Mertens, Yoki Linn

English

Peritraumatic dissociation, e.g. an out-of-body experience (OBE) during a traumatic event, is an established risk factor for post-traumatic stress disorder (PTSD). However, its neural basis is not yet well understood. Experimental neuroscience and lesion studies suggest that disrupted brain function in the temporo-parietal junction (TPJ), a critical hub for multisensory integration, is associated with such anomalous bodily experiences. To explore neural markers of disrupted embodiment, we investigated how a transcranial magnetic stimulation (TMS)-induced temporary inhibition of the TPJ affects 1) dissociative experiencing including susceptibility to OBEs, and 2) the brain network of body awareness in healthy participants. First, we tested the paradigm to manipulate bodily self-consciousness called the OBE illusion and threat-evoked changes in heart rate as objective marker of OBEs. Secondly, functional connectivity ! patterns and the OBE paradigm were assessed before and after TMS (n = 26) vs. sham TMS (n = 26). It was expected that a virtual lesion at the TPJ increases self-report dissociation, elicit stronger OBE sensations, and disrupt the brain network of body awareness (e.g. insula, posterior parietal cortex, premotor cortex). Results will be discussed within the framework of dissociative processing

Dissertations of the University of Groningen

   University of GroningenThe disembodied selfMertens, Yoki LinnIMPORTANT NOTE: You are advised to consult the publisher's version (publisher's PDF) if you wish to cite fromit. Please check the document version below.Publication date:2019Link to publication in University of Groningen/UMCG research databaseCitation for published version (APA):Mertens, Y. L. (2019). The disembodied self: Using an experimental approach to study the neuralcorrelates of dissociation. Poster session presented at 35th Annual Meeting of the International Society forTraumatic Stress Studies (ISTSS), Boston, United States.CopyrightOther than for strictly personal use, it is not permitted to download or to forward/distribute the text or part of it without the consent of theauthor(s) and/or copyright holder(s), unless the work is under an open content license (like Creative Commons).The publication may also be distributed here under the terms of Article 25fa of the Dutch Copyright Act, indicated by the “Taverne” license.More information can be found on the University of Groningen website: https://www.rug.nl/library/open-access/self-archiving-pure/taverne-amendment.Take-down policyIf you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediatelyand investigate your claim.Downloaded from the University of Groningen/UMCG research database (Pure): http://www.rug.nl/research/portal. For technical reasons thenumber of authors shown on this cover page is limited to 10 maximum.Download date: 05-06-2022Background The Disembodied Self –  Using an experimental approach to investigate objective markers of dissociation Yoki L. Mertens1,2, Judith K. Daniels1, André Aleman1,2 1University of Groningen 2Cognitive Neuroimaging Centre, University Medical Centre Groningen  -  Individuals with childhood trauma report elevated levels of  dissociation, e.g. depersonalization symptoms1. -  Lack of objective markers of (somatoform) dissociation, e.g. out-of-body experiences (OBEs; Picture 2).  -  Reduced sense of of self and diminished body awareness could relate to brain deficits in integrative capacity.  -  The temporoparietal junction (TPJ; Picture 1), a critical hub for multisensory integration, is a proposed key region for establishing a coherent sense of (bodily) self2,3.  -  Lesion and perturbation studies indicate that stimulation of the TPJ affects own-body perceptions4,5 and decreases depersonalization symptoms6.  -  Connectivity between right TPJ and right (posterior) insula depicted the strongest activity associated with changes in self-location and first-person perspective7.         Picture 1. The temporoparietal junction.4 How does a temporary perturbation of the right temporoparietal junction (rTPJ) affect  1)  Dissociative experiences in individuals with (and without) a history of childhood trauma  2) Experimentally-induced OBEs8?  3) The brain network subserving body awareness?   