations, also known as ...... moment that followed. This moment has had a lasting impact on Arab political culture and is being re-interpreted in interesting ways today by Arab revolutionaries post-2011....

  18. Coronary Anomalies: Left Main Coronary Artery Aneurysm


    Varda, Rajsekhar; Chitimilla, Santosh Kumar; Lalani, Aslam


    Coronary artery aneurysm is one of the rarest anomalies that we see in our medical practice and they are mostly associated with obstructive lesions due to atherosclerotic changes. Management of these aneurysm patients (conservative or surgical repair) usually depends on obstructive lesions and associated symptoms. We are presenting a case of left main aneurysm measuring around 1 4 × 2 8  mm with other obstructive leisons. It was treated with surgical repair in view of obstructive lesions and ...

  19. Coronary Anomalies: Left Main Coronary Artery Aneurysm

    Directory of Open Access Journals (Sweden)

    Rajsekhar Varda


    Full Text Available Coronary artery aneurysm is one of the rarest anomalies that we see in our medical practice and they are mostly associated with obstructive lesions due to atherosclerotic changes. Management of these aneurysm patients (conservative or surgical repair usually depends on obstructive lesions and associated symptoms. We are presenting a case of left main aneurysm measuring around 14×28 mm with other obstructive leisons. It was treated with surgical repair in view of obstructive lesions and symptoms.

  20. Primary malignant fibrous histiocytoma involving the left pulmonary vein presenting as a left atrial tumor

    Directory of Open Access Journals (Sweden)

    Saikat Bandyopadhyay


    Full Text Available A 35-year-old woman presented with 4 months history of progressively increasing intermittent dyspnea and hemoptysis. Transthoracic echocardiography revealed a loculated mass in the left atrium (LA. A provisional diagnosis of LA myxoma was made. Intraoperatively the tumor was found extending into and closely adherent to the left pulmonary vein and could not be completely cleared off from the pulmonary venous wall. The histopathological examination of the tumor revealed it to be a myxoid malignant fibrous histiocytoma.

  1. Implantation of left ventricular assist device in a patient with left ventricular non-compaction. (United States)

    Balsara, Keki R; Bierhals, Andrew; Vader, Justin; Pasque, Michael K; Itoh, Aki


    Left ventricular noncompaction (LVNC) may result in systolic left ventricular (LV) failure resulting in the need for heart transplantation. LV assist devices (LVAD) have been used to bridge these patients to transplantation; however, the extensive trabeculations found in these patients predispose them to thromboembolic events and pump thrombosis. We describe a patient with LVNC in whom an aggressive surgical approach was used to debride the LV cavity of trabeculations to successfully implant an LVAD. © 2017 Wiley Periodicals, Inc.

  2. Facilitating memory for novel characters by reducing neural repetition suppression in the left fusiform cortex. (United States)

    Xue, Gui; Mei, Leilei; Chen, Chuansheng; Lu, Zhong-Lin; Poldrack, Russell A; Dong, Qi


    The left midfusiform and adjacent regions have been implicated in processing and memorizing familiar words, yet its role in memorizing novel characters has not been well understood. Using functional MRI, the present study examined the hypothesis that the left midfusiform is also involved in memorizing novel characters and spaced learning could enhance the memory by enhancing the left midfusiform activity during learning. Nineteen native Chinese readers were scanned while memorizing the visual form of 120 Korean characters that were novel to the subjects. Each character was repeated four times during learning. Repetition suppression was manipulated by using two different repetition schedules: massed learning and spaced learning, pseudo-randomly mixed within the same scanning session. Under the massed learning condition, the four repetitions were consecutive (with a jittered inter-repetition interval to improve the design efficiency). Under the spaced learning condition, the four repetitions were interleaved with a minimal inter-repetition lag of 6 stimuli. Spaced learning significantly improved participants' performance during the recognition memory test administered one hour after the scan. Stronger left midfusiform and inferior temporal gyrus activities during learning (summed across four repetitions) were associated with better memory of the characters, based on both within- and cross-subjects analyses. Compared to massed learning, spaced learning significantly reduced neural repetition suppression and increased the overall activities in these regions, which were associated with better memory for novel characters. These results demonstrated a strong link between cortical activity in the left midfusiform and memory for novel characters, and thus challenge the visual word form area (VWFA) hypothesis. Our results also shed light on the neural mechanisms of the spacing effect in memorizing novel characters.

  3. Perception of active head rotation in patients with severe left unilateral spatial neglect. (United States)

    Kaibe, Shinobu; Okita, Manabu; Kaba, Hideto


    Unilateral spatial neglect is a common neurological syndrome following predominantly right hemisphere damage, and is characterized by a failure to perceive and report stimuli in the contralesional side of space. To test the reference shift hypothesis that contralesional spatial neglect in right-brain-damaged patients is attributed to a rightward deviation of the egocentric reference frame, we measured the final angular position to which controls and left-side neglect patients actively turned their head toward the left in response to a verbal instruction given from each of three locations-right, left, and front-in two conditions, with and without visual feedback. When neglect patients were asked to "look straight ahead", they deviated about 30° toward the right in the eyes-open condition. However, the rightward deviation was markedly reduced in the eyes-closed condition. Regardless of visual feedback, there was no significant difference between controls and neglect patients in the final angular position of active head rotation when the verbal instruction came from the subject's left or front side; however, the final angular position was significantly smaller in the neglect patients than in the controls when the verbal instruction was given from the right. These results support the contention that cervico-vestibular stimulation during active head rotation restores spatial remapping and sensori-motor correlations and so improves neglect without affecting the position of the egocentric reference; however, once left-side neglect patients respond to verbal instruction from the right side, they are unable to disengage attention from the hemispace, and the performance of head rotation is disturbed. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. Enhancing motor network activity using real-time functional MRI neurofeedback of left premotor cortex

    Directory of Open Access Journals (Sweden)

    Theo Ferreira Marins


    Full Text Available Neurofeedback by functional Magnetic Resonance Imaging (fMRI is a technique of potential therapeutic relevance that allows individuals to be aware of their own neurophysiological responses and to voluntarily modulate the activity of specific brain regions, such as the premotor cortex (PMC, important for motor recovery after brain injury. We investigated (i whether healthy human volunteers are able to up-regulate the activity of the left PMC during a right hand finger tapping motor imagery (MI task while receiving continuous fMRI-neurofeedback, and (ii whether successful modulation of brain activity influenced non-targeted motor control regions. During the MI task, participants of the neurofeedback group (NFB received ongoing visual feedback representing the level of fMRI responses within their left PMC. Control (CTL group participants were shown similar visual stimuli, but these were non-contingent on brain activity. Both groups showed equivalent levels of behavioral ratings on arousal and motor imagery, before and during the fMRI protocol. In the NFB, but not in CLT group, brain activation during the last run compared to the first run revealed increased activation in the left PMC. In addition, the NFB group showed increased activation in motor control regions extending beyond the left PMC target area, including the supplementary motor area, basal ganglia and cerebellum. Moreover, in the last run, the NFB group showed stronger activation in the left PMC/inferior frontal gyrus when compared to the CTL group. Our results indicate that modulation of PMC and associated motor control areas can be achieved during a single neurofeedback-fMRI session. These results contribute to a better understanding of the underlying mechanisms of MI-based neurofeedback training, with direct implications for rehabilitation strategies in severe brain disorders, such as stroke.

  5. Features of Dynamic Visual Acuity and Patterns in Target Tracking Observed in Volleyball Players


    石垣, 尚男


    Volleyball players showed superior dynamic visual acuity when tracking a target moving from right to left. Using an eye mark recorder, patterns in target tracking were compared between volleyball players who showed especially high dynamic visual acuity and non-players of sport who showed especially low dynamic visual acuity. It was found that the width of eye movement was broad in the volleyball players while that in the non-players of sport was narrow.

  6. Rehabilitation of Visual and Perceptual Dysfunction after Severe Traumatic Brain Injury (United States)


    mobility .5-7 a c b 4 Figure 1 a) The binocular visual field of a patient with left HH as measured by Goldmann Perimetry with V4e stimulus...Bisection test 27 and Bells test 28), best corrected visual acuity 6/15 (20/50) or better in each eye, no strabismus (when wearing spectacles...AD_________________ Award Number: W81XWH-11-2-0082 TITLE: Rehabilitation of Visual and Perceptual Dysfunction after Severe

  7. Pulmonary Hypertension secondary to Left Heart Disease. (United States)

    Kabbach, Ghazal; Mukherjee, Debabrata


    Pulmonary hypertension (PH) related to left heart disease (LHD) is the most common form of PH, accounting for more than two third of all PH cases. The hemodynamic abnormalities seen in PH-LHD are complex, and there are currently minimal evidence-based recommendations for the management of PH-LHD. While it is accepted that PH in the context of left heart disease is a marker of worse prognosis, it remains unclear whether its primary treatment is beneficial or harmful. In this article, we discuss the prevalence and significance of PH in patients with heart failure (HF) with reduced ejection fraction (HFrEF) as well as HF with preserved ejection fraction (HFpEF), and those with valvular heart disease and provide insights into the complex pathophysiology of cardiopulmonary interrelationship in individuals with PH due to left heart disease. Furthermore, we provide a framework for diagnostic testing and an approach to optimal management of these complex patients based on current European Society of Cardiology (ESC) guidelines. Copyright© Bentham Science Publishers; For any queries, please email at

  8. Anomalous Origin of Left Circumflex Artery (United States)

    Çitaku, Hajdin; Kamberi, Lulzim; Gorani, Daut; Koçinaj, Dardan; Krasniqi, Xhevdet


    Introduction: The coronary anatomic variation of the left circumflex artery (LCx) is considered as the most common anatomic variation with a separate ostium from the right sinus, and very unusual variation as a proximal branch of right coronary artery (RCA). Case report: We report two cases, the first case is a 64-year-old man with chest pain and with history of hypertension, obesity, dyslipidemia and current smoker, and the second case is a 67-year-old who presented to the emergency department with chest pain and with a past medical history of arterial hypertension and type 2 diabetes mellitus. In the coronarography of the first case is detected an ectopic left circumflex coronary artery from the right coronary sinus with stenotic changes in RCA and LCx. The second case in the coronary angiography revealed an ectopic left circumflex coronary artery from the proximal part of the right coronary artery with stenotic changes in LAD, RCA and LCx. Based on guidelines for revascularization our patients successfully underwent treatment procedures. We present two cases that because of the atherosclerotic coronary artery disease leads to the need of coronarography find out the presence of coronary artery anomalies. Conclusion: During the coronarography we should think about coronary artery anomaly or missing artery knowing that type of these anomalies, considering that may be a contributing factor in the development of the atherosclerosis determines the method of the treatment. PMID:26843740

  9. Pulmonary hypertension due to left heart disease. (United States)

    Berthelot, Emmanuelle; Bailly, Minh Tam; Hatimi, Safwane El; Robard, Ingrid; Rezgui, Hatem; Bouchachi, Amir; Montani, David; Sitbon, Olivier; Chemla, Denis; Assayag, Patrick

    Pulmonary hypertension due to left heart disease, also known as group 2 pulmonary hypertension according to the European Society of Cardiology/European Respiratory Society classification, is the most common cause of pulmonary hypertension. In patients with left heart disease, the development of pulmonary hypertension favours right heart dysfunction, which has a major impact on disease severity and outcome. Over the past few years, this condition has been considered more frequently. However, epidemiological studies of group 2 pulmonary hypertension are less exhaustive than studies of other causes of pulmonary hypertension. In group 2 patients, pulmonary hypertension may be caused by an isolated increase in left-sided filling pressures or by a combination of this condition with increased pulmonary vascular resistance, with an abnormally high pressure gradient between arteries and pulmonary veins. A better understanding of the conditions underlying pulmonary hypertension is of key importance to establish a comprehensive diagnosis, leading to an adapted treatment to reduce heart failure morbidity and mortality. In this review, epidemiology, mechanisms and diagnostic approaches are reviewed; then, treatment options and future approaches are considered. Copyright © 2017. Published by Elsevier Masson SAS.

  10. Left-Deviating Prism Adaptation in Left Neglect Patient: Reflexions on a Negative Result

    Directory of Open Access Journals (Sweden)

    Jacques Luauté


    Full Text Available Adaptation to right-deviating prisms is a promising intervention for the rehabilitation of patients with left spatial neglect. In order to test the lateral specificity of prism adaptation on left neglect, the present study evaluated the effect of left-deviating prism on straight-ahead pointing movements and on several classical neuropsychological tests in a group of five right brain-damaged patients with left spatial neglect. A group of healthy subjects was also included for comparison purposes. After a single session of exposing simple manual pointing to left-deviating prisms, contrary to healthy controls, none of the patients showed a reliable change of the straight-ahead pointing movement in the dark. No significant modification of attentional paper-and-pencil tasks was either observed immediately or 2 hours after prism adaptation. These results suggest that the therapeutic effect of prism adaptation on left spatial neglect relies on a specific lateralized mechanism. Evidence for a directional effect for prism adaptation both in terms of the side of the visuomanual adaptation and therefore possibly in terms of the side of brain affected by the stimulation is discussed.

