The Experts below are selected from a list of 246 Experts worldwide ranked by ideXlab platform
Gregory A. Dumanian - One of the best experts on this subject based on the ideXlab platform.
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targeted reinnervation for enhanced prosthetic Arm function in a woman with a proximal Amputation a case study
The Lancet, 2007Co-Authors: Kathy Stubblefield, Paul D. Marasco, Blair A. Lock, Robert D Lipschutz, Laura A. Miller, Todd A Kuiken, Ping Zhou, Gregory A. DumanianAbstract:Summary Background The function of current artificial Arms is limited by inadequate control methods. We developed a technique that used nerve transfers to muscle to develop new electromyogram control signals and nerve transfers to skin, to provide a pathway for cutaneous sensory feedback to the missing hand. Methods We did targeted reinnervation surgery on a woman with a left Arm Amputation at the humeral neck. The ulnar, median, musculocutaneous, and distal radial nerves were transferred to separate segments of her pectoral and serratus muscles. Two sensory nerves were cut and the distal ends were anastomosed to the ulnar and median nerves. After full recovery the patient was fit with a new prosthesis using the additional targeted muscle reinnervation sites. Functional testing was done and sensation in the reinnervated skin was quantified. Findings The patient described the control as intuitive; she thought about using her hand or elbow and the prosthesis responded appropriately. Functional testing showed substantial improvement: mean scores in the blocks and box test increased from 4·0 (SD 1·0) with the conventional prosthesis to 15·6 (1·5) with the new prosthesis. Assessment of Motor and Process Skills test scores increased from 0·30 to 1·98 for motor skills and from 0·90 to 1·98 for process skills. The denervated anterior chest skin was reinnervated by both the ulnar and median nerves; the patient felt that her hand was being touched when this chest skin was touched, with near-normal thresholds in all sensory modalities. Interpretation Targeted reinnervation improved prosthetic function and ease of use in this patient. Targeted sensory reinnervation provides a potential pathway for meaningful sensory feedback.
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Targeted reinnervation for enhanced prosthetic Arm function in a woman with a proximal Amputation: a case study
Lancet, 2007Co-Authors: Todd A Kuiken, Kathy Stubblefield, Paul D. Marasco, Blair A. Lock, Robert D Lipschutz, Laura A. Miller, Ping Zhou, Gregory A. DumanianAbstract:Background: The function of current artificial Arms is limited by inadequate control methods. We developed a technique that used nerve transfers to muscle to develop new electromyogram control signals and nerve transfers to skin, to provide a pathway for cutaneous sensory feedback to the missing hand. Methods: We did targeted reinnervation surgery on a woman with a left Arm Amputation at the humeral neck. The ulnar, median, musculocutaneous, and distal radial nerves were transferred to separate segments of her pectoral and serratus muscles. Two sensory nerves were cut and the distal ends were anastomosed to the ulnar and median nerves. After full recovery the patient was fit with a new prosthesis using the additional targeted muscle reinnervation sites. Functional testing was done and sensation in the reinnervated skin was quantified. Findings: The patient described the control as intuitive; she thought about using her hand or elbow and the prosthesis responded appropriately. Functional testing showed substantial improvement: mean scores in the blocks and box test increased from 4·0 (SD 1·0) with the conventional prosthesis to 15·6 (1·5) with the new prosthesis. Assessment of Motor and Process Skills test scores increased from 0·30 to 1·98 for motor skills and from 0·90 to 1·98 for process skills. The denervated anterior chest skin was reinnervated by both the ulnar and median nerves; the patient felt that her hand was being touched when this chest skin was touched, with near-normal thresholds in all sensory modalities. Interpretation: Targeted reinnervation improved prosthetic function and ease of use in this patient. Targeted sensory reinnervation provides a potential pathway for meaningful sensory feedback. © 2007 Elsevier Ltd. All rights reserved.
