Dilepton decay from excited states in 28Si populated via different isospin entrance channels

A four-stage model of pain processing was proposed, consisting of pain sensation intensity, pain unpleasantness (stage 1 affect), suffering (stage 2 affect), and pain behavior. We studied 506 chronic pain patients (230 male and 276 female) using a multivariate statistical technique (LISREL) in order to demonstrate the structural relationship among multiple indicators of pain processing; and to characterize these stages in terms of their interactions. A strong relationship was revealed between the majority of the underlying indicators of each pain processing stage. A linear stage sequence best fitted the relationship between the four stages. Successive stages did not have recursive effects on earlier pain components. A confirmatory LISREL analysis was conducted with an additional sample of 502 chronic pain patients. In this replication analysis the structural equation model consisted of pain intensity, unpleasantness (stage 1 affect), emotional suffering (stage 2 affect), and pain behavior. This study extends the validation of these pain dimensions, as well as the validity of the measure(s) of each separate stage.     

Zatebradine: pharmacokinetics of a novel heart-rate-lowering agent after intravenous infusion and oral administration to healthy subjects

Although high-frequency low-intensity transcutaneous electric nerve stimulation (TENS) has been extensively used to relieve low back pain, experimental studies of its effectiveness have yielded contradictory findings mainly due to methodological problems in pain evaluation and placebo control. In the present study, separate visual analog scales (VAS) were used to measure the sensory-discriminative and motivational-affective components of low back pain. Forty-two subjects were randomly assigned to 1 of 3 groups: TENS, placebo-TENS, and no treatment (control). In order to measure the short-term effect of TENS, VAS pain ratings were taken before and after each treatment session. Also, to measure long-term effects, patients rated their pain at home every 2 h throughout a 3-day period before and 1 week, 3 months and 6 months after the treatment sessions. In comparing the pain evaluations made immediately before and after each treatment session, TENS and placebo-TENS significantly reduced both the intensity and unpleasantness of chronic low back pain. TENS was significantly more efficient than placebo-TENS in reducing pain intensity but not pain unpleasantness. TENS also produced a significant additive effect over repetitive treatment sessions for pain intensity and relative pain unpleasantness. This additive effect was not found for placebo-TENS. When evaluated at home, pain intensity was significantly reduced more by TENS than placebo-TENS 1 week after the end of treatment, but not 3 months and 6 months later. At home evaluation of pain unpleasantness in the TENS group was never different from the placebo-TENS group.(ABSTRACT TRUNCATED AT 250 WORDS)     

Menstrual cycle, beta-endorphins, and pain sensitivity in premenstrual dysphoric disorder.

This study examined pain sensitivity and pain modularity mechanisms (e.g., beta-endorphin levels, blood pressure) in women with premenstrual dysphoric disorder (PMDD; n=27) and healthy controls (n=27) during the follicular and luteal phases of the menstrual cycle. Physiological measures were taken during rest and ischemic pain testing. In both cycle phases, PMDD women (a) displayed lower resting cortisol and beta-endorphin levels and (b) exhibited shorter pain threshold and tolerance times and greater pain unpleasantness ratings during pain. PMDD women also reported greater pain unpleasantness and intensity and had lower beta-endorphin levels in their luteal phase and tended to display higher blood pressure levels at rest and during pain testing. Results suggest that endogenous opioids may be pathophysiologically relevant to PMDD and that the hypothalamic-pituitary-gonadal axis may modulate pain sensitivity in PMDD. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The effect of pain reduction on perceived tension and EMG-recorded trapezius muscle activity in workers with shoulder and neck pain

The study was initiated to evaluate the effect of pain-reducing therapies on factors previously associated with work-related shoulder and neck pain, namely increased muscle activity in the upper trapezius and perceived general tension. Thirty-three women in three groups were assessed before and after an intervention period and by questionnaire 6 months later. The purpose of this study was primarily to investigate associations between upper trapezius muscle activity, perceived general tension and pain, and secondly, to compare effects of individually based physiotherapy and group exercise for workers with shoulder and neck myalgia. All three groups reported a significant alleviation of pain and perceived general tension, while the electromyographically (EMG) recorded upper trapezius muscle activity level remained unchanged or increased. Improvements were similar in all three treatment groups, but individual-based therapies were rated more beneficial on subjective measures. Significant correlation was found between pain and perceived general tension (r = 0.66, p <0.01), while there was no correlation between pain or perceived general tension and recorded muscle activity.     

