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Di Dona G, Zamfira DA, Battista M, Battaglini L, Perani D, Ronconi L. The role of parietal beta-band activity in the resolution of visual crowding. Neuroimage 2024; 289:120550. [PMID: 38382861 DOI: 10.1016/j.neuroimage.2024.120550] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Revised: 02/16/2024] [Accepted: 02/19/2024] [Indexed: 02/23/2024] Open
Abstract
Visual crowding is the difficulty in identifying an object when surrounded by neighbouring flankers, representing a bottleneck for object perception. Crowding arises not only from the activity of visual areas but also from parietal areas and fronto-parietal network activity. Parietal areas would provide the dorsal-to-ventral guidance for object identification and the fronto-parietal network would modulate the attentional resolution. Several studies highlighted the relevance of beta oscillations (15-25 Hz) in these areas for visual crowding and other connatural visual phenomena. In the present study, we investigated the differential contribution of beta oscillations in the parietal cortex and fronto-parietal network in the resolution of visual crowding. During a crowding task with letter stimuli, high-definition transcranial Alternating Current Stimulation (tACS) in the beta band (18 Hz) was delivered bilaterally on parietal sites, on the right fronto-parietal network, and in a sham regime. Resting-state EEG was recorded before and after stimulation to measure tACS-induced aftereffects. The influence of crowding was reduced only when tACS was delivered bilaterally on parietal sites. In this condition, beta power was reduced after the stimulation. Furthermore, the magnitude of tACS-induced aftereffects varied as a function of individual differences in beta oscillations. Results corroborate the link between parietal beta oscillations and visual crowding, providing fundamental insights on brain rhythms underlying the dorsal-to-ventral guidance in visual perception and suggesting that beta tACS can induce plastic changes in these areas. Remarkably, these findings open new possibilities for neuromodulatory interventions for disorders characterised by abnormal crowding, such as dyslexia.
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Affiliation(s)
- Giuseppe Di Dona
- Division of Neuroscience, IRCCS San Raffaele Scientific Institute, Via Olgettina 60, 20132 Milano MI, Italy; School of Psychology, Vita-Salute San Raffaele University, Via Olgettina 58, 20132 Milano MI, Italy.
| | - Denisa Adina Zamfira
- Division of Neuroscience, IRCCS San Raffaele Scientific Institute, Via Olgettina 60, 20132 Milano MI, Italy; School of Psychology, Vita-Salute San Raffaele University, Via Olgettina 58, 20132 Milano MI, Italy
| | - Martina Battista
- Division of Neuroscience, IRCCS San Raffaele Scientific Institute, Via Olgettina 60, 20132 Milano MI, Italy; MoMiLab Research Unit, IMT School for Advanced Studies Lucca, Piazza S. Francesco 19, 55100 Lucca LU, Italy
| | - Luca Battaglini
- Dipartimento di Psicologia Generale, University of Padova, Via Venezia 8, 35131 Padova PD, Italy
| | - Daniela Perani
- Division of Neuroscience, IRCCS San Raffaele Scientific Institute, Via Olgettina 60, 20132 Milano MI, Italy; School of Psychology, Vita-Salute San Raffaele University, Via Olgettina 58, 20132 Milano MI, Italy
| | - Luca Ronconi
- Division of Neuroscience, IRCCS San Raffaele Scientific Institute, Via Olgettina 60, 20132 Milano MI, Italy; School of Psychology, Vita-Salute San Raffaele University, Via Olgettina 58, 20132 Milano MI, Italy.
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2
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Di Dona G, Ronconi L. Beta oscillations in vision: a (preconscious) neural mechanism for the dorsal visual stream? Front Psychol 2023; 14:1296483. [PMID: 38155693 PMCID: PMC10753839 DOI: 10.3389/fpsyg.2023.1296483] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Accepted: 11/15/2023] [Indexed: 12/30/2023] Open
Abstract
Neural oscillations in alpha (8-12 Hz) and beta (13-30 Hz) frequency bands are thought to reflect feedback/reentrant loops and large-scale cortical interactions. In the last decades a main effort has been made in linking perception with alpha-band oscillations, with converging evidence showing that alpha oscillations have a key role in the temporal and featural binding of visual input, configuring the alpha rhythm a key determinant of conscious visual experience. Less attention has been historically dedicated to link beta oscillations and visual processing. Nonetheless, increasing studies report that task conditions that require to segregate/integrate stimuli in space, to disentangle local/global shapes, to spatially reorganize visual inputs, and to achieve motion perception or form-motion integration, rely on the activity of beta oscillations, with a main hub in parietal areas. In the present review, we summarize the evidence linking oscillations within the beta band and visual perception. We propose that beta oscillations represent a neural code that supports the functionality of the magnocellular-dorsal (M-D) visual pathway, serving as a fast primary neural code to exert top-down influences on the slower parvocellular-ventral visual pathway activity. Such M-D-related beta activity is proposed to act mainly pre-consciously, providing the spatial coordinates of vision and guiding the conscious extraction of objects identity that are achieved with slower alpha rhythms in ventral areas. Finally, within this new theoretical framework, we discuss the potential role of M-D-related beta oscillations in visuo-spatial attention, oculo-motor behavior and reading (dis)abilities.
