Abstract
A major challenge in the diagnosis of disorders of consciousness is the differential diagnosis between the vegetative state (VS) and the minimally conscious state (MCS). Clinically, VS is defined by complete unawareness, whereas MCS is defined by the presence of inconsistent but clearly discernible behavioural signs of consciousness. In healthy individuals, pain cries have been reported to elicit functional activation within the pain matrix of the brain, which may be interpreted as empathic reaction. In this study, pain cries were presented to six VS patients, six MCS patients, and 17 age-matched healthy controls. Conventional task-related functional magnetic resonance imaging (fMRI) showed no significant differences in functional activation between the VS and MCS groups. In contrast to this negative finding, the application of a novel data-driven technique for the analysis of the brain’s global functional connectivity yielded a positive result. The weighted global connectivity (WGC) was significantly greater in the MCS group compared to the VS group (p < 0.05, family-wise error corrected). Using areas of significant WGC differences as ‘seed regions’ in a secondary connectivity analysis revealed extended functional networks in both MCS and healthy groups, whereas no such long-range functional connections were observed in the VS group. These results demonstrate the potential of functional connectivity MRI (fcMRI) as a clinical tool for differential diagnosis in disorders of consciousness.
Similar content being viewed by others
References
Andrews K, Murphy L, Munday R, Littlewood C (1996) Misdiagnosis of the vegetative state: retrospective study in a rehabilitation unit. Br Med J 313:13–16
Avenanti A, Bueti D, Galati G, Aglioti SM (2005) Transcranial magnetic stimulation highlights the sensorimotor side of empathy for pain. Nat Neurosci 8:955–960
Baars BJ (1988) A cognitive theory of consciousness. Cambridge University Press Cambridge, UK
Baars BJ (1997) In the theater of consciousness. Oxford University Press, Oxford, UK
Bekinschtein TA, Shalom DE, Forcato C, Herrera M et al (2009) Classical conditioning in the vegetative and minimally conscious state. Nat Neurosci 12:1343–1349
Benuzzi F, Lui F, Duzzi D, Nichelli PF, Porro CA (2008) Does it look painful or disgusting? Ask your parietal and cingulate cortex. J Neurosci 28:923–931
Block N (2007) Consciousness, accessibility, and the mesh between psychology and neuroscience. Behav Brain Sci 30:481–499
Boly M, Faymonville ME, Peigneux P, Lambermont B, Damas P, Del Fiore G, Degueldre C, Franck G, Luxen A, Lamy M, Moonen G, Maquet P, Laureys S (2004) Auditory processing in severely brain injured patients: differences between the minimally conscious state and the persistent vegetative state. Arch Neurol 61:233–238
Boly M, Phillips C, Tshibanda L, Vanhaudenhuyse A, Schabus M, Dang-Vu T, Moonen G, Hustinx R, Maquet P, Laureys S (2008) Intrinsic brain activity in altered states of consciousness: how conscious is the default mode of brain function? Ann N Y Acad Sci 1129:119–129
Boly M, Tshibanda L, Vanhaudenhuyse A, Noirhomme Q, Schnakers C, Ledoux D, Boveroux P, Garweg P, Lambernmont B, Phillips C, Luxen A, Moonen G, Bassetti C, Maquet P, Laureys S (2009) Functional connectivity in the default network during resting state is preserved in a vegetative but not in a brain dead patient. Hum Brain Mapp 30:2393–2400
Boly M, Garrido MI, Gossieres O, Bruno M-A, Boveroux P, Schnakers C, Massimini M, Litvak V, Laureys S, Friston KJ (2011) Preserved feedforward but impaired top-down processes in the vegetative state. Science 332:858–862
Bradley MM, Lang PJ (1999). International Affective Digitized Sounds (IADS): Stimuli, instruction manual and affective ratings. Technical report B-2: The Center for Research in Psychophysiology, University of Florida
Brooks J, Tracey I (2005) From nociception to pain perception: imaging the spinal and supraspinal pathways. J Anat 207:19–33
Calhoun VD, Pearlson GD (2012) A selective review of simulated driving studies: combining naturalistic and hybrid paradigms, analysis approaches, and future directions. Neuroimage 59:25–35
Cole MW, Pathak S, Schneider W (2010) Identifying the brain’s most globally connected regions. Neuroimage 49:3132–3148
Damasio AR (1999) The feeling of what happens: body and emotion in the making of consciousness. Harcourt, San Diego, USA
Dehaene S, Changeaux JP, Naccache L, Sackur J, Sergent C (2006) Conscious, preconscious, and subliminal processing: a testable taxonomy. Trends Cogn Sci 10:204–211
Friston KJ, Holmes AP, Worsley KJ, Poline JP, Frith CD, Frackowiak RSJ (1995) Statistical parametric maps in functional imaging: a general linear approach. Hum Brain Mapp 2:189–210
