[Show abstract][Hide abstract] ABSTRACT: In healthy subjects with high hypnotisability (highs) under hypnosis, subjectively effective suggestions for analgesia abolish the increases in blood pressure associated with cold pressor test (cpt) by reducing the peripheral vascular resistance. The aim of the present study was to investigate the effects of the suggestions of analgesia on the responses to cpt in healthy highs (n = 22) and in low hypnotisable participants (lows, n = 22) out of hypnosis. Cpt was administered without (CPT) and with suggestions for analgesia (CPT+AN). Psychophysical (pain intensity, pain threshold, cpt duration (time of immersion) and pain tolerance, defined as the difference between cpt duration and pain threshold), respiratory (amplitude and frequency) and autonomic variables (tonic skin conductance, mean RR interval (RR = 1/heart rate), blood pressure, skin blood flow) were studied. The suggestions for analgesia increased cpt duration and RR in both groups, but decreased pain intensity and enhanced pain threshold only in highs; in both groups they did not modulate systolic blood pressure, tonic skin conductance and skin blood flow; thus, increased parasympathetic activity appears responsible for the heart rate reduction induced by suggestions in both groups. In conclusion, our findings show that suggestions modulate pain experience differentially in highs and lows, and are partially effective also in lows. We hypothesize that the mechanisms responsible for the efficacy of suggestions in healthy lows may be involved also in their efficacy in chronic pain patients with low hypnotisability.
PLoS ONE 10/2013; 8(10):e75023. · 3.53 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The aim of the study was to test the efficacy of pain imagery as a function of hypnotisability and of the activity of Behavioral Inhibition/Activation Systems. Questionnaires of imagery abilities (Betts) for the visual, cutaneous and organic modalities, absorption in cognitive tasks (TAS), proneness to inhibit stressful/painful experience/seek out positive experiences (BIS BAS), trait anxiety (STAI-Y2) and psychological well-being (PWB) were administered to 21 subjects with high hypnotisability (highs) and 21 subjects with low hypnotisability (lows). Self-reports of pain intensity and of neutral tactile perception were collected during imagery of nociceptive (Pain) and neutral tactile stimulation (NT). ECG and Skin Conductance were recorded. Highs exhibited greater imagery abilities, absorption, Behavioural Inhibition System Activity and Psychological Well-Being with respect to lows. They reported lower scores of pain intensity than of tactile perception, while in lows Pain and NT scores did not differ. However, controlling for BAS, but not for BIS, revealed differences in the efficacy of pain imagery between highs and lows. Heart rate decreased in both tasks and groups; heart rate variability and skin conductance did not change significantly during imageries. Our findings suggest that the Behavioral Inhibition/Activation Systems interact with imagery abilities reducing the efficacy of pain imagery and prompt investigation of possible similar interactions in the modulation of physically-induced experimental pain and of chronic pain in the general population.
[Show abstract][Hide abstract] ABSTRACT: Mean values and the spectral variability of heart rate (HRV), blood pressure, and skin blood flow were studied in high and low hypnotizable subjects during simple relaxation. Similar subjective relaxation was reported by highs and lows. A parasympathetic prevalence (indicated by a higher High-Frequency component of HRV and a lower High/Low-Frequency ratio) and lower renin-angiotensin activity (indicated by a lower Very-Low-Frequency component of HRV) could be attributed to highs with respect to lows. Hypnotizability did not affect blood pressure and its variability and modulated the skin blood flow across the session only in lows. The findings confirm that relaxation cannot be defined solely on cardiovascular parameters and also indicate that hypnotizability modulates cardiovascular activity during simple relaxation and suggest it may have a protective role against cardiovascular disease.
International Journal of Clinical and Experimental Hypnosis 10/2012; 60(4):383-96.
