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Bonfanti D, Mazzi C, Savazzi S. Mapping the routes of perception: Hemispheric asymmetries in signal propagation dynamics. Psychophysiology 2024; 61:e14529. [PMID: 38279560 DOI: 10.1111/psyp.14529] [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: 06/23/2023] [Revised: 12/14/2023] [Accepted: 01/11/2024] [Indexed: 01/28/2024]
Abstract
The visual system has long been considered equivalent across hemispheres. However, an increasing amount of data shows that functional differences may exist in this regard. We therefore tried to characterize the emergence of visual perception and the spatiotemporal dynamics resulting from the stimulation of visual cortices in order to detect possible interhemispheric asymmetries. Eighteen participants were tested. Each of them received 360 transcranial magnetic stimulation (TMS) pulses at phosphene threshold intensity over left and right early visual areas while electroencephalography was being recorded. After each single pulse, participants had to report the presence or absence of a phosphene. Local mean field power analysis of TMS-evoked potentials showed an effect of both site (left vs. right TMS) of stimulation and hemisphere (ipsilateral vs. contralateral to the TMS): while right TMS determined early stronger activations, left TMS determined later stronger activity in contralateral electrodes. The interhemispheric signal propagation index revealed differences in how TMS-evoked activity spreads: left TMS-induced activity diffused contralaterally more than right stimulation. With regard to phosphenes perception, distinct electrophysiological patterns were found to reflect similar perceptual experiences: left TMS-evoked phosphenes are associated with early occipito-parietal and frontal activity followed by late central activity; right TMS-evoked phosphenes determine only late, fronto-central, and parietal activations. Our results show that left and right occipital TMS elicits differential electrophysiological patterns in the brain, both per se and as a function of phosphene perception. These distinct activation patterns may suggest a different role of the two hemispheres in processing visual information and giving rise to perception.
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Affiliation(s)
- Davide Bonfanti
- Perception and Awareness (PandA) Laboratory, Department of Neuroscience, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
| | - Chiara Mazzi
- Perception and Awareness (PandA) Laboratory, Department of Neuroscience, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
| | - Silvia Savazzi
- Perception and Awareness (PandA) Laboratory, Department of Neuroscience, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
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2
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Ziaul YH, Mittal J, Afroze T, Kumar V. Anton-Babinski Syndrome: A Visual Anosognosia. Cureus 2024; 16:e55679. [PMID: 38586806 PMCID: PMC10997746 DOI: 10.7759/cureus.55679] [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] [Accepted: 03/06/2024] [Indexed: 04/09/2024] Open
Abstract
Anton-Babinski syndrome is a rare extension of cortical blindness following injury to the occipital lobe. The patient behaves as sighted but has visual function derangements. The posterior cerebral artery (PCA) stroke represents 5% to 10% of total strokes. The COVID-19 pandemic has shown a rise in stroke cases. We present a case of this rare PCA stroke, first diagnosed by an ophthalmologist. This case had an inconsistent initial presentation, but subsequent computed tomography of the brain and other neurological investigations confirmed the diagnosis. If such cases are diagnosed early, they could have better management. Timely intervention can decrease morbidity as well as mortality.
