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In lecture we’ve learned that actions potentials are the “common currency” in the body; they are the same throughout the nervous system. These action potentials only produce different out comes depending on their pathway. We hear because there are motor receptors in the ear that propagate the action potential to a specific area in the brain. This is how all our senses are differentiated.

I was recently reading an article on proprioception; more specifically a disease that resulted in the loss of it. Proprioception, termed the “sixth sense”, is the unconscious perception of movement and spatial orientation arising from stimuli within the body itself. It is the sensory feedback mechanism for motor control and posture. “Proprioception provides information on the physics of the body, the momentary distribution and dynamics of forces acting on the limbs and their highly nonlinear interactions”.
           Loss of proprioception is rare and is caused by degeneration of sensory nerves from the neck down, but spares the motor neurons. Someone with this disease is not capable of feeling whether their body is moving and any bodily movements are elicited uncontrolled reflexes. However, “in the case of Ian Waterman… his strong will and memory of his body enabled him to learn to gradually control and guide his movements with his eyes”, but he was unable to move when he could not see his body.

         This concept raises many questions about the placidity of the sensory pathways we learned about earlier. From this specific case it would appear that the loss of certain pathways, through the degradation of those pathways receptors, results in the body forming new pathways as needed. And while this may not be a new sense, in that there are no new receptors. However earlier we differentiated our senses on their pathways (the receptors used, where they traveled in the central nervous system and where their eventual output was) in order that account for the fact that all action potentials are the same. While I’m not entirely sure that this is even plausible, it would appear from this line of reasoning that changing the pathway actually forms a new sense (sense in the way we currently are defining it).