1
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Sperber C, Wiesen D, Karnath H, de Haan B. The neuroanatomy of visual extinction following right hemisphere brain damage: Insights from multivariate and Bayesian lesion analyses in acute stroke. Hum Brain Mapp 2024; 45:e26639. [PMID: 38433712 PMCID: PMC10910281 DOI: 10.1002/hbm.26639] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Revised: 01/08/2024] [Accepted: 02/06/2024] [Indexed: 03/05/2024] Open
Abstract
Multi-target attention, that is, the ability to attend and respond to multiple visual targets presented simultaneously on the horizontal meridian across both visual fields, is essential for everyday real-world behaviour. Given the close link between the neuropsychological deficit of extinction and attentional limits in healthy subjects, investigating the anatomy that underlies extinction is uniquely capable of providing important insights concerning the anatomy critical for normal multi-target attention. Previous studies into the brain areas critical for multi-target attention and its failure in extinction patients have, however, produced heterogeneous results. In the current study, we used multivariate and Bayesian lesion analysis approaches to investigate the anatomical substrate of visual extinction in a large sample of 108 acute right hemisphere stroke patients. The use of acute stroke patient data and multivariate/Bayesian lesion analysis approaches allowed us to address limitations associated with previous studies and so obtain a more complete picture of the functional network associated with visual extinction. Our results demonstrate that the right temporo-parietal junction (TPJ) is critically associated with visual extinction. The Bayesian lesion analysis additionally implicated the right intraparietal sulcus (IPS), in line with the results of studies in neurologically healthy participants that highlighted the IPS as the area critical for multi-target attention. Our findings resolve the seemingly conflicting previous findings, and emphasise the urgent need for further research to clarify the precise cognitive role of the right TPJ in multi-target attention and its failure in extinction patients.
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Affiliation(s)
- Christoph Sperber
- Center of Neurology, Division of NeuropsychologyHertie‐Institute for Clinical Brain Research, University of TübingenTübingenGermany
- Department of NeurologyInselspital, University Hospital BernBernSwitzerland
| | - Daniel Wiesen
- Center of Neurology, Division of NeuropsychologyHertie‐Institute for Clinical Brain Research, University of TübingenTübingenGermany
| | - Hans‐Otto Karnath
- Center of Neurology, Division of NeuropsychologyHertie‐Institute for Clinical Brain Research, University of TübingenTübingenGermany
- Department of PsychologyUniversity of South CarolinaColumbiaSouth CarolinaUSA
| | - Bianca de Haan
- Centre for Cognitive Neuroscience, College of Health and Life Sciences, Brunel University LondonUxbridgeUK
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2
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Cuppini C, Magosso E, Monti M, Ursino M, Yau JM. A neurocomputational analysis of visual bias on bimanual tactile spatial perception during a crossmodal exposure. Front Neural Circuits 2022; 16:933455. [PMID: 36439678 PMCID: PMC9684216 DOI: 10.3389/fncir.2022.933455] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2022] [Accepted: 10/13/2022] [Indexed: 11/11/2022] Open
Abstract
Vision and touch both support spatial information processing. These sensory systems also exhibit highly specific interactions in spatial perception, which may reflect multisensory representations that are learned through visuo-tactile (VT) experiences. Recently, Wani and colleagues reported that task-irrelevant visual cues bias tactile perception, in a brightness-dependent manner, on a task requiring participants to detect unimanual and bimanual cues. Importantly, tactile performance remained spatially biased after VT exposure, even when no visual cues were presented. These effects on bimanual touch conceivably reflect cross-modal learning, but the neural substrates that are changed by VT experience are unclear. We previously described a neural network capable of simulating VT spatial interactions. Here, we exploited this model to test different hypotheses regarding potential network-level changes that may underlie the VT learning effects. Simulation results indicated that VT learning effects are inconsistent with plasticity restricted to unisensory visual and tactile hand representations. Similarly, VT learning effects were also inconsistent with changes restricted to the strength of inter-hemispheric inhibitory interactions. Instead, we found that both the hand representations and the inter-hemispheric inhibitory interactions need to be plastic to fully recapitulate VT learning effects. Our results imply that crossmodal learning of bimanual spatial perception involves multiple changes distributed over a VT processing cortical network.
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Affiliation(s)
- Cristiano Cuppini
- Department of Electrical, Electronic, and Information Engineering “Guglielmo Marconi,” University of Bologna, Bologna, Italy,*Correspondence: Cristiano Cuppini,
| | - Elisa Magosso
- Department of Electrical, Electronic, and Information Engineering “Guglielmo Marconi,” University of Bologna, Bologna, Italy
| | - Melissa Monti
- Department of Electrical, Electronic, and Information Engineering “Guglielmo Marconi,” University of Bologna, Bologna, Italy
| | - Mauro Ursino
- Department of Electrical, Electronic, and Information Engineering “Guglielmo Marconi,” University of Bologna, Bologna, Italy
| | - Jeffrey M. Yau
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, United States
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3
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Barrett AM, Goedert KM, Carter AR, Chaudhari A. Spatial neglect treatment: The brain's spatial-motor Aiming systems. Neuropsychol Rehabil 2022; 32:662-688. [PMID: 33941021 PMCID: PMC9632633 DOI: 10.1080/09602011.2020.1862678] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Accepted: 10/29/2020] [Indexed: 10/21/2022]
Abstract
Animal and human literature supports spatial-motor "Aiming" bias, a frontal-subcortical syndrome, as a core deficit in spatial neglect. However, spatial neglect treatment studies rarely assess Aiming errors. Two knowledge gaps result: spatial neglect rehabilitation studies fail to capture the impact on motor-exploratory aspects of functional disability. Also, across spatial neglect treatment studies, discrepant treatment effects may also result from sampling different proportions of patients with Aiming bias. We review behavioural evidence for Aiming spatial neglect, and demonstrate the importance of measuring and targeting Aiming bias for treatment, by reviewing literature on Aiming spatial neglect and prism adaptation treatment, and presenting new preliminary data on bromocriptine treatment. Finally, we review neuroanatomical and network disruption that may give rise to Aiming spatial neglect. Because Aiming spatial neglect predicts prism adaptation treatment response, assessment may broaden the ability of rehabilitation research to capture functionally-relevant disability. Frontal brain lesions predict both the presence of Aiming spatial neglect, and a robust response to some spatial neglect interventions. Research is needed that co-stratifies spatial neglect patients by lesion location and Aiming spatial neglect, to personalize spatial neglect rehabilitation and perhaps even open a path to spatial retraining as a means of promoting better mobility after stroke.
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Affiliation(s)
- A M Barrett
- Neurorehabilitation Division, Emory Brain Health Center, and Department of Neurology, Emory University School of Medicine, Atlanta, GA, USA
- Center for Visual and Neurocognitive Rehabilitation, Atlanta VA Health System, Decatur, GA, USA
| | - Kelly M Goedert
- Department of Psychology, Seton Hall University, South Orange, NJ, USA
| | - Alexandre R Carter
- Neurorehabilitation Division, Department of Neurology, Washington University School of Medicine, Saint Louis, MO, USA
- Program in Occupational Therapy, Washington University in Saint Louis, Saint Louis, MO, USA
| | - Amit Chaudhari
- Department of Neurology, University of California Irvine, Irvine, CA, USA
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4
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Salvato G, Peviani V, Scarpa P, Francione S, Castana L, Gallace A, Bricolo E, Vallar G, Bottini G. Investigating visuo-spatial neglect and visual extinction during intracranial electrical stimulations: The role of the right inferior parietal cortex. Neuropsychologia 2021; 162:108049. [PMID: 34624258 DOI: 10.1016/j.neuropsychologia.2021.108049] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Revised: 08/09/2021] [Accepted: 10/04/2021] [Indexed: 11/28/2022]
Abstract
Both visuo-spatial neglect and visual extinction may occur following right-brain damage. So far, studies on brain-damaged patients have not provided definite evidence about which lesion patterns may lead to the association or dissociation of these deficits. This study was set out to address this issue using Intracranial Electrical Stimulation (IES) in a group of nine patients affected by refractory epilepsy. Cerebral regions associated with visuo-spatial neglect and visual extinction were stimulated, including the right frontal, temporal, and posterior parietal areas. During IES, patients with intracranial implantation involving at least one of these cortical regions were administered with a manual line bisection task (N = 9) to assess visuo-spatial neglect, and a computerized task (N = 8) assessing visual extinction. Results showed that parietal IES induced a rightward bias at the manual bisection task, together with a general improvement in reaction times at bilateral and unilateral visual stimuli detection at the extinction task. The occurrence of visual extinction did not vary across stimulations. By adopting a complementary approach to anatomo-clinical correlation studies, our work corroborates the notion that lesions to the right inferior parietal lobule play a pivotal role in the pathogenesis of visuo-spatial neglect. Importantly, our results also suggest that temporarily interfering with the activity of this region is not sufficient per se to generate visual extinction, which instead may involve a broader and/or different network, possibly extending beyond the cerebral regions considered here, posing important theoretical and clinical implications.