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Affiliation(s)
- Yasir H Ziaul
- Department of Ophthalmology, TS Misra Medical College and Hospital, Lucknow, IND
| | - Jimmy Mittal
- Department of Ophthalmology, Vivekananda Polyclinic and Institute of Medical Sciences, Lucknow, IND
| | - Tazeen Afroze
- Department of Family Medicine, Nad Al Hamar Health Center, Dubai, ARE
| | - Vivek Kumar
- Department of Ophthalmology, Vivekananda Polyclinic and Institute of Medical Sciences, Lucknow, IND
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3
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Siviero I, Bonfanti D, Menegaz G, Savazzi S, Mazzi C, Storti SF. Graph Analysis of TMS-EEG Connectivity Reveals Hemispheric Differences following Occipital Stimulation. SENSORS (BASEL, SWITZERLAND) 2023; 23:8833. [PMID: 37960532 PMCID: PMC10650175 DOI: 10.3390/s23218833] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2023] [Revised: 10/23/2023] [Accepted: 10/28/2023] [Indexed: 11/15/2023]
Abstract
(1) Background: Transcranial magnetic stimulation combined with electroencephalography (TMS-EEG) provides a unique opportunity to investigate brain connectivity. However, possible hemispheric asymmetries in signal propagation dynamics following occipital TMS have not been investigated. (2) Methods: Eighteen healthy participants underwent occipital single-pulse TMS at two different EEG sites, corresponding to early visual areas. We used a state-of-the-art Bayesian estimation approach to accurately estimate TMS-evoked potentials (TEPs) from EEG data, which has not been previously used in this context. To capture the rapid dynamics of information flow patterns, we implemented a self-tuning optimized Kalman (STOK) filter in conjunction with the information partial directed coherence (iPDC) measure, enabling us to derive time-varying connectivity matrices. Subsequently, graph analysis was conducted to assess key network properties, providing insight into the overall network organization of the brain network. (3) Results: Our findings revealed distinct lateralized effects on effective brain connectivity and graph networks after TMS stimulation, with left stimulation facilitating enhanced communication between contralateral frontal regions and right stimulation promoting increased intra-hemispheric ipsilateral connectivity, as evidenced by statistical test (p < 0.001). (4) Conclusions: The identified hemispheric differences in terms of connectivity provide novel insights into brain networks involved in visual information processing, revealing the hemispheric specificity of neural responses to occipital stimulation.
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Affiliation(s)
- Ilaria Siviero
- Department of Computer Science, University of Verona, Strada Le Grazie 15, 37134 Verona, Italy;
| | - Davide Bonfanti
- Perception and Awareness (PandA) Lab., Department of Neuroscience, Biomedicine and Movement Science, University of Verona, Piazzale Ludovico Antonio Scuro 10, 37124 Verona, Italy; (D.B.); (S.S.); (C.M.)
| | - Gloria Menegaz
- Department of Engineering for Innovation Medicine, University of Verona, Strada Le Grazie 15, 37134 Verona, Italy;
| | - Silvia Savazzi
- Perception and Awareness (PandA) Lab., Department of Neuroscience, Biomedicine and Movement Science, University of Verona, Piazzale Ludovico Antonio Scuro 10, 37124 Verona, Italy; (D.B.); (S.S.); (C.M.)
| | - Chiara Mazzi
- Perception and Awareness (PandA) Lab., Department of Neuroscience, Biomedicine and Movement Science, University of Verona, Piazzale Ludovico Antonio Scuro 10, 37124 Verona, Italy; (D.B.); (S.S.); (C.M.)
| | - Silvia Francesca Storti
- Department of Engineering for Innovation Medicine, University of Verona, Strada Le Grazie 15, 37134 Verona, Italy;
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Misawa M, Pyatova Y, Sen A, Markowitz M, Markowitz SN, Reber M, Daibert-Nido M. Innovative vision rehabilitation method for hemianopsia: Comparing pre- and post audio-luminous biofeedback training for ocular motility improving visual functions and quality of life. Front Neurol 2023; 14:1151736. [PMID: 37114220 PMCID: PMC10126773 DOI: 10.3389/fneur.2023.1151736] [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: 01/26/2023] [Accepted: 03/22/2023] [Indexed: 04/29/2023] Open
Abstract
Background Homonymous hemianopsia (HH) corresponds to vision loss in one hemi-field secondary to retro-chiasmal injury. Patients with HH experience difficulties in scanning and orientation in their environment. Near vision daily activities such as reading can also be impaired. There is an unmet need for standardized vision rehabilitation protocols for HH. We investigated the effectiveness of biofeedback training (BT), used for vision rehabilitation in patients with central vision loss, in individuals with HH. Methods In this prospective pilot pre/post study, 12 participants, with HH consecutive to brain injury, performed 5 weekly BT sessions for 20 min each under supervision using the Macular Integrity Assessment microperimeter. BT consisted of relocation of the retinal locus 1-4° toward the blind hemi-field. Outcomes measured post-BT were paracentral retinal sensitivity, visual acuity (near vision), fixation stability, contrast sensitivity, reading speed, and visual functioning questionnaire. Statistical analysis was performed using Bayesian paired t-tests. Results Paracentral retinal sensitivity significantly increased by 2.7 ± 0.9 dB in the treated eye in 9/11 of the participants. Significant improvements with medium-to-large effect size were observed for fixation stability (8/12 participants), contrast sensitivity (6/12 participants) and near vision visual acuity (10/12 participants). Reading speed increased by 32.5 ± 32.4 words per minute in 10/11 participants. Quality of vision scores improved significantly with large effect size for visual ability, visual information and mobility. Conclusion BT led to encouraging improvements in visual functions and functional vision in individuals with HH. Further confirmation with larger trials is required.