[Show abstract][Hide abstract] ABSTRACT: Subjects with high hypnotizability scores (Highs) have been considered more prone to experience negative affect and more vulnerable to its autonomic effects with respect to low hypnotizable individuals (Lows). The aim of the study was to analyze the subjective experience, tonic skin conductance (SC), respiratory frequency (RF), heart rate (HR) and heart rate variability (HRV) of healthy Highs and Lows during a long-lasting, emotionally neutral task (Session R, 46 subjects) and a moderately threatening one (Session T, 35 subjects). At the end of the relaxing Session R, all participants reported an increased relaxation. At the end of the threatening Session T, only 20 subjects reported a decreased relaxation (effective T: eT subsample). Highs and Lows of this subsample reported a similarly reduced relaxation and showed a similarly increased skin conductance. HR and HRV did not differ between the two sessions and between Highs and Lows. Among the subjects not reporting decreased relaxation at the end of Session T (ineffective T: iT subsample, n=15), relaxation was deeper and associated with lower skin conductance in Highs, although HR and HRV did not differ between Highs and Lows. All together, the results do not support the hypothesis of higher proneness of Highs to experience negative affect and to exhibit the autonomic correlates of negative emotion.
International journal of psychophysiology: official journal of the International Organization of Psychophysiology 01/2012; 84(1):59-64. · 3.05 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: It has been shown that, in subjects with high hypnotizability (Highs), imagined somatosensory stimulation can involuntarily activate the neural circuits involved in the modulation of reflex action. In this vein, aim of the study was to investigate whether the imagery of nociceptive stimulation in one leg may produce both subjective experience of pain and congruent postural adjustments during normal upright stance. The displacement of the centre of pressure (CoP) was studied during imagery of leg pain (LP) and during the control conditions of imagery of tactile stimulation of the same leg and of throat pain (TP) in 12 Highs and 12 low hypnotizable subjects (Lows). The results showed that the vividness of imagery was higher in Highs than in Lows for all tasks and that only Highs reported actually feeling pain during LP and TP. Congruently, during LP only Highs displaced their CoP towards the leg opposite to the one that was the object of painful imagery and increased their CoP mean velocity and area of excursion. Since the Highs' postural changes were not accounted for only by vividness of imagery and perceived pain intensity, high hypnotizability is apparently responsible for part of the postural effects of pain imagery.
Experimental Brain Research 11/2011; 216(3):341-8. · 2.17 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Focused attention typically enhances neural nociceptive responses, reflected electroencephalographically as increased amplitude of pain-evoked event-related potentials (ERPs). Additionally, pain-evoked ERPs are attenuated by hypertension and baroreceptor activity, through as yet unclear mechanisms. There is indirect evidence that these two effects may interact, suggesting that baroreceptor-related modulation of nociception is more than a low-level gating phenomenon. To address this hypothesis, we explored in a group of healthy participants the combined effects of cue-induced expectancy and baroreceptor activity on the amplitude of pain-evoked ERPs. Brief nociceptive skin stimuli were delivered during a simple visual task; half were preceded by a visual forewarning cue, and half were unpredictable. Nociceptive stimuli were timed to coincide either with systole (maximum activation of cardiac baroreceptors) or with diastole (minimum baroreceptor activation). We observed a strong interaction between expectancy and cardiac timing for the amplitude of the P2 ERP component; no effects were observed for the N2 component. Cued stimuli were associated with larger P2 amplitude, but this effect was abolished for stimuli presented during baroreceptor activation. No cardiac timing effect was observed for un-cued stimuli. Taken together, these findings suggest a close integration of cognitive-affective aspects of expectancy and baroreceptor influences on pain, and as such may cast further light on mechanisms underlying mental and physiological contributions to clinical pain.
[Show abstract][Hide abstract] ABSTRACT: Body sway and locomotion are differentially modulated in high (highs) and low (lows) hypnotizable subjects undergoing alteration of visual and neck/leg proprioceptive inputs. The study's aim was to investigate whether partial impairment of vestibular information due to backward head extension affects postural (Study 1) and locomotor behavior (Study 2) differentially in highs and lows. Results showed that, at variance with the visual and proprioceptive modalities, vestibular inactivation did not induce major differences between the 2 groups, with the exception of improvement in walking straight across consecutive trials, which was observed only in highs. The article presents an overview of the structures and mechanisms possibly involved in the observed hypnotizability-related differences in motor control and suggests that hypnotic susceptibility might be a relevant factor in neuro-rehabilitative treatments because it accounts for part of the variability in the sensorimotor self.
International Journal of Clinical and Experimental Hypnosis 07/2010; 58(3):329-44.
