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Paré S, Bleau M, Dricot L, Ptito M, Kupers R. Brain structural changes in blindness: a systematic review and an anatomical likelihood estimation (ALE) meta-analysis. Neurosci Biobehav Rev 2023; 150:105165. [PMID: 37054803 DOI: 10.1016/j.neubiorev.2023.105165] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Revised: 03/23/2023] [Accepted: 04/09/2023] [Indexed: 04/15/2023]
Abstract
In recent decades, numerous structural brain imaging studies investigated purported morphometric changes in early (EB) and late onset blindness (LB). The results of these studies have not yielded very consistent results, neither with respect to the type, nor to the anatomical locations of the brain morphometric alterations. To better characterize the effects of blindness on brain morphometry, we performed a systematic review and an Anatomical-Likelihood-Estimation (ALE) coordinate-based-meta-analysis of 65 eligible studies on brain structural changes in EB and LB, including 890 EB, 466 LB and 1257 sighted controls. Results revealed atrophic changes throughout the whole extent of the retino-geniculo-striate system in both EB and LB, whereas changes in areas beyond the occipital lobe occurred in EB only. We discuss the nature of some of the contradictory findings with respect to the used brain imaging methodologies and characteristics of the blind populations such as the onset, duration and cause of blindness. Future studies should aim for much larger sample sizes, eventually by merging data from different brain imaging centers using the same imaging sequences, opt for multimodal structural brain imaging, and go beyond a purely structural approach by combining functional with structural connectivity network analyses.
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Affiliation(s)
- Samuel Paré
- School of Optometry, University of Montreal, Montreal, Qc, Canada
| | - Maxime Bleau
- School of Optometry, University of Montreal, Montreal, Qc, Canada
| | - Laurence Dricot
- Institute of NeuroScience (IoNS), Université catholique de Louvain (UCLouvain), Bruxelles, Belgium
| | - Maurice Ptito
- School of Optometry, University of Montreal, Montreal, Qc, Canada; Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Qc, Canada; Department of Neuroscience, University of Copenhagen, Copenhagen, Denmark
| | - Ron Kupers
- School of Optometry, University of Montreal, Montreal, Qc, Canada; Institute of NeuroScience (IoNS), Université catholique de Louvain (UCLouvain), Bruxelles, Belgium; Department of Neuroscience, University of Copenhagen, Copenhagen, Denmark.
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2
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Marins TF, Russo M, Rodrigues EC, Monteiro M, Moll J, Felix D, Bouzas J, Arcanjo H, Vargas CD, Tovar‐Moll F. Reorganization of thalamocortical connections in congenitally blind humans. Hum Brain Mapp 2023; 44:2039-2049. [PMID: 36661404 PMCID: PMC9980890 DOI: 10.1002/hbm.26192] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Revised: 11/14/2022] [Accepted: 11/24/2022] [Indexed: 01/21/2023] Open
Abstract
Cross-modal plasticity in blind individuals has been reported over the past decades showing that nonvisual information is carried and processed by "visual" brain structures. However, despite multiple efforts, the structural underpinnings of cross-modal plasticity in congenitally blind individuals remain unclear. We mapped thalamocortical connectivity and assessed the integrity of white matter of 10 congenitally blind individuals and 10 sighted controls. We hypothesized an aberrant thalamocortical pattern of connectivity taking place in the absence of visual stimuli from birth as a potential mechanism of cross-modal plasticity. In addition to the impaired microstructure of visual white matter bundles, we observed structural connectivity changes between the thalamus and occipital and temporal cortices. Specifically, the thalamic territory dedicated to connections with the occipital cortex was smaller and displayed weaker connectivity in congenitally blind individuals, whereas those connecting with the temporal cortex showed greater volume and increased connectivity. The abnormal pattern of thalamocortical connectivity included the lateral and medial geniculate nuclei and the pulvinar nucleus. For the first time in humans, a remapping of structural thalamocortical connections involving both unimodal and multimodal thalamic nuclei has been demonstrated, shedding light on the possible mechanisms of cross-modal plasticity in humans. The present findings may help understand the functional adaptations commonly observed in congenitally blind individuals.
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Affiliation(s)
- Theo F. Marins
- D'Or Institute for Research and Education (IDOR)Rio de JaneiroBrazil,Post‐Graduation Program in Morphological Sciences (PCM) of the Institute of Biomedical Sciences (ICB)Federal University of Rio de Janeiro (UFRJ)Rio de JaneiroBrazil
| | - Maite Russo
- Institute of Biophysics Carlos Chagas Filho (IBCCF)Federal University of Rio de Janeiro (UFRJ)Rio de JaneiroBrazil
| | | | - Marina Monteiro
- D'Or Institute for Research and Education (IDOR)Rio de JaneiroBrazil
| | - Jorge Moll
- D'Or Institute for Research and Education (IDOR)Rio de JaneiroBrazil
| | - Daniel Felix
- D'Or Institute for Research and Education (IDOR)Rio de JaneiroBrazil
| | - Julia Bouzas
- D'Or Institute for Research and Education (IDOR)Rio de JaneiroBrazil
| | - Helena Arcanjo
- Centro de Oftalmologia EspecializadaRio de JaneiroBrazil
| | - Claudia D. Vargas
- Institute of Biophysics Carlos Chagas Filho (IBCCF)Federal University of Rio de Janeiro (UFRJ)Rio de JaneiroBrazil
| | - Fernanda Tovar‐Moll
- D'Or Institute for Research and Education (IDOR)Rio de JaneiroBrazil,Post‐Graduation Program in Morphological Sciences (PCM) of the Institute of Biomedical Sciences (ICB)Federal University of Rio de Janeiro (UFRJ)Rio de JaneiroBrazil
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3
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Lin J, Zhang L, Guo R, Jiao S, Song X, Feng S, Wang K, Li M, Luo Y, Han Z. The influence of visual deprivation on the development of the thalamocortical network: Evidence from congenitally blind children and adults. Neuroimage 2022; 264:119722. [PMID: 36323383 DOI: 10.1016/j.neuroimage.2022.119722] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Revised: 10/23/2022] [Accepted: 10/29/2022] [Indexed: 11/06/2022] Open
Abstract
The thalamus is heavily involved in relaying sensory signals to the cerebral cortex. A relevant issue is how the deprivation of congenital visual sensory information modulates the development of the thalamocortical network. The answer is unclear because previous studies on this topic did not investigate network development, structure-function combinations, and cognition-related behaviors in the same study. To overcome these limitations, we recruited 30 congenitally blind subjects (8 children, 22 adults) and 31 sighted subjects (10 children, 21 adults), and conducted multiple analyses [i.e., gray matter volume (GMV) analysis using the voxel-based morphometry (VBM) method, resting-state functional connectivity (FC), and brain-behavior correlation]. We found that congenital blindness elicited significant changes in the development of GMV in visual and somatosensory thalamic regions. Blindness also resulted in significant changes in the development of FC between somatosensory thalamic regions and visual cortical regions as well as advanced information processing regions. Moreover, the somatosensory thalamic regions and their FCs with visual cortical regions were reorganized to process high-level tactile language information in blind individuals. These findings provide a refined understanding of the neuroanatomical and functional plasticity of the thalamocortical network.