Congenital thrombophilia

Previous functional imaging studies have demonstrated a number of discrete brain structures that increase activity with noxious stimulation. Of the commonly identified central structures, only the anterior cingulate cortex shows a consistent response during the experience of pain. The insula and thalamus demonstrate reasonable consistency while all other regions, including the lentiform nucleus, somatosensory cortex and prefrontal cortex, are active in no more than half the current studies. The reason for such discrepancy is likely to be due in part to methodological variability and in part to individual variability. One aspect of the methodology which is likely to contribute is the stimulus intensity. Studies vary considerably regarding the intensity of the noxious and non-noxious stimuli delivered. This is likely to produce varying activation of central structures coding for the intensity, affective and cognitive components of pain. Using twelve healthy volunteers and positron emission tomography (PET), the regional cerebral blood flow (rCBF) responses to four intensities of stimulation were recorded. The stimulation was delivered by a CO2 laser and was described subjectively as either warm (not painful), pain threshold just painful), mildly painful or moderately painful. The following group subtractions were made to examine the changing cerebral responses as the stimulus intensity increased: (1) just painful - warm; (2) mild pain - warm; and (3) moderate pain - warm. In addition, rCBF changes were correlated with the subjective stimulus ratings. The results for comparison '1' indicated activity in the contralateral prefrontal (area 10/46/44), bilateral inferior parietal (area 40) and ipsilateral premotor cortices (area 6), possibly reflecting initial orientation and plans for movement. The latter comparisons and correlation analysis indicated a wide range of active regions including bilateral prefrontal, inferior parietal and premotor cortices and thalamic responses, contralateral hippocampus, insula and primary somatosensory cortex and ipsilateral perigenual cingulate cortex (area 24) and medial frontal cortex (area 32). Decreased rCBF was observed in the amygdala region. These responses were interpreted with respect to their contribution to the multidimensional aspects of pain including fear avoidance, affect, sensation and motivation or motor initiation. It is suggested that future studies examine the precise roles of each particular region during the central processing of pain.     

Perceived self-efficacy and pain control: Opioid and nonopioid mechanisms.

In this experiment, we tested for opioid and nonopioid mechanisms of pain control through cognitive means and the relation of opioid involvement to perceived coping efficacy. Subjects were taught cognitive methods of pain control, were administered a placebo, or received no intervention. Their pain tolerance was then measured at periodic intervals after they were administered either a saline solution or naloxone, an opiate antagonist that blocks the effects of endogenous opiates. Training in cognitive control strengthened perceived self-efficacy both to withstand and to reduce pain; placebo medication enhanced perceived efficacy to withstand pain but not reductive efficacy; and neither form of perceived self-efficacy changed without any intervention. Regardless of condition, the stronger the perceived self-efficacy to withstand pain, the longer subjects endured mounting pain stimulation. The findings provide evidence that attenuation of the impact of pain stimulation through cognitive control is mediated by both opioid and nonopioid mechanisms. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Introduction to the special section on the structure of emotion.

This section is devoted to articles about the structure of affect, the patterned interrelations of moods and emotions. Structural features of affect, such as a bipolar pleasantness–unpleasantness dimension, a circumplex ordering, prototypical discrete emotions, and separable positive and negative emotion clusters, are discussed. It is proposed that positive and negative affect systems create the conditions for the co-occurrence of discrete positive emotions with each other and of discrete negative emotions with each other. The experience of affect tends to be felt along a bipolar pleasantness–unpleasantness dimension because pleasant emotions and unpleasant emotions tend not to be experienced together at intense levels. To move beyond current knowledge, future research in the area must more often use non-self-report measures, more sophisticated statistical and measurement methods, dynamic as well as static data, systematically varied response formats, and experimental manipulations. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Diurnal variation in rumination.

