The construction of an experience of our own bodyown body · The construction of an experience of...

Collège de France, Feb 1st 2011Stanislas Dehaene Seminar

The construction of an experience of our own bodyown body

Henrik EhrssonD t t f N i K li k I tit t tDepartment of Neuroscience, Karolinska Institutet

Stockholm, Sweden

Body ownership y p

Whi h i h d?Which is my hand?

9 februari 2011Henrik Ehrsson 2

Asomatognosia andAsomatognosia and Somatoparaphrenia

Baier and Karnath (2008) St k

Arzy et al, . (2006) Arch Neurol

Stroke

B ti t l (2005) S i

9 februari 2011Henrik Ehrsson 3

Berti et al. (2005) Science

Body ownership as a’multisensory’ problemmultisensory problem

Whi h i h d?Which is my hand?

Henrik Ehrsson 9 februari 2011 4

OutlineOutline

1. Body ownership as a multisensory problemy p y p

2. Behavioural evidence from psychology

3. Multisensory responses in premotor and i t i t l h i l & i iintraparietal areas: neurophysiology & imaging

4 Imaging illusions of limb ownership4. Imaging illusions of limb ownership

5 Behavioural & imaging studies of full-body5. Behavioural & imaging studies of full-body ownership

6. Epilogue: applications to advanced prosthetics

1 Key principles of1. Key principles of multisensory integration

Henrik Ehrsson 9 februari 2011Stein and Stanford (2008) Nat Rev Neuroscience

Key principles ofKey principles of multisensory integration

• Temporal congruency principle.

• Spatial congruency principle.

• Principle of inverse effectiveness.

• Multisensory fusion problem.

M lti i t bl

• Multisensory assignment problem (causal interference problem)

H l d S (2005)

Henrik Ehrsson 9 februari 2011

Multisensory assignment problem From Körding et al. (2007)

Holmes and Spence (2005) Current Biolology

Body ownership as aBody ownership as a multisensory assignment problem

Seen &Felt hand Seen hand Felt hand

CVIS CTACCPRO CVIS CTAC

CPRO

Henrik Ehrsson 9 februari 2011

2. Behavioral evidence from experimental psychologyexperimental psychology

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Rubber hand illusion

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Botvinick and Cohen (1998) Nature 391: 756

Measures of the illusionMeasures of the illusion

• Questionnaire with visual analogue scales• Questionnaire with visual analogue scales. (Botvinick and Cohen 1998)

• Hand perceived closer to the location of the rubber hand (proprioceptive drift): pointing error when asked to point to one’s hand (error when asked to point to one s hand (e.g Taskiris and Haggard 2005; Ehrsson et al. 2005)

• Emotional responses when the hand is ‘threatened’ or ‘hurt’ (e.g Armel & Ramachandran 2003; Ehrsson et al 2009)2003; Ehrsson et al. 2009)

• Visual capture of tactile localization (cross p (modal congruency task) (Pavani et al 2001; Zopf et al. 2009)

Behavioural evidence that the illusion depends on integration of visual, tactile and proprioceptive information in hand-centered reference frame

Temporal congruency principle:

• The brushstrokes applied to the two hands must be synchronous (temporal congruency vision-touch)(Botvinick & Cohen 1998; Armel & Ramachandrantouch)(Botvinick & Cohen 1998; Armel & Ramachandran2003; Ehrsson et al. 2004; Tsakiris and Haggard 2005)

L t l d l b k th ill i (>300• Longer temporal delays break the illusion (>300 ms) (temporal congruency vision-touch)(Shimada et al. 2009)

Behavioural evidence that the illusion depends on integration of visual, tactile and proprioceptive information in hand-centered reference frame

Spatial congruency principle:

• The brushstrokes must be applied to corresponding parts of the two hands (spatial congruency vision-touch)(e.g. Ehrsson et al. 2009)

• The rubber hand must be anatomically aligned with the hidden real hand. (spatial congruency vision-proprioception) (Pavani et al. 2001; Ehrsson et al. 2004; Tsakiris et al. 2005)

Tsakiris et al. (2005)

Behavioural evidence that the illusion depends on integration of visual, tactile and proprioceptive information in hand-centered reference frame

Hand-centered reference frames:

• The rubber hand is placed within reaching distance (30 cm from the real hand) (Ll d 2007)hand) (Llyod 2007).