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Affiliation(s)
- Junfeng Lin
- State Key Laboratory of Cognitive Neuroscience and Learning & IDG/McGovern Institute for Brain Research, Beijing Normal University, Beijing 100875, China
| | - Linjun Zhang
- School of Chinese as a Second Language, Peking University, Beijing 100091, China
| | - Runhua Guo
- State Key Laboratory of Cognitive Neuroscience and Learning & IDG/McGovern Institute for Brain Research, Beijing Normal University, Beijing 100875, China
| | - Saiyi Jiao
- State Key Laboratory of Cognitive Neuroscience and Learning & IDG/McGovern Institute for Brain Research, Beijing Normal University, Beijing 100875, China
| | - Xiaomeng Song
- State Key Laboratory of Cognitive Neuroscience and Learning & IDG/McGovern Institute for Brain Research, Beijing Normal University, Beijing 100875, China
| | - Suting Feng
- State Key Laboratory of Cognitive Neuroscience and Learning & IDG/McGovern Institute for Brain Research, Beijing Normal University, Beijing 100875, China
| | - Ke Wang
- State Key Laboratory of Cognitive Neuroscience and Learning & IDG/McGovern Institute for Brain Research, Beijing Normal University, Beijing 100875, China
| | - Mingyang Li
- State Key Laboratory of Cognitive Neuroscience and Learning & IDG/McGovern Institute for Brain Research, Beijing Normal University, Beijing 100875, China; Key Laboratory for Biomedical Engineering of Ministry of Education, Department of Biomedical Engineering, College of Biomedical Engineering & Instrument Science, Zhejiang University, Hangzhou 310027, China
| | - Yudan Luo
- State Key Laboratory of Cognitive Neuroscience and Learning & IDG/McGovern Institute for Brain Research, Beijing Normal University, Beijing 100875, China
| | - Zaizhu Han
- State Key Laboratory of Cognitive Neuroscience and Learning & IDG/McGovern Institute for Brain Research, Beijing Normal University, Beijing 100875, China.
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4
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Chen MJ, Huang R, Liang RB, Pan YC, Shu HY, Liao XL, Xu SH, Ying P, Kang M, Zhang LJ, Ge QM, Shao Y. Abnormal Intrinsic Functional Hubs in Corneal Ulcer: Evidence from a Voxel-Wise Degree Centrality Analysis. J Clin Med 2022; 11:jcm11061478. [PMID: 35329804 PMCID: PMC8949159 DOI: 10.3390/jcm11061478] [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: 01/06/2022] [Revised: 02/08/2022] [Accepted: 02/24/2022] [Indexed: 02/01/2023] Open
Abstract
BACKGROUND Numerous anterior neuroimaging researches have revealed that corneal ulcers (CU) are related to changes in cerebral anatomic structure and functional area. Nonetheless, functional characteristics of the brain's network organization still show no definite research results. The study was designed to confirm CU-associated spatial centrality distribution functional network of the whole cerebrum and explore the mechanism through which the larvaceous changed the intrinsic functional hubs. MATERIAL AND METHODS In this study, 40 patients with CU and 40 normal controls (matched in sex, age, and education level) were enrolled in this study to undergo resting-state functional magnetic resonance imaging (fMRI) scans. The differences between the groups were determined by measuring the voxel-wise degree centrality (DC) throughout the whole cerebrum. For the purpose of assessing the correlation between abnormal DC value and clinical variables, the Linear correlation analysis was used. RESULTS Compared with normal controls (NCs), CU patients revealed high DC values in the frontal lobe, precuneus, inferior parietal lobule, posterior cingulate, occipital lobe, and temporal lobe in the brain functional connectivity maps throughout the brain. The intergroup differences also had high similarity on account of different thresholds. In addition, DC values were positively related to the duration of CU in the left middle frontal gyrus. CONCLUSIONS The experimental results revealed that patients with CU showed spatially unnatural intrinsic functional hubs whether DC values increased or decreased. This brings us to a new level of comprehending the functional features of CU and may offer useful information to make us obtain a clear understanding of the dysfunction of CU.
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Ptito M, Bleau M, Djerourou I, Paré S, Schneider FC, Chebat DR. Brain-Machine Interfaces to Assist the Blind. Front Hum Neurosci 2021; 15:638887. [PMID: 33633557 PMCID: PMC7901898 DOI: 10.3389/fnhum.2021.638887] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Accepted: 01/19/2021] [Indexed: 12/31/2022] Open
Abstract
The loss or absence of vision is probably one of the most incapacitating events that can befall a human being. The importance of vision for humans is also reflected in brain anatomy as approximately one third of the human brain is devoted to vision. It is therefore unsurprising that throughout history many attempts have been undertaken to develop devices aiming at substituting for a missing visual capacity. In this review, we present two concepts that have been prevalent over the last two decades. The first concept is sensory substitution, which refers to the use of another sensory modality to perform a task that is normally primarily sub-served by the lost sense. The second concept is cross-modal plasticity, which occurs when loss of input in one sensory modality leads to reorganization in brain representation of other sensory modalities. Both phenomena are training-dependent. We also briefly describe the history of blindness from ancient times to modernity, and then proceed to address the means that have been used to help blind individuals, with an emphasis on modern technologies, invasive (various type of surgical implants) and non-invasive devices. With the advent of brain imaging, it has become possible to peer into the neural substrates of sensory substitution and highlight the magnitude of the plastic processes that lead to a rewired brain. Finally, we will address the important question of the value and practicality of the available technologies and future directions.
