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Lamorie-Foote K, Kramer DR, Sundaram S, Cavaleri J, Gilbert ZD, Tang AM, Bashford L, Liu CY, Kellis S, Lee B. Primary somatosensory cortex organization for engineering artificial somatosensation. Neurosci Res 2024:S0168-0102(24)00009-9. [PMID: 38278220 DOI: 10.1016/j.neures.2024.01.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Revised: 01/12/2024] [Accepted: 01/17/2024] [Indexed: 01/28/2024]
Abstract
Somatosensory deficits from stroke, spinal cord injury, or other neurologic damage can lead to a significant degree of functional impairment. The primary (SI) and secondary (SII) somatosensory cortices encode information in a medial to lateral organization. SI is generally organized topographically, with more discrete cortical representations of specific body regions. SII regions corresponding to anatomical areas are less discrete and may represent a more functional rather than topographic organization. Human somatosensory research continues to map cortical areas of sensory processing with efforts primarily focused on hand and upper extremity information in SI. However, research into SII and other body regions is lacking. In this review, we synthesize the current state of knowledge regarding the cortical organization of human somatosensation and discuss potential applications for brain computer interface. In addition to accurate individualized mapping of cortical somatosensation, further research is required to uncover the neurophysiological mechanisms of how somatosensory information is encoded in the cortex.
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Affiliation(s)
- Krista Lamorie-Foote
- Department of Neurological Surgery, Keck School of Medicine of USC, University of Southern California, Los Angeles, CA, United States
| | - Daniel R Kramer
- Department of Neurological Surgery, Keck School of Medicine of USC, University of Southern California, Los Angeles, CA, United States; Department of Neurological Surgery, University of Colorado School of Medicine, Denver, CO, United States
| | - Shivani Sundaram
- Department of Neurological Surgery, Keck School of Medicine of USC, University of Southern California, Los Angeles, CA, United States.
| | - Jonathon Cavaleri
- Department of Neurological Surgery, Keck School of Medicine of USC, University of Southern California, Los Angeles, CA, United States
| | - Zachary D Gilbert
- Department of Neurological Surgery, Keck School of Medicine of USC, University of Southern California, Los Angeles, CA, United States
| | - Austin M Tang
- Department of Neurological Surgery, Keck School of Medicine of USC, University of Southern California, Los Angeles, CA, United States; Department of Neurological Surgery, University of Texas at Houston, Houston, TX, United States
| | - Luke Bashford
- Department of Biology and Biological Engineering, T&C Chen Institute for Neuroscience, California Institute of Technology, Pasadena, CA, United States; Department of Neuroscience, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Charles Y Liu
- Department of Neurological Surgery, Keck School of Medicine of USC, University of Southern California, Los Angeles, CA, United States; USC Neurorestoration Center, Keck School of Medicine of USC, Los Angeles, CA, United States
| | - Spencer Kellis
- Department of Neurological Surgery, Keck School of Medicine of USC, University of Southern California, Los Angeles, CA, United States; USC Neurorestoration Center, Keck School of Medicine of USC, Los Angeles, CA, United States
| | - Brian Lee
- Department of Neurological Surgery, Keck School of Medicine of USC, University of Southern California, Los Angeles, CA, United States; USC Neurorestoration Center, Keck School of Medicine of USC, Los Angeles, CA, United States
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2
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Schone HR, Maimon Mor RO, Kollamkulam M, Gerrand C, Woollard A, Kang NV, Baker CI, Makin TR. Stable Cortical Body Maps Before and After Arm Amputation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.13.571314. [PMID: 38168448 PMCID: PMC10760201 DOI: 10.1101/2023.12.13.571314] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2024]
Abstract
Neuroscientists have long debated the adult brain's capacity to reorganize itself in response to injury. A driving model for studying plasticity has been limb amputation. For decades, it was believed that amputation triggers large-scale reorganization of cortical body resources. However, these studies have relied on cross-sectional observations post-amputation, without directly tracking neural changes. Here, we longitudinally followed adult patients with planned arm amputations and measured hand and face representations, before and after amputation. By interrogating the representational structure elicited from movements of the hand (pre-amputation) and phantom hand (post-amputation), we demonstrate that hand representation is unaltered. Further, we observed no evidence for lower face (lip) reorganization into the deprived hand region. Collectively, our findings provide direct and decisive evidence that amputation does not trigger large-scale cortical reorganization.