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Affiliation(s)
- Mariana Misawa
- Toronto Western Hospital, University Health Network, Toronto, ON, Canada
- Department of Ophthalmology and Vision Science, Faculty of Medicine, University of Toronto, Toronto, ON, Canada
| | - Yulia Pyatova
- Department of Ophthalmology and Vision Science, Faculty of Medicine, University of Toronto, Toronto, ON, Canada
| | - Atri Sen
- Toronto Western Hospital, University Health Network, Toronto, ON, Canada
| | - Michelle Markowitz
- Department of Occupational Science and Occupational Therapy, University of Toronto, Toronto, ON, Canada
| | - Samuel N. Markowitz
- Toronto Western Hospital, University Health Network, Toronto, ON, Canada
- Department of Ophthalmology and Vision Science, Faculty of Medicine, University of Toronto, Toronto, ON, Canada
- Donald K. Johnson Eye Institute, Krembil Research Institute, University Health Network, Toronto, ON, Canada
| | - Michael Reber
- Department of Ophthalmology and Vision Science, Faculty of Medicine, University of Toronto, Toronto, ON, Canada
- Donald K. Johnson Eye Institute, Krembil Research Institute, University Health Network, Toronto, ON, Canada
| | - Monica Daibert-Nido
- Toronto Western Hospital, University Health Network, Toronto, ON, Canada
- Department of Ophthalmology and Vision Science, Faculty of Medicine, University of Toronto, Toronto, ON, Canada
- *Correspondence: Monica Daibert-Nido,
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Cortical Visual Impairment in Childhood: 'Blindsight' and the Sprague Effect Revisited. Brain Sci 2021; 11:brainsci11101279. [PMID: 34679344 PMCID: PMC8533908 DOI: 10.3390/brainsci11101279] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Revised: 09/14/2021] [Accepted: 09/24/2021] [Indexed: 11/29/2022] Open
Abstract
The paper discusses and provides support for diverse processes of brain plasticity in visual function after damage in infancy and childhood in comparison with injury that occurs in the adult brain. We provide support and description of neuroplastic mechanisms in childhood that do not seemingly exist in the same way in the adult brain. Examples include the ability to foster the development of thalamocortical connectivities that can circumvent the lesion and reach their cortical destination in the occipital cortex as the developing brain is more efficient in building new connections. Supporting this claim is the fact that in those with central visual field defects we can note that the extrastriatal visual connectivities are greater when a lesion occurs earlier in life as opposed to in the neurologically mature adult. The result is a significantly more optimized system of visual and spatial exploration within the ‘blind’ field of view. The discussion is provided within the context of “blindsight” and the “Sprague Effect”.
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Luckman J, Chokron S, Michowiz S, Belenky E, Toledano H, Zahavi A, Goldenberg-Cohen N. The Need to Look for Visual Deficit After Stroke in Children. Front Neurol 2020; 11:617. [PMID: 32714272 PMCID: PMC7343911 DOI: 10.3389/fneur.2020.00617] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Accepted: 05/27/2020] [Indexed: 11/13/2022] Open
Abstract
Purpose: To evaluate the role of the ophthalmologist in the management of children with arterial stroke, at presentation and during follow-up. Methods: This retrospective case series comprised children with arterial stroke who were followed for at least 12 months in a tertiary pediatric medical center in 2005–2016. Demographic data and findings on radiological neuroimaging and ophthalmological and neurological examination were retrieved from the medical files. Results: The cohort included 26 children with stroke. Underlying disorders included metabolic syndrome (n = 5, 19.2%), cardiac anomaly or Fontan repair (n = 3 each, 11.5%), vascular anomaly (n = 3, 11.5%), head trauma with traumatic dissection (n = 3, 11.5%), and hypercoagulability (n = 1, 3.8%); in eight patients (30.8%), no apparent cause was found. Eleven patients (42.3%) had a non-ophthalmological neurological deficit as a result of the stroke. Eye examination was performed in nine patients (34.6%) during follow-up. Ophthalmological manifestations included hemianopic visual field defect in seven patients (7.7%) and complete blindness and poor visual acuity in one patient each (3.8%). At the last visit, no change in visual function was detected. Conclusion: The variable etiology and presentation of pediatric stroke may mask specific visual signs. Children with arterial stroke should be referred for early ophthalmological evaluation and visual rehabilitation.