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Affiliation(s)
- Gerardo Salvato
- Department of Brain and Behavioral Sciences, University of Pavia, Pavia, Italy; Centre of Cognitive Neuropsychology, ASST "Grande Ospedale Metropolitano", Niguarda Hospital, Milano, Italy; NeuroMI, Milan Center for Neuroscience, Milano, Italy
| | - Valeria Peviani
- Department of Brain and Behavioral Sciences, University of Pavia, Pavia, Italy; Department of Neuroscience, Max Planck Institute for Empirical Aesthetics, Frankfurt Am Main, Germany
| | - Pina Scarpa
- Centre of Cognitive Neuropsychology, ASST "Grande Ospedale Metropolitano", Niguarda Hospital, Milano, Italy; NeuroMI, Milan Center for Neuroscience, Milano, Italy
| | - Stefano Francione
- "Claudio Munari" Center for Epilepsy Surgery, ASST "Grande Ospedale Metropolitano", Niguarda Hospital, Milano, Italy
| | - Laura Castana
- "Claudio Munari" Center for Epilepsy Surgery, ASST "Grande Ospedale Metropolitano", Niguarda Hospital, Milano, Italy
| | - Alberto Gallace
- NeuroMI, Milan Center for Neuroscience, Milano, Italy; Department of Psychology, University of Milano-Bicocca, Milano, Italy
| | - Emanuela Bricolo
- NeuroMI, Milan Center for Neuroscience, Milano, Italy; Department of Psychology, University of Milano-Bicocca, Milano, Italy
| | - Giuseppe Vallar
- NeuroMI, Milan Center for Neuroscience, Milano, Italy; Department of Psychology, University of Milano-Bicocca, Milano, Italy; Neuropsychological Laboratory, IRCCS Istituto Auxologico Italiano, Italy
| | - Gabriella Bottini
- Department of Brain and Behavioral Sciences, University of Pavia, Pavia, Italy; Centre of Cognitive Neuropsychology, ASST "Grande Ospedale Metropolitano", Niguarda Hospital, Milano, Italy; NeuroMI, Milan Center for Neuroscience, Milano, Italy.
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5
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Asymmetrical Pseudo-Extinction Phenomenon in the Illusory Line Motion. Symmetry (Basel) 2020. [DOI: 10.3390/sym12081322] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Illusory Line Motion (i.e., a static line, presented after a lateral cue, is perceived as movement in the opposite direction to the cue) has been used to study a phenomenon of perceptual asymmetry. We have demonstrated the presence of an illusion of leftward movement, even in the presence of bilateral symmetrical cues. We have classified this phenomenon as one of pseudo-extinction. The paradigm of the four experiments performed was always the same: a white line, briefly presented alone or preceded by one or two lateral cues (150 ms), was judged by a group of young participants to be moving either to one side or the other. The asymmetrical effect in the bilateral cue condition was observed with horizontal lines (Experiment 1 and 4), and not with vertical or oblique (Experiment 2 and 3). These results suggest that the effect is linked to the asymmetry of the horizontal spatial planum and the mechanisms of spatial attention. Experiment 4 verified whether the Illusory Line Motion involves the collicular pathway by using blue stimuli for the cues, which activate less the Superior Colliculus (SC), with negative results. We interpreted the asymmetrical pseudo-extinction phenomenon in terms of a right-space exogenous attention advantage.
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6
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Abdou A, Pilkar R, Chen P, Yue G, Barrett A. Improved stability of long-duration sitting in spatial neglect after a single session of prism adaptation. Neurocase 2020; 26:201-210. [PMID: 32600098 DOI: 10.1080/13554794.2020.1786134] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Spatial neglect after right brain stroke affects balance, and improvements in sitting balance after prism adaptation have been demonstrated using short-duration center of pressure (CoP) data. We present long-duration (5 min) CoP and trunk muscles electromyography recordings of a 61-year-old man with left-sided spatial neglect, before and after a single session of prism adaptation. His CoP-derived measures showed improved balance and postural stability in both the anterior-posterior and medial-lateral directions after prism adaptation. Concurrently, asymmetry in neuromuscular activations was reduced. The findings suggest that improved sitting balance may be associated with more symmetrical activation of trunk muscles after prism adaptation.
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Affiliation(s)
- Andrew Abdou
- Burke Rehabilitation Hospital , White Plains, NY, USA.,Department of Physical Medicine & Rehabilitation, Montefiore Medical Center , Bronx, NY, USA.,The Arthur S. Abramson Department of Rehabilitation Medicine, Albert Einstein College of Medicine , Bronx, NY, USA
| | - Rakesh Pilkar
- Center for Mobility and Rehabilitation Engineering Research, Kessler Foundation , West Orange, NJ, USA.,eDepartment of Physical Medicine & Rehabilitation, Rutgers - New Jersey Medical School , Newark, NJ, USA
| | - Peii Chen
- eDepartment of Physical Medicine & Rehabilitation, Rutgers - New Jersey Medical School , Newark, NJ, USA.,Center for Stroke Rehabilitation Research, Kessler Foundation , West Orange, NJ, USA
| | - Guang Yue
- Center for Mobility and Rehabilitation Engineering Research, Kessler Foundation , West Orange, NJ, USA.,eDepartment of Physical Medicine & Rehabilitation, Rutgers - New Jersey Medical School , Newark, NJ, USA
| | - A Barrett
- Department of Neurology, Emory School of Medicine , Atlanta, GA, USA.,Center for Visual and Neurocognitive Rehabilitation, Atlanta VA Medical Center , Decatur, GA, USA
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7
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Beume LA, Rijntjes M, Dressing A, Kaller CP, Hieber M, Martin M, Kirsch S, Kümmerer D, Urbach H, Umarova RM, Weiller C. Dissociation of visual extinction and neglect in the left hemisphere. Cortex 2020; 129:211-222. [PMID: 32505793 DOI: 10.1016/j.cortex.2020.04.010] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Revised: 04/05/2020] [Accepted: 04/06/2020] [Indexed: 11/27/2022]
Abstract
Visual neglect and extinction are two distinct visuospatial attention deficits that frequently occur after right hemisphere cerebral stroke. However, their different lesion profiles remain a matter of debate. In the left hemisphere, a domain-general dual-loop model with distinct computational abilities onto which several cognitive functions may project, has been proposed: a dorsal stream for sensori-motor mapping in time and space and a ventral stream for comprehension and representation of concepts. We wondered whether such a distinction may apply to visual extinction and neglect in left hemisphere lesions. Of 165 prospectively studied patients with acute left hemispheric ischemic stroke with a single lesion on MRI, 122 had no visuospatial attention deficit, 10 had extinction, 31 neglect and 2 had both, visual extinction and neglect. Voxel-based-lesion-symptom mapping (VLSM, FDR<.05) showed a clear anatomical dissociation. Extinction occurred after damage to the parietal cortex (anterior bank of the intraparietal sulcus, inferior parietal lobe, and supramarginal gyrus), while visual neglect occurred after damage mainly to the temporal lobe (superior and middle temporal lobe, anterior temporal pole), inferior ventral premotor cortex, frontal operculum, angular gyrus, and insula. Direct comparison of both conditions linked extinction to intraparietal sulcus and supramarginal gyrus (FDR<.05). Thus, in the left hemisphere extinction seems to be related to dorsal stream lesions, whereas neglect maps more on the ventral stream. These data cannot be generalized to the right hemisphere. However, a domain-general point-of-view may stimulate discussion on visuospatial attention processing also in the right hemisphere.