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Affiliation(s)
- Hunter R. Schone
- Institute of Cognitive Neuroscience, University College London, London, UK
- Laboratory of Brain & Cognition, National Institutes of Mental Health, National Institutes of Health, Bethesda, Maryland, USA
- Rehab Neural Engineering Labs, University of Pittsburgh, Pittsburgh, PA, USA
- Department of Physical Medicine and Rehabilitation, University of Pittsburgh, Pittsburgh, PA, USA
| | - Roni O. Maimon Mor
- Institute of Cognitive Neuroscience, University College London, London, UK
- Department of Experimental Psychology, University College London, London, UK
- UCL Institute of Ophthalmology, University College London, London, UK
| | - Mathew Kollamkulam
- Institute of Cognitive Neuroscience, University College London, London, UK
- Department of Experimental Psychology, University of Oxford, Oxford, UK
| | - Craig Gerrand
- Department of Orthopaedic Oncology, Royal National Orthopaedic Hospital NHS Trust, Stanmore, Middlesex, UK
| | | | - Norbert V. Kang
- Plastic Surgery Department, Royal Free Hospital NHS Trust, London, UK
| | - Chris I. Baker
- Laboratory of Brain & Cognition, National Institutes of Mental Health, National Institutes of Health, Bethesda, Maryland, USA
| | - Tamar R. Makin
- Institute of Cognitive Neuroscience, University College London, London, UK
- Wellcome Centre for Human Neuroimaging, UCL Institute of Neurology, London, UK
- MRC Cognition and Brain Sciences Unit, University of Cambridge, Cambridge, UK
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3
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Abstract
Neurological insults, such as congenital blindness, deafness, amputation, and stroke, often result in surprising and impressive behavioural changes. Cortical reorganisation, which refers to preserved brain tissue taking on a new functional role, is often invoked to account for these behavioural changes. Here, we revisit many of the classical animal and patient cortical remapping studies that spawned this notion of reorganisation. We highlight empirical, methodological, and conceptual problems that call this notion into doubt. We argue that appeal to the idea of reorganisation is attributable in part to the way that cortical maps are empirically derived. Specifically, cortical maps are often defined based on oversimplified assumptions of 'winner-takes-all', which in turn leads to an erroneous interpretation of what it means when these maps appear to change. Conceptually, remapping is interpreted as a circuit receiving novel input and processing it in a way unrelated to its original function. This implies that neurons are either pluripotent enough to change what they are tuned to or that a circuit can change what it computes. Instead of reorganisation, we argue that remapping is more likely to occur due to potentiation of pre-existing architecture that already has the requisite representational and computational capacity pre-injury. This architecture can be facilitated via Hebbian and homeostatic plasticity mechanisms. Crucially, our revised framework proposes that opportunities for functional change are constrained throughout the lifespan by the underlying structural 'blueprint'. At no period, including early in development, does the cortex offer structural opportunities for functional pluripotency. We conclude that reorganisation as a distinct form of cortical plasticity, ubiquitously evoked with words such as 'take-over'' and 'rewiring', does not exist.