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targeted reinnervation for enhanced prosthetic Arm function in a woman with a proximal Amputation a case study commentary
The Lancet, 2007Co-Authors: Leigh R Hochberg, Kathy Stubblefield, Paul D. Marasco, Blair A. Lock, Robert D Lipschutz, Laura A. Miller, Todd A Kuiken, Ping Zhou, Dawn M Taylor, Gregory A. DumanianAbstract:Background The function of current artificial Arms is limited by inadequate control methods. We developed a technique that used nerve transfers to muscle to develop new electromyogram control signals and nerve transfers to skin, to provide a pathway for cutaneous sensory feedback to the missing hand. Methods We did targeted reinnervation surgery on a woman with a left Arm Amputation at the humeral neck. The ulnar, median, musculocutaneous, and distal radial nerves were transferred to separate segments of her pectoral and serratus muscles. Two sensory nerves were cut and the distal ends were anastomosed to the ulnar and median nerves. After full recovery the patient was fit with a new prosthesis using the additional targeted muscle reinnervation sites. Functional testing was done and sensation in the reinnervated skin was quantified. Findings The patient described the control as intuitive; she thought about using her hand or elbow and the prosthesis responded appropriately. Functional testing showed substantial improvement: mean scores in the blocks and box test increased from 4·0 (SD 1·0) with the conventional prosthesis to 15 6 (1·5) with the new prosthesis. Assessment of Motor and Process Skills test scores increased from 0·30 to 1·98 for motor skills and from 0·90 to 1·98 for process skills. The denervated anterior chest skin was reinnervated by both the ulnar and median nerves; the patient felt that her hand was being touched when this chest skin was touched, with near-normal thresholds in all sensory modalities. Interpretation Targeted reinnervation improved prosthetic function and ease of use in this patient. Targeted sensory reinnervation provides a potential pathway for meaningful sensory feedback.
Todd A Kuiken - One of the best experts on this subject based on the ideXlab platform.
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targeted reinnervation for enhanced prosthetic Arm function in a woman with a proximal Amputation a case study
The Lancet, 2007Co-Authors: Kathy Stubblefield, Paul D. Marasco, Blair A. Lock, Robert D Lipschutz, Laura A. Miller, Todd A Kuiken, Ping Zhou, Gregory A. DumanianAbstract:Summary Background The function of current artificial Arms is limited by inadequate control methods. We developed a technique that used nerve transfers to muscle to develop new electromyogram control signals and nerve transfers to skin, to provide a pathway for cutaneous sensory feedback to the missing hand. Methods We did targeted reinnervation surgery on a woman with a left Arm Amputation at the humeral neck. The ulnar, median, musculocutaneous, and distal radial nerves were transferred to separate segments of her pectoral and serratus muscles. Two sensory nerves were cut and the distal ends were anastomosed to the ulnar and median nerves. After full recovery the patient was fit with a new prosthesis using the additional targeted muscle reinnervation sites. Functional testing was done and sensation in the reinnervated skin was quantified. Findings The patient described the control as intuitive; she thought about using her hand or elbow and the prosthesis responded appropriately. Functional testing showed substantial improvement: mean scores in the blocks and box test increased from 4·0 (SD 1·0) with the conventional prosthesis to 15·6 (1·5) with the new prosthesis. Assessment of Motor and Process Skills test scores increased from 0·30 to 1·98 for motor skills and from 0·90 to 1·98 for process skills. The denervated anterior chest skin was reinnervated by both the ulnar and median nerves; the patient felt that her hand was being touched when this chest skin was touched, with near-normal thresholds in all sensory modalities. Interpretation Targeted reinnervation improved prosthetic function and ease of use in this patient. Targeted sensory reinnervation provides a potential pathway for meaningful sensory feedback.