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Affiliation(s)
- Lena-Alexandra Beume
- Department of Neurology and Neuroscience, University Medical Center Freiburg, Freiburg, Germany; Freiburg Brain Imaging Center, University Medical Center Freiburg, Freiburg, Germany; BrainLinks-BrainTools Cluster of Excellence, University Medical Center Freiburg, Freiburg, Germany
| | - Michel Rijntjes
- Department of Neurology and Neuroscience, University Medical Center Freiburg, Freiburg, Germany; Freiburg Brain Imaging Center, University Medical Center Freiburg, Freiburg, Germany; BrainLinks-BrainTools Cluster of Excellence, University Medical Center Freiburg, Freiburg, Germany
| | - Andrea Dressing
- Department of Neurology and Neuroscience, University Medical Center Freiburg, Freiburg, Germany; Freiburg Brain Imaging Center, University Medical Center Freiburg, Freiburg, Germany; BrainLinks-BrainTools Cluster of Excellence, University Medical Center Freiburg, Freiburg, Germany
| | - Christoph P Kaller
- Department of Neurology and Neuroscience, University Medical Center Freiburg, Freiburg, Germany; Freiburg Brain Imaging Center, University Medical Center Freiburg, Freiburg, Germany; BrainLinks-BrainTools Cluster of Excellence, University Medical Center Freiburg, Freiburg, Germany
| | - Maren Hieber
- Department of Neurology and Neuroscience, University Medical Center Freiburg, Freiburg, Germany; Freiburg Brain Imaging Center, University Medical Center Freiburg, Freiburg, Germany; BrainLinks-BrainTools Cluster of Excellence, University Medical Center Freiburg, Freiburg, Germany
| | - Markus Martin
- Department of Neurology and Neuroscience, University Medical Center Freiburg, Freiburg, Germany; Freiburg Brain Imaging Center, University Medical Center Freiburg, Freiburg, Germany; BrainLinks-BrainTools Cluster of Excellence, University Medical Center Freiburg, Freiburg, Germany
| | - Simon Kirsch
- Department of Neurology and Neuroscience, University Medical Center Freiburg, Freiburg, Germany; Freiburg Brain Imaging Center, University Medical Center Freiburg, Freiburg, Germany
| | - Dorothee Kümmerer
- Department of Neurology and Neuroscience, University Medical Center Freiburg, Freiburg, Germany; Freiburg Brain Imaging Center, University Medical Center Freiburg, Freiburg, Germany; BrainLinks-BrainTools Cluster of Excellence, University Medical Center Freiburg, Freiburg, Germany
| | - Horst Urbach
- Freiburg Brain Imaging Center, University Medical Center Freiburg, Freiburg, Germany; Department of Neuroradiology, University Medical Center Freiburg, Freiburg, Germany
| | - Roza M Umarova
- Department of Neurology and Neuroscience, University Medical Center Freiburg, Freiburg, Germany; Freiburg Brain Imaging Center, University Medical Center Freiburg, Freiburg, Germany; BrainLinks-BrainTools Cluster of Excellence, University Medical Center Freiburg, Freiburg, Germany; Department of Neurology, Inselspital, Bern University Hospital, University of Bern, Switzerland
| | - Cornelius Weiller
- Department of Neurology and Neuroscience, University Medical Center Freiburg, Freiburg, Germany; Freiburg Brain Imaging Center, University Medical Center Freiburg, Freiburg, Germany; BrainLinks-BrainTools Cluster of Excellence, University Medical Center Freiburg, Freiburg, Germany.
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8
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Goedert KM, Chen P, Foundas AL, Barrett A. Frontal lesions predict response to prism adaptation treatment in spatial neglect: A randomised controlled study. Neuropsychol Rehabil 2020; 30:32-53. [PMID: 29558241 PMCID: PMC6148387 DOI: 10.1080/09602011.2018.1448287] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Accepted: 02/28/2018] [Indexed: 10/17/2022]
Abstract
Spatial neglect commonly follows right hemisphere stroke. It is defined as impaired contralesional stimulus detection, response, or action, causing functional disability. While prism adaptation treatment is highly promising to promote functional recovery of spatial neglect, not all individuals respond. Consistent with a primary effect of prism adaptation on spatial movements, we previously demonstrated that functional improvement after prism adaptation treatment is linked to frontal lobe lesions. However, that study was a treatment-only study with no randomised control group. The current study randomised individuals with spatial neglect to receive 10 days of prism adaptation treatment or to receive only standard care (control group). Replicating our earlier results, we found that the presence of frontal lesions moderated response to prism adaptation treatment: among prism-treated patients, only those with frontal lesions demonstrated functional improvements in their neglect symptoms. Conversely, among individuals in the standard care control group, the presence of frontal lesions did not modify recovery. These results suggest that further research is needed on how frontal lesions may predict response to prism adaptation treatment. Additionally, the results help elucidate the neural network involved in spatial movement and could be used to aid decisions about treatment.
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Affiliation(s)
- Kelly M. Goedert
- Department of Psychology, Seton Hall University, 400 South Orange Ave., South Orange, NJ 07079, phone: 1-973-275-2703;
| | - Peii Chen
- Stroke Rehabilitation Research, Kessler Foundation, Department of Physical Medicine and Rehabilitation, Rutgers- New Jersey Medical School, 1199 Pleasant Valley Way, West Orange, NJ 07052, phone: 1-973-324-2574;
| | - Anne L. Foundas
- Department of Psychology, Tulane University, 2007 Percival Stern Hall, New Orleans, Louisiana 70118, phone: (504) 865-5331,
| | - A.M. Barrett
- Stroke Rehabilitation Research, Kessler Foundation, Department of Physical Medicine and Rehabilitation, Rutgers-New Jersey Medical School, Kessler Institute for Rehabilitation, 1199 Pleasant Valley Way, West Orange, NJ 07052, phone: 1-973-324-3569;
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9
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Verfaille C, Filbrich L, Cordova Bulens D, Lefèvre P, Berquin A, Barbier O, Libouton X, Fraselle V, Mouraux D, Legrain V. Robot-assisted line bisection in patients with Complex Regional Pain Syndrome. PLoS One 2019; 14:e0213732. [PMID: 31048861 PMCID: PMC6497371 DOI: 10.1371/journal.pone.0213732] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2018] [Accepted: 02/27/2019] [Indexed: 11/18/2022] Open
Abstract
Complex Regional Pain Syndrome (CRPS) is characterized by pain, motor and inflammatory symptoms usually affecting one limb. Cognitive difficulties have been reported to affect patients’ ability to represent, perceive and use their affected limb. It is debated whether these difficulties result from deficits in controlling goal-directed movements in space or from a learned strategy to protect the affected limb. In order to dissociate the two hypotheses, patients with upper-limb CRPS were asked to move with their unaffected hand towards visual targets projected at different positions on a horizontal semi-reflexive mirror. By means of a robotic handle placed below the screen, they were asked to move a cursor, to reach and cross lines at their estimated midpoint. In some of the stimulation series, the affected hand was placed below the mirror so that some lines appeared projected onto that hand. Vision of the hands and the robotic handle was preserved or prevented by opening or closing a shutter below the mirror. Lines were displayed on the mirror according to which part of the body was affected (ispi- vs. contralateral) and the actual position of the affected hand (inside vs. outside the workspace). Comparatively to control participants, CRPS patients generally biased their estimation by bisecting the lines towards their left side, irrelative of which part of the body was affected and the position of the affected hand, both in ipsi- and contralateral space, with only a few exceptions. Our results are in line with previous studies having described a visuospatial deficit in CRPS patients and discard the explanation of observed symptoms in terms of learned nonuse strategies, as only the unaffected hand was used to perform the task. It is suggested that CRPS patients can display difficulties to perform tasks requesting visuo-motor coordination, reflecting the complex cortical reorganization occurring in CRPS.
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Affiliation(s)
- Charlotte Verfaille
- Institute of Neuroscience, Université catholique de Louvain, Brussels, Belgium
- * E-mail:
| | - Lieve Filbrich
- Institute of Neuroscience, Université catholique de Louvain, Brussels, Belgium
- Psychological Sciences Research Institute, Université catholique de Louvain, Louvain-la-Neuve, Belgium
| | - David Cordova Bulens
- Institute of Neuroscience, Université catholique de Louvain, Brussels, Belgium
- Institute of Information and Communication Technologies, Electronics and Applied Mathematics, Louvain-la-Neuve, Belgium
| | - Philippe Lefèvre
- Institute of Neuroscience, Université catholique de Louvain, Brussels, Belgium
- Institute of Information and Communication Technologies, Electronics and Applied Mathematics, Louvain-la-Neuve, Belgium
| | - Anne Berquin
- Institute of Neuroscience, Université catholique de Louvain, Brussels, Belgium
- Saint-Luc University Hospital, Brussels, Belgium
| | - Olivier Barbier
- Saint-Luc University Hospital, Brussels, Belgium
- Institute of Experimental and Clinical Research, Université catholique de Louvain, Brussels, Belgium
| | - Xavier Libouton
- Saint-Luc University Hospital, Brussels, Belgium
- Institute of Experimental and Clinical Research, Université catholique de Louvain, Brussels, Belgium
| | - Virginie Fraselle
- Saint-Luc University Hospital, Brussels, Belgium
- Faculty of Motor Sciences, Université catholique de Louvain, Louvain-la-Neuve, Belgium
| | - Dominique Mouraux
- Faculty of Motor Sciences, Université libre de Bruxelles, Brussels, Belgium
- Erasme University Hospital, Brussels, Belgium
| | - Valéry Legrain
- Institute of Neuroscience, Université catholique de Louvain, Brussels, Belgium
- Psychological Sciences Research Institute, Université catholique de Louvain, Louvain-la-Neuve, Belgium
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10
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Barrett A, Abdou A, Caulfield MD. The cingulate cortex and spatial neglect. HANDBOOK OF CLINICAL NEUROLOGY 2019; 166:129-150. [DOI: 10.1016/b978-0-444-64196-0.00009-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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11
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Cuppini C, Shams L, Magosso E, Ursino M. A biologically inspired neurocomputational model for audiovisual integration and causal inference. Eur J Neurosci 2018; 46:2481-2498. [PMID: 28949035 DOI: 10.1111/ejn.13725] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2016] [Revised: 09/18/2017] [Accepted: 09/19/2017] [Indexed: 11/28/2022]
Abstract
Recently, experimental and theoretical research has focused on the brain's abilities to extract information from a noisy sensory environment and how cross-modal inputs are processed to solve the causal inference problem to provide the best estimate of external events. Despite the empirical evidence suggesting that the nervous system uses a statistically optimal and probabilistic approach in addressing these problems, little is known about the brain's architecture needed to implement these computations. The aim of this work was to realize a mathematical model, based on physiologically plausible hypotheses, to analyze the neural mechanisms underlying multisensory perception and causal inference. The model consists of three layers topologically organized: two encode auditory and visual stimuli, separately, and are reciprocally connected via excitatory synapses and send excitatory connections to the third downstream layer. This synaptic organization realizes two mechanisms of cross-modal interactions: the first is responsible for the sensory representation of the external stimuli, while the second solves the causal inference problem. We tested the network by comparing its results to behavioral data reported in the literature. Among others, the network can account for the ventriloquism illusion, the pattern of sensory bias and the percept of unity as a function of the spatial auditory-visual distance, and the dependence of the auditory error on the causal inference. Finally, simulations results are consistent with probability matching as the perceptual strategy used in auditory-visual spatial localization tasks, agreeing with the behavioral data. The model makes untested predictions that can be investigated in future behavioral experiments.