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Affiliation(s)
- Tamar R Makin
- MRC Cognition and Brain Sciences Unit, University of CambridgeCambridgeUnited Kingdom
| | - John W Krakauer
- Department of Neuroscience, Johns Hopkins University School of MedicineBaltimoreUnited States
- Department of Neurology, Johns Hopkins University School of MedicineBaltimoreUnited States
- The Santa Fe InstituteSanta FeUnited States
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4
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Amoruso E, Terhune DB, Kromm M, Kirker S, Muret D, Makin TR. Reassessing referral of touch following peripheral deafferentation: The role of contextual bias. Cortex 2023; 167:167-177. [PMID: 37567052 PMCID: PMC11139647 DOI: 10.1016/j.cortex.2023.04.019] [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: 06/20/2022] [Revised: 01/28/2023] [Accepted: 04/21/2023] [Indexed: 08/13/2023]
Abstract
Some amputees have been famously reported to perceive facial touch as arising from their phantom hand. These referred sensations have since been replicated across multiple neurological disorders and were classically interpreted as a perceptual correlate of cortical plasticity. Common to all these and related studies is that participants might have been influenced in their self-reports by the experimental design or related contextual biases. Here, we investigated whether referred sensations reports might be confounded by demand characteristics (e.g., compliance, expectation, suggestion). Unilateral upper-limb amputees (N = 18), congenital one-handers (N = 19), and two-handers (N = 22) were repeatedly stimulated with computer-controlled vibrations on 10 body-parts and asked to report the occurrence of any concurrent sensations on their hand(s). To further manipulate expectations, we gave participants the suggestion that some of these vibrations had a higher probability to evoke referred sensations. We also assessed similarity between (phantom) hand and face representation in primary somatosensory cortex (S1), using functional Magnetic Resonance Imaging (fMRI) multivariate representational similarity analysis. We replicated robust reports of referred sensations in amputees towards their phantom hand; however, the frequency and distribution of reported referred sensations were similar across groups. Moreover, referred sensations were evoked by stimulation of multiple body-parts and similarly reported on both the intact and phantom hand in amputees. Face-to-phantom-hand representational similarity was not different in amputees' missing hand region, compared with controls. These findings weaken the interpretation of referred sensations as a perceptual correlate of S1 plasticity and reveal the need to account for contextual biases when evaluating anomalous perceptual phenomena.
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Affiliation(s)
- Elena Amoruso
- Institute of Cognitive Neuroscience, University College London, London WC1N 3AZ, UK
| | - Devin B Terhune
- Department of Psychology, Goldsmiths, University of London, London SE14 6NW, UK
| | - Maria Kromm
- Institute of Cognitive Neuroscience, University College London, London WC1N 3AZ, UK
| | - Stephen Kirker
- Cambridge University Hospitals NHS Foundation Trust, Cambridge CB2 0QQ, UK
| | - Dollyane Muret
- Institute of Cognitive Neuroscience, University College London, London WC1N 3AZ, UK.
| | - Tamar R Makin
- Institute of Cognitive Neuroscience, University College London, London WC1N 3AZ, UK; Wellcome Trust Centre for Neuroimaging, University College London, London WC1N 3AR, UK
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5
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Marneweck M, Gardner C, Dundon NM, Smith J, Frey SH. Reorganization of sensorimotor representations of the intact limb after upper but not lower limb traumatic amputation. Neuroimage Clin 2023; 39:103499. [PMID: 37634375 PMCID: PMC10470418 DOI: 10.1016/j.nicl.2023.103499] [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] [Accepted: 08/16/2023] [Indexed: 08/29/2023]
Abstract
It is becoming increasingly clear that limb loss induces wider spread reorganization of representations of the body that are nonadjacent to the affected cortical territory. Data from upper extremity amputees reveal intrusion of the representation of the ipsilateral intact limb into the former hand territory. Here we test for the first time whether this reorganization of the intact limb into the deprived cortex is specific to the neurological organization of the upper limbs or reflects large scale adaptation that is triggered by any unilateral amputation. BOLD activity was measured as human subjects with upper limb and lower limb traumatic amputation and their controls moved the toes on each foot, open and closed each hand and pursed their lips. Subjects with amputation were asked to imagine moving the missing limb while remaining still. Bayesian pattern component modeling of fMRI data showed that intact ipsilateral movements and contralateral movements of the hand and foot were distinctly represented in the deprived sensorimotor cortex years after upper limb amputation. In contrast, there was evidence reminiscent of contralateral specificity for hand and foot movements following lower limb amputation, like that seen in controls. We propose the cortical reorganization of the intact limb to be a function of use-dependent plasticity that is more specific to the consequence of upper limb loss of forcing an asymmetric reliance on the intact hand and arm. The contribution of this reorganization to phantom pain or a heightened risk of overuse and resultant maladaptive plasticity needs investigating before targeting such reorganization in intervention.
