Context: Wilhelm Erb's (1874) "intensive" theory, that a pain signal can be generated by intense enough stimulation of any sensory receptor, has been soundly disproved. Some sensory fibers do not differentiate between noxious and non-noxious stimuli, while others, nociceptors, respond only to noxious, high intensity stimuli. At the peripheral end of the nociceptor, noxious stimuli generate currents that, above a given threshold, begin to send signals along the nerve fiber to the spinal cord. The "specificity" (whether it responds to thermal, chemical or mechanical features of its environment) of a nociceptor is determined by which ion channels it expresses at its peripheral end. Dozens of different types of nociceptor ion channels have so far been identified, and their exact functions are still being determined.

Question: What type of signal can be generated by intense enough stimulation of any sensory receptor?
Answer: pain

Question: What types of stimuli can't some sensory fibers differentiate between?
Answer: noxious and non-noxious

Question: What type of stimuli do nociceptors response to?
Answer: noxious, high intensity

Question: What does stimuli generate to send signals along a nerve fiber?
Answer: currents

Question: How many different types of ion channels have so far been identified?
Answer: Dozens

Question: Who came up with the intensive theory in 1784?
Answer: Unanswerable

Question: What did Wilhelm Erb come up with in 1784?
Answer: Unanswerable

Question: What is Erb Wilhelm's intensive theory?
Answer: Unanswerable

Question: What happened to Erb Wilhelm's theory?
Answer: Unanswerable

Question: How many different types of nociceptor chemical channels have been identified?
Answer: Unanswerable