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Fleming LL, Defenderfer M, Demirayak P, Stewart P, Decarlo DK, Visscher KM. Impact of deprivation and preferential usage on functional connectivity between early visual cortex and category selective visual regions. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.17.593020. [PMID: 38798355 PMCID: PMC11118586 DOI: 10.1101/2024.05.17.593020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2024]
Abstract
Human behavior can be remarkably shaped by experience, such as the removal of sensory input. Many studies of conditions such as stroke, limb amputation, and vision loss have examined how the removal of input changes brain function. However, an important question has yet to be answered: when input is lost, does the brain change its connectivity to preferentially use some remaining inputs over others? In individuals with healthy vision, the central portion of the retina is preferentially used for everyday visual tasks, due to its ability to discriminate fine details. However, when central vision is lost in conditions like macular degeneration, peripheral vision must be relied upon for those everyday tasks, with certain portions receiving "preferential" usage over others. Using resting-state fMRI collected during total darkness, we examined how deprivation and preferential usage influence the intrinsic functional connectivity of sensory cortex by studying individuals with selective vision loss due to late stages of macular degeneration. We found that cortical regions representing spared portions of the peripheral retina, regardless of whether they are preferentially used, exhibit plasticity of intrinsic functional connectivity in macular degeneration. Cortical representations of spared peripheral retinal locations showed stronger connectivity to MT, a region involved in processing motion. These results suggest that long-term loss of central vision can produce widespread effects throughout spared representations in early visual cortex, regardless of whether those representations are preferentially used. These findings support the idea that connections to visual cortex maintain the capacity for change well after critical periods of visual development. Highlights Portions of early visual cortex representing central vs. peripheral vision exhibit different patterns of connectivity to category-selective visual regions.When central vision is lost, cortical representations of peripheral vision display stronger functional connections to MT than central representations.When central vision is lost, connectivity to regions selective for tasks that involve central vision (FFA and PHA) are not significantly altered.These effects do not depend on which locations of peripheral vision are used more.
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Yang Y, Yang Z, Lv M, Jia A, Li J, Liao B, Chen J, Wu Z, Shi Y, Xia Y, Yao D, Chen K. Morphological disruption and visual tuning alterations in the primary visual cortex in glaucoma (DBA/2J) mice. Neural Regen Res 2024; 19:220-225. [PMID: 37488870 PMCID: PMC10479843 DOI: 10.4103/1673-5374.375341] [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: 12/26/2022] [Revised: 03/08/2023] [Accepted: 04/01/2023] [Indexed: 07/26/2023] Open
Abstract
Glaucoma is a leading cause of irreversible blindness worldwide, and previous studies have shown that, in addition to affecting the eyes, it also causes abnormalities in the brain. However, it is not yet clear how the primary visual cortex (V1) is altered in glaucoma. This study used DBA/2J mice as a model for spontaneous secondary glaucoma. The aim of the study was to compare the electrophysiological and histomorphological characteristics of neurons in the V1 between 9-month-old DBA/2J mice and age-matched C57BL/6J mice. We conducted single-unit recordings in the V1 of light-anesthetized mice to measure the visually induced responses, including single-unit spiking and gamma band oscillations. The morphology of layer II/III neurons was determined by neuronal nuclear antigen staining and Nissl staining of brain tissue sections. Eighty-seven neurons from eight DBA/2J mice and eighty-one neurons from eight C57BL/6J mice were examined. Compared with the C57BL/6J group, V1 neurons in the DBA/2J group exhibited weaker visual tuning and impaired spatial summation. Moreover, fewer neurons were observed in the V1 of DBA/2J mice compared with C57BL/6J mice. These findings suggest that DBA/2J mice have fewer neurons in the V1 compared with C57BL/6J mice, and that these neurons have impaired visual tuning. Our findings provide a better understanding of the pathological changes that occur in V1 neuron function and morphology in the DBA/2J mouse model. This study might offer some innovative perspectives regarding the treatment of glaucoma.