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Affiliation(s)
- Cristiano Cuppini
- Department of Electrical, Electronic and Information Engineering, University of Bologna, Viale Risorgimento 2, I40136, Bologna, Italy
| | - Ladan Shams
- Department of Psychology, Department of BioEngineering, Interdepartmental Neuroscience Program, University of California, Los Angeles, CA, USA
| | - Elisa Magosso
- Department of Electrical, Electronic and Information Engineering, University of Bologna, Viale Risorgimento 2, I40136, Bologna, Italy
| | - Mauro Ursino
- Department of Electrical, Electronic and Information Engineering, University of Bologna, Viale Risorgimento 2, I40136, Bologna, Italy
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12
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Wright A, Saxena S, Sheppard SM, Hillis AE. Selective impairments in components of affective prosody in neurologically impaired individuals. Brain Cogn 2018; 124:29-36. [PMID: 29723680 DOI: 10.1016/j.bandc.2018.04.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2018] [Revised: 04/13/2018] [Accepted: 04/15/2018] [Indexed: 11/30/2022]
Abstract
The intent and feelings of the speaker are often conveyed less by what they say than by how they say it, in terms of the affective prosody - modulations in pitch, loudness, rate, and rhythm of the speech to convey emotion. Here we propose a cognitive architecture of the perceptual, cognitive, and motor processes underlying recognition and generation of affective prosody. We developed the architecture on the basis of the computational demands of the task, and obtained evidence for various components by identifying neurologically impaired patients with relatively specific deficits in one component. We report analysis of performance across tasks of recognizing and producing affective prosody by four patients (three with right hemisphere stroke and one with frontotemporal dementia). Their distinct patterns of performance across tasks and quality of their abnormal performance provides preliminary evidence that some of the components of the proposed architecture can be selectively impaired by focal brain damage.
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Affiliation(s)
- Amy Wright
- Johns Hopkins University School of Medicine, Department of Neurology, USA
| | - Sadhvi Saxena
- Johns Hopkins University School of Medicine, Department of Neurology, USA
| | - Shannon M Sheppard
- Johns Hopkins University School of Medicine, Department of Neurology, USA
| | - Argye E Hillis
- Johns Hopkins University School of Medicine, Department of Neurology, USA; Johns Hopkins University School of Medicine, Department of Physical and Medicine & Rehabilitation, USA; Johns Hopkins University, Department of Cognitive Science, USA.
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13
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Extinction as a deficit of the decision-making circuitry in the posterior parietal cortex. HANDBOOK OF CLINICAL NEUROLOGY 2018. [PMID: 29519457 DOI: 10.1016/b978-0-444-63622-5.00008-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register]
Abstract
Extinction is a common neurologic deficit that often occurs as one of a constellation of symptoms seen with lesions of the posterior parietal cortex (PPC). Although extinction has typically been considered a deficit in the allocation of attention, new findings, particularly from nonhuman primate studies, point to one potential and important source of extinction as damage to decision-making circuits for actions within the PPC. This new understanding provides clues to potential therapies for extinction. Also the finding that the PPC is important for action decisions and action planning has led to new neuroprosthetic applications using PPC recordings as control signals to assist paralyzed patients.
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14
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Adapting the concepts of brain and cognitive reserve to post-stroke cognitive deficits: Implications for understanding neglect. Cortex 2017; 97:327-338. [DOI: 10.1016/j.cortex.2016.12.006] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2016] [Revised: 08/03/2016] [Accepted: 12/04/2016] [Indexed: 01/17/2023]
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15
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Goedert KM, Zhang JY, Barrett AM. Prism adaptation and spatial neglect: the need for dose-finding studies. Front Hum Neurosci 2015; 9:243. [PMID: 25983688 PMCID: PMC4415396 DOI: 10.3389/fnhum.2015.00243] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2015] [Accepted: 04/14/2015] [Indexed: 12/29/2022] Open
Abstract
Spatial neglect is a devastating disorder in 50–70% of right-brain stroke survivors, who have problems attending to, or making movements towards, left-sided stimuli, and experience a high risk of chronic dependence. Prism adaptation is a promising treatment for neglect that involves brief, daily visuo-motor training sessions while wearing optical prisms. Its benefits extend to functional behaviors such as dressing, with effects lasting 6 months or longer. Because one to two sessions of prism adaptation induce adaptive changes in both spatial-motor behavior (Fortis et al., 2011) and brain function (Saj et al., 2013), it is possible stroke patients may benefit from treatment periods shorter than the standard, intensive protocol of ten sessions over two weeks—a protocol that is impractical for either US inpatient or outpatient rehabilitation. Demonstrating the effectiveness of a lower dose will maximize the availability of neglect treatment. We present preliminary data suggesting that four to six sessions of prism treatment may induce a large treatment effect, maintained three to four weeks post-treatment. We call for a systematic, randomized clinical trial to establish the minimal effective dose suitable for stroke intervention.
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Affiliation(s)
- Kelly M Goedert
- Department of Psychology, Seton Hall University South Orange, NJ, USA
| | | | - A M Barrett
- Stroke Rehabilitation Research, Kessler Foundation West Orange, NJ, USA ; Department of Neurology and Neurosciences, Rutgers-New Jersey Medical School Newark, NJ, USA ; Department of Physical Medicine and Rehabilitation, Rutgers-New Jersey Medical School Newark, NJ, USA
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16
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Chechlacz M, Rotshtein P, Demeyere N, Bickerton WL, Humphreys GW. The frequency and severity of extinction after stroke affecting different vascular territories. Neuropsychologia 2013; 54:11-7. [PMID: 24378715 DOI: 10.1016/j.neuropsychologia.2013.12.016] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2013] [Revised: 12/12/2013] [Accepted: 12/18/2013] [Indexed: 10/25/2022]
Abstract
We examined the frequency and severity of visual versus tactile extinction based on data from a large group of sub-acute patients (n=454) with strokes affecting different vascular territories. After right hemisphere damage visual and tactile extinction were equally common. However, after left hemisphere damage tactile extinction was more common than visual. The frequency of extinction was significantly higher in patients with right compared to left hemisphere damage in both visual and tactile modalities but this held only for strokes affecting the MCA and PCA territories and not for strokes affecting other vascular territories. Furthermore, the severity of extinction did not differ as a function of either the stimulus modality (visual versus tactile), the affected hemisphere (left versus right) or the stroke territory (MCA, PCA or other vascular territories). We conclude that the frequency but not severity of extinction in both modalities relates to the side of damage (i.e. left versus right hemisphere) and the vascular territories affected by the stroke, and that left hemisphere dominance for motor control may link to the greater incidence of tactile than visual extinction after left hemisphere stroke. We discuss the implications of our findings for understanding hemispheric lateralization within visuospatial attention networks.
