Interesting!
Out of Body Experience
by Sandra Blakesler (Gulf News, October 13, 2006)
Delivering mild electric current to specific spots in the brain can induce it, neuroscientists suggest. A recent study conducted by Dr. Olaf Blanke provides new scientific insight into experiences more often left to paranormal explanations. Stimulating a part of the brain called the angular gyrus on opposing sides yielded two distinct results. Stimulation of the left angular gyrus gave the patient a sensation of a shadow person lurking behind. Stimulation of the right angular gyrus resulted in an out-of-body experience, as if the patient were floating from the ceiling, looking down at herself.
They are eerie sensations, more common than one might think: A man describes feeling a shadowy figure standing behind him, then turning around to find no one there. A woman feels herself leaving her body and floating in space, looking down on her corporeal self. Such experiences are often attributed by those who have them to paranormal forces. But according to recent work by neuroscientists, delivering mild electric current to specific spots in the brain can induce them. In one woman, for example, a zap to a brain region called the angular gyrus resulted in a sensation that she was hanging from the ceiling, looking down at her body. In another woman, electrical current delivered to the angular gyrus produced an uncanny feeling that someone was behind her, intent on interfering with her actions.
The two women were being evaluated for epilepsy surgery at University Hospital in Geneva, where doctors implanted dozens of electrodes into their brains to pinpoint the abnormal tissue causing the seizures and to identify adjacent areas involved in language, hearing or other essential functions that should be avoided in the surgery. As each electrode was activated, stimulating a different patch of brain tissue, the patient was asked to say what she was experiencing.
Dr Olaf Blanke, a neurologist at the Ecole Polytechnique Federale de Lausanne in Switzerland who carried out the procedures, said that the women had normal psychiatric histories and that they were stunned by the bizarre nature of their experiences. The September 21 issue of Nature magazine includes an account by Blanke and his colleagues of the woman who sensed a shadow person behind her. They described the out-of-body experiences in the February 2004 issue of the journal Brain.
Phantom Limbs
There is nothing mystical about these ghostly experiences, said Peter Brugger, a neuroscientist at University Hospital in Zurich, who was not involved in the experiments, but is an expert on phantom limbs, the sensation of still feeling a limb that has been amputated, and other mind-bending phenomena. The research shows that the self can be detached from the body and can live a phantom existence on its own, as in an out-of-body experience, or it can be felt outside of personal space, as in a sense of a presence, Brugger said.
Scientists have gained new understanding of these odd bodily sensations as they have learned more about how the brain works, Blanke said. For example, researchers have discovered that some areas of the brain combine information from several senses. Vision, hearing and touch are initially processed in the primary sensory regions. But then they flow together, like tributaries into a river, to create the wholeness of a persons perceptions. A dog is visually recognized far more quickly if it is simultaneously accompanied by the sound of its bark.
These multisensory processing regions also build up perceptions of the body as it moves through the world, Blanke said. Sensors in the skin provide information about pressure, pain, heat, cold and similar sensations. Sensors in the joints, tendons and bones tell the brain where the body is positioned in space. Sensors in the ears track the sense of balance. And sensors in the internal organs provide a readout of a persons emotional state.
Real-time information from the body, the space around the body and the subjective feelings from the body are also represented in multisensory regions, Blanke said. And if an electric current directly simulates these regions, the integrity of the sense of body can be altered. As an example, Blanke described the case of a 22-year-old student who had electrodes implanted into the left side of her brain in 2004. We were checking language areas, Blanke said, when the woman turned her head to the right. That made no sense, he said, because the electrode was nowhere near the area involved in the control of movement. Instead, the current was stimulating a multisensory area called the angular gyrus.
Blanke applied the current again. Again, the woman turned her head to the right. Why are you doing this? he asked.
The woman replied that she had a weird sensation that another person was lying beneath her on the bed. The figure, she said, felt like a shadow that did not speak or move. Because the presence closely mimicked the patients body posture and position, Blanke concluded that the patient was experienceing an unusual perception of her own body, as a double. But for reasons that scientists have not been able to explain, he said, she did not recognise that it was her own body she was sensing. The feeling of a shadowy presence can occur without electrical stimulation to the brain, Brugger said.
Six years ago, another of Blankes patients underwent brain stimulation to a different multisensory area, the angular gyrus, which blends vision with the body sense. The patient eperienced a complete out-of-body experience. When the current flowed, she said: I am at the ceiling. I am looking down at my legs. When the current ceased, she said: Im back at on the table now. What happened?
Further applications of the current returned the woman on the ceiling, causing her to feel as if she were outside of her body, floating, her legs dangling below her. When she closed her eyes, she had the sensation of doing sit-ups, with her upper body approaching her legs. Because the womans felt position in space and her actual position in space did not match, her mind cast about for the best way to turn her confusion into a coherent experience, Blanke said.
Some schizophrenics, Blanke said, experience paranoid delusions and the sense that someone is following them. They also sometimes confuse their own actions with the actions of other people. While the cause of these symptoms is not known, he said, multisensory processing areas may be involved. When otherwise normal people experience bodily delusions, Blanke said, they are often flummoxed. The felt sensation of the body is so seamless, so familiar, that people do not realise it is a creation of the brain, even when something goes wrong and the brain is perturbed.
