The highest degree of pain localization comes from which of the following?: (A) Simultaneous stimulation of free nerve endings and tactile fibers, (B) Stimulation of free nerve endings by bradykinin, (C) Nerve fibers traveling to the thalamus by way of the paleospinothalamic tract, (D) Stimulation of d-type A fibers
Answer is A. In general, the sensation of pain is poorly localized. However, when a tactile receptor and a pain receptor are stimulated simultaneously, the pain sensation is localized with greater accuracy.