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Affiliation(s)
- Yin Yang
- Department of Ophthalmology, Sichuan Provincial People’s Hospital, Medical School, University of Electronic Science and Technology of China, Chengdu, Sichuan Province, China
| | - Zhaoxi Yang
- Department of Ophthalmology, Sichuan Provincial People’s Hospital, Medical School, University of Electronic Science and Technology of China, Chengdu, Sichuan Province, China
| | - Maoxia Lv
- Department of Ophthalmology, Sichuan Provincial People’s Hospital, Medical School, University of Electronic Science and Technology of China, Chengdu, Sichuan Province, China
| | - Ang Jia
- The Clinical Hospital of Chengdu Brain Science Institute, MOE Key Lab for NeuroInformation, School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu, Sichuan Province, China
| | - Junjun Li
- The Clinical Hospital of Chengdu Brain Science Institute, MOE Key Lab for NeuroInformation, School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu, Sichuan Province, China
| | - Baitao Liao
- The Clinical Hospital of Chengdu Brain Science Institute, MOE Key Lab for NeuroInformation, School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu, Sichuan Province, China
| | - Jing’an Chen
- Research Unit of NeuroInformation, Chinese Academy of Medical Sciences, Chengdu, Sichuan Province, China
- Institute of Basic Medical Sciences Chinese Academy of Medical Sciences, School of Basic Medicine Peking Union Medical College, Beijing, China
| | - Zhengzheng Wu
- Department of Ophthalmology, Sichuan Provincial People’s Hospital, Medical School, University of Electronic Science and Technology of China, Chengdu, Sichuan Province, China
| | - Yi Shi
- Health Management Center, Sichuan Provincial Key Laboratory for Human Disease Gene Study, Sichuan Provincial People’s Hospital, University of Electronic Science and Technology of China, Chengdu, Sichuan Province, China
- Research Unit for Blindness Prevention of Chinese Academy of Medical Sciences (2019RU026), Sichuan Academy of Medical Sciences, Chengdu, Sichuan Province, China
| | - Yang Xia
- Department of Ophthalmology, Sichuan Provincial People’s Hospital, Medical School, University of Electronic Science and Technology of China, Chengdu, Sichuan Province, China
- The Clinical Hospital of Chengdu Brain Science Institute, MOE Key Lab for NeuroInformation, School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu, Sichuan Province, China
| | - Dezhong Yao
- Department of Ophthalmology, Sichuan Provincial People’s Hospital, Medical School, University of Electronic Science and Technology of China, Chengdu, Sichuan Province, China
- The Clinical Hospital of Chengdu Brain Science Institute, MOE Key Lab for NeuroInformation, School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu, Sichuan Province, China
- Research Unit of NeuroInformation, Chinese Academy of Medical Sciences, Chengdu, Sichuan Province, China
- School of Electrical Engineering, Zhengzhou University, Zhengzhou, Henan Province, China
| | - Ke Chen
- Department of Ophthalmology, Sichuan Provincial People’s Hospital, Medical School, University of Electronic Science and Technology of China, Chengdu, Sichuan Province, China
- The Clinical Hospital of Chengdu Brain Science Institute, MOE Key Lab for NeuroInformation, School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu, Sichuan Province, China
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Schone HR, Maimon Mor RO, Kollamkulam M, Gerrand C, Woollard A, Kang NV, Baker CI, Makin TR. Stable Cortical Body Maps Before and After Arm Amputation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.13.571314. [PMID: 38168448 PMCID: PMC10760201 DOI: 10.1101/2023.12.13.571314] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2024]
Abstract
Neuroscientists have long debated the adult brain's capacity to reorganize itself in response to injury. A driving model for studying plasticity has been limb amputation. For decades, it was believed that amputation triggers large-scale reorganization of cortical body resources. However, these studies have relied on cross-sectional observations post-amputation, without directly tracking neural changes. Here, we longitudinally followed adult patients with planned arm amputations and measured hand and face representations, before and after amputation. By interrogating the representational structure elicited from movements of the hand (pre-amputation) and phantom hand (post-amputation), we demonstrate that hand representation is unaltered. Further, we observed no evidence for lower face (lip) reorganization into the deprived hand region. Collectively, our findings provide direct and decisive evidence that amputation does not trigger large-scale cortical reorganization.
