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Dempsey-Jones H, Wesselink DB, Friedman J, Makin TR. Organized Toe Maps in Extreme Foot Users. Cell Rep 2020; 28:2748-2756.e4. [PMID: 31509738 PMCID: PMC6899508 DOI: 10.1016/j.celrep.2019.08.027] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2018] [Revised: 03/28/2019] [Accepted: 08/05/2019] [Indexed: 12/11/2022] Open
Abstract
Although the fine-grained features of topographic maps in the somatosensory cortex can be shaped by everyday experience, it is unknown whether behavior can support the expression of somatotopic maps where they do not typically occur. Unlike the fingers, represented in all primates, individuated toe maps have only been found in non-human primates. Using 1-mm resolution fMRI, we identify organized toe maps in two individuals born without either upper limb who use their feet to substitute missing hand function and even support their profession as foot artists. We demonstrate that the ordering and structure of the artists’ toe representation mimics typical hand representation. We further reveal “hand-like” features of activity patterns, not only in the foot area but also similarly in the missing hand area. We suggest humans may have an innate capacity for forming additional topographic maps that can be expressed with appropriate experience. We ask if extreme behavior can cause the (re)emergence of somatotopic maps We investigated two foot artists, born without arms 7T fMRI shows individuated maps of up to 5 toes in the artists but not controls Activity in artists’ foot and hand areas was more “hand-like” than in controls
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Affiliation(s)
| | - Daan B Wesselink
- Institute of Cognitive Neuroscience, University College London, London WC1N 3AZ, UK; Wellcome Centre for Integrative Neuroimaging, University of Oxford, Oxford OX3 9DU, UK.
| | - Jason Friedman
- Physical Therapy Department, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 699 7801, Israel; Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 699 7801, Israel
| | - Tamar R Makin
- Institute of Cognitive Neuroscience, University College London, London WC1N 3AZ, UK
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Wesselink DB, van den Heiligenberg FM, Ejaz N, Dempsey-Jones H, Cardinali L, Tarall-Jozwiak A, Diedrichsen J, Makin TR. Obtaining and maintaining cortical hand representation as evidenced from acquired and congenital handlessness. eLife 2019; 8:37227. [PMID: 30717824 PMCID: PMC6363469 DOI: 10.7554/elife.37227] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Accepted: 01/12/2019] [Indexed: 12/26/2022] Open
Abstract
A key question in neuroscience is how cortical organisation relates to experience. Previously we showed that amputees experiencing highly vivid phantom sensations maintain cortical representation of their missing hand (Kikkert et al., 2016). Here, we examined the role of sensory hand experience on persistent hand representation by studying individuals with acquired and congenital hand loss. We used representational similarity analysis in primary somatosensory and motor cortex during missing and intact hand movements. We found that key aspects of acquired amputees’ missing hand representation persisted, despite varying vividness of phantom sensations. In contrast, missing hand representation of congenital one-handers, who do not experience phantom sensations, was significantly reduced. Across acquired amputees, individuals’ reported motor control over their phantom hand positively correlated with the extent to which their somatosensory hand representation was normally organised. We conclude that once cortical organisation is formed, it is remarkably persistent, despite long-term attenuation of peripheral signals.
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Affiliation(s)
- Daan B Wesselink
- Institute of Cognitive Neuroscience, University College London, London, United Kingdom.,Wellcome Centre for Integrative Neuroimaging, University of Oxford, Oxford, United Kingdom
| | - Fiona Mz van den Heiligenberg
- Institute of Cognitive Neuroscience, University College London, London, United Kingdom.,Wellcome Centre for Integrative Neuroimaging, University of Oxford, Oxford, United Kingdom
| | - Naveed Ejaz
- Brain and Mind Institute, University of Western Ontario, London, Canada.,Department of Computer Science, University of Western Ontario, London, Canada
| | - Harriet Dempsey-Jones
- Institute of Cognitive Neuroscience, University College London, London, United Kingdom.,Wellcome Centre for Integrative Neuroimaging, University of Oxford, Oxford, United Kingdom
| | - Lucilla Cardinali
- Brain and Mind Institute, University of Western Ontario, London, Canada.,Unit for Visually Impaired People, Istituto Italiano di Tecnologia, Genoa, Italy
| | | | - Jörn Diedrichsen
- Brain and Mind Institute, University of Western Ontario, London, Canada.,Department of Computer Science, University of Western Ontario, London, Canada
| | - Tamar R Makin
- Institute of Cognitive Neuroscience, University College London, London, United Kingdom.,Wellcome Centre for Integrative Neuroimaging, University of Oxford, Oxford, United Kingdom.,Wellcome Centre for Human Neuroimaging, University College London, London, United Kingdom
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