How can the Brain tell a sensation in the index finger apart from one in the middle finger?

Question

As they’re ultimately both being communicated via the median nerve

In: 5

Answer 1

Nerves are bundles of cables, but each cable is still separate. In fact the ‘cables’ are actually individual neurons. The longest neurons in your body are bundled into the sciatica nerve, and they go from the base of your spine all of the way to your big toe.

From the spinal cord, the signals go on up to your brain and eventually reach sensory cortex. This is a strip of brain tissue about where a headband sits, and information from the different parts of your body are organized along it in a kind of map.

Your fingers in particular have a lot of brain dedicated to them as they’re so sensitive, and each one has its own separate bit of tissue.

You can see what this sensory body map looks like on your brain here, it’s called a cortical homunculus: https://en.wikipedia.org/wiki/Cortical_homunculus?wprov=sfla1