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Affiliation(s)
- Maurice Ptito
- École d’Optométrie, Université de Montréal, Montréal, QC, Canada
- Department of Nuclear Medicine, University of Southern Denmark, Odense, Denmark
- Department of Neuroscience, University of Copenhagen, Copenhagen, Denmark
| | - Maxime Bleau
- École d’Optométrie, Université de Montréal, Montréal, QC, Canada
| | - Ismaël Djerourou
- École d’Optométrie, Université de Montréal, Montréal, QC, Canada
| | - Samuel Paré
- École d’Optométrie, Université de Montréal, Montréal, QC, Canada
| | - Fabien C. Schneider
- TAPE EA7423 University of Lyon-Saint Etienne, Saint Etienne, France
- Neuroradiology Unit, University Hospital of Saint-Etienne, Saint-Etienne, France
| | - Daniel-Robert Chebat
- Visual and Cognitive Neuroscience Laboratory (VCN Lab), Department of Psychology, Faculty of Social Sciences and Humanities, Ariel University, Ariel, Israël
- Navigation and Accessibility Research Center of Ariel University (NARCA), Ariel, Israël
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6
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Abnormal Regional Spontaneous Neural Activity in Nonarteritic Anterior Ischemic Optic Neuropathy: A Resting-State Functional MRI Study. Neural Plast 2020; 2020:8826787. [PMID: 32963518 PMCID: PMC7499295 DOI: 10.1155/2020/8826787] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2020] [Revised: 08/19/2020] [Accepted: 08/27/2020] [Indexed: 12/20/2022] Open
Abstract
Objective To explore altered regional neuronal activity in patients with nonarteritic anterior ischemic optic neuropathy (NAION) and its correlation with clinical performances using the regional homogeneity (ReHo) method, which is based on resting-state functional magnetic resonance imaging (fMRI). Method Thirty-one patients with NAION (20 males, 11 females) and 31 age- and sex-matched normal controls (NCs) (20 males, 11 females) were enrolled in the study. All patients underwent ophthalmic examination, including eyesight, intraocular pressure measurement, optimal coherence tomography (OCT), visual field analysis, and fMRI scans. After ReHo was calculated, we investigated group differences in results between the patients and NCs. We analyzed the relationship between ReHo values for different brain regions in patients with NAION and intraocular pressure, visual field analysis, and OCT. A receiver operating characteristic (ROC) curve was used to assess the diagnostic ability of the ReHo method. Results Compared with NCs, patients with NAION exhibited higher ReHo values in the left middle frontal gyrus, left middle cingulate gyrus, left superior temporal gyrus, and left inferior parietal lobule. Additionally, they exhibited lower ReHo values in the right lingual gyrus, left putamen/lentiform nucleus, and left superior parietal lobule. ReHo values in the left superior parietal lobule were negatively correlated with right retinal nerve fiber layer values (r = −0.462, P = 0.01). The area under the ROC curve for each brain region indicated that the ReHo method is a credible means of diagnosing patient with NAION. Conclusion NAION was primarily associated with dysfunction in the default mode network, which may reflect its underlying neural mechanisms.
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7
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Gilissen SR, Arckens L. Posterior parietal cortex contributions to cross-modal brain plasticity upon sensory loss. Curr Opin Neurobiol 2020; 67:16-25. [PMID: 32777707 DOI: 10.1016/j.conb.2020.07.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Revised: 06/30/2020] [Accepted: 07/01/2020] [Indexed: 12/18/2022]
Abstract
Sensory loss causes compensatory behavior, like echolocation upon vision loss or improved visual motion detection upon deafness. This is enabled by recruitment of the deprived cortical area by the intact senses. Such cross-modal plasticity can however hamper rehabilitation via sensory substitution devices. To steer rehabilitation towards the desired outcome for the patient, having control over the cross-modal take-over is essential. Evidence accumulates to support a role for the posterior parietal cortex (PPC) in multimodal plasticity. This area shows increased activity after sensory loss, keeping similar functions but driven by other senses. Patient-specific factors like stress, social situation, age and attention, have a significant influence on the PPC and on cross-modal plasticity. We propose that understanding the response of the PPC to sensory loss and context is extremely important for determining the best possible implant-based therapies, and that mouse research holds potential to help unraveling the underlying anatomical, cellular and neuromodulatory mechanisms.
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Affiliation(s)
- Sara Rj Gilissen
- KU Leuven, Department of Biology & Leuven Brain Institute, 3000 Leuven, Belgium
| | - Lutgarde Arckens
- KU Leuven, Department of Biology & Leuven Brain Institute, 3000 Leuven, Belgium.