The present study investigated the daily fluctuation of ruminative thinking and its individual differences by using the experience sampling method. Participants recorded their thought contents and negative affect eight times a day for a week at semirandom intervals. High-trait ruminators showed high levels of self-focus, unpleasantness, and uncontrollability in their thoughts over the sampling course. These variables were interacted to predict the levels of concurrent negative affect: Self-focus was strongly associated with increased levels of negative affect when the thought was highly unpleasant and uncontrollable. A composite measure of rumination, including self-focus, unpleasantness, and uncontrollability, exhibited diurnal variation, which was assimilated by a quadratic function of time of day. However, there were differences in the estimated parameters of diurnal trajectories between high and low levels of depression, which indicated that individuals with higher levels of depression are more likely to engage in rumination in the evening, not in the morning, than those with lower levels of depression. These findings suggest that rumination in the evening would play an important role in the exacerbation and maintenance of depression. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Prevention of pain

Pain is a multistep process originating in the peripheral nervous system at the site of injury, transmitted by the peripheral nervous system, processed at several levels within the central nervous system, and finally perceived at the level of the cerebral cortex. Each of these steps in pain transmission is subject to intervention, with the possibility of reducing or blocking the nociceptive information to result in decreased pain. In general, therapeutic strategies that attempt to prevent the initiation or transmission of nociceptive information are more effective and safer than attempts to minimize pain after it occurs. Analgesic strategies based on knowledge of pain processes and results of controlled clinical trials should result in the prevention of pain in most patients, with fewer adverse effects than traditional analgesic therapy.     

Using reappraisal to regulate unpleasant emotional episodes: Goals and timing matter.

The hypothesis that cognitive reappraisal will have different effects on emotion as a function of regulatory goal and the timing with which reappraisals are enacted within an emotion episode was tested. Forty-one participants reappraised situations depicted in unpleasant pictures by imagining those situations getting worse (increase), staying the same (maintain), or getting better (decrease). Reappraisal instructions were delivered 2 s before (anticipatory) or 4 s after (online) picture onset. Measures of rated unpleasantness, expressive behavior (corrugator muscle activity), heart rate (HR), and electrodermal activity (EDA) were collected. Increase reappraisals produced higher rated unpleasantness, corrugator muscle activity, HR, and EDA relative to maintain reappraisals. For corrugator muscle activity and EDA, the effect of increase reappraisals was only apparent when enacted online. Decrease reappraisals produced lower rated unpleasantness relative to maintain reappraisals but had no effect on expressive behavior or autonomic physiology. The effect of decrease reappraisals did not depend on when reappraisal was enacted. These data underscore the importance of regulatory goals and the impact of regulatory timing as a moderator of emotion regulatory success within an emotion episode. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Temporal and intensity coding of pain in human cortex