Research Question Methods Study Design: Sham-controlled, randomized, pre-post TMS study Study Population: Total N = 52 right-handed, female, young adults* Trauma Group: N = 26 subjects with former childhood trauma Control Group: N = 26 subjects without former childhood trauma  *Exclusion Criteria 1) Neurological disorder, e.g. epilepsy 2) Psychiatric disorder 3) Presence of metallic devices 4) Psychotropic medication intake for the last 6 months 5) Claustrophobia 6) Alcohol or drug abuse 7) Tinnitus Transcranial Magnetic Stimulation (TMS) •  cTBS protocol, 40s, 600 pulses •  Inhibitory effect •  Neuronavigated rTPJ stimulation  (Brain Voyager TMS neuronavigation) Out-of-Body Illusion Paradigm8 PRE-TMS •  VR goggles connected to camera filming subject •  Synchronous tapping à OBE Out-of-Body Illusion Paradigm8 POST-TMS •  VR goggles connected to camera filming subject •  Synchronous tapping à OBE 1 2 3 Brain network PRE-TMS •  Anatomical scan •  Resting-state fMRI  •  Functional connectivity analyses (CONN toolbox, SPM12; ROIs: TPJ, insula, pSTG, S1, mPFC,..)  4 5 Brain network POST-TMS •  Resting-state fMRI •  Functional connectivity analyses (CONN toolbox, SPM12; ROIs: TPJ, insula, pSTG, S1, mPFC,..)    •  Measured with wireless C3 Cortrium heart rate (HR) monitor •  Threat-evoked: Fake hammer attack on illusory body •  Before: Increased emotional distress measured via skin conductance response after OBE induction8 •  Hypothesis: OBE induction leads to increased heart rate (=distress) when illusory body attacked.  Infobox 1:  Heart rate as objective marker of disembodiment •  Subjects indicate shift in self-localization on map •  Hypothesis: OBE induction leads to shift in self-localization from original position (smiley) towards camera (red triangle) Questionnaires References 1Vonderlin, R., Kleindienst, N., Alpers, G. W., Bohus, M., Lyssenko, L., & Schmahl, C. (2018). Dissociation in victims of childhood abuse or neglect: a meta-analytic review. Psychological medicine, 48(15), 2467-2476. 2Eddy, C. M. (2016). The junction between self and other? Temporo-parietal dysfunction in neuropsychiatry. Neuropsychologia, 89, 465-477. 3Blanke, O. (2012). Multisensory brain mechanisms of bodily self-consciousness. Nature Reviews Neuroscience, 13(8), 556. 4Donaldson, P. H., Rinehart, N. J., & Enticott, P. G. (2015). Noninvasive stimulation of the temporoparietal junction: A systematic review. Neuroscience & Biobehavioral Reviews, 55, 547-572. 5Grivaz, P., Blanke, O., & Serino, A. (2017). Common and distinct brain regions processing multisensory bodily signals for peripersonal space and body ownership. Neuroimage, 147, 602-618. 6Jay, E. L., Sierra, M., Van den Eynde, F., Rothwell, J. C., & David, A. S. (2014). Testing a neurobiological model of depersonalization disorder using repetitive transcranial magnetic stimulation. Brain stimulation, 7(2), 252-259. 7Ionta, S., Martuzzi, R., Salomon, R., & Blanke, O. (2014). The brain network reflecting bodily self-consciousness: a functional connectivity study. Social cognitive and affective neuroscience, 9(12), 1904-1913. 8Ehrsson, H. H. (2007). The experimental induction of out-of-body experiences. Science, 317(5841), 1048-1048. Contact  Yoki Linn Mertens, PhD student Department: Clinical Psychology & Experimental Psychopathology; University of Groningen, Netherlands  E-mail: y.l.mertens@rug.nl Phone: +31 50363 7373 Childhood Trauma. Childhood Trauma Questionnaire (CTQ; Bernstein & Fink, 1998) State Dissociation.  Dissociation Tension Scale – Short (DSS-4; Stiglmayr et al., 2009) Trait Dissociation. Dissociative Experiences Scale (DES-II; Carlson & Putnam, 2000) Depersonalization. Cambridge Depersonalization Scale (CDS; Sierra & Berrios, 2000) Vestibular Symptoms. Vertigo Symptom Scale-Short Form (VSS-SF; Wilhelmsen et al., 2008) Sleep Quality. Pittsburgh Sleep Quality Index (PSQI; Buysse et al., 1989)  Infobox 2:   Spatial map as objective marker  of self-localization TMS Coil (Figure-8; Cool B65; MagVenture) Picture 2. Out-of-Body Experience3 

The disembodied self:Using an experimental approach to study the neural correlates of dissociation

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The disembodied self:Using an experimental approach to study the neural correlates of dissociation

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