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Affiliation(s)
| | - Cooper Gardner
- Department of Human Physiology, University of Oregon, Eugene, OR, USA
| | - Neil M Dundon
- Department of Brain and Psychological Sciences, University of California Santa Barbara, Santa Barbara, CA, USA; Department of Child and Adolescent Psychiatry, Psychotherapy and Psychosomatics, University of Freiburg, 79104 Freiburg, Germany
| | - Jolinda Smith
- Department of Human Physiology, University of Oregon, Eugene, OR, USA
| | - Scott H Frey
- Department of Psychological Sciences, University of Missouri, Columbia, MO, USA
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6
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Sanders Z, Dempsey‐Jones H, Wesselink DB, Edmondson LR, Puckett AM, Saal HP, Makin TR. Similar somatotopy for active and passive digit representation in primary somatosensory cortex. Hum Brain Mapp 2023; 44:3568-3585. [PMID: 37145934 PMCID: PMC10203813 DOI: 10.1002/hbm.26298] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2022] [Revised: 12/11/2022] [Accepted: 03/13/2023] [Indexed: 05/07/2023] Open
Abstract
Scientists traditionally use passive stimulation to examine the organisation of primary somatosensory cortex (SI). However, given the close, bidirectional relationship between the somatosensory and motor systems, active paradigms involving free movement may uncover alternative SI representational motifs. Here, we used 7 Tesla functional magnetic resonance imaging to compare hallmark features of SI digit representation between active and passive tasks which were unmatched on task or stimulus properties. The spatial location of digit maps, somatotopic organisation, and inter-digit representational structure were largely consistent between tasks, indicating representational consistency. We also observed some task differences. The active task produced higher univariate activity and multivariate representational information content (inter-digit distances). The passive task showed a trend towards greater selectivity for digits versus their neighbours. Our findings highlight that, while the gross features of SI functional organisation are task invariant, it is important to also consider motor contributions to digit representation.
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Affiliation(s)
- Zeena‐Britt Sanders
- Wellcome Centre of Integrative NeuroimagingFMRIB, John Radcliffe HospitalOxfordUK
| | - Harriet Dempsey‐Jones
- Institute of Cognitive NeuroscienceUniversity College LondonLondonUK
- School of PsychologyThe University of QueenslandBrisbaneAustralia
| | - Daan B. Wesselink
- Wellcome Centre of Integrative NeuroimagingFMRIB, John Radcliffe HospitalOxfordUK
- Institute of Cognitive NeuroscienceUniversity College LondonLondonUK
| | | | - Alexander M. Puckett
- School of PsychologyThe University of QueenslandBrisbaneAustralia
- Queensland Brain InstituteThe University of QueenslandBrisbaneAustralia
| | - Hannes P. Saal
- Queensland Brain InstituteThe University of QueenslandBrisbaneAustralia
| | - Tamar R. Makin
- Wellcome Centre of Integrative NeuroimagingFMRIB, John Radcliffe HospitalOxfordUK
- Institute of Cognitive NeuroscienceUniversity College LondonLondonUK
- MRC Cognition and Brain Sciences UnitUniversity of CambridgeCambridgeUK
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7
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Doehler J, Northall A, Liu P, Fracasso A, Chrysidou A, Speck O, Lohmann G, Wolbers T, Kuehn E. The 3D Structural Architecture of the Human Hand Area Is Nontopographic. J Neurosci 2023; 43:3456-3476. [PMID: 37001994 PMCID: PMC10184749 DOI: 10.1523/jneurosci.1692-22.2023] [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: 09/04/2022] [Revised: 02/15/2023] [Accepted: 03/15/2023] [Indexed: 04/03/2023] Open
Abstract
