by Fabrice Sarlegna, Chris Miall, Jonathan Cole and Robert Sainburg, <a rel="nofollow noopener" target="_blank" class="article-byline__link" href="https://theconversation.com">The Conversation</a>
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<div data-thumb="https://scx1.b-cdn.net/csz/news/tmb/2021/propriocepti.jpg" data-src="https://scx2.b-cdn.net/gfx/news/2021/propriocepti.jpg" data-sub-html="Proprioception makes it possible to situate the body in space. Credit: Pixabay, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a>">
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Proprioception makes it possible to situate the body in space. Credit: Pixabay, <a rel="nofollow noopener" target="_blank" class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a>
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Vision. Hearing. Smell. Taste. Touch. Proprioception. Proprioception? Few people are familiar with this sense, although its pioneer studies in the 19th century were by some of the giants of neuroscience: Claude Bernard who had a French university named after him, Sir Charles Bell, and Sir Charles Sherrington who won the Nobel Prize in Physiology/Medicine in 1932 and who coined the term proprioception.
<p>So what is proprioception? It is the sense allowing us to feel and locate our body parts. Close your eyes, ask someone to move your right foot, and you will still know where it is. In fact, you can describe your body posture thanks to the integration by the nervous system of neurophysiological signals from receptors—proprioceptors—in the muscles, tendons, joints and skin that are sensitive to muscle length and force, to joint rotation, and to local bending of the skin. Proprioception is a key component of our "global positioning system," which is essential in our daily life because we need to know where we are in order to move somewhere. Proprioception enables us to determine each body part's position, speed and direction, whether we see it or not, and so enables the brain to guide our movements.
To understand the role of proprioception, researchers have studied rare patients who are deprived of it by disease of their peripheral nerves. Those individuals are unable to perform coordinated movements. The reason for the motor impairment is made clear when a patient, asked to move the legs by a neurologist, answers “Sure, Doc, as soon as I find them.” Oliver Sacks described such a subject in the chapter, “The disembodied lady,” in the best-seller “The Man Who Mistook His Wife for a Hat” (1985). There, Christina is a young woman who has lost proprioception. She can hardly stand and even if she observes her hands carefully, she can barely use them. Other related cases were studied by scientists: Ian Waterman’s story about his “missing body” was the basis of a 1997 BBC documentary, “The Man Who Lost His Body.” It also appeared in two of Peter Brook’s plays, “The Man Who” (1993) and “The Valley of Astonishment” (2014), as well as Jonathan Cole’s books “Pride and a Daily Marathon” (1995) and “Losing Touch: A Man without His Body” (2016).