Petkova Ehrsson Body Self Perception Image

Jul 09, 2011 01:32 PM  Dynamite article... free and on-line

title =  Body self-perception

from page 50..

Body self-perception  by Valeria Petkova and Henrik Ehrsson

how we feel ownership of our limbs and our entire bodies,  

why we experience that we are "inside" our physical body,

and how the brain distinguishes btwn sensory signals

 from objects in the external world and from parts of the body.

impt applications... eg in building prosthetic limbs and simulated bodies in VR that feel just like real bodies.

Investigators of mechanisms and processes.

page 51

how we recog own bodies is SIGNIF first step for understanding SELF-AWARENESS more generally.

somatoparaphrenia... part of your body belongs to someone else!!!

asomatognosia  (what I used to call somatotopagnosia)  deficit in body awareness. 

  denying, disowning a body part).

last page...projection of ownership onto simulated bodies.

Wm James.... the body is always there!!!

rubber hand illusion... is it real  ... 2 objective tests:

1)  point to the location of your real hand  and 2)  SCR  = GSR  skin conductance response.

OUT-OF-BODY illusion...

VR study...   Illusory body  with head-mounted display.

fig 1 and fig 2;   NEW ARTIFICIAL  (rubber) BODY !!!

where one is located in space... determined by the 

visual first-person perpective in combo with

correlated visual and tactile signals in body-centered reference frames.

page 52   (look at list of 4 properties below.... crucial!!)

BODY-SWAPPING  ILLUSION... figure 2  !!!

1)  to body swap... the object has to look sufficiently similar to a human body.

2)  visual, tactile, proprioceptive signals must be temporally and spatially correlated

in coordinate systems centered on the body.

3)  when executing voluntary movements, the sensory feedback must MATCH

the expected sensory feedback from the intended movements.

4)  The visual info from the FIRST-PERSON perspective

plays an important role in establishing the location of the

perceived body relative to environmental landmarks  and in defining the

ORIGIN of the body-centered reference frame.

The perception of one's body is thus CONTINUOUSLY CONSTRUCTED

on the basis of the available sensory evidence guided by these principles,

demonstrating a remarkable DYNAMIC NATURE of the BODY REPRESENTATION.  jkjkj

page 52  BRAIN AND NEURAL INVOLVEMENT

neuronal substrates of body self-perception involve multisensory areas in the

frontal and parietal lobes that receive

convergent visual, tactile, and proprioceptive afferent inputs .

VENTRAL PREMOTOR CORTEX  and areas in the

INTRAPARIETAL CORTEX that integrate multisensory info in limb-centered reference frames

from the space near the body. ...

page 53

Likely that ownership of entire bodies involves similar multisensory mechanisms

perhaps with the addition of spatial processing in the

RIGHT INFERIOR PARIETAL CORTEX related to the ID of

WHERE THE BODY IS LOCATED in the environment.  (!!!)s

this is a MAJOR ADVANCE in study of body awareness and self-consciousness!!!

new clinical and industrial applications:  eg  enhance the feeling of ownership of artificial limbs used by amputees.

and project ownership onto simulated bodies...  enhance realism and feeling of PRESENCE.

Petkova Ehrsson Body Self Perception Image

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