The functional topography of the human primary somatosensory cortex hand area is a widely studied model system to understand sensory organization and plasticity. It is so far unclear whether the underlying 3D structural architecture also shows a topographic organization. We used 7 Tesla (7T) magnetic resonance imaging (MRI) data to quantify layer-specific myelin, iron, and mineralization in relation to population receptive field maps of individual finger representations in Brodman area 3b (BA 3b) of human S1 in female and male younger adults. This 3D description allowed us to identify a characteristic profile of layer-specific myelin and iron deposition in the BA 3b hand area, but revealed an absence of structural differences, an absence of low-myelin borders, and high similarity of 3D microstructure profiles between individual fingers. However, structural differences and borders were detected between the hand and face areas. We conclude that the 3D structural architecture of the human hand area is nontopographic, unlike in some monkey species, which suggests a high degree of flexibility for functional finger organization and a new perspective on human topographic plasticity.SIGNIFICANCE STATEMENT Using ultra-high-field MRI, we provide the first comprehensive in vivo description of the 3D structural architecture of the human BA 3b hand area in relation to functional population receptive field maps. High similarity of precise finger-specific 3D profiles, together with an absence of structural differences and an absence of low-myelin borders between individual fingers, reveals the 3D structural architecture of the human hand area to be nontopographic. This suggests reduced structural limitations to cortical plasticity and reorganization and allows for shared representational features across fingers.
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Affiliation(s)
- Juliane Doehler
- Institute for Cognitive Neurology and Dementia Research, Medical Faculty, Otto-von-Guericke University Magdeburg, 39120 Magdeburg, Germany
- German Center for Neurodegenerative Diseases, 39120 Magdeburg, Germany
| | - Alicia Northall
- Institute for Cognitive Neurology and Dementia Research, Medical Faculty, Otto-von-Guericke University Magdeburg, 39120 Magdeburg, Germany
- German Center for Neurodegenerative Diseases, 39120 Magdeburg, Germany
| | - Peng Liu
- Institute for Cognitive Neurology and Dementia Research, Medical Faculty, Otto-von-Guericke University Magdeburg, 39120 Magdeburg, Germany
- German Center for Neurodegenerative Diseases, 39120 Magdeburg, Germany
| | - Alessio Fracasso
- Institute of Neuroscience and Psychology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - Anastasia Chrysidou
- Institute for Cognitive Neurology and Dementia Research, Medical Faculty, Otto-von-Guericke University Magdeburg, 39120 Magdeburg, Germany
- German Center for Neurodegenerative Diseases, 39120 Magdeburg, Germany
| | - Oliver Speck
- German Center for Neurodegenerative Diseases, 39120 Magdeburg, Germany
- Department of Biomedical Magnetic Resonance, Otto-von-Guericke-University Magdeburg, 39120 Magdeburg, Germany
- Center for Behavioral Brain Sciences, 39120 Magdeburg, Germany
- Leibniz Institute for Neurobiology, 39120 Magdeburg, Germany
| | - Gabriele Lohmann
- Max Planck Institute for Biological Cybernetics, 72076 Tübingen, Germany
| | - Thomas Wolbers
- German Center for Neurodegenerative Diseases, 39120 Magdeburg, Germany
- Center for Behavioral Brain Sciences, 39120 Magdeburg, Germany
| | - Esther Kuehn
- Hertie Institute for Clinical Brain Research, 72076 Tübingen, Germany
- Institute for Cognitive Neurology and Dementia Research, Medical Faculty, Otto-von-Guericke University Magdeburg, 39120 Magdeburg, Germany
- German Center for Neurodegenerative Diseases, 39120 Magdeburg, Germany
- Center for Behavioral Brain Sciences, 39120 Magdeburg, Germany
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8
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Rosenthal IA, Bashford L, Kellis S, Pejsa K, Lee B, Liu C, Andersen RA. S1 represents multisensory contexts and somatotopic locations within and outside the bounds of the cortical homunculus. Cell Rep 2023; 42:112312. [PMID: 37002922 PMCID: PMC10544688 DOI: 10.1016/j.celrep.2023.112312] [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: 09/15/2022] [Revised: 02/06/2023] [Accepted: 03/13/2023] [Indexed: 04/03/2023] Open
Abstract
