How is a phantom limb and a sensory homunculus linked?

Answer 1

V. Ramachandran desribes a bit of this in his book "The Emerging Mind".

The Penfield-Homunculus is not an exact replica of the body, because the face is located directly besides the hand. Therefore, when a person is missing one arm, the neurons can cross-link, that is when they don't receive any input they form connections with the nearest area - in this case the face.

This is why people with phantom limbs sometimes feel their missing hand when their face is touched, another example is that when the face is stimulated with ice cubes, they feel as if the phantom limb got cold.

Answer 2

Phantom limb sensation refers to feeling in a limb that no longer exists, while the sensory homunculus is a map of the body's sensory receptors in the brain. The brain's map may still perceive sensations in the missing limb leading to phantom limb sensations. Both concepts relate to how the brain processes sensory information, even when there's a discrepancy between the physical body and the brain's perception.