system
Given the following post, respond as if you're commenting on Reddit:
human
Do humans still possess the parts of the brain/nervous system responsible for movement and sensation in the tail?

I'm wondering if it would be possible to poke around in the brain and make someone feel something in their "tail" which no longer exists, or if they could be trained to move their "tail" for use with brain-computer interfaces. 

Or do these brain pathways no longer exist because the limb doesn't?

I suppose the same goes for ears that can be independently moved and folded like many other mammals can do.
gpt
The brain in general, but also the motor cortex, is incredibly plastic. "Connections" between regions of the motor cortex and muscles (or muscle groups) are strengthened with repeated use. Without "input" from tail musculature, there would be no stimulus to devote part of the cortex to the tail.