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Affiliation(s)
- Magdalena Chechlacz
- Department of Experimental Psychology, Oxford University, 9 South Parks Road, Oxford OX1 3UD, UK.
| | - Pia Rotshtein
- Behavioural Brain Sciences Centre, School of Psychology, University of Birmingham, Birmingham B15 2 TT, UK
| | - Nele Demeyere
- Department of Experimental Psychology, Oxford University, 9 South Parks Road, Oxford OX1 3UD, UK
| | - Wai-Ling Bickerton
- Behavioural Brain Sciences Centre, School of Psychology, University of Birmingham, Birmingham B15 2 TT, UK
| | - Glyn W Humphreys
- Department of Experimental Psychology, Oxford University, 9 South Parks Road, Oxford OX1 3UD, UK
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17
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Goedert KM, Chen P, Boston RC, Foundas AL, Barrett AM. Presence of Motor-Intentional Aiming Deficit Predicts Functional Improvement of Spatial Neglect With Prism Adaptation. Neurorehabil Neural Repair 2013; 28:483-93. [PMID: 24376064 DOI: 10.1177/1545968313516872] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
UNLABELLED Background Spatial neglect is a debilitating disorder for which there is no agreed on course of rehabilitation. The lack of consensus on treatment may result from systematic differences in the syndrome's characteristics, with spatial cognitive deficits potentially affecting perceptual-attentional "Where" or motor-intentional "Aiming" spatial processing. Heterogeneity of response to treatment might be explained by different treatment impacts on these dissociated deficits: prism adaptation, for example, might reduce Aiming deficits without affecting Where spatial deficits. OBJECTIVE Here, we tested the hypothesis that classifying patients by their profile of Where-versus-Aiming spatial deficit would predict response to prism adaptation and specifically that patients with Aiming bias would have better recovery than those with isolated Where bias. Methods We classified the spatial errors of 24 subacute right stroke survivors with left spatial neglect as (1) isolated Where bias, (2) isolated Aiming bias, or (3) both. Participants then completed 2 weeks of prism adaptation treatment. They also completed the Behavioral Inattention Test and Catherine Bergego Scale (CBS) tests of neglect recovery weekly for 6 weeks. Results As hypothesized, participants with only Aiming deficits improved on the CBS, whereas those with only Where deficits did not improve. Participants with both deficits demonstrated intermediate improvement. Conclusion These results support behavioral classification of spatial neglect patients as a potential valuable tool for assigning targeted, effective early rehabilitation.
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Affiliation(s)
| | - Peii Chen
- Kessler Foundation, West Orange, NJ, USA Rutgers New Jersey Medical School, Newark, NJ, USA
| | | | | | - A M Barrett
- Kessler Foundation, West Orange, NJ, USA Rutgers New Jersey Medical School, Newark, NJ, USA Kessler Institute for Rehabilitation, West Orange, NJ, USA
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18
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Vuilleumier P. Mapping the functional neuroanatomy of spatial neglect and human parietal lobe functions: progress and challenges. Ann N Y Acad Sci 2013; 1296:50-74. [PMID: 23751037 DOI: 10.1111/nyas.12161] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Spatial neglect is generally defined by various deficits in processing information from one (e.g., left) side of space contralateral to focal (e.g., right) hemisphere damage. Although classically associated with parietal lobe functions, there is now compelling evidence that neglect can follow lesions in many different cortical and subcortical sites, suggesting a dysfunction in distributed brain networks. In addition, neglect is likely to result from a combination of distinct deficits that co-occur due to concomitant damage affecting juxtaposed brain areas and their connections, but the exact nature of core deficits and their neural substrates still remains unclear. The present review describes recent progress in identifying functional components of the neglect syndrome and relating them to distinct subregions of parietal cortex. A comprehensive understanding of spatial neglect will require a more precise definition of cognitive processes implicated in different behavioral manifestations, as well as meticulous mapping of these processes onto specific brain circuits, while taking into account functional changes in activity that may arise in structurally intact areas subsequent to damage in distant portions of the relevant networks.
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Affiliation(s)
- Patrik Vuilleumier
- Laboratory for Behavioral Neurology and Imaging of Cognition, Department of Neuroscience, Medical School, and University Hospital of Geneva, University of Geneva, Michel-Servet 1, Geneva, Switzerland.
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Urner M, Sarri M, Grahn J, Manly T, Rees G, Friston K. The role of prestimulus activity in visual extinction. Neuropsychologia 2013; 51:1630-7. [PMID: 23680398 PMCID: PMC3702998 DOI: 10.1016/j.neuropsychologia.2013.05.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2012] [Revised: 05/02/2013] [Accepted: 05/06/2013] [Indexed: 11/23/2022]
Abstract
Patients with visual extinction following right-hemisphere damage sometimes see and sometimes miss stimuli in the left visual field, particularly when stimuli are presented simultaneously to both visual fields. Awareness of left visual field stimuli is associated with increased activity in bilateral parietal and frontal cortex. However, it is unknown why patients see or miss these stimuli. Previous neuroimaging studies in healthy adults show that prestimulus activity biases perceptual decisions, and biases in visual perception can be attributed to fluctuations in prestimulus activity in task relevant brain regions. Here, we used functional MRI to investigate whether prestimulus activity affected perception in the context of visual extinction following stroke. We measured prestimulus activity in stimulus-responsive cortical areas during an extinction paradigm in a patient with unilateral right parietal damage and visual extinction. This allowed us to compare prestimulus activity on physically identical bilateral trials that either did or did not lead to visual extinction. We found significantly increased activity prior to stimulus presentation in two areas that were also activated by visual stimulation: the left calcarine sulcus and right occipital inferior cortex. Using dynamic causal modelling (DCM) we found that both these differences in prestimulus activity and stimulus evoked responses could be explained by enhanced effective connectivity within and between visual areas, prior to stimulus presentation. Thus, we provide evidence for the idea that differences in ongoing neural activity in visually responsive areas prior to stimulus onset affect awareness in visual extinction, and that these differences are mediated by fluctuations in extrinsic and intrinsic connectivity. Prestimulus activity in visual extinction affects perception. The BOLD signal in two visual areas is indicative of perception in bilateral trials. Intrinsic and extrinsic connectivity is elevated prior to perceived trials.
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Affiliation(s)
- Maren Urner
- UCL Institute of Cognitive Neuroscience, London WC1N 3AR, UK.
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20
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Common and distinct neural mechanisms of visual and tactile extinction: A large scale VBM study in sub-acute stroke. NEUROIMAGE-CLINICAL 2013; 2:291-302. [PMID: 24179784 PMCID: PMC3777674 DOI: 10.1016/j.nicl.2013.01.013] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/31/2012] [Revised: 01/30/2013] [Accepted: 01/31/2013] [Indexed: 11/27/2022]
Abstract
Extinction is diagnosed when patients respond to a single contralesional item but fail to detect this item when an ipsilesional item is present concurrently. Extinction has been studied mainly in the visual modality but it occurs also in other sensory modalities (touch, audition) and hence can be considered a multisensory phenomenon. The functional and neuroanatomical relations between extinction in different modalities are poorly understood. Here, we used voxel-based mophometry (VBM) to examine the neuronal substrates of visual versus tactile extinction in a large group of sub-acute patients (n = 454) with strokes affecting different vascular territories. We found that extinction deficits in tactile and visual modalities were significantly correlated (r = 0.341; p < 0.01). Several lesions within the right hemisphere were linked to extinction including the inferior parietal lobule, the superior parietal lobule, the middle frontal and occipital gyri, while lesions involving the superior temporal gyrus, inferior temporal gyrus and putamen were associated with tactile extinction. Damage within the middle temporal gyrus and superior temporal sulcus was linked to both deficits. We conclude that extinction in different modalities emerges after damage to both common (supra-modal) and distinct (modality specific) brain regions, and that contrasting sites emerge after damage to different vascular territories. We discuss the implications for understanding extinction as a multisensory disorder.
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21
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Chechlacz M, Rotshtein P, Hansen PC, Deb S, Riddoch MJ, Humphreys GW. The central role of the temporo-parietal junction and the superior longitudinal fasciculus in supporting multi-item competition: Evidence from lesion-symptom mapping of extinction. Cortex 2013; 49:487-506. [DOI: 10.1016/j.cortex.2011.11.008] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2010] [Revised: 05/13/2011] [Accepted: 11/16/2011] [Indexed: 11/28/2022]
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Abstract
Spatial neglect is a frequent cause of disability associated with high costs and duration of hospital stay, increased family burden, and requirements for skilled chronic care. This condition is disproportionately more frequent with right than left hemispheric injury and it is characterized by perceptual, representational, and behavioral deficits involving or directed towards the left hemispace or the left hemibody. Spatial dysfunction is conceptualized into two major components: the perceptual/representational "where" component that results mainly from injury to posterior brain regions and the premotor/intentional "aiming" component that results mostly from damage to anterior brain regions. Additionally, deficits in arousal, vigilance, affective symptoms, and disorders of emotional communication may compound the clinical manifestations of spatial neglect. Evidence-based sources that evaluate the effectiveness of rehabilitation treatments for neglect are, unfortunately, unable to provide a unified consensus for the efficacy of a given treatment approach. The reasons for this failure are related to internal inconsistencies defining appropriate criteria for treatment success and lack of characterization of neglect mechanisms and considerations of patient characteristics related to treatment failure. In this chapter we advocate the use of visual scanning, limb activation therapy, and "general treatment" because we believe that they are appropriately supported by different sources and they may be useful for experimental trials and standardized clinical care. We advocate an integrative approach that takes advantage of the same rehabilitation strategy or task to treat different perceptual, representational, and premotor components of neglect. A variety of therapies that may be familiar to the rehabilitation team may be useful as long as they are applied in a systematized program and are based on good clinical judgment. Information regarding adjuvant pharmacological therapy is sparse but different agents with aminergic and cholinergic activity may be useful. Medication with sedative, antidopaminergic or anticholinergic properties may interfere with the rehabilitation process and should be avoided.