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Affiliation(s)
- Judith Luckman
- Department of Radiology, Rabin Medical Center - Beilinson Hospital, Petach Tikva, Israel
| | - Sylvie Chokron
- Responsable de l'Unité Fonctionnelle Vision et Cognition Service de Neurologie Fondation Ophtalmologique Rothschild, Paris, France
| | - Shalom Michowiz
- Department of Neurosurgery, Hadassah Hebrew University, Jerusalem, Israel
| | - Eugenia Belenky
- Department of Neurosurgery, Hadassah Hebrew University, Jerusalem, Israel
| | - Helen Toledano
- Pediatric Oncology, Schneider Children's Medical Center of Israel, Petach Tikva, Israel
| | - Alon Zahavi
- Department of Ophthalmology, Rabin Medical Center - Beilinson Hospital, Petach Tikva, Israel.,Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.,Krieger Eye Research Laboratory, Felsenstein Medical Research Center, Rabin Medical Center, Petach Tikva, Israel
| | - Nitza Goldenberg-Cohen
- Krieger Eye Research Laboratory, Felsenstein Medical Research Center, Rabin Medical Center, Petach Tikva, Israel.,Department of Ophthalmology, Bnai Zion Medical Center, Haifa, Israel.,Faculty of Medicine, Technion - Israel Institute of Technology, Haifa, Israel
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7
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Martinelli F, Perez C, Caetta F, Obadia M, Savatovsky J, Chokron S. Neuroanatomic correlates of visual hallucinations in poststroke hemianopic patients. Neurology 2020; 94:e1885-e1891. [PMID: 32253350 DOI: 10.1212/wnl.0000000000009366] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Accepted: 11/22/2019] [Indexed: 02/06/2023] Open
Abstract
OBJECTIVES Homonymous hemianopia (HH) is the most frequent visual-field defect after a stroke. Some of these patients also have visual hallucinations, the origin and frequency of which remain largely unknown. The aims of this work were to determine the occurrence of visual hallucinations among poststroke hemianopic patients in function of the location (Brodmann areas) of the brain lesion, as determined by MRI, and to study the neuroanatomic correlates of these hallucinations by nature, frequency, and type. METHODS One hundred sixteen patients with HH who had had a stroke in the posterior region, including the occipital lobe, participated in the study. We evaluated the frequency and nature of visual hallucinations with the Questionnaire for Hallucinations in Homonymous Hemianopia. The volume of each patient's brain lesion was modeled in 3 dimensions. RESULTS Of 116 patients with an HH from a cortical infarction, 85 were excluded due to confounding factors associated with hallucinations. In the final cohort of 31 patients matched for lesion location and etiology, 58% had experienced hallucinations. A significant inverse correlation between lesion size and the frequency of visual hallucinations emerged. The presence of visual hallucinations in poststroke hemianopic patients requires a relatively small lesion that includes, at the very least, loss of the striate cortex but that spares Brodmann area 19, 20, and 37. CONCLUSION Our results suggest that visual hallucinations might be due to complex interactions between damaged areas and intact areas of the visual cortex. We discuss these findings regarding models of perception and of visual recognition. Our results also have implications for the clinical care of patients with HH who have had a stroke.
