Pain and pain perception

Pain is both sensual perception and sense of touch, and it leads to emotional change of health, which has an effect back to a pain perception. Experience of pain is modified by intern and extern influences, and it can appear very multiformly in the chronicity. A part of these factors are described.     

Prism adaptation while tracking and saccading

It is known that positional discordance between the spatial senses is a sufficient condition for prism adaptation of registered eye-in-head position. In this experiment adaptation was carried out under conditions in which Ss viewed their feet while making extensive tracking or saccading movements of their eyes. It has been claimed that tracking makes available less precise position information than saccading (Festinger and Canon 1965), but it is found that both modes are equally successful in causing this form of adaptation. It is concluded that either tracking and saccading yield equally valid estimates of eye-in-head position, or that the normal straight ahead position of the eye is a unique reference position.     

Negative affect and sensitization to pain

Pain usually has a strong negative affective component, which is believed to modulate pain perception. After reviewing theories on the link between negative affect and pain, mechanisms are discussed by which negative affect may either increase or inhibit pain. Possible pain-inhibiting mechanisms are endogenous opioid release, blood pressure reactivity, and distraction of attention; possible pain-increasing mechanisms are autonomic and muscular reactivity, misattribution of arousal, hypervigilance to pain, worrying, and avoidance behavior. It is emphasized that each of these mechanisms can be very adaptive in acute pain situations to prevent injury and promote recovery. In chronic pain, however, ongoing physiological arousal and hypervigilance to pain, induced or magnified by negative affect, may cause sensitization to pain. Furthermore, worrying about pain and avoidance of pain-inducing activities may increase negative affect, ypervigilance, and functional disability. It is argued that, in the long run, pain-related negative affect has sensitizing and disabling effects.     

Catastrophizing and pain perception in sport participants

Abstract

Two studies were conducted to examine the relation between catastrophizing and pain in sport participants. Study 1 compared the factor structure of the Pain Catastrophizing Scale (PCS; Sullivan et al., 1995) in a sample of 97 individuals who reported engaging in regular sporting activity and 140 sedentary individuals. Confirmatory factor analysis revealed that, in both sport and sedentary samples, a three factor solution, comprising rumination, magnification, and helplessness provided the best fit to the data. Study 2 examined differences in pain perception in 54 (28 women, 26 men) varsity athletes and 54 (27 women, 27 men) sedentary controls who participated in an experimental pain procedure. Participants completed the PCS prior to immersing one arm in ice water for one minute. Athletes reported less pain than sedentary individuals, and men reported less pain than women. For both athlete and sedentary groups, catastrophizing was a significant predictor of pain experience. Regression analyses revealed that although catastrophizing accounted for differences in pain perception between men and women     

Mechanisms of long-term dark adaptation

It has previously been suggested that long-term dark adaptation is controlled by bleaching signals that regulate the activity of an allosteric, positively cooperative protein (Stabell et al., 1986a, b). Recent biochemical evidence strongly supports this assumption, indicating that the primary regulator of the light-sensitive channels in the plasma membrane of the outer segments of the photoreceptors is a homo-oligomeric, allosteric, positively cooperative protein. In this report, we discuss the possibility that signals from bleached photopigments may control the dark-adaptation process through the allosteric protein of the plasma membrane. It is suggested that the concentrations of the bleached photopigment and of the allosteric effector are reciprocal quantities.     

婴儿的痛觉

婴儿痛觉对婴儿的生长发育有重要意义, 已经日益引发研究者的兴趣。痛觉本质上是一种不愉悦的感官和情绪体验, 是通过早年与伤害有关的经历习得的。在心理学角度, 在介绍婴儿痛觉概念、神经生理机制、评估工具的基础上, 系统梳理痛觉对婴儿生长发育的影响及其影响因素十分必要。后续研究需继续完善婴儿痛觉的测量方法, 考察疼痛反应在不同文化和不同群体间的差异。     

Neurocognitive aspects of pain perception

The perception of pain is sensitive to various mental processes such as the feelings and beliefs that someone has about pain. It is therefore not exclusively driven by the noxious input. Attentional modulation involving the descending pain modulatory system has been examined extensively in neuroimaging studies. However, the investigation of neural mechanisms underlying more complex cognitive modulation is an emerging field in pain research. Recent findings indicate an engagement of the ventrolateral prefrontal cortex during more complex modulation, leading to a change or reappraisal of the emotional significance of pain. Taking placebo-induced analgesia as an example, we discuss the contribution of attention, expectation and reappraisal as three basic mechanisms that are important for the cognitive modulation of pain.     

Beautiful faces in pain: Biases and accuracy in the perception of pain

Abstract

The impact of appearance-based information on judgments about the psychological functioning of pain patients was investigated. Video-tapes of low back pain patients experiencing pain were used as stimulus materials. Subjects viewed silent video clips and photographs of the patients' faces and made judgments about the functioning of these patients. These judgments were affected both by patient physical attractiveness and gender. Physically attractive patients and male patients were judged to be functioning better than physically unattractive and female patients. The judgments were reasonably described as biased because the perceived differences about patients varying in attractiveness and sex were not associated with measures of actual patient functioning.     

Cognitive mediators of pain perception and tolerance

A social learning model of pain perception and tolerance was evaluated. Responses to cold-pressor pain were examined in 4 groups of 20 Ss each. One group was given instruction in cognitive coping strategies, the 2nd was given a monetary incentive contingent on tolerance time, the 3rd was given both cognitive training and monetary reinforcement, and a no-treatment control group was given neither. Incentive and coping instructions significantly increased tolerance but did not alter pain perception. A path analysis indicated that pain tolerance was affected by self-efficacy, which in turn was predicted by pain expectancy and the provision of incentives. Incentive also had an impact on tolerance that was independent of self-efficacy. Pain perception was strongly affected by pain expectancy, but was unrelated to self-efficacy.     

Changes in motion perception following oculomotor smooth pursuit adaptation

The hypothesis that oculomotor smooth pursuit (SP) adaptation is accompanied by alterations in velocity perception was tested by assessing coherence thresholds, using random-dot kinematograms before and after the adaptation paradigm. The results showed that the sensitivity to coherent motion at 10 deg/sec (the initial target velocity during adaptation) was reduced after the SP adaptation, ending up at a level that was between those normally observed for velocities of 10 and 20 deg/sec. This is consistent with an overestimation of the velocity of the coherent motion and suggests that SP adaptation alters not only the oculomotor output, but also the perception of target velocity.     

疼痛恐惧的形成及其对疼痛知觉的影响

脑岛、杏仁核是疼痛恐惧形成的重要神经网络中心。疼痛恐惧增强了慢性疼痛患者的疼痛知觉体验, 进而加剧抑郁、焦虑情绪和功能损伤程度。脑岛、杏仁核、前额皮层和前扣带回是疼痛恐惧影响疼痛知觉的重要神经基础。通过认知方法干预疼痛恐惧可以改善患者的抑郁、焦虑情绪, 减少功能损伤。未来研究应拓展疼痛恐惧的测量工具, 采用功能磁共振成像技术进一步揭示疼痛恐惧影响慢性疼痛患者疼痛知觉的神经机制。     

Rapid adaptation of the vestibulo-ocular reflex and induced self-motion perception

When a rigid object moves toward the eye, it is usually perceived as being rigid. However, in the case of motion away from the eye, the motion and structure of the object are perceived nonveridically, with the percept tending to reflect the nonrigid transformations that are present in the retinal image. This difference in response to motion to and from the observer was quantified in an experiment using wire-frame computer-generated boxes which moved toward and away from the eye. Two theoretical systems are developed by which uniform three-dimensional velocity can be recovered from an expansion pattern of nonuniform velocity vectors. It is proposed that the human visual system uses two similar systems for processing motion in depth. The mechanism used for motion away from the eye produces perceptual errors because it is not suited to objects with a depth component.     

Target distance and adaptation in distance perception in the constancy of visual direction

Hay and Sawyer recently demonstrated that the constancy of visual direction (CVD) also operates for near targets. A luminous spot in the dark, 40 cm from the eyes, was perceived as stationary when S nodded his head. This implies that CVD takes target distance, as well as head rotation, into account as a stationary environment is perceived during head movements. Distance is a variable in CVD because, during a turning or nodding of the head, the eyes become displaced relative to the main target direction, the line between the target and the rotation axis of the head. This displacement of the eyes during head rotation causes an additional change in the target direction, i.e., a total angular change greater than the angle of the head rotation. The extent of this additional angular displacement is greater the nearer the target. We demonstrated that the natural combination of accommodation and convergence can supply the information needed by the nervous system to compensate for this additional target displacement. We also found that wearing glasses that alter the relation between these oculomotor adjustments and target distance produces an adaptation in CVD. An adaptation period of 1.5 h produced a large adaptation effect. This effect was not entirely accounted for by an adaptation in distance perception. Measurements of the alteration between oculomotor cues and registered distance with two kinds of tests for distance perception yielded effects significantly smaller than the effect measured with the CVD test. We concluded that the wearing of the glasses had also produced an adaptation within CVD.