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Affiliation(s)
- Hunter R. Schone
- Institute of Cognitive Neuroscience, University College London, London, UK
- Laboratory of Brain & Cognition, National Institutes of Mental Health, National Institutes of Health, Bethesda, Maryland, USA
- Rehab Neural Engineering Labs, University of Pittsburgh, Pittsburgh, PA, USA
- Department of Physical Medicine and Rehabilitation, University of Pittsburgh, Pittsburgh, PA, USA
| | - Roni O. Maimon Mor
- Institute of Cognitive Neuroscience, University College London, London, UK
- Department of Experimental Psychology, University College London, London, UK
- UCL Institute of Ophthalmology, University College London, London, UK
| | - Mathew Kollamkulam
- Institute of Cognitive Neuroscience, University College London, London, UK
- Department of Experimental Psychology, University of Oxford, Oxford, UK
| | - Craig Gerrand
- Department of Orthopaedic Oncology, Royal National Orthopaedic Hospital NHS Trust, Stanmore, Middlesex, UK
| | | | - Norbert V. Kang
- Plastic Surgery Department, Royal Free Hospital NHS Trust, London, UK
| | - Chris I. Baker
- Laboratory of Brain & Cognition, National Institutes of Mental Health, National Institutes of Health, Bethesda, Maryland, USA
| | - Tamar R. Makin
- Institute of Cognitive Neuroscience, University College London, London, UK
- Wellcome Centre for Human Neuroimaging, UCL Institute of Neurology, London, UK
- MRC Cognition and Brain Sciences Unit, University of Cambridge, Cambridge, UK
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4
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Tian M, Xiao X, Hu H, Cusack R, Bedny M. Visual experience shapes functional connectivity between occipital and non-visual networks. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.21.528939. [PMID: 36865300 PMCID: PMC9980152 DOI: 10.1101/2023.02.21.528939] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/23/2023]
Abstract
Comparisons across adults with different sensory histories (blind vs. sighted) have uncovered effects of experience on human brain function. In people born blind visual cortices are responsive to non-visual tasks and show altered functional connectivity at rest. Since almost all research has been done with adults, little is known about the developmental origins of this plasticity. Are infant visual cortices initially functionally like those of sighted adults and blindness causes reorganization? Alternatively, do infants start like blind adults, with vision required to set up the sighted pattern? To distinguish between these possibilities, we compare resting state functional connectivity across blind (n = 30) and blindfolded sighted (n = 50) adults to a large cohort of sighted infants (Developing Human Connectome Project, n = 475). Remarkably, we find that infant secondary visual cortices functionally resemble those of blind more than sighted adults, consistent with the idea that visual experience is required to set up long-range functional connectivity. Primary visual cortices show a mixture of instructive effects of vision and reorganizing effects of blindness. Specifically, in sighted adults, visual cortices show stronger functional coupling with nonvisual sensory-motor networks (i.e., auditory, somatosensory/motor) than with higher-cognitive prefrontal cortices (PFC). In blind adults, visual cortices show stronger coupling with PFC. In infants, connectivity of secondary visual cortices is stronger with PFC, while V1 shows equal sensory-motor/PFC connectivity. In contrast, lateralization of occipital-to-frontal connectivity resembles the sighted adults at birth and is reorganized by blindness, possibly due to recruitment of occipital networks for lateralized cognitive functions, such as language.
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Demirayak P, Deshpande G, Visscher K. Laminar functional magnetic resonance imaging in vision research. Front Neurosci 2022; 16:910443. [PMID: 36267240 PMCID: PMC9577024 DOI: 10.3389/fnins.2022.910443] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Accepted: 08/23/2022] [Indexed: 11/13/2022] Open
Abstract
Magnetic resonance imaging (MRI) scanners at ultra-high magnetic fields have become available to use in humans, thus enabling researchers to investigate the human brain in detail. By increasing the spatial resolution, ultra-high field MR allows both structural and functional characterization of cortical layers. Techniques that can differentiate cortical layers, such as histological studies and electrode-based measurements have made critical contributions to the understanding of brain function, but these techniques are invasive and thus mainly available in animal models. There are likely to be differences in the organization of circuits between humans and even our closest evolutionary neighbors. Thus research on the human brain is essential. Ultra-high field MRI can observe differences between cortical layers, but is non-invasive and can be used in humans. Extensive previous literature has shown that neuronal connections between brain areas that transmit feedback and feedforward information terminate in different layers of the cortex. Layer-specific functional MRI (fMRI) allows the identification of layer-specific hemodynamic responses, distinguishing feedback and feedforward pathways. This capability has been particularly important for understanding visual processing, as it has allowed researchers to test hypotheses concerning feedback and feedforward information in visual cortical areas. In this review, we provide a general overview of successful ultra-high field MRI applications in vision research as examples of future research.
