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Graham M. Residual Cognitive Capacities in Patients With Cognitive Motor Dissociation, and Their Implications for Well-Being. THE JOURNAL OF MEDICINE AND PHILOSOPHY 2021; 46:729-757. [PMID: 34655220 PMCID: PMC8643594 DOI: 10.1093/jmp/jhab026] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Patients with severe disorders of consciousness are thought to be unaware of themselves or their environment. However, research suggests that a minority of patients diagnosed as having a disorder of consciousness remain aware. These patients, designated as having “cognitive motor dissociation” (CMD), can demonstrate awareness by imagining specific tasks, which generates brain activity detectable via functional neuroimaging. The discovery of consciousness in these patients raises difficult questions about their well-being, and it has been argued that it would be better for these patients if they were allowed to die. Conversely, I argue that CMD patients may have a much higher level of well-being than is generally acknowledged. It is far from clear that their lives are not worth living, because there are still significant gaps in our understanding of how these patients experience the world. I attempt to fill these gaps, by analyzing the neuroscientific research that has taken place with these patients to date. Having generated as comprehensive a picture as possible of the capacities of CMD patients, I examine this picture through the lens of traditional philosophical theories of well-being. I conclude that the presumption that CMD patients do not have lives worth living is not adequately supported.
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Coulborn S, Taylor C, Naci L, Owen AM, Fernández-Espejo D. Disruptions in Effective Connectivity within and between Default Mode Network and Anterior Forebrain Mesocircuit in Prolonged Disorders of Consciousness. Brain Sci 2021; 11:749. [PMID: 34200092 PMCID: PMC8227204 DOI: 10.3390/brainsci11060749] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Revised: 05/25/2021] [Accepted: 05/30/2021] [Indexed: 11/17/2022] Open
Abstract
Recent research indicates prolonged disorders of consciousness (PDOC) result from structural and functional impairments to key cortical and subcortical networks, including the default mode network (DMN) and the anterior forebrain mesocircuit (AFM). However, the specific mechanisms which underpin such impairments remain unknown. It is known that disruptions in the striatal-pallidal pathway can result in the over inhibition of the thalamus and lack of excitation to the cortex that characterizes PDOC. Here, we used spectral dynamic causal modelling and parametric empirical Bayes on rs-fMRI data to assess whether DMN changes in PDOC are caused by disruptions in the AFM. PDOC patients displayed overall reduced coupling within the AFM, and specifically, decreased self-inhibition of the striatum, paired with reduced coupling from striatum to thalamus. This led to loss of inhibition from AFM to DMN, mostly driven by posterior areas including the precuneus and inferior parietal cortex. In turn, the DMN showed disruptions in self-inhibition of the precuneus and medial prefrontal cortex. Our results provide support for the anterior mesocircuit model at the subcortical level but highlight an inhibitory role for the AFM over the DMN, which is disrupted in PDOC.
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Affiliation(s)
- Sean Coulborn
- Centre for Human Brain Health and School of Psychology, University of Birmingham, Birmingham B15 2TT, UK; (S.C.); (C.T.)
| | - Chris Taylor
- Centre for Human Brain Health and School of Psychology, University of Birmingham, Birmingham B15 2TT, UK; (S.C.); (C.T.)
| | - Lorina Naci
- Trinity College Institute of Neuroscience, School of Psychology, Trinity College Dublin, D02 PN40 Dublin, Ireland;
| | - Adrian M. Owen
- Brain and Mind Institute, Western University, London, ON N6A 5B7, Canada;
| | - Davinia Fernández-Espejo
- Centre for Human Brain Health and School of Psychology, University of Birmingham, Birmingham B15 2TT, UK; (S.C.); (C.T.)
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Pace-Schott EF, Amole MC, Aue T, Balconi M, Bylsma LM, Critchley H, Demaree HA, Friedman BH, Gooding AEK, Gosseries O, Jovanovic T, Kirby LA, Kozlowska K, Laureys S, Lowe L, Magee K, Marin MF, Merner AR, Robinson JL, Smith RC, Spangler DP, Van Overveld M, VanElzakker MB. Physiological feelings. Neurosci Biobehav Rev 2019; 103:267-304. [DOI: 10.1016/j.neubiorev.2019.05.002] [Citation(s) in RCA: 80] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Revised: 03/27/2019] [Accepted: 05/03/2019] [Indexed: 12/20/2022]
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Stafford CA, Owen AM, Fernández-Espejo D. The neural basis of external responsiveness in prolonged disorders of consciousness. Neuroimage Clin 2019; 22:101791. [PMID: 30991612 PMCID: PMC6447738 DOI: 10.1016/j.nicl.2019.101791] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2018] [Revised: 02/03/2019] [Accepted: 03/24/2019] [Indexed: 01/18/2023]
Abstract
OBJECTIVE To investigate the structural integrity of fibre tracts underlying overt motor behaviour in PDOC. METHODS This cross-sectional study examined 15 PDOC patients and 22 healthy participants. Eight PDOC patients met the criteria for the vegetative state, 5 met the criteria for the minimally conscious state and 2 met the criteria for emerging from the minimally conscious state. We used fibre tractography to reconstruct the white matter fibres known to be involved in voluntary motor execution (i.e., those connecting thalamus with M1, M1 with cerebellum, and cerebellum with thalamus) and used fractional anisotropy (FA) as a measure of their integrity. RESULTS PDOC patients showed significantly reduced FA relative to controls on the fibres connecting thalamus and M1. This went above and beyond a widespread injury to the white matter and correlated with clinical severity. In a subset of patients, we also identified a similar pattern of injury in the fibres connecting M1 and cerebellum but a relative preservation of those connecting cerebellum and thalamus. CONCLUSIONS Our results suggest that structural damage to motor fibres may lead to reduced responsiveness in PDOC patients across all diagnostic sub-categories, and therefore behavioural assessments may underestimate the level of retained cognitive function and awareness across the PDOC spectrum.
