Ecole Polytechnique Fédérale de Lausanne

Multisensory brain mechanisms of bodily self-consciousness

Olaf Blanke

http://lnco.epfl.ch/ Laboratory of Cognitive Neuroscience http://cnp.epfl.ch/

Center for Neuroprosthetics

What is a Self ?

The self seems distinct

from the environment and other humans and may be

described as an entity to which certain mental

events and actions are ascribed. [David &

Kircher, 2003]

Autobiographical Memory

Thought: Cogito Ergo Sum

Visual Mirror Recognition

The Self in Cognitive Neuroscience

Bodily self-consciousness: How the brain processes signals from the body is the foundation for the self

Jeannerod, Frith, Ramachandran Damasio, Craig

Bodily self (consciousness) without a body Phantom limbs

[Halligan, 2002; Melzack, 1990; Ramachandran, 1993; Brugger et al., 2000]

The physical body is NOT necessary for the experience of the bodily self. Melzack proposed “that the brain generates the experience of the body and that sensory inputs merely modulate our bodily experience.” Phantom limbs are “produced by the same brain processes that underlie the experience of the body when it is intact”

Bodily self for the entire body Are there phantom bodies and phantom selves?

Out-of-body experiences: abnormal bodily self-consciousness

Extracorporeal Self-location (or disembodiment) I am localized outside my body

Extracorporal first-person perspective I perceive the world (and my body) from a disembodied perspective

Self-identification I identify with the elevated body

[Devinsky et al., Arch Neurol 1989; Brugger, Neuropsychiatr 2002; Blanke et al., Nature 2002; Brain 2004; Ionta et al., Neuron 2011]

Neurology of out-of-body experiences Brain damage is localized in right superior temporal gyrus/angular gyrus

-OBEs are illusory own body perceptions -Brain damage centers in temporo-parietal junction -Brain damage leads to double disintegration of multisensory bodily information ( Visual-tactile-proprioceptive signals and visuo-vestibular signals)

Manipulating Self-location and Self-identification in healthy subjects

Video ergo sum

[see also video on youtube: « Virtual rubber hand illusion »]

Self-consciousness & visuo-tactile integration: The rubber hand illusion

A fake arm feels like my arm and is associated with abnormal arm localization

~The rubber hand illusion~

[Botvinick and Cohen, 1998; Armel & Ramachandran, 2003; Ehrsson et al., 2005; Tsakiris & Haggard, 2005; Evans & Blanke, NeuroImage 2012]

Questionnaire responses « I feel the touch where I see the touch » « The fake hand feels like my real hand »

Arm position recalibration

From hand to body:

Projecting the bodily self to a fake body

Subject with Head Mounted Display (covered)

Video camera with 3-D converter

2m

Virtual body

Actual body

[Lenggenhager et al., Science 2007]

Embodiment of virtual and artificial bodies A virtual or filmed body feels like my body and “I”

am localized at the virtual body’s position

anterior shift

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Laboratory of Cognitive Neuroscience

[Lenggenhager et al., 2007]

[youtube: « Virtual out-of-body experience »]

Self-identifcation Self-location

Questionnaire Position

Recalibration

Study 2 [Lenggenhager et al., 2007]

Laboratory of Cognitive Neuroscience

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These changes in self-consciousness are body specific, change touch perception, and decrease pain

[Palluel et al., J Neurophysiol, 2011; Hänsel et al., 2011]

Increase in pain thresholds

[Ehrsson, 2007; Petkova and Ehrsson, 2008]

EEG & Virtual Reality

Body condition Control condition

Synchronous/asynchronous

[Ionta et al., Neuron 2011; Duenas et al., IEEE 2012; Pfeiffer et al., POne 2013]

The brain mechanisms of bodily self-consciousness: Neuroscience robotics

Self-location

Activity in right and left posterior superior temporal gyrus reflects self-location that depends on the first-person perspective

[Ionta et al., 2011] Laboratory of Cognitive Neuroscience

Pathologically & experimentally induced changes in bodily self-consciousness converge onto bilateral (right) temporo-parietal cortex

� TPJ activity (within a network of related brain regions) reflects one of the most fundamental subjective feelings in humans: Self-location and first-person perspective

VLSM

��Functional connectivity between the right and the left TPJ with the right

insula (and right medial prefrontal cortex) reflects self-location and 1PP

Self-related fc fMRI Self location dependant fc fMRI

Bodily self-consciousness brain mechanisms extend beyond temporo-parietal cortex

[Ionta et al., submitted]

Autobiographical Memory

Thought: Cogito Ergo Sum

Visual Mirror Recognition

The Self in Cognitive Neuroscience

Bodily self-consciousness: How the brain processes signals from the body is the foundation for the self

Jeannerod, Frith, Ramachandran Damasio, Craig

Bodily self-consciousness based on exteroceptive bodily cues versus interoceptive cues Visceroception and the insula

AIC MIC PIC

[Damasio, 2000; Critchley et al., Nat Neurosci 2004; Craig, Nat Neurosci Rev 2002, 2009] Do exteroceptive (i.e. visuo-tactile) and interoceptive cues interact and affect bodily self-consciousness?