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Affiliation(s)
- Alonso R Riestra
- Hospital Ángeles Lomas and Centro de Neuro-rehabilitación Ángeles, Huixquilucan, Mexico.
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23
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‘Pseudo-neglect’ in CRPS is closer to ‘anti-neglect’ than to classical hemi-neglect? Pain 2012; 153:2157-2158. [DOI: 10.1016/j.pain.2012.07.025] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2012] [Revised: 07/13/2012] [Accepted: 07/20/2012] [Indexed: 11/23/2022]
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Barrett AM, Goedert KM, Basso JC. Prism adaptation for spatial neglect after stroke: translational practice gaps. Nat Rev Neurol 2012; 8:567-77. [PMID: 22926312 DOI: 10.1038/nrneurol.2012.170] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Spatial neglect increases hospital morbidity and costs in around 50% of the 795,000 people per year in the USA who survive stroke, and an urgent need exists to reduce the care burden of this condition. However, effective acute treatment for neglect has been elusive. In this article, we review 48 studies of a treatment of intense neuroscience interest: prism adaptation training. Due to its effects on spatial motor 'aiming', prism adaptation training may act to reduce neglect-related disability. However, research failed, first, to suggest methods to identify the 50-75% of patients who respond to treatment; second, to measure short-term and long-term outcomes in both mechanism-specific and functionally valid ways; third, to confirm treatment utility during the critical first 8 weeks poststroke; and last, to base treatment protocols on systematic dose-response data. Thus, considerable investment in prism adaptation research has not yet touched the fundamentals needed for clinical implementation. We suggest improved standards and better spatial motor models for further research, so as to clarify when, how and for whom prism adaptation should be applied.
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Affiliation(s)
- A M Barrett
- Stroke Rehabilitation Research Laboratory, Kessler Foundation Research Center, 1199 Pleasant Valley Way, West Orange, NJ 07052, USA.
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25
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Heidler-Gary J, Pawlak M, Herskovits EH, Newhart M, Davis C, Trupe LA, Hillis AE. Motor extinction in distinct reference frames: a double dissociation. Behav Neurol 2012; 26:111-9. [PMID: 22713397 PMCID: PMC3459173 DOI: 10.3233/ben-2012-110254] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
OBJECTIVE Test the hypothesis that right hemisphere stroke can cause extinction of left hand movements or movements of either hand held in left space, when both are used simultaneously, possibly depending on lesion site. METHODS 93 non-hemiplegic patients with acute right hemisphere stroke were tested for motor extinction by pressing a counter rapidly for one minute with the right hand, left hand, or both simultaneously with their hands held at their sides, or crossed over midline. RESULTS We identified two distinct types of motor extinction in separate patients; 20 patients extinguished left hand movements held in left or right space (left canonical body extinction); the most significantly associated voxel cluster of ischemic tissue was in the right temporal white matter. Seven patients extinguished either hand held in left space (left space extinction), and the most significantly associated voxel cluster of ischemic tissue was in right parietal white matter. CONCLUSIONS There was a double dissociation between left canonical body extinction and left space motor extinction. Left canonical body extinction seems to be associated with more dorsal (parietal) ischemia, and left canonical body extinction seems to be associated with more ventral (temporal) ischemia.
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Affiliation(s)
- Jennifer Heidler-Gary
- Department of Neurology, Johns Hopkins University, School of Medicine, Baltimore, MD, USA
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26
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Auditory extinction and spatio-temporal order judgment in patients with left- and right-hemisphere lesions. Neuropsychologia 2012; 50:892-903. [DOI: 10.1016/j.neuropsychologia.2012.01.029] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2011] [Revised: 11/28/2011] [Accepted: 01/19/2012] [Indexed: 11/23/2022]
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Jacobs S, Brozzoli C, Farnè A. Neglect: a multisensory deficit? Neuropsychologia 2012; 50:1029-44. [PMID: 22465475 DOI: 10.1016/j.neuropsychologia.2012.03.018] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2011] [Revised: 03/12/2012] [Accepted: 03/16/2012] [Indexed: 11/29/2022]
Abstract
Neglect is a neurological syndrome characterised by a lack of conscious perception of events localised in the contralesional side of space. Here, we consider the possible multisensory nature of this disorder, critically reviewing the literature devoted to multisensory manifestations and processing in neglect. Although its most striking manifestations have been observed in the visual domain, a number of studies demonstrate that neglect can affect virtually any sensory modality, in particular touch and audition. Furthermore, a few recent studies have reported a correlation in severity between visual and non-visual neglect-related deficits evaluated in the same patients, providing some preliminary support for a multisensory conception of neglect. Sensory stimulation and sensorimotor adaptation techniques, aimed at alleviating neglect, have also been shown to affect several sensory modalities, including some that were not directly affected by the intervention. Finally, in some cases neglect can bias multisensory interactions known to occur in healthy individuals, leading to abnormal behaviour or uncovering multisensory compensation mechanisms. This evidence, together with neurophysiological and neuroimaging data revealing the multisensory role played by the areas that are most commonly damaged in neglect patients, seems to speak in favour of neglect as a multisensory disorder. However, since most previous studies were not conducted with the specific purpose of systematically investigating the multisensory nature of neglect, we conclude that more research is needed to appropriately assess this question, and suggest some methodological guidelines that we hope will help clarify this issue. At present, the conception of neglect as a multisensory disorder remains a promising working hypothesis that may help define the pathophysiology of this syndrome.
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Affiliation(s)
- Stéphane Jacobs
- INSERM U1028, CNRS UMR5292, Lyon Neuroscience Research Center, ImpAct Team, Lyon F-69000, France.
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28
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Psychometric evaluation of neglect assessment reveals motor-exploratory predictor of functional disability in acute-stage spatial neglect. Arch Phys Med Rehabil 2012; 93:137-42. [PMID: 22200393 DOI: 10.1016/j.apmr.2011.06.036] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2011] [Revised: 06/14/2011] [Accepted: 06/28/2011] [Indexed: 11/21/2022]
Abstract
OBJECTIVE To determine the psychometric properties of 2 neglect measures, the Behavioral Inattention Test (BIT)-conventional and the Catherine Bergego Scale (CBS), in acute spatial neglect. Spatial neglect is a failure or slowness to respond, orient, or initiate action toward contralesional stimuli, associated with functional disability that impedes stroke recovery. Early identification of specific neglect deficits may identify patients likely to experience chronic disability. However, psychometric evaluation of assessments has focused on subacute/chronic populations. DESIGN Correlational/psychometric study. SETTING Inpatient rehabilitation hospital. PARTICIPANTS Screening identified 51 consecutive patients with a right-hemisphere stroke with left neglect (BIT score <129 or CBS score >11) tested an average of 22.3 days poststroke. INTERVENTIONS Not applicable. MAIN OUTCOME MEASURES We obtained BIT, CBS, and Barthel Index assessments for each participant and clinical and laboratory measures of perceptual-attentional and motor-intentional deficits. RESULTS The BIT showed good reliability and loaded onto a single factor. Consistent with our theoretical prediction, principal components analysis of the CBS identified 2 underlying factors: Where perceptual-attentional items (CBS-PA) and embodied, motor-exploratory items (CBS-ME). The CBS-ME uniquely predicted deficits in activities of daily living (ADLs) assessed by using the Barthel Index, but did not predict clinical and laboratory assessments of motor-intentional bias. More severe neglect on the CBS-PA correlated with greater Where perceptual-attentional bias on clinical and laboratory tests, but did not uniquely predict deficits in ADLs. CONCLUSIONS Our results indicate that assessments of spatial neglect may be used to detect specific motor-exploratory deficits in spatial neglect. Obtaining CBS-ME scores routinely might improve the detection of acute-stage patients with spatial action deficits requiring increased assistance that may persist to the chronic stage.
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Park JW, Kwon YH. Cortical Activation Pattern according to Discrimination of One-Point and Two-Point Tactile Sensory Inputs: an fMRI Study. J Phys Ther Sci 2012. [DOI: 10.1589/jpts.24.101] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Affiliation(s)
- Ji Won Park
- Department of Physical Therapy, College of Medical Science, Catholic University of Daegu
| | - Yong Hyun Kwon
- Department of Physical Therapy, Yeungnam College of Science and Technology
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Mancini F, Bricolo E, Mattioli FC, Vallar G. Visuo-haptic interactions in unilateral spatial neglect: the cross modal judd illusion. Front Psychol 2011; 2:341. [PMID: 22164149 PMCID: PMC3222222 DOI: 10.3389/fpsyg.2011.00341] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2011] [Accepted: 11/01/2011] [Indexed: 11/13/2022] Open
Abstract
Unilateral spatial neglect (USN) has been mainly investigated in the visual modality; only few studies compared spatial neglect across different sensory modalities, and explored their multisensory interactions, with controversial results. We investigated the integration between vision and haptics, through a bisection task of a cross modal illusion, the Judd variant of the Müller-Lyer illusion. We examined right-brain-damaged patients with (n = 7) and without (n = 7) left USN, and neurologically unimpaired participants (n = 14) in the bisection of Judd stimuli under visual, haptic, and visuo-haptic presentation. Neglect patients showed the characteristic rightward bias in the bisection of the baseline stimuli in the visual modality, but not in the haptic and visuo-haptic conditions. The illusory effects were preserved in each group and in each modality, indicating that the processing of the cross modal illusion is independent of the presence of deficits of spatial attention and representation. Spatial neglect can be modality-specific, but visual and tactile sensory inputs are properly integrated.