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Affiliation(s)
- Giuseppe Di Dona
- Division of Neuroscience, IRCCS San Raffaele Scientific Institute, Milan, Italy
- School of Psychology, Vita-Salute San Raffaele University, Milan, Italy
| | - Luca Ronconi
- Division of Neuroscience, IRCCS San Raffaele Scientific Institute, Milan, Italy
- School of Psychology, Vita-Salute San Raffaele University, Milan, Italy
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3
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Rowe EG, Zhang Y, Garrido MI. Evidence for adaptive myelination of subcortical shortcuts for visual motion perception in healthy adults. Hum Brain Mapp 2023; 44:5641-5654. [PMID: 37608684 PMCID: PMC10619379 DOI: 10.1002/hbm.26467] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Revised: 05/27/2023] [Accepted: 08/08/2023] [Indexed: 08/24/2023] Open
Abstract
Conscious visual motion information follows a cortical pathway from the retina to the lateral geniculate nucleus (LGN) and on to the primary visual cortex (V1) before arriving at the middle temporal visual area (MT/V5). Alternative subcortical pathways that bypass V1 are thought to convey unconscious visual information. One flows from the retina to the pulvinar (PUL) and on to medial temporal visual area (MT); while the other directly connects the LGN to MT. Evidence for these pathways comes from non-human primates and modest-sized studies in humans with brain lesions. Thus, the aim of the current study was to reconstruct these pathways in a large sample of neurotypical individuals and to determine the degree to which these pathways are myelinated, suggesting information flow is rapid. We used the publicly available 7T (N = 98; 'discovery') and 3T (N = 381; 'validation') diffusion magnetic resonance imaging datasets from the Human Connectome Project to reconstruct the PUL-MT (including all subcompartments of the PUL) and LGN-MT pathways. We found more fibre tracts with greater density in the left hemisphere. Although the left PUL-MT path was denser, the bilateral LGN-MT tracts were more heavily myelinated, suggesting faster signal transduction. We suggest that this apparent discrepancy may be due to 'adaptive myelination' caused by more frequent use of the LGN-MT pathway that leads to greater myelination and faster overall signal transmission.
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Affiliation(s)
- Elise G. Rowe
- Melbourne School of Psychological SciencesThe University of MelbourneParkvilleVictoriaAustralia
| | - Yubing Zhang
- Melbourne School of Psychological SciencesThe University of MelbourneParkvilleVictoriaAustralia
| | - Marta I. Garrido
- Melbourne School of Psychological SciencesThe University of MelbourneParkvilleVictoriaAustralia
- Graeme Clark Institute for Biomedical EngineeringThe University of MelbourneParkvilleVictoriaAustralia
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Liu YF, Qian Y, Bi HY. Visual motion processing in Chinese children with developmental dyslexia: An fMRI study. DYSLEXIA (CHICHESTER, ENGLAND) 2022; 28:431-447. [PMID: 36329601 DOI: 10.1002/dys.1726] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Revised: 06/30/2022] [Accepted: 07/21/2022] [Indexed: 06/16/2023]
Abstract
Dorsal stream is an important pathway for visual information transmission. As a part of the dorsal pathway, the middle temporal visual motion areas (V5/MT+) are mainly responsible for visual motion processing and the ability of visual motion processing is closely related to reading. Compared with alphabetic scripts, the visual structure of Chinese characters is more complex and there are no clear grapheme-phoneme correspondence rules. So the ability of visual analysis plays an important role in Chinese character processing. This study first investigated the brain activation of Chinese dyslexic children and children of the same chronological age when they observed coherent motion stimuli. ROI analysis indicated that only the activation of left V5/MT+ was significantly weaker in dyslexics than that in the control group. The activity of the magnocellular-dorsal stream was closely related to orthographic awareness in the combined data (two groups) and the typical children. In dyslexia group, the stronger the activation of V5/MT+ was, the worse the phonological awareness, rapid naming performance and orthographic awareness were. In short, Chinese dyslexic children were deficient in the activation of the left V5/MT+ and the activity of the magnocellular-dorsal pathway was closely related to orthographic awareness in Chinese pupils.
