Blood pressure and the perception of illusive pain

in Psychophysiology (2016), 53(8), 1282-1291

Numerous studies have documented an inverse relationship between blood pressure and sensitivity to experimental nociceptive stimulation. The present study aimed to investigate possible associations ... [more ▼]

Numerous studies have documented an inverse relationship between blood pressure and sensitivity to experimental nociceptive stimulation. The present study aimed to investigate possible associations between blood pressure and the occurrence and intensity of paradoxical pain induced by the thermal grill paradigm. Thirty-one healthy subjects were stimulated three times for 1 minute with the non-noxious temperatures of 15°C and 41°C set at the interlaced cold and warm bars of a water bath-driven thermal grill. Blood pressure and heart rate were recorded concomitantly. On account of previous observations of an association between the sensitivity of the cardiac baroreflex and pain perception, this parameter was additionally obtained. Numerical rating scales were used to quantify subjective pain intensity and pain unpleasantness; subjects were classified as responders and non-responders to thermal grill stimulation based on pain intensity ratings. Responders exhibited lower systolic and diastolic blood pressure than non-responders, and inverse linear associations arose between blood pressure and pain intensity and unpleasantness. Baroreflex sensitivity was unrelated to pain ratings. The findings confirmed the hypothesis of a blood pressure dependence of paradoxical pain and support the notion that the cardiovascular and pain regulatory systems interact not only in the processing of pain elicited by noxious input, but also in non-noxiously generated illusive pain. While this finding is not consistent with the assumption of an involvement of the baroreflex system in mediating the observed interaction, psychological traits and neurochemical factors are alternatively considered. [less ▲]

Peripheral and central alterations affecting spinal nociceptive processing and pain at adulthood in rats exposed to maternal separation

in European Journal of Neuroscience (2016)

Inter-individual differences in cardiovascular reactivity and the perception of the thermal grill illusion of pain

Speeches/Talks (2015)

Background: Evidence has been given that there exists a functional relationship between the cardiovascular and the pain regulatory system. Alterations in blood pressure and concomitant changes in ... [more ▼]

Background: Evidence has been given that there exists a functional relationship between the cardiovascular and the pain regulatory system. Alterations in blood pressure and concomitant changes in baroreceptor activation contribute to the modulation of pain sensitivity It could be shown that blood pressure, baroreflex sensitivity, and cardiac vagal tone (indexed by heart rate variability, HRV) are inversely associated to pain sensitivity. We aimed assessing the same cardiovascular parameters in a thermal grill paradigm to test the assumption of a relationship between inter-individual differences in autonomic cardiac control and the perception of the thermal grill illusion of pain (TGI). Methods: All participants (N = 52) were stimulated three times during one minute with the temperatures of 15°C and 41°C set at the interlaced cold and warm bars of the water-bath driven thermal grill. Blood pressure and heart rate were recorded concomitantly. Numerical rating scales (NRS; 0–100) were used to quantify subjective paradoxical pain intensity and pain unpleasantness perceptions. Results: A positive association between cardiac vagal tone and paradoxical pain sensitivity could be revealed. Higher resting HRV, as expressed by higher respiratory sinus arrhythmia (RSA), made it overall more likely to perceive the TGI. In contrast, blood pressure and the susceptibility to the TGI were inversely related. Volunteers displaying higher spontaneous blood pressure values in the first thermal grill stimulation phase did not feel the illusive pain as compared to those who presented significantly lower sympathetic arousal and perceived the TGI. Conclusion: The present physiological findings complement previous evidence of an impact of psychological characteristics on the individual disposition to paradoxical pain perceptions. [less ▲]

Prefrontal activation during placebo analgesia is related to cognitive reappraisal

Poster (2015, September)

Vorwort der Koautoren

in Schmithüsen, Franziska (Ed.) Lernskript Psychologie - Die Grundlagenfächer kompakt (2015)

Pain processing and coping with social stress in rats exposed to adverse early life events

Scientific Conference (2015)

Experimental induction of suffering: why suffering is not the same as unpleasantness

Scientific Conference (2014, October 10)

Introducing the dimension of suffering to mechanically induced phasic and tonic pain

Scientific Conference (2014, October 10)

Vagally mediated heart rate variability is a predictor for the occurrence of the thermal grill-induced pain illusion

Poster (2014, October)

