BODY REPRESENTATION

TOOLS FOR EXPLORING THE BODY IMAGE AND BODY SCHEMA

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Luca Rinaldi

LESSON 9

LAB: COGNITIVE AND BEHAVIORAL MEASURES

MY BODY?

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Which is my body and how do I distinguish it from the bodies of others, or from

objects in the surrounding environment?

The perception of our own body and more particularly our sense of body ownership

is taken for granted.

IS THAT MY BODY

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Which is my body and how do I distinguish it from the bodies of others, or from

objects in the surrounding environment?

The perception of our own body and more particularly our sense of body ownership

is taken for granted.

Findings from body ownership illusions, show that under specific multisensory

conditions, we can experience artificial body parts or fake bodies as our own

DIFFERENT BODY REPRESENTATIONS

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- Explicit Representation

- Canonical posture

- Based on visual input

BODY IMAGE BODY SCHEMA

- Implicit Representation

- Proprioception

- Action-oriented

Head & Holmes, 1911

Patients could not touch one’s

own body parts, if touched by

the experimenter

Patients could not touch one’s

own body parts in vision, but

could do that once it was

touched by the experimenter

without it

SCHIZOPHRENIA

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Altered body consciousness in schizophrenic and hallucinated patients

Daprati et al., 1997

SOMATOPARAPHRENIA

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A sense of disownership: the delusional belief that the contralesional limbs do not

belong to one's own body but to another person

Romano et al., 2014

BODY ILLUSION

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Body illusion distorsion: in which people can perceive that the size or the posture of

their body part(s) have changed dramatically

Body illusion ownership: refer to the illusory perception of non-bodily objects (e.g.,

artificial limbs) as being parts of one’s own body

BODY ILLUSION DISTORSION

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People can perceive that the size or the posture of their body part(s) have changed

dramatically without necessarily satisfying the anatomical constraints of the human

body

Illusory body distortions relies on kinaesthetic illusions, in which blindfolded

subjects experience the illusory movement of a static body part and therefore non-

veridical proprioceptive states

THE PINOCCHIO ILLUSION

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A blindfolded participant receives vibration on his biceps while touching the tip of his

nose with his fingers. The illusory extension of the arm generates the illusion that his

nose, his fingers or both are elongating (Lackner, 1988)

THE PHANTOM NOSE ILLUSION

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The experimenter moves the finger of a blindfolded participant to tap the nose of

another subject, while simultaneously tapping the nose of the participant (Ramachandran and Hirstein, 1998)

Conflicting visual-somatosensory input in virtual reality to disrupt the spatial

unity between the self and the body

FULL BODY ILLUSION

11Lenggenhager et al., 2007

FULL BODY ILLUSION

12Lenggenhager et al., 2007

Conflicting visual-somatosensory input in virtual reality to disrupt the spatial

unity between the self and the body

BODY ILLUSION OWNERSHIP

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Illusory perception of non-bodily objects (e.g., artificial limbs) as being parts of one’s

own body and as being the source of the associated bodily sensations, such as

touch

One can get to experience a mannequin’s hand as his/her own hand, and have strong

physiological responses when seeing it being attacked with a knife

THE RUBBER HAND ILLUSION

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Healthy adults experience a rubber hand as if it were their own hand (Botvinick & Cohen,

1998)

THE RUBBER HAND ILLUSION

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Healthy adults experience a rubber hand as if it were their own hand (Botvinick & Cohen,

1998)

Experienced when touch between the real and rubber hand is synchronous

THE RUBBER HAND ILLUSION

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Healthy adults experience a rubber hand as if it were their own hand (Botvinick & Cohen,

1998)

Experienced when touch between the real and rubber hand is synchronous

Questionnaire

THE RUBBER HAND ILLUSION

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Healthy adults experience a rubber hand as if it were their own hand (Botvinick & Cohen,

1998)

Experienced when touch between the real and rubber hand is synchronous

Proprioceptive drift

Not all objects can be experienced as part of one’s body!

AN INDEX OF EMBODIMENT?

18Tsakiris et al., 2009

Outgroup racial cues interfere with the process of embodiment of the rubber

hand hand

AN INDEX OF EMBODIMENT?

19Lira et al., 2017

THE MIRROR BOX THERAPY

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The Mirror box (MB) therapy was originally developed by Ramachandran as a tool

to reduce phantom limb pain after amputation (Ramachandran & Rogers-Ramachandran,

1996)

THE MIRROR BOX THERAPY

21Foell et al., 2013

The MB therapy induces a reduction of phantom limb sensation

THE MIRROR BOX THERAPY

22Romano et al., 2013

The MB in normal participants

THE MIRROR BOX THERAPY

23Romano et al., 2013

Proprioceptive sensory uncertainty in the hand inside the box

BODY DIMENSION

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The representation of body size

HAND REPRESENTATION

25Longo et al., 2008

HAND REPRESENTATION

26Longo et al., 2008

BODY SIZE AND PAIN

27Mancini et al., 2011

Simply viewing the body reduces the reported intensity of acute physical pain

(analgesia)

BODY SIZE AND PAIN

28Mancini et al., 2011

Visual enlargement of the viewed hand enhanced analgesia, whereas visual

reduction of the hand decreased analgesia

DECODING TACTILE ORDER

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TEMPORAL ORDER OF TOUCH

30Yamamoto & Kitazawa, 2001

Simply report which hand was simulated first (i.e., different intervals between

the two vibrotactile stimulations)

TEMPORAL ORDER OF TOUCH

31Yamamoto & Kitazawa, 2001

Disruption of temporal perception with crossed hands

TEMPORAL ORDER OF TOUCH

32Roder et al., 2004

Is this driven by a conflict between external and bodily-centered coordinates

due to vision?

TEMPORAL ORDER OF TOUCH

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The performance of late, but not of congenitally, blind people was impaired by

crossing the hands

Roder et al., 2004

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SEE YOU NEXT LESSON!