Practice: Hyperhidrosis is a condition characterized by excessive sweating from some region of the body. Hyperhidrosis is sometimes treated by injections of botulinum toxin (a.k.a. “BoTox”) into the affected sweaty area. Botulinum toxin reduces sweating from the treated area by inhibiting the neurons that cause sweating. Which of the following types of neurons are inhibited by botulinum toxin?