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Targeted reinnervation for enhanced prosthetic Arm function in a woman with a proximal Amputation: a case study
Lancet, 2007Co-Authors: Todd A Kuiken, Kathy Stubblefield, Paul D. Marasco, Blair A. Lock, Robert D Lipschutz, Laura A. Miller, Ping Zhou, Gregory A. DumanianAbstract:Background: The function of current artificial Arms is limited by inadequate control methods. We developed a technique that used nerve transfers to muscle to develop new electromyogram control signals and nerve transfers to skin, to provide a pathway for cutaneous sensory feedback to the missing hand. Methods: We did targeted reinnervation surgery on a woman with a left Arm Amputation at the humeral neck. The ulnar, median, musculocutaneous, and distal radial nerves were transferred to separate segments of her pectoral and serratus muscles. Two sensory nerves were cut and the distal ends were anastomosed to the ulnar and median nerves. After full recovery the patient was fit with a new prosthesis using the additional targeted muscle reinnervation sites. Functional testing was done and sensation in the reinnervated skin was quantified. Findings: The patient described the control as intuitive; she thought about using her hand or elbow and the prosthesis responded appropriately. Functional testing showed substantial improvement: mean scores in the blocks and box test increased from 4·0 (SD 1·0) with the conventional prosthesis to 15·6 (1·5) with the new prosthesis. Assessment of Motor and Process Skills test scores increased from 0·30 to 1·98 for motor skills and from 0·90 to 1·98 for process skills. The denervated anterior chest skin was reinnervated by both the ulnar and median nerves; the patient felt that her hand was being touched when this chest skin was touched, with near-normal thresholds in all sensory modalities. Interpretation: Targeted reinnervation improved prosthetic function and ease of use in this patient. Targeted sensory reinnervation provides a potential pathway for meaningful sensory feedback. © 2007 Elsevier Ltd. All rights reserved.
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targeted reinnervation for enhanced prosthetic Arm function in a woman with a proximal Amputation a case study commentary
The Lancet, 2007Co-Authors: Leigh R Hochberg, Kathy Stubblefield, Paul D. Marasco, Blair A. Lock, Robert D Lipschutz, Laura A. Miller, Todd A Kuiken, Ping Zhou, Dawn M Taylor, Gregory A. DumanianAbstract:Background The function of current artificial Arms is limited by inadequate control methods. We developed a technique that used nerve transfers to muscle to develop new electromyogram control signals and nerve transfers to skin, to provide a pathway for cutaneous sensory feedback to the missing hand. Methods We did targeted reinnervation surgery on a woman with a left Arm Amputation at the humeral neck. The ulnar, median, musculocutaneous, and distal radial nerves were transferred to separate segments of her pectoral and serratus muscles. Two sensory nerves were cut and the distal ends were anastomosed to the ulnar and median nerves. After full recovery the patient was fit with a new prosthesis using the additional targeted muscle reinnervation sites. Functional testing was done and sensation in the reinnervated skin was quantified. Findings The patient described the control as intuitive; she thought about using her hand or elbow and the prosthesis responded appropriately. Functional testing showed substantial improvement: mean scores in the blocks and box test increased from 4·0 (SD 1·0) with the conventional prosthesis to 15 6 (1·5) with the new prosthesis. Assessment of Motor and Process Skills test scores increased from 0·30 to 1·98 for motor skills and from 0·90 to 1·98 for process skills. The denervated anterior chest skin was reinnervated by both the ulnar and median nerves; the patient felt that her hand was being touched when this chest skin was touched, with near-normal thresholds in all sensory modalities. Interpretation Targeted reinnervation improved prosthetic function and ease of use in this patient. Targeted sensory reinnervation provides a potential pathway for meaningful sensory feedback.
Tamar R Makin - One of the best experts on this subject based on the ideXlab platform.
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Brain (re)organisation following Amputation: implications for phantom limb pain.
