The gate control theory of pain asserts that non-painful input closes the nerve "gates" to painful input, which prevents pain sensation from traveling to the central nervous system. The gate control theory of pain describes how non-painful sensations can override and reduce painful sensations. A painful, nociceptive stimulus stimulates primary afferent fibers and travels to the brain via transmission cells. Increasing activity of the transmission cells results in increased perceived pain. Conversely, decreasing activity of transmission cells reduces perceived pain. In the gate control theory, a closed "gate" describes when input to transmission cells is blocked, therefore reducing the sensation of pain. An open “gate” describes when input to transmission cells is permitted, therefore allowing the sensation of pain. First proposed in 1965 by Ronald Melzack and Patrick Wall, the theory offers a physiological explanation for the previously observed effect of psychology on pain perception. Combining early concepts derived from the specificity theory and the peripheral pattern theory, the gate control theory is considered to be one of the most influential theories of pain. This theory provided a neural basis which reconciled the specificity and pattern theories -- and ultimately revolutionized pain research. Although there are some important observations that the gate control theory cannot explain adequately, this theory remains the theory of pain which most accurately accounts for the physical and psychological aspects of pain perception. Willem Noordenbos (1910–1990), a Dutch researcher at the University of Amsterdam, proposed in 1959 a model which featured interaction between small (unmyelinated) and thick (myelinated) fibers. In this model, the fast (myelinated) fibers block the slow (unmyelinated) fibers: "fast blocks slow". Proposed mechanisms When you experience a negative feeling, such as pain from a bump or an itch from a bug bite, a common reaction is an attempt to eliminate the feeling by rubbing the painful bump or scratching the itchy bite. Gate control theory asserts that activation of nerves that do not transmit pain signals, called nonnociceptive fibers, can interfere with signals from pain fibers, thereby inhibiting pain. It is proposed that both small-diameter (pain-transmitting) and large-diameter (touch-, pressure-, and vibration- transmitting) afferent nerve fibers carry information from the site of the injury to two destinations in the dorsal horn: 1. Transmission Cells that carry the pain signal up to the brain, and 2. Inhibitory Interneurons that impede transmission cell activity. Activation of transmission cells occurs from both excitatory small-diameter and excitatory