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Affiliation(s)
- Yu-Fei Liu
- CAS Key Laboratory of Behavioral Science, Center for Brain Science and Learning Difficulties, Institute of Psychology, Chinese Academy of Sciences, Beijing, China
- Department of Psychology, University of Chinese Academy of Sciences, Beijing, China
- China Textile and Apparel Press, Beijing, China
| | - Yi Qian
- CAS Key Laboratory of Behavioral Science, Center for Brain Science and Learning Difficulties, Institute of Psychology, Chinese Academy of Sciences, Beijing, China
- Department of Psychology, University of Chinese Academy of Sciences, Beijing, China
- Wuxi Institute of Technology, Wuxi, China
| | - Hong-Yan Bi
- CAS Key Laboratory of Behavioral Science, Center for Brain Science and Learning Difficulties, Institute of Psychology, Chinese Academy of Sciences, Beijing, China
- Department of Psychology, University of Chinese Academy of Sciences, Beijing, China
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5
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Rima S, Kerbyson G, Jones E, Schmid MC. Advantage of detecting visual events in the right hemifield is affected by reading skill. Vision Res 2020; 169:41-48. [PMID: 32172007 PMCID: PMC7103781 DOI: 10.1016/j.visres.2020.03.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Revised: 02/26/2020] [Accepted: 03/01/2020] [Indexed: 01/20/2023]
Abstract
Visual perception is often not homogenous across the visual field and can vary depending on situational demands. The reasons behind this inhomogeneity are not clear. Here we show that directing attention that is consistent with a western reading habit from left to right, results in a ~32% higher sensitivity to detect transient visual events in the right hemifield. This right visual field advantage was largely reduced in individuals with reading difficulties from developmental dyslexia. Similarly, visual detection became more symmetric in skilled readers, when attention was guided opposite to the reading pattern. Taken together, these findings highlight a higher sensitivity in the right visual field for detecting the onset of sudden visual events that is well accounted for by left hemisphere dominated reading habit.
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Affiliation(s)
- Samy Rima
- Universite de Fribourg, Fribourg, Switzerland.
| | - Grace Kerbyson
- Newcastle University, Institute of Neuroscience, Newcastle upon Tyne, United Kingdom
| | - Elizabeth Jones
- Newcastle University, Institute of Neuroscience, Newcastle upon Tyne, United Kingdom
| | - Michael C Schmid
- Newcastle University, Institute of Neuroscience, Newcastle upon Tyne, United Kingdom; Universite de Fribourg, Fribourg, Switzerland.
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Battaglini L, Ghiani A, Casco C, Ronconi L. Parietal tACS at beta frequency improves vision in a crowding regime. Neuroimage 2019; 208:116451. [PMID: 31821867 DOI: 10.1016/j.neuroimage.2019.116451] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2019] [Revised: 11/22/2019] [Accepted: 12/06/2019] [Indexed: 10/25/2022] Open
Abstract
Visual crowding is the inability to discriminate objects when presented with nearby flankers and sets a fundamental limit for conscious perception. Beta oscillations in the parietal cortex were found to be associated to crowding, with higher beta amplitude related to better crowding resilience. An open question is whether beta activity directly and selectively modulates crowding. We employed Transcranial Alternating Current Stimulation (tACS) in the beta band (18-Hz), in the alpha band (10-Hz) or in a sham regime, asking whether 18-Hz tACS would selectively improve the perception of crowded stimuli by increasing parietal beta activity. Resting-state electroencephalography (EEG) was measured before and after stimulation to test the influence of tACS on endogenous oscillations. Consistently with our predictions, we found that 18-Hz tACS, as compared to 10-Hz tACS and sham stimulation, reduced crowding. This improvement was found specifically in the contralateral visual hemifield and was accompanied by an increased amplitude of EEG beta oscillations, confirming an effect on endogenous brain rhythms. These results support a causal relationship between parietal beta oscillations and visual crowding and provide new insights into the precise oscillatory mechanisms involved in human vision.
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Affiliation(s)
- Luca Battaglini
- Department of General Psychology, University of Padova, Italy; Neuro.Vis.U.S. Laboratory, University of Padova, Padova, Italy
| | - Andrea Ghiani
- Department of General Psychology, University of Padova, Italy
| | - Clara Casco
- Department of General Psychology, University of Padova, Italy; Neuro.Vis.U.S. Laboratory, University of Padova, Padova, Italy
| | - Luca Ronconi
- Faculty of Psychology, Vita-Salute San Raffaele University, Milan, Italy; Division of Neuroscience, IRCCS San Raffaele Scientific Institute, Milan, Italy.