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Affiliation(s)
- Pinar Demirayak
- Civitan International Research Center, University of Alabama at Birmingham, Birmingham, AL, United States
- Department of Neurobiology, University of Alabama at Birmingham, Birmingham, AL, United States
- *Correspondence: Pinar Demirayak,
| | - Gopikrishna Deshpande
- Department of Electrical and Computer Engineering, AU MRI Research Center, Auburn University, Auburn, AL, United States
- Department of Psychological Sciences, Auburn University, Auburn, AL, United States
- Alabama Advanced Imaging Consortium, Birmingham, AL, United States
- Center for Neuroscience, Auburn University, Auburn, AL, United States
- School of Psychology, Capital Normal University, Beijing, China
- Key Laboratory of Learning and Cognition, Capital Normal University, Beijing, China
- Department of Psychiatry, National Institute of Mental Health and Neurosciences, Bangalore, India
- Centre for Brain Research, Indian Institute of Science, Bangalore, India
| | - Kristina Visscher
- Civitan International Research Center, University of Alabama at Birmingham, Birmingham, AL, United States
- Department of Neurobiology, University of Alabama at Birmingham, Birmingham, AL, United States
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In a case of longstanding low vision regions of visual cortex that respond to tactile stimulation of the finger with Braille characters are not causally involved in the discrimination of those same Braille characters. Cortex 2022; 155:277-286. [DOI: 10.1016/j.cortex.2022.07.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Revised: 04/25/2022] [Accepted: 07/19/2022] [Indexed: 11/24/2022]
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7
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Zhu W, Liu T, Li M, Sun X, He S. Activation of lesion projection zone in primary visual cortex is dependent on bilateral central vision loss in patients with end-stage glaucoma. Ophthalmic Physiol Opt 2022; 42:1159-1169. [PMID: 36044240 DOI: 10.1111/opo.13044] [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: 03/16/2022] [Revised: 07/26/2022] [Accepted: 07/26/2022] [Indexed: 11/29/2022]
Abstract
PURPOSE To investigate activation of the lesion projection zone (LPZ) in the primary visual cortex during end-stage glaucoma using functional magnetic resonance imaging (fMRI), as well as the relationship between fMRI responses and clinical data. METHODS Twelve subjects with bilateral end-stage glaucoma (group A), 12 with unilateral end-stage glaucoma (group B) and 12 healthy controls (group C) were enrolled. fMRI was performed under two testing stimuli conditions: passive viewing of a full-field flickering checkerboard and active viewing of a one-back task with scene images. In fMRI analysis, the primary visual cortex was divided into six regions of interest (ROIs). The beta values of the six ROIs were compared across the three groups using one-way analysis of variance under two viewing conditions. Associations between the fMRI beta value and clinical data including multifocal electroretinogram (mfERG), microperimeter-1 and optical coherence tomography were analysed by Spearman correlation. RESULTS The beta values for ROIs 1-3 representing the LPZ were significantly different between the three groups under active viewing conditions, whereas no significant changes were detected under passive viewing. In group A, there were significant differences between all six ROIs for the two viewing conditions, while no significant differences were found in groups B and C. In group A, the P-wave amplitudes of the mfERG was significantly correlated with the beta values of ROIs 1 and 2 under active viewing. In addition, the P-wave latencies of the mfERG were significantly correlated with the beta values for ROIs 2-5. No associations were found between fMRI beta values and clinical data in groups B and C. CONCLUSIONS Activation of the LPZ in the primary visual cortex was observed in patients with bilateral end-stage glaucoma under active viewing conditions. These changes were correlated with residual retinal function.