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Affiliation(s)
- Fiora Martinelli
- From the Institut de Neuropsychologie, Neurovision et Neurocognition (F.M., C.P., F.C., S.C.), Service de Neurologie (M.O.), Unité Neurovasculaire, and Service d'Imagerie (J.S.), Fondation Ophtalmologique Adolphe de Rothschild; and Integrative Neuroscience and Cognition Center (F.C., S.C.), CNRS, UMR 8242 et Université Paris-Descartes, Paris, France
| | - Céline Perez
- From the Institut de Neuropsychologie, Neurovision et Neurocognition (F.M., C.P., F.C., S.C.), Service de Neurologie (M.O.), Unité Neurovasculaire, and Service d'Imagerie (J.S.), Fondation Ophtalmologique Adolphe de Rothschild; and Integrative Neuroscience and Cognition Center (F.C., S.C.), CNRS, UMR 8242 et Université Paris-Descartes, Paris, France
| | - Florent Caetta
- From the Institut de Neuropsychologie, Neurovision et Neurocognition (F.M., C.P., F.C., S.C.), Service de Neurologie (M.O.), Unité Neurovasculaire, and Service d'Imagerie (J.S.), Fondation Ophtalmologique Adolphe de Rothschild; and Integrative Neuroscience and Cognition Center (F.C., S.C.), CNRS, UMR 8242 et Université Paris-Descartes, Paris, France
| | - Michaël Obadia
- From the Institut de Neuropsychologie, Neurovision et Neurocognition (F.M., C.P., F.C., S.C.), Service de Neurologie (M.O.), Unité Neurovasculaire, and Service d'Imagerie (J.S.), Fondation Ophtalmologique Adolphe de Rothschild; and Integrative Neuroscience and Cognition Center (F.C., S.C.), CNRS, UMR 8242 et Université Paris-Descartes, Paris, France
| | - Julien Savatovsky
- From the Institut de Neuropsychologie, Neurovision et Neurocognition (F.M., C.P., F.C., S.C.), Service de Neurologie (M.O.), Unité Neurovasculaire, and Service d'Imagerie (J.S.), Fondation Ophtalmologique Adolphe de Rothschild; and Integrative Neuroscience and Cognition Center (F.C., S.C.), CNRS, UMR 8242 et Université Paris-Descartes, Paris, France
| | - Sylvie Chokron
- From the Institut de Neuropsychologie, Neurovision et Neurocognition (F.M., C.P., F.C., S.C.), Service de Neurologie (M.O.), Unité Neurovasculaire, and Service d'Imagerie (J.S.), Fondation Ophtalmologique Adolphe de Rothschild; and Integrative Neuroscience and Cognition Center (F.C., S.C.), CNRS, UMR 8242 et Université Paris-Descartes, Paris, France.
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Sahraie A, Cederblad AMH, Kenkel S, Romano JG. Efficacy and predictors of recovery of function after eye movement training in 296 hemianopic patients. Cortex 2020; 125:149-160. [DOI: 10.1016/j.cortex.2019.12.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2019] [Revised: 08/08/2019] [Accepted: 12/02/2019] [Indexed: 11/29/2022]
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9
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Chokron S, Dubourg L, Garric C, Martinelli F, Perez C. Dissociations between perception and awareness in hemianopia. Restor Neurol Neurosci 2020; 38:189-201. [PMID: 31929128 DOI: 10.3233/rnn-190951] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The most common visual defect to follow a lesion of the retrochiasmal pathways is homonymous hemianopia (HH), whereby patients are blind to the contralesional visual field of each eye. Homonymous hemianopia has been studied in terms of its deleterious consequences on perceptual, cognitive and motor tasks as well as because it represents an interesting model of vision loss after a unilateral lesion of the occipital lobe. From a behavioral perspective, in addition to exhibiting a severe deficit in their contralesional visual field, HH patients can also exhibit dissociations between perception and awareness. Firstly, HH patients suffering from anosognosia may be unaware of their visual field defect. Secondly, HH patients can present with unconscious visual abilities in the blind hemifield, a phenomenon referred to as blindsight. Thirdly, recent reports demonstrate that HH patients can suffer from a subtle deficit in their ipsilesional visual field that they are unaware of, a condition called sightblindness (i.e. the reverse case of 'blindsight'). Finally, HH patients may also exhibit visual hallucinations in their blind field; however, such patients are not systematically aware that their perceptions are unreal. In this review, we provide an overview of the visual-field losses in HH patients after a left or right unilateral occipital lesion. Furthermore, we explore the implications of these four phenomena for models of visual processing and rehabilitation of visual field defects in HH patients. Finally, in contrast to the traditional view that HH is solely a visual-field defect, we discuss why this deficit is an interesting model for studying the dissociation between perception and awareness.