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7
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Contemori G, Battaglini L, Barollo M, Ciavarelli A, Casco C. Developmental dyslexia: A deficit in magnocellular-parvocellular co-activation, not simply in pure magnocellular activation. Vision Res 2019; 159:61-67. [DOI: 10.1016/j.visres.2019.03.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Revised: 03/08/2019] [Accepted: 03/20/2019] [Indexed: 01/25/2023]
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Different relationship of magnocellular-dorsal function and reading-related skills between Chinese developing and skilled readers. PLoS One 2017; 12:e0179712. [PMID: 28704422 PMCID: PMC5509136 DOI: 10.1371/journal.pone.0179712] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2016] [Accepted: 06/03/2017] [Indexed: 11/19/2022] Open
Abstract
Previous studies have indicated that the relationship between magnocellular-dorsal (M-D) function and reading-related skills may vary with reading development in readers of alphabetic languages. Since this relationship could be affected by the orthographic depth of writing systems, the present study explored the relationship between M-D function and reading-related skills in Chinese, a writing system with a deeper orthography than alphabetic languages. Thirty-seven primary school students and fifty-one undergraduate students participated. Orthographic and phonological awareness tests were adopted as reading-related skill measurements. A steady-pedestal paradigm was used to assess the low-spatial-frequency contrast thresholds of M-D function. Results showed that M-D function was only correlated with orthographic awareness for adults, revealing an enhancement with reading development; while being related to phonological awareness only for children revealing a developmental decrement. It suggested that the mechanism responsible for the relationship between M-D activity and reading-related skills was affected by the characteristics of literacy development in Chinese.
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9
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Qian Y, Bi Y, Wang X, Zhang YW, Bi HY. Visual dorsal stream is associated with Chinese reading skills: A resting-state fMRI study. BRAIN AND LANGUAGE 2016; 160:42-49. [PMID: 27474853 DOI: 10.1016/j.bandl.2016.07.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2015] [Revised: 06/18/2016] [Accepted: 07/17/2016] [Indexed: 06/06/2023]
Abstract
The present study explored the relationship between visual dorsal stream and Chinese reading by resting-state fMRI technique. We collected the resting-state brain activities and reading skills of Chinese-speaking adult readers. The results showed that the values of amplitude of low frequency fluctuation (ALFF) in right posterior parietal cortex (PPC) and left visual middle temporal area (MT) (two regions of dorsal stream) were significantly correlated with rapid naming (RAN) speed, and the ALFF values of right PPC were correlated with orthographic awareness (OA). Further resting-state functional connectivity (RSFC) analysis revealed that RAN speed was related to RSFCs between dorsal stream areas and reading areas (e.g., left fusiform gyrus, bilateral middle occipital gyrus). OA was correlated with RSFCs between right PPC and left middle occipital gyrus. It suggested that spontaneous activities of visual dorsal stream, as well as connection between it and reading-related areas, were highly associated with Chinese reading skills.
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Affiliation(s)
- Yi Qian
- Key Laboratory of Behavioral Science, Institute of Psychology, Chinese Academy of Sciences, Beijing 100101, China; School of Humanities, Jiangnan University, Wuxi 214122, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yanchao Bi
- State Key Laboratory of Cognitive Neuroscience and Learning & IDG/McGovern Institute for Brain Research, Beijing Normal University, Beijing 100875, China
| | - Xiaosha Wang
- State Key Laboratory of Cognitive Neuroscience and Learning & IDG/McGovern Institute for Brain Research, Beijing Normal University, Beijing 100875, China
| | - Yi-Wei Zhang
- School of Labor and Human Resources, Renmin University of China, Beijing 100086, China
| | - Hong-Yan Bi
- Key Laboratory of Behavioral Science, Institute of Psychology, Chinese Academy of Sciences, Beijing 100101, China.
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10
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Qian Y, Deng Y, Zhao J, Bi HY. Magnocellular-dorsal pathway function is associated with orthographic but not phonological skill: fMRI evidence from skilled Chinese readers. Neuropsychologia 2015; 71:84-90. [PMID: 25813780 DOI: 10.1016/j.neuropsychologia.2015.03.024] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2014] [Revised: 03/18/2015] [Accepted: 03/22/2015] [Indexed: 10/23/2022]
Abstract
Numerous studies have shown that magnocellular-dorsal (MD) pathway function is highly associated with reading ability, which is mostly indexed by phonological skill in alphabetic languages. However, it is less clear how MD pathway function influences phonological skill. As a logographic language, Chinese does not follow grapheme-phoneme correspondence rules, and thus provides a tool for delineating the effects of orthographic and phonological processing on reading. The current study used functional magnetic resonance imaging (fMRI) to measure MD pathway function in a coherent motion detection task for readers skilled in Chinese. A series of tests was used to assess participants' reading abilities, including orthographic and phonological processing skills. Results showed that several cortical regions of the MD pathway, including bilateral middle temporal visual motion areas (MT+) and the right posterior parietal cortex (PPC), were activated during the coherent motion detection task. Moreover, the activation was positively correlated with rapid naming speed, and greater activation in the left MT+ was associated with superior fluency and reduced accuracy in reading, suggesting that this pathway is also involved in modulating the speed of visual processing during reading. The most important finding was that activation of the right PPC was associated with orthographic awareness, but MD pathway activation was not related to phonological awareness. The results suggest that the MD pathway is highly associated with orthographic processing, which in turn influences more general aspects of reading skill.
