Body Representation Flashcards
what are the requirements for representing our body?
1) pre-existing stored model of body
2) on-line representation of body at any one moment
3) anatomical structure of body leads to recalibration of visual and tactile system
4) subjective conscious experience of ownership of body
what does pre-existing stored model of body mean?
- have to have a pre-existing stored model of our body: have to have some memory of what our body is, allows us to distinguish between our body from others’ bodies
what does on-line representation of body at any one moment mean?
- have to have on-line representation of our body at one moment, on-line moment to moment representation needs to be flexible and allow us to give control to our body movements efficiently. brain needs to modulate the interaction of multisensory information from: vision, touch, proprioception, interoception.
what does anatomical structure of body leads to recalibration of visual and tactile systems mean?
- anatomical posture rep of body leads to recalibration of vis and tactile coordinates systems, need to align with spatial framework and touch and vision uses in order to kick ball.
what does subjective conscious experience of ownership of body mean?
-subjective conscious exp of body ownership, where we are and our limbs are in space, awareness takes in peripersonal states and how large they are and what factors interfere with peripersonal space around us. it’s the space that’s reachable around us and is highly plastic and extent of peripersonal space there are huge ID’s.
what is interoception?
interoception, the perception of the state of ourselves like ability to perc our heart rate or other internal cues to our state, breathing rate etc., great ID’s in our ability to perc our internal state! some are strong at this and some are poor at this!
to what extent do we perc control and ownership over our own bodies?
- body image: shape of body, type of dimensions that pertains to body image, body image can change and there are ID’s in the way that we perc image of our own bodies.
- interoceptive cues like whether we feel hungry contribute to perc of bodily self.
- action system can have knock on effect on our moment to moment rep of our bodily self, schema of our body: how big are our hands and knowledge of this helps us interact with objects. agency is sense of voluntary and involuntary actions on the world, all aspects feed into a global rep of ourselves.
actions would not work well on static reps of ourselves is what researchers are interested in.
what are examples of psychiatric disorders associated with inefficient rep of one’s own body?
- Cotard syndrome is the illusion that they are dead and don’t exist, no sense of internal self, one has lost their blood and internal organs.
- Interoceptive agnosia is the loss of sense of pain.
- Mirror sign is the inability to recognise one’s own image in the mirror.
- Misoplegia is hatred towards one’s own body parts.
- Somatoparaphrenia/ Alien Head is the denial of ownership of one’s body part.
- Body integrity identity disorder (BIID) is the urge to be amputated of one’s own perfectly healthy limbs.
- Heautoscopy is visual hallucination of a double of oneself at a distance.
…range from benign to the rare, but v curious disorders.
what are the neural substrates involved with body representation?
- EBA/ extra-striate body area in visual cortex.somatosensory cortex maps out body into what we call homunculus, role of vision is to represent one’s own body in homunculus, what we see can affect what we tactically feel and affect the rep of body is homunculus.
- Proprioception is the perception of limb position in space and on body.
- Perception-for-action: the role of the parietal cortex in body representation
Downing, Jiang, Shuman and Kanwisher, 2001? discovery of EBA
visual area involved in rep own body is the EBA/extra-striate body area.
noticed there is a region of visual cortex that responds only to shapes of bodies, strong activation in right occipitotemporal cortex (EBS) to bodies and body parts more so than objects and object parts.
Downing et al, 2001?
category-specific activation to human bodies..like the silhouette of a body, isolated body parts etc.
Astafiev, Stanley, Shulman and Corbetta, 2004: does EBA respond to v specific representations of bodies i.e. static representation, or does it respond to bodies that actually move?
EBA was sensitive to changes in body motion, activated to goal-directed movement in participants.
- doesn’t matter which body part was about to move towards target area, the intention to move caused greater activation in EBA area. - depicts the shape of a body in ventral region of vis cortex (cortical stream, ie. ventral stream goes to temporal cortex…object recognition, so this is body (object) recognition) so we know its related to shape.. also responds to movements that are goal directed.
Peelen and Dowling, 2005?
they argued that it’s not the EBA that is responding to movements and that it just represents anatomical shape. argued a region slightly adjacent to the EBA called the Action Related Region. debate continued between two groups about whether EBA incorporated motion or not.
Striem-Amit and Amedi, 2014: whether EBA is acc a visual area or not?
diff sensory systems can modulate activation in regions of the visual cortex, can EBA be activated by other inputs?
- trained blind for 70hrs using vOICe technology, system that converts visual images into a soundscape.
- Used fMRI to measure brain responses to soundscapes of body-shape silhouettes, objects faces and abstract patterns.
- EBA was activated in both groups, region that codes for shape of bodies but doesn’t have to be visually presented shape, can be shapes that are applied through other sensory systems.
- Both blind and sighted groups showed larger responses to body-shape silhouettes than to other images in the EBA… why would blind have part of brain that would represent body shapes if they’d never make use of it?
…findings were interpreted as evidence that the specialisation found in the visual cortex may exist independently of experience.
Constantini, 2011: somatosensory system has rep of body, does EBA receive input from tactile system about our body shape?
EBA is activated through haptic exploration of body parts.
- doesn’t activate to objects similar in scale or texture but body parts do…blind may have region in vis system dedicated to anatomical representation of bodies through tactile system!