  11. Face-sex categorization is better above fixation than below: Evidence from the reach-to-touch paradigm. (United States)

    Quek, Genevieve L; Finkbeiner, Matthew


    The masked congruence effect (MCE) elicited by nonconsciously presented faces in a sex-categorization task has recently been shown to be sensitive to the effects of attention. Here we investigated how spatial location along the vertical meridian modulates the MCE for face-sex categorization. Participants made left and right reaching movements to classify the sex of a target face that appeared either immediately above or below central fixation. The target was preceded by a masked prime face that was either congruent (i.e., same sex) or incongruent (i.e., opposite sex) with the target. In the reach-to-touch paradigm, participants typically classify targets more efficiently (i.e., their finger heads in the correct direction earlier and faster) on congruent than on incongruent trials. We observed an upper-hemifield advantage in the time course of this MCE, such that primes affected target classification sooner when they were presented in the upper visual field (UVF) rather than the lower visual field (LVF). Moreover, we observed a differential benefit of attention between the vertical hemifields, in that the MCE was dependent on the appropriate allocation of spatial attention in the LVF, but not the UVF. Taken together, these behavioral findings suggest that the processing of faces qua faces (e.g., sex-categorization) is more robust in upper-hemifield locations.

  12. A Ventral Visual Stream Reading Center Independent of Sensory Modality and Visual Experience

    Directory of Open Access Journals (Sweden)

    Lior Reich


    Full Text Available The Visual Word Form Area (VWFA is a ventral-temporal-visual area that develops expertise for visual reading. It encodes letter-strings irrespective of case, font, or location in the visual-field, with striking anatomical reproducibility across individuals. In the blind, reading can be achieved using Braille, with a comparable level-of-expertise to that of sighted readers. We investigated which area plays the role of the VWFA in the blind. One would expect it to be at either parietal or bilateral occipital cortex, reflecting the tactile nature of the task and crossmodal plasticity, respectively. However, according to the notion that brain areas are task specific rather than sensory-modality specific, we predicted recruitment of the left-hemispheric VWFA, identically to the sighted and independent of visual experience. Using fMRI we showed that activation during Braille reading in congenitally blind individuals peaked in the VWFA, with striking anatomical consistency within and between blind and sighted. The VWFA was reading-selective when contrasted to high-level language and low-level sensory controls. Further preliminary results show that the VWFA is selectively activated also when people learn to read in a new language or using a different modality. Thus, the VWFA is a mutlisensory area specialized for reading regardless of visual experience.

  13. Left Brain vs. Right Brain: Findings on Visual Spatial Capacities and the Functional Neurology of Giftedness (United States)

    Kalbfleisch, M. Layne; Gillmarten, Charles


    As neuroimaging technologies increase their sensitivity to assess the function of the human brain and results from these studies draw the attention of educators, it becomes paramount to identify misconceptions about what these data illustrate and how these findings might be applied to educational contexts. Some of these "neuromyths" have…

  14. Visualizer cognitive style enhances visual creativity. (United States)

    Palmiero, Massimiliano; Nori, Raffaella; Piccardi, Laura


    In the last two decades, interest towards creativity has increased significantly since it was recognized as a skill and as a cognitive reserve and is now always more frequently used in ageing training. Here, the relationships between visual creativity and Visualization-Verbalization cognitive style were investigated. Fifty college students were administered the Creative Synthesis Task aimed at measuring the ability to construct creative objects and the Visualization-Verbalization Questionnaire (VVQ) aimed at measuring the attitude to preferentially use either imagery or verbal strategy while processing information. Analyses showed that only the originality score of inventions was positively predicted by the VVQ score: higher VVQ score (indicating the preference to use imagery) predicted originality of inventions. These results showed that the visualization strategy is involved especially in the originality dimension of creative objects production. In light of neuroimaging results, the possibility that different strategies, such those that involve motor processes, affect visual creativity is also discussed. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  15. Science in the Making: Right Hand, Left Hand. III: Estimating historical rates of left-handedness. (United States)

    McManus, I C; Moore, James; Freegard, Matthew; Rawles, Richard


    The BBC television programme Right Hand, Left Hand, broadcast in August 1953, used a postal questionnaire to ask viewers about their handedness. Respondents were born between 1864 and 1948, and in principle therefore the study provides information on rates of left-handedness in those born in the nineteenth century, a group for which few data are otherwise available. A total of 6,549 responses were received, with an overall rate of left-handedness of 15.2%, which is substantially above that expected for a cohort born in the nineteenth and early twentieth centuries. Left-handers are likely to respond preferentially to surveys about handedness, and the extent of over-response can be estimated in modern control data obtained from a handedness website, from the 1953 BBC data, and from Crichton-Browne's 1907 survey, in which there was also a response bias. Response bias appears to have been growing, being relatively greater in the most modern studies. In the 1953 data there is also evidence that left-handers were more common among later rather than early responders, suggesting that left-handers may have been specifically recruited into the study, perhaps by other left-handers who had responded earlier. In the present study the estimated rate of bias was used to correct the nineteenth-century BBC data, which was then combined with other available data as a mixture of two constrained Weibull functions, to obtain an overall estimate of handedness rates in the nineteenth century. The best estimates are that left-handedness was at its nadir of about 3% for those born between about 1880 and 1900. Extrapolating backwards, the rate of left-handedness in the eighteenth century was probably about 10%, with the decline beginning in about 1780, and reaching around 7% in about 1830, although inevitably there are many uncertainties in those estimates. What does seem indisputable is that rates of left-handedness fell during most of the nineteenth century, only subsequently to rise in

  16. Clinical psychomotor skills among left and right handed medical students: are the left-handed medical students left out? (United States)

    Alnassar, Sami; Alrashoudi, Aljoharah Nasser; Alaqeel, Mody; Alotaibi, Hala; Alkahel, Alanoud; Hajjar, Waseem; Al-Shaikh, Ghadeer; Alsaif, Abdulaziz; Haque, Shafiul; Meo, Sultan Ayoub


    There is a growing perception that the left handed (LH) medical students are facing difficulties while performing the clinical tasks that involve psychomotor skill, although the evidence is very limited and diverse. The present study aimed to evaluate the clinical psychomotor skills among Right-handed (RH) and left-handed (LH) medical students. For this study, 54 (27 left handed and 27 right handed) first year medical students were selected. They were trained for different clinical psychomotor skills including suturing, laparoscopy, intravenous cannulation and urinary catheterization under the supervision of certified instructors. All students were evaluated for psychomotor skills by different instructors. The comparative performance of the students was measured by using a global rating scale, each selected criteria was allotted 5-points score with the total score of 25. There were no significant differences in the performance of psychomotor skills among LH and RH medical students. The global rating score obtained by medical students in suturing techniques was: LH 15.89 ± 2.88, RH 16.15 ± 2.75 (p = 0.737), cannulation techniques LH 20.44 ± 2.81, RH 20.70 ± 2.56 (p = 0.725), urinary catheterization LH 4.33 ± 0.96 RH 4.11 ± 1.05 (p = 0.421). For laparoscopic skills total peg transfer time was shorter among LH medical students compared to RH medical students (LH 129.85 ± 80.87 s vs RH 135.52 ± 104.81 s) (p = 0.825). However, both RH and LH students completed their procedure within the stipulated time. Among LH and RH medical students no significant difference was observed in performing the common surgical psychomotor skills. Surgical skills for LH or RH might not be a result of innate dexterity but rather the academic environment in which they are trained and assessed. Early laterality-related mentoring in medical schools as well as during the clinical residency might reduce the inconveniences faced by the left

  17. [Migraine with visual aura]. (United States)

    Bidot, S; Biotti, D


    Migraine with visual aura is marked by recurrent episodes of transient visual disturbance, often followed by headaches. Its pathophysiology has not been fully understood, but visual auras might be related to a self-propagating wave of cortical depolarization called "cortical spreading depression", triggering a trigemino-vascular "storm" ultimately leading to headaches. The most specific visual symptom is the "fortification spectrum" consisting of glimmering jagged lines spreading from the center to the periphery, and leaving a transient scotoma in its wake. Other visual symptoms are numerous, ranging from elementary positive or negative visual phenomena to complex and elaborate hallucinations. The diagnosis can be made according to the International Classification of Headache Disorders revised in 2013. The main goal of the treatment is to relieve the patient's pain quickly and to decrease the frequency of the episodes. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  18. Attention and visual memory in visualization and computer graphics. (United States)

    Healey, Christopher G; Enns, James T


    A fundamental goal of visualization is to produce images of data that support visual analysis, exploration, and discovery of novel insights. An important consideration during visualization design is the role of human visual perception. How we "see" details in an image can directly impact a viewer's efficiency and effectiveness. This paper surveys research on attention and visual perception, with a specific focus on results that have direct relevance to visualization and visual analytics. We discuss theories of low-level visual perception, then show how these findings form a foundation for more recent work on visual memory and visual attention. We conclude with a brief overview of how knowledge of visual attention and visual memory is being applied in visualization and graphics. We also discuss how challenges in visualization are motivating research in psychophysics.

  19. Visualization: Teaching the Art (United States)


    Visualization : Teaching the Art A Monograph by Major Phillip M. Johnson United States Army School of Advanced Military Studies United States Army...DSN 585-3171 SCHOOL OF ADVANCED MILITARY STUDIES MONOGRAPH APPROVAL Major Phillip M. Johnson Title of Monograph: Visualization : Teaching the Art ...ABSTRACT VISUALIZATION : TEACHING THE ART by MAJOR Phillip M. Johnson, USA, 53 pages. Effectively applying operational art and battle command is a

  20. Cerebral lateralization for the processing of spatial coordinates and categories in left-and right-handers. (United States)



    Subjects judged whether a tachistoscopially lateralized drawing was identical or different to a drawing seen immediately before in free vision. The drawings depicted natural objects (e.g. animals). On half of the trials the tachistoscopic drawing presented the same objects but either the categorical or the coordinate spatial relations (according to Kosslyn's definitions [23]) between the objects were transformed. In the first experiment 38 right-handed subjects (half males and half females) were tested. Categorical judgements were faster when the match drawing appeared in the right visual field, whereas coordinate judgements were faster when the match drawing appeared in the left visual field. In the second experiment 26 right-handed and 40 left-handed subjects participated. Almost all the subjects were female. Right-handed subjects replicated the findings of the subjects in the first experiment. However, the LHs did not show any difference in response times between spatial conditions and visual fields. These findings support Kosslyn's hypothesis that the left and right hemispheres are specialized respectively for processing categorical and coordinate spatial relations. Moreover, they also suggest that this lateralization pattern is not typical of left-handers.

  1. Visual computing scientific visualization and imaging systems

    CERN Document Server


    This volume aims to stimulate discussions on research involving the use of data and digital images as an understanding approach for analysis and visualization of phenomena and experiments. The emphasis is put not only on graphically representing data as a way of increasing its visual analysis, but also on the imaging systems which contribute greatly to the comprehension of real cases. Scientific Visualization and Imaging Systems encompass multidisciplinary areas, with applications in many knowledge fields such as Engineering, Medicine, Material Science, Physics, Geology, Geographic Information Systems, among others. This book is a selection of 13 revised and extended research papers presented in the International Conference on Advanced Computational Engineering and Experimenting -ACE-X conferences 2010 (Paris), 2011 (Algarve), 2012 (Istanbul) and 2013 (Madrid). The examples were particularly chosen from materials research, medical applications, general concepts applied in simulations and image analysis and ot...

  2. The New Left in the European Democracies: The Case of the German Radical Left

    Directory of Open Access Journals (Sweden)

    Marco Damiani


    Full Text Available The new form of the social and political conflict cannot be explained by the traditional categories of right and left, but it articulates to them on two plans, that of the establishment, intended like plan of the structured political conflict from the traditional actors, and that of the anti-establishment, in which new representations of politics emerge. The New Left is characterized by type of intermittent participation and new perspectives on mobilization inside the parties and the social movements. This type of parties differs moreover from the traditional ones left of the socialist and social democratic left in not arranging of organizations collaterals placed under the direction of the leadership of the same party. The mobilization that spontaneously assumes not conventional forms of active participation of the citizens, or is primed by the action of an associative network of which the same parties take part, than however does not monopo-lize the collective action. In this regard, the attention will be dedicated to the study of Die Linke: an anti-establishment party of the non-socialist German left-wing, heir to the communist tradition. The choice was affected to the German model because: 1 Germany is a country with a strong social democratic tradition, but 25 years after the fall of the Berlin Wall the German political system identifies a new antagonist political party; 2 Die Linke represents an interesting case in the political landscape of the European radical left because is a one-party that gives up at the federation of parties to try to unify the political parties of German radical left-wing.

  3. The fastest saccadic responses escape visual masking

    DEFF Research Database (Denmark)

    Crouzet, Sébastien M.; Overgaard, Morten; Busch, Niko A.


    visual processing while the initial feedforward processing is thought to be left intact. We tested a prediction derived from this hypothesis: the fastest responses, being triggered before the beginning of reentrant processing, should escape the OSM interference. In a saccadic choice reaction time task......, which gives access to very early stages of visual processing, target visibility was reduced either by OSM, conventional backward masking, or low stimulus contrast. A general reduction of performance was observed in all three conditions. However, the fastest saccades did not show any sign of interference...... under either OSM or backward masking, as they did under the low-contrast condition. This finding supports the hypothesis that masking interferes mostly with reentrant processing at later stages, while leaving early feedforward processing largely intact....