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8
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Ricciardi E, Bottari D, Ptito M, Röder B, Pietrini P. The sensory-deprived brain as a unique tool to understand brain development and function. Neurosci Biobehav Rev 2020; 108:78-82. [DOI: 10.1016/j.neubiorev.2019.10.017] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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9
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Müller F, Niso G, Samiee S, Ptito M, Baillet S, Kupers R. A thalamocortical pathway for fast rerouting of tactile information to occipital cortex in congenital blindness. Nat Commun 2019; 10:5154. [PMID: 31727882 PMCID: PMC6856176 DOI: 10.1038/s41467-019-13173-7] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2018] [Accepted: 10/21/2019] [Indexed: 11/09/2022] Open
Abstract
In congenitally blind individuals, the occipital cortex responds to various nonvisual inputs. Some animal studies raise the possibility that a subcortical pathway allows fast re-routing of tactile information to the occipital cortex, but this has not been shown in humans. Here we show using magnetoencephalography (MEG) that tactile stimulation produces occipital cortex activations, starting as early as 35 ms in congenitally blind individuals, but not in blindfolded sighted controls. Given our measured thalamic response latencies of 20 ms and a mean estimated lateral geniculate nucleus to primary visual cortex transfer time of 15 ms, we claim that this early occipital response is mediated by a direct thalamo-cortical pathway. We also observed stronger directed connectivity in the alpha band range from posterior thalamus to occipital cortex in congenitally blind participants. Our results strongly suggest the contribution of a fast thalamo-cortical pathway in the cross-modal activation of the occipital cortex in congenitally blind humans. In congenitally blind people, tactile stimuli can activate the occipital (visual) cortex. Here, the authors show using magnetoencephalography (MEG) that occipital activation can occur within 35 ms following tactile stimulation, suggesting the existence of a fast thalamocortical pathway for touch in congenitally blind humans.
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Affiliation(s)
- Franziska Müller
- BRAINlab, Department of Neuroscience, Panum Institute, University of Copenhagen, Copenhagen, Denmark
| | - Guiomar Niso
- McConnell Brain Imaging Centre, Montreal Neurological Institute, McGill University, Montreal, QC, Canada.,Centre for Biomedical Technology, Universidad Politécnica de Madrid, Madrid, Spain.,Biomedical Image Technologies, ETSI Telecomunicación, Universidad Politécnica de Madrid and CIBER-BBN, Madrid, Spain
| | - Soheila Samiee
- McConnell Brain Imaging Centre, Montreal Neurological Institute, McGill University, Montreal, QC, Canada
| | - Maurice Ptito
- BRAINlab, Department of Neuroscience, Panum Institute, University of Copenhagen, Copenhagen, Denmark.,École d'Optométrie, Université de Montréal, Montréal, QC, Canada
| | - Sylvain Baillet
- McConnell Brain Imaging Centre, Montreal Neurological Institute, McGill University, Montreal, QC, Canada.
| | - Ron Kupers
- BRAINlab, Department of Neuroscience, Panum Institute, University of Copenhagen, Copenhagen, Denmark. .,École d'Optométrie, Université de Montréal, Montréal, QC, Canada. .,Department of Radiology & Biomedical Imaging, Yale University, New Haven, CT, USA. .,Institute of Neuroscience, Université catholique de Louvain, Brussels, Belgium.
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10
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Magnetoencephalography: Clinical and Research Practices. Brain Sci 2018; 8:brainsci8080157. [PMID: 30126121 PMCID: PMC6120049 DOI: 10.3390/brainsci8080157] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Revised: 08/07/2018] [Accepted: 08/11/2018] [Indexed: 11/25/2022] Open
Abstract
Magnetoencephalography (MEG) is a neurophysiological technique that detects the magnetic fields associated with brain activity. Synthetic aperture magnetometry (SAM), a MEG magnetic source imaging technique, can be used to construct both detailed maps of global brain activity as well as virtual electrode signals, which provide information that is similar to invasive electrode recordings. This innovative approach has demonstrated utility in both clinical and research settings. For individuals with epilepsy, MEG provides valuable, nonredundant information. MEG accurately localizes the irritative zone associated with interictal spikes, often detecting epileptiform activity other methods cannot, and may give localizing information when other methods fail. These capabilities potentially greatly increase the population eligible for epilepsy surgery and improve planning for those undergoing surgery. MEG methods can be readily adapted to research settings, allowing noninvasive assessment of whole brain neurophysiological activity, with a theoretical spatial range down to submillimeter voxels, and in both humans and nonhuman primates. The combination of clinical and research activities with MEG offers a unique opportunity to advance translational research from bench to bedside and back.
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11
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Visual and Motor Recovery After "Cognitive Therapeutic Exercises" in Cortical Blindness: A Case Study. J Neurol Phys Ther 2018. [PMID: 28628550 DOI: 10.1097/npt.0000000000000189] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
BACKGROUND AND PURPOSE Spontaneous visual recovery is rare after cortical blindness. While visual rehabilitation may improve performance, no visual therapy has been widely adopted, as clinical outcomes are variable and rarely translate into improvements in activities of daily living (ADLs). We explored the potential value of a novel rehabilitation approach "cognitive therapeutic exercises" for cortical blindness. CASE DESCRIPTION The subject of this case study was 48-year-old woman with cortical blindness and tetraplegia after cardiac arrest. Prior to the intervention, she was dependent in ADLs and poorly distinguished shapes and colors after 19 months of standard visual and motor rehabilitation. Computed tomographic images soon after symptom onset demonstrated acute infarcts in both occipital cortices. INTERVENTION The subject underwent 8 months of intensive rehabilitation with "cognitive therapeutic exercises" consisting of discrimination exercises correlating sensory and visual information. OUTCOMES Visual fields increased; object recognition improved; it became possible to watch television; voluntary arm movements improved in accuracy and smoothness; walking improved; and ADL independence and self-reliance increased. Subtraction of neuroimaging acquired before and after rehabilitation showed that focal glucose metabolism increases bilaterally in the occipital poles. DISCUSSION This study demonstrates feasibility of "cognitive therapeutic exercises" in an individual with cortical blindness, who experienced impressive visual and sensorimotor recovery, with marked ADL improvement, more than 2 years after ischemic cortical damage.Video Abstract available for additional insights from the authors (see Video, Supplemental Digital Content 1, available at: http://links.lww.com/JNPT/A173).
