People can be easily tricked into believing an artificial finger is their own, shows a study published today in The Journal of Physiology. The results reveal that the brain does not require multiple signals to build a picture body ownership, as this is the first time the illusion has been created using sensory inputs from the muscle alone.
The discovery provides new insight into clinical conditions where body representation in the brain is disrupted due to changes in the central or peripheral nervous systems e.g. stroke, schizophrenia and phantom limb syndrome following amputation.
Professor Simon Gandevia, Deputy Director of Neuroscience Research Australia (NeuRA), says: "It may seem silly to ask yourself whether your index finger is part of your body. However, our current findings demonstrate that this question has led to important insights into key brain functions.
"These findings could lead to new clinical interventions where the addition or the removal of specific sensory stimuli is used to change someone's body image."
In the experiment, subjects held an artificial finger with their left hand that was located 12 cm above their right index finger. Vision was eliminated and anaesthesia was used to numb the skin and remove feelings of joint movement. When the artificial finger and the right index finger were moved synchronously, subjects reported they were holding their own index finger: the brain incorrectly incorporated the artificial finger into its internal body representation.
The human brain uses sensory signals to maintain and update internal representation of the body, to plan and generate movements and interact with the world. The study gives new understanding as to how the brain decides what is part of our own body and where it is located. Contrary to previous theories which used multiple sensory inputs including touch and vision, these results demonstrate that messages coming from muscle receptors are enough to change the internal body representation.
The team additionally found a new type of sensory 'grasp illusion' in which perceived distances between index fingers decreases when subjects hold an artificial finger. This implies that the brain generates possible scenarios and tests them against available sensory information.
Professor Gandevia says: "Grasping the artificial finger induces a sensation in some subjects that their hands are level with one another, despite being 12 cm apart. This illusion demonstrates that our brain is a thoughtful (yet at times gullible!) decision maker: it uses available sensory information and memories of past experiences to decide what scenario is most likely (i.e. 'my hands are level')."
Explore further: Heartbeats link mind and body together
More information: Héroux M, Walsh L, Butler A and Gandevia S (2013). Is this my finger? Proprioceptive illusions of body ownership and representation. The Journal of Physiology. DOI: 10.1113/jphysiol.2013.261461
Medical Xpress on facebook
Related Stories
Heartbeats link mind and body together
Aug 15, 2013
While we're not necessarily aware of our heartbeat, this inner rhythm actually contributes to how we experience the body, and what belongs to it, according to research recently conducted at EPFL. A study to be published in ...
Body representation differs in children and adults, study finds
Apr 04, 2013
(Medical Xpress)—Children's sense of having and owning a body differs from that of adults, indicating that our sense of physical self develops over time, according to a new study published in Psychological Science, a jour ...
Acute pain is eased with the touch of a hand
Sep 23, 2010
There may be a very good reason that people naturally clutch their hand after receiving an injury. A new report published online on September 23 in Current Biology shows that self-touch offers significant relief for acute ...
Phantom limb formation relates to how sensory contact is lost
Dec 05, 2011
The phantom limbs perceived by many amputees and others who lose sensory connection with their bodies, do not form in “default” postures as often thought, but instead coalesce into positions that ...
Sense of smell: The nose and the brain make quite a team... in disconnection
Aug 12, 2013
Alan Carleton's team from the Neuroscience Department at the University of Geneva (UNIGE) Faculty of Medicine has just shown that the representation of an odor evolves after the first breath, and that an olfactory retentivity ...
Recommended for you
First evidence that fear memories can be reduced during sleep
5 hours ago
A fear memory was reduced in people by exposing them to the memory over and over again while they slept. It's the first time that emotional memory has been manipulated in humans during sleep, report Northwestern ...
Covert operations: Your brain digitally remastered for clarity of thought
Sep 20, 2013
The sweep of a needle across the grooves of a worn vinyl record carries distinct sounds: hisses, scratches, even the echo of skips. For many years, though, those yearning to hear Frank Sinatra sing "Fly Me ...
Building the best brain: Researchers show how brain cell connections get cemented early in life
Sep 20, 2013
When we're born, our brains aren't very organized. Every brain cell talks to lots of other nearby cells, sending and receiving signals across connections called synapses.
New insights into control of neuronal circuitry could lead to treatments for an inherited motor disorder
Sep 20, 2013
The cerebellum is a region of the brain critical for balance, learning of motor skills and coordination of movements. In the outer layer of the cerebellum, individual 'Purkinje' cells integrate inputs from ...
Neuronal activity in the visual cortex controlled by both where the eyes are looking and what they see
Sep 20, 2013
Even though our eyes are constantly moving, the brain perceives the external world as stationary—a feat achieved by integrating images acquired by the retina with information about the direction of the ...
Competing impairment of neurons governs pathology of a severe form of epilepsy
Sep 20, 2013
Dravet syndrome is a rare and severe form of epilepsy caused primarily by inherited loss-of-function mutations in a gene called SCN1A. This gene encodes a sodium ion channel known as Nav1.1 and is required ...
