Pain and the defense response: structural equation modeling reveals a coordinated psychophysiological response to increasing painful stimulation

Abstract

The defense response theory implies that individuals should respond to increasing levels of painful stimulation with correlated increases in affectively mediated psychophysiological responses. This paper employs structural equation modeling to infer the latent processes responsible for correlated growth in the pain report, evoked potential amplitudes, pupil dilation, and skin conductance of 92 normal volunteers who experienced 144 trials of three levels of increasingly painful electrical stimulation. The analysis assumed a two-level model of latent growth as a function of stimulus level. The first level of analysis formulated a nonlinear growth model for each response measure, and allowed intercorrelations among the parameters of these models across individuals. The second level of analysis posited latent process factors to account for these intercorrelations. The best-fitting parsimonious model suggests that two latent processes account for the correlations. One of these latent factors, the activation threshold, determines the initial threshold response, while the other, the response gradient, indicates the magnitude of the coherent increase in response with stimulus level. Collectively, these two second-order factors define the defense response, a broad construct comprising both subjective pain evaluation and physiological mechanisms.

Descriptors of Pain Sensation: A Dual Hierarchical Model of Latent Structure

“…This mirroring of pain neurophysiology in the lexicon of pain sensations is hitherto unreported in the pain literature, although there is comparable research on the correspondence between latent structure and psychophysiology of pain. 7, 8 We do not mean to imply that groupings of pain descriptors are direct projections of neurophysiological organization or, for that matter, that they influence neurophysiological structure. Moreover, our findings of congruence have been restricted to the English lexicon of pain.…”

Affective modulation of eyeblink reactions to noxious sural nerve stimulation: A supraspinal measure of nociceptive reactivity?☆

“…Pain and pain-related reactions are considered defensive responses (e.g., Donaldson et al, 2003). Noxious stimuli (harmful or potentially harmful stimuli that activate Aδ and/or C-fibers) elicit a repertoire of motoric (e.g., withdrawal reflexes), autonomic (e.g., HR acceleration), neuroendocrine (e.g., epinephrine release), and subjective (e.g., pain) reactions that motivate escape and protect an organism from harm.…”

Establishing a Link Between Heart Rate and Pain in Healthy Subjects: A Gender Effect

“…It is well established that a painful stimulus does produce many physiologic changes; however the slope of the relationship between pain and physiologic responses has been shown to vary noticeably between individuals. 5 Consequently, the validity of this principle and its current application have been rightfully criticized mostly by the absence of good literature exposing the relationship between HR and pain and allowing the generalization of these findings to clinical pain. 17 Moreover, HR is subjected to many sources of variations that may affect its association with pain.…”