NeuroImage, 2020Co-Authors: Tamar R Makin, Herta FlorAbstract:Abstract Following Arm Amputation the region that represented the missing hand in primary somatosensory cortex (S1) becomes deprived of its primary input, resulting in changed boundaries of the S1 body map. This remapping process has been termed ‘reorganisation’ and has been attributed to multiple mechanisms, including increased expression of previously masked inputs. In a maladaptive plasticity model, such reorganisation has been associated with phantom limb pain (PLP). Brain activity associated with phantom hand movements is also correlated with PLP, suggesting that preserved limb functional representation may serve as a complementary process. Here we review some of the most recent evidence for the potential drivers and consequences of brain (re)organisation following Amputation, based on human neuroimaging. We emphasise other perceptual and behavioural factors consequential to Arm Amputation, such as non-painful phantom sensations, perceived limb ownership, intact hand compensatory behaviour or prosthesis use, which have also been related to both cortical changes and PLP. We also discuss new findings based on interventions designed to alter the brain representation of the phantom limb, including augmented/virtual reality applications and brain computer interfaces. These studies point to a close interaction of sensory changes and alterations in brain regions involved in body representation, pain processing and motor control. Finally, we review recent evidence based on methodological advances such as high field neuroimaging and multivariate techniques that provide new opportunities to interrogate somatosensory representations in the missing hand cortical territory. Collectively, this research highlights the need to consider potential contributions of additional brain mechanisms, beyond S1 remapping, and the dynamic interplay of contextual factors with brain changes for understanding and alleviating PLP.
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Stability of Sensory Topographies in Adult Cortex
Trends in Cognitive Sciences, 2017Co-Authors: Tamar R Makin, Sliman J. BensmaiaAbstract:Textbooks teach us that the removal of sensory input to sensory cortex, for example, following Arm Amputation, results in massive reorganisation in the adult brain. In this opinion article, we critically examine evidence for functional reorganisation of sensory cortical representations, focusing on the sequelae of Arm Amputation on somatosensory topographies. Based on literature from human and non-human primates, we conclude that the cortical representation of the limb remains remarkably stable despite the loss of its main peripheral input. Furthermore, the purportedly massive reorganisation results primarily from the formation or potentiation of new pathways in subcortical structures and does not produce novel functional sensory representations. We discuss the implications of the stability of sensory representations on the development of upper-limb neuroprostheses.
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Revealing the neural fingerprints of a missing hand
eLife, 2016Co-Authors: Sanne Kikkert, Irene Tracey, Heidi Johansen-berg, James Kolasinski, Saad Jbabdi, Christian F. Beckmann, Tamar R MakinAbstract:The hand area of the primary somatosensory cortex contains detailed finger topography, thought to be shaped and maintained by daily life experience. Here we utilise phantom sensations and ultra high-field neuroimaging to uncover preserved, though latent, representation of amputees’ missing hand. We show that representation of the missing hand’s individual fingers persists in the primary somatosensory cortex even decades after Arm Amputation. By demonstrating stable topography despite Amputation, our finding questions the extent to which continued sensory input is necessary to maintain organisation in sensory cortex, thereby reopening the question what happens to a cortical territory once its main input is lost. The discovery of persistent digit topography of amputees’ missing hand could be exploited for the development of intuitive and fine-grained control of neuroprosthetics, requiring neural signals of individual digits.
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reassessing cortical reorganization in the primary sensorimotor cortex following Arm Amputation