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Affiliation(s)
- Wenqing Zhu
- Department of Ophthalmology & Visual Science, Eye & ENT Hospital, Shanghai Medical College, Fudan University, Shanghai, China
| | - Tingting Liu
- Department of Ophthalmology & Visual Science, Eye & ENT Hospital, Shanghai Medical College, Fudan University, Shanghai, China
| | - Mengwei Li
- Department of Ophthalmology & Visual Science, Eye & ENT Hospital, Shanghai Medical College, Fudan University, Shanghai, China
| | - Xinghuai Sun
- Department of Ophthalmology & Visual Science, Eye & ENT Hospital, Shanghai Medical College, Fudan University, Shanghai, China.,State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai, China.,NHC Key Laboratory of Myopia, Chinese Academy of Medical Sciences, and Shanghai Key Laboratory of Visual Impairment and Restoration (Fudan University), Shanghai, China
| | - Sheng He
- State Key Laboratory of Brain and Cognitive Science, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
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8
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Rina A, Papanikolaou A, Zong X, Papageorgiou DT, Keliris GA, Smirnakis SM. Visual Motion Coherence Responses in Human Visual Cortex. Front Neurosci 2022; 16:719250. [PMID: 35310109 PMCID: PMC8924467 DOI: 10.3389/fnins.2022.719250] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Accepted: 01/17/2022] [Indexed: 01/24/2023] Open
Abstract
Random dot kinematograms (RDKs) have recently been used to train subjects with cortical scotomas to perform direction of motion discrimination, partially restoring visual motion perception. To study the recovery of visual perception, it is important to understand how visual areas in normal subjects and subjects with cortical scotomas respond to RDK stimuli. Studies in normal subjects have shown that blood oxygen level-dependent (BOLD) responses in human area hV5/MT+ increase monotonically with coherence, in general agreement with electrophysiology studies in primates. However, RDK responses in prior studies were obtained while the subject was performing fixation, not a motion discrimination condition. Furthermore, BOLD responses were gauged against a baseline condition of uniform illumination or static dots, potentially decreasing the specificity of responses for the spatial integration of local motion signals (motion coherence). Here, we revisit this question starting from a baseline RDK condition of no coherence, thereby isolating the component of BOLD response due specifically to the spatial integration of local motion signals. In agreement with prior studies, we found that responses in the area hV5/MT+ of healthy subjects were monotonically increasing when subjects fixated without performing a motion discrimination task. In contrast, when subjects were performing an RDK direction of motion discrimination task, responses in the area hV5/MT+ remained flat, changing minimally, if at all, as a function of motion coherence. A similar pattern of responses was seen in the area hV5/MT+ of subjects with dense cortical scotomas performing direction of motion discrimination for RDKs presented inside the scotoma. Passive RDK presentation within the scotoma elicited no significant hV5/MT+ responses. These observations shed further light on how visual cortex responses behave as a function of motion coherence, helping to prepare the ground for future studies using these methods to study visual system recovery after injury.
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Affiliation(s)
- Andriani Rina
- Department of Neurology Brigham and Women’s Hospital and Jamaica Plain Veterans Administration Hospital, Harvard Medical School, Boston, MA, United States
- Visual and Cognitive Neuroscience, Faculty of Science, University of Tübingen, Tuebingen, Germany
| | - Amalia Papanikolaou
- Department of Experimental Psychology, Institute of Behavioral Neuroscience, University College London, London, United Kingdom
| | - Xiaopeng Zong
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, United States
| | - Dorina T. Papageorgiou
- Department of Physical Medicine and Rehabilitation, Neuroscience, Psychiatry Baylor College of Medicine, Houston, TX, United States
- Department of Electrical and Computer Engineering, Neuroengineering Research Initiative and Applied Physics, Rice University, Houston, TX, United States
| | - Georgios A. Keliris
- Bio-Imaging Lab, University of Antwerp, Antwerp, Belgium
- Max-Planck Institute for Biological Cybernetics, Physiology of Cognitive Processes, Tübingen, Germany
| | - Stelios M. Smirnakis
- Department of Neurology Brigham and Women’s Hospital and Jamaica Plain Veterans Administration Hospital, Harvard Medical School, Boston, MA, United States
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9
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Takemura H, Rosa MGP. Understanding structure-function relationships in the mammalian visual system: part one. Brain Struct Funct 2021; 226:2741-2744. [PMID: 34652532 DOI: 10.1007/s00429-021-02406-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Hiromasa Takemura
- Division of Sensory and Cognitive Brain Mapping, Department of System Neuroscience, National Institute for Physiological Sciences, Okazaki, Japan.
- Department of Physiological Sciences, School of Life Sciences, SOKENDAI (The Graduate University of Advanced Studies), Hayama, Japan.
- Center for Information and Neural Networks (CiNet), Advanced ICT Research Institute, National Institute of Information and Communications Technology, Suita, Japan.