[Show abstract][Hide abstract] ABSTRACT: Hypnotizability is a cognitive trait modulating some physiological responses to cognitive and physical stimulation also in the normal awake state and in the absence of specific suggestions. Aim of the study was the characterization of the cardiovascular correlates of deep pain induced by nociceptive pressor stimulation without (PAIN) and with (AN) suggestions for analgesia, pain imagery/perception (IM) and mental computation (MC) in not hypnotized highly (Highs) and low (Lows) hypnotizable healthy subjects of both genders. The subjective experience of pain intensity, relaxation and task related fatigue were measured through a structured interview. Heart rate, blood pressure, skin blood flow and respiratory activity were monitored throughout the experimental session. Only Highs perceived lower pain intensity during AN with respect to PAIN and were able to perceive pain during IM. Heart rate decreased during PAIN, increased during MC and did not change during AN and IM in both groups. On the whole, the haemodynamic response consisted of decreased systolic/mean blood pressure and maximum skin blood flow together with increased diastolic blood pressure/minimum skin blood flow in both groups during all conditions. Scarce differences were observed between Highs and Lows (in systolic blood pressure during IM and in respiratory amplitude during PAIN, AN and IM, modulated by gender). The results indicate that in not hypnotized subjects hypnotizability is not associated with relevant differences in the autonomic responses to deep pain, suggestions for analgesia, pain imagery/perception and cognitive load.
Brain research bulletin 03/2010; 82(1-2):65-73. · 2.97 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: In highly hypnotizable individuals (highs), postural control is more independent of sensory information than in low hypnotizable subjects (lows). The aim of the study was to find out whether locomotion is also less affected in highs than in lows by visual suppression and changes in the neck proprioceptive input. Eighteen highs and 20 lows were asked to walk straight ahead, blindfolded, in basal conditions (face forward), during real and imagined right/left head rotation and mental computation. Highs detected deviations from the straight trajectory better than lows. Their walking direction was more straight during basal conditions and less influenced than the lows' one by mental computation and real/imagined rotation of the head. The results confirm highs' lower dependence on sensory inputs, although this cannot be definitely attributed to a better internal representation of space or to higher behavioral automaticity.
International Journal of Clinical and Experimental Hypnosis 01/2010; 58(1):122-35.
[Show abstract][Hide abstract] ABSTRACT: In this study, we aimed at comparing the effect of the social versus the physical enrichment of the environment on inflammatory pain. Hence, a rat model of carrageenan-induced knee inflammation was used. Four housing conditions were investigated: a physically enriched environment (PE), a socially enriched environment (SE), an enriched environment (EE) (i.e. physically and socially enriched) and a restricted environment (RE) (i.e. non-physically or socially enriched housing). Mechanical allodynia was assessed using the von Frey test preoperatively and at day post-operative (DPO) 1, 3, 7, 10, 14, 17, 21, 24 and 28. Besides, anxiety was evaluated at DPO29, using the Elevated Plus-Maze test. Results show that RE housing resulted in a duration of mechanical allodynia of 4 weeks and of only 3 weeks in EE housing. Housing in a physically enriched environment also resulted in a reduction of the duration of mechanical allodynia of 1 week. Finally, if housed in a SE, the mechanical allodynia lasted for 3 weeks and an half. From these data, we conclude that both physical and social aspects of the environment are involved in the reduction of inflammatory pain duration, although the PE has a larger effect than the SE in this experimental setting. Interestingly, an inter-dependent relationship was noted between the PE and SE. Moreover, no significant difference in the rat anxiety was measured between groups, suggesting that the pain outcomes are likely not biased by the mean of potential housing condition-induced anxiety.
Behavioural brain research 11/2009; 208(1):90-5. · 3.22 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Hypnotizability-dependent changes in heart rate and blood pressure in the time domain were studied during low attentional tasks in subjects with high or low hypnotic susceptibility watching a relaxing and an alerting movie. All participants reported relaxation during the former, while only part of them was stressed by the latter. During relaxation hypnotizability did not modulate mean heart rate and blood pressure, but affected the variability of the latter, which indirectly indicates differences in the autonomic pattern associated with the low attentional relaxing movie with respect to simple relaxation and highlighted the hypnotizability-related role of the emotional content associated with a relaxation response. In line with previous studies the results suggested a role for hypnotizability in the control of the vascular resistance.