Brain, 2015Co-Authors: Tamar R Makin, Henderson D Slater, Heidi Johansenberg, Jan Scholz, Irene TraceyAbstract:The role of cortical activity in generating and abolishing chronic pain is increasingly emphasized in the clinical community. Perhaps the most striking example of this is the maladaptive plasticity theory, according to which phantom pain arises from remapping of cortically neighbouring representations (lower face) into the territory of the missing hand following Amputation. This theory has been extended to a wide range of chronic pain conditions, such as complex regional pain syndrome. Yet, despite its growing popularity, the evidence to support the maladaptive plasticity theory is largely based on correlations between pain ratings and oftentimes crude measurements of cortical reorganization, with little consideration of potential contributions of other clinical factors, such as adaptive behaviour, in driving the identified brain plasticity. Here, we used a physiologically meaningful measurement of cortical reorganization to reassess its relationship to phantom pain in upper limb amputees. We identified small yet consistent shifts in lip representation contralateral to the missing hand towards, but not invading, the hand area. However, we were unable to identify any statistical relationship between cortical reorganization and phantom sensations or pain either with this measurement or with the traditional Eucledian distance measurement. Instead, we demonstrate that other factors may contribute to the observed remapping. Further research that reassesses more broadly the relationship between cortical reorganization and chronic pain is warranted. * Abbreviations : CoG : centre of gravity SI : primary somatosensory cortex
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network level reorganisation of functional connectivity following Arm Amputation
NeuroImage, 2015Co-Authors: Tamar R Makin, Nicola Filippini, Eugene P Duff, Henderson D Slater, Irene Tracey, Heidi JohansenbergAbstract:One of the most striking demonstrations of plasticity in the adult human brain follows peripheral injury, such as Amputation. In the primary sensorimotor cortex, Arm Amputation results in massive local remapping of the missing hands' cortical territory. However, little is known about the consequences of sensorimotor deprivation on global brain organisation. Here, we used resting-state fMRI to identify large-scale reorganisation beyond the primary sensorimotor cortex in Arm amputees, compared with two-handed controls. Specifically, we characterised changes in functional connectivity between the cortical territory of the missing hand in the primary sensorimotor cortex (‘missing hand cortex’) and two networks of interest: the sensorimotor network, which is typically strongly associated with the hand cortex, and the default mode network (DMN), which is normally dissociated from it. Functional connectivity values between the missing hand cortex and the sensorimotor network were reduced in amputees, and connectivity was weaker in individuals amputated for longer periods. Lower levels of functional coupling between the missing hand cortex and the sensorimotor network were also associated with emerged coupling of this cortex with the DMN. Our results demonstrate that plasticity following Arm Amputation is not restricted to local remapping occurring within the sensorimotor homunculus of the missing hand but rather produces a cascade of cortical reorganisation at a network-level scale. These findings may provide a new framework for understanding how local deprivation following Amputation could elicit complex perceptual experiences of phantom sensations, such as phantom pain.
Laura A. Miller - One of the best experts on this subject based on the ideXlab platform.
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targeted reinnervation for enhanced prosthetic Arm function in a woman with a proximal Amputation a case study
The Lancet, 2007Co-Authors: Kathy Stubblefield, Paul D. Marasco, Blair A. Lock, Robert D Lipschutz, Laura A. Miller, Todd A Kuiken, Ping Zhou, Gregory A. DumanianAbstract:Summary Background The function of current artificial Arms is limited by inadequate control methods. We developed a technique that used nerve transfers to muscle to develop new electromyogram control signals and nerve transfers to skin, to provide a pathway for cutaneous sensory feedback to the missing hand. Methods We did targeted reinnervation surgery on a woman with a left Arm Amputation at the humeral neck. The ulnar, median, musculocutaneous, and distal radial nerves were transferred to separate segments of her pectoral and serratus muscles. Two sensory nerves were cut and the distal ends were anastomosed to the ulnar and median nerves. After full recovery the patient was fit with a new prosthesis using the additional targeted muscle reinnervation sites. Functional testing was done and sensation in the reinnervated skin was quantified. Findings The patient described the control as intuitive; she thought about using her hand or elbow and the prosthesis responded appropriately. Functional testing showed substantial improvement: mean scores in the blocks and box test increased from 4·0 (SD 1·0) with the conventional prosthesis to 15·6 (1·5) with the new prosthesis. Assessment of Motor and Process Skills test scores increased from 0·30 to 1·98 for motor skills and from 0·90 to 1·98 for process skills. The denervated anterior chest skin was reinnervated by both the ulnar and median nerves; the patient felt that her hand was being touched when this chest skin was touched, with near-normal thresholds in all sensory modalities. Interpretation Targeted reinnervation improved prosthetic function and ease of use in this patient. Targeted sensory reinnervation provides a potential pathway for meaningful sensory feedback.
