Scientists from Manchester University (Murray and his team [1][2]) have proven that patients suffering pain in their inexsistent phanton limbs can relieve pain by using visualisation. Using different techniques, from a simple mirror to advanced virtual reality systems where the patient is able to even control the virtual limb, researchers have proven that visualisation can help the brain to relieve the 'phantom' pain.

Somehow, the brain recalls sensory information coming from the amputated limb, and this causes conscious pain in the patient. These results suggest that self-consciousness mechanisms are affected by the amputation and the brain cannot automatically adapt its internal model.

[1] C. D. Murray, E. Patchick, S. Pettifer, T. Howard, J. Kalkarni, and C. Bamford. Investigating the efficacy of a virtual mirror box in treating phantom limb pain in a sample of chronic sufferers. International Journal of Disability and Human Development, page to appear, 2007.

[2] C. D. Murray, S. Pettifer, T. Howard, E. Patchick, J. Kalkarni, and C. Bamford. The treatment of phantom limb pain using immersive virtual reality: three case studies. Disability and Rehabilitation, page to appear, 2007.

Related Links:

• Dr. Steve Pettifer page.
• Dr. Craig Murray Page.

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As published in the last issue of JAMA (The Journal of the American Medical Association) by Irene Tracey (Oxford University) emotions and motivations play an important role in the mechanisms of the perception of pain in the human brain. Using brain imaging techniques with patients suffering chronic pain neuroscientists have discovered that pain perception areas are activated at the same time as expectation areas. In one hand, anxiety and anticipation can worsen a pain experience. On the other hand, positive experiences can relieve the pain perception.

Cognition and consciousness mechanisms obviously greatly affect the amount of perceived pain. As Tracey argues, pain requires much attention. She has demonstrated that inattentive or amused subjects feel less discomfort when applying heat in the hand. In fact, distraction techniques are being evaluated as painkillers.

Other conscious pain inhibitors are motivations. When a harmful stimulus appears, the perception of the pain can be reduced if there is a reason to ignore the pain. For instance, during the search for food, endogenous opioids are released to eliminate the pain feeling, Tracey explains in her paper.

• Link to University of Oxford PAIN Group. 
  

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The most popular theory that tries to account for the extremely fast evolution of human brain is the "Machiavellian intelligence" hypothesis (also known as "social brain" hypothesis).

Human brain has evolved much faster than other mammals. In only 25 million years lots of mutations have taken place in many human genes. The Machiavellian intelligence hypothesis might explain this phenomenon, and could give us the reason why we have such a big and complex brain. According to this theory, the intense social competition was (and still is) the main reason why the human brain evolved to a highly complex organ consuming 20% of our energy. Natural selection supported those individuals whose social strategies provided them with social and reproductive success. Sophisticated “Machiavellian” strategies, involving social behaviors like lying, cunning or leadership were the means to be successful in the emerging complex society.

Sergey Gavrilets and Aaron Vose, from the University of Tenesse, have provided data that supports this hypothesis. They have designed a mathematical model to simulate the development of human brain according to the Machiavellian intelligence theory. In their model, the genes control brains that invent and learn social strategies (memes). These strategies are used by males in their competition for mates. The model suggests that cerebral capacity evolves faster that learning capacity, and the advantage of having a large brain decreases as the exposure to memes increase in modern societies.

Source: The dynamics of Machiavellian intelligence . Proc. Natl. Acad. Sci. USA, 10.1073/pnas.0601428103. Abstract.

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As reported last week in Science, a team of researchers in Cambridge have demonstrated that a patient in vegetative state preserved conscious awareness. Using a fMRI scanner the patient showed same activation patterns as healthy volunteers when she was asked to imagine playing tennis. Dr. Adrian Owen, the leader of this research, claim that the vegetative diagnosed brain was able to understand the meaning of sentences and respond consciously. For a detailed description of the research visit the Medical Research Council website. This specific research work is published in Science, 8th September 2006 under the title Detecting Awareness in the Vegetative State.

If these research conclusions are confirmed, it means that current techniques to assess the level of consciousness of humans are not fully valid. One might be unable to move or speak, however that does not neccesarily means that the subject is unable to experience some level of consciousness.

Taking this idea about consciousness level assesment to the field of machine consciousness, one could think about the best way to determine the level of awareness of a robot. Obviously, the first reference is always the Turing test. However, as demonstrated in humans, a purely external evaluation could not be valid in terms of assessing the real level of consciousness of an artificial entity. Anyway, from a strictly engineering point of view this question is irrelevant.

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Pinky and the Brain. The Brainstem.

Here we have a scientific description of the main parts of human brain by Pinky. The funniest way to learn about human brain. Enjoy it! 

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