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Affiliation(s)
- Clara A Stafford
- Brain and Mind Institute, Department of Psychology, The University of Western Ontario, London, Ontario N6C 5B7, Canada
| | - Adrian M Owen
- Brain and Mind Institute, Department of Psychology, The University of Western Ontario, London, Ontario N6C 5B7, Canada
| | - Davinia Fernández-Espejo
- School of Psychology, The University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom; Centre for Human Brain Health, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom.
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Rosso MPDO, Rosa Júnior GM, Buchaim DV, German IJS, Pomini KT, de Souza RG, Pereira M, Favaretto Júnior IA, Bueno CRDS, Gonçalves JBDO, Ferreira Júnior RS, Barraviera B, Andreo JC, Buchaim RL. Stimulation of morphofunctional repair of the facial nerve with photobiomodulation, using the end-to-side technique or a new heterologous fibrin sealant. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2017; 175:20-28. [PMID: 28846931 DOI: 10.1016/j.jphotobiol.2017.08.023] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2017] [Revised: 08/13/2017] [Accepted: 08/17/2017] [Indexed: 12/01/2022]
Abstract
This research evaluated the influence of Photobiomodulation Therapy (PBMT) on lesions of the facial nerve repaired with the end-to-side technique or coaptation with a new heterologous fibrin sealant. Thirty-two Wistar rats were separated into 5 groups: Control group (CG), where the buccal branch of the facial nerve was collected; Experimental Suture Group (ESG) and Experimental Fibrin Group (EFG), in which the buccal branch was end-to-side sutured to the zygomatic branch on the right side of the face or coaptated with fibrin sealant on the left side; Experimental Suture Laser Group (ESLG) and Experimental Fibrin Laser Group (EFLG), in which the same procedures were performed as the ESG and EFG, associated with PBMT (wavelength of 830nm, energy density 6.2J/cm2, power output 30mW, beam area of 0.116cm2, power density 0.26W/cm2, total energy per session 2.16J, cumulative dose of 34.56J). The laser was applied for 24s/site at 3 points on the skin's surface, for a total application time of 72s, performed immediately after surgery and 3 times a week for 5weeks. A statistically significant difference was observed in the fiber nerve area between the EFG and EFLG (57.49±3.13 and 62.52±3.56μm2, respectively). For the area of the axon, fiber diameter, axon diameter, myelin sheath area and myelin sheath thickness no statistically significant differences were found (p<0.05). The functional recovery of whisker movement occurred faster in the ESLG and EFLG, which were associated with PBMT, with results closer to the CG. Therefore, PBMT accelerated morphological and functional nerve repair in both techniques.
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Affiliation(s)
| | | | | | - Iris Jasmin Santos German
- Department of Biological Sciences (Anatomy), Bauru School of Dentistry, University of São Paulo (USP), Bauru, SP, Brazil
| | - Karina Torres Pomini
- Department of Biological Sciences (Anatomy), Bauru School of Dentistry, University of São Paulo (USP), Bauru, SP, Brazil
| | - Rafael Gomes de Souza
- Human Morphophysiology (Anatomy), University of Marilia (UNIMAR), Marilia, SP, Brazil
| | - Mizael Pereira
- Department of Biological Sciences (Anatomy), Bauru School of Dentistry, University of São Paulo (USP), Bauru, SP, Brazil
| | | | | | | | - Rui Seabra Ferreira Júnior
- Center for the Study of Venoms and Venomous Animals (CEVAP), São Paulo State University (Univ. Estadual Paulista, UNESP), Botucatu, SP, Brazil
| | - Benedito Barraviera
- Center for the Study of Venoms and Venomous Animals (CEVAP), São Paulo State University (Univ. Estadual Paulista, UNESP), Botucatu, SP, Brazil
| | - Jesus Carlos Andreo
- Department of Biological Sciences (Anatomy), Bauru School of Dentistry, University of São Paulo (USP), Bauru, SP, Brazil
| | - Rogério Leone Buchaim
- Department of Biological Sciences (Anatomy), Bauru School of Dentistry, University of São Paulo (USP), Bauru, SP, Brazil; Human Morphophysiology (Anatomy), University of Marilia (UNIMAR), Marilia, SP, Brazil
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