Recent literature suggests that tactile events are represented in the primary somatosensory cortex (S1) beyond its long-established topography; in addition, the extent to which S1 is modulated by vision remains unclear. To better characterize S1, human electrophysiological data were recorded during touches to the forearm or finger. Conditions included visually observed physical touches, physical touches without vision, and visual touches without physical contact. Two major findings emerge from this dataset. First, vision strongly modulates S1 area 1, but only if there is a physical element to the touch, suggesting that passive touch observation is insufficient to elicit neural responses. Second, despite recording in a putative arm area of S1, neural activity represents both arm and finger stimuli during physical touches. Arm touches are encoded more strongly and specifically, supporting the idea that S1 encodes tactile events primarily through its topographic organization but also more generally, encompassing other areas of the body.
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Affiliation(s)
- Isabelle A Rosenthal
- Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA; T&C Chen Brain-machine Interface Center, California Institute of Technology, Pasadena, CA 91125, USA.
| | - Luke Bashford
- Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA; T&C Chen Brain-machine Interface Center, California Institute of Technology, Pasadena, CA 91125, USA
| | - Spencer Kellis
- Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA; T&C Chen Brain-machine Interface Center, California Institute of Technology, Pasadena, CA 91125, USA; Department of Neurological Surgery, Keck School of Medicine of USC, Los Angeles, CA 90033, USA; USC Neurorestoration Center, Keck School of Medicine of USC, Los Angeles, CA 90033, USA
| | - Kelsie Pejsa
- Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA; T&C Chen Brain-machine Interface Center, California Institute of Technology, Pasadena, CA 91125, USA
| | - Brian Lee
- Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA; Department of Neurological Surgery, Keck School of Medicine of USC, Los Angeles, CA 90033, USA; USC Neurorestoration Center, Keck School of Medicine of USC, Los Angeles, CA 90033, USA
| | - Charles Liu
- Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA; Department of Neurological Surgery, Keck School of Medicine of USC, Los Angeles, CA 90033, USA; USC Neurorestoration Center, Keck School of Medicine of USC, Los Angeles, CA 90033, USA; Rancho Los Amigos National Rehabilitation Center, Downey, CA 90242, USA
| | - Richard A Andersen
- Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA; T&C Chen Brain-machine Interface Center, California Institute of Technology, Pasadena, CA 91125, USA
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9
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Chauhan ISJ, Cole JD, Berthoz A, Sarlegna FR. Dissociation between dreams and wakefulness: Insights from body and action representations of rare individuals with massive somatosensory deafferentation. Conscious Cogn 2022; 106:103415. [PMID: 36252519 DOI: 10.1016/j.concog.2022.103415] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Revised: 06/27/2022] [Accepted: 09/17/2022] [Indexed: 01/27/2023]
Abstract
The realism of body and actions in dreams is thought to be induced by simulations based on internal representations used during wakefulness. As somatosensory signals contribute to the updating of body and action representations, these are impaired when somatosensory signals are lacking. Here, we tested the hypothesis that individuals with somatosensory deafferentation have impaired body and actions in their dreams, as in wakefulness. We questioned three individuals with a severe, acquired sensory neuropathy on their dreams. While deafferented participants were impaired in daily life, they could dream of themselves as able-bodied, with some sensations (touch, proprioception) and actions (such as running or jumping) which had not been experienced in physical life since deafferentation. We speculate that simulation in dreams could be based on former, "healthy" body and action representations. Our findings are consistent with the idea that distinct body and action representations may be used during dreams and wakefulness.