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12
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Shao Y, Bao J, Huang X, Zhou FQ, Ye L, Min YL, Yang L, Sethi Z, Yuan Q, Zhou Q. Comparative study of interhemispheric functional connectivity in left eye monocular blindness versus right eye monocular blindness: a resting-state functional MRI study. Oncotarget 2018; 9:14285-14295. [PMID: 29581843 PMCID: PMC5865669 DOI: 10.18632/oncotarget.24487] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Accepted: 01/25/2018] [Indexed: 11/25/2022] Open
Abstract
Objective In the present study, we investigated the brain interhemispheric functional connectivity changes in left eye MB versus right eye MB patients by voxel-mirrored homotopic connectivity (VMHC) methods. Methods A total of 31 patients with MB (15 with left eye MB and 16 with right eye MB), and 31 healthy controls (HCs) closely matched for age were recruited. All subjects underwent functional magnetic resonance imaging (fMRI) examinations. The VMHC method was used to evaluate directly functional interactions between the hemispheres. A one-way ANOVA was performed to determine the regions in which the VMHC differs between the three groups. Patients with MB were distinguished from HCs by a receiver operating characteristic (ROC) curve. The relationships between the mean VMHC signal values in many brain regions and clinical features in MB patients were calculated by pearson correlation analysis. Results Compared with HCs, MB patients had significantly decreased VMHC values in the cuneus/calcarine/lingual gyrus. Furthermore, left eye MB showed decreased VMHC values in the cuneus/calcarine/lingual gyrus and showed increased VMHC values in the insula and middle frontal gyrus compared with HC. In addition, right eye MB showed decreased VMHC values in the cuneus/calcarine/lingual gyrus, primary motor cortex (M1)/primary somatosensory cortex (S1) and superior parietal lobule. Conclusion MB subjects showed abnormal brain interhemispheric functional connectivity in visual pathways. Furthermore, different patterns of brain interhemispheric functional connectivity occurred in the left eye and right eye MB. These VMHC values provide much useful information to explain the neural mechanism changes in MB.
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Affiliation(s)
- Yi Shao
- Department of Ophthalmology, The First Affiliated Hospital of Nanchang University, Nanchang 330006, Jiangxi, China
| | - Jing Bao
- Department of Ophthalmology, The First Affiliated Hospital of Nanchang University, Nanchang 330006, Jiangxi, China
| | - Xin Huang
- Department of Ophthalmology, The First Affiliated Hospital of Nanchang University, Nanchang 330006, Jiangxi, China.,Department of Ophthalmology, The People's Hospital of Hubei Province, Wuhan 430060, Hubei, China
| | - Fu-Qing Zhou
- Department of Radiology, The First Affiliated Hospital of Nanchang University, Nanchang 330006, Jiangxi, China
| | - Lei Ye
- Department of Ophthalmology, The First Affiliated Hospital of Nanchang University, Nanchang 330006, Jiangxi, China
| | - You-Lan Min
- Department of Ophthalmology, The First Affiliated Hospital of Nanchang University, Nanchang 330006, Jiangxi, China
| | - Lin Yang
- Department of Ophthalmology, The First Affiliated Hospital of Nanchang University, Nanchang 330006, Jiangxi, China
| | - Zubin Sethi
- University of Miami, Miami, Florida 33146, USA
| | - Qing Yuan
- Department of Ophthalmology, The First Affiliated Hospital of Nanchang University, Nanchang 330006, Jiangxi, China
| | - Qiong Zhou
- Department of Ophthalmology, The First Affiliated Hospital of Nanchang University, Nanchang 330006, Jiangxi, China
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13
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Yoshida F, Hirata M, Onodera A, Goto T, Sugata H, Yorifuji S. Noninvasive spatiotemporal imaging of neural transmission in the subcortical visual pathway. Sci Rep 2017; 7:4424. [PMID: 28667266 PMCID: PMC5493626 DOI: 10.1038/s41598-017-04700-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Accepted: 05/19/2017] [Indexed: 11/23/2022] Open
Abstract
Spatiotemporal signal transmission in the human subcortical visual pathway has not been directly demonstrated to date. To delineate this signal transmission noninvasively, we investigated the early latency components between 45 ms (P45m) and 75 ms (N75m) of visually-evoked neuromagnetic fields (VEFs). Four healthy volunteers participated in this study. Hemi-visual field light flash stimuli were delivered a total of 1200 times. Neuromagnetic responses were measured with a 160-channel whole-head gradiometer. In three participants, averaged waveforms indicated a subtle but distinct component that peaked with a very early latency at 44.7 ± 2.1 ms with an initial rise latency of 36.8 ± 3.1 ms, followed by a typical prominent cortical component at 75 ms. The moving equivalent current dipoles continuously estimated from P45m to N75m were first localized in the vicinity of the contralateral lateral geniculate body, then rapidly propagated along the optic radiation and finally terminated in the contralateral calcarine fissure. This result indicates that the source of P45m is the lateral geniculate body and that the early latency components P45m–N75m of the VEFs reflect neural transmission in the optic radiation. This is the first report to noninvasively demonstrate the neurophysiological transmission of visual information through the optic radiation.
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Affiliation(s)
- Fumiaki Yoshida
- Endowed Research Department of Clinical Neuroengineering, Global Center for Medical Engineering and Informatics, Osaka University, Suita, Osaka, Japan.,Department of Neurosurgery, Osaka University Medical School, Suita, Osaka, Japan.,Center for Information and Neural Networks (CiNet), National Institute of Information and Communications Technology, and Osaka University, Suita, Osaka, Japan
| | - Masayuki Hirata
- Endowed Research Department of Clinical Neuroengineering, Global Center for Medical Engineering and Informatics, Osaka University, Suita, Osaka, Japan. .,Department of Neurosurgery, Osaka University Medical School, Suita, Osaka, Japan. .,Center for Information and Neural Networks (CiNet), National Institute of Information and Communications Technology, and Osaka University, Suita, Osaka, Japan.