Out of Body Experience
by Sandra Blakesler (Gulf News, October 13, 2006)
Delivering mild electric current to specific spots in the brain can induce it, neuroscientists suggest. A recent study conducted by Dr. Olaf Blanke provides new scientific insight into experiences more often left to paranormal explanations. Stimulating a part of the brain called the angular gyrus on opposing sides yielded two distinct results. Stimulation of the left angular gyrus gave the patient a sensation of a shadow person lurking behind. Stimulation of the right angular gyrus resulted in an out-of-body experience, as if the patient were floating from the ceiling, looking down at herself.
They are eerie sensations, more common than one might think: A man describes feeling a shadowy figure standing behind him, then turning around to find no one there. A woman feels herself leaving her body and floating in space, looking down on her corporeal self. Such experiences are often attributed by those who have them to paranormal forces. But according to recent work by neuroscientists, delivering mild electric current to specific spots in the brain can induce them. In one woman, for example, a zap to a brain region called the angular gyrus resulted in a sensation that she was hanging from the ceiling, looking down at her body. In another woman, electrical current delivered to the angular gyrus produced an uncanny feeling that someone was behind her, intent on interfering with her actions.
The two women were being evaluated for epilepsy surgery at University Hospital in Geneva, where doctors implanted dozens of electrodes into their brains to pinpoint the abnormal tissue causing the seizures and to identify adjacent areas involved in language, hearing or other essential functions that should be avoided in the surgery. As each electrode was activated, stimulating a different patch of brain tissue, the patient was asked to say what she was experiencing.
Dr Olaf Blanke, a neurologist at the Ecole Polytechnique Federale de Lausanne in Switzerland who carried out the procedures, said that the women had normal psychiatric histories and that they were stunned by the bizarre nature of their experiences. The September 21 issue of Nature magazine includes an account by Blanke and his colleagues of the woman who sensed a shadow person behind her. They described the out-of-body experiences in the February 2004 issue of the journal Brain.
Phantom Limbs
There is nothing mystical about these ghostly experiences, said Peter Brugger, a neuroscientist at University Hospital in Zurich, who was not involved in the experiments, but is an expert on phantom limbs, the sensation of still feeling a limb that has been amputated, and other mind-bending phenomena. The research shows that the self can be detached from the body and can live a phantom existence on its own, as in an out-of-body experience, or it can be felt outside of personal space, as in a sense of a presence, Brugger said.
Scientists have gained new understanding of these odd bodily sensations as they have learned more about how the brain works, Blanke said. For example, researchers have discovered that some areas of the brain combine information from several senses. Vision, hearing and touch are initially processed in the primary sensory regions. But then they flow together, like tributaries into a river, to create the wholeness of a persons perceptions. A dog is visually recognized far more quickly if it is simultaneously accompanied by the sound of its bark.
These multisensory processing regions also build up perceptions of the body as it moves through the world, Blanke said. Sensors in the skin provide information about pressure, pain, heat, cold and similar sensations. Sensors in the joints, tendons and bones tell the brain where the body is positioned in space. Sensors in the ears track the sense of balance. And sensors in the internal organs provide a readout of a persons emotional state.
Real-time information from the body, the space around the body and the subjective feelings from the body are also represented in multisensory regions, Blanke said. And if an electric current directly simulates these regions, the integrity of the sense of body can be altered. As an example, Blanke described the case of a 22-year-old student who had electrodes implanted into the left side of her brain in 2004. We were checking language areas, Blanke said, when the woman turned her head to the right. That made no sense, he said, because the electrode was nowhere near the area involved in the control of movement. Instead, the current was stimulating a multisensory area called the angular gyrus.
Blanke applied the current again. Again, the woman turned her head to the right. Why are you doing this? he asked.
The woman replied that she had a weird sensation that another person was lying beneath her on the bed. The figure, she said, felt like a shadow that did not speak or move. Because the presence closely mimicked the patients body posture and position, Blanke concluded that the patient was experienceing an unusual perception of her own body, as a double. But for reasons that scientists have not been able to explain, he said, she did not recognise that it was her own body she was sensing. The feeling of a shadowy presence can occur without electrical stimulation to the brain, Brugger said.
Six years ago, another of Blankes patients underwent brain stimulation to a different multisensory area, the angular gyrus, which blends vision with the body sense. The patient eperienced a complete out-of-body experience. When the current flowed, she said: I am at the ceiling. I am looking down at my legs. When the current ceased, she said: Im back at on the table now. What happened?
Further applications of the current returned the woman on the ceiling, causing her to feel as if she were outside of her body, floating, her legs dangling below her. When she closed her eyes, she had the sensation of doing sit-ups, with her upper body approaching her legs. Because the womans felt position in space and her actual position in space did not match, her mind cast about for the best way to turn her confusion into a coherent experience, Blanke said.
Some schizophrenics, Blanke said, experience paranoid delusions and the sense that someone is following them. They also sometimes confuse their own actions with the actions of other people. While the cause of these symptoms is not known, he said, multisensory processing areas may be involved. When otherwise normal people experience bodily delusions, Blanke said, they are often flummoxed. The felt sensation of the body is so seamless, so familiar, that people do not realise it is a creation of the brain, even when something goes wrong and the brain is perturbed.
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