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Targeted reinnervation for enhanced prosthetic Arm function in a woman with a proximal Amputation: a case study
Lancet, 2007Co-Authors: Todd A Kuiken, Kathy Stubblefield, Paul D. Marasco, Blair A. Lock, Robert D Lipschutz, Laura A. Miller, Ping Zhou, Gregory A. DumanianAbstract:Background: The function of current artificial Arms is limited by inadequate control methods. We developed a technique that used nerve transfers to muscle to develop new electromyogram control signals and nerve transfers to skin, to provide a pathway for cutaneous sensory feedback to the missing hand. Methods: We did targeted reinnervation surgery on a woman with a left Arm Amputation at the humeral neck. The ulnar, median, musculocutaneous, and distal radial nerves were transferred to separate segments of her pectoral and serratus muscles. Two sensory nerves were cut and the distal ends were anastomosed to the ulnar and median nerves. After full recovery the patient was fit with a new prosthesis using the additional targeted muscle reinnervation sites. Functional testing was done and sensation in the reinnervated skin was quantified. Findings: The patient described the control as intuitive; she thought about using her hand or elbow and the prosthesis responded appropriately. Functional testing showed substantial improvement: mean scores in the blocks and box test increased from 4·0 (SD 1·0) with the conventional prosthesis to 15·6 (1·5) with the new prosthesis. Assessment of Motor and Process Skills test scores increased from 0·30 to 1·98 for motor skills and from 0·90 to 1·98 for process skills. The denervated anterior chest skin was reinnervated by both the ulnar and median nerves; the patient felt that her hand was being touched when this chest skin was touched, with near-normal thresholds in all sensory modalities. Interpretation: Targeted reinnervation improved prosthetic function and ease of use in this patient. Targeted sensory reinnervation provides a potential pathway for meaningful sensory feedback. © 2007 Elsevier Ltd. All rights reserved.
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targeted reinnervation for enhanced prosthetic Arm function in a woman with a proximal Amputation a case study commentary
The Lancet, 2007Co-Authors: Leigh R Hochberg, Kathy Stubblefield, Paul D. Marasco, Blair A. Lock, Robert D Lipschutz, Laura A. Miller, Todd A Kuiken, Ping Zhou, Dawn M Taylor, Gregory A. DumanianAbstract:Background The function of current artificial Arms is limited by inadequate control methods. We developed a technique that used nerve transfers to muscle to develop new electromyogram control signals and nerve transfers to skin, to provide a pathway for cutaneous sensory feedback to the missing hand. Methods We did targeted reinnervation surgery on a woman with a left Arm Amputation at the humeral neck. The ulnar, median, musculocutaneous, and distal radial nerves were transferred to separate segments of her pectoral and serratus muscles. Two sensory nerves were cut and the distal ends were anastomosed to the ulnar and median nerves. After full recovery the patient was fit with a new prosthesis using the additional targeted muscle reinnervation sites. Functional testing was done and sensation in the reinnervated skin was quantified. Findings The patient described the control as intuitive; she thought about using her hand or elbow and the prosthesis responded appropriately. Functional testing showed substantial improvement: mean scores in the blocks and box test increased from 4·0 (SD 1·0) with the conventional prosthesis to 15 6 (1·5) with the new prosthesis. Assessment of Motor and Process Skills test scores increased from 0·30 to 1·98 for motor skills and from 0·90 to 1·98 for process skills. The denervated anterior chest skin was reinnervated by both the ulnar and median nerves; the patient felt that her hand was being touched when this chest skin was touched, with near-normal thresholds in all sensory modalities. Interpretation Targeted reinnervation improved prosthetic function and ease of use in this patient. Targeted sensory reinnervation provides a potential pathway for meaningful sensory feedback.
Heidi Johansenberg - One of the best experts on this subject based on the ideXlab platform.