| | - Ayako Onodera
- Division of Functional Diagnostic Science, Osaka University Graduate School of Medicine, Suita, Osaka, Japan
| | - Tetsu Goto
- Department of Neurosurgery, Osaka University Medical School, Suita, Osaka, Japan.,Division of Functional Diagnostic Science, Osaka University Graduate School of Medicine, Suita, Osaka, Japan
| | - Hisato Sugata
- Department of Neurosurgery, Osaka University Medical School, Suita, Osaka, Japan
| | - Shiro Yorifuji
- Division of Functional Diagnostic Science, Osaka University Graduate School of Medicine, Suita, Osaka, Japan
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14
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Ioannides AA, Liu L, Poghosyan V, Kostopoulos GK. Using MEG to Understand the Progression of Light Sleep and the Emergence and Functional Roles of Spindles and K-Complexes. Front Hum Neurosci 2017; 11:313. [PMID: 28670270 PMCID: PMC5472839 DOI: 10.3389/fnhum.2017.00313] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2017] [Accepted: 05/31/2017] [Indexed: 12/20/2022] Open
Abstract
We used tomographic analysis of MEG signals to characterize regional spectral changes in the brain at sleep onset and during light sleep. We identified two key processes that may causally link to loss of consciousness during the quiet or "core" periods of NREM1. First, active inhibition in the frontal lobe leads to delta and theta spectral power increases. Second, activation suppression leads to sharp drop of spectral power in alpha and higher frequencies in posterior parietal cortex. During NREM2 core periods, the changes identified in NREM1 become more widespread, but focal increases also emerge in alpha and low sigma band power in frontal midline cortical structures, suggesting reemergence of some monitoring of internal and external environment. Just before spindles and K-complexes (KCs), the hallmarks of NREM2, we identified focal spectral power changes in pre-frontal cortex, mid cingulate, and areas involved in environmental and internal monitoring, i.e., the rostral and sub-genual anterior cingulate. During both spindles and KCs, alpha and low sigma bands increases. Spindles emerge after further active inhibition (increase in delta power) of the frontal areas responsible for environmental monitoring, while in posterior parietal cortex, power increases in low and high sigma bands. KCs are correlated with increase in alpha power in the monitoring areas. These specific regional changes suggest strong and varied vigilance changes for KCs, but vigilance suppression and sharpening of cognitive processing for spindles. This is consistent with processes designed to ensure accurate and uncorrupted memory consolidation. The changes during KCs suggest a sentinel role: evaluation of the salience of provoking events to decide whether to increase processing and possibly wake up, or to actively inhibit further processing of intruding influences. The regional spectral patterns of NREM1, NREM2, and their dynamic changes just before spindles and KCs reveal an edge effect facilitating the emergence of spindles and KCs and defining the precise loci where they might emerge. In the time domain, the spindles are seen in widespread areas of the cortex just as reported from analysis of intracranial data, consistent with the emerging consensus of a differential topography that depends on the kind of memory stored.
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Affiliation(s)
- Andreas A. Ioannides
- Laboratory for Human Brain Dynamics, AAI Scientific Cultural Services Ltd.Nicosia, Cyprus
| | - Lichan Liu
- Laboratory for Human Brain Dynamics, AAI Scientific Cultural Services Ltd.Nicosia, Cyprus
| | - Vahe Poghosyan
- Laboratory for Human Brain Dynamics, AAI Scientific Cultural Services Ltd.Nicosia, Cyprus
- MEG Unit, Department of Neurophysiology, King Fahad Medical CityRiyadh, Saudi Arabia
| | - George K. Kostopoulos
- Neurophysiology Unit, Department of Physiology, Medical School, University of PatrasRion, Greece
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15
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Thalamocortical Connectivity and Microstructural Changes in Congenital and Late Blindness. Neural Plast 2017; 2017:9807512. [PMID: 28386486 PMCID: PMC5366815 DOI: 10.1155/2017/9807512] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2016] [Revised: 02/02/2017] [Accepted: 02/19/2017] [Indexed: 11/17/2022] Open
Abstract
There is ample evidence that the occipital cortex of congenitally blind individuals processes nonvisual information. It remains a debate whether the cross-modal activation of the occipital cortex is mediated through the modulation of preexisting corticocortical projections or the reorganisation of thalamocortical connectivity. Current knowledge on this topic largely stems from anatomical studies in animal models. The aim of this study was to test whether purported changes in thalamocortical connectivity in blindness can be revealed by tractography based on diffusion-weighted magnetic resonance imaging. To assess the thalamocortical network, we used a clustering method based on the thalamic white matter projections towards predefined cortical regions. Five thalamic clusters were obtained in each group representing their cortical projections. Although we did not find differences in the thalamocortical network between congenitally blind individuals, late blind individuals, and normal sighted controls, diffusion tensor imaging (DTI) indices revealed significant microstructural changes within thalamic clusters of both blind groups. Furthermore, we find a significant decrease in fractional anisotropy (FA) in occipital and temporal thalamocortical projections in both blind groups that were not captured at the network level. This suggests that plastic microstructural changes have taken place, but not in a degree to be reflected in the tractography-based thalamocortical network.
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16
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Roberts MH, Shenker JI. Non-optic vision: Beyond synesthesia? Brain Cogn 2016; 107:24-9. [PMID: 27363006 DOI: 10.1016/j.bandc.2016.05.007] [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: 12/19/2015] [Revised: 05/30/2016] [Accepted: 05/31/2016] [Indexed: 11/17/2022]
Abstract
Patient NS is a 28year-old female who went blind in her early twenties as a result of S-cone syndrome, a degenerative retinal disorder. A few years after losing her vision, she started experiencing visual perceptions of her hands as she moved them and objects that came into contact with her hands. Over the course of a year, these cross-modal sensations evolved to become veridical visual experiences accurately representative of her hands, objects she touched, and to some degree, objects she could infer from her immediate surroundings. We argue that these experiences are distinct from mental imagery as they occurred automatically, remained consistent over time, and were proprioceptively mediated by her head position much like normal optical vision. Moreover, she could neither consciously force these visual experiences to occur without sensory inference nor prevent them from happening when haptically exploring an object. Her previous visual experiences contributed to a strong influence of top-down processing in her perceptions. Though individuals have previously been able to develop limited veridical acquired synesthesia following extensive practice over many years with the use of a special sensory device, none reported experiencing the richness of complexity or degree of top-down processing exhibited by NS. Thus, we posit that NS's case may represent a phenomenon beyond synesthesia altogether.
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Affiliation(s)
| | - Joel I Shenker
- Department of Neurology, University of Missouri, Columbia, MO, USA.