  4. Visualization in modern cartography

    CERN Document Server

    MacEachren, AM


    Visualization in Modern Cartography explores links between the centuries-old discipline of cartography and today's revolutionary developments in scientific visualization. The book has three main goals: (1) to pass on design and symbolization expertise to the scientific visualization community - information that comes from centuries of pre-computer visualization by cartographers, and their more recent experiences with computerizing the discipline; (2) to help cartographers cope with the dramatic shift from print cartography to a dynamic virtual cartography for which their role is changing from

  5. Visual languages and applications

    CERN Document Server

    Zhang, Kang


    Visual languages have long been a pursuit of effective communication between human and machine. With rapid advances of the Internet and Web technology, human-human communication through the Web or electronic mobile devices is becoming more and more prevalent. Visual Languages and Applications is a comprehensive introduction to diagrammatical visual languages. This book discusses what visual programming languages are, and how such languages and their underlying foundations can be usefully applied to other fields in computer science. It also covers a broad range of contents from the underlying t

  6. A systematic review of left unilateral electroconvulsive therapy. (United States)

    Kellner, C H; Farber, K G; Chen, X R; Mehrotra, A; Zipursky, G D N


    To systematically review the published clinical trials, case series, and case reports on left unilateral (LUL) electrode placement for clinical electroconvulsive therapy (ECT). PubMed, Ovid Medline, and the Cochrane Library were searched for articles concerning LUL ECT. Number of patients, efficacy, and cognitive outcomes were extracted from the papers that met our inclusion criteria. A total of 52 articles were included in this review, consisting of 33 clinical trials, seven case series, and 12 case reports. Overall, the efficacy of LUL electrode placement for the treatment of depression and psychosis is similar to that of right unilateral (RUL) and bilateral (BL) electrode placements. Patients receiving LUL ECT tend to experience more verbal memory impairment than patients receiving RUL ECT, but less verbal impairment than patients receiving BL ECT. In contrast, patients receiving LUL ECT tended to experience the least visual and nonverbal memory impairment, compared to patients receiving RUL or BL ECT. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  7. Stress improves selective attention towards emotionally neutral left ear stimuli. (United States)

    Hoskin, Robert; Hunter, M D; Woodruff, P W R


    Research concerning the impact of psychological stress on visual selective attention has produced mixed results. The current paper describes two experiments which utilise a novel auditory oddball paradigm to test the impact of psychological stress on auditory selective attention. Participants had to report the location of emotionally-neutral auditory stimuli, while ignoring task-irrelevant changes in their content. The results of the first experiment, in which speech stimuli were presented, suggested that stress improves the ability to selectively attend to left, but not right ear stimuli. When this experiment was repeated using tonal stimuli the same result was evident, but only for female participants. Females were also found to experience greater levels of distraction in general across the two experiments. These findings support the goal-shielding theory which suggests that stress improves selective attention by reducing the attentional resources available to process task-irrelevant information. The study also demonstrates, for the first time, that this goal-shielding effect extends to auditory perception. Copyright © 2014 Elsevier B.V. All rights reserved.

  8. Early treatment of dengue foveolitis resulting in good visual outcome

    Directory of Open Access Journals (Sweden)

    Teik June Ling


    Full Text Available A 34-year-old lady presented with sudden onset of central blurring of vision of left eye on Day 7 of dengue fever confirmed by positive IgM serology. Visual acuity was 6/6 OD (right eye and 6/18 OS (left eye. Relative afferent pupillary defect was absent. Anterior segment was unremarkable bilaterally. Fundus examination revealed an area of preretinal haemorrhage with surrounding cotton wool spot and exudation at the macula OS and a single dot hemorrhage at the superotemporal arcade OD. Optical coherence tomography showed bilateral macular oedema with extensive central foveal involvement of intraretinal and subretinal fluid OS. The central macular thickness was 408 µm. Fluorescein angiography showed late leakage at the macula with no capillary fall out OS. No obvious leak was seen OD. She was immediately treated with oral prednisolone 1 mg/kg/day with weekly tapering dose. Subsequently, her left eye showed remarkable improvement in visual acuity to 6/9 and reduction in central macular thickness to 207 µm. In conclusion, dengue foveolitis, although rare, can lead to visionthreatening complication if left untreated. Prompt diagnosis and treatment may result in promising visual outcome, as this case.

  9. Left atrio-vertebral ratio: A new computed-tomography measurement to identify left atrial dilation. (United States)

    Baque-Juston, Marie; Volondat, Manuelle; Fontas, Eric; Roger, Coralie; Brunner, Philippe; Padovani, Bernard; Chevallier, Patrick


    Left cardiac chambers dilation, interstitial lung changes and pleural effusions are the characteristics of cardiogenic pulmonary oedema on computed tomography (CT) of the chest but mensuration of the left atrial size is not routinely performed. Cardiac chambers normal dimensions are known to be proportional to the patient's build and anthropomorphic data but adjustment of chambers dimensions to available elements seen on the axial CT images has never been evaluated before. Our objective was to use data easily available on axial images to directly scale the left atrium. We chose to divide the left atrial diameter by the thoracic vertebral diameter, using the latter as a body-mass indicator. As a preliminary study, we aimed to evaluate the range of values of this left atrio-vertebral ratio (LAVR) by comparing patients suffering from cardiogenic pulmonary oedema with patients free of cardiac disease. We hypothesized that if the difference of values in these two populations of patients was significant enough, this ratio would be relevant and could be used as a quick criterion in different clinical situations. Two radiologists reviewed CT scans of 32 of patients free of cardiac disease and 40 patients in acute cardiac failure. The maximum diameter of the left atrium at the level of the right inferior pulmonary vein was divided by the vertebral transverse diameter to generate a left atrio-vertebral ratio. Receiver operating characteristic curves identified the threshold associated with pulmonary oedema. The mean LAVR was 1.85 ± 0.27 in asymptomatic patients and 2.48 ± 0.35 in patients with pulmonary oedema. A LAVR of 2.1 yielded 85% sensitivity and 88% specificity for the diagnosis of cardiogenic pulmonary oedema. LAVR is a simple new measure directly scaling the left atrial diameter to the anthropomorphic characteristics of the patient. In our series, a ratio above 2.1 is strongly associated with cardiogenic pulmonary oedema indirectly suggesting left atrial dilation

  10. Three dimensional endo-cardiovascular volume-rendered cine computed tomography of isolated left ventricular apical hypoplasia; A case report and literature review

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Sun Hwa; Kim, Yang Min; Lee, Hyun Jong [Sejong General Hospital, Bucheon (Korea, Republic of)


    We report multidetector computed tomography (MDCT) and cardiac magnetic resonance (CMR) findings of a 34-year-old female with isolated left ventricular apical hypoplasia. The MDCT and CMR scans displayed a spherical left ventricle (LV) with extensive fatty infiltration within the myocardium at the apex, interventricular septum and inferior wall, anteroapical origin of the papillary muscle, right ventricle wrapping around the deficient LV apex, and impaired systolic function. MDCT visualized morphologic and also functional findings of this unique cardiomyopathy.

  11. Left ventricular heart failure and pulmonary hypertension† (United States)

    Rosenkranz, Stephan; Gibbs, J. Simon R.; Wachter, Rolf; De Marco, Teresa; Vonk-Noordegraaf, Anton; Vachiéry, Jean-Luc


    Abstract In patients with left ventricular heart failure (HF), the development of pulmonary hypertension (PH) and right ventricular (RV) dysfunction are frequent and have important impact on disease progression, morbidity, and mortality, and therefore warrant clinical attention. Pulmonary hypertension related to left heart disease (LHD) by far represents the most common form of PH, accounting for 65–80% of cases. The proper distinction between pulmonary arterial hypertension and PH-LHD may be challenging, yet it has direct therapeutic consequences. Despite recent advances in the pathophysiological understanding and clinical assessment, and adjustments in the haemodynamic definitions and classification of PH-LHD, the haemodynamic interrelations in combined post- and pre-capillary PH are complex, definitions and prognostic significance of haemodynamic variables characterizing the degree of pre-capillary PH in LHD remain suboptimal, and there are currently no evidence-based recommendations for the management of PH-LHD. Here, we highlight the prevalence and significance of PH and RV dysfunction in patients with both HF with reduced ejection fraction (HFrEF) and HF with preserved ejection fraction (HFpEF), and provide insights into the complex pathophysiology of cardiopulmonary interaction in LHD, which may lead to the evolution from a ‘left ventricular phenotype’ to a ‘right ventricular phenotype’ across the natural history of HF. Furthermore, we propose to better define the individual phenotype of PH by integrating the clinical context, non-invasive assessment, and invasive haemodynamic variables in a structured diagnostic work-up. Finally, we challenge current definitions and diagnostic short falls, and discuss gaps in evidence, therapeutic options and the necessity for future developments in this context. PMID:26508169

  12. Left ventricular noncompaction in a patient presenting with a left ventricular failure

    Directory of Open Access Journals (Sweden)

    Ristić-Anđelkov Anđelka


    Full Text Available Introduction. Left ventricular noncompaction (LVNC is a congenital disorder characterised by prominent trabeculations in the left ventricular myocardium. This heart condition very often goes completely undetected, or is mistaken for hypertrophic cardiomyopathy or coronary disease. Case report. A middle-aged female with a positive family history of coronary disease was admitted with chest pain, electrocardiography (ECG changes in the area of the inferolateral wall and elevation in cardiac specific enzymes. Initially, she was suspected of having acute coronary syndrome. However, in the left ventricular apex, especially alongside the lateral and inferior walls, cardiac ultrasound visualised hypertrabeculation with multiple trabeculae projecting inside the left ventricular cavity. A short-axis view of the heart above the papillary muscles revealed the presence of two layers of the myocardium: a compacted homogeneous layer adjacent to the epicardium and a spongy layer with trabeculae and sinusoids under the endocardium. The thickness ratio between the two layers was 2.2:1. The same abnormalities were corroborated by multislice computed tomography (MSCT of the heart. Conclusion. Left ventricular noncompaction is a rare, usually hereditary cardiomyopathy, which should be considered as a possibility in patients with myocardial hypertrophy. It is very often mistaken for coronary disease owing to ECG changes and elevated cardiac specific enzymes associated with myocardial hypertrophy and heart failure.

  13. Doubling left syntactic positions in Danish

    DEFF Research Database (Denmark)

    Jørgensen, Henrik


    This paper deals with the doubling of left syntactic positions in Danish. Such doublings consist of a referential element: a NP or a clause, and an anaphoric element, an unstressed personal pronoun or an unstressed resumptive adverb. In main clauses, the CP-spec position may double in this way, w...... in the analysis of a broadcasted public speech (sect. 5). In earlier versions of Danish, as shown in sect. 4, the construction is both more frequent in writing and also seems almost obligatory....

  14. Mycobacterium chimaera left ventricular assist device infections. (United States)

    Balsam, Leora B; Louie, Eddie; Hill, Fred; Levine, Jamie; Phillips, Michael S


    A global outbreak of invasive Mycobacterium chimaera infections after cardiac surgery has recently been linked to bioaerosols from contaminated heater-cooler units. The majority of cases have occurred after valvular surgery or aortic graft surgery and nearly half have resulted in death. To date, infections in patients with left ventricular assist devices (LVADs) have not been characterized in the literature. We report two cases of device-associated M. chimaera infection in patients with continuous-flow LVADs and describe challenges related to diagnosis and management in this population. © 2017 Wiley Periodicals, Inc.

  15. Anomalous Origin of Left Circumflex Artery


    ?itaku, Hajdin; Kamberi, Lulzim; Gorani, Daut; Ko?inaj, Dardan; Krasniqi, Xhevdet


    Introduction: The coronary anatomic variation of the left circumflex artery (LCx) is considered as the most common anatomic variation with a separate ostium from the right sinus, and very unusual variation as a proximal branch of right coronary artery (RCA). Case report: We report two cases, the first case is a 64-year-old man with chest pain and with history of hypertension, obesity, dyslipidemia and current smoker, and the second case is a 67-year-old who presented to the emergency departme...

  16. Evaluation of left ventricular diastolic function by appreciating the shape of time activity curve

    International Nuclear Information System (INIS)

    Nishimura, Tohru; Taya, Makoto; Shimoyama, Katsuya; Sasaki, Akira; Mizuno, Haruyoshi; Tahara, Yorio; Ono, Akifumi; Ishikawa, Kyozo


    To determine left ventricular diastolic function (LVDF), the shape of time activity curve and primary differential curve, as acquired by Tc-99m radionuclide angiography, were visually assessed. The study popoulation consisted of 1647 patients with heart disease, such as hypertension, ischemic heart disease, cardiomyopathy and valvular disease. Fifty-six other patients were served as controls. The LVDF was divided into 4 degrees: 0=normal, I=slight disturbance, II=moderate disturbance, and III=severe disturbance. LVDF variables, including time to peak filling (TPF), TPF/time to end-systole, peak filling rate (PFR), PFR/t, 1/3 filling fraction (1/3 FR), and 1/3 FR/t, were calculated from time activity curve. There was no definitive correlation between each variable and age or heart rate. Regarding these LVDF variables, except for 1/3 FR, there was no significant difference between the group 0 of heart disease patients and the control group. Among the groups 0-III of heart disease patients, there were significant difference in LVDF variables. Visual assessement concurred with left ventricular ejection fraction, PFR/end-diastolic curve, and filling rate/end-diastolic curve. Visual assessment using time activity curve was considered useful in the semiquantitative determination of early diastolic function. (N.K.)

