How does my brain know that a sensation is coming from my finger, as opposed to my foot? Don’t all the nerve endings eventually join into a single point of entry into my brain?

Question

Let’s say I touch a piece of hot apple pie. My finger knows it’s warm. The sensation from my finger travels to my wrist, where the nerve endings from my fingers / hand join up. Then the sensation travels up my arm, to my torso, to my spine, where all the other nerves from my feet and hands and stomach and legs all join.

Are there individual paths of fibers that remain distinct all the way into the brain? is there a unique ‘signature’ that lets the brain know where a certain nerve signal is coming from?

In: Biology

Answer 1

The fibers don’t just stay distinct, there are individual single cells conducting the stimulus. There’s a single cell travelling all the way down from the brain to some part on the extremities of the body. This gets even more crazy when you consider this is true in blue whales and would have been true for dinosaurs too….which means various neuron cells have lengths measured in tens of meters

http://blog.ketyov.com/2012/05/what-is-longest-axon.html