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Affiliation(s)
- Sylvie Chokron
- Integrative Neuroscience and Cognition Center, CNRS, UMR 8242 et Université Paris-Descartes, Paris, France
| | - Lucas Dubourg
- Institut de Neuropsychologie, Neurovision, NeuroCognition, Fondation Ophtalmologique Adolphe de Rothschild, Paris, France.,Integrative Neuroscience and Cognition Center, CNRS, UMR 8242 et Université Paris-Descartes, Paris, France
| | - Clémentine Garric
- Laboratoire de Sciences Cognitives et Affectives, SCALab, CNRS UMR, Faculté de Médecine, Pôle Recherche et Université de Lille, Lille, France
| | - Fiora Martinelli
- Integrative Neuroscience and Cognition Center, CNRS, UMR 8242 et Université Paris-Descartes, Paris, France
| | - Céline Perez
- Institut de Neuropsychologie, Neurovision, NeuroCognition, Fondation Ophtalmologique Adolphe de Rothschild, Paris, France.,Integrative Neuroscience and Cognition Center, CNRS, UMR 8242 et Université Paris-Descartes, Paris, France
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10
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Prefrontal neural dynamics in consciousness. Neuropsychologia 2019; 131:25-41. [DOI: 10.1016/j.neuropsychologia.2019.05.018] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Revised: 05/17/2019] [Accepted: 05/20/2019] [Indexed: 12/11/2022]
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11
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Chokron S, Peyrin C, Perez C. Ipsilesional deficit of selective attention in left homonymous hemianopia and left unilateral spatial neglect. Neuropsychologia 2019; 128:305-314. [DOI: 10.1016/j.neuropsychologia.2018.03.013] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2017] [Revised: 03/06/2018] [Accepted: 03/08/2018] [Indexed: 12/23/2022]
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12
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Dunn MJ, Rushton SK. Lateral visual occlusion does not change walking trajectories. J Vis 2018; 18:11. [PMID: 30208430 PMCID: PMC6141229 DOI: 10.1167/18.9.11] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Difficulties with walking are often reported following brain damage that causes a lateralized loss of awareness on one side. Whether lateralized loss of awareness has a direct causal impact on walking is unknown. A review of the literature on visually guided walking suggests several reasons why a lateralized loss of visual awareness might be expected to lead to difficulties walking. Here, we isolated and examined the effect of lateralized vision loss on walking behavior in real and virtual environments. Healthy young participants walked to a target placed within a real room, in a virtual corridor, or on a virtual ground plane. In the ground-plane condition, the scene either was empty or contained three obstacles. We reduced vision on one side by occluding one eye (Experiment 1 and 2) or removing one hemifield, defined relative to either the head or trunk (Experiment 2), through use of eye patching (Experiment 1) and a virtual-reality system (Experiment 2). Visual-field restrictions did not induce significant deviations in walking paths in any of the occlusion conditions or any of the environments. The results provide further insight into the visual information that guides walking in humans, and suggest that lateralized vision loss on its own is not the primary cause of walking difficulties.
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Affiliation(s)
- Matt J Dunn
- School of Optometry and Vision Sciences, Cardiff University, Cardiff, UK
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13
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Page AG, McManus C, González CP, Chahboun S. Is Beauty in the Hand of the Writer? Influences of Aesthetic Preferences through Script Directions, Cultural, and Neurological Factors: A Literature Review. Front Psychol 2017; 8:1325. [PMID: 28824504 PMCID: PMC5541060 DOI: 10.3389/fpsyg.2017.01325] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2017] [Accepted: 07/19/2017] [Indexed: 12/28/2022] Open
Abstract
Human experience surrounding the appreciation of beauty is not static. Many factors such as script direction and cultural differences directly impact whether, how and why we consider images beautiful. In an earlier study, Pérez González showed that 19th-century Iranian and Spanish professional photographers manifest lateral biases linked to reading writing direction in their compositions. The present paper aims to provide a general review on this topic and intends to highlight the most relevant studies reporting preferences in the appreciation of beauty in individuals with different reading and writing directions and belonging to different cultural backgrounds.