- Graduate School of Frontier Biosciences, Osaka University, Suita, Japan.
| | - Marcello G P Rosa
- Neuroscience Program, Biomedicine Discovery Institute, Monash University, Clayton, VIC, 3800, Australia.
- Department of Physiology, Monash University, Clayton, VIC, 3800, Australia.
- Australian Research Council, Centre of Excellence for Integrative Brain Function, Monash University Node, Melbourne, VIC, 3800, Australia.
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10
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Brown HDH, Gouws AD, Vernon RJW, Lawrence SJD, Donnelly G, Gill L, Gale RP, Baseler HA, Morland AB. Assessing functional reorganization in visual cortex with simulated retinal lesions. Brain Struct Funct 2021; 226:2855-2867. [PMID: 34529124 PMCID: PMC8541975 DOI: 10.1007/s00429-021-02366-w] [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: 03/23/2021] [Accepted: 08/23/2021] [Indexed: 11/07/2022]
Abstract
Macular
degeneration (MD) causes central vision loss, removing input to corresponding representations in the primary visual cortex. There is disagreement concerning whether the cortical regions deprived of input can remain responsive, and the source of reported cortical responses is still debated. To simulate MD in controls, normally sighted participants viewed a bright central disk to adapt the retina, creating a transient ‘retinal lesion’ during a functional MRI experiment. Participants viewed blocks of faces, scrambled faces and uniform grey stimuli, either passively or whilst performing a one-back task. To assess the impact of the simulated lesion, participants repeated the paradigm using a more conventional mean luminance simulated scotoma without adaptation. Our results suggest our attempt to create a more realistic simulation of a lesion did not impact on responses in the representation of the simulated lesion. While most participants showed no evidence of stimulus-driven activation within the lesion representation, a few individuals (22%) exhibited responses similar to a participant with juvenile MD who completed the same paradigm (without adaptation). Reliability analysis showed that responses in the representation of the lesion were generally consistent irrespective of whether positive or negative. We provide some evidence that peripheral visual stimulation can also produce responses in central representations in controls while performing a task. This suggests that the ‘signature of reorganization of visual processing’, is not found solely in patients with retinal lesions, consistent with the idea that activity may be driven by unmasked top–down feedback.
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Affiliation(s)
- Holly D H Brown
- Department of Psychology, University of York, York, UK.,York Neuroimaging Centre, University of York, York, UK.,York Biomedical Research Institute, University of York, York, UK
| | - André D Gouws
- Department of Psychology, University of York, York, UK.,York Neuroimaging Centre, University of York, York, UK
| | - Richard J W Vernon
- Department of Psychology, University of York, York, UK.,York Neuroimaging Centre, University of York, York, UK.,York Biomedical Research Institute, University of York, York, UK
| | - Samuel J D Lawrence
- Department of Psychology, University of York, York, UK.,York Neuroimaging Centre, University of York, York, UK
| | - Gemma Donnelly
- Institute of Neuroscience and Psychology, University of Glasgow, Glasgow, UK
| | - Lorraine Gill
- Department of Psychology, University of York, York, UK
| | - Richard P Gale
- Department of Health Sciences, University of York, York, UK.,Academic Unit of Ophthalmology, York Teaching Hospital NHS Foundation Trust, York, UK
| | - Heidi A Baseler
- Department of Psychology, University of York, York, UK.,York Biomedical Research Institute, University of York, York, UK.,Hull York Medical School, University of York, York, UK
| | - Antony B Morland
- Department of Psychology, University of York, York, UK. .,York Neuroimaging Centre, University of York, York, UK. .,York Biomedical Research Institute, University of York, York, UK.
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11
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Linton P. V1 as an egocentric cognitive map. Neurosci Conscious 2021; 2021:niab017. [PMID: 34532068 PMCID: PMC8439394 DOI: 10.1093/nc/niab017] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Revised: 05/21/2021] [Accepted: 06/08/2021] [Indexed: 01/20/2023] Open
Abstract
We typically distinguish between V1 as an egocentric perceptual map and the hippocampus as an allocentric cognitive map. In this article, we argue that V1 also functions as a post-perceptual egocentric cognitive map. We argue that three well-documented functions of V1, namely (i) the estimation of distance, (ii) the estimation of size, and (iii) multisensory integration, are better understood as post-perceptual cognitive inferences. This argument has two important implications. First, we argue that V1 must function as the neural correlates of the visual perception/cognition distinction and suggest how this can be accommodated by V1's laminar structure. Second, we use this insight to propose a low-level account of visual consciousness in contrast to mid-level accounts (recurrent processing theory; integrated information theory) and higher-level accounts (higher-order thought; global workspace theory). Detection thresholds have been traditionally used to rule out such an approach, but we explain why it is a mistake to equate visibility (and therefore the presence/absence of visual experience) with detection thresholds.