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Affiliation(s)
- Ishan-Singh J Chauhan
- Aix Marseille Univ, CNRS, ISM, Marseille, France; Université Paris Nanterre, Nanterre, France.
| | - Jonathan D Cole
- Centre of Postgraduate Research and Education, Bournemouth University, Bournemouth, UK
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10
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Philip BA, Valyear KF, Cirstea CM, Baune NA, Kaufman C, Frey SH. Changes in Primary Somatosensory Cortex Following Allogeneic Hand Transplantation or Autogenic Hand Replantation. FRONTIERS IN NEUROIMAGING 2022; 1:919694. [PMID: 36590253 PMCID: PMC9802660 DOI: 10.3389/fnimg.2022.919694] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Accepted: 09/09/2022] [Indexed: 01/03/2023]
Abstract
Former amputees who undergo allogeneic hand transplantation or autogenic hand replantation (jointly, "hand restoration") present a unique opportunity to measure the range of post-deafferentation plastic changes in the nervous system, especially primary somatosensory cortex (S1). However, few such patients exist, and previous studies compared single cases to small groups of typical adults. Here, we studied 5 individuals (n = 8 sessions: a transplant with 2 sessions, a transplant with 3 sessions, and three replants with 1 session each). We used functional magnetic resonance imaging (fMRI) to measure S1 responsiveness to controlled pneumatic tactile stimulation delivered to each patient's left and right fingertips and lower face. These data were compared with responses acquired from typical adults (n = 29) and current unilateral amputees (n = 19). During stimulation of the affected hand, patients' affected S1 (contralateral to affected hand) responded to stimulation in a manner similar both to amputees and to typical adults. The presence of contralateral responses indicated grossly typical S1 function, but responses were universally at the low end of the range of typical variability. Patients' affected S1 showed substantial individual variability in responses to stimulation of the intact hand: while all patients fell within the range of typical adults, some patient sessions (4/8) had substantial ipsilateral responses similar to those exhibited by current amputees. Unlike hand restoration patients, current amputees exhibited substantial S1 reorganization compared to typical adults, including bilateral S1 responses to stimulation of the intact hand. In all three participant groups, we assessed tactile localization by measuring individuals' ability to identify the location of touch on the palm and fingers. Curiously, while transplant patients improved their tactile sensory localization over time, this was uncorrelated with changes in S1 responses to tactile stimuli. Overall, our results provide the first description of cortical responses to well-controlled tactile stimulation after hand restoration. Our case studies indicate that hand restoration patients show S1 function within the range of both typical adults and amputees, but with low-amplitude and individual-specific responses that indicate a wide range of potential cortical neurological changes following de-afferentation and re-afferentation.