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Affiliation(s)
- Alexander G Page
- Department of Teacher Education, The Norwegian University of Science and TechnologyTrondheim, Norway
| | - Chris McManus
- Research Department of Clinical, Educational and Health Psychology, University College LondonLondon, United Kingdom
| | - Carmen P González
- Interdisciplinary Centre for Science and Technology Studies, Bergischen Universität WuppertalWuppertal, Germany
| | - Sobh Chahboun
- Department of Language and Literature, Norwegian University of Science and TechnologyTrondheim, Norway
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14
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Bollini A, Sanchez-Lopez J, Savazzi S, Marzi CA. Lights from the Dark: Neural Responses from a Blind Visual Hemifield. Front Neurosci 2017; 11:290. [PMID: 28588445 PMCID: PMC5440595 DOI: 10.3389/fnins.2017.00290] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2017] [Accepted: 05/08/2017] [Indexed: 12/24/2022] Open
Abstract
Here we present evidence that a hemianopic patient with a lesion of the left primary visual cortex (V1) showed an unconscious above-chance orientation discrimination with moving rather than static visual gratings presented to the blind hemifield. The patient did not report any perceptual experience of the stimulus features except for a feeling that something appeared in the blind hemifield. Interestingly, in the lesioned left hemisphere, following stimulus presentation to the blind hemifield, we found an event-related potential (ERP) N1 component at a post-stimulus onset latency of 180-260 ms and a source generator in the left BA 19. In contrast, we did not find evidence of the early visual components C1 and P1 and of the later component P300. A positive component (P2a) was recorded between 250 and 320 ms after stimulus onset frontally in both hemispheres. Finally, in the time range 320-440 ms there was a negative peak in right posterior electrodes that was present only for the moving condition. In sum, there were two noteworthy results: Behaviorally, we found evidence of above chance unconscious (blindsight) orientation discrimination with moving but not static stimuli. Physiologically, in contrast to previous studies, we found reliable ERP components elicited by stimuli presented to the blind hemifield at various electrode locations and latencies that are likely to index either the perceptual report of the patient (N1 and P2a) or, the above-chance unconscious performance with moving stimuli as is the case of the posterior ERP negative component. This late component can be considered as the neural correlate of a kind of blindsight enabling feature discrimination only when stimuli are moving and that is subserved by the intact right hemisphere through interhemispheric transfer.
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Affiliation(s)
- Alice Bollini
- Department of Neuroscience, Biomedicine and Movement, University of VeronaVerona, Italy
| | - Javier Sanchez-Lopez
- Department of Neuroscience, Biomedicine and Movement, University of VeronaVerona, Italy.,National Institute of NeuroscienceVerona, Italy
| | - Silvia Savazzi
- Department of Neuroscience, Biomedicine and Movement, University of VeronaVerona, Italy.,National Institute of NeuroscienceVerona, Italy
| | - Carlo A Marzi
- Department of Neuroscience, Biomedicine and Movement, University of VeronaVerona, Italy.,National Institute of NeuroscienceVerona, Italy
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15
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Paramei GV, Favrod O, Sabel BA, Herzog MH. Pathological completion in the intact visual field of hemianopia patients. VISUAL COGNITION 2017. [DOI: 10.1080/13506285.2017.1352056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Affiliation(s)
| | - Ophélie Favrod
- Laboratory of Psychophysics, Brain Mind Institute, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Bernhard A. Sabel
- Institute of Medical Psychology, Otto-von-Guericke University of Magdeburg, Magdeburg, Germany
| | - Michael H. Herzog
- Laboratory of Psychophysics, Brain Mind Institute, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
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16
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Mazzi C, Mazzeo G, Savazzi S. Markers of TMS-evoked visual conscious experience in a patient with altitudinal hemianopia. Conscious Cogn 2017; 54:143-154. [PMID: 28215463 DOI: 10.1016/j.concog.2017.01.022] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2016] [Revised: 01/24/2017] [Accepted: 01/24/2017] [Indexed: 11/29/2022]
Abstract
Transcranial magnetic stimulation (TMS) of the occipital and parietal cortices can induce phosphenes, i.e. visual sensations of light without light entering the eyes. In this paper, we adopted a TMS-EEG interactive co-registration approach with a patient (AM) showing altitudinal hemianopia. Occipital and parietal cortices in both hemispheres were stimulated while concurrently recording EEG signal. Results showed that, for all sites, neural activity differentially encoding for the presence vs. absence of a conscious experience could be found in a cluster of electrodes close to the stimulation site at an early (70ms) time-period after TMS. The present data indicate that both occipital and parietal sites are independent early gatekeepers of perceptual awareness, thus, in line with evidence in favor of early correlates of perceptual awareness. Moreover, these data support the valuable contribution of the TMS-EEG approach in patients with visual field defects to investigate the neural processes responsible for perceptual awareness.