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Affiliation(s)
- Yi Qian
- Key Laboratory of Behavioral Science, Institute of Psychology, Chinese Academy of Sciences, 16 Lincui Road, Chaoyang District, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yuan Deng
- Key Laboratory of Behavioral Science, Institute of Psychology, Chinese Academy of Sciences, 16 Lincui Road, Chaoyang District, Beijing 100101, China.
| | - Jing Zhao
- Key Laboratory of Behavioral Science, Institute of Psychology, Chinese Academy of Sciences, 16 Lincui Road, Chaoyang District, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Hong-Yan Bi
- Key Laboratory of Behavioral Science, Institute of Psychology, Chinese Academy of Sciences, 16 Lincui Road, Chaoyang District, Beijing 100101, China.
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11
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Improved reading measures in adults with dyslexia following transcranial direct current stimulation treatment. Neuropsychologia 2015; 70:107-13. [PMID: 25701796 DOI: 10.1016/j.neuropsychologia.2015.02.022] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2014] [Revised: 02/11/2015] [Accepted: 02/17/2015] [Indexed: 02/01/2023]
Abstract
To better understand the contribution of the dorsal system to word reading, we explored transcranial direct current stimulation (tDCS) effects when adults with developmental dyslexia received active stimulation over the visual extrastriate area MT/V5, which is dominated by magnocellular input. Stimulation was administered in 5 sessions spread over two weeks, and reading speed and accuracy as well as reading fluency were assessed before, immediately after, and a week after the end of the treatment. A control group of adults with developmental dyslexia matched for age, gender, reading level, vocabulary and block-design WAIS-III sub-tests and reading level was exposed to the same protocol but with sham stimulation. The results revealed that active, but not sham stimulation, significantly improved reading speed and fluency. This finding suggests that the dorsal stream may play a role in efficient retrieval from the orthographic input lexicon in the lexical route. It also underscores the potential of tDCS as an intervention tool for improving reading speed, at least in adults with developmental dyslexia.
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12
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The visual magnocellular-dorsal dysfunction in Chinese children with developmental dyslexia impedes Chinese character recognition. Sci Rep 2014; 4:7068. [PMID: 25412386 PMCID: PMC4238300 DOI: 10.1038/srep07068] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2014] [Accepted: 10/27/2014] [Indexed: 01/25/2023] Open
Abstract
The visual magnocellular-dorsal (M-D) deficit theory of developmental dyslexia (DD) is still highly debated. Many researchers have made great efforts to investigate the relationship between M-D dysfunction and reading disability. Given that visual analysis plays an important role in Chinese reading, the present study tried to examine how the M-D dysfunction affected Chinese character recognition in Chinese children with DD. Sixteen DD children with M-D deficit, fifteen DD children with normal M-D function and twenty-seven age-matched typically developing children participated in this study. A global/local decision task was adopted, in which we manipulated the spatial frequency of target characters to separate an M-D condition from an unfiltered condition. Results of reaction times and error rates showed that in the M-D condition both M-D normal dyslexics and controls exhibited a significant global precedence effect, with faster responses and lower error rates in global decision than in local decision. In contrast, this global advantage was absent for the M-D impaired dyslexics. Accordingly, we propose that the M-D impairment present in some but not all dyslexics might influence global recognition of Chinese characters in this subgroup of children with DD, which might be implicated in their difficulties in learning to read.
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Main KL, Pestilli F, Mezer A, Yeatman J, Martin R, Phipps S, Wandell B. Speed discrimination predicts word but not pseudo-word reading rate in adults and children. BRAIN AND LANGUAGE 2014; 138:27-37. [PMID: 25278418 PMCID: PMC4300234 DOI: 10.1016/j.bandl.2014.09.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2013] [Revised: 04/30/2014] [Accepted: 09/02/2014] [Indexed: 06/03/2023]
Abstract
Visual processing in the magnocellular pathway is a reputed influence on word recognition and reading performance. However, the mechanisms behind this relationship are still unclear. To explore this concept, we measured reading rate, speed-discrimination, and contrast detection thresholds in adults and children with a wide range of reading abilities. We found that speed discrimination thresholds are higher in children than in adults and are correlated with age. Speed discrimination thresholds are also correlated with reading rates but only for real words, not pseudo-words. Conversely, we found no correlations between contrast detection thresholds and the reading rates. We also found no correlations between speed discrimination or contrast detection and WASI subtest scores. These findings indicate that familiarity is a factor in magnocellular operations that may influence reading rate. We suggest this effect supports the idea that the magnocellular pathway contributes to word reading through an analysis of letter position.