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Affiliation(s)
- Benjamin A. Philip
- Department of Psychological Sciences, University of Missouri, Columbia, MO, United States
- Program in Occupational Therapy, Washington University School of Medicine, St. Louis, MO, United States
| | - Kenneth F. Valyear
- Department of Psychological Sciences, University of Missouri, Columbia, MO, United States
- School of Human and Behavioural Sciences, Bangor University, Bangor, United Kingdom
| | - Carmen M. Cirstea
- Department of Physical Medicine and Rehabilitation, University of Missouri, Columbia, MO, United States
| | - Nathan A. Baune
- Department of Psychological Sciences, University of Missouri, Columbia, MO, United States
- Program in Occupational Therapy, Washington University School of Medicine, St. Louis, MO, United States
| | - Christina Kaufman
- Department of Cardiovascular and Thoracic Surgery, University of Louisville School of Medicine, Louisville, KY, United States
| | - Scott H. Frey
- Department of Psychological Sciences, University of Missouri, Columbia, MO, United States
- Department of Physical Medicine and Rehabilitation, University of Missouri, Columbia, MO, United States
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11
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Hakonen M, Nurmi T, Vallinoja J, Jaatela J, Piitulainen H. More comprehensive proprioceptive stimulation of the hand amplifies its cortical processing. J Neurophysiol 2022; 128:568-581. [PMID: 35858122 PMCID: PMC9423773 DOI: 10.1152/jn.00485.2021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
Corticokinematic coherence (CKC) quantifies the phase coupling between limb kinematics and cortical neurophysiological signals reflecting proprioceptive feedback to the primary sensorimotor (SM1) cortex. We studied whether the CKC strength or cortical source location differs between proprioceptive stimulation (i.e., actuator-evoked movements) of right-hand digits (index, middle, ring, and little). Twenty-one volunteers participated in magnetoencephalography measurements during which three conditions were tested: 1) simultaneous stimulation of all four fingers at the same frequency, 2) stimulation of each finger separately at the same frequency, and 3) simultaneous stimulation of the fingers at finger-specific frequencies. CKC was computed between MEG responses and accelerations of the fingers recorded with three-axis accelerometers. CKC was stronger (P < 0.003) for the simultaneous (0.52 ± 0.02) than separate (0.45 ± 0.02) stimulation at the same frequency. Furthermore, CKC was weaker (P < 0.03) for the simultaneous stimulation at the finger-specific frequencies (0.38 ± 0.02) than for the separate stimulation. CKC source locations of the fingers were concentrated in the hand region of the SM1 cortex and did not follow consistent finger-specific somatotopic order. Our results indicate that proprioceptive afference from the fingers is processed in partly overlapping cortical neuronal circuits, which was demonstrated by the modulation of the finger-specific CKC strengths due to proprioceptive afference arising from simultaneous stimulation of the other fingers of the same hand as well as overlapping cortical source locations. Finally, comprehensive simultaneous proprioceptive stimulation of the hand would optimize functional cortical mapping to pinpoint the hand region, e.g., prior brain surgery. NEW & NOTEWORTHY Corticokinematic coherence (CKC) can be used to study cortical proprioceptive processing and localize proprioceptive hand representation. Our results indicate that proprioceptive stimulation delivered simultaneously at the same frequency to fingers (D2–D4) maximizes CKC strength allowing robust and fast localization of the human hand region in the sensorimotor cortex using MEG.
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Affiliation(s)
- Maria Hakonen
- Faculty of Sport and Health Sciences, University of Jyväskylä, Jyväskylä, Finland.,Department of Neuroscience and Biomedical Engineering, Aalto University School of Science, Espoo, Finland.,Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, United States
| | - Timo Nurmi
- Faculty of Sport and Health Sciences, University of Jyväskylä, Jyväskylä, Finland.,Department of Neuroscience and Biomedical Engineering, Aalto University School of Science, Espoo, Finland
| | - Jaakko Vallinoja
- Department of Neuroscience and Biomedical Engineering, Aalto University School of Science, Espoo, Finland
| | - Julia Jaatela
- Department of Neuroscience and Biomedical Engineering, Aalto University School of Science, Espoo, Finland
| | - Harri Piitulainen
- Faculty of Sport and Health Sciences, University of Jyväskylä, Jyväskylä, Finland.,Department of Neuroscience and Biomedical Engineering, Aalto University School of Science, Espoo, Finland.,Aalto NeuroImaging, Magnetoencephalography Core, Aalto University School of Science, Espoo, Finland
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