Giacino JT, Ashwal S, Childs N, Cranford R, Jennett B, Katz DI, Kelly JP, Rosenberg JH, Whyte J, Zafonte RD, Zasler ND (2002) The minimally conscious state. Definition and diagnostic criteria. Neurology 58:349–353
Giacino JT, Kalmar K, Whyte J (2004) The JFK Coma Recovery Scale-Revised: measurement characteristics and diagnostic utility. Arch Phys Med Rehabil 85:2020–2029
Gu X, Han S (2007) Attention and reality constraints on the neural processes of empathy for pain. Neuroimage 36:256–267
Kotchoubey B (2009). Vegetative state. In: Squire L (ed) Encyclopedia of neuroscience, vol 10. Elsevier, Amsterdam, p 61–66
Kotchoubey B, Yu T, Markl A, Vogel D, Müller F, Lang S (2011) On the way to the deep layers of consciousness. Adv Clin Neurosci Rehabil 11:10–13
Lang S, Yu T, Markl A, Müller F, Kotchoubey B (2011) Hearing others’ pain: neural activity related to empathy. Cogn Affect Behav Neurosci 11:386–395
Laureys S, Goldman S, Phillips C, Van Bogaert P, Aerts J, Luxen A, Franck G, Maquet P (1999) Impaired effective cortical connectivity in vegetative state: preliminary investigation using PET. Neuroimage 9:377–382
Laureys S, Faymonville ME, Luxen A, Lamy M, Franck G, Maquet P (2000) Restoration of thalamocortical connectivity after recovery from persistent vegetative state. The Lancet 355:1790–1791
Laureys S, Faymonville ME, Peigneux P, Damas P, Lambermont B, Del Fiore G, Degueldre C, Maquet P (2002) Cortical processing of noxious somatosensory stimuli in the persistent vegetative state. Neuroimage 17:732–741
Laureys S (2005) Death, unconsciousness and the brain. Nat Rev Neurosci 6:899–909
Lohmann G, Margulies DS, Horstmann A, Pleger B, Lepsien J, Goldhahn D, Schloegl H, Stumvoll M, Villringer A, Turner R (2010) Eigenvector centrality mapping for analyzing connectivity patterns in fMRI data of the human brain. PLoS ONE 5:1–8
Moriguchi Y, Decety J, Ohnishi T, Maeda M, Mori T, Nemoto K, Matsuda H, Komaki G (2007) Empathy and judging other’s pain: an fMRI study of alexithymia. Cereb Cortex 17:2223–2234
Moulton EA, Schmahmann JD, Becerra L, Borsook D (2010) The cerebellum and pain: passive integrator or active participator? Brain Res Rev 65:14–27
Nichols T, Hayasaka S (2003) Controlling the familywise error rate in functional neuroimaging: a comparative review. Stat Methods Med Res 12:419–446
Nichols TE, Holmes AP (2002) Nonparametric permutation tests for functional neuroimaging: a primer with examples. Hum Brain Mapp 15:1–25
Panksepp J (2005) Affective consciousness: core emotional feelings in animals and humans. Conscious Cogn 14:30–80
Peltier SJ, Kerssens C, Hamann SB, Sebel PS, Byas-Smith M, Hu X (2005) Functional connectivity changes with concentration of sevoflurane anesthesia. NeuroReport 16:285–288
Perrin JS, Merz S, Bennett DM, Currie J, Steele DJ, Reid IC, Schwarzbauer C (2012) Electroconvulsive therapy reduces frontal cortical connectivity in severe depressive disorder. Proc Natl Acad Sci 109:5464–5468
Sander K, Frome Y, Scheich H (2007) FMRI activations of amygdala, cingulate cortex, and auditory cortex by infant laughing and crying. Hum Brain Mapp 18:1007–1022
Schnakers C, Vanhaudenhuyse A, Giacino J, Ventura M, Boly M, Majerus S, Moonen G, Laureys S (2009) Diagnostic accuracy of the vegetative and minimally conscious state: clinical consensus versus standardized neurobehavioral assessment. BMC Neurology 9, Article 35
Singer T, Seymour B, O’Doherty JP, Kaube H, Dolan RJ, Frith CD (2004) Empathy for brain involves the affective but not sensory components of pain. Science 303:1157–1162
Tononi G (2008) Consciousness as integrated information: a provisional manifesto. Biol Bull 215:216–242
Acknowledgments
CS would like to thank the Chief Scientist Office of Scotland for partly funding this research. SM and CS acknowledge the support of the Scottish Funding Council (SFC) through the SINAPSE initiative (Scottish Imaging Network: A Platform for Scientific Excellence; http://www.sinapse.ac.uk). BK, SL, AM, FM and TY were supported by the German Research Society (Deutsche Forschungsgemeinschaft, DFG). In addition BK acknowledges the support from the European Union (Grant DECODER).
Ethics standard statement
The study was approved by the local ethics committee.
Conflicts of Interest
None.
Author information
Authors and Affiliations
Corresponding author
Additional information
B. Kotchoubey and S. Merz contributed equally to this work.
Rights and permissions
About this article
Cite this article
Kotchoubey, B., Merz, S., Lang, S. et al. Global functional connectivity reveals highly significant differences between the vegetative and the minimally conscious state. J Neurol 260, 975–983 (2013). https://doi.org/10.1007/s00415-012-6734-9
Received:
Revised:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s00415-012-6734-9