Conflict between interoceptive (heart) and exteroceptive (visual) signals: Online detection of QRS complex was used to illuminate an avatar synchronously and asynchronously with one’s own heartbeat (cardio-visual conflict)

[Aspell et al., Psychological Science 2013]

-  Cardio-visual illumination of the avatar -  a flashing silhouette around the avatar was either sync or asnyc with

respect to the participant’s heartbeat (QRS)

Turning body and self inside out: Visualized heartbeats alter self-identification and self-location

-  Body-specific and synchrony dependant changes in self identification and self-location

-  Participants were not aware of the heartbeat manipulation (middle) and this did not differ among exp. conditions

Self-identifcation Self-location

Questionnaire Position

Recalibration

Cardiac signals converge with visual & tactile signals and alter a late SEP component (insula?)

Laboratory of Cognitive Neuroscience

Synchrony dependent changes in sthe visuo-tactile crossmodal

congruency effect

P45 differs between snyc and async cardio-visual illumination

P45 amplitude correlates with

self-identification

[Heydrich, et al., submitted]

What is Self-consciousness ? Working hypothesis:

The conscious experience of being this entity (of being a person) is caused by brain activity during

spatially congruent self-identification, self-location and first-person perspective. This is based on a

bottom-up body representation based on the integration of specific somatosensory-vestibular-

visual and interoceptive signals in areas VIP, PIVC, MST, and insula.

�[Ionta et al., in revision]

[Heydrich and Blanke, Brain 2013]

1- Bodily self-consciousness as the foundation of the many-dimensional Self (and the Person)

• Visual Recognition: Recognizing one's image in a mirror • Memory: Autobiographical memory • Language: first-person pronouns, self-narrative • Social: ability to adapt the perspective of the other to oneself, • Thought: Ability to think “I” thoughts; ability to think of oneself as oneself, have a self concept, “to know that I know” • …

2- Although self-consciousness is often regarded as the greatest mystery in science (and consciousness studies), it may turn out to be less complex than we think and less complex than consciousness.

Thank you!

http://lnco.epfl.ch/ http://cnp.epfl.ch/

Center for Neuroprosthetics EPFL

Ecole Polytechnique Fédérale de Lausanne

Self-location depends on the experienced direction of the first-person perspective

Up-Lookers [Q1: Did you have the

impression to look up at the body above you or

down at the body below you?] (n=11)

Down-Lookers (n=11)

sync. stimulation leads to

opposite drift in self-location in up- and down-lookers “towards

the virtual body”)

The experienced direction of the first-person perspective can be manipulated by a visuo-vestibular conflict

Visuo-tactile-proprioceptive integration (visuo-vestibular integration)

Hand and Trunk-centered trimodal neurons in parietal and frontal cortex

[Iriki et al., Neuroreport 1996; Graziano et al., Science 2000; Duhamel et al., J Neurophysiol 1998; Blanke, Nat Rev Neurosci 2012]

Visual receptive fields Tactile receptive fields

Interoceptive out-of body experiences (Heautoscopy): Statistical lesion analysis localizes brain damage to left insula

[Heydrich and Blanke, Brain 2012]

He-autoscopy

Out-of-body experiences in normal folks

Example: «�I was asleep on a settee with my wife. I was aware at one stage that I was out of my own body poised six feet or so above and peering down at the two of us laying on the settee.�» [Green, Out-of-the-body experiences, 1968]..

“One day, at age 17, I was walking alone at night during a snowstorm in a singularly

quiet place. I noticed that the ground looked further away than usual, and then

it seems that I was looking down from a height of perhaps 10 meters, watching

myself crossing the field.” Marvin Minsky

The many selves in Cognitive Neuroscience

• Visual Recognition: Recognizing one's image in a mirror

• Memory: Autobiographical memory

• Thought: “Cogito ergo sum”, Ability to think “I” thoughts; ability to think of oneself as oneself, have a self concept

• Language: first-person and self-reflexive pronouns

• Intentions/free will

• Social: ability to adapt the perspective of the other to oneself; capacity to discriminate self from other

Self-location (Where am I localized ?)

First-person perspective

(Where do I perceive from?)

Self-identification (What do I experience as my body?)

Bodily Self-consciousness (relevance for philosophy)

[Blanke & Metzinger, TiCS 2009]