  17. Sound-contingent visual motion aftereffect

    Directory of Open Access Journals (Sweden)

    Kobayashi Maori


    Full Text Available Abstract Background After a prolonged exposure to a paired presentation of different types of signals (e.g., color and motion, one of the signals (color becomes a driver for the other signal (motion. This phenomenon, which is known as contingent motion aftereffect, indicates that the brain can establish new neural representations even in the adult's brain. However, contingent motion aftereffect has been reported only in visual or auditory domain. Here, we demonstrate that a visual motion aftereffect can be contingent on a specific sound. Results Dynamic random dots moving in an alternating right or left direction were presented to the participants. Each direction of motion was accompanied by an auditory tone of a unique and specific frequency. After a 3-minutes exposure, the tones began to exert marked influence on the visual motion perception, and the percentage of dots required to trigger motion perception systematically changed depending on the tones. Furthermore, this effect lasted for at least 2 days. Conclusions These results indicate that a new neural representation can be rapidly established between auditory and visual modalities.

  18. Prognosis and Treatment of Visual Field Defects. (United States)

    Agarwal, Aniruddha; Kedar, Sachin


    Visual field deficits are common in neurologic disease conditions such as cerebrovascular disease, traumatic brain injury, and brain tumors. Loss of visual fields may lead to impairment of reading skills (hemianopic dyslexia) and limitations of daily activities such as driving, which can have a significant impact on an individual's socioeconomic status and quality of life. Moreover, patients with motor deficits from neurologic diseases have a 20% decreased likelihood of achieving independence in ambulation and self-care activities with coexisting hemianopia. Studies on the natural history of homonymous hemianopia have shown that spontaneous improvement of visual fields may occur in less than 40% of individuals early in the disease process. Improvement is usually incomplete, which implies that a significant number of individuals will be left with a disabling visual deficit. Although several methods of rehabilitation (optical, compensatory, and restitution therapy) are used in practice, none, unfortunately, have shown consistent and significant benefits. In this review, the authors focus on the natural history, impact, prognosis, and treatment modalities for neurologic field defects. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

  19. The association of visual memory with hippocampal volume.

    Directory of Open Access Journals (Sweden)

    Andrea R Zammit

    Full Text Available In this study we investigated the role of hippocampal volume (HV in visual memory.Participants were a subsample of older adults (> = 70 years from the Einstein Aging Study. Visual performance was measured using the Complex Figure (CF copy and delayed recall tasks from the Repeatable Battery for the Assessment of Neuropsychological Status. Linear regressions were fitted to study associations between HV and visual tasks.Participants' (n = 113, mean age = 78.9 years average scores on the CF copy and delayed recall were 17.4 and 11.6, respectively. CF delayed recall was associated with total (β = .031, p = 0.001 and left (β = 0.031, p = 0.001 and right HVs (β = 0.24, p = 0.012. CF delayed recall remained significantly associated with left HV even after we also included right HV (β = 0.27, p = 0.025 and the CF copy task (β = 0.30, p = 0.009 in the model. CF copy did not show any significant associations with HV.Our results suggest that left HV contributes in retrieval of visual memory in older adults.

  20. Exploring Visual Bookmarks and Layered Visualizations

    NARCIS (Netherlands)

    J.T. Teuben (Jan)


    textabstractCultural heritage experts are confronted with a difficult information gathering task while conducting comparison searches. Saving searches and re-examining previous work could help them to do their work. In this paper we propose a solution in which we combine visual bookmarks for saving

  1. Personal Visualization and Personal Visual Analytics. (United States)

    Huang, Dandan; Tory, Melanie; Aseniero, Bon Adriel; Bartram, Lyn; Bateman, Scott; Carpendale, Sheelagh; Tang, Anthony; Woodbury, Robert


    Data surrounds each and every one of us in our daily lives, ranging from exercise logs, to archives of our interactions with others on social media, to online resources pertaining to our hobbies. There is enormous potential for us to use these data to understand ourselves better and make positive changes in our lives. Visualization (Vis) and visual analytics (VA) offer substantial opportunities to help individuals gain insights about themselves, their communities and their interests; however, designing tools to support data analysis in non-professional life brings a unique set of research and design challenges. We investigate the requirements and research directions required to take full advantage of Vis and VA in a personal context. We develop a taxonomy of design dimensions to provide a coherent vocabulary for discussing personal visualization and personal visual analytics. By identifying and exploring clusters in the design space, we discuss challenges and share perspectives on future research. This work brings together research that was previously scattered across disciplines. Our goal is to call research attention to this space and engage researchers to explore the enabling techniques and technology that will support people to better understand data relevant to their personal lives, interests, and needs.

  2. Multiple Coronary Artery Microfistulas Associated with Apical Hypertrophic Cardiomyopathy: Left and Right Coronary Artery to the Left Ventricle

    Directory of Open Access Journals (Sweden)

    Jeong-Woo Choi


    Full Text Available A 76-year-old woman underwent coronary angiography for chest pain. On the coronary angiogram, no significant coronary artery atherosclerotic stenosis was observed. Multiple coronary artery microfistulas, draining from the left anterior descending artery to the left ventricle and from the posterior descending artery of the right coronary artery to the left ventricle, were observed. Apical wall thickening and fistula flow from the left anterior descending artery were demonstrated by using transthoracic echocardiography. We describe a rare case of multiple coronary artery microfistulas from the left and right coronary artery to the left ventricle combined with apical hypertrophic cardiomyopathy.

  3. Heart Failure with Transient Left Bundle Branch Block in the Setting of Left Coronary Fistula

    Directory of Open Access Journals (Sweden)

    Stephen P. Juraschek


    Full Text Available Coronary arterial fistulas are rare communications between vessels or chambers of the heart. Although cardiac symptoms associated with fistulas are well described, fistulas are seldom considered in the differential diagnosis of acute myocardial ischemia. We describe the case of a 64-year-old man who presented with left shoulder pain, signs of heart failure, and a new left bundle branch block (LBBB. Cardiac catheterization revealed a small left anterior descending (LAD-to-pulmonary artery (PA fistula. Diuresis led to subjective improvement of the patient's symptoms and within several days the LBBB resolved. We hypothesize that the coronary fistula in this patient contributed to transient ischemia of the LAD territory through a coronary steal mechanism. We elected to observe rather than repair the fistula, as his symptoms and ECG changes resolved with treatment of his heart failure.

  4. When right feels left: referral of touch and ownership between the hands.

    Directory of Open Access Journals (Sweden)

    Valeria I Petkova

    Full Text Available Feeling touch on a body part is paradigmatically considered to require stimulation of tactile afferents from the body part in question, at least in healthy non-synaesthetic individuals. In contrast to this view, we report a perceptual illusion where people experience "phantom touches" on a right rubber hand when they see it brushed simultaneously with brushes applied to their left hand. Such illusory duplication and transfer of touch from the left to the right hand was only elicited when a homologous (i.e., left and right pair of hands was brushed in synchrony for an extended period of time. This stimulation caused the majority of our participants to perceive the right rubber hand as their own and to sense two distinct touches--one located on the right rubber hand and the other on their left (stimulated hand. This effect was supported by quantitative subjective reports in the form of questionnaires, behavioral data from a task in which participants pointed to the felt location of their right hand, and physiological evidence obtained by skin conductance responses when threatening the model hand. Our findings suggest that visual information augments subthreshold somatosensory responses in the ipsilateral hemisphere, thus producing a tactile experience from the non-stimulated body part. This finding is important because it reveals a new bilateral multisensory mechanism for tactile perception and limb ownership.

  5. Visual Factors in Reading (United States)

    Singleton, Chris; Henderson, Lisa-Marie


    This article reviews current knowledge about how the visual system recognizes letters and words, and the impact on reading when parts of the visual system malfunction. The physiology of eye and brain places important constraints on how we process text, and the efficient organization of the neurocognitive systems involved is not inherent but…

  6. Visual Complexity: A Review (United States)

    Donderi, Don C.


    The idea of visual complexity, the history of its measurement, and its implications for behavior are reviewed, starting with structuralism and Gestalt psychology at the beginning of the 20th century and ending with visual complexity theory, perceptual learning theory, and neural circuit theory at the beginning of the 21st. Evidence is drawn from…

  7. The Visual System

    Medline Plus

    Full Text Available ... with respect to blinding eye diseases, visual disorders, mechanisms of visual function, preservation of sight, and the ... Contact Us A-Z Site Map NEI on Social Media Information in Spanish (Información en español) Website, ...

  8. English 3135: Visual Rhetoric (United States)

    Gatta, Oriana


    As an advanced rhetoric and composition doctoral student, I taught Engl 3135: Visual Rhetoric, a three-credit upper-level course offered by the Department of English at Georgia State University. Mary E. Hocks originally designed this course in 2000 to, in her words, "introduce visual information design theories and practices for writers [and]…

  9. Critical Reading: Visual Skills. (United States)

    Adams, Dennis M.

    The computer controlled visual media, particularly television, are becoming an increasingly powerful instrument for the manipulation of thought. Powerful visual images increasingly reflect and shape personal and external reality--politics being one such example--and it is crucial that the viewing public understand the nature of these media…

  10. Mathematica data visualization

    CERN Document Server

    Saquib, Nazmus


    If you are planning to create data analysis and visualization tools in the context of science, engineering, economics, or social science, then this book is for you. With this book, you will become a visualization expert, in a short time, using Mathematica.

  11. Visual Word Ambiguity

    NARCIS (Netherlands)

    van Gemert, J.C.; Veenman, C.J.; Smeulders, A.W.M.; Geusebroek, J.M.


    This paper studies automatic image classification by modeling soft assignment in the popular codebook model. The codebook model describes an image as a bag of discrete visual words selected from a vocabulary, where the frequency distributions of visual words in an image allow classification. One

  12. Complicating Visual Culture (United States)

    Daiello, Vicki; Hathaway, Kevin; Rhoades, Mindi; Walker, Sydney


    Arguing for complicating the study of visual culture, as advocated by James Elkins, this article explicates and explores Lacanian psychoanalytic theory and pedagogy in view of its implications for art education practice. Subjectivity, a concept of import for addressing student identity and the visual, steers the discussion informed by pedagogical…

  13. Visual experience and blindsight

    DEFF Research Database (Denmark)

    Overgaard, Morten


    Blindsight is classically defined as residual visual capacity, e.g., to detect and identify visual stimuli, in the total absence of perceptual awareness following lesions to V1. However, whereas most experiments have investigated what blindsight patients can and cannot do, the literature contains...

  14. The Visual System

    Medline Plus

    Full Text Available ... programs with respect to blinding eye diseases, visual disorders, mechanisms of visual function, preservation of sight, and the special health ... Pressroom Contacts Dustin Hays - Chief, Science Communication Kathryn DeMott, Media Relations ...

  15. Exploring the Visual Landscape

    NARCIS (Netherlands)

    Nijhuis, S.; Van Lammeren, R.; Van der Hoeven, F.


    Exploring the Visual Landscape is about the combination of landscape research and planning, visual perception and Geographic Information Science. It showcases possible ways of getting a grip on themes like: landscape openness, cluttering of the rural landscape, high-rise buildings in relation to

  16. Sizing up visualizations

    DEFF Research Database (Denmark)

    Jakobsen, Mikkel Rønne; Hornbæk, Kasper


    Whereas the literature is clear on the benefits of large displays and visualizations, little is known about their combination, that is, how display size affect the usability of visualizations. We describe a controlled experiment where 19 participants used focus+context, overview+detail, and zoomi...

  17. The visual information system (United States)

    Merlyn J. Paulson


    This paper outlines a project level process (V.I.S.) which utilizes very accurate and flexible computer algorithms in combination with contemporary site analysis and design techniques for visual evaluation, design and management. The process provides logical direction and connecting bridges through problem identification, information collection and verification, visual...

  18. Visualizing Qualitative Information (United States)

    Slone, Debra J.


    The abundance of qualitative data in today's society and the need to easily scrutinize, digest, and share this information calls for effective visualization and analysis tools. Yet, no existing qualitative tools have the analytic power, visual effectiveness, and universality of familiar quantitative instruments like bar charts, scatter-plots, and…

  19. Normalized medical information visualization. (United States)

    Sánchez-de-Madariaga, Ricardo; Muñoz, Adolfo; Somolinos, Roberto; Castro, Antonio; Velázquez, Iker; Moreno, Oscar; García-Pacheco, José L; Pascual, Mario; Salvador, Carlos H


    A new mark-up programming language is introduced in order to facilitate and improve the visualization of ISO/EN 13606 dual model-based normalized medical information. This is the first time that visualization of normalized medical information is addressed and the programming language is intended to be used by medical non-IT professionals.

  20. Network Visualization Project (NVP) (United States)


    Visualization Project (NVP) by Terry Wen American Society of Engineering Education, Washington, DC Lisa M Marvel Computational and Information Sciences...front-end presentation and construction of the application itself. 15. SUBJECT TERMS computer network traffic, computer network security, computer visualization, network traffic analysis, network forensics 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT UU 18. NUMBER OF

  1. Music Alters Visual Perception

    NARCIS (Netherlands)

    Jolij, Jacob; Meurs, Maaike


    Background: Visual perception is not a passive process: in order to efficiently process visual input, the brain actively uses previous knowledge (e. g., memory) and expectations about what the world should look like. However, perception is not only influenced by previous knowledge. Especially the

  2. Visual thinking and neuroscience. (United States)

    Smith, C U M


    After a consideration of visual thinking in science the role of such thinking in neuroscience is discussed. Three instances are examined - cortical column, retina, impulse - and it is argued that visual thinking is employed, though in different ways, in each. It lies at the core of neurobiological thought.

  3. Visualizing the Heliosphere (United States)

    Bridgman, William T.; Shirah, Greg W.; Mitchell, Horace G.


    Today, scientific data and models can combine with modern animation tools to produce compelling visualizations to inform and educate. The Scientific Visualization Studio at Goddard Space Flight Center merges these techniques from the very different worlds of entertainment and science to enable scientists and the general public to 'see the unseeable' in new ways.

  4. Interactive Visualization of Dependencies (United States)

    Moreno, Camilo Arango; Bischof, Walter F.; Hoover, H. James


    We present an interactive tool for browsing course requisites as a case study of dependency visualization. This tool uses multiple interactive visualizations to allow the user to explore the dependencies between courses. A usability study revealed that the proposed browser provides significant advantages over traditional methods, in terms of…

  5. Constructing visual representations

    DEFF Research Database (Denmark)

    Huron, Samuel; Jansen, Yvonne; Carpendale, Sheelagh


    The accessibility of infovis authoring tools to a wide audience has been identified as a major research challenge. A key task in the authoring process is the development of visual mappings. While the infovis community has long been deeply interested in finding effective visual mappings, comparati...

  6. Nonlinear left-handed transmission line metamaterials

    International Nuclear Information System (INIS)

    Kozyrev, A B; Weide, D W van der


    Metamaterials, exhibiting simultaneously negative permittivity ε and permeability μ, more commonly referred to as left-handed metamaterials (LHMs) and also known as negative-index materials, have received substantial attention in the scientific and engineering communities [1]. Most studies of LHMs (and electromagnetic metamaterials in general) have been in the linear regime of wave propagation and have already inspired new types of microwave circuits and devices. The results of these studies have already been the subject of numerous reviews and books. This review covers a less explored but rapidly developing area of investigation involving media that combine nonlinearity (dependence of the permittivity and permeability on the magnitude of the propagating field) with the anomalous dispersion exhibited by LHM. The nonlinear phenomena in such media will be considered on the example of a model system: the nonlinear left-handed transmission line. These nonlinear phenomena include parametric generation and amplification, harmonic and subharmonic generation as well as modulational instabilities and envelope solitons. (topical review)

  7. Left hepatectomy after right paramedian sectoriectomy. (United States)

    Takamoto, Takeshi; Hashimoto, Takuya; Makuuchi, Masatoshi


    Repeat hepatectomy is beneficial for selected patients with recurrence of liver malignancies. However, the operative procedure becomes technically demanding when the previous hepatectomy was complex, with hepatic veins and stump of portal pedicles exposed on the liver transection surface. We performed left hepatectomy after right paramedian sectoriectomy (RPMS) for three patients. Here, we describe our surgical technique and the postoperative outcomes achieved. This procedure allowed for safe adhesiolysis between the middle and right hepatic veins by following a fibrous plane. The mean operative time was 8.7 h, including 4.9 h of adhesiolysis. The mean remnant liver volume (right lateral sector and the caudate lobe) was calculated as 704 ml, being 62% of total liver volume. There was no postoperative liver failure or mortality. In conclusion, left hepatectomy after RPMS is a feasible procedure for patients with sufficient remnant liver volume, even though the middle and right hepatic veins run side by side after liver regeneration.

  8. Reversal of left ventricular hypertrophy by propranolol in ...

    African Journals Online (AJOL)

    Background: Hypertension contributes significantly to the development of left ventricular hypertrophy. Left ventricular hypertrophy is associated with increased incidence of sudden cardiac death. Recognition and management of hypertension is, therefore, imperative. Objective: To establish whether propranolol can reverse ...

  9. Incidental retroaortic left innominate vein in adult patient

    Directory of Open Access Journals (Sweden)

    Alexandre Semionov, MD, PhD


    Full Text Available Retro-aortic left innominate vein is a rare vascular abnormality, usually associated with congenital heart disease. Here we report a case of isolated retro-aortic left innominate vein in an adult female.

  10. Rare occurrence of the left maxillary horizontal third molar impaction ...

    African Journals Online (AJOL)

    Rare occurrence of the left maxillary horizontal third molar impaction, the right maxillary third molar vertical impaction and the left mandibular third molar vertical impaction with inferior alveolar nerve proximity in a 30 year old female: a case report.

  11. Visual Signs of Ageing

    Directory of Open Access Journals (Sweden)

    Helle Rexbye


    Full Text Available Consumer culture has placed the ageing body in a dilemma of representation. Physical appearance has become increasingly important as a symbol of identity, and at the same time society idealizes youth. This study explores visual ageing empirically. By using photographs of older persons (70+ as starting point, it is explored how visual age is assessed and interpreted. It is shown that informants read age in a spread of stages and categories. Main age indicators are biological markers: skin, eyes, and hair colour, but supplemented by vigour, style, and grooming. Furthermore, in-depth interviews indicate that visual age is mainly interpreted into categories and moral regulations rooted in early modernity. Subsequently the question of a postmodern perspective of visual ageing is discussed in this article. The empirical findings in the study question a postmodern fluidity of visual signs – at least when the concern is signs of ageing.

  12. Visualization of JPEG Metadata (United States)

    Malik Mohamad, Kamaruddin; Deris, Mustafa Mat

    There are a lot of information embedded in JPEG image than just graphics. Visualization of its metadata would benefit digital forensic investigator to view embedded data including corrupted image where no graphics can be displayed in order to assist in evidence collection for cases such as child pornography or steganography. There are already available tools such as metadata readers, editors and extraction tools but mostly focusing on visualizing attribute information of JPEG Exif. However, none have been done to visualize metadata by consolidating markers summary, header structure, Huffman table and quantization table in a single program. In this paper, metadata visualization is done by developing a program that able to summarize all existing markers, header structure, Huffman table and quantization table in JPEG. The result shows that visualization of metadata helps viewing the hidden information within JPEG more easily.

  13. Visualization and mathematics III

    CERN Document Server

    Polthier, Konrad


    This research book on Mathematical Visualization contains state of the art presentations on visualization problems in mathematics, on fundamental mathematical research in computer graphics, and on software frameworks for the application of visualization to real-world problems. All contributions were written by leading experts in the field and peer-refereed by an international editorial team. The book grew out of the third international workshop "Visualization and Mathematics", which was held from May 22-25, 2002 in Berlin. The themes of the book cover important recent developments on - Geometry and Combinatorics of Meshes - Discrete Vector Fields and Topology - Geometric Modelling - Image Based Visualization - Software Environments and Applications - Education and Communication The variety of topics makes the book a suitable resource for researchers, lecturers, and practitioners;

  14. Houdini for Astrophysical Visualization (United States)

    Naiman, J. P.; Borkiewicz, Kalina; Christensen, A. J.


    The rapid growth in scale and complexity of both computational and observational astrophysics over the past decade necessitates efficient and intuitive methods for examining and visualizing large data sets. Here, we discuss some newly developed tools used to import and manipulate astrophysical data into the three-dimensional visual effects software, Houdini. This software is widely used by visual effects artists, but a recently implemented Python API now allows astronomers to more easily use Houdini as a visualization tool. This paper includes a description of features, workflow, and various example visualizations. The project website,, is aimed at a scientific audience and contains Houdini tutorials and links to the Python script Bitbucket repository to simplify the process of importing and rendering astrophysical data.

  15. NASA's Scientific Visualization Studio (United States)

    Mitchell, Horace G.


    Since 1988, the Scientific Visualization Studio(SVS) at NASA Goddard Space Flight Center has produced scientific visualizations of NASA s scientific research and remote sensing data for public outreach. These visualizations take the form of images, animations, and end-to-end systems and have been used in many venues: from the network news to science programs such as NOVA, from museum exhibits at the Smithsonian to White House briefings. This presentation will give an overview of the major activities and accomplishments of the SVS, and some of the most interesting projects and systems developed at the SVS will be described. Particular emphasis will be given to the practices and procedures by which the SVS creates visualizations, from the hardware and software used to the structures and collaborations by which products are designed, developed, and delivered to customers. The web-based archival and delivery system for SVS visualizations at will also be described.

  16. Visual text hallucinations of thoughts in an alexic woman. (United States)

    Yamagata, Bun; Kobayashi, Hitomi; Yamamoto, Hideki; Mimura, Masaru


    In this report we describe a patient with a clinical diagnosis of dementia with Lewy bodies, who had hallucinations of reading her thoughts in the air although she was alexic and unable to read. She also had severe visuoperceptual deficits and closing-in phenomenon. SPECT imaging demonstrated hypoperfusion of the left parieto-occipital cortices together with hyperperfusion of the left orbitofronto-temporal areas. Her visual text hallucinations may represent another type of textual hallucinations related to syntacto-semantic network hyperactivation, which is implicated in auditory hallucinations in schizophrenia. Copyright © 2014 Elsevier B.V. All rights reserved.

  17. Anesthetic implications of total anomalous systemic venous connection to left atrium with left isomerism

    Directory of Open Access Journals (Sweden)

    Parimala Prasanna Simha


    Full Text Available Total anomalous systemic venous connection (TASVC to the left atrium (LA is a rare congenital anomaly. An 11-year-old girl presented with complaints of palpitations and cyanosis. TASVC with left isomerism and noncompaction of LV was diagnosed after contrast echocardiogram and computed tomography angiogram. The knowledge of anatomy and pathophysiology is essential for the successful management of these cases. Anesthetic concerns in this case were polycythemia, paradoxical embolism and rhythm abnormalities. The patient was successfully operated by rerouting the systemic venous connection to the right atrium.

  18. Asymmetric top-down modulation of ascending visual pathways in pigeons. (United States)

    Freund, Nadja; Valencia-Alfonso, Carlos E; Kirsch, Janina; Brodmann, Katja; Manns, Martina; Güntürkün, Onur


    Cerebral asymmetries are a ubiquitous phenomenon evident in many species, incl. humans, and they display some similarities in their organization across vertebrates. In many species the left hemisphere is associated with the ability to categorize objects based on abstract or experience-based behaviors. Using the asymmetrically organized visual system of pigeons as an animal model, we show that descending forebrain pathways asymmetrically modulate visually evoked responses of single thalamic units. Activity patterns of neurons within the nucleus rotundus, the largest thalamic visual relay structure in birds, were differently modulated by left and right hemispheric descending systems. Thus, visual information ascending towards the left hemisphere was modulated by forebrain top-down systems at thalamic level, while right thalamic units were strikingly less modulated. This asymmetry of top-down control could promote experience-based processes within the left hemisphere, while biasing the right side towards stimulus-bound response patterns. In a subsequent behavioral task we tested the possible functional impact of this asymmetry. Under monocular conditions, pigeons learned to discriminate color pairs, so that each hemisphere was trained on one specific discrimination. Afterwards the animals were presented with stimuli that put the hemispheres in conflict. Response patterns on the conflicting stimuli revealed a clear dominance of the left hemisphere. Transient inactivation of left hemispheric top-down control reduced this dominance while inactivation of right hemispheric top-down control had no effect on response patterns. Functional asymmetries of descending systems that modify visual ascending pathways seem to play an important role in the superiority of the left hemisphere in experience-based visual tasks. Copyright © 2015. Published by Elsevier Ltd.

  19. Activation of extrastriate and frontal cortical areas by visual words and word-like stimuli

    International Nuclear Information System (INIS)

    Petersen, S.E.; Fox, P.T.; Snyder, A.Z.; Raichle, M.E.


    Visual presentation of words activates extrastriate regions of the occipital lobes of the brain. When analyzed by positron emission tomography (PET), certain areas in the left, medial extrastriate visual cortex were activated by visually presented pseudowords that obey English spelling rules, as well as by actual words. These areas were not activated by nonsense strings of letters or letter-like forms. Thus visual word form computations are based on learned distinctions between words and nonwords. In addition, during passive presentation of words, but not pseudowords, activation occurred in a left frontal area that is related to semantic processing. These findings support distinctions made in cognitive psychology and computational modeling between high-level visual and semantic computations on single words and describe the anatomy that may underlie these distinctions

  20. Visualisation of the left superior intercostal vein in MR

    International Nuclear Information System (INIS)

    Medrea, M.; Meydam, K.; Schmitt, W.


    A retrospective study of 56 MRT chest examinations showed the left intercostal vein in its horizontal trajectory in 3 patients with left mediastinal masses compressing the superior vena cava. In 2 patients the posterior trajectory of the horizontal segment was clearly visualised. In the third case the anterior part, namely the insertion of the left superior intercostal vein into the left brachiocephalic trunk, was demonstrated. (orig.) [de

  1. Visual Grouping in Accordance With Utterance Planning Facilitates Speech Production

    Directory of Open Access Journals (Sweden)

    Liming Zhao


    Full Text Available Research on language production has focused on the process of utterance planning and involved studying the synchronization between visual gaze and the production of sentences that refer to objects in the immediate visual environment. However, it remains unclear how the visual grouping of these objects might influence this process. To shed light on this issue, the present research examined the effects of the visual grouping of objects in a visual display on utterance planning in two experiments. Participants produced utterances of the form “The snail and the necklace are above/below/on the left/right side of the toothbrush” for objects containing these referents (e.g., a snail, a necklace and a toothbrush. These objects were grouped using classic Gestalt principles of color similarity (Experiment 1 and common region (Experiment 2 so that the induced perceptual grouping was congruent or incongruent with the required phrasal organization. The results showed that speech onset latencies were shorter in congruent than incongruent conditions. The findings therefore reveal that the congruency between the visual grouping of referents and the required phrasal organization can influence speech production. Such findings suggest that, when language is produced in a visual context, speakers make use of both visual and linguistic cues to plan utterances.

  2. Branching patterns of left coronary artery among North Indians ...

    African Journals Online (AJOL)

    The left coronary artery displays variations in pattern, number and distribution of its branches. These variations influence the manifestation and extent of the coronary artery disease affecting the left main branch. A total of 100 North Indian cadaveric hearts were dissected to observe the main trunk of the left coronary artery.

  3. Learning Conflict Among Mixed-Dominance Left-Handed Individuals. (United States)

    Blai, Boris, Jr.

    This study investigates the hypothesis that it is mixed-dominance among left handers (i.e. left handedness and right eye and/or foot dominance), that is related to academic learning difficulties among such individuals, rather than the generally held notion that their difficulties stem from the fact that they are left handers in a "right handed…

  4. Spatial Deficit in Familial Left-Handed Children. (United States)

    And Others; Eme, Robert


    The study evaluated the hypothesis that familial left-handed children, who presumably have bilateral representation of language ability, should show an impairment in spatial abiblity on 44 children (22 right handed, 11 familial left handed, and 11 nonfamilial left handed) whose average age was 8 years old. (Author/PHR)

  5. Left-Handed Students: A Forgotten Minority. Fastback 399. (United States)

    Kelly, Evelyn B.

    This fastback, a booklet bound "left-handed," is designed to help educators become aware of the problems faced by left-handed students in school and to suggest ways that many of the problems might be solved. Following an introduction discussing a personal experience with left-handedness, the booklet continues with a brief history of the treatment…

  6. Left-Handed Children--Are They Losing Out? (United States)

    Milsom, Lauren


    Discusses difficulties faced by left-handed children in everyday schoolwork. Highlights include right-handed bias of toys, clothing, and tools; the need for guidance in handwriting; problem areas including domestic science, arts and crafts, and metal and woodwork; left-hand advantages in sports and creative arts; and the European Left-Handers Club…

  7. Prevalence of left ventricular diastolic dysfunction in newly ...

    African Journals Online (AJOL)

    They were divided into hypertensives without left ventricular hypertrophy and those with left ventricular hypertrophy based on echocardiographically determined left ventricular mass index. Pulsed Doppler transmitral inflow and the pulmonary venous flow waves were used to categorise the patterns of diastolic dysfunction.

  8. Left Ventricular Geometry In Nigerians With Type II Diabetes Mellitus ...

    African Journals Online (AJOL)

    Background: Left ventricular hypertrophy is independently associated with increased incidence of cardiovascular disease, cardiovascular and all cause mortality. In a relatively healthy hypertensive adult population, type II diabetes is associated with higher left ventricular mass, concentric left ventricular geometry and lower ...

  9. Isolated left carotid artery in CHARGE association: diagnosis and repair. (United States)

    Ghalili, K; Issenberg, H J; Freeman, N J; Brodman, R F


    Isolation of the left carotid artery is extremely rare. We report a case of isolation of the left carotid artery with CHARGE association. Aortic arch abnormalities should be looked for in all children with CHARGE association. The technique of repair involved implantation of the isolated left carotid artery to the ascending aorta.

  10. Visual Interpretation of Children's Books. (United States)

    Goldstone, Bette P.


    Examines how visual literacy (the ability to interpret the visual images of advertisements, illustrations, television, and other visual media) can promote creative and analytic thinking. Provides several instructional strategies to teach visual literacy through book illustrations. Notes that visual literacy is essential in a world increasingly…

  11. Designing Visual Earth: Multimedia Geographic Visualization for the Classroom. (United States)

    McWilliams, Harold


    Provides information on computer software using Geographic Information Systems (GIS) and visualization technologies and Visual Earth, a series of integrated classroom solutions for a variety of science topics. Describes some uses of GIS and Visual Earth in science classrooms. (ASK)

  12. Left ventricular assist device implantation in patients after left ventricular reconstruction. (United States)

    Palmen, Meindert; Braun, Jerry; Beeres, Saskia L M A; Klautz, Robert J M


    Left ventricular assist device (LVAD) implantation can be challenging in patients with a prior surgical ventricular restoration (SVR). In this case series of heart failure patients with a history of SVR, we describe the surgical technique and outcome of a customized approach for inflow cannula orientation. Seven patients with a history of SVR with end-stage chronic heart failure were accepted for long-term LVAD support. In all patients, the Dacron patch was removed through left ventriculotomy and a Hegar 22 dilator was inserted at the estimated optimal position of the LVAD inflow cannula. The left ventricle was reconstructed around the dilator from the left ventricular (LV) apex to the base. Finally, the LVAD sewing ring was sutured onto the remaining apical defect and a HeartWare® LVAD was implanted. LVAD implantation was successful in all 7 patients. Transoesophageal echocardiography ensured an adequate LVAD position and inflow and outflow cannula Doppler flow recordings. The mean intensive care unit stay was 5.8 ± 2.6 days, and the hospital stay after surgery was 32 ± 16 days. All patients follow regular visits (follow-up 20 ± 16 months) at the outpatient clinic without any remarkable event. Using the technique described, LVAD implantation in patients after SVR is feasible and safe. © The Author 2016. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.

  13. Stomach in Contact with the Bladder: A Sonographic Sign of Left Congenital Diaphragmatic Hernia. (United States)

    Aiello, Horacio; Meller, César; Vázquez, Lucía; Otaño, Lucas


    The evaluation of the characteristics of the fetal stomach should be part of every routine prenatal ultrasound after 11 weeks. A position that has not been previously described in the literature is the stomach in contact with the bladder. We describe 6 cases with the ultrasonographic finding of the stomach in contact with the bladder, all of them in fetuses with left-sided congenital diaphragmatic hernia. Even though the reasons for this striking position of the stomach are not clear, our series highlights the fact that the visualization of the stomach in contact with the bladder may be a specific sonographic marker of congenital diaphragmatic hernia. © 2015 S. Karger AG, Basel.

  14. Exploring the neural correlates of visual creativity (United States)

    Liew, Sook-Lei; Dandekar, Francesco


    Although creativity has been called the most important of all human resources, its neural basis is still unclear. In the current study, we used fMRI to measure neural activity in participants solving a visuospatial creativity problem that involves divergent thinking and has been considered a canonical right hemisphere task. As hypothesized, both the visual creativity task and the control task as compared to rest activated a variety of areas including the posterior parietal cortex bilaterally and motor regions, which are known to be involved in visuospatial rotation of objects. However, directly comparing the two tasks indicated that the creative task more strongly activated left hemisphere regions including the posterior parietal cortex, the premotor cortex, dorsolateral prefrontal cortex (DLPFC) and the medial PFC. These results demonstrate that even in a task that is specialized to the right hemisphere, robust parallel activity in the left hemisphere supports creative processing. Furthermore, the results support the notion that higher motor planning may be a general component of creative improvisation and that such goal-directed planning of novel solutions may be organized top-down by the left DLPFC and by working memory processing in the medial prefrontal cortex. PMID:22349801

  15. Slow Progress in Dune (Left Front Wheel) (United States)


    The left front wheel of NASA's Mars Exploration Rover Opportunity makes slow but steady progress through soft dune material in this movie clip of frames taken by the rover's front hazard identification camera over a period of several days. The sequence starts on Opportunity's 460th martian day, or sol (May 10, 2005) and ends 11 days later. In eight drives during that period, Opportunity advanced a total of 26 centimeters (10 inches) while spinning its wheels enough to have driven 46 meters (151 feet) if there were no slippage. The motion appears to speed up near the end of the clip, but that is an artifact of individual frames being taken less frequently.

  16. Slow Progress in Dune (Left Rear Wheel) (United States)


    The left rear wheel of NASA's Mars Exploration Rover Opportunity makes slow but steady progress through soft dune material in this movie clip of frames taken by the rover's rear hazard identification camera over a period of several days. The sequence starts on Opportunity's 460th martian day, or sol (May 10, 2005) and ends 11 days later. In eight drives during that period, Opportunity advanced a total of 26 centimeters (10 inches) while spinning its wheels enough to have driven 46 meters (151 feet) if there were no slippage. The motion appears to speed up near the end of the clip, but that is an artifact of individual frames being taken less frequently.

  17. Psychotic Symptoms Associated with Left Caudate Infarction

    Directory of Open Access Journals (Sweden)

    Ying-Chih Cheng


    Full Text Available Psychotic symptoms following acquired brain lesion are relatively rare, and thus, the specific association linking such symptoms to the distinct brain structure remains unclear. The frontal–subcortical circuits are thought to modulate motor activity and human behavior, and have been reported to be associated with many neuropsychiatric symptoms. We herein report the case of a 77-year-old man without previous psychiatric disorder who developed a new onset of psychotic symptoms following left caudate infarction. The presented case supports the fact that psychosis might arise from alteration of the distinct brain structure. The functional impairment of the frontal–subcortical circuits may be a critical factor linking the pathogenesis of psychosis associated with acquired brain lesion.

  18. ODEs: is there anything left to do

    Energy Technology Data Exchange (ETDEWEB)

    Gear, C.W.


    Two decades ago many people thought that there was very little left to occupy the researcher in the numerical initial-value problem for ordinary differential equations, but there has since been an enormous increase in the effort devoted to this problem and related software. The question is whether everything is finally done so that more difficult areas can be studied. The development of numerical solution techniques is examined from the identification of a problem to the never-final preparation of automatic codes for the solution of classes of similar problems. A number of ODE problems that are only a part of the way along this path of development are discussed. These problems include ones with highly oscillatory solutions, ones with frequent discontinuities, and ones in which very little accuracy is needed (and which should be integrated at low cost). 4 figures.

  19. Master VISUALLY Excel 2010

    CERN Document Server

    Marmel, Elaine


    The complete visual reference on Excel basics. Aimed at visual learners who are seeking an all-in-one reference that provides in-depth coveage of Excel from a visual viewpoint, this resource delves into all the newest features of Excel 2010. You'll explore Excel with helpful step-by-step instructions that show you, rather than tell you, how to navigate Excel, work with PivotTables and PivotCharts, use macros to streamline work, and collaborate with other users in one document.: This two-color guide features screen shots with specific, numbered instructions so you can learn the actions you need

  20. VRML metabolic network visualizer. (United States)

    Rojdestvenski, Igor


    A successful date collection visualization should satisfy a set of many requirements: unification of diverse data formats, support for serendipity research, support of hierarchical structures, algorithmizability, vast information density, Internet-readiness, and other. Recently, virtual reality has made significant progress in engineering, architectural design, entertainment and communication. We experiment with the possibility of using the immersive abstract three-dimensional visualizations of the metabolic networks. We present the trial Metabolic Network Visualizer software, which produces graphical representation of a metabolic network as a VRML world from a formal description written in a simple SGML-type scripting language.

  1. Determination of Three-Dimensional Left Ventricle Motion to Analyze Ventricular Dyssyncrony in SPECT Images

    DEFF Research Database (Denmark)

    de Sá Rebelo, Marina; Aarre, Ann Kirstine Hummelgaard; Clemmesen, Karen-Louise


    A method to compute three-dimension (3D) left ventricle (LV) motion and its color coded visualization scheme for the qualitative analysis in SPECT images is proposed. It is used to investigate some aspects of Cardiac Resynchronization Therapy (CRT). The method was applied to 3D gated-SPECT images...... sets from normal subjects and patients with severe Idiopathic Heart Failure, before and after CRT. Color coded visualization maps representing the LV regional motion showed significant difference between patients and normal subjects. Moreover, they indicated a difference between the two groups....... Numerical results of regional mean values representing the intensity and direction of movement in radial direction are presented. A difference of one order of magnitude in the intensity of the movement on patients in relation to the normal subjects was observed. Quantitative and qualitative parameters gave...

  2. Effect of eye rotation on visual-field map onto superior colliculus and visual cortex. (United States)

    Gordon, B; Moran, J; Presson, J


    We used multiunit recording to assess the effect of rotating one eye approximately 90 degrees at about the time of normal eye opening. Rotation of the eye did not alter the topography of the retinal maps onto visual cortex or superior colliculus. The intorted eye drove cells at most recording points in the contralateral visual cortex and superior colliculus. In its ipsilateral colliculus the intorted eye drove cells at about 10% of the recording points; that is, the temporal retina of this eye was quite ineffective in driving collicular cells. In its ipsilateral cortex the intorted eye drove cells at about 30% of the recording sites. The unoperated eye drove cells at all locations in both colliculus and cortex on both sides of the brain. The effects of extorsion were studied only in the superior colliculus. Extorsion and intorsion produced similar results except that extorsion produced a less severe deficit in the ability of the temporal retina to drive cells in its ipsilateral colliculus. Cutting all the extraocular muscles without eye rotation was studied only in the colliculus and produced results similar to those produced by intorsion and extorsion. However, the temporal retina of the operated eye was more effective after muscle cut alone than after intorsion or extorsion. Forcing the animal to use the rotated right eye alone on alternate days during the first 3 mo of life did not decrease the deficits. Almost all recording sites in the right colliculus were driven only by the unoperated left eye. If the left eye was sutured when the right eye was rotated, only the right eye drove cells in the left colliculus, but the two eyes were about equally effective in the right colliculus; however, rather few sites in the right colliculus were binocularly driven. We conclude that both extraocular muscle section and eye rotation reduce the effectiveness of the uncrossed input from the operated eye to the superior colliculus and visual cortex. The effects on the superior

  3. Scientific visualization uncertainty, multifield, biomedical, and scalable visualization

    CERN Document Server

    Chen, Min; Johnson, Christopher; Kaufman, Arie; Hagen, Hans


    Based on the seminar that took place in Dagstuhl, Germany in June 2011, this contributed volume studies the four important topics within the scientific visualization field: uncertainty visualization, multifield visualization, biomedical visualization and scalable visualization. • Uncertainty visualization deals with uncertain data from simulations or sampled data, uncertainty due to the mathematical processes operating on the data, and uncertainty in the visual representation, • Multifield visualization addresses the need to depict multiple data at individual locations and the combination of multiple datasets, • Biomedical is a vast field with select subtopics addressed from scanning methodologies to structural applications to biological applications, • Scalability in scientific visualization is critical as data grows and computational devices range from hand-held mobile devices to exascale computational platforms. Scientific Visualization will be useful to practitioners of scientific visualization, ...

  4. The Visual System

    Medline Plus

    Full Text Available ... Glossary The Visual System Your Eyes’ Natural Defenses Eye Health and Safety First Aid Tips Healthy Vision Tips Protective Eyewear Sports and Your Eyes Fun Stuff Cool Eye Tricks Links to More ...

  5. Adaptive semantics visualization

    CERN Document Server

    Nazemi, Kawa


    This book introduces a novel approach for intelligent visualizations that adapts the different visual variables and data processing to human’s behavior and given tasks. Thereby a number of new algorithms and methods are introduced to satisfy the human need of information and knowledge and enable a usable and attractive way of information acquisition. Each method and algorithm is illustrated in a replicable way to enable the reproduction of the entire “SemaVis” system or parts of it. The introduced evaluation is scientifically well-designed and performed with more than enough participants to validate the benefits of the methods. Beside the introduced new approaches and algorithms, readers may find a sophisticated literature review in Information Visualization and Visual Analytics, Semantics and information extraction, and intelligent and adaptive systems. This book is based on an awarded and distinguished doctoral thesis in computer science.

  6. The Visual System

    Medline Plus

    Full Text Available ... support research, training, health information dissemination, and other programs with respect to blinding eye diseases, visual disorders, ... and Funding Extramural Research Division of Extramural Science Programs Division of Extramural Activities Extramural Contacts NEI Division ...

  7. Parallel Planes Information Visualization

    Energy Technology Data Exchange (ETDEWEB)


    This software presents a user-provided multivariate dataset as an interactive three dimensional visualization so that the user can explore the correlation between variables in the observations and the distribution of observations among the variables.

  8. The Visual System

    Medline Plus

    Full Text Available ... The Visual System Ever wonder how your eyes work? Watch this video to learn how you’re ... maintained by the NEI Office of Science Communications, Public Liaison, and Education. Technical questions about this website ...

  9. [Intraoperative multidimensional visualization]. (United States)

    Sperling, J; Kauffels, A; Grade, M; Alves, F; Kühn, P; Ghadimi, B M


    Modern intraoperative techniques of visualization are increasingly being applied in general and visceral surgery. The combination of diverse techniques provides the possibility of multidimensional intraoperative visualization of specific anatomical structures. Thus, it is possible to differentiate between normal tissue and tumor tissue and therefore exactly define tumor margins. The aim of intraoperative visualization of tissue that is to be resected and tissue that should be spared is to lead to a rational balance between oncological and functional results. Moreover, these techniques help to analyze the physiology and integrity of tissues. Using these methods surgeons are able to analyze tissue perfusion and oxygenation. However, to date it is not clear to what extent these imaging techniques are relevant in the clinical routine. The present manuscript reviews the relevant modern visualization techniques focusing on intraoperative computed tomography and magnetic resonance imaging as well as augmented reality, fluorescence imaging and optoacoustic imaging.

  10. The Visual System

    Medline Plus

    Full Text Available ... Video Series Glossary The Visual System Your Eyes’ Natural Defenses Eye Health and Safety First Aid Tips ... website is maintained by the NEI Office of Science Communications, Public Liaison, and Education. Technical questions about ...

  11. The Visual System

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    Full Text Available ... search for current job openings visit HHS USAJobs Home >> NEI for Kids >> The Visual System Listen All ... up to 28,800 times a day! NEI Home Contact Us A-Z Site Map NEI on ...

  12. The Visual System

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    Full Text Available ... Information Frequently asked questions Clinical Studies Publications Catalog Photos and Images Spanish Language Information Grants and Funding ... job openings visit HHS USAJobs Home >> NEI for Kids >> The Visual System Listen All About Vision About ...

  13. The Visual System

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    Full Text Available ... Fellowships NEI Summer Intern Program Diversity In Vision Research & Ophthalmology (DIVRO) Student ... All About Vision About the Eye Ask a Scientist Video Series Glossary The Visual System Your ...

  14. The Visual System

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    Full Text Available ... History of the NEI NEI 50th Anniversary NEI Women Scientists Advisory Committee (WSAC) Board of Scientific Counselors ... The Visual System Ever wonder how your eyes work? Watch this video to learn how you’re ...

  15. The Visual System

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    Full Text Available ... for Kids >> The Visual System Listen All About Vision About the Eye Ask a Scientist Video Series ... Eye Health and Safety First Aid Tips Healthy Vision Tips Protective Eyewear Sports and Your Eyes Fun ...

  16. The Visual System

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    Full Text Available ... of visual function, preservation of sight, and the special health problems and requirements of the blind.” News & ... Emily Y. Chew, M.D., Deputy Clinical Director Education Programs National Eye Health Education Program (NEHEP) Diabetic ...

  17. Visual Guided Navigation

    National Research Council Canada - National Science Library

    Banks, Martin


    .... Similarly, the problem of visual navigation is the recovery of an observer's self-motion with respect to the environment from the moving pattern of light reaching the eyes and the complex of extra...

  18. Principles of visual attention

    DEFF Research Database (Denmark)

    Bundesen, Claus; Habekost, Thomas

    The nature of attention is one of the oldest and most central problems in psychology. A huge amount of research has been produced on this subject in the last half century, especially on attention in the visual modality, but a general explanation has remained elusive. Many still view attention...... research as a field that is fundamentally fragmented. This book takes a different perspective and presents a unified theory of visual attention: the TVA model. The TVA model explains the many aspects of visual attention by just two mechanisms for selection of information: filtering and pigeonholing....... These mechanisms are described in a set of simple equations, which allow TVA to mathematically model a large number of classical results in the attention literature. The theory explains psychological and neuroscientific findings by the same equations; TVA is a complete theory of visual attention, linking mind...

  19. The Visual System

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    Full Text Available ... The Visual System Your Eyes’ Natural Defenses Eye Health and Safety First Aid Tips Healthy Vision Tips ... addressed to the NEI Website Manager . Department of Health and Human Services | The National Institutes of Health | ...

  20. Visualization in scientific computing

    National Research Council Canada - National Science Library

    Nielson, Gregory M; Shriver, Bruce D; Rosenblum, Lawrence J


    The purpose of this text is to provide a reference source to scientists, engineers, and students who are new to scientific visualization or who are interested in expanding their knowledge in this subject...

  1. Visualization Design Environment

    Energy Technology Data Exchange (ETDEWEB)

    Pomplun, A.R.; Templet, G.J.; Jortner, J.N.; Friesen, J.A.; Schwegel, J.; Hughes, K.R.


    Improvements in the performance and capabilities of computer software and hardware system, combined with advances in Internet technologies, have spurred innovative developments in the area of modeling, simulation and visualization. These developments combine to make it possible to create an environment where engineers can design, prototype, analyze, and visualize components in virtual space, saving the time and expenses incurred during numerous design and prototyping iterations. The Visualization Design Centers located at Sandia National Laboratories are facilities built specifically to promote the ''design by team'' concept. This report focuses on designing, developing and deploying this environment by detailing the design of the facility, software infrastructure and hardware systems that comprise this new visualization design environment and describes case studies that document successful application of this environment.

  2. Visualizing guided tours

    DEFF Research Database (Denmark)

    Poulsen, Signe Herbers; Fjord-Larsen, Mads; Hansen, Frank Allan

    This paper identifies several problems with navigating and visualizing guided tours in traditional hypermedia systems. We discuss solutions to these problems, including the representation of guided tours as 3D metro maps with content preview. Issues regarding navigation and disorientation...

  3. The Visual System

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    Full Text Available ... of the NEI NEI 50th Anniversary NEI Women Scientists Advisory Committee (WSAC) Board of Scientific Counselors National ... All About Vision About the Eye Ask a Scientist Video Series Glossary The Visual System Your Eyes’ ...

  4. Disposable Visual Sensor

    National Research Council Canada - National Science Library

    Amidon, Charles P


    A disposable visual sensor includes a body defining an enclosed chamber, a power source mounted in the camber, an on-off switch mounted on the body and accessible from outside the body, a processor...

  5. The Visual System

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    Full Text Available ... visual function, preservation of sight, and the special health problems and requirements of the blind.” News & Events Events Calendar NEI Press Releases News from NEI Grantees Spokesperson bios ... Frequently asked questions Clinical Studies Publications Catalog ...

  6. Fully automatic segmentation of left ventricular anatomy in 3-D LGE-MRI. (United States)

    Kurzendorfer, Tanja; Forman, Christoph; Schmidt, Michaela; Tillmanns, Christoph; Maier, Andreas; Brost, Alexander


    The current challenge for electrophysiology procedures, targeting the left ventricle, is the localization and qualification of myocardial scar. Late gadolinium enhanced magnetic resonance imaging (LGE-MRI) is the current gold standard to visualize regions of myocardial infarction. Commonly, a stack of 2-D images is acquired of the left ventricle in short-axis orientation. Recently, 3-D LGE-MRI methods were proposed that continuously cover the whole heart with a high resolution within a single acquisition. The acquisition promises an accurate quantification of the myocardium to the extent of myocardial scarring. The major challenge arises in the analysis of the resulting images, as the accurate segmentation of the myocardium is a requirement for a precise scar tissue quantification. In this work, we propose a novel approach for fully automatic left ventricle segmentation in 3-D whole-heart LGE-MRI, to address this limitation. First, a two-step registration is performed to initialize the left ventricle. In the next step, the principal components are computed and a pseudo short axis view of the left ventricle is estimated. The refinement of the endocardium and epicardium is performed in polar space. Prior knowledge for shape and inter-slice smoothness is used during segmentation. The proposed method was evaluated on 30 clinical 3-D LGE-MRI datasets from individual patients obtained at two different clinical sites and were compared to gold standard segmentations of two clinical experts. This comparison resulted in a Dice coefficient of 0.83 for the endocardium and 0.80 for the epicardium. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. Visual evoked potentials and selective attention to points in space (United States)

    Van Voorhis, S.; Hillyard, S. A.


    Visual evoked potentials (VEPs) were recorded to sequences of flashes delivered to the right and left visual fields while subjects responded promptly to designated stimuli in one field at a time (focused attention), in both fields at once (divided attention), or to neither field (passive). Three stimulus schedules were used: the first was a replication of a previous study (Eason, Harter, and White, 1969) where left- and right-field flashes were delivered quasi-independently, while in the other two the flashes were delivered to the two fields in random order (Bernoulli sequence). VEPs to attended-field stimuli were enhanced at both occipital (O2) and central (Cz) recording sites under all stimulus sequences, but different components were affected at the two scalp sites. It was suggested that the VEP at O2 may reflect modality-specific processing events, while the response at Cz, like its auditory homologue, may index more general aspects of selective attention.

  8. Visualization of Personalization Information


    Almerfors, Mattias


    There has been an increasing use of Internet as an information source and also as a new channel for business-to-business and business-to-consumer communication. This has lead to an increasing need for understanding web traffic and especially a growing need for analyzing this traffic, which demands new analysis tools. The objective for this study was to create an application framework for visualizing XML-formatted data representing web traffic reports. Visualization in two dimensions is create...

  9. Understanding Visual Novel As Artwork of Visual Communication Design

    Directory of Open Access Journals (Sweden)

    Dendi Pratama


    Full Text Available Visual Novel is a kind of audiovisual game that offers visual strength through the narrative and visual characters. The developer community of Visual Novel (VN Project Indonesia indicated a limited local game developer that produces Visual Novel of Indonesia. In addition, Indonesian Visual Novel production was also more influenced by the style of anime or manga from Japan. Actually, Visual Novel is part of the potential of  creative industries products. The study is to formulate the problem, how to understand Visual Novel as artwork of visual communication design, especially among students? This research is a case study conducted on visual communication design student at the University Indraprasta PGRI Jakarta. The results showed low levels of knowledge, understanding, and experience of  the Visual Novel game, which is below 50%. Qualitative and quantitative methods combined with structural semiotic approach is used to describe the elements of the design and the signs structure at the Visual Novel. This research can be a scientific reference for further introduce and encourage an understanding of Visual Novel as artwork of Visual Communication Design. In addition, the results may add to the knowledge of  society, and encourage the development of Visual Novel artwork that  reflect the culture of Indonesia. Visual Novel adalah sejenis permainan audiovisual yang menawarkan kekuatan visual melalui narasi dan karakter visual. Data dari komunitas pengembang Visual Novel (VN Project Indonesia menunjukkan masih terbatasnya pengembang game lokal yang memproduksi Visual Novel Indonesia. Selain itu, produksi Visual Novel Indonesia juga lebih banyak dipengaruhi oleh gaya anime dan manga dari Jepang. Padahal Visual Novel adalah bagian dari produk industri kreatif yang potensial. Studi ini merumuskan masalah, bagaimana memahami Visual Novel sebagai karya seni desain komunikasi visual, khususnya di kalangan mahasiswa? Penelitian ini merupakan studi kasus

  10. A case of a pseudo colonic mass causing gastrointestinal bleeding in a patient with a left ventricular assist device (United States)

    Huntington, Justin T.; Plews, Robert L.; Mansfield, Sara A.; Drosdeck, Joseph M.; Evans, David C.


    There are many complications associated with the left ventricular assist devices (LVADs), including gastrointestinal bleeding (GIB). We present a case of a pseudo colonic mass visualized on colonoscopy during workup for GIB in an LVAD patient necessitating a right colectomy with final pathology negative for malignancy. A review of the literature in regards to the pathology, diagnosis, and treatment of this interesting condition is included. PMID:27722118

  11. The whereabouts of visual attention: Involuntary attentional bias toward the default gaze direction. (United States)

    Nakashima, Ryoichi; Kumada, Takatsune


    This study proposed and verified a new hypothesis on the relationship between gaze direction and visual attention: attentional bias by default gaze direction based on eye-head coordination. We conducted a target identification task in which visual stimuli appeared briefly to the left and right of a fixation cross. In Experiment 1, the direction of the participant's head (aligned with the body) was manipulated to the left, front, or right relative to a central fixation point. In Experiment 2, head direction was manipulated to the left, front, or right relative to the body direction. This manipulation was based on results showing that bias of eye position distribution was highly correlated with head direction. In both experiments, accuracy was greater when the target appeared at a position where the eyes would potentially be directed. Consequently, eye-head coordination influences visual attention. That is, attention can be automatically biased toward the location where the eyes tend to be directed.

  12. Visualization of multidimensional database (United States)

    Lee, Chung


    The concept of multidimensional databases has been extensively researched and wildly used in actual database application. It plays an important role in contemporary information technology, but due to the complexity of its inner structure, the database design is a complicated process and users are having a hard time fully understanding and using the database. An effective visualization tool for higher dimensional information system helps database designers and users alike. Most visualization techniques focus on displaying dimensional data using spreadsheets and charts. This may be sufficient for the databases having three or fewer dimensions but for higher dimensions, various combinations of projection operations are needed and a full grasp of total database architecture is very difficult. This study reviews existing visualization techniques for multidimensional database and then proposes an alternate approach to visualize a database of any dimension by adopting the tool proposed by Kiviat for software engineering processes. In this diagramming method, each dimension is represented by one branch of concentric spikes. This paper documents a C++ based visualization tool with extensive use of OpenGL graphics library and GUI functions. Detailed examples of actual databases demonstrate the feasibility and effectiveness in visualizing multidimensional databases.

  13. Cosmography and Data Visualization (United States)

    Pomarède, Daniel; Courtois, Hélène M.; Hoffman, Yehuda; Tully, R. Brent


    Cosmography, the study and making of maps of the universe or cosmos, is a field where visual representation benefits from modern three-dimensional visualization techniques and media. At the extragalactic distance scales, visualization is contributing to our understanding of the complex structure of the local universe in terms of spatial distribution and flows of galaxies and dark matter. In this paper, we report advances in the field of extragalactic cosmography obtained using the SDvision visualization software in the context of the Cosmicflows Project. Here, multiple visualization techniques are applied to a variety of data products: catalogs of galaxy positions and galaxy peculiar velocities, reconstructed velocity field, density field, gravitational potential field, velocity shear tensor viewed in terms of its eigenvalues and eigenvectors, envelope surfaces enclosing basins of attraction. These visualizations, implemented as high-resolution images, videos, and interactive viewers, have contributed to a number of studies: the cosmography of the local part of the universe, the nature of the Great Attractor, the discovery of the boundaries of our home supercluster of galaxies Laniakea, the mapping of the cosmic web, and the study of attractors and repellers.

  14. Quantized Visual Awareness

    Directory of Open Access Journals (Sweden)

    W Alexander Escobar


    Full Text Available The proposed model holds that, at its most fundamental level, visual awareness is quantized. That is to say that visual awareness arises as individual bits of awareness through the action of neural circuits with hundreds to thousands of neurons in at least the human striate cortex. Circuits with specific topologies will reproducibly result in visual awareness that correspond to basic aspects of vision like color, motion and depth. These quanta of awareness (qualia are produced by the feedforward sweep that occurs through the geniculocortical pathway but are not integrated into a conscious experience until recurrent processing from centers like V4 or V5 select the appropriate qualia being produced in V1 to create a percept. The model proposed here has the potential to shift the focus of the search for visual awareness to the level of microcircuits and these likely exist across the kingdom Animalia. Thus establishing qualia as the fundamental nature of visual awareness will not only provide a deeper understanding of awareness, but also allow for a more quantitative understanding of the evolution of visual awareness throughout the animal kingdom.

  15. Quantized visual awareness (United States)

    Escobar, W. A.


    The proposed model holds that, at its most fundamental level, visual awareness is quantized. That is to say that visual awareness arises as individual bits of awareness through the action of neural circuits with hundreds to thousands of neurons in at least the human striate cortex. Circuits with specific topologies will reproducibly result in visual awareness that correspond to basic aspects of vision like color, motion, and depth. These quanta of awareness (qualia) are produced by the feedforward sweep that occurs through the geniculocortical pathway but are not integrated into a conscious experience until recurrent processing from centers like V4 or V5 select the appropriate qualia being produced in V1 to create a percept. The model proposed here has the potential to shift the focus of the search for visual awareness to the level of microcircuits and these likely exist across the kingdom Animalia. Thus establishing qualia as the fundamental nature of visual awareness will not only provide a deeper understanding of awareness, but also allow for a more quantitative understanding of the evolution of visual awareness throughout the animal kingdom. PMID:24319436

  16. Visual electrophysiology in children

    Directory of Open Access Journals (Sweden)

    Jelka Brecelj


    Full Text Available Background: Electrophysiological assessment of vision in children helps to recognise abnormal development of the visual system when it is still susceptible to medication and eventual correction. Visual electrophysiology provides information about the function of the retina (retinal pigment epithelium, cone and rod receptors, bipolar, amacrine, and ganglion cells, optic nerve, chiasmal and postchiasmal visual pathway, and visual cortex.Methods: Electroretinograms (ERG and visual evoked potentials (VEP are recorded non-invasively; in infants are recorded simultaneously ERG with skin electrodes, while in older children separately ERG with HK loop electrode in accordance with ISCEV (International Society for Clinical Electrophysiology of Vision recommendations.Results: Clinical and electrophysiological changes in children with nystagmus, Leber’s congenital amaurosis, achromatopsia, congenital stationary night blindness, progressive retinal dystrophies, optic nerve hypoplasia, albinism, achiasmia, optic neuritis and visual pathway tumours are presented.Conclusions: Electrophysiological tests can help to indicate the nature and the location of dysfunction in unclear ophthalmological and/or neurological cases.

  17. [Lesion of extrahippocampal cortices of left medial temporal lobe: a case report]. (United States)

    Spada, J A; Galíndez, C; Spada, A

    The cortex of medial temporal lobe is a group of different allocortical fields which included the hippocampal formation (dentate gyrus, hippocampus proper, and subicular complex) and extrahippocampal cortices (entorhinal, perirhinal, and parahippocampal). It is widely accepted that both of them play an important role in memory process. In humans, several reports indicates that damage to the hippocampus alone would lead to a clinically significant amnesia; when the injuries are more extensive others cognitive disorders, as those related to visual sphere, make worse the clinic picture, and some of these cases were reported as associative visual agnosias. Nevertheless, although evidence from animal studies points to the importance of the extrahippocampal medial temporal lobe cortices in order to recognise visual stimuli, such involvement has not been demonstrated in humans. A 44 year-old male who consulted us because they had lost about of '80% of his vision' after a stroke. Ophthalmological examination was entirely within normal limits, but neuropsychological test put in evidence difficulties in the visuo-verbal naming, discrimination of superposed images, recognition of faces and, mainly, in the test of immediate and deferred visual memory. Anterograde memory impairment was also revealed. Magnetic resonance imaging showed a lesion of left entorhinal, perirhinal and parahippocampal cortices. We suggest, in relation to anatomical evidences, that isolation of hippocampus is responsible for symptomatollogy of our patient.

  18. What's Left of the Left-Right Dimension? Why the Economic Policy Positions of Europeans Do Not Fit the Left-Right Dimension. (United States)

    Otjes, Simon


    In political science the economic left-right dimension plays a central role. A growing body of evidence shows that the economic policy preferences of a large segment of citizens do not scale sufficiently. Using Mokken scale analysis, this study determines the causes of this phenomenon. Differences in the extent to which the economic policy preferences of citizens fit the left-right dimension can be explained in terms of the interaction between individual level and political system-level variables: citizens who spend more attention to politicians with views that conform to the left-right dimension, have views that conform to the left-right dimension. There is also a role for the legacy of communist dictatorship: citizens who were socialised in democratic countries have views that fit the left-right dimension better than those socialised during communism.

  19. Brain activation in response to randomized visual stimulation as obtained from conjunction and differential analysis: an fMRI study (United States)

    Nasaruddin, N. H.; Yusoff, A. N.; Kaur, S.


    The objective of this multiple-subjects functional magnetic resonance imaging (fMRI) study was to identify the common brain areas that are activated when viewing black-and-white checkerboard pattern stimuli of various shapes, pattern and size and to investigate specific brain areas that are involved in processing static and moving visual stimuli. Sixteen participants viewed the moving (expanding ring, rotating wedge, flipping hour glass and bowtie and arc quadrant) and static (full checkerboard) stimuli during an fMRI scan. All stimuli have black-and-white checkerboard pattern. Statistical parametric mapping (SPM) was used in generating brain activation. Differential analyses were implemented to separately search for areas involved in processing static and moving stimuli. In general, the stimuli of various shapes, pattern and size activated multiple brain areas mostly in the left hemisphere. The activation in the right middle temporal gyrus (MTG) was found to be significantly higher in processing moving visual stimuli as compared to static stimulus. In contrast, the activation in the left calcarine sulcus and left lingual gyrus were significantly higher for static stimulus as compared to moving stimuli. Visual stimulation of various shapes, pattern and size used in this study indicated left lateralization of activation. The involvement of the right MTG in processing moving visual information was evident from differential analysis, while the left calcarine sulcus and left lingual gyrus are the areas that are involved in the processing of static visual stimulus.

  20. Functional and structural comparison of visual lateralization in birds – similar but still different

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    Martina eManns


    Full Text Available Vertebrate brains display physiological and anatomical left-right differences, which are related to hemispheric dominances for specific functions. Functional lateralizations likely rely on structural left-right differences in intra- and interhemispheric connectivity patterns that develop in tight gene-environment interactions. The visual systems of chickens and pigeons show that asymmetrical light stimulation during ontogeny induces a dominance of the left hemisphere for visuomotor control that is paralleled by projection asymmetries within the ascending visual pathways. But structural asymmetries vary essentially between both species concerning the affected pathway (thalamo- vs. tectofugal system, constancy of effects (transient vs. permanent, and the hemisphere receiving stronger bilateral input (right vs. left. These discrepancies suggest that at least two aspects of visual processes are influenced by asymmetric light stimulation: 1. Visuomotor dominance develops within the ontogenetically stronger stimulated hemisphere but not necessarily in the one receiving stronger bottom-up input. As a secondary consequence of asymmetrical light experience, lateralized top-down mechanisms play a critical role in the emergence of hemispheric dominance. 2. Ontogenetic light experiences may affect the dominant use of left- and right-hemispheric strategies. Evidences from social and spatial cognition tasks indicate that chickens rely more on a right-hemispheric global strategy whereas pigeons display a dominance of the left hemisphere. Thus, behavioural asymmetries are linked to a stronger bilateral input to the right hemisphere in chickens but to the left one in pigeons. The degree of bilateral visual input may determine the dominant visual processing strategy when redundant encoding is possible. This analysis supports that environmental stimulation affects the balance between hemispheric-specific processing by lateralized interactions of bottom-up and top