Making Sense of Proprioception
I can touch my nose with my eyes closed. Can you? You might be thinking what an odd question that was. I mean, forget such a simple action. Our bodies can do more complicated things.
Navigating the car through the traffic while singing along to the radio.
Texting on the phone under the desk while pretending to listen to a lecture.
Stumbling to the washroom in the middle of the night.
Balancing in the Chaturanga pose.
Juggling all the grocery bags while walking up the numerous flights of stairs.
We can do all this and more. But have you ever thought about what makes these actions possible?
What is more important for us, at an elemental level, than the control, the owning and operation, of our own physical selves? And yet it is so automatic, so familiar, we never give it a thought.― Oliver Sacks, The Man Who Mistook His Wife for a Hat
Sacks is right. I don’t think we have given it a thought on what helps us move in the world. At least I haven’t. But having come across this concept in the book, The Man Who Mistook His Wife for a Hat, I was enlightened and was curious to know more.
Proprioception
Proprioception is the sense positioning and movement of different body parts relative to our environment. It is sometimes called the sixth sense (after sight, smell, taste, touch, and hearing) and this is what helps us perform our day to day activities as simple as walking in a straight line.
What happens in our body that facilitates this remarkable ability?
The anatomy that aids proprioception
Proprioception is a constant feedback loop within your nervous system, telling your brain what position you are in and what forces are acting upon your body at any given point in time. [1]
Our bodies’ central nervous system and specific soft tissues, including muscles, tendons, and ligaments, work together to aid proprioception.
The receptors in our tissues (proprioceptors) send a signal to the spinal cord through a sensory neuron. They sense and communicate information about the limb velocity and movement, load on a limb, and when a joint is at a specific position. The sensory neuron passes the message back to the motor neurons that control our limb muscles. Fascinating, isn’t it?
Loss of proprioception
An impairment (temporarily caused by drinking too much alcohol or permanently caused by some medical condition) of the proprioception can hinder us from performing the simplest activities.
In his book, Sacks (1985) explains Christina’s case of experiencing the loss of perception. This is how Christina describes her own plight.
“I feel my body is blind and deaf to itself… It has no sense of itself.”
Can you imagine what it must feel like? You are alive, yet you can’t do what you want with your body. You have no sense of how to move your limbs, and you are just flailing around. Think about what happens when the nerves in, say, the muscles of your eyeballs are no longer functioning as it should. How does that affect what you see?
To compensate for this loss, Christina used her other senses to regain a “sense” of her body. Instead of intuitively knowing where her arm was, she used her vision to locate it, and eventually control it. Over time, she made incredible progress. She ‘developed elegant but clearly artificial postures that become her second nature.’ She also experiences some sensations when she feels the breeze on her arms or face.
But when Chistina sees a video of her previous self, she is unable to recognize herself.
“I can’t identify with that graceful girl anymore! She’s gone, I can’t remember her, I can’t even imagine her. It’s like something’s been scooped right out of me, right at the centre . . . that’s what they do with frogs, isn’t it? They scoop out the centre, the spinal cord, they pith them … That’s what I am, pithed, like a frog . . . Step up, come and see Chris, the first pithed human being. She’s no proprioception, no sense of herself — disembodied Chris, the pithed girl!’
Sacks laud her for her bravery, her will, and her tenacity, calling her a heroine of neurology. But he also claims she is ‘still and forever, she remains defective and defeated.’
I was taken by a wave of sadness as I read this. While I found Christina’s progress admirable, I couldn’t help but feel unsettled by what her life constituted of. Defective is not a word anyone would or should label themselves as. It’s also not a situation that can be explained easily and one that garners natural empathy. How can she explain to the people around her what she is going through?
My research led me to another story that of Ian Waterman. He contracted a disease of the nervous system so rare that it led to the loss of proprioception. In 1998, BBC Horizon made a documentary titled ‘The Man Who Lost His Body,’ detailing Ian’s progress (He perfected a new way of initiating and controlling movement).
So, why bother knowing all of this?
I believe a deeper understanding of our bodies and our environment helps us make better decisions. We can enhance proprioception through movement, exercises, and yoga (this gives me all the more reason to sweat on the yoga mat every day).
It also brings to our awareness of the miracles that we take for granted. Today, I have a lot more to feel grateful for. 😄