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Affiliation(s)
- Flavia Mancini
- Department of Psychology, University of Milano-BicoccaMilano, Italy
- Neuropsychological Laboratory, IRCCS Italian Auxological InstituteMilano, Italy
| | - Emanuela Bricolo
- Department of Psychology, University of Milano-BicoccaMilano, Italy
| | | | - Giuseppe Vallar
- Department of Psychology, University of Milano-BicoccaMilano, Italy
- Neuropsychological Laboratory, IRCCS Italian Auxological InstituteMilano, Italy
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Umarova RM, Saur D, Kaller CP, Vry MS, Glauche V, Mader I, Hennig J, Weiller C. Acute visual neglect and extinction: distinct functional state of the visuospatial attention system. Brain 2011; 134:3310-25. [DOI: 10.1093/brain/awr220] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Ting DSJ, Pollock A, Dutton GN, Doubal FN, Ting DSW, Thompson M, Dhillon B. Visual neglect following stroke: current concepts and future focus. Surv Ophthalmol 2011; 56:114-34. [PMID: 21335145 DOI: 10.1016/j.survophthal.2010.08.001] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2010] [Revised: 07/28/2010] [Accepted: 08/03/2010] [Indexed: 11/25/2022]
Abstract
Visual neglect is a common, yet frequently overlooked, neurological disorder following stroke characterized by a deficit in attention and appreciation of stimuli on the contralesional side of the body. It has a profound functional impact on affected individuals. A assessment and management of this condition are hindered, however, by the lack of professional awareness and clinical guidelines. Recent evidence suggests that the underlying deficit in visual attention is due to a disrupted internalized representation of the outer world rather than a disorder of sensory inputs. Dysfunction of the cortical domains and white-matter tracts, as well as inter-hemispheric imbalance, have been implicated in the various manifestations of visual neglect. Optimal diagnosis requires careful history-taking from the patient, family, and friends, in addition to clinical assessment with the line bisection test, the star cancellation test, and the Catherine Bergego Scale. Early recognition and prompt rehabilitation employing a multidisciplinary approach is desirable. Although no treatment has been definitively shown to be of benefit, those with promise include prism adaptation, visual scanning therapy, and virtual reality-based techniques. Further high quality research to seek optimum short- and long-term rehabilitative strategies for visual neglect is required.
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Cuppini C, Magosso E, Ursino M. Organization, maturation, and plasticity of multisensory integration: insights from computational modeling studies. Front Psychol 2011; 2:77. [PMID: 21687448 PMCID: PMC3110383 DOI: 10.3389/fpsyg.2011.00077] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2010] [Accepted: 04/12/2011] [Indexed: 11/15/2022] Open
Abstract
In this paper, we present two neural network models – devoted to two specific and widely investigated aspects of multisensory integration – in order to evidence the potentialities of computational models to gain insight into the neural mechanisms underlying organization, development, and plasticity of multisensory integration in the brain. The first model considers visual–auditory interaction in a midbrain structure named superior colliculus (SC). The model is able to reproduce and explain the main physiological features of multisensory integration in SC neurons and to describe how SC integrative capability – not present at birth – develops gradually during postnatal life depending on sensory experience with cross-modal stimuli. The second model tackles the problem of how tactile stimuli on a body part and visual (or auditory) stimuli close to the same body part are integrated in multimodal parietal neurons to form the perception of peripersonal (i.e., near) space. The model investigates how the extension of peripersonal space – where multimodal integration occurs – may be modified by experience such as use of a tool to interact with the far space. The utility of the modeling approach relies on several aspects: (i) The two models, although devoted to different problems and simulating different brain regions, share some common mechanisms (lateral inhibition and excitation, non-linear neuron characteristics, recurrent connections, competition, Hebbian rules of potentiation and depression) that may govern more generally the fusion of senses in the brain, and the learning and plasticity of multisensory integration. (ii) The models may help interpretation of behavioral and psychophysical responses in terms of neural activity and synaptic connections. (iii) The models can make testable predictions that can help guiding future experiments in order to validate, reject, or modify the main assumptions.
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Affiliation(s)
- Cristiano Cuppini
- Department of Electronics, Computer Science and Systems, University of Bologna Bologna, Italy
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Liu C, Veldhuijzen D, Ohara S, Winberry J, Greenspan J, Lenz F. Spatial attention to thermal pain stimuli in subjects with visual spatial hemi-neglect: extinction, mislocalization and misidentification of stimulus modality. Pain 2011; 152:498-506. [PMID: 21111534 PMCID: PMC3403741 DOI: 10.1016/j.pain.2010.10.017] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2010] [Revised: 09/09/2010] [Accepted: 10/13/2010] [Indexed: 11/27/2022]
Abstract
One approach to the study of disordered spatial attention is to carry out tests of extinction, in which stimuli are detected on the left when they are presented on the left alone, but not when both sides are stimulated simultaneously in a dual simultaneous stimulation (DSS) protocol. Extinction has been documented for multiple sensory modalities, but not for thermal pain stimuli, to our knowledge. We now test the hypothesis that subjects with visual spatial neglect (hemi-neglect) will have alterations in thermal pain sensation which are related to abnormal spatial attention. The results demonstrate that thermal pain extinction of hot and cold pain stimuli occurs in a proportion of subjects with hemi-neglect. In the subjects with visual spatial hemi-neglect but without thermal pain extinction, the sensation of the thermal pain stimulus on the affected (left) side was not extinguished but was often localized to the unaffected (right) side, and the submodality of the stimulus (cold or hot) was often misidentified. Ratios indicating the magnitude of extinction, mislocalization and misidentification were significantly larger on the left side of subjects with visual spatial neglect than in healthy controls or in controls with stroke but without hemineglect. The proportion of subjects with thermal pain extinction, mislocalization, or misidentification was significantly higher in subjects with hemi-neglect than those in either control group. These results demonstrate that disordered attention exerts a powerful effect upon the perception of both the location and the quality of thermal pain stimuli.
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Affiliation(s)
- C.C. Liu
- Neurosurgery Dept., Johns Hopkins Hospital, Baltimore, MD, USA
| | - D.S. Veldhuijzen
- Division of Perioperative Care and Emergency Medicine, Rudolf Magus Institute of Neuroscience, Pain Clinic, University Medical Center Utrecht, Utrecht, The Netherlands
| | - S. Ohara
- Neurosurgery Dept., Johns Hopkins Hospital, Baltimore, MD, USA
| | - J. Winberry
- Neurosurgery Dept., Johns Hopkins Hospital, Baltimore, MD, USA
| | - J.D. Greenspan
- Department of Neural and Pain Sciences, University of Maryland Dental School, Program in Neuroscience, Baltimore, USA
| | - F.A. Lenz
- Neurosurgery Dept., Johns Hopkins Hospital, Baltimore, MD, USA
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Umarova R. [Functional neuroimaging of neglect]. DER NERVENARZT 2010; 81:1438-1443. [PMID: 21076808 DOI: 10.1007/s00115-010-3101-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Though the neglect syndrome is often observed in clinical practice, there are few studies investigating its mechanisms or developing new therapeutic approaches. Most studies on attention were conducted in healthy subjects. In this paper I provide functional neuroimaging data about functional networks for stimuli perception independently from their modality. Additionally, the restoration of stimulus perception and its modulation through emotion are discussed.
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Affiliation(s)
- R Umarova
- Neurologische Universitätsklinik, Breisacher Straße 64, 79106, Freiburg.
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Ticini LF, de Haan B, Klose U, Nägele T, Karnath HO. The Role of Temporo-parietal Cortex in Subcortical Visual Extinction. J Cogn Neurosci 2010; 22:2141-50. [DOI: 10.1162/jocn.2009.21315] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Abstract
Visual extinction is an intriguing defect of awareness in stroke patients, referring to the unsuccessful perception of contralesional events under conditions of competition. Previous studies have investigated the cortical and subcortical brain structures that, when damaged or inactivated, provoke visual extinction. The present experiment asked how lesions of subcortical structures may contribute to the appearance of visual extinction. We investigated whether lesions centering on right basal ganglia may induce dysfunction in distant, structurally intact cortical structures. Normalized perfusion-weighted MRI was used to identify structurally intact but abnormally perfused brain tissue, that is, zones that are receiving enough blood supply to remain structurally intact but not enough to function normally. We compared patients with right basal ganglia lesions showing versus not showing visual extinction. In the extinction patients, the contrast revealed cortical malperfusion that clustered around the right TPJ. It seems as if malfunction of this area is a critical aspect in visual extinction not only after cortical lesion but also in the case of subcortical basal ganglia damage. Our results support the idea that a normally functioning TPJ area plays a decisive role for the attentional network involved in detecting of visual stimuli under conditions of competition.