Temporal and intensity coding of pain in human cortex. J. Neurophysiol. 80:3312-3320, 1998. We used a high-resolution functional magnetic resonance imaging (fMRI) technique in healthy right-handed volunteers to demonstrate cortical areas displaying changes of activity significantly related to the time profile of the perceived intensity of experimental somatic pain over the course of several minutes. Twenty-four subjects (ascorbic acid group) received a subcutaneous injection of a dilute ascorbic acid solution into the dorsum of one foot, inducing prolonged burning pain (peak pain intensity on a 0-100 scale: 48 +/- 3, mean +/- SE; duration: 11.9 +/- 0.8 min). fMRI data sets were continuously acquired for approximately 20 min, beginning 5 min before and lasting 15 min after the onset of stimulation, from two sagittal planes on the medial hemispheric wall contralateral to the stimulated site, including the cingulate cortex and the putative foot representation area of the primary somatosensory cortex (SI). Neural clusters whose fMRI signal time courses were positively or negatively correlated (P < 0.0005) with the individual pain intensity curve were identified by cross-correlation statistics in all 24 volunteers. The spatial extent of the identified clusters was linearly related (P < 0.0001) to peak pain intensity. Regional analyses showed that positively correlated clusters were present in the majority of subjects in SI, cingulate, motor, and premotor cortex. Negative correlations were found predominantly in medial parietal, perigenual cingulate, and medial prefrontal regions. To test whether these neural changes were due to aspecific arousal or emotional reactions, related either to anticipation or presence of pain, fMRI experiments were performed with the same protocol in two additional groups of volunteers, subjected either to subcutaneous saline injection (saline: n = 16), inducing mild short-lasting pain (peak pain intensity 23 +/- 4; duration 2.8 +/- 0.6 min) or to nonnoxious mechanical stimulation of the skin (controls: n = 16) at the same body site. Subjects did not know in advance which stimulus would occur. The spatial extent of neural clusters whose signal time courses were positively or negatively correlated with the mean pain intensity curve of subjects injected with ascorbic acid was significantly larger (P < 0.001) in the ascorbic acid group than both saline and controls, suggesting that the observed responses were specifically related to pain intensity and duration. These findings reveal distributed cortical systems, including parietal areas as well as cingulate and frontal regions, involved in dynamic encoding of pain intensity over time, a process of great biological and clinical relevance.     

Emotion-Modulated Performance and Activity in Left Dorsolateral Prefrontal Cortex.

Functional MRI (fMRI) was used to examine the relationship between processing of pleasant and unpleasant stimuli and activity in prefrontal cortex. Twenty volunteers identified the colors in which pleasant, neutral, and unpleasant words were printed. Pleasant words prompted more activity bilaterally in dorsolateral prefrontal cortex (DLPFC) than did unpleasant words. In addition, pleasant words prompted more activity in left than in right DLPFC. Response speed to pleasant words was correlated with DLPFC activity. These data directly link positive affect, enhanced performance, and prefrontal activity, providing some of the first fMRI evidence supporting models of emotional valence and frontal brain asymmetry based on electroencephalography (EEG). (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Anger management style and emotional reactivity to noxious stimuli among chronic pain patients and healthy controls: The role of endogenous opioids.

Objective: Previous work suggests that elevated trait anger-out exacerbates pain responses in part through endogenous opioid dysfunction. The authors examined whether this opioid dysfunction affects not only perceived pain intensity, but also emotional responses to being hurt. Design: 79 chronic low back pain (LBP) patients and 46 healthy controls received opioid blockade (8 mg naloxone i.v.) and placebo in randomized, counterbalanced order in separate sessions. During each session, participants sequentially experienced finger pressure pain and ischemic forearm pain tasks, with emotional state assessed at baseline and postpain. Main Outcome Measures: Blockade effects indexing opioid modulation of emotional reactivity were derived by subtracting placebo from blockade condition emotional reactivity. Results: Significant Participant Type × Anger-Out interactions on blockade effects indicated that in LBP participants but not in controls, greater anger-out was associated with deficient opioid modulation of anxiety, anger, and fear reactivity to noxious stimulation. Across participant types, greater anger-in was associated with impaired opioid modulation of anxiety and fear reactivity. Anger-in opioid effects were partially due to overlap with general negative affect. Conclusions: Opioid dysfunction associated with trait anger-out may affect not only perceived pain intensity, but also pain-related suffering in individuals with chronic pain conditions. Implications for understanding the health effects of anger management styles are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A longitudinal study of somesthetic perceptual disorders in an individual with a unilateral thalamic lesion