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Affiliation(s)
- Keith L Main
- Department of Psychology, Stanford University, Stanford, CA, United States; War Related Illness and Injury Study Center, Veterans Affairs, Palo Alto Health Care System (VAPAHCS), Palo Alto, CA, United States; Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Stanford, CA, United States
| | - Franco Pestilli
- Department of Psychology, Stanford University, Stanford, CA, United States.
| | - Aviv Mezer
- Department of Psychology, Stanford University, Stanford, CA, United States
| | - Jason Yeatman
- Department of Psychology, Stanford University, Stanford, CA, United States
| | - Ryan Martin
- Department of Psychology, Loyola Marymount University, Los Angeles, CA, United States
| | - Stephanie Phipps
- Department of Psychology, Stanford University, Stanford, CA, United States
| | - Brian Wandell
- Department of Psychology, Stanford University, Stanford, CA, United States
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14
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Qian Y, Bi HY. The visual magnocellular deficit in Chinese-speaking children with developmental dyslexia. Front Psychol 2014; 5:692. [PMID: 25071661 PMCID: PMC4084406 DOI: 10.3389/fpsyg.2014.00692] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2014] [Accepted: 06/16/2014] [Indexed: 11/30/2022] Open
Abstract
Many alphabetic studies have evidenced that individuals with developmental dyslexia (DD) have deficits in visual magnocellular (M) pathway. However, there are few studies to investigate the M function of Chinese DD. Chinese is a logographic language, and Chinese characters are complicated in structure. Visual skills and orthographic processing abilities are particularly important for efficient reading in Chinese as compared to alphabetic languages. Therefore, it is necessary to investigate the visual M function of Chinese DD and whether the M function was associated with orthographic skills. In the present study, 26 dyslexic children (mean age: 10.03 years) and 27 age-matched normal children (mean age: 10.37 years) took part in a coherent motion (CM) detection task and an orthographic awareness test. The results showed that dyslexic children had a significantly higher threshold than age-matched children in CM detection task. Meanwhile, children with DD responded more slowly in orthographic awareness test, although the group difference was marginally significant. The results suggested that Chinese dyslexics had deficits both in visual M pathway processing and orthographic processing. In order to investigate the relationship between M function and orthographic skills, we made a correlation analysis between CM threshold and orthographic awareness by merging performance of dyslexic children and age-matched children. The results revealed that CM thresholds were positively correlated with reaction times in orthographic awareness test, suggesting that better M function was related to better orthographic processing skills.
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Affiliation(s)
- Yi Qian
- Key Laboratory of Behavioral Science, Institute of Psychology, Chinese Academy of Sciences Beijing, China ; University of Chinese Academy of Sciences Beijing, China
| | - Hong-Yan Bi
- Key Laboratory of Behavioral Science, Institute of Psychology, Chinese Academy of Sciences Beijing, China
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15
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Very early processing of emotional words revealed in temporoparietal junctions of both hemispheres by EEG and TMS. Exp Brain Res 2014; 232:1267-81. [PMID: 24496490 DOI: 10.1007/s00221-014-3843-y] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2013] [Accepted: 01/10/2014] [Indexed: 10/25/2022]
Abstract
We investigate the contribution of both hemispheres in a lateralised lexical decision paradigm with emotional and neutral words in healthy volunteers. In a first experiment, high-density EEG analysis using source imaging methods revealed early specific participation of the temporoparietal junctions (TPJ) in both hemispheres for the detection of words. Then, in an event-related transcranial magnetic stimulation experiment with the same task, the disruption of left or right TPJ compared with a control stimulation over the vertex showed a slowing that is more pronounced when words are emotional and presented in the left visual field (LVF). This indicates that interference with both left and right TPJ results in impaired processing of words that were presented to the LVF. In addition, these results point to a specific cooperative contribution of the right hemisphere in the processing of words with emotional content compared with neutral words at very early stages. Results from the two experiments can be integrated in a brain-based spatiotemporal model of the early detection of written words.