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Affiliation(s)
- Chiara Mazzi
- Perception and Awareness (PandA) Laboratory, Department of Neuroscience, Biomedicine and Movement Sciences, University of Verona, Verona, Italy; National Institute of Neuroscience, Verona, Italy
| | - Gaetano Mazzeo
- Perception and Awareness (PandA) Laboratory, Department of Neuroscience, Biomedicine and Movement Sciences, University of Verona, Verona, Italy; National Institute of Neuroscience, Verona, Italy
| | - Silvia Savazzi
- Perception and Awareness (PandA) Laboratory, Department of Neuroscience, Biomedicine and Movement Sciences, University of Verona, Verona, Italy; National Institute of Neuroscience, Verona, Italy.
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17
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Abstract
This article reviews thermodynamic relationships in the brain in an attempt to consolidate current research in systems neuroscience. The present synthesis supports proposals that thermodynamic information in the brain can be quantified to an appreciable degree of objectivity, that many qualitative properties of information in systems of the brain can be inferred by observing changes in thermodynamic quantities, and that many features of the brain's anatomy and architecture illustrate relatively simple information-energy relationships. The brain may provide a unique window into the relationship between energy and information.
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Affiliation(s)
- Sterling Street
- Department of Cellular Biology, Franklin College of Arts and Sciences, University of Georgia, AthensGA, USA
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18
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Chokron S, Dutton GN. Impact of Cerebral Visual Impairments on Motor Skills: Implications for Developmental Coordination Disorders. Front Psychol 2016; 7:1471. [PMID: 27757087 PMCID: PMC5048540 DOI: 10.3389/fpsyg.2016.01471] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Accepted: 09/13/2016] [Indexed: 12/16/2022] Open
Abstract
Cerebral visual impairment (CVI) has become the primary cause of visual impairment and blindness in children in industrialized countries. Its prevalence has increased sharply, due to increased survival rates of children who sustain severe neurological conditions during the perinatal period. Improved diagnosis has probably contributed to this increase. As in adults, the nature and severity of CVI in children relate to the cause, location and extent of damage to the brain. In the present paper, we define CVI and how this impacts on visual function. We then define developmental coordination disorder (DCD) and discuss the link between CVI and DCD. The neuroanatomical correlates and aetiologies of DCD are also presented in relationship with CVI as well as the consequences of perinatal asphyxia (PA) and preterm birth on the occurrence and nature of DCD and CVI. This paper underlines why there are both clinical and theoretical reasons to disentangle CVI and DCD, and to categorize the features with more precision. In order to offer the most appropriate rehabilitation, we propose a systematic and rapid evaluation of visual function in at-risk children who have survived preterm birth or PA whether or not they have been diagnosed with cerebral palsy or DCD.
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Affiliation(s)
- Sylvie Chokron
- Unité Fonctionnelle Vision and Cognition, Fondation Ophtalmologique RothschildParis, France; Laboratoire de Psychologie de la Perception, UMR 8242, Centre National de la Recherche Scientifique - Université Paris-DescartesParis, France
| | - Gordon N Dutton
- Department of Vision Science, Glasgow Caledonian University Glasgow, UK
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