A B S T R A C T

 There are three types of nerve fibers that are involved in the transmission of pain stimuli: C fibers (slower fibers) for thermal, mechanical and chemical stimuli, A-delta fibers for thermal or mechanical stimuli and A-beta fibers for touch stimuli. Clinically, this is crucial in making an accurate assessment of the pain level experienced by a suffering patient, in indicating the appropriate therapy and studying the response to treatment. The threshold is actually the experience of the patient, whereas the intensity measured is an external event. But often pain investigators tend to define the threshold in terms of the stimuli. Pressure, Thermal, Electrical and LASER are some of the pain induction methods that we have discussed in this article.