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Affiliation(s)
- Paul Linton
- Centre for Applied Vision Research, City, University of London, Northampton Square, London EC1V 0HB, UK
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12
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Prabhakaran GT, Al-Nosairy KO, Tempelmann C, Wagner M, Thieme H, Hoffmann MB. Functional Dynamics of Deafferented Early Visual Cortex in Glaucoma. Front Neurosci 2021; 15:653632. [PMID: 34381327 PMCID: PMC8350780 DOI: 10.3389/fnins.2021.653632] [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: 01/14/2021] [Accepted: 06/23/2021] [Indexed: 12/03/2022] Open
Abstract
In advanced retinitis pigmentosa with retinal lesions, the lesion projection zone (LPZ) in the early visual cortex can be driven during visual tasks, while it remains unresponsive during passive viewing. We tested whether this finding translates to advanced glaucoma, a major cause of acquired blindness. During visual stimulation, 3T fMRI scans were acquired for participants with advanced glaucoma (n = 4; age range: 51–72) and compared to two reference groups, i.e., advanced retinitis pigmentosa (n = 3; age range: 46–78) and age-matched healthy controls with simulated defects (n = 7). The participants viewed grating patterns drifting in 8 directions (12 s) alternating with uniform gray (12 s), either during passive viewing (PV), i.e., central fixation, or during a one-back task (OBT), i.e., reports of succeeding identical motion directions. As another reference, a fixation-dot task condition was included. Only in glaucoma and retinitis pigmentosa but not in controls, fMRI-responses in the lesion projection zone (LPZ) of V1 shifted from negative for PV to positive for OBT (p = 0.024 and p = 0.012, respectively). In glaucoma, these effects also reached significance in V3 (p = 0.006), while in V2 there was a non-significant trend (p = 0.069). The general absence of positive responses in the LPZ during PV underscores the lack of early visual cortex bottom-up plasticity for acquired visual field defects in humans. Trends in our exploratory analysis suggesting the task-dependent LPZ responses to be inversely related to visual field loss, indicate the benefit of patient stratification strategies in future studies with greater sample sizes. We conclude that top-down mechanisms associated with task-elicited demands rather than visual cortex remapping appear to shape LPZ responses not only in retinitis pigmentosa, but also in glaucoma. These insights are of critical importance for the development of schemes for treatment and rehabilitation in glaucoma and beyond.
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Affiliation(s)
| | | | - Claus Tempelmann
- Department of Neurology, Otto-von-Guericke University, Magdeburg, Germany
| | - Markus Wagner
- Department of Ophthalmology, Otto-von-Guericke University, Magdeburg, Germany
| | - Hagen Thieme
- Department of Ophthalmology, Otto-von-Guericke University, Magdeburg, Germany
| | - Michael B Hoffmann
- Department of Ophthalmology, Otto-von-Guericke University, Magdeburg, Germany.,Center for Behavioral Brain Sciences, Otto-von-Guericke University, Magdeburg, Germany
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Morland AB, Brown HDH, Baseler HA. Cortical Reorganization: Reallocated Responses without Rewiring. Curr Biol 2021; 31:R76-R78. [PMID: 33497635 DOI: 10.1016/j.cub.2020.11.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Is the brain able to reorganise following loss of sensory input? New work on individuals with sight loss shows that, while brain areas normally allocated to vision respond to other sensory stimuli, those responses are unlikely to mean the brain has rewired.
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Affiliation(s)
- Antony B Morland
- Department of Psychology, University of York, York, UK; York Biomedical Research Institute, University of York, York, UK.
| | - Holly D H Brown
- Department of Psychology, University of York, York, UK; York Biomedical Research Institute, University of York, York, UK
| | - Heidi A Baseler
- York Biomedical Research Institute, University of York, York, UK; Hull-York Medical School, York, UK
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