Several aspects of tactile, thermal and pain perception were evaluated in an individual (R.S.) with a hemorrhagic lesion centered in her left lateral thalamus. Over a 4-year period, psychophysical evaluations were undertaken every 6-8 months, and five magnetic resonance (MR) studies were conducted. Early tests (1991-1992) revealed large contralateral deficits in R.S.'s perception of touch, innocuous temperature, and mechanically evoked cutaneous pain--more so for the upper versus the lower extremity. R.S. showed a similar pattern for heat pain sensitivity, but a more modest deficit than for mechanically evoked pain. She showed a deficit for cold pain sensitivity on her foot, but not for her hand. Thresholds for all types of stimuli ipsilateral to the lesion were within a normative range. Late in 1993, R.S. demonstrated improvements in sensory capacity for touch and mechanically evoked pain contralaterally, although deficits were still evident. During the same period, heat pain sensitivity improved contralaterally, and strikingly, a permanent, ipsilateral hypersensitivity to heat pain developed in her hand. Throughout the entire testing period, R.S.'s ratings of perceived unpleasantness matched the patterns of perceived pain intensity. Thus, the discriminative and the affective dimensions of her pain would change in tandem. However, perceptible innocuous thermal stimuli evoked no affective response when applied contralaterally, despite being described as pleasant when presented ipsilaterally. Throughout the testing period, R.S. reported a persistent numbness on her right hemi-body. Only during a 3-month period in 1995 did she experience spontaneous pain, which was referred to her right foot. The only change in psychophysical performance related to her right foot was a transient but intense thermal allodynia several months prior to her spontaneous pain. The MR studies over this 4-year period showed changes in the extent of edema, gliosis and/or ischemia that could be related to perceptual changes. Thus, the conspicuous observations in this thalamic lesion case were: (i) differential effects upon the various pain modalities (mechanical, heat and cold); (ii) development of thermal allodynia without mechanical allodynia, including an ipsilateral effect; (iii) a deficit in positive affective responses to temperature; and (iv) the different time courses for changes in evoked somesthetic capacity versus spontaneous paresthesias and pathological pain.     

Effects of cigarette smoking on perception of thermal pain.

The effects of cigarette smoking on pain perception were evaluated in 18 healthy smokers. Thermal pain stimuli were used to assess pain detection threshold and tolerance and to collect subjective ratings of the intensity and unpleasantness of painful stimuli. After overnight abstinence, pain perception was evaluated before and after 3 experimental treatments. Participants smoked normal cigarettes, smoked denicotinized cigarettes, or remained abstinent. Smoking normal cigarettes produced relative increases in pain tolerance compared with abstinence. Smoking denicotinized cigarettes produced intermediate effects on tolerance not different from the other 2 treatments. Effects were not detected for pain threshold or subjective pain ratings. Results suggest that cigarette smoking can have antinociceptive effects, which may depend both on nicotine and on other factors associated with smoking. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Analgesic effects of posthypnotic suggestions and virtual reality distraction on thermal pain.

The individual and combined effects of posthypnotic suggestion (PHS) and virtual reality distraction (VRD) on experimentally induced thermal pain were examined using a 2 × 2, between-groups design. After receiving baseline thermal pain, each participant received hypnosis or no hypnosis, followed by VRD or no VRD during another pain stimulus. Consistent with the hypothesis that hypnosis and VRD work via different mechanisms, results show that posthypnotic analgesia was moderated by hypnotizability but VRD analgesia was not. The impact of PHSs for analgesia was specific to high hypnotizables, whereas VRD was effective independent of hypnotizability. Results also show a nonsignificant but predicted pattern for high hypnotizables: Audio hypnosis combined with VRD reduced worst pain 22% more and pain unpleasantness 25% more than did VRD alone. Theoretical and clinical implications are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Perceived self-efficacy in coping with cognitive stressors and opioid activation.

This experiment tested the hypothesis that perceived self-inefficacy in exercising control over cognitive stressors activates endogenous opioid systems. Subjects performed mathematical operations under conditions in which they could exercise full control over the cognitive task demands or in which the cognitive demands strained or exceeded their cognitive capabilities. Subjects with induced high perceived self-efficacy exhibited little stress, whereas those with induced low perceived self-efficacy experienced a high level of stress and autonomic arousal. Subjects were then administered either an inert saline solution or naloxone, an opiate antagonist that blocks the analgesic effects of endogenous opiates, whereupon their level of pain tolerance was measured. The self-efficacious nonstressed subjects gave no evidence of opioid activation. The self-inefficacious stressed subjects were able to withstand increasing amounts of pain stimulation under saline conditions. However, when endogenous opioid mechanisms that control pain were blocked by naloxone, the subjects were unable to bear much pain stimulation. This pattern of changes suggests that the stress-induced analgesia found under the saline condition was mediated by endogenous opioid mechanisms and counteracted by the opiate antagonist. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The effects of hypnotic susceptibility, suggestions for analgesia, and the utilization of cognitive strategies on the reduction of pain.