• The direction of the brushstrokes must congruent in hand-centered reference frames, and not in allocentric external coordinates (Constantini and Haggard 2007)

Lloyd (2008)

3 N h i l3. Neurophysiology: multisensory integration in y gpremotor and intraparietal cortex

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Multisensory neurons in premotor cortex and peri personal spacecortex and peri-personal space

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From Rizzolatti et al. (1981) Exp. Brain Res.

Multisensory neurons andMultisensory neurons and peri-personal space

Fogassi et al. (1996) J. Neurophysiol.Hyvärinen & Poranen 1974Rizzolatti et al. 1981Graziano & Gross 1993 1997

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Graziano & Gross 1993, 1997 Duhamel et al. 1998

M lti dMultisensory neurons and body-part-centered coordinates

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From Graziano et al. (1997, 1999)

Multisensory responses in premotor cortex in anethesized monkeysy

PMv

Adopted from Graziano et al. 1999, 2000Graziano et al. (2000) Exp. Brain Res. Graziano et al. (2007) J. Neurophysiol.

M lti i t ti i t lMultisensory integration in ventral intraparietal area: super-additivity

Henrik Ehrsson 9 februari 2011 20Avillac et al (2007) Nature Neuroscience

Multisensory integration in ventral y gintraparietal area: spatial and temporal congruency effectscongruency effects

Temporal congruency Spatial congruency

Henrik Ehrsson 9 februari 2011 21

Avillac et al (2007) Nature Neuroscience

Functional magnetic resonance imaging (fMRI)imaging (fMRI)

BOLD

sig

nal

B

Ownership measure

Bl d d d t i l (BOLD)9 februari 2011Henrik Ehrsson 22

• Blood-oxygen-dependent signal (BOLD)

Human premotor and intraparietal cortices

Di t i f th i ht h d

Human premotor and intraparietal cortices performs multisensory integration

Direct view of the right hand:X

From participant’s perspective

Tactile stimulation Visual stimulationperspective

Human premotor and intraparietal p pcortices performs multisensory integrationg

Henrik Ehrsson

Gentile et al. (2010) J. Neurophysiol

Human premotor and intraparietalHuman premotor and intraparietal cortices performs multisensory integrationintegration

Henrik EhrssonGentile et al. (2010) J. Neurophysiol

fMRI evidence for peripersonal space in

3 sec 3 sec

p p phuman premotor and intraparietal cortices

3 sec

3 sec

Inter-trial3-11 sec

NearNear 3 sec

3 sec

FarNear

3 11 secFar Far

NEARFAR

100 cm

HAND

NEAR≈ 2 cm

100 cm

NO HAND

FIXATION50 cm

Henrik Ehrsson Brozzoli et al. (In manuscript)

fMRI-adaptation evidence for peripersonal space in human premotor and intraparietal cortices

Near

First

Second

Near

Far

Brozzoli et al. (In manuscript)

fMRI-adaptation evidence for i l i hperipersonal space in human

premotor and intraparietal cortices

Brozzoli et al. (In manuscript)

4. Imaging illusions of body ownershipownership

Henrik Ehrsson 9 februari 2011

fMRI f bb h d ill ifMRI of rubber hand illusion

Ehrsson et al. (2004) Science

Illusion ratingsIllusion ratings7

5

6at

ing

S C

4

5

bjec

tive

ra Sync CongrAsync CongrSync IncongrAsync Incongr

2

3Sub

1Feeling thatthe rubberhand is my

Touch feelingis located onrubber hand

Real handturningrubbery

Real hand isdrifting

towards the

It seems thatI have more

than oneyhand

yrubber hand right hand

Interaction brushstroke-timing and arm orientation (F(1, 17)=14.22; p<0.005)

