Mechanisms of neuropathic pain: Nerve, brain, and psyche: Perhaps the dorsal horn but not the sympathetic system

Neuropathic Pain Syndrome Displayed by Malingerers

“…Thus, the label CRPS I is by default; a left over nickname that lacks evidential medical power. It is assumed to be a syndrome, or even a discrete disease, when in fact it is a listing of non-specific symptoms and signs awaiting differential diagnosis, which is traditionally bypassed (Ochoa and Verdugo, 2001; Ochoa, 2003; Loeser, 2005). Neurophysiological testing is dismissed as futile because it is predictably normal, even in presence of displayed weakness, paralysis or sensory loss.…”

“…The sympathetically maintained pain hypothesis can be dismissed on the grounds of negative current scientific medical evidence (for review see Ochoa, 1999; Ochoa and Verdugo, 2001). In turn, the hypothesis that these patients harbor subclinical neuropathology of peripheral unmyelinated fibers is not supportable by reliable data.…”

Functional Neuroanatomy of Pain

“…Similarly, intracutaneous applications of adrenaline and phenylephrine have been shown to increase spontaneous pain and allodynia in the affected area of PHN patients (Choi and Rowbotham 1997). However, most of the patients do not demonstrate significant benefit from various sympathicolytic procedures (Nurmikko et al 1991;Kingery 1997;Attal and Bouhassira 1999;Ochoa 1999;Ochoa and Verdugo 2001;Mailis and Furlan 2003), suggesting that the role of the sympathetic nervous system may have been overemphasized. Moreover, Mailis and Furlan (2003) point out that the complications of the sympathicolytic procedure may be significant, in terms of both worsening the pain or producing a new pain syndrome.…”

Quantifying sensation: “Look Back in Allodynia”

“…reported to the Society of Neurosciences (Cline and Ochoa, 1986) and then to the journal Brain (Cline et al, 1989) the first direct single fiber electrophysiological demonstration of C nociceptor sensitization as one basis for abnormally augmented heat pain and mechanical pain perceptions, in patients. Beyond doubt, nociceptors evoke pain (see Ochoa et al, 1996; see also Ochoa and Verdugo, 2001). Sensitized nociceptors respond with reduced threshold to adequate stimuli.…”

“…Res. ; Ochoa and Verdugo, 2001). When Roberts introduced his ingenious theory on pathogenesis of sympathetic neuropathic pains, he strongly leaned on hypothetical sensitization of central , second‐order, pain‐signaling spinal neurons, and very effectively promoted the term allodynia for use of both experimental scientists and pain clinicians.…”