How to Explain Phantom Limbs?

To understand phantom limbs, we have to talk a little bit about the nervous system. If you tap the palm of your right hand and just tap it gently, you can feel that. But what you're actually doing is underneath the surface of your hand there are pressure receptors. The ending of them, the dendrite if you will, has a specialized receptor that when it's compressed it causes the neuron to fire. That sensation or that firing is carried by the sensation and it goes to the spinal cord then up to the brain into the primary sensory cortex.