Sqaska

A team, including scientists from the Unilever company, have identified a class of nerve fibres in the skin which specifically send pleasure messages.

And people had to be stroked at a certain speed - 4-5cm per second - to activate the pleasure sensation.
For many years, scientists have been trying to understand the mechanisms behind how the body experiences pain, and the nerves involved in conveying those messages to the brain.
This is because people can suffer a great deal.
Neuropathy, where the peripheral nervous system is damaged, can be very painful and sometimes the messaging system goes wrong a people feel pain even when there is no cause.