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17
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Kida T, Tanaka E, Kakigi R. Multi-Dimensional Dynamics of Human Electromagnetic Brain Activity. Front Hum Neurosci 2016; 9:713. [PMID: 26834608 PMCID: PMC4717327 DOI: 10.3389/fnhum.2015.00713] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2015] [Accepted: 12/21/2015] [Indexed: 12/21/2022] Open
Abstract
Magnetoencephalography (MEG) and electroencephalography (EEG) are invaluable neuroscientific tools for unveiling human neural dynamics in three dimensions (space, time, and frequency), which are associated with a wide variety of perceptions, cognition, and actions. MEG/EEG also provides different categories of neuronal indices including activity magnitude, connectivity, and network properties along the three dimensions. In the last 20 years, interest has increased in inter-regional connectivity and complex network properties assessed by various sophisticated scientific analyses. We herein review the definition, computation, short history, and pros and cons of connectivity and complex network (graph-theory) analyses applied to MEG/EEG signals. We briefly describe recent developments in source reconstruction algorithms essential for source-space connectivity and network analyses. Furthermore, we discuss a relatively novel approach used in MEG/EEG studies to examine the complex dynamics represented by human brain activity. The correct and effective use of these neuronal metrics provides a new insight into the multi-dimensional dynamics of the neural representations of various functions in the complex human brain.
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Affiliation(s)
- Tetsuo Kida
- Department of Integrative Physiology, National Institute for Physiological SciencesOkazaki, Japan
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18
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Heine L, Bahri MA, Cavaliere C, Soddu A, Laureys S, Ptito M, Kupers R. Prevalence of increases in functional connectivity in visual, somatosensory and language areas in congenital blindness. Front Neuroanat 2015; 9:86. [PMID: 26190978 PMCID: PMC4486836 DOI: 10.3389/fnana.2015.00086] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2015] [Accepted: 06/15/2015] [Indexed: 12/16/2022] Open
Abstract
There is ample evidence that congenitally blind individuals rely more strongly on non-visual information compared to sighted controls when interacting with the outside world. Although brain imaging studies indicate that congenitally blind individuals recruit occipital areas when performing various non-visual and cognitive tasks, it remains unclear through which pathways this is accomplished. To address this question, we compared resting state functional connectivity in a group of congenital blind and matched sighted control subjects. We used a seed-based analysis with a priori specified regions-of-interest (ROIs) within visual, somato-sensory, auditory and language areas. Between-group comparisons revealed increased functional connectivity within both the ventral and the dorsal visual streams in blind participants, whereas connectivity between the two streams was reduced. In addition, our data revealed stronger functional connectivity in blind participants between the visual ROIs and areas implicated in language and tactile (Braille) processing such as the inferior frontal gyrus (Broca's area), thalamus, supramarginal gyrus and cerebellum. The observed group differences underscore the extent of the cross-modal reorganization in the brain and the supra-modal function of the occipital cortex in congenitally blind individuals.
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Affiliation(s)
- Lizette Heine
- Coma Science Group, Cyclotron Research Center and Neurology Department, University and University Hospital of Liège Liège, Belgium
| | - Mohamed A Bahri
- Cyclotron Research Centre, University of Liège Liège, Belgium
| | - Carlo Cavaliere
- Coma Science Group, Cyclotron Research Center and Neurology Department, University and University Hospital of Liège Liège, Belgium ; IRCCS SDN, Istituto di Ricerca Diagnostica e Nucleare Naples, Italy
| | - Andrea Soddu
- Physics and Astronomy Department, Brain and Mind Institute, Western University London, ON, Canada
| | - Steven Laureys
- Coma Science Group, Cyclotron Research Center and Neurology Department, University and University Hospital of Liège Liège, Belgium
| | - Maurice Ptito
- Harland Sanders Chair, School of Optometry, University of Montreal Montreal, QC, Canada ; Brain Research and Integrative Neuroscience Laboratory, Department of Neuroscience and Pharmacology, University of Copenhagen Copenhagen, Denmark ; Laboratory of Neuropsychiatry, Psychiatric Centre Copenhagen and Department of Neuroscience and Pharmacology, University of Copenhagen Copenhagen, Denmark
| | - Ron Kupers
- Harland Sanders Chair, School of Optometry, University of Montreal Montreal, QC, Canada ; Brain Research and Integrative Neuroscience Laboratory, Department of Neuroscience and Pharmacology, University of Copenhagen Copenhagen, Denmark
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19
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Congenital blindness affects diencephalic but not mesencephalic structures in the human brain. Brain Struct Funct 2015; 221:1465-80. [DOI: 10.1007/s00429-014-0984-5] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2014] [Accepted: 12/28/2014] [Indexed: 11/26/2022]
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20
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Honeine JL, Schieppati M. Time-interval for integration of stabilizing haptic and visual information in subjects balancing under static and dynamic conditions. Front Syst Neurosci 2014; 8:190. [PMID: 25339872 PMCID: PMC4186340 DOI: 10.3389/fnsys.2014.00190] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2014] [Accepted: 09/17/2014] [Indexed: 01/22/2023] Open
Abstract
Maintaining equilibrium is basically a sensorimotor integration task. The central nervous system (CNS) continually and selectively weights and rapidly integrates sensory inputs from multiple sources, and coordinates multiple outputs. The weighting process is based on the availability and accuracy of afferent signals at a given instant, on the time-period required to process each input, and possibly on the plasticity of the relevant pathways. The likelihood that sensory inflow changes while balancing under static or dynamic conditions is high, because subjects can pass from a dark to a well-lit environment or from a tactile-guided stabilization to loss of haptic inflow. This review article presents recent data on the temporal events accompanying sensory transition, on which basic information is fragmentary. The processing time from sensory shift to reaching a new steady state includes the time to (a) subtract or integrate sensory inputs; (b) move from allocentric to egocentric reference or vice versa; and (c) adjust the calibration of motor activity in time and amplitude to the new sensory set. We present examples of processes of integration of posture-stabilizing information, and of the respective sensorimotor time-intervals while allowing or occluding vision or adding or subtracting tactile information. These intervals are short, in the order of 1–2 s for different postural conditions, modalities and deliberate or passive shift. They are just longer for haptic than visual shift, just shorter on withdrawal than on addition of stabilizing input, and on deliberate than unexpected mode. The delays are the shortest (for haptic shift) in blind subjects. Since automatic balance stabilization may be vulnerable to sensory-integration delays and to interference from concurrent cognitive tasks in patients with sensorimotor problems, insight into the processing time for balance control represents a critical step in the design of new balance- and locomotion training devices.
