Offset analgesia: A temporal contrast mechanism for nociceptive information

Abstract

Temporal filtering of afferent information is an intrinsic component of the processing of numerous types of sensory information. To date, no temporal filtering mechanism has been identified for nociceptive information. The phenomenon of offset analgesia, the disproportionately large decrease in perceived pain following slight decreases in noxious thermal intensity, however, suggests the existence of such a mechanism. To test the hypothesis that a temporal filtering mechanism is engaged during noxious stimulus offset, subjects rated heat pain intensity while stimulus fall rates were varied from -0.5 to -5.0 degrees C/s. In the absence of a temporal filtering mechanism, pain intensity would be expected to decrease in direct proportion to the stimulus fall rate. However, psychophysical fall rates were considerably faster than stimulus fall rates, such that subjects reported no pain while stimulus temperatures were clearly within the noxious range (47.2 degrees C). In addition, paired noxious stimuli were presented simultaneously to determine if offset analgesia evoked by one stimulus could inhibit pain arising from a separate population of primary afferent neurons. Pain ratings were significantly lower than those reported from two constant 49 degrees C stimuli when offset analgesia was induced proximal to, but not distal to, a second noxious stimulus. These asymmetric spatial interactions are not readily explained by peripheral mechanisms. Taken together, these findings indicate that offset analgesia is mediated in part by central mechanisms and reflect a temporal filtering of the sensory information that enhances the contrast of dynamic decreases in noxious stimulus intensity.

Role of endogenous pain modulation in chronic pain mechanisms and treatment

“…Typically, a drop in pain rating immediately after end of the transient is seen, representing pain inhibition. 95 Suprathreshold magnitude estimation of experimental pain is a simple-to-perform protocol, shown to be relevant in predicting acute postoperative pain. 1 The text will now update on the CPM phenomena, regarding methodology, mechanism, and clinical applications in diagnosis and in therapy for pain.…”

Altered Central Sensitization and Pain Modulation in the CNS in Chronic Joint Pain

“…A slight increase in perceived pain occurred from the first to the second stimulus, and the third stimulus caused a significantly lower pain intensity compared with the first stimulus (although they had the same stimulus temperature). Studies have investigated the mechanisms involved in offset analgesia, and Yelle et al [72] concluded that offset analgesia is partly mediated by central mechanisms. In contrast, Derbyshire and Osborn [73] proposed that offset analgesia was caused by peripheral mechanisms.…”

Effect of Static and Dynamic Heat Pain Stimulus Profiles on the Temporal Dynamics and Interdependence of Pain Qualities, Intensity, and Affect

“…These subjective pain dimensions wax and wane in the continued presence of a noxious stimulus (Greene and Hardy 1962). This temporal variability can occur due to peripheral and central phenomenon such as nociceptor adaptation (Torebjörk et al 1984) and central summation (Ochoa and Torebjörk 1989;Price and Dubner 1977;Torebjörk and Ochoa 1980), descending inhibition (Bouhassira et al 2003) or due to a change in stimulus properties (Davis and Pope 2002;Grill and Coghill 2002;Yelle et al 2008). However, the temporal pattern of specific pain qualities and their relationship with pain and affect is not well understood.…”

“…Effect of static and dynamic heat pain stimulus profiles on the temporal dynamics and interdependence of pain qualities, intensity, and affect. J Neurophysiol 100: 1706 -1715, 2008. First published August 13, 2008 doi:10.1152/jn.90500.2008.…”