Ehrsson et al. (2004) Science

Experimental paradigmp p g

Ehrsson et al. (2004) Science

Premotor activity reflects feeling ofPremotor activity reflects feeling of ownership (superadditative effect)

Left and right ventral premotor cortex (p<0.05 corrected)g p (p )

Ehrsson et al. Science 305:875-7. 2004Ehrsson et al. (2004) Science

Parietal activity reflects congruent hand y gposition and synchrony (additative effect)

Conjuction of main effects of synchrony andConjuction of main effects of synchrony and anatomical congruency (p<0.001 corrected)

Ehrsson et al. Science 305:875-7. 2004Ehrsson et al. (2004) Science

C l ti b t ill iCorrelation between illusion ratings and premotor activityg p y

Ehrsson et al. Science 305:875-7. 2004Ehrsson et al. (2004) Science

Conclusion: multisensory integration in premotor and intraparietal areasin premotor and intraparietal areas reflect limb ownership

Seen &Seen &Felt hand

CVIS C CPRO

Botvinick (2004) Science

CTACPRO

9 februari 2011Henrik Ehrsson 36

Somatic rubber hand illusion illusion

R. precentral gyrus (45 -6 57)

Premotor cortexPremotor cortex

0.1

0.5

0.9

ontr

aste

stim

ates

(a.u

.)

L. Inf precentral s. (-60 9 9)

0.9ates

-0.3 Illusion Async Incogr

Condition

Co

Intraparietal cortex

-0.3

0.1

0.5

0.9

Illusion Async IncogrCon

tras

test

ima

(a.u

.)

2 10 6 3 200

Condition

Ehrsson et al. J Neurosci. 25:10564-73, 20059 februari 2011Henrik Ehrsson 37

Ehrsson et al. J Neurosci. 25:10564-73, 2005

Re-calibration of position sense

Botvinick and Cohen (1998) Nature

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Recalibration of position sense in aRecalibration of position sense in a ‘reaching circuit’ before illusion onset

Supplementary motor area, dorsal premotor cortex, th t i i t l t d th b llthe posterior parietal cortex, and the cerebellum

Henrik EhrssonEhrsson et al. (2004) Science

Objective evidence by th t i th bb h dthreatening the rubber hand

Ehrsson et al. (2007) PNAS 104:9828-9833 9 februari 2011Henrik Ehrsson 40

E i t l d iExperimental design

Eh t l (2007) PNAS 104 9828 9833Ehrsson et al. (2007) PNAS 104:9828-9833

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I d th t k dIncreased threat-evoked response when owning the hand

Insula ACC

(p<0.05 corrected) (p<0.05 corrected)

9 februari 2011Henrik Ehrsson 42Ehrsson et al. (2007) PNAS 104:9828-9833

Activity in multisensory areas predict the threat-evoked response

ivity

(a.u

.) em

otor

acti

L. Insula activity (parameter estimates)

L. P

re

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43

Ehrsson et al. (2007) PNAS

A preliminary model of limbA preliminary model of limb ownership

SMA, PMdHand-

S1 Processing of visual and tactile

signals in early sensory areas

PMvVisual areas

S1 Integration of visual and tactile

signals in posterior parietal cortex.

CB Recalibration of position sense in

motor regions.