96 undergraduates were stratified in terms of hypnotic susceptibility (high, medium, and low) on the Harvard Group Scale of Hypnotic Susceptibility, Form A. Ss next had 1 arm immersed in ice water for a 60-sec pretest and, afterward, were assigned to 1 of 4 treatments: (a) hypnosis plus analgesia suggestion, (b) hypnosis alone, (c) suggestion alone, or (d) no hypnosis—no suggestion. Ss were retested in ice water and then interviewed about their experiences during the retest. High susceptibles reported the use of more cognitive strategies during the retest and showed greater pretest-to retest pain magnitude reductions than did low susceptibles. Similar effects occurred for Ss given, as opposed to not given, a suggestion. The hypnosis variable, however, failed to affect either strategy use or pain magnitude. Strategy use facilitated pain reduction only for Ss who did not worry about and did not exaggerate the unpleasantness of the situation (i.e., noncatastrophizers). The few Ss who showed dramatic pretest-to-retest reductions in pain magnitude (50% reduction or more) were all high-susceptible noncatastrophizers who used one or more cognitive strategies. (37 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Ser-311-Cys polymorphism of the dopamine D2 receptor gene and schizophrenia--an analysis of schizophrenic patients in Fukuoka

Functional brain imaging studies have indicated that several cortical and subcortical areas active during actual motor performance are also active during imagination or mental rehearsal of movements. Recent evidence shows that the primary motor cortex may also be involved in motor imagery. Using whole-scalp magnetoencephalography, we monitored spontaneous and evoked activity of the somatomotor cortex after right median nerve stimuli in seven healthy right-handed subjects while they kinesthetically imagined or actually executed continuous finger movements. Manipulatory finger movements abolished the poststimulus 20-Hz activity of the motor cortex and markedly affected the somatosensory evoked response. Imagination of manipulatory finger movements attenuated the 20-Hz activity by 27% with respect to the rest level but had no effect on the somatosensory response. Slight constant stretching of the fingers suppressed the 20-Hz activity less than motor imagery. The smallest possible, kinesthetically just perceivable finger movements resulted in slightly stronger attenuation of 20-Hz activity than motor imagery did. The effects were observed in both hemispheres but predominantly contralateral to the performing hand. The attempt to execute manipulatory finger movements under experimentally induced ischemia causing paralysis of the hand also strongly suppressed 20-Hz activity but did not affect the somatosensory evoked response. The results indicate that the primary motor cortex is involved in motor imagery. Both imaginative and executive motor tasks appear to utilize the cortical circuitry generating the somatomotor 20-Hz signal.     

Cognitive correlates of emotional traits: Perceptions of self and others.

Two studies examined how individuals' perceptions of self and others are associated with different emotional traits. Study 1 (N = 386) used structural equation modeling of questionnaire data to examine the relations between emotional traits (i.e., affect intensity, affect variability, and trait pleasant and unpleasant affect) and self- and other-perceptions (i.e., self-instability, self-esteem, other-instability, and perceived treatment by others). Study 2 (N = 99) used path analyses of data collected using an event sampling method in which online measures of emotional experiences (i.e., intensity, frequency, and variability of pleasant and unpleasant affect) as well as perceptions of self and others (i.e., self-instability, self-esteem, other-instability, perceived treatment by others) were collected. The strongest and most consistent finding was that affect variability was associated with both self- and other-instability. The results linking affect intensity with self- and other-instability were limited to negative intensity. There was also evidence of pleasant affect being associated with both self-esteem and perceived treatment by others, and unpleasant affect being associated with self-esteem and other-instability. (PsycINFO Database Record (c) 2011 APA, all rights reserved)