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Affiliation(s)
- Jean-Louis Honeine
- Department of Public Health, Experimental and Forensic Medicine, University of Pavia Pavia, Italy
| | - Marco Schieppati
- Department of Public Health, Experimental and Forensic Medicine, University of Pavia Pavia, Italy ; Centro Studi Attività Motorie (CSAM), Fondazione Salvatore Maugeri (IRCSS), Scientific Institute of Pavia Pavia, Italy
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21
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Tomaiuolo F, Campana S, Collins DL, Fonov VS, Ricciardi E, Sartori G, Pietrini P, Kupers R, Ptito M. Morphometric changes of the corpus callosum in congenital blindness. PLoS One 2014; 9:e107871. [PMID: 25255324 PMCID: PMC4177862 DOI: 10.1371/journal.pone.0107871] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2014] [Accepted: 08/20/2014] [Indexed: 01/18/2023] Open
Abstract
We examined the effects of visual deprivation at birth on the development of the corpus callosum in a large group of congenitally blind individuals. We acquired high-resolution T1-weighted MRI scans in 28 congenitally blind and 28 normal sighted subjects matched for age and gender. There was no overall group effect of visual deprivation on the total surface area of the corpus callosum. However, subdividing the corpus callosum into five subdivisions revealed significant regional changes in its three most posterior parts. Compared to the sighted controls, congenitally blind individuals showed a 12% reduction in the splenium, and a 20% increase in the isthmus and the posterior part of the body. A shape analysis further revealed that the bending angle of the corpus callosum was more convex in congenitally blind compared to the sighted control subjects. The observed morphometric changes in the corpus callosum are in line with the well-described cross-modal functional and structural neuroplastic changes in congenital blindness.
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Affiliation(s)
| | - Serena Campana
- Department of General Psychology, University of Padua, Padua, Italy
| | - D. Louis Collins
- McConnell Brain Imaging Centre, Montreal Neurological Institute, McGill University, Montreal, QC, Canada
| | - Vladimir S. Fonov
- McConnell Brain Imaging Centre, Montreal Neurological Institute, McGill University, Montreal, QC, Canada
| | - Emiliano Ricciardi
- Laboratory of Clinical Biochemistry and Molecular Biology, Department of Surgery, Medical, Molecular, and Critical Area Pathology, University of Pisa, Pisa, Italy
- MRI Lab, Fondazione Toscana ‘G. Monasterio’, Pisa, Italy
| | - Giuseppe Sartori
- Department of General Psychology, University of Padua, Padua, Italy
| | - Pietro Pietrini
- Laboratory of Clinical Biochemistry and Molecular Biology, Department of Surgery, Medical, Molecular, and Critical Area Pathology, University of Pisa, Pisa, Italy
- Clinical Psychology Branch, Pisa University Hospital, Pisa, Italy
| | - Ron Kupers
- Harland Sanders Chair in Visual Science, École d’optométrie, Université de Montréal, Montréal, Québec, Canada
- BRAINlab, Department of Neuroscience and Pharmacology, Panum Institute, University of Copenhagen, Copenhagen, Denmark
- * E-mail:
| | - Maurice Ptito
- Harland Sanders Chair in Visual Science, École d’optométrie, Université de Montréal, Montréal, Québec, Canada
- BRAINlab, Department of Neuroscience and Pharmacology, Panum Institute, University of Copenhagen, Copenhagen, Denmark
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22
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Kupers R, Ptito M. Compensatory plasticity and cross-modal reorganization following early visual deprivation. Neurosci Biobehav Rev 2013; 41:36-52. [PMID: 23954750 DOI: 10.1016/j.neubiorev.2013.08.001] [Citation(s) in RCA: 158] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2013] [Revised: 07/30/2013] [Accepted: 08/01/2013] [Indexed: 10/26/2022]
Abstract
For human and non-human primates, vision is one of the most privileged sensory channels used to interact with the environment. The importance of vision is strongly embedded in the organization of the primate brain as about one third of its cortical surface is involved in visual functions. It is therefore not surprising that the absence of vision from birth, or the loss of vision later in life, has huge consequences, both anatomically and functionally. Studies in animals and humans, conducted over the past few decades, have demonstrated that the absence of vision causes massive structural changes that take place not only in the visually deprived cortex but also in other brain areas. These studies have further shown that the visually deprived cortex becomes responsive to a wide variety of non-visual sensory inputs. Recent studies even showed a role of the visually deprived cortex in cognitive processes. At the behavioral level, increases in acuity for auditory and tactile processes have been reported. The study of the congenitally blind brain also offers a unique model to gain better insights into the functioning of the normal sighted brain and to understand to what extent visual experience is necessary for the brain to develop its functional architecture. Finally, the study of the blind brain allows us to investigate how consciousness develops in the absence of vision. How does the brain of someone who has never had any visual perception form an image of the external world? In this paper, we discuss recent findings from animal studies as well as from behavioural and functional brain imaging studies in sighted and blind individuals that address these questions.
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Affiliation(s)
- Ron Kupers
- BRAINlab, Department of Neuroscience & Pharmacology, Panum Institute, University of Copenhagen, Copenhagen, Denmark; École d'Optométrie, Université de Montréal, Montréal, QC, Canada.
| | - Maurice Ptito
- BRAINlab, Department of Neuroscience & Pharmacology, Panum Institute, University of Copenhagen, Copenhagen, Denmark; École d'Optométrie, Université de Montréal, Montréal, QC, Canada
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