Match of temporally and spatially congruent multisensory signals in premotor cortex (PMv) producepremotor cortex (PMv) produce ownership

Changes in other brain systems, e.g. in th ti l t

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the emotional system

Three-arm-illusion: k bl f t tia remarkable case of construction

Henrik Ehrsson 9 februari 2011 45

Ehrsson (2009) Perception 38, 310-312

Objective evidencej

Henrik Ehrsson 9 februari 2011 46

Ehrsson (2009) Perception 38, 310-312

Three-arm-illusion: k bl f t tia remarkable case of construction

50%50%

Seen &Felt hand

Seen &Felt hand

CVIS CTACCPRO

9 februari 2011

Henrik Ehrsson 9 februari 2011 47

Ehrsson (2009) Perception 38, 310-312

5. Extending the model to ownership of entire bodiesownership of entire bodies

O t f b d i (F B 2002)

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Out-of-body experiences (From Brugger 2002)

Neurological out-of-body experiencesNeurological out of body experiences

Illusory body

Blanke et al. (2000) Nature Physical body

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Blanke et al. (2002) Nature; Blanke and Mohr (2005) Brain Res. Reviews

First-person perspective and body ownershipbody ownership

Gibbson (1972) The ecological approach to visual perception (1972)

Ernst Mach (1885) Analyse der Empfindungento visual perception (1972)

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Analyse der Empfindungen

Out-of-body illusion

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Ehrsson (2007) Science 317: 1048

Experimental evidence

BA

Registration of skin conductance response (SCR)

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Ehrsson (2007) Science

Ownership of an entire bodyOwnership of an entire body other than oneself

P tk & Eh t l PL S O (2008)

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Petkova & Ehrsson et al. PLoS One (2008)

Obj ti t t Ski C d t RObjective test: Skin Conductance Responseo-

oho) Knife (Sync) Spoon (Sync) Knife (Async)

SCR

(mic

ro

Time (s)

Generalization of ownership to non stimulated body partsto non-stimulated body parts

1. Brush hand 2. Cut BellyKey experimental test:

SyncHand

AsyncHand

SyncBelly

AsyncBelly

559 februari 2011Henrik Ehrsson

Petkova & Ehrsson (2008) PLoS ONE

Effect of humanoid body shape

S A S ASyncBody

AsyncBody

SyncWood

AsyncWood

Petkova & Ehrsson PLoS One (2008)

Effect of visual perspective

First-person-tiperspective

(1PP)

Third-person-perspective

(3PP)

1PPSync

1PPAsync

3PPSync

3PPAsync

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Petkova et al. In revision Frontiers in Cogntion

The illusion can be induced without video-technology, but only from the first-person perspective

1PP 3PP

p p p

Khoshnevis, Petkova & Ehrsson, in preparation, 2009Petkova et al. In revision Frontiers in Cognition

The illusion can be induced without video-technology, but only from the first-person perspective p p p

1PP SCR

3PP

IPPSync

IPPAsync

3PPSync

3PPAsync

Khoshnevis, Petkova & Ehrsson, in preparation, 2009

Sync Async Sync Async

Petkova et al. In revision Frontiers in Cognition

Imaging the full-body illusion:Imaging the full body illusion: Object x Timing

9 februari 2011Henrik Ehrsson 60Petkova et al. (submitted)

Interaction effect (Body X Sync)Interaction effect (Body X Sync)

I i h f ll b d ill iImaging the full-body illusion:Perspective x Timingg

Sync1-PP

Async1-PP

hird

PP

Sync AsyncPP

T

h

3-PP 3-PP

Firs

t

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62

Petkova et al. (submitted)

Interaction effect (1PP X Sync)Interaction effect (1PP X Sync)

C l ti b t ill i t th dCorrelation between illusion strength and interaction BOLD effect

Imaging the full-body illusion: G li ti f hiGeneralisation of ownership across body parts

Timing

Sync1 PPne

quin

AsyncB ll

SyncB ll

Timing

AyncB ll1-PP

rt on

man BellyBelly

Manne

Belly

Bod

y pa Sync

1-PPSyncHand

AsyncHand

equin’s ha

Sync1-PP

SyncDetachedHand

AsyncDetachedHand

nd vs detaHand Hand ached han

Henrik Ehrsson

nd

Petkova et al. (submitted)

B d t ifi d b d t lBody-part specific and body-part general activations

Body-part specific and body-part generalBody-part specific and body-part general activations

Graziano et al. (2000) Exp Brain ResPetkova et al. (submittted)

Hand attached to mannequin Vs detachedHand attached to mannequin Vs detached hand (interaction effect)

Petkova et al. (submitted)

Generalization of ownership between body-specifc sections

Interaction (manniquin’s hand / detatched hand X Timing)

I t i l iInterim conclusion: ownerhship of entire bodies

Visual information from the first-person perspective, in conjunction with spatially and temporally congruent tactile, proprioceptiveand visual signals in ego-centric reference frames are necessary and sufficient factors elicit a sense of ownership of an entire body.