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reassessing cortical reorganization in the primary sensorimotor cortex following Arm Amputation
Brain, 2015Co-Authors: Tamar R Makin, Henderson D Slater, Heidi Johansenberg, Jan Scholz, Irene TraceyAbstract:The role of cortical activity in generating and abolishing chronic pain is increasingly emphasized in the clinical community. Perhaps the most striking example of this is the maladaptive plasticity theory, according to which phantom pain arises from remapping of cortically neighbouring representations (lower face) into the territory of the missing hand following Amputation. This theory has been extended to a wide range of chronic pain conditions, such as complex regional pain syndrome. Yet, despite its growing popularity, the evidence to support the maladaptive plasticity theory is largely based on correlations between pain ratings and oftentimes crude measurements of cortical reorganization, with little consideration of potential contributions of other clinical factors, such as adaptive behaviour, in driving the identified brain plasticity. Here, we used a physiologically meaningful measurement of cortical reorganization to reassess its relationship to phantom pain in upper limb amputees. We identified small yet consistent shifts in lip representation contralateral to the missing hand towards, but not invading, the hand area. However, we were unable to identify any statistical relationship between cortical reorganization and phantom sensations or pain either with this measurement or with the traditional Eucledian distance measurement. Instead, we demonstrate that other factors may contribute to the observed remapping. Further research that reassesses more broadly the relationship between cortical reorganization and chronic pain is warranted. * Abbreviations : CoG : centre of gravity SI : primary somatosensory cortex
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network level reorganisation of functional connectivity following Arm Amputation
NeuroImage, 2015Co-Authors: Tamar R Makin, Nicola Filippini, Eugene P Duff, Henderson D Slater, Irene Tracey, Heidi JohansenbergAbstract:One of the most striking demonstrations of plasticity in the adult human brain follows peripheral injury, such as Amputation. In the primary sensorimotor cortex, Arm Amputation results in massive local remapping of the missing hands' cortical territory. However, little is known about the consequences of sensorimotor deprivation on global brain organisation. Here, we used resting-state fMRI to identify large-scale reorganisation beyond the primary sensorimotor cortex in Arm amputees, compared with two-handed controls. Specifically, we characterised changes in functional connectivity between the cortical territory of the missing hand in the primary sensorimotor cortex (‘missing hand cortex’) and two networks of interest: the sensorimotor network, which is typically strongly associated with the hand cortex, and the default mode network (DMN), which is normally dissociated from it. Functional connectivity values between the missing hand cortex and the sensorimotor network were reduced in amputees, and connectivity was weaker in individuals amputated for longer periods. Lower levels of functional coupling between the missing hand cortex and the sensorimotor network were also associated with emerged coupling of this cortex with the DMN. Our results demonstrate that plasticity following Arm Amputation is not restricted to local remapping occurring within the sensorimotor homunculus of the missing hand but rather produces a cascade of cortical reorganisation at a network-level scale. These findings may provide a new framework for understanding how local deprivation following Amputation could elicit complex perceptual experiences of phantom sensations, such as phantom pain.
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non sensory reorganisation following Arm Amputation
Multisensory Research, 2013Co-Authors: Tamar R Makin, Nicola Filippini, Eugene P Duff, Irene Tracey, Jan Scholz, David Henderson Slatere, Heidi JohansenbergAbstract:Arm Amputation has been shown to result in dramatic unisensory reorganisation within the sensorimotor homunculus. However, little is known about the consequences of sensorimotor deprivation on global brain organisation. We studied the interplay between reorganisation within the primary sensorimotor cortex and reorganisation across large-scale brain networks in Arm amputees and controls. Unisensory reorganisation was measured as medial shifts in lip representation in the deprived homunculus using task-based fMRI, reflecting the well-documented invasion of the lip representation into the missing hand area. Network-level reorganisation was assessed as changes in functional connectivity strength between the deprived hand area and fMRI resting-state networks, using independent component analysis. Functional connectivity between the deprived cortex and its network of origin (the sensorimotor network) was reduced in amputees, compared with controls. This was associated with greater coupling of the deprived cortex with the non-sensory default mode network, from which the primary sensorimotor cortex is normally decoupled. The degree of this new (non)sensory coupling was correlated with the degree of unisensory remapping within the sensorimotor homunculus and with decoupling of the deprived hand area from the resting-state sensorimotor network. Our results demonstrate that, following Amputation, plasticity is present in, but not restricted to, the sensorimotor network, highlighting the role of sensory deprivation as a driving force for both sensory and non-sensory plasticity.