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Danelli L, Berlingeri M, Bottini G, Ferri F, Vacchi L, Sberna M, Paulesu E. Neural intersections of the phonological, visual magnocellular and motor/cerebellar systems in normal readers: implications for imaging studies on dyslexia. Hum Brain Mapp 2013; 34:2669-87. [PMID: 22736513 PMCID: PMC6870382 DOI: 10.1002/hbm.22098] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2011] [Revised: 03/14/2012] [Accepted: 03/15/2012] [Indexed: 01/27/2023] Open
Abstract
We used fMRI to explore the extent of the anatomical overlap of three neural systems that the literature on developmental dyslexia associates with reading: the auditory phonological, the visual magnocellular, and the motor/cerebellar systems. Twenty-eight normal subjects performed four tasks during fMRI scans: word and pseudoword reading, auditory rhyming for letter names, visual motion perception, and a motor sequence learning task. We found that the left occipitotemporal cortex (OTC), which previous studies reported to be dysfunctional in dyslexia, can be fractionated into different functional areas: an anterior and lateral area that was activated by both reading and auditory rhyming tasks; a posterior area that was commonly activated by both the reading and the motion perception task and a medial/intermediate area, including the so-called Visual Word Form Area, which was specifically activated by the reading task. These results show that the left OTC is an area of segregated convergence of different functional systems. We compared our results with the hypoactivation pattern reported for reading in a previous cross-cultural PET study on 36 dyslexic subjects from three countries. The region of decreased activation in dyslexia overlapped with regions that are specific for reading and those activated during both the auditory rhyming task and the single word and pseudoword reading task described in the present fMRI study. No overlap was found with the activation patterns for the visual motion perception task or for the motor sequence learning task. These observations challenge current theories of dyslexia.
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Affiliation(s)
- Laura Danelli
- Psychology Department, University of Milano-Bicocca, Milan, Italy
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Martínez A, Revheim N, Butler PD, Guilfoyle DN, Dias EC, Javitt DC. Impaired magnocellular/dorsal stream activation predicts impaired reading ability in schizophrenia. Neuroimage Clin 2012; 2:8-16. [PMID: 24179753 PMCID: PMC3777659 DOI: 10.1016/j.nicl.2012.09.006] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2012] [Revised: 09/01/2012] [Accepted: 09/05/2012] [Indexed: 11/21/2022]
Abstract
In healthy humans, passage reading depends upon a critical organizing role played by the magnocellular/dorsal visual pathway. In a recent study, we found a significant correlation between orthographic reading deficits in schizophrenia and deficits in contrast sensitivity to low spatial frequency stimuli, suggesting an underlying magnocellular processing abnormality. The interrelationship between magnocellular dysfunction and passage reading impairments in schizophrenia was investigated in 21 patients with schizophrenia and 17 healthy control volunteers using behavioral and functional MRI (fMRI) based measures. fMRI activation patterns during passage- and single-word reading were evaluated in relation to cortical areas with differential sensitivity to low versus high spatial frequency cortical regions indentified using a phase-encoded fMRI paradigm. On average, patients with schizophrenia read at the 6th grade level, despite completion of more than 12 years of education and estimated normal pre-morbid IQ. Schizophrenia patients also showed significantly impaired contrast sensitivity to low spatial frequencies and abnormal neural activity in response to stimulation with low spatial frequencies, consistent with dysfunction of magnocellular processing. Further, these magnocellular deficits were predictive of poor performance on a standardized psychoeducational test of passage reading. These findings suggest that reading is an important index of cognitive dysfunction in schizophrenia and highlight the contribution of magnocellular dysfunction to overall cognitive impairments in schizophrenia.
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Affiliation(s)
- Antígona Martínez
- Nathan Kline Institute for Psychiatric Research, USA
- University of California, San Diego, USA
| | | | - Pamela D. Butler
- Nathan Kline Institute for Psychiatric Research, USA
- New York University Langone School of Medicine, USA
| | | | - Elisa C. Dias
- Nathan Kline Institute for Psychiatric Research, USA
| | - Daniel C. Javitt
- Nathan Kline Institute for Psychiatric Research, USA
- New York University Langone School of Medicine, USA
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Abrupt and ramped flicker-defined form shows evidence for a large magnocellular impairment in dyslexia. Neuropsychologia 2012; 50:2107-13. [PMID: 22609580 DOI: 10.1016/j.neuropsychologia.2012.05.012] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2011] [Revised: 04/18/2012] [Accepted: 05/11/2012] [Indexed: 11/21/2022]
Abstract
Controversy still exists over whether there is a magnocellular deficit associated with developmental dyslexia. Here we utilised a magnocellular system-biased phantom contour form discrimination task defined by high temporal frequency contrast reversals to compare contrast sensitivity in a group of children with dyslexia and an age- and nonverbal intelligence-matched control group (9-14 years). Stimuli were either abruptly presented for 4 refresh frames (34 ms), or in two reduced transience conditions had contrast progressively ramped on and off over either 4 frames or 10 frames (86 ms). Children in the dyslexia group showed increased contrast thresholds compared with the control group in all three conditions, and thus strong evidence for a magnocellular deficit. Although the absolute size of the differences in threshold scores between control and dyslexic groups increased dramatically between the abrupt and the 4 and 10 frame ramped onset stimuli, the similar effect size across all tasks, and also the similar range of contrast change at the first frame of stimulus presentation across all tasks between groups suggests that a similar neural mechanism could provide the locus of the apparent magnocellular deficit in children with dyslexia for all tasks tested. These results suggest that threshold discrimination of stimuli with low contrast and high temporal frequencies designed to target the magnocellular system, and has great potential for early screening for children at risk of visually derived reading difficulties.