Our fMRI results suggest that the key neural mechanism is the integration of visual and somatic signals in body-part-centred

f f b lti l l ti ireference frames by multisensory neuronal populations in premotor and intraparietal cortex.

Importantly, these multisensory mechanisms operate in parallelfor different body parts with functional interplay between theseprocessesprocesses.

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6. Applications: simulated bodies and advanced prostheticsand advanced prosthetics

Henrik Ehrsson 9 februari 2011

Projecting ownership to virtual bodies

Slater et al. (PLOS ONE 2010)( ) Jesper Mortensen, Pankaj Khanna, Insu Yu,

Bernhard Spanlang, Mel Slater EPSRC 'Presence in the Virtual Light Field' and FET PRESENCCIA.

Henrik Ehrsson 9 februari 2011 72

Humanoid robotic hand prostheses

SMART hand project (6FP project coordinated from University of Lund; Fredrik Sebelius Dept. Electrical Measurements, Lund University)Fredrik Sebelius Dept. Electrical Measurements, Lund University)

“the PISA hand” - developed and provided by the ARTS Lab, Scuola Superiore Sant´Anna (IST-2001-35094)

Henrik Ehrsson 9 februari 2011 73

p ( )

Upper limb amputees can be induced to e perience a r bber hand as their o nexperience a rubber hand as their own

Ehrsson HH Rosén B Stockselius A Ragnö C Rosen et al (2009) Scand J

Henrik Ehrsson 9 februari 2011 74

Ehrsson HH, Rosén B, Stockselius A, Ragnö C, Köhler P, Lundborg G (2008) Brain 131, 3443-3452

Rosen et al. (2009) Scand J Plast Reconstr Surg Hand

Surg. 43:260-266

Upper limb amputees can be induced to experience a rubber hand as their ownexperience a rubber hand as their own

Henrik Ehrsson 9 februari 2011 75Ehrsson et al. (2008) Brain 131, 3443-3452

SummarySummary• The problem of body ownership can be explained within

a multisensory framework

• The natural constraints of the rubber hand illusion and

a multisensory framework.

• The natural constraints of the rubber hand illusion and full-body illusions obey multisensory integration principles.

• Activity in premotor and intraparietal cortex obeys the ‘multisensory rules’ of the body ownership illusions; thusmultisensory rules of the body ownership illusions; thus multisensory integration in body-part-centered coordinates is a likely mechanism of ownership.

• By employing the multisensory principles of body ownership one can create a new type of arm prosthesis

9 februari 2011Henrik Ehrsson 76

ownership one can create a new type of arm-prosthesis that feels more like a real limb.

Brain, Body and Self Laboratory Dr. Alexander Skoglund, research

engineer

Dr. Hiske van Duinen, postdoc

Dr. Claudio Brozzoli, postdoc

Dr. Loretxu Bergouignan, postdoc

Dr Laura Schmalzl postdocDr. Laura Schmalzl, postdoc

Valeria Petkova, PhD student.

Giovanni Gentile, PhD student

Andreas Kalckert, PhD student.

htt // ki / h /

,

Arvid Guterstam PhD student

9 februari 2011

http://www.neuro.ki.se/ehrsson/Björn van der Hoort, Hedvig Zetterberg and Chris Berger (master students) Postdoc positions open!

Thank you!

http://www neuro ki se/ehrsson/http://www.neuro.ki.se/ehrsson/Henrik Ehrsson 9 februari 2011 78