User comments
© Medical Xpress 2011-2013, Phys.org network
People can be easily tricked into believing an artificial finger is their own, shows a study published today in The Journal of Physiology. The results reveal that the brain does not require multiple signals to build a picture body ownership, as this is the first time the illusion has been created using sensory inputs from the muscle alone.
The discovery provides new insight into clinical conditions where body representation in the brain is disrupted due to changes in the central or peripheral nervous systems e.g. stroke, schizophrenia and phantom limb syndrome following amputation.
Professor Simon Gandevia, Deputy Director of Neuroscience Research Australia (NeuRA), says: "It may seem silly to ask yourself whether your index finger is part of your body. However, our current findings demonstrate that this question has led to important insights into key brain functions.
"These findings could lead to new clinical interventions where the addition or the removal of specific sensory stimuli is used to change someone's body image."
In the experiment, subjects held an artificial finger with their left hand that was located 12 cm above their right index finger. Vision was eliminated and anaesthesia was used to numb the skin and remove feelings of joint movement. When the artificial finger and the right index finger were moved synchronously, subjects reported they were holding their own index finger: the brain incorrectly incorporated the artificial finger into its internal body representation.
The human brain uses sensory signals to maintain and update internal representation of the body, to plan and generate movements and interact with the world. The study gives new understanding as to how the brain decides what is part of our own body and where it is located. Contrary to previous theories which used multiple sensory inputs including touch and vision, these results demonstrate that messages coming from muscle receptors are enough to change the internal body representation.
The team additionally found a new type of sensory 'grasp illusion' in which perceived distances between index fingers decreases when subjects hold an artificial finger. This implies that the brain generates possible scenarios and tests them against available sensory information.
Professor Gandevia says: "Grasping the artificial finger induces a sensation in some subjects that their hands are level with one another, despite being 12 cm apart. This illusion demonstrates that our brain is a thoughtful (yet at times gullible!) decision maker: it uses available sensory information and memories of past experiences to decide what scenario is most likely (i.e. 'my hands are level')."
Explore further: Heartbeats link mind and body together
More information: Héroux M, Walsh L, Butler A and Gandevia S (2013). Is this my finger? Proprioceptive illusions of body ownership and representation. The Journal of Physiology. DOI: 10.1113/jphysiol.2013.261461
Medical Xpress on facebook
Related Stories
Heartbeats link mind and body together
Aug 15, 2013
While we're not necessarily aware of our heartbeat, this inner rhythm actually contributes to how we experience the body, and what belongs to it, according to research recently conducted at EPFL. A study to be published in ...
Body representation differs in children and adults, study finds
Apr 04, 2013
(Medical Xpress)—Children's sense of having and owning a body differs from that of adults, indicating that our sense of physical self develops over time, according to a new study published in Psychological Science, a jour ...
Acute pain is eased with the touch of a hand
Sep 23, 2010
There may be a very good reason that people naturally clutch their hand after receiving an injury. A new report published online on September 23 in Current Biology shows that self-touch offers significant relief for acute ...
Phantom limb formation relates to how sensory contact is lost
Dec 05, 2011
The phantom limbs perceived by many amputees and others who lose sensory connection with their bodies, do not form in “default” postures as often thought, but instead coalesce into positions that ...
Sense of smell: The nose and the brain make quite a team... in disconnection
Aug 12, 2013
Alan Carleton's team from the Neuroscience Department at the University of Geneva (UNIGE) Faculty of Medicine has just shown that the representation of an odor evolves after the first breath, and that an olfactory retentivity ...
Recommended for you
First evidence that fear memories can be reduced during sleep
5 hours ago
A fear memory was reduced in people by exposing them to the memory over and over again while they slept. It's the first time that emotional memory has been manipulated in humans during sleep, report Northwestern ...
Covert operations: Your brain digitally remastered for clarity of thought
Sep 20, 2013
The sweep of a needle across the grooves of a worn vinyl record carries distinct sounds: hisses, scratches, even the echo of skips. For many years, though, those yearning to hear Frank Sinatra sing "Fly Me ...
Building the best brain: Researchers show how brain cell connections get cemented early in life
Sep 20, 2013
When we're born, our brains aren't very organized. Every brain cell talks to lots of other nearby cells, sending and receiving signals across connections called synapses.
New insights into control of neuronal circuitry could lead to treatments for an inherited motor disorder
Sep 20, 2013
The cerebellum is a region of the brain critical for balance, learning of motor skills and coordination of movements. In the outer layer of the cerebellum, individual 'Purkinje' cells integrate inputs from ...
Neuronal activity in the visual cortex controlled by both where the eyes are looking and what they see
Sep 20, 2013
Even though our eyes are constantly moving, the brain perceives the external world as stationary—a feat achieved by integrating images acquired by the retina with information about the direction of the ...
Competing impairment of neurons governs pathology of a severe form of epilepsy
Sep 20, 2013
Dravet syndrome is a rare and severe form of epilepsy caused primarily by inherited loss-of-function mutations in a gene called SCN1A. This gene encodes a sodium ion channel known as Nav1.1 and is required ...
User comments
© Medical Xpress 2011-2013, Phys.org network
0 comments:
Post a Comment