Perceived controllability modulates the neural response to pain

The response to painful stimulation depends not only on peripheral nociceptive input but also on the cognitive and affective context in which pain occurs. One contextual variable that affects the neural and behavioral response to nociceptive stimulation is the degree to which pain is perceived to be controllable. Previous studies indicate that perceived controllability affects pain tolerance, learning and motivation, and the ability to cope with intractable pain, suggesting that it has profound effects on neural pain processing. To date, however, no neuroimaging studies have assessed these effects. We manipulated the subjects' belief that they had control over a nociceptive stimulus, while the stimulus itself was held constant. Using functional magnetic resonance imaging, we found that pain that was perceived to be controllable resulted in attenuated activation in the three neural areas most consistently linked with pain processing: the anterior cingulate, insular, and secondary somatosensory cortices. This suggests that activation at these sites is modulated by cognitive variables, such as perceived controllability, and that pain imaging studies may therefore overestimate the degree to which these responses are stimulus driven and generalizable across cognitive contexts. [References: 28]

Individual differences in the effects of perceived controllability on pain perception: critical role of the prefrontal cortex

The degree to which perceived controllability alters the way a stressor is experienced varies greatly among individuals. We used functional magnetic resonance imaging to examine the neural activation associated with individual differences in the impact of perceived controllability on self-reported pain perception. Subjects with greater activation in response to uncontrollable (UC) rather than controllable (C) pain in the pregenual anterior cingulate cortex (pACC), periaqueductal gray (PAG), and posterior insula/SII reported higher levels of pain during the UC versus C conditions. Conversely, subjects with greater activation in the ventral lateral prefrontal cortex (VLPFC) in anticipation of pain in the UC versus C conditions reported less pain in response to UC versus C pain. Activation in the VLPFC was significantly correlated with the acceptance and denial subscales of the COPE inventory [Carver, C. S., Scheier, M. F., & Weintraub, J. K. Assessing coping strategies: A theoretically based approach. Journal of Personality and Social Psychology, 56, 267–283, 1989], supporting the interpretation that this anticipatory activation was associated with an attempt to cope with the emotional impact of uncontrollable pain. A regression model containing the two prefrontal clusters (VLPFC and pACC) predicted 64% of the variance in pain rating difference, with activation in the two additional regions (PAG and insula/SII) predicting almost no additional variance. In addition to supporting the conclusion that the impact of perceived controllability on pain perception varies highly between individuals, these findings suggest that these effects are primarily top-down, driven by processes in regions of the prefrontal cortex previously associated with cognitive modulation of pain and emotion regulation.

Communicating information about medication side effects: effects on satisfaction, perceived risk to health, and intention to comply

Previous research has shown that people's evaluations of explanations about medication and their intention to comply with the prescription are detrimentally affected by the inclusion of information about adverse side effects of the medication. The present study (Experiment 1) examined which particular aspects of information about side effects (their number, likelihood of occurrence, or severity) are likely to have the greatest effect on people's satisfaction, perception of risk, and intention to comply, as well as how the information about side effects interacts with information about the severity of the illness for which the medication was prescribed. Across all measures, it was found that manipulations of side effect severity had the greatest impact on people's judgements, followed by manipulations of side effect likelihood and then number. Experiments 2 and 3 examined how the severity of the diagnosed illness and information about negative side effects interact with two other factors suggested by Social Cognition models of health behaviour to affect people's intention to comply: namely, perceived benefit of taking the prescribed drug, and the perceived level of control over preventing or alleviating the side effects. It was found that providing people with a statement about the positive benefit of taking the medication had relatively little effect on judgements, whereas informing them about how to reduce the chances of experiencing the side effects had an overall beneficial effect on ratings.

Young adults and the 5 a day campaign: perceived benefits and barriers of eating more fruits and vegetables

Although consuming adequate amounts of fruits and vegetables reduces the risk of developing chronic diseases, it is widely recognized that young adults’ intakes are currently well below the Department of Health’s recommended five portions a day, with men consuming even less than women. One approach in the UK has been to introduce health campaigns such as the 5 A DAY programme; however, little is currently known about how well their messages are understood amongst young adults. This study examined current knowledge of the 5 A DAY message in young adults, as well as the perceived benefits and remaining barriers towards consuming more fruits and vegetables. In total, four focus groups were conducted using male (n = 22) and female (n = 18) students at the University of Reading. Content analysis revealed that while participants were aware of the 5 A DAY recommendation, there was widespread confusion regarding the detail. In addition, men were less accepting of the message than women, reporting greater disbelief and a lack of motivation to increase intake. Finally, a range of barriers was reported by participants of both genders, despite the perceived beneficial effects for health and appearance. The results illustrate a considerable gap between awareness and knowledge of the 5 A DAY message, and underscore the challenge that changing behaviour in young adults represents. As well as stepping up education- and skill-based health campaigns, more targeted gender specific interventions will be needed to achieve sustained increases in fruit and vegetable intake.

