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Kim S, Nam K. Decoding foveal word recognition: the role of interhemispheric inhibition in bilateral hemispheric processing. Front Psychol 2023; 14:1293529. [PMID: 38098522 PMCID: PMC10720635 DOI: 10.3389/fpsyg.2023.1293529] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2023] [Accepted: 11/09/2023] [Indexed: 12/17/2023] Open
Abstract
Extant research has largely favored the Split Fovea Theory (SFT) over the Bilateral Projection Theory (BPT) in the context of foveal word recognition. SFT posits that during foveal fixation, letters in the left and right visual fields are projected to their respective contralateral hemispheres, thereby facilitating a division of labor across the bilateral hemispheres. This division may serve as a regulatory mechanism to mitigate redundant processing in both hemispheres. The present investigation conducted two experiments utilizing Korean visual words to explore whether this hemispheric division in foveal word recognition is a strategy to circumvent potential interhemispheric inhibition arising from duplicated processing. Experiment 1 established the suitability of Korean visual words for studies involving both unilateral and bilateral presentations. Experiment 2 revealed that the split presentation of a word elicited greater accuracy compared to its identical presentation in the bilateral visual fields. These findings lend credence to the notion that interhemispheric inhibition may drive the hemispheres to engage in divided labor, thereby reducing processing redundancy in foveal word recognition.
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Affiliation(s)
- Sangyub Kim
- Wisdom Science Center, Korea University, Seoul, Republic of Korea
| | - Kichun Nam
- School of Psychology, Korea University, Seoul, Republic of Korea
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2
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Predicting visual perceivability of scene objects through spatio-temporal modeling of retinal receptive fields. Neurocomputing 2021. [DOI: 10.1016/j.neucom.2020.07.119] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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3
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Bellocchi S, Ducrot S. "Same, same but different": The optimal viewing position effect in developmental dyslexia, developmental coordination disorder and comorbid disorders. DYSLEXIA (CHICHESTER, ENGLAND) 2021; 27:294-311. [PMID: 34080259 DOI: 10.1002/dys.1688] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Revised: 02/26/2021] [Accepted: 05/15/2021] [Indexed: 06/12/2023]
Abstract
The optimal viewing position (OVP) effect indicates that words are identified most quickly when the eyes fixate near the word centre in alphabetic languages. In two studies, we tested OVP in typically developing readers and children with developmental dyslexia (DD), developmental coordination disorder (DCD) and with both disorders (DD + DCD), using a variable-viewing-position technique. Study 1 showed that typically developing readers had developed highly automatized procedures of left-to-right attentional scanning resulting in an inverted J-shape VP curve comparable to what is observed in adult readers and that dyslexics showed non-prototypical one. In Study 2, we observed more typical procedures of left-to-right attentional scanning in children with DCD, isolated or comorbid, compared to DD. Moreover, given the absence of significant group differences between children with DD + DCD and children with isolated DD or DCD, our results reinforce the idea that the comorbid condition does not add to the severity of OVP anomalies. We then concluded that OVP atypicalities are specific to children with DD. Finally, we discussed the usefulness of the OVP effect as a clinical tool to identify possible OVP atypicalities that could be specific of some neurodevelopmental disorders (i.e., DD, DCD or DCD + DD).
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Affiliation(s)
- Stéphanie Bellocchi
- Laboratoire EPSYLON EA 4556, Univ Paul Valéry Montpellier 3, Montpellier, France
| | - Stéphanie Ducrot
- Laboratoire Parole et Langage, Aix-Marseille University & CNRS, Aix-en-Provence, France
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4
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Harrison MT, Strother L. Does face-selective cortex show a left visual field bias for centrally-viewed faces? Neuropsychologia 2021; 159:107956. [PMID: 34265343 DOI: 10.1016/j.neuropsychologia.2021.107956] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Revised: 07/07/2021] [Accepted: 07/09/2021] [Indexed: 12/29/2022]
Abstract
The left half of a centrally-viewed face contributes more strongly to recognition performance than the right. This left visual field (LVF) advantage is typically attributed to an untested assumption that face-selective cortex in the right hemisphere (RH) exhibits a contralateral bias, even for centrally-viewed faces. We tested the validity of this assumption using a behavioral measure of the LVF advantage and an fMRI experiment that measured laterality of face-selective cortex and neural contralateral bias. In the behavioral experiment, participants performed a chimeric face-matching task (Harrison and Strother, 2019). In the fMRI experiment, participants viewed chimeric faces comprised of face halves that either repeated or changed simultaneously in both hemifields, or repeated in one hemifield and changed in the other. This enabled us to measure lateralization of fMRI face-repetition suppression and hemifield-specific half-face sensitivity in face-selective cortex. We found that LVF bias in the fusiform face area (FFA) and right-lateralization of the FFA for changing versus repeated faces were both positively correlated with a behavioral measure of the LVF advantage for upright (but not inverted) faces. Results from regression analyses showed that LVF bias in the right FFA and FFA laterality make separable contributions to the prediction of our behavioral measure of the LVF bias for upright faces. Our results confirm a ubiquitous but previously untested assumption that RH superiority combined with contralateral bias in face-selective cortex explains the LVF advantage in face recognition. Specifically, our results show that neural LVF bias in the right FFA is sufficient to explain the relationship between FFA laterality and the perceptual LVF bias for centrally-viewed faces.
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Affiliation(s)
- Matthew T Harrison
- University of Nevada Reno Institute for Neuroscience, Department of Psychology, MS0296 1664 N. Virginia Street Reno, NV, 89557, USA.
| | - Lars Strother
- University of Nevada Reno Institute for Neuroscience, Department of Psychology, MS0296 1664 N. Virginia Street Reno, NV, 89557, USA
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5
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Abstract
Alexia refers to a reading disorder caused by some form of acquired brain pathology, most commonly a stroke or tumor, in a previously literate subject. In neuropsychology, a distinction is made between central alexia (commonly seen in aphasia) and peripheral alexia (a perceptual or attentional deficit). The prototypical peripheral alexia is alexia without agraphia (pure alexia), where patients can write but are impaired in reading words and letters. Pure alexia is associated with damage to the left ventral occipitotemporal cortex (vOT) or its connections. Hemianopic alexia is associated with less extensive occipital damage and is caused by a visual field defect, which creates problems reading longer words and passages of text. Reading impairment can also arise due to attentional deficits, most commonly following right hemisphere or bilateral lesions. Studying patients with alexia, along with functional imaging studies of normal readers, has improved our understanding of the neurobiological processes involved in reading. A key question is whether an area in the left ventral occipitotemporal cortex is specialized for or selectively involved in word processing, or whether reading relies on tuning of more general purpose perceptual areas. Reading deficits may also be observed in dementia and traumatic brain injury, but often with less consistent deficit patterns than in patients with focal lesions.
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Affiliation(s)
- Randi Starrfelt
- Department of Psychology, University of Copenhagen, Copenhagen, Denmark.
| | - Zoe Woodhead
- Department of Experimental Psychology, University of Oxford, Oxford, United Kingdom
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6
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Abstract
Humans are able to integrate pre- and postsaccadic percepts of an object across saccades to maintain perceptual stability. Previous studies have used Maximum Likelihood Estimation (MLE) to determine that integration occurs in a near-optimal manner. Here, we compared three different models to investigate the mechanism of integration in more detail: an early noise model, where noise is added to the pre- and postsaccadic signals before integration occurs; a late-noise model, where noise is added to the integrated signal after integration occurs; and a temporal summation model, where integration benefits arise from the longer transsaccadic presentation duration compared to pre- and postsaccadic presentation only. We also measured spatiotemporal aspects of integration to determine whether integration can occur for very brief stimulus durations, across two hemifields, and in spatiotopic and retinotopic coordinates. Pre-, post-, and transsaccadic performance was measured at different stimulus presentation durations, both at the saccade target and a location where the pre- and postsaccadic stimuli were presented in different hemifields across the saccade. Results showed that for both within- and between-hemifields conditions, integration could occur when pre- and postsaccadic stimuli were presented only briefly, and that the pattern of integration followed an early noise model. Whereas integration occurred when the pre- and post-saccadic stimuli were presented in the same spatiotopic coordinates, there was no integration when they were presented in the same retinotopic coordinates. This contrast suggests that transsaccadic integration is limited by early, independent, sensory noise acting separately on pre- and postsaccadic signals.
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Affiliation(s)
- Emma E M Stewart
- Experimental and Biological Psychology, University of Marburg, Marburg, Germany
| | - Alexander C Schütz
- Experimental and Biological Psychology, University of Marburg, Marburg, Germany
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7
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Does right hemisphere superiority sufficiently explain the left visual field advantage in face recognition? Atten Percept Psychophys 2019; 82:1205-1220. [DOI: 10.3758/s13414-019-01896-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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8
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Chen CY, Hoffmann KP, Distler C, Hafed ZM. The Foveal Visual Representation of the Primate Superior Colliculus. Curr Biol 2019; 29:2109-2119.e7. [PMID: 31257138 DOI: 10.1016/j.cub.2019.05.040] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Revised: 05/01/2019] [Accepted: 05/17/2019] [Indexed: 11/17/2022]
Abstract
A defining feature of the primate visual system is its foveated nature. Processing of foveal retinal input is important not only for high-quality visual scene analysis but also for ensuring precise, albeit tiny, gaze shifts during high-acuity visual tasks. The representations of foveal retinal input in the primate lateral geniculate nucleus and early visual cortices have been characterized. However, how such representations translate into precise eye movements remains unclear. Here, we document functional and structural properties of the foveal visual representation of the midbrain superior colliculus. We show that the superior colliculus, classically associated with extra-foveal spatial representations needed for gaze shifts, is highly sensitive to visual input impinging on the fovea. The superior colliculus also represents such input in an orderly and very specific manner, and it magnifies the representation of foveal images in neural tissue as much as the primary visual cortex does. The primate superior colliculus contains a high-fidelity visual representation, with large foveal magnification, perfectly suited for active visuomotor control and perception.
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Affiliation(s)
- Chih-Yang Chen
- Werner Reichardt Centre for Integrative Neuroscience, Tuebingen University, Tuebingen 72076, Germany; Hertie Institute for Clinical Brain Research, Tuebingen University, Tuebingen 72076, Germany
| | - Klaus-Peter Hoffmann
- Research Department of Neuroscience, Ruhr University Bochum, Bochum 44801, Germany
| | - Claudia Distler
- Department of General Zoology and Neurobiology, Ruhr University Bochum, Bochum 44801, Germany
| | - Ziad M Hafed
- Werner Reichardt Centre for Integrative Neuroscience, Tuebingen University, Tuebingen 72076, Germany; Hertie Institute for Clinical Brain Research, Tuebingen University, Tuebingen 72076, Germany.
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9
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10
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Scott KM. Split-Brain Babies? Differences in Representation of Bilaterally and Unilaterally Presented Visual Stimuli in Infancy. Front Psychol 2019; 9:2758. [PMID: 30778325 PMCID: PMC6369161 DOI: 10.3389/fpsyg.2018.02758] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Accepted: 12/20/2018] [Indexed: 11/17/2022] Open
Abstract
Information needed for perception and action is often distributed across the two hemispheres of the human brain. During development, representations lateralized due to topographic sensory maps may be available independently before they can be integrated across hemispheres. These studies (total N = 211) investigate visual interhemispheric integration in two domains in infancy. In Experiment 1, infants (8-14 months) showed stronger evidence of representing the equality of two shapes when the shapes were presented in the same visual hemifield. In Experiments 2-4, infants (10-19 months) showed evidence of greater familiarization when shown 16 dots in one hemifield than when shown 8 dots in each hemifield. The possibility that interhemispheric integration poses an unusually late-resolved challenge in infant vision is discussed.
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Affiliation(s)
- Kimberly M. Scott
- Early Childhood Cognition Lab, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA, United States
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11
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Lu Q, Wang X, Li L, Qiu B, Wei S, Sabel BA, Zhou Y. Visual rehabilitation training alters attentional networks in hemianopia: An fMRI study. Clin Neurophysiol 2018; 129:1832-1841. [PMID: 29981958 DOI: 10.1016/j.clinph.2018.05.027] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Revised: 05/17/2018] [Accepted: 05/28/2018] [Indexed: 01/15/2023]
Abstract
OBJECTIVE Hemianopia is a visual field defect following post-chiasmatic damage. We now applied functional magnetic resonance imaging (fMRI) in hemianopic patients before and after visual rehabilitation training (VRT) to examine the impact of VRT on attentional function networks. METHODS Seven chronic hemianopic patients with post- chiasmatic lesions carried out a VRT for five weeks under fixation control. Before vs. after intervention, we assessed the area of residual vision (ARV), contrast sensitivity function (CSF) and functional MRI data and correlated them with each other. RESULTS VRT significantly improved the visual function of grating detection at the training location. Using fMRI, we found that the training led to a strengthening of connectivity between the right temporoparietal junction (rTPJ) to the insula and the anterior cingulate cortex (ACC), all of which belong to the cortical attentional network. However, no significant correlation between alterations of brain activity and improvements of either CSF or ARV was found. CONCLUSION Visual rehabilitation training partially restored the deficient visual field sectors and could improve attentional network function in hemianopia. SIGNIFICANCE Our MRI results highlight the role of attention and the rTPJ activation as one, but not the only, component of VRT in hemianopia.
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Affiliation(s)
- Qilin Lu
- Hefei National Laboratory for Physical Sciences at Microscale and School of Life Science, University of Science and Technology of China, Hefei, Anhui 230027, PR China; State Key Laboratory of Brain and Cognitive Science, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, PR China
| | - Xiaoxiao Wang
- Hefei National Laboratory for Physical Sciences at Microscale and School of Life Science, University of Science and Technology of China, Hefei, Anhui 230027, PR China; State Key Laboratory of Brain and Cognitive Science, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, PR China; Centers for Biomedical Engineering, University of Science and Technology of China, Hefei, PR China
| | - Lin Li
- Hefei National Laboratory for Physical Sciences at Microscale and School of Life Science, University of Science and Technology of China, Hefei, Anhui 230027, PR China; State Key Laboratory of Brain and Cognitive Science, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, PR China
| | - Bensheng Qiu
- Centers for Biomedical Engineering, University of Science and Technology of China, Hefei, PR China
| | - Shihui Wei
- Department of Ophthalmology, Chinese PLA General Hospital, Beijing, PR China.
| | - Bernhard A Sabel
- Institute of Medical Psychology, Medical Faculty, Otto-von-Guericke University of Magdeburg, Germany
| | - Yifeng Zhou
- Hefei National Laboratory for Physical Sciences at Microscale and School of Life Science, University of Science and Technology of China, Hefei, Anhui 230027, PR China; State Key Laboratory of Brain and Cognitive Science, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, PR China.
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12
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Phu J, Kalloniatis M, Khuu SK. Reducing Spatial Uncertainty Through Attentional Cueing Improves Contrast Sensitivity in Regions of the Visual Field With Glaucomatous Defects. Transl Vis Sci Technol 2018; 7:8. [PMID: 29600116 PMCID: PMC5868861 DOI: 10.1167/tvst.7.2.8] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Accepted: 01/21/2018] [Indexed: 11/24/2022] Open
Abstract
Purpose Current clinical perimetric test paradigms present stimuli randomly to various locations across the visual field (VF), inherently introducing spatial uncertainty, which reduces contrast sensitivity. In the present study, we determined the extent to which spatial uncertainty affects contrast sensitivity in glaucoma patients by minimizing spatial uncertainty through attentional cueing. Methods Six patients with open-angle glaucoma and six healthy subjects underwent laboratory-based psychophysical testing to measure contrast sensitivity at preselected locations at two eccentricities (9.5° and 17.5°) with two stimulus sizes (Goldmann sizes III and V) under different cueing conditions: 1, 2, 4, or 8 points verbally cued. Method of Constant Stimuli and a single-interval forced-choice procedure were used to generate frequency of seeing (FOS) curves at locations with and without VF defects. Results At locations with VF defects, cueing minimizes spatial uncertainty and improves sensitivity under all conditions. The effect of cueing was maximal when one point was cued, and rapidly diminished when more points were cued (no change to baseline with 8 points cued). The slope of the FOS curve steepened with reduced spatial uncertainty. Locations with normal sensitivity in glaucomatous eyes had similar performance to that of healthy subjects. There was a systematic increase in uncertainty with the depth of VF loss. Conclusions Sensitivity measurements across the VF are negatively affected by spatial uncertainty, which increases with greater VF loss. Minimizing uncertainty can improve sensitivity at locations of deficit. Translational Relevance Current perimetric techniques introduce spatial uncertainty and may therefore underestimate sensitivity in regions of VF loss.
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Affiliation(s)
- Jack Phu
- Centre for Eye Health, University of New South Wales, Kensington, NSW, Australia.,School of Optometry and Vision Science, University of New South Wales, Kensington, NSW, Australia
| | - Michael Kalloniatis
- Centre for Eye Health, University of New South Wales, Kensington, NSW, Australia.,School of Optometry and Vision Science, University of New South Wales, Kensington, NSW, Australia
| | - Sieu K Khuu
- School of Optometry and Vision Science, University of New South Wales, Kensington, NSW, Australia
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13
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Liu S, Tse PU, Cavanagh P. Meridian interference reveals neural locus of motion-induced position shifts. J Neurophysiol 2018. [PMID: 29513148 DOI: 10.1152/jn.00876.2017] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
When a Gabor patch moves along a path in one direction while its internal texture drifts orthogonally to this path, it can appear to deviate from its physical path by 45° or more. This double-drift illusion is different from other motion-induced position shift effects in several ways: it has an integration period of over a second; the illusory displacement that accumulates over a second or more is orthogonal to rather than along the motion path; the perceptual deviations are much larger; and they have little or no effect on eye movements to the target. In this study we investigated the underlying neural mechanisms of the motion integration and position processing for this double-drift stimulus by testing possible anatomical constraints on its magnitude. We found that the illusion was reduced at the vertical and horizontal meridians when the perceptual path would cross or be driven toward the meridian, but not at other locations or other motion directions. The disruption of the accumulation of the position error at both the horizontal and vertical meridians suggests a central role of quadrantic areas in the generation of this type of motion-induced position shift. NEW & NOTEWORTHY The remarkably strong double-drift illusion is disrupted at both the vertical and horizontal meridians. We propose that this finding is the behavioral consequence of the anatomical gaps at both meridians, suggesting that neural areas with quadrantic representations (e.g., V2, V3) are the initial locus of this motion-induced position shift. This result rules out V1 as the source of the illusion because it has an anatomical break only at the vertical meridian.
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Affiliation(s)
- Sirui Liu
- Department of Psychological and Brian Sciences, Dartmouth College , Hanover, New Hampshire
| | - Peter U Tse
- Department of Psychological and Brian Sciences, Dartmouth College , Hanover, New Hampshire
| | - Patrick Cavanagh
- Department of Psychological and Brian Sciences, Dartmouth College , Hanover, New Hampshire.,Department of Psychology, Glendon College , Toronto, Ontario , Canada
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Strother L, Zhou Z, Coros AK, Vilis T. An fMRI study of visual hemifield integration and cerebral lateralization. Neuropsychologia 2017; 100:35-43. [PMID: 28396097 DOI: 10.1016/j.neuropsychologia.2017.04.003] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Revised: 03/27/2017] [Accepted: 04/02/2017] [Indexed: 11/19/2022]
Abstract
The human brain integrates hemifield-split visual information via interhemispheric transfer. The degree to which neural circuits involved in this process behave differently during word recognition as compared to object recognition is not known. Evidence from neuroimaging (fMRI) suggests that interhemispheric transfer during word viewing converges in the left hemisphere, in two distinct brain areas, an "occipital word form area" (OWFA) and a more anterior occipitotemporal "visual word form area" (VWFA). We used a novel fMRI half-field repetition technique to test whether or not these areas also integrate nonverbal hemifield-split string stimuli of similar visual complexity. We found that the fMRI responses of both the OWFA and VWFA while viewing nonverbal stimuli were strikingly different than those measured during word viewing, especially with respect to half-stimulus changes restricted to a single hemifield. We conclude that normal reading relies on left-lateralized neural mechanisms, which integrate hemifield-split visual information for words but not for nonverbal stimuli.
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Affiliation(s)
- Lars Strother
- University of Nevada, Reno, Department of Psychology, USA.
| | - Zhiheng Zhou
- University of Nevada, Reno, Department of Psychology, USA
| | | | - Tutis Vilis
- University of Western Ontario, Brain and Mind Institute, Canada
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Cao HW, Yang KF, Yan HM. Character Decomposition and Transposition of Chinese Compound Words in the Right and Left Visual Fields. Iperception 2016; 7:2041669516675366. [PMID: 27847584 PMCID: PMC5098684 DOI: 10.1177/2041669516675366] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
This study investigated the character decomposition and transposition processes of Chinese two-character compound words (canonical and transposed words) and pseudowords in the right and left visual fields using a dual-target rapid serial visual presentation paradigm. The results confirmed a right visual field superiority for canonical words, but this advantage vanished for transposed words. The findings further indicated that the same quality of lexical processing could be obtained from the foveal and parafoveal regions of the right and left visual fields, regardless of the character order, but not in the periphery of the right visual field. Moreover, the proportion of order reversals peaked at the central position and the shortest exposure time, but it declined with increasing eccentricity and time interval. We concluded that the character transposition of Chinese compound words was significantly sensitive in the periphery of the right visual field. Furthermore, the character order errors were mainly encoded in the foveal vision with a duration of 100 ms, which suggested that the order of the foveally presented Chinese characters was more likely to be reversed at the early stage of visual word processing.
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Affiliation(s)
- Hong-Wen Cao
- Key Laboratory for Neuroinformation of Ministry of Education, University of Electronic Science and Technology of China, Chengdu, China
| | - Kai-Fu Yang
- Key Laboratory for Neuroinformation of Ministry of Education, University of Electronic Science and Technology of China, Chengdu, China
| | - Hong-Mei Yan
- Key Laboratory for Neuroinformation of Ministry of Education, University of Electronic Science and Technology of China, Chengdu, China; Center for Information in Biomedicine, University of Electronic Science and Technology of China, Chengdu, China
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Reinhart RMG, Xiao W, McClenahan LJ, Woodman GF. Electrical Stimulation of Visual Cortex Can Immediately Improve Spatial Vision. Curr Biol 2016; 26:1867-72. [PMID: 27374337 DOI: 10.1016/j.cub.2016.05.019] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2015] [Revised: 04/15/2016] [Accepted: 05/05/2016] [Indexed: 01/10/2023]
Abstract
We can improve human vision by correcting the optics of our lenses [1-3]. However, after the eye transduces the light, visual cortex has its own limitations that are challenging to correct [4]. Overcoming these limitations has typically involved innovative training regimes that improve vision across many days [5, 6]. In the present study, we wanted to determine whether it is possible to immediately improve the precision of spatial vision with noninvasive direct-current stimulation. Previous work suggested that visual processing could be modulated with such stimulation [7-9]. However, the short duration and variability of such effects made it seem unlikely that spatial vision could be improved for more than several minutes [7, 10]. Here we show that visual acuity in the parafoveal belt can be immediately improved by delivering noninvasive direct current to visual cortex. Twenty minutes of anodal stimulation improved subjects' vernier acuity by approximately 15% and increased the amplitude of the earliest visually evoked potentials in lockstep with the behavioral effects. When we reversed the orientation of the electric field, we impaired resolution and reduced the amplitude of visually evoked potentials. Next, we found that anodal stimulation improved acuity enough to be measurable with the relatively coarse Snellen test and that subjects with the poorest acuity benefited the most from stimulation. Finally, we found that stimulation-induced acuity improvements were accompanied by changes in contrast sensitivity at high spatial frequencies.
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Affiliation(s)
- Robert M G Reinhart
- Department of Psychological and Brain Sciences, Boston University, Boston, MA 02215, USA
| | - Wenxi Xiao
- Department of Psychology, Center for Integrative and Cognitive Neuroscience, Vanderbilt Vision Research Center, Vanderbilt University, Nashville, TN 37240, USA
| | - Laura J McClenahan
- Department of Psychology, Center for Integrative and Cognitive Neuroscience, Vanderbilt Vision Research Center, Vanderbilt University, Nashville, TN 37240, USA
| | - Geoffrey F Woodman
- Department of Psychology, Center for Integrative and Cognitive Neuroscience, Vanderbilt Vision Research Center, Vanderbilt University, Nashville, TN 37240, USA.
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17
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Binelli C, Muñiz A, Subira S, Navines R, Blanco-Hinojo L, Perez-Garcia D, Crippa J, Farré M, Pérez-Jurado L, Pujol J, Martin-Santos R. Facial emotion processing in patients with social anxiety disorder and Williams-Beuren syndrome: an fMRI study. J Psychiatry Neurosci 2016; 41:182-91. [PMID: 26624523 PMCID: PMC4853209 DOI: 10.1503/jpn.140384] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
BACKGROUND Social anxiety disorder (SAD) and Williams-Beuren syndrome (WBS) are 2 conditions with major differences in terms of genetics, development and cognitive profiles. Both conditions are associated with compromised abilities in overlapping areas, including social approach, processing of social emotional cues and gaze behaviour, and to some extent they are associated with opposite behaviours in these domains. We examined common and distinct patterns of brain activation during a facial emotion processing paradigm in patients with SAD and WBS. METHODS We examined patients with SAD and WBS and healthy controls matched by age and laterality using functional MRI during the processing of happy, fearful and angry faces. RESULTS We included 20 patients with SAD and 20 with WBS as well as 20 matched controls in our study. Patients with SAD and WBS did not differ in the pattern of limbic activation. We observed differences in early visual areas of the face processing network in patients with WBS and differences in the cortical prefrontal regions involved in the top-down regulation of anxiety and in the fusiform gyrus for patients with SAD. Compared with those in the SAD and control groups, participants in the WBS group did not activate the right lateral inferior occipital cortex. In addition, compared with controls, patients with WBS hypoactivated the posterior primary visual cortex and showed significantly less deactivation in the right temporal operculum. Participants in the SAD group showed decreased prefrontal activation compared with those in the WBS and control groups. In addition, compared with controls, participants with SAD showed decreased fusiform activation. Participants with SAD and WBS also differed in the pattern of activation in the superior temporal gyrus, a region that has been linked to gaze processing. LIMITATIONS The results observed in the WBS group are limited by the IQ of the WBS sample; however, the specificity of findings suggests that the pattern of brain activation observed for WBS is more likely to reflect a neurobiological substrate rather than intellectual impairment per se. CONCLUSION Patients with SAD and WBS showed common and specific patterns of brain activation. Our results highlight the role of cortical regions during facial emotion processing in individuals with SAD and WBS.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | - Rocio Martin-Santos
- Correspondence to: R. Martin-Santos, Department of Psychiatry and Psychology, Hospital Clínic, Institut d’Investigacions Biomèdicas August Pi I Sunyer (IDIBAPS), Centro de Investigación Biomédica en Red en Salud Mental (CIBERSAM), Villarroel, 170, 08036-Barcelona, Spain;
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18
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Strother L, Coros AM, Vilis T. Visual Cortical Representation of Whole Words and Hemifield-split Word Parts. J Cogn Neurosci 2016; 28:252-60. [DOI: 10.1162/jocn_a_00900] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Abstract
Reading requires the neural integration of visual word form information that is split between our retinal hemifields. We examined multiple visual cortical areas involved in this process by measuring fMRI responses while observers viewed words that changed or repeated in one or both hemifields. We were specifically interested in identifying brain areas that exhibit decreased fMRI responses as a result of repeated versus changing visual word form information in each visual hemifield. Our method yielded highly significant effects of word repetition in a previously reported visual word form area (VWFA) in occipitotemporal cortex, which represents hemifield-split words as whole units. We also identified a more posterior occipital word form area (OWFA), which represents word form information in the right and left hemifields independently and is thus both functionally and anatomically distinct from the VWFA. Both the VWFA and the OWFA were left-lateralized in our study and strikingly symmetric in anatomical location relative to known face-selective visual cortical areas in the right hemisphere. Our findings are consistent with the observation that category-selective visual areas come in pairs and support the view that neural mechanisms in left visual cortex—especially those that evolved to support the visual processing of faces—are developmentally malleable and become incorporated into a left-lateralized visual word form network that supports rapid word recognition and reading.
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Affiliation(s)
- Lars Strother
- 1University of Western Ontario
- 2University of Nevada, Reno
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19
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Cross-hemispheric collaboration and segregation associated with task difficulty as revealed by structural and functional connectivity. J Neurosci 2015; 35:8191-200. [PMID: 26019335 DOI: 10.1523/jneurosci.0464-15.2015] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Although it is known that brain regions in one hemisphere may interact very closely with their corresponding contralateral regions (collaboration) or operate relatively independent of them (segregation), the specific brain regions (where) and conditions (how) associated with collaboration or segregation are largely unknown. We investigated these issues using a split field-matching task in which participants matched the meaning of words or the visual features of faces presented to the same (unilateral) or to different (bilateral) visual fields. Matching difficulty was manipulated by varying the semantic similarity of words or the visual similarity of faces. We assessed the white matter using the fractional anisotropy (FA) measure provided by diffusion tensor imaging (DTI) and cross-hemispheric communication in terms of fMRI-based connectivity between homotopic pairs of cortical regions. For both perceptual and semantic matching, bilateral trials became faster than unilateral trials as difficulty increased (bilateral processing advantage, BPA). The study yielded three novel findings. First, whereas FA in anterior corpus callosum (genu) correlated with word-matching BPA, FA in posterior corpus callosum (splenium-occipital) correlated with face-matching BPA. Second, as matching difficulty intensified, cross-hemispheric functional connectivity (CFC) increased in domain-general frontopolar cortex (for both word and face matching) but decreased in domain-specific ventral temporal lobe regions (temporal pole for word matching and fusiform gyrus for face matching). Last, a mediation analysis linking DTI and fMRI data showed that CFC mediated the effect of callosal FA on BPA. These findings clarify the mechanisms by which the hemispheres interact to perform complex cognitive tasks.
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20
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Yang T, Zhang J, Bao Y. Spatial orienting around the fovea: exogenous and endogenous cueing effects. Cogn Process 2015; 16 Suppl 1:137-41. [PMID: 26232192 DOI: 10.1007/s10339-015-0688-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
The effect of covert attention in perifoveal and peripheral locations has been studied extensively. However, it is less clear whether attention operates similarly in the foveal area itself. The present study aims to investigate whether the attentional orienting elicited by an exogenous or endogenous cue can operate within the foveal area and whether attentional orienting operates similarly between foveal and perifoveal regions. By manipulating exogenous orienting in Experiment 1 and endogenous orienting in Experiment 2, we observed both forms of cueing in the foveal area. Specifically, we observed a larger exogenous cue-induced inhibitory effect (i.e., inhibition of return effect) and a similar endogenous cue-elicited facilitatory effect for the perifoveal relative to the foveal targets. We conclude that exogenous and endogenous orienting subject to two independent attentional systems with distinct modulation patterns in the foveal area.
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Affiliation(s)
- Taoxi Yang
- Institute of Medical Psychology, Ludwig Maximilian University, Munich, Germany
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21
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Helfrich RF, Knepper H, Nolte G, Strüber D, Rach S, Herrmann CS, Schneider TR, Engel AK. Selective modulation of interhemispheric functional connectivity by HD-tACS shapes perception. PLoS Biol 2014; 12:e1002031. [PMID: 25549264 PMCID: PMC4280108 DOI: 10.1371/journal.pbio.1002031] [Citation(s) in RCA: 193] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2014] [Accepted: 11/17/2014] [Indexed: 11/18/2022] Open
Abstract
Oscillatory neuronal synchronization between cortical areas has been suggested to constitute a flexible mechanism to coordinate information flow in the human cerebral cortex. However, it remains unclear whether synchronized neuronal activity merely represents an epiphenomenon or whether it is causally involved in the selective gating of information. Here, we combined bilateral high-density transcranial alternating current stimulation (HD-tACS) at 40 Hz with simultaneous electroencephalographic (EEG) recordings to study immediate electrophysiological effects during the selective entrainment of oscillatory gamma-band signatures. We found that interhemispheric functional connectivity was modulated in a predictable, phase-specific way: In-phase stimulation enhanced synchronization, anti-phase stimulation impaired functional coupling. Perceptual correlates of these connectivity changes were found in an ambiguous motion task, which strongly support the functional relevance of long-range neuronal coupling. Additionally, our results revealed a decrease in oscillatory alpha power in response to the entrainment of gamma band signatures. This finding provides causal evidence for the antagonistic role of alpha and gamma oscillations in the parieto-occipital cortex and confirms that the observed gamma band modulations were physiological in nature. Our results demonstrate that synchronized cortical network activity across several spatiotemporal scales is essential for conscious perception and cognition.
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Affiliation(s)
- Randolph F Helfrich
- Department of Neurophysiology and Pathophysiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Hannah Knepper
- Department of Neurophysiology and Pathophysiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Guido Nolte
- Department of Neurophysiology and Pathophysiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Daniel Strüber
- Experimental Psychology Lab, Center for Excellence 'Hearing4all', European Medical School, University of Oldenburg, Oldenburg, Germany; Research Center Neurosensory Science, University of Oldenburg, Oldenburg, Germany
| | - Stefan Rach
- Experimental Psychology Lab, Center for Excellence 'Hearing4all', European Medical School, University of Oldenburg, Oldenburg, Germany; Research Center Neurosensory Science, University of Oldenburg, Oldenburg, Germany; Department of Epidemiological Methods and Etiologic Research, Leibniz Institute for Prevention Research and Epidemiology - BIPS, Bremen, Germany
| | - Christoph S Herrmann
- Experimental Psychology Lab, Center for Excellence 'Hearing4all', European Medical School, University of Oldenburg, Oldenburg, Germany; Research Center Neurosensory Science, University of Oldenburg, Oldenburg, Germany
| | - Till R Schneider
- Department of Neurophysiology and Pathophysiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Andreas K Engel
- Department of Neurophysiology and Pathophysiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
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22
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Akin B, Ozdem C, Eroglu S, Keskin DT, Fang F, Doerschner K, Kersten D, Boyaci H. Attention modulates neuronal correlates of interhemispheric integration and global motion perception. J Vis 2014; 14:14.12.30. [PMID: 25349270 DOI: 10.1167/14.12.30] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
In early retinotopic areas of the human visual system, information from the left and right visual hemifields (VHFs) is processed contralaterally in two hemispheres. Despite this segregation, we have the perceptual experience of a unified, coherent, and uninterrupted single visual field. How exactly the visual system integrates information from the two VHFs and achieves this perceptual experience still remains largely unknown. In this study using fMRI, we explored candidate areas that are involved in interhemispheric integration and the perceptual experience of a unified, global motion across VHFs. Stimuli were two-dimensional, computer-generated objects with parts in both VHFs. The retinal image in the left VHF always remained stationary, but in the experimental condition, it appeared to have local motion because of the perceived global motion of the object. This perceptual effect could be weakened by directing the attention away from the global motion through a demanding fixation task. Results show that lateral occipital areas, including the medial temporal complex, play an important role in the process of perceptual experience of a unified global motion across VHFs. In early areas, including the lateral geniculate nucleus and V1, we observed correlates of this perceptual experience only when attention is not directed away from the object. These findings reveal effects of attention on interhemispheric integration in motion perception and imply that both the bilateral activity of higher-tier visual areas and feedback mechanisms leading to bilateral activity of early areas play roles in the perceptual experience of a unified visual field.
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Affiliation(s)
- Burak Akin
- Department of Radiology, Medical Physics, University Medical Center Freiburg, Germany
| | | | | | | | - Fang Fang
- Department of Psychology and Key Laboratory of Machine Perception (Ministry of Education), Peking University, Beijing, China Peking-Tsinghua Center for Life Sciences, Beijing, China PKU-IDG/McGovern Institute for Brain Research, Peking University, Beijing, China
| | - Katja Doerschner
- Department of Psychology & National Magnetic Resonance Research Center, Bilkent University, Ankara, Turkey
| | - Daniel Kersten
- Department of Psychology, University of Minnesota, Minneapolis, MN
| | - Huseyin Boyaci
- Department of Psychology & National Magnetic Resonance Research Center, Bilkent University, Ankara, Turkey
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23
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Jordan TR, Sheen M, Abedipour L, Paterson KB. Visual speech perception in foveal and extrafoveal vision: further implications for divisions in hemispheric projections. PLoS One 2014; 9:e98273. [PMID: 25032950 PMCID: PMC4102446 DOI: 10.1371/journal.pone.0098273] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2014] [Accepted: 04/30/2014] [Indexed: 11/19/2022] Open
Abstract
When observing a talking face, it has often been argued that visual speech to the left and right of fixation may produce differences in performance due to divided projections to the two cerebral hemispheres. However, while it seems likely that such a division in hemispheric projections exists for areas away from fixation, the nature and existence of a functional division in visual speech perception at the foveal midline remains to be determined. We investigated this issue by presenting visual speech in matched hemiface displays to the left and right of a central fixation point, either exactly abutting the foveal midline or else located away from the midline in extrafoveal vision. The location of displays relative to the foveal midline was controlled precisely using an automated, gaze-contingent eye-tracking procedure. Visual speech perception showed a clear right hemifield advantage when presented in extrafoveal locations but no hemifield advantage (left or right) when presented abutting the foveal midline. Thus, while visual speech observed in extrafoveal vision appears to benefit from unilateral projections to left-hemisphere processes, no evidence was obtained to indicate that a functional division exists when visual speech is observed around the point of fixation. Implications of these findings for understanding visual speech perception and the nature of functional divisions in hemispheric projection are discussed.
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Affiliation(s)
| | | | - Lily Abedipour
- School of Psychology, University of Leicester, Leicester, United Kingdom
| | - Kevin B. Paterson
- School of Psychology, University of Leicester, Leicester, United Kingdom
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24
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Koenraads Y, van der Linden DCP, van Schooneveld MMJ, Imhof SM, Gosselaar PH, Porro GL, Braun KPJ. Visual function and compensatory mechanisms for hemianopia after hemispherectomy in children. Epilepsia 2014; 55:909-17. [PMID: 24754334 DOI: 10.1111/epi.12615] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/02/2014] [Indexed: 11/30/2022]
Affiliation(s)
- Yvonne Koenraads
- Department of Ophthalmology; University Medical Center Utrecht; Utrecht The Netherlands
| | | | - Monique M. J. van Schooneveld
- Department of Pediatric Psychology; Sector Neuropsychology; University Medical Center Utrecht; Utrecht The Netherlands
| | - Saskia M. Imhof
- Department of Ophthalmology; University Medical Center Utrecht; Utrecht The Netherlands
| | - P. H. Gosselaar
- Department of Neurosurgery; Brain Center Rudolf Magnus; University Medical Center Utrecht; Utrecht The Netherlands
| | - Giorgio L. Porro
- Department of Ophthalmology; University Medical Center Utrecht; Utrecht The Netherlands
| | - Kees P. J. Braun
- Department of Pediatric Neurology; Brain Center Rudolf Magnus; University Medical Center Utrecht; Utrecht The Netherlands
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25
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Forgács B, Lukács A, Pléh C. Lateralized processing of novel metaphors: disentangling figurativeness and novelty. Neuropsychologia 2014; 56:101-9. [PMID: 24418155 DOI: 10.1016/j.neuropsychologia.2014.01.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2012] [Revised: 10/09/2013] [Accepted: 01/04/2014] [Indexed: 10/25/2022]
Abstract
One of the intriguing and sometimes controversial findings in figurative language research is a right-hemisphere processing advantage for novel metaphors. The current divided visual field study introduced novel literal expressions as a control condition to assess processing novelty independent of figurativeness. Participants evaluated word pairs belonging to one of the five categories: (1) conventional metaphorical, (2) conventional literal, (3) novel metaphorical, (4) novel literal, and (5) unrelated expressions in a semantic decision task. We presented expressions without sentence context and controlled for additional factors including emotional valence, arousal, and imageability that could potentially influence hemispheric processing. We also utilized an eye-tracker to ensure lateralized presentation. We did not find the previously reported right-hemispherical processing advantage for novel metaphors. Processing was faster in the left hemisphere for all types of word pairs, and accuracy was also higher in the right visual field - left hemisphere. Novel metaphors were processed just as fast as novel literal expressions, suggesting that the primary challenge during the comprehension of novel expressions is not a serial processing of salience, but perhaps a more left hemisphere weighted semantic integration. Our results cast doubt on the right-hemisphere theory of metaphors, and raise the possibility that other uncontrolled variables were responsible for previous results. The lateralization of processing of two word expressions seems to be more contingent on the specific task at hand than their figurativeness or saliency.
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Affiliation(s)
- Bálint Forgács
- Budapest University of Technology and Economics (BME), Department of Cognitive Science, Egry József utca 1, T building, V. 506, 1111 Budapest, Hungary; Central European University (CEU), Department of Cognitive Science, Frankel Leó út 30-34, 1023 Budapest, Hungary.
| | - Agnes Lukács
- Budapest University of Technology and Economics (BME), Department of Cognitive Science, Egry József utca 1, T building, V. 506, 1111 Budapest, Hungary.
| | - Csaba Pléh
- Budapest University of Technology and Economics (BME), Department of Cognitive Science, Egry József utca 1, T building, V. 506, 1111 Budapest, Hungary; Eszterházy Károly College, Doctoral School of Education, Eszterházy tér 1, 3300 Eger, Hungary.
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26
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Larsson M. The optic chiasm: a turning point in the evolution of eye/hand coordination. Front Zool 2013; 10:41. [PMID: 23866932 PMCID: PMC3729728 DOI: 10.1186/1742-9994-10-41] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2013] [Accepted: 07/09/2013] [Indexed: 01/23/2023] Open
Abstract
The primate visual system has a uniquely high proportion of ipsilateral retinal projections, retinal ganglial cells that do not cross the midline in the optic chiasm. The general assumption is that this developed due to the selective advantage of accurate depth perception through stereopsis. Here, the hypothesis that the need for accurate eye-forelimb coordination substantially influenced the evolution of the primate visual system is presented. Evolutionary processes may change the direction of retinal ganglial cells. Crossing, or non-crossing, in the optic chiasm determines which hemisphere receives visual feedback in reaching tasks. Each hemisphere receives little tactile and proprioceptive information about the ipsilateral hand. The eye-forelimb hypothesis proposes that abundant ipsilateral retinal projections developed in the primate brain to synthesize, in a single hemisphere, visual, tactile, proprioceptive, and motor information about a given hand, and that this improved eye-hand coordination and optimized the size of the brain. If accurate eye-hand coordination was a major factor in the evolution of stereopsis, stereopsis is likely to be highly developed for activity in the area where the hands most often operate.The primate visual system is ideally suited for tasks within arm's length and in the inferior visual field, where most manual activity takes place. Altering of ocular dominance in reaching tasks, reduced cross-modal cuing effects when arms are crossed, response of neurons in the primary motor cortex to viewed actions of a hand, multimodal neuron response to tactile as well as visual events, and extensive use of multimodal sensory information in reaching maneuvers support the premise that benefits of accurate limb control influenced the evolution of the primate visual system. The eye-forelimb hypothesis implies that evolutionary change toward hemidecussation in the optic chiasm provided parsimonious neural pathways in animals developing frontal vision and visually guided forelimbs, and also suggests a new perspective on vision convergence in prey and predatory animals.
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Affiliation(s)
- Matz Larsson
- The Cardiology Clinic, Örebro University Hospital, SE - 701 85, Örebro, Sweden.
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27
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Van der Haegen L, Cai Q, Stevens MA, Brysbaert M. Interhemispheric communication influences reading behavior. J Cogn Neurosci 2013; 25:1442-52. [PMID: 23647517 DOI: 10.1162/jocn_a_00412] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
We can read words at an amazing speed, with the left hemisphere taking the burden of the processing in most readers (i.e., over 95% of right-handers and about 75% of left-handers). Yet, it is a long-standing question whether word reading in central vision is possible without information transfer between the left and right hemispheres (LH/RH). Here we show that such communication is required by comparing word naming latencies and eye movement data of people with LH language dominance and a unique sample of healthy RH dominant people. The results reveal that individuals with LH speech dominance name words faster when they are allowed to fixate at the word beginning, whereas RH dominants are faster for fixations toward the end. In text reading, the eyes of LH dominants land more to the left than the eyes of RH dominants, making more information directly available to the dominant hemisphere. We conclude that the traditional view of bilateral projections in central vision is incorrect. In contrast, interhemispheric communication is needed in central vision, and eye movements are adjusted to optimize information uptake. Our findings therefore call into question the explanation of macular sparing in hemianopia based on a bilaterally projecting fovea. In addition, these results are in line with the increase of white matter in the splenium of the corpus callosum when people learn to read.
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28
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Hsiao JH, Lam SM. The Modulation of Visual and Task Characteristics of a Writing System on Hemispheric Lateralization in Visual Word Recognition-A Computational Exploration. Cogn Sci 2013; 37:861-90. [DOI: 10.1111/cogs.12033] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2012] [Revised: 06/19/2012] [Accepted: 08/23/2012] [Indexed: 11/28/2022]
Affiliation(s)
| | - Sze Man Lam
- Department of Psychology; University of Hong Kong
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29
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Ducrot S, Pynte J, Ghio A, Lété B. Visual and linguistic determinants of the eyes' initial fixation position in reading development. Acta Psychol (Amst) 2013; 142:287-98. [PMID: 23419806 DOI: 10.1016/j.actpsy.2013.01.013] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2012] [Revised: 12/13/2012] [Accepted: 01/18/2013] [Indexed: 11/27/2022] Open
Abstract
Two eye-movement experiments with one hundred and seven first- through fifth-grade children were conducted to examine the effects of visuomotor and linguistic factors on the recognition of words and pseudowords presented in central vision (using a variable-viewing-position technique) and in parafoveal vision (shifted to the left or right of a central fixation point). For all groups of children, we found a strong effect of stimulus location, in both central and parafoveal vision. This effect corresponds to the children's apparent tendency, for peripherally located targets, to reach a position located halfway between the middle and the left edge of the stimulus (preferred viewing location, PVL), whether saccading to the right or left. For centrally presented targets, refixation probability and lexical-decision time were the lowest near the word's center, suggesting an optimal viewing position (OVP). The viewing-position effects found here were modulated (1) by print exposure, both in central and parafoveal vision; and (2) by the intrinsic qualities of the stimulus (lexicality and word frequency) for targets in central vision but not for parafoveally presented targets.
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30
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Hsiao JH, Cheng L. The modulation of stimulus structure on visual field asymmetry effects: the case of Chinese character recognition. Q J Exp Psychol (Hove) 2013; 66:1739-55. [PMID: 23391072 DOI: 10.1080/17470218.2013.764902] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Recent research suggests that visual field (VF) asymmetry effects in visual recognition may be influenced by information distribution within the stimuli for the recognition task in addition to hemispheric processing differences: Stimuli with more information on the left have a right VF (RVF) advantage because the left part is closer to the centre, where the highest visual acuity is obtained. It remains unclear whether visual complexity distribution of the stimuli also has similar modulation effects. Here we used Chinese characters with contrasting structures-left-heavy, symmetric, and right-heavy, in terms of either visual complexity of components or information distribution defined by location of the phonetic component-and examined participants' naming performance. We found that left-heavy characters had the largest RVF advantage, followed by symmetric and right-heavy characters; this effect was only observed in characters that contrasted in information distribution, in which information for pronunciation was skewed to the phonetic component, but not in those that contrasted only in visual complexity distribution and had no phonetic component. This result provides strong evidence for the influence of information distribution within the stimuli on VF asymmetry effects; in contrast, visual complexity distribution within the stimuli does not have similar modulation effects.
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Affiliation(s)
- Janet H Hsiao
- a Department of Psychology , University of Hong Kong , Hong Kong
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31
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The ventral visual pathway: an expanded neural framework for the processing of object quality. Trends Cogn Sci 2012; 17:26-49. [PMID: 23265839 DOI: 10.1016/j.tics.2012.10.011] [Citation(s) in RCA: 670] [Impact Index Per Article: 55.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2012] [Revised: 10/24/2012] [Accepted: 10/29/2012] [Indexed: 01/01/2023]
Abstract
Since the original characterization of the ventral visual pathway, our knowledge of its neuroanatomy, functional properties, and extrinsic targets has grown considerably. Here we synthesize this recent evidence and propose that the ventral pathway is best understood as a recurrent occipitotemporal network containing neural representations of object quality both utilized and constrained by at least six distinct cortical and subcortical systems. Each system serves its own specialized behavioral, cognitive, or affective function, collectively providing the raison d'être for the ventral visual pathway. This expanded framework contrasts with the depiction of the ventral visual pathway as a largely serial staged hierarchy culminating in singular object representations and more parsimoniously incorporates attentional, contextual, and feedback effects.
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32
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Woodhead ZVJ, Barnes GR, Penny W, Moran R, Teki S, Price CJ, Leff AP. Reading front to back: MEG evidence for early feedback effects during word recognition. Cereb Cortex 2012; 24:817-25. [PMID: 23172772 PMCID: PMC3920772 DOI: 10.1093/cercor/bhs365] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Magnetoencephalography studies in humans have shown word-selective activity in the left inferior frontal gyrus (IFG) approximately 130 ms after word presentation (
Pammer et al. 2004; Cornelissen et al. 2009; Wheat et al. 2010). The role of this early frontal response is currently not known. We tested the hypothesis that the IFG provides top-down constraints on word recognition using dynamic causal modeling of magnetoencephalography data collected, while subjects viewed written words and false font stimuli. Subject-specific dipoles in left and right occipital, ventral occipitotemporal and frontal cortices were identified using Variational Bayesian Equivalent Current Dipole source reconstruction. A connectivity analysis tested how words and false font stimuli differentially modulated activity between these regions within the first 300 ms after stimulus presentation. We found that left inferior frontal activity showed stronger sensitivity to words than false font and a stronger feedback connection onto the left ventral occipitotemporal cortex (vOT) in the first 200 ms. Subsequently, the effect of words relative to false font was observed on feedforward connections from left occipital to ventral occipitotemporal and frontal regions. These findings demonstrate that left inferior frontal activity modulates vOT in the early stages of word processing and provides a mechanistic account of top-down effects during word recognition.
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Affiliation(s)
- Z V J Woodhead
- Wellcome Trust Centre for Neuroimaging, University College London, London, UK
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33
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Cowey A, Alexander I, Ellison A. Modulation of cortical excitability can speed up blindsight but not improve it. Exp Brain Res 2012; 224:469-75. [PMID: 23229773 DOI: 10.1007/s00221-012-3327-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2012] [Accepted: 10/26/2012] [Indexed: 11/28/2022]
Abstract
Blindsight has been widely investigated and its properties documented. One property still debated and contested is the puzzling absence of phenomenal visual percepts of visual stimuli that can be detected with perfect accuracy. We investigated the possibility that phenomenal visual percepts of exogenous visual stimuli in patient GY might be induced by using transcranial direct current stimulation. High contrast and low contrast stimuli were presented as a moving grating in his blind hemifield. When left area MT/V5 was anodally stimulated during the presentation of high-contrast gratings, he never reported a phenomenal percept of a moving grating but showed perfect blindsight performance. When applied along with low contrast gratings, for which accuracy was titrated to 60-70 %, performance did not improve but responses were significantly faster. Cathodal stimulation had no effect. Results are explained in the framework of GY's reorganized cortical connexions and oscillatory patterns known to be involved in awareness in GY. The apparent presence of phenomenal visual percepts in earlier studies is shown to be a semantic confusion about what he means when he says that he sees in his blind field.
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Affiliation(s)
- Alan Cowey
- Department of Experimental Psychology, Oxford University, South Parks Road, Oxford OX1 3UD, UK
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34
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Obregón M, Shillcock R. Foveational complexity in single word identification: contralateral visual pathways are advantaged over ipsilateral pathways. Neuropsychologia 2012; 50:3279-83. [PMID: 22982485 DOI: 10.1016/j.neuropsychologia.2012.09.009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2012] [Revised: 07/31/2012] [Accepted: 09/04/2012] [Indexed: 11/15/2022]
Abstract
Recognition of a single word is an elemental task in innumerable cognitive psychology experiments, but involves unexpected complexity. We test a controversial claim that the human fovea is vertically divided, with each half projecting to either the contralateral or ipsilateral hemisphere, thereby influencing foveal word recognition. We report a novel haploscope task: the two halves of a four-letter word were briefly presented to the two eyes in a Both condition (st|ep)(st|ep), a Contralateral condition (st|__)(__|ep), or an Ipsilateral condition (__|ep)(st|__), all yielding the same single word percept (step). The Both condition yielded superior perceptual recognition, followed by the contralateral projection, then the ipsilateral projection. These results demonstrate that the structure of the fovea influences even the recognition of short, foveally presented words. Projecting different parts of the same word to different hemispheres involves unforeseen complexities and opportunities for optimizing hemispheric coordination.
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Affiliation(s)
- Mateo Obregón
- School of Philosophy, Psychology, and Language Sciences, University of Edinburgh, 7 George Square, Edinburgh EH8 9JZ, UK.
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Rutherford BJ, Mathesius JR. The brain's hemispheres and controlled search of the lexicon: evidence from fixated words and pseudowords. Brain Cogn 2012; 79:188-99. [PMID: 22542843 DOI: 10.1016/j.bandc.2012.03.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2010] [Revised: 11/06/2011] [Accepted: 03/01/2012] [Indexed: 10/28/2022]
Abstract
Difference between the brain's hemispheres in efficiency of intentional search of the mental lexicon with phonological, orthographic, and semantic strategies was investigated. Letter strings for lexical decision were presented at fixation, with a lateralized distractor to the LVF or RVF. Word results revealed that both hemispheres were capable of using each of the three strategies, but the right hemisphere had better baseline processing of orthography and was better at processing semantics. Pseudoword results supported the right hemisphere advantage for orthography and showed a left hemisphere advantage for phonology and assessment of possible semantic relationships. Taken together, the data support the idea that the right hemisphere uses orthography to make efficient decisions about novelty of an item, while the left engages in grapheme-to-phoneme conversion to test hypotheses about unfamiliar items. The convergence of data with previous research reveals that the procedure, as well as analyses of pseudowords, inform laterality research.
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Affiliation(s)
- Barbara J Rutherford
- Psychology Department, University of British Columbia, Okanagan, Kelowna, British Columbia, Canada.
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Zurawska Vel Grajewska B, Sim EJ, Hoenig K, Herrnberger B, Kiefer M. Mechanisms underlying flexible adaptation of cognitive control: behavioral and neuroimaging evidence in a flanker task. Brain Res 2011; 1421:52-65. [PMID: 21981803 DOI: 10.1016/j.brainres.2011.09.022] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2011] [Accepted: 09/10/2011] [Indexed: 10/17/2022]
Abstract
Cognitive control can be adapted flexibly according to the conflict level in a given situation. In the Eriksen flanker task, interference evoked by flankers is larger in conditions with a higher, rather than a lower proportion of compatible trials. Such compatibility ratio effects also occur for stimuli presented at two spatial locations suggesting that different cognitive control settings can be simultaneously maintained. However, the conditions and the neural correlates of this flexible adaptation of cognitive control are only poorly understood. In the present study, we further elucidated the mechanisms underlying the simultaneous maintenance of two cognitive control settings. In behavioral experiments, stimuli were presented centrally above and below fixation and hence processed by both hemispheres or lateralized to stimulate hemispheres differentially. The different compatibility ratio at two stimulus locations had a differential influence on the flanker effect in both experiments. In an fMRI experiment, blocks with an identical compatibility ratio at two central spatial locations elicited stronger activity in a network of prefrontal and parietal brain areas, which are known to be involved in conflict resolution and cognitive control, as compared with blocks with a different compatibility ratio at the same spatial locations. This demonstrates that the simultaneous maintenance of two conflicting control settings vs. one single setting does not recruit additional neural circuits suggesting the involvement of one single cognitive control system. Instead a crosstalk between multiple control settings renders adaptation of cognitive control more efficient when only one uniform rather than two different control settings has to be simultaneously maintained.
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Jordan TR, Fuggetta G, Paterson KB, Kurtev S, Xu M. An ERP assessment of hemispheric projections in foveal and extrafoveal word recognition. PLoS One 2011; 6:e23957. [PMID: 21935368 PMCID: PMC3174137 DOI: 10.1371/journal.pone.0023957] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2011] [Accepted: 08/02/2011] [Indexed: 11/19/2022] Open
Abstract
Background The existence and function of unilateral hemispheric projections within foveal vision may substantially affect foveal word recognition. The purpose of this research was to reveal these projections and determine their functionality. Methodology Single words (and pseudowords) were presented to the left or right of fixation, entirely within either foveal or extrafoveal vision. To maximize the likelihood of unilateral projections for foveal displays, stimuli in foveal vision were presented away from the midline. The processing of stimuli in each location was assessed by combining behavioural measures (reaction times, accuracy) with on-line monitoring of hemispheric activity using event-related potentials recorded over each hemisphere, and carefully-controlled presentation procedures using an eye-tracker linked to a fixation-contingent display. Principal Findings Event-related potentials 100–150 ms and 150–200 ms after stimulus onset indicated that stimuli in extrafoveal and foveal locations were projected unilaterally to the hemisphere contralateral to the presentation hemifield with no concurrent projection to the ipsilateral hemisphere. These effects were similar for words and pseudowords, suggesting this early division occurred before word recognition. Indeed, event-related potentials revealed differences between words and pseudowords 300–350 ms after stimulus onset, for foveal and extrafoveal locations, indicating that word recognition had now occurred. However, these later event-related potentials also revealed that the hemispheric division observed previously was no longer present for foveal locations but remained for extrafoveal locations. These findings closely matched the behavioural finding that foveal locations produced similar performance each side of fixation but extrafoveal locations produced left-right asymmetries. Conclusions These findings indicate that an initial division in unilateral hemispheric projections occurs in foveal vision away from the midline but is not apparent, or functional, when foveal word recognition actually occurs. In contrast, the division in unilateral hemispheric projections that occurs in extrafoveal locations is still apparent, and is functional, when extrafoveal word recognition takes place.
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Affiliation(s)
- Timothy R Jordan
- Faculty of Medicine and Biological Sciences, University of Leicester, Leicester, United Kingdom.
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Whitney C. Preface to the special issue: neural representations in visual word recognition. BRAIN AND LANGUAGE 2011; 118:51-52. [PMID: 21492925 DOI: 10.1016/j.bandl.2011.03.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2011] [Accepted: 03/22/2011] [Indexed: 05/30/2023]
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Luo B, Shan C, Zhu R, Weng X, He S. Functional foveal splitting: evidence from neuropsychological and multimodal MRI investigations in a Chinese patient with a splenium lesion. PLoS One 2011; 6:e23997. [PMID: 21887360 PMCID: PMC3162595 DOI: 10.1371/journal.pone.0023997] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2011] [Accepted: 08/02/2011] [Indexed: 11/27/2022] Open
Abstract
It remains controversial and hotly debated whether foveal information is double-projected to both hemispheres or split at the midline between the two hemispheres. We investigated this issue in a unique patient with lesions in the splenium of the corpus callosum and the left medial occipitotemporal region, through a series of neuropsychological tests and multimodal MRI scans. Behavioral experiments showed that (1) the patient had difficulties in reading simple and compound Chinese characters when they were presented in the foveal but left to the fixation, (2) he failed to recognize the left component of compound characters when the compound characters were presented in the central foveal field, (3) his judgments of the gender of centrally presented chimeric faces were exclusively based on the left half-face and he was unaware that the faces were chimeric. Functional MRI data showed that Chinese characters, only when presented in the right foveal field but not in the left foveal field, activated a region in the left occipitotemporal sulcus in the mid-fusiform, which is recognized as visual word form area. Together with existing evidence in the literature, results of the current study suggest that the representation of foveal stimuli is functionally split at object processing levels.
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Affiliation(s)
- Benyan Luo
- Department of Neurology, First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Chunlei Shan
- Department of Rehabilitation Medicine, First Affiliated Hospital of Nanjing Medical University, Nanjing, China
- * E-mail:
| | - Renjing Zhu
- Department of Neurology, Zhongshan Hospital, Xiamen University, Xiamen, China
| | - Xuchu Weng
- Key Laboratory of Mental Health, Institute of Psychology, Chinese Academy of Sciences, Beijing, China
- The Center for Human Brain Research, Hangzhou Normal University, Hangzhou, China
| | - Sheng He
- Department of Psychology, University of Minnesota, Minneapolis, Minnesota, United States of America
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Almabruk AAA, Paterson KB, McGowan V, Jordan TR. Evaluating effects of divided hemispheric processing on word recognition in foveal and extrafoveal displays: the evidence from Arabic. PLoS One 2011; 6:e18131. [PMID: 21559084 PMCID: PMC3084692 DOI: 10.1371/journal.pone.0018131] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2010] [Accepted: 02/23/2011] [Indexed: 11/30/2022] Open
Abstract
Background Previous studies have claimed that a precise split at the vertical midline of each fovea causes all words to the left and right of fixation to project to the opposite, contralateral hemisphere, and this division in hemispheric processing has considerable consequences for foveal word recognition. However, research in this area is dominated by the use of stimuli from Latinate languages, which may induce specific effects on performance. Consequently, we report two experiments using stimuli from a fundamentally different, non-Latinate language (Arabic) that offers an alternative way of revealing effects of split-foveal processing, if they exist. Methods and Findings Words (and pseudowords) were presented to the left or right of fixation, either close to fixation and entirely within foveal vision, or further from fixation and entirely within extrafoveal vision. Fixation location and stimulus presentations were carefully controlled using an eye-tracker linked to a fixation-contingent display. To assess word recognition, Experiment 1 used the Reicher-Wheeler task and Experiment 2 used the lexical decision task. Results Performance in both experiments indicated a functional division in hemispheric processing for words in extrafoveal locations (in recognition accuracy in Experiment 1 and in reaction times and error rates in Experiment 2) but no such division for words in foveal locations. Conclusions These findings from a non-Latinate language provide new evidence that although a functional division in hemispheric processing exists for word recognition outside the fovea, this division does not extend up to the point of fixation. Some implications for word recognition and reading are discussed.
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Affiliation(s)
- Abubaker A. A. Almabruk
- College of Medicine, Biological Sciences, and Psychology, University of Leicester, Leicester, United Kingdom
| | - Kevin B. Paterson
- College of Medicine, Biological Sciences, and Psychology, University of Leicester, Leicester, United Kingdom
- * E-mail:
| | - Victoria McGowan
- College of Medicine, Biological Sciences, and Psychology, University of Leicester, Leicester, United Kingdom
| | - Timothy R. Jordan
- College of Medicine, Biological Sciences, and Psychology, University of Leicester, Leicester, United Kingdom
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Position of phonetic components may influence how written words are processed in the brain: Evidence from Chinese phonetic compound pronunciation. COGNITIVE AFFECTIVE & BEHAVIORAL NEUROSCIENCE 2011; 10:552-9. [PMID: 21098814 DOI: 10.3758/cabn.10.4.552] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Previous studies have shown a right-visual-field (RVF)/left-hemisphere (LH) advantage in Chinese phonetic compound pronunciation. Here, we contrast the processing of two phonetic compound types: a dominant structure in which a semantic component appears on the left and a phonetic component on the right (SP characters), and a minority structure with the opposite arrangement (PS characters). We show that this RVF/LH advantage was observed only in SP character pronunciation, but not in PS character pronunciation. This result suggests that SP character processing is more LH lateralized than is PS character processing and is consistent with corresponding ERP N170 data. This effect may be due to the dominance of SP characters in the lexicon, which makes readers opt to obtain phonological information from the right of the characters. This study thus shows that the overall information distribution of word components in the lexicon may influence how written words are processed in the brain. Supplemental materials for this article may be downloaded from http://cabn.psychonomic-journals.org/content/supplemental.
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Kraft A, Roehmel J, Olma MC, Schmidt S, Irlbacher K, Brandt SA. Transcranial direct current stimulation affects visual perception measured by threshold perimetry. Exp Brain Res 2010; 207:283-90. [DOI: 10.1007/s00221-010-2453-6] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2010] [Accepted: 09/16/2010] [Indexed: 09/29/2022]
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Jordan TR, Paterson KB, Kurtev S, Xu M. Re-evaluating split-fovea processing in word recognition: Effects of fixation location within words. Cortex 2010; 46:298-309. [PMID: 19576580 DOI: 10.1016/j.cortex.2009.01.008] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2008] [Revised: 07/29/2008] [Accepted: 01/19/2009] [Indexed: 10/21/2022]
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Do our brain hemispheres exchange some stimulus aspects better than others? Neuropsychologia 2010; 48:1637-43. [PMID: 20153761 DOI: 10.1016/j.neuropsychologia.2010.02.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2008] [Revised: 01/07/2010] [Accepted: 02/05/2010] [Indexed: 11/24/2022]
Abstract
The communication between the two brain hemispheres involves considerable information losses. This study investigated whether these losses might be reduced for frequently processed stimulus attributes and currently attended stimulus properties. It was assumed that size should be more often processed than animateness, since estimating object size is essential for motor planning. Thus, if the transfer deficits were curbed for frequently processed stimulus aspects, then they should be smaller for size than for animateness. By contrast, if the transfer losses were reduced for currently attended stimulus features, then they should depend on the task: in a size judgement task they should be smaller for size, and in an animateness judgement task they should be smaller for animateness. To test the interhemispheric transmission of the two stimulus properties, a lateralized priming paradigm was implemented, in which one group of participants judged targets according to their size and another group according to their animateness. It was found that the transfer deficits were virtually absent for size, but very pronounced for animateness. Hence, the present data provide the first evidence that interhemispheric transmission losses vary for particular stimulus features and that they may be reduced with practice. Since there was no priming for unattended stimulus properties, it remains open whether attention to certain stimulus aspects can improve the interhemispheric exchange as well.
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Split fovea theory and the role of the two cerebral hemispheres in reading: A review of the evidence. Neuropsychologia 2010; 48:353-65. [DOI: 10.1016/j.neuropsychologia.2009.08.021] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2009] [Revised: 08/20/2009] [Accepted: 08/25/2009] [Indexed: 11/22/2022]
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Van der Haegen L, Drieghe D, Brysbaert M. The Split Fovea Theory and the Leicester critique: What do the data say? Neuropsychologia 2010; 48:96-106. [DOI: 10.1016/j.neuropsychologia.2009.08.014] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2009] [Revised: 07/28/2009] [Accepted: 08/12/2009] [Indexed: 10/20/2022]
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Ellis AW, Ferreira R, Cathles-Hagan P, Holt K, Jarvis L, Barca L. Word learning and the cerebral hemispheres: from serial to parallel processing of written words. Philos Trans R Soc Lond B Biol Sci 2009; 364:3675-96. [PMID: 19933140 PMCID: PMC2846318 DOI: 10.1098/rstb.2009.0187] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Reading familiar words differs from reading unfamiliar non-words in two ways. First, word reading is faster and more accurate than reading of unfamiliar non-words. Second, effects of letter length are reduced for words, particularly when they are presented in the right visual field in familiar formats. Two experiments are reported in which right-handed participants read aloud non-words presented briefly in their left and right visual fields before and after training on those items. The non-words were interleaved with familiar words in the naming tests. Before training, naming was slow and error prone, with marked effects of length in both visual fields. After training, fewer errors were made, naming was faster, and the effect of length was much reduced in the right visual field compared with the left. We propose that word learning creates orthographic word forms in the mid-fusiform gyrus of the left cerebral hemisphere. Those word forms allow words to access their phonological and semantic representations on a lexical basis. But orthographic word forms also interact with more posterior letter recognition systems in the middle/inferior occipital gyri, inducing more parallel processing of right visual field words than is possible for any left visual field stimulus, or for unfamiliar non-words presented in the right visual field.
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Affiliation(s)
- Andrew W Ellis
- Department of Psychology, University of York, York YO10 5DD, UK.
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Marzi CA, Mancini F, Sperandio I, Savazzi S. Evidence of midline retinal nasotemporal overlap in healthy humans: A model for foveal sparing in hemianopia? Neuropsychologia 2009; 47:3007-11. [PMID: 19465034 DOI: 10.1016/j.neuropsychologia.2009.05.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2009] [Revised: 05/13/2009] [Accepted: 05/14/2009] [Indexed: 11/28/2022]
Affiliation(s)
- C A Marzi
- Department of Neurological & Visual Sciences, University of Verona and National Institute of Neuroscience, Verona, Italy.
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Jordan TR, Paterson KB. Re-evaluating split-fovea processing in word recognition: A critical assessment of recent research. Neuropsychologia 2009; 47:2341-53. [PMID: 18723038 DOI: 10.1016/j.neuropsychologia.2008.07.020] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2008] [Revised: 07/08/2008] [Accepted: 07/20/2008] [Indexed: 10/21/2022]
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