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Magosso E, Zavaglia M, Serino A, di Pellegrino G, Ursino M. Visuotactile representation of peripersonal space: a neural network study. Neural Comput 2010; 22:190-243. [PMID: 19764874 DOI: 10.1162/neco.2009.01-08-694] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Neurophysiological and behavioral studies suggest that the peripersonal space is represented in a multisensory fashion by integrating stimuli of different modalities. We developed a neural network to simulate the visual-tactile representation of the peripersonal space around the right and left hands. The model is composed of two networks (one per hemisphere), each with three areas of neurons: two are unimodal (visual and tactile) and communicate by synaptic connections with a third downstream multimodal (visual-tactile) area. The hemispheres are interconnected by inhibitory synapses. We applied a combination of analytic and computer simulation techniques. The analytic approach requires some simplifying assumptions and approximations (linearization and a reduced number of neurons) and is used to investigate network stability as a function of parameter values, providing some emergent properties. These are then tested and extended by computer simulations of a more complex nonlinear network that does not rely on the previous simplifications. With basal parameter values, the extended network reproduces several in vivo phenomena: multisensory coding of peripersonal space, reinforcement of unisensory perception by multimodal stimulation, and coexistence of simultaneous right- and left-hand representations in bilateral stimulation. By reducing the strength of the synapses from the right tactile neurons, the network is able to mimic the responses characteristic of right-brain-damaged patients with left tactile extinction: perception of unilateral left tactile stimulation, cross-modal extinction and cross-modal facilitation in bilateral stimulation. Finally, a variety of sensitivity analyses on some key parameters was performed to shed light on the contribution of single-model components in network behaviour. The model may help us understand the neural circuitry underlying peripersonal space representation and identify its alterations explaining neurological deficits. In perspective, it could help in interpreting results of psychophysical and behavioral trials and clarifying the neural correlates of multisensory-based rehabilitation procedures.
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Affiliation(s)
- Elisa Magosso
- Department of Electronics, Computer Science and Systems, University of Bologna, Cesena, Italy.
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Magosso E, Serino A, di Pellegrino G, Ursino M. Crossmodal links between vision and touch in spatial attention: a computational modelling study. COMPUTATIONAL INTELLIGENCE AND NEUROSCIENCE 2010; 2010:304941. [PMID: 19859571 PMCID: PMC2765689 DOI: 10.1155/2010/304941] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/18/2009] [Accepted: 07/28/2009] [Indexed: 11/17/2022]
Abstract
Many studies have revealed that attention operates across different sensory modalities, to facilitate the selection of relevant information in the multimodal situations of every-day life. Cross-modal links have been observed either when attention is directed voluntarily (endogenous) or involuntarily (exogenous). The neural basis of cross-modal attention presents a significant challenge to cognitive neuroscience. Here, we used a neural network model to elucidate the neural correlates of visual-tactile interactions in exogenous and endogenous attention. The model includes two unimodal (visual and tactile) areas connected with a bimodal area in each hemisphere and a competition between the two hemispheres. The model is able to explain cross-modal facilitation both in exogenous and endogenous attention, ascribing it to an advantaged activation of the bimodal area on the attended side (via a top-down or bottom-up biasing), with concomitant inhibition towards the opposite side. The model suggests that a competitive/cooperative interaction with biased competition may mediate both forms of cross-modal attention.
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Affiliation(s)
- Elisa Magosso
- Department of Electronics, Computer Science and Systems, University of Bologna, 40136 Bologna, 47023 Cesena, Italy.
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Shirani P, Thorn J, Davis C, Heidler-Gary J, Newhart M, Gottesman RF, Hillis AE. Severity of hypoperfusion in distinct brain regions predicts severity of hemispatial neglect in different reference frames. Stroke 2009; 40:3563-6. [PMID: 19762699 DOI: 10.1161/strokeaha.109.561969] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND AND PURPOSE Hemispatial neglect is among the most common and disabling consequences of right hemisphere stroke. A variety of variables have been associated with the presence or severity of neglect but have not evaluated the independent effects of location, severity, and volume of ischemia. Few have determined areas involved in different types of neglect. We identified the contributions of these variables to severity of viewer-centered versus stimulus-centered neglect in acute ischemic right hemisphere stroke. METHODS We studied 137 patients within 24 hours of stroke onset with MR diffusion- and perfusion-weighted imaging and a test of hemispatial neglect that distinguishes between viewer-centered and stimulus-centered neglect. Using multivariable linear regression, we identified the independent contributions of severity of ischemia in specific locations, volume of ischemia, and age in accounting for severity of each neglect type. RESULTS Severity of hypoperfusion in angular gyrus was the only variable that significantly and independently contributed to severity of viewer-centered neglect. Volume of dysfunctional tissue and hypoperfusion in posterior frontal cortex also accounted for some variability in severity of viewer-centered neglect. Severity of hypoperfusion of superior temporal cortex was the only variable that independently and significantly contributed to severity of stimulus-centered neglect. CONCLUSIONS Location, severity, and volume of ischemia together determine the type and severity of neglect after right hemisphere stroke. Results also show that perfusion-weighted MRI can be used as a semiquantitative measure of tissue dysfunction in acute stroke and can account for a substantial proportion of the variability in functional deficits in the acute stage.
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Affiliation(s)
- Peyman Shirani
- Department of Medicine, Harbor Hospital, Baylor College of Medicine, Houston, Texas, USA
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Neural codes for somatosensory two-point discrimination in inferior parietal lobule: An fMRI study. Neuroimage 2008; 40:852-858. [DOI: 10.1016/j.neuroimage.2007.12.013] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2007] [Revised: 11/27/2007] [Accepted: 12/05/2007] [Indexed: 11/17/2022] Open
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Carter JC, Lanham DC, Pham D, Bibat G, Naidu S, Kaufmann WE. Selective cerebral volume reduction in Rett syndrome: a multiple-approach MR imaging study. AJNR Am J Neuroradiol 2008; 29:436-41. [PMID: 18065507 DOI: 10.3174/ajnr.a0857] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE Previous studies have examined volumetric abnormalities in Rett syndrome (RTT), using MR imaging and focusing on selective changes. However, these studies preceded the identification of MECP2 as the gene mutated in most RTT cases. We studied regional brain volume changes as noted by MR imaging in girls with RTT who had mutations in the MECP2 gene and more or less severe clinical outcomes to further characterize the neuroanatomy of RTT and its correlations with clinical severity. MATERIALS AND METHODS Complementary semiautomated Talairach- and voxel-based approaches were used to study spoiled gradient-recalled acquisition sequence MR imaging scans from 23 girls with MECP2 mutations/RTT, including a pair of discordant monozygotic twins and 25 age-matched control girls. Both absolute and relative volumetric changes were examined to account for the well-documented global reduction in brain volume seen in RTT. RESULTS Absolute volumetric reductions were observed throughout the brain in RTT. Selective/relative decreases in parietal lobe gray matter, particularly in the dorsal parietal region, and mild, diffuse reductions in cortical white matter were observed in the RTT group compared with control subjects. In girls with RTT and a more severe phenotype, anterior frontal lobe volumes were relatively more reduced. Twin comparisons revealed selective preservation of the occipital cortex. CONCLUSION Selective reductions of dorsal parietal gray matter and preservation of the occipital cortex seem to be basic neuroanatomic features of RTT, whereas preferential reduction of the anterior frontal lobe appears to be a correlate of clinical severity in this disorder. The most affected brain regions include those that may underlie key functional deficits observed in RTT.
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Affiliation(s)
- J C Carter
- Center for Genetic Disorders of Cognition and Behavior, Kennedy Krieger Institute, Baltimore, MD 21211, USA
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Kleinman JT, Sepkuty JP, Hillis AE, Lenz FA, Heidler-Gary J, Gingis L, Crone NE. Spatial neglect during electrocortical stimulation mapping in the right hemisphere. Epilepsia 2007; 48:2365-8. [PMID: 17645542 DOI: 10.1111/j.1528-1167.2007.01196.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Spatial processing was assessed following implantation of subdural electrodes in the nondominant hemisphere with electrocortical stimulation mapping (ESM) in two patients before epilepsy surgery. The first patient had mild hemispatial neglect/extinction during ESM of posterior temporal and inferior parietal areas. These areas were resected, and the patient had postoperative deficits that were similar to those occurring with ESM. The second patient was found to have marked hemispatial neglect during stimulation of parietal areas. These areas were not resected, and the patient had no neglect following surgery. These results suggest that ESM can help predict spatial processing deficits associated with cortical resection, and may help prevent postoperative impairments following resection in right parietal or temporal regions.
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Affiliation(s)
- Jonathan T Kleinman
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21287, USA
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