Consider the transduction of touch sensation. Merkel’s Discs are touch receptors located superficially and are (largely) slow adapting (for the purposes of this question you can consider
them to be purely slow adapting receptors). A small needle is slowly pressed against the skin of a finger, gradually increasing pressure over 7 seconds, before rapid retraction....The application of these needles to the finger is made in an individual unaware this will happen. As well as retracting their finger rapidly, the individual’s heartbeat accelerates, pupils dilate, they feel a flush of blood to their muscles, and their hairs on their neck and arms stand erect. Which branch of the nervous system is responsible for these effects? After realizing the finger prick was just part of a curious researcher, they feel relieved but the physiological responses persist. What could result in this persistence?