Proprioception: Balance and Phantom Limbs

One theme that unites the three topics covered in this chapter—balance, phantom limbs, and prosthetics—is proprioception. Proprioception is our sense of our own body. We need it to stay balanced, and it has gone awry when we’re experiencing phantom limbs, but current technological innovations are actually taking advantage of our ability to perceive phantom limbs to create active prosthetic limbs that can be thought-controlled!

Another idea that we rely on to understand how our brain processes balance and perceives phantom and prosthetic limbs is cue combination. Cue combination is an idea that comes up again and again as we study perception. The idea is this: while it’s simplest to talk about one thing at a time—just visual perception or just auditory perception—the reality is that we’re always experiencing multiple senses at the same time. As I type, I both feel and hear the keys on my keyboard; as I talk, I feel myself speak and I hear myself speak. Our brains are always integrating cues from multiple senses as they try to figure out what’s going on in the world.

Cue conflict is related to cue combination: it is what happens when the cues we’re getting from different senses don’t fit together. What do we do when we get conflicting information about our environment? In the case of motion sickness, we feel ill. If we hear a delayed copy of our own voice as we try to speak, we stop being able to speak correctly. Or, in the case of the rubber hand illusion, our brains might just decide to believe a reliable cue and ignore the conflicting cue.

This chapter was created by Iqra Ismail, Drew Kampmeier,  Nika Khadem, Kyle Knudsen, Nathaniel Luers, Anna Maunu, Mehmaz Mirhosseini, Ryleigh Orning,