Psychophysical studies that find a mathematical relationship between stimulus intensity and pain intensity are often cited as supporting evidence for the assumption that pain is a primary sensation subserved by a direct communication system from skin receptors to pain centre. A simple psychophysical function, however, does not necessarily reflect equally simple neural mechanisms. Activities in the central nervous system, such as memories of earlier cultural experience, may intervene between stimulus and sensation and invalidate any simple psychophysical ‘law’. The use of laboratory conditions that minimize such activities or prevent them from ever coming into play reduces the functions of the nervous system to those of a fixed-gain transmission line. It is under these conditions that psychophysical functions prevail.
Maybe not the most up-to-date information, but a relatively accessible overview of the major theories, definitions, and treatments of pain (and more specifically chronic pain). It is written through a compassionate lens, is honest in admitting the faults and gaps in our scientific understanding of pain, and is critical of archaic theories that lean towards victim-blaming.
A good read for anyone who is actively devising their own treatment plan to cope with chronic pain.
Highly interesting and informative. Complex in places (Undergraduate Level). Published in the 1980s, perhaps more progress has been made since then. A good start, nevertheless. Recommended.