Aim: Unpleasantness and negative affect accompany the sensory experience of pain. Both components of pain are heavily influenced by cognitive and emotional processes. In this framework, alterations in ... [more ▼]

Aim: Unpleasantness and negative affect accompany the sensory experience of pain. Both components of pain are heavily influenced by cognitive and emotional processes. In this framework, alterations in baroreceptor reactivity and concomitant changes in cardiac rhythm and blood pressure related to these processes contribute to the modulation of pain sensitivity. Furthermore, self-regulatory capacity has been shown to play a major role in the regulation of cognitive, affective, and behavioural reactions to adverse contexts. These regulatory mechanisms include adjustment of cardiovascular activity and heavily depend on prefrontal cortical processing. Vagally mediated heart rate variability (HRV) at rest is an indicator of the prefrontally modulated vagal activation and has been used as a psychophysiological marker for self-regulatory capacity. The present study investigated the predictive value of the trait self-regulation in the triggering of the thermal grill-induced pain illusion (TGI). We hypothesized inter-individual differences in paradoxical pain perception to be predicted by self-regulatory capacity in a way that participants displaying lower levels of self-regulation should be more likely to perceive the painful grill illusion than subjects with relatively higher self-regulation ability. Methods: A total of 54 healthy participants were recruited among university students and staff. A custom-built, water-bath driven thermal grill device, with interlaced cold and warm glass tubes, was used for the induction of the TGI. A pre-set temperature combination of 15°C and 41°C was applied to the palm of the dominant hand with stimulus durations of 1 min. Subsequent control conditions consisted in the interlaced combination of a baseline temperature of 32°C with one of the stimulus temperatures mentioned above. The procedure was repeated three times. The volunteers used numerical rating scales ranging from 0-100 to rate sensory and affective pain perceptions in intervals of 15 seconds. Vagally mediated HRV at rest was assessed prior to the thermal stimulation protocols. Results: Time-domain components of HRV used as graded indicators of parasympathetic activity and of the extent of self-regulation significantly predicted the possibility of an occurrence of pain and unpleasantness sensations in response to thermal grill stimulation (p <.05). Participants characterized in this way were more likely to express paradoxical pain than subjects not displaying similar levels of HRV. Conclusion: The present results support previous findings indicating an impact of several psychological traits on the individual disposition to paradoxical pain perceptions. Self-regulation ability, operationalized as vagally mediated heart rate variability, can partially explain the probability of perceived pain in response to non-noxious thermal grill stimulation. [less ▲]

Beep Tones Attenuate Pain following Pavlovian Conditioning of an Endogenous Pain Control Mechanism

in PLoS ONE (2014), 9(2), 88710

Heterotopic noxious counter-stimulation (HNCS) is commonly used to study endogenous pain control systems. The resulting pain inhibition is primarily based on spinal cord-brainstem loops. Recently ... [more ▼]

Heterotopic noxious counter-stimulation (HNCS) is commonly used to study endogenous pain control systems. The resulting pain inhibition is primarily based on spinal cord-brainstem loops. Recently, functional imaging studies have shown that limbic structures like the anterior cingulate cortex and amygdala are also implicated. Since these structures are involved in learning processes, it is possible that the HNCS-induced pain inhibition may depend on specific cues from the environment that have been associated with pain reduction through associative learning. We investigated the influence of Pavlovian conditioning on HNCS-induced pain inhibition in 32 healthy subjects by using a differential conditioning paradigm in which two different acoustic stimuli were either repeatedly paired or unpaired with HNCS. Series of noxious electrical pulse trains delivered to the non-dominant foot served as test stimuli. Diffuse noxious inhibitory control (DNIC)-like effects were induced by concurrent application of tonic HNCS (immersion of the contralateral hand in ice water). Subjective pain intensity and pain unpleasantness ratings and electromyographic recordings of the facial corrugator muscle and the nocifensive RIII flexion reflex were used to measure changes in pain sensitivity. HNCS induced significant pain and reflex inhibitions. In the post-conditioning phase, only the paired auditory cue was able to significantly reduce pain perceptions and corrugator muscle activity. No conditioned effect could be observed in RIII reflex responses. Our results indicate that the functional state of endogenous pain control systems may depend on associative learning processes that, like in the present study, may lead to an attenuation of pain perception. Similar albeit opposite conditioning of pain control mechanisms may significantly be involved in the exacerbation and chronification of pain states. [less ▲]