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Chouake T, Levy T, Javitt DC, Lavidor M. Magnocellular training improves visual word recognition. Front Hum Neurosci 2012; 6:14. [PMID: 22363277 PMCID: PMC3277270 DOI: 10.3389/fnhum.2012.00014] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2011] [Accepted: 01/24/2012] [Indexed: 11/13/2022] Open
Abstract
Current research has shown that basic visual networks, such as the magnocellular system, may play a crucial role in reading deficits related to dyslexia. The current study explored the relationship between magnocellular activity and reading abilities; we examined the hypothesis that a repeated usage of the magnocellular stream may improve reading by strengthening crucial neural pathways. Visual training was conducted for five consecutive days using a motion detection task (magnocellular training) and a control task of pattern detection (parvocellular training). Reading abilities of skilled readers were measured before and after the training using a lexical decision task. It was found that low-grade visual training overall can improve speed of lexical decision, but there is some indication that magnocellular training may selectively relate to accuracy. This potential added benefit of accuracy is crucial, and indicates that magnocellular training may have an advantage to parvocellular or general visual training when it comes to reading. This result lends support to the role of basic visual systems in reading, and has potential implications for neurorehabilitation of reading-related deficits.
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Affiliation(s)
- Tara Chouake
- Department of Psychology, Bar Ilan University Ramat-Gan, Israel
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Meng X, Cheng-Lai A, Zeng B, Stein JF, Zhou X. Dynamic visual perception and reading development in Chinese school children. ANNALS OF DYSLEXIA 2011; 61:161-176. [PMID: 21240572 DOI: 10.1007/s11881-010-0049-2] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2007] [Accepted: 11/19/2010] [Indexed: 05/30/2023]
Abstract
The development of reading skills may depend to a certain extent on the development of basic visual perception. The magnocellular theory of developmental dyslexia assumes that deficits in the magnocellular pathway, indicated by less sensitivity in perceiving dynamic sensory stimuli, are responsible for a proportion of reading difficulties experienced by dyslexics. Using a task that measures coherent motion detection threshold, this study examined the relationship between dynamic visual perception and reading development in Chinese children. Experiment 1 compared the performance of 27 dyslexics and their age- and IQ-matched controls in the coherent motion detection task and in a static pattern perception task. Results showed that only in the former task did the dyslexics have a significantly higher threshold than the controls, suggesting that Chinese dyslexics, like some of their Western counterparts, may have deficits in magnocellular pathway. Experiment 2 examined whether dynamic visual processing affects specific cognitive processes in reading. One hundred fifth-grade children were tested on visual perception and reading-related tasks. Regression analyses found that the motion detection threshold accounted for 11% and 12%, respectively, variance in the speed of orthographic similarity judgment and in the accuracy of picture naming after IQ and vocabulary size were controlled. The static pattern detection threshold could not account for any variance. It is concluded that reading development in Chinese depends to a certain extent on the development of dynamic visual perception and its underlying neural pathway and that the impact of visual development can be specifically related to orthographic processing in reading Chinese.
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Affiliation(s)
- Xiangzhi Meng
- Department of Psychology, Peking University, Beijing 100871, China
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Laycock R, Cross AJ, Lourenco T, Crewther SG. Dorsal stream involvement in recognition of objects with transient onset but not with ramped onset. Behav Brain Funct 2011; 7:34. [PMID: 21843368 PMCID: PMC3163526 DOI: 10.1186/1744-9081-7-34] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2011] [Accepted: 08/16/2011] [Indexed: 12/03/2022] Open
Abstract
Background Although the ventral visual stream is understood to be responsible for object recognition, it has been proposed that the dorsal stream may contribute to object recognition by rapidly activating parietal attention mechanisms, prior to ventral stream object processing. Methods To investigate the relative contribution of the dorsal visual stream to object recognition a group of tertiary students were divided into good and poor motion coherence groups and assessed on tasks classically assumed to rely on ventral stream processing. Participants were required to identify simple line drawings in two tasks, one where objects were presented abruptly for 50 ms followed by a white-noise mask, the other where contrast was linearly ramped on and off over 325 ms and replaced with a mask. Results Although both groups only differed in motion coherence performance (a dorsal stream measure), the good motion coherence group showed superior contrast sensitivity for object recognition on the abrupt, but not the ramped presentation tasks. Conclusions We propose that abrupt presentation of objects activated attention mechanisms fed by the dorsal stream, whereas the ramped presentation had reduced transience and thus did not activate dorsal attention mechanisms as well. The results suggest that rapid dorsal stream activation may be required to assist with ventral stream object processing.
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Affiliation(s)
- Robin Laycock
- School of Psychological Science, La Trobe University, Melbourne, Australia.
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