Differences in perceived risks and benefits of herbal, over-the-counter conventional, and prescribed conventional, medicines, and the implications of this for the safe and effective use of herbal products

Objectives: To investigate people's views about the efficacy and specific risks of herbal, over-the-counter (OTC) conventional, and prescribed conventional medicines, and their likelihood of taking a second (herbal or OTC conventional) product in addition to a prescribed medicine. Methods: Experiment 1 (1 factor within-participant design); Experiment 2 (1 factor between-participant design). Convenience samples of general population were given a hypothetical scenario and required to make a number of judgements. Results: People believed herbal remedies to be less effective, but less risky than OTC and prescribed conventional medicines. Herbal medicines were not seen as being safer simply because of their easier availability. Participants indicated that they would be more likely to take a herbal medicine than a conventional OTC medicine in addition to a prescribed medicine, and less likely to consult their doctor in advance. Conclusion: People believe that herbal medicines are natural and relatively safe and can be used with less caution. People need to be given clear information about the risks and benefits of herbal medicines if they are to use such products safety and effectively. (c) 2006 Elsevier Ltd. All rights reserved.

Perceived spatial displacement of motion-defined contours in peripheral vision

The perceived displacement of motion-defined contours in peripheral vision was examined in four experiments. In Experiment 1, in line with Ramachandran and Anstis' finding [Ramachandran, V. S., & Anstis, S. M. (1990). Illusory displacement of equiluminous kinetic edges. Perception, 19, 611-616], the border between a field of drifting dots and a static dot pattern was apparently displaced in the same direction as the movement of the dots. When a uniform dark area was substituted for the static dots, a similar displacement was found, but this was smaller and statistically insignificant. In Experiment 2, the border between two fields of dots moving in opposite directions was displaced in the direction of motion of the dots in the more eccentric field, so that the location of a boundary defined by a diverging pattern is perceived as more eccentric, and that defined by a converging as less eccentric. Two explanations for this effect (that the displacement reflects a greater weight given to the more eccentric motion, or that the region containing stronger centripetal motion components expands perceptually into that containing centrifugal motion) were tested in Experiment 3, by varying the velocity of the more eccentric region. The results favoured the explanation based on the expansion of an area in centripetal motion. Experiment 4 showed that the difference in perceived location was unlikely to be due to differences in the discriminability of contours in diverging and converging pattems, and confirmed that this effect is due to a difference between centripetal and centrifugal motion rather than motion components in other directions. Our result provides new evidence for a bias towards centripetal motion in human vision, and suggests that the direction of motion-induced displacement of edges is not always in the direction of an adjacent moving pattern. (C) 2008 Elsevier Ltd. All rights reserved.

The influence of changing nicotine to tar ratios on human puffing behaviour and perceived sensory response

Rationale. Smokers modify their smoking behaviour when switching from their usual product to higher or lower tar and nicotine-yield cigarettes. Objective. The aims of the current study were to assess the influence of varying nicotine yields at constant tar yield on human puffing measures, nicotine deliveries under human smoking conditions and the sensory response to mainstream cigarette smoke. These assessments would allow an evaluation of the degree of compensation and the various possible causes of changes, if any. Methods. The participants were 13 regular smokers of commercial or hand-rolled cigarettes. They were tested with four cigarettes, which exhibited a wide range of nicotine to 'tar' ratios at a relatively constant 'tar' yield. Their smoking behaviour was monitored by placing the test cigarettes into an orifice-type holder/flowmeter attached to a custom-built smoker behaviour analyser. In addition, a comprehensive sensory evaluation of the products was carried out. Results. The differences in the nicotine to tar ratios of the samples did not significantly influence the puffing behaviour patterns, i.e. puff number and interval, total and average puff volume, integrated pressure and puff duration. Additionally the pre- to post-exhaled CO boosts were not significantly influenced by the experimental samples used in the study. However, the nicotine yields obtained by the smokers were significantly influenced by the machine-smoked nicotine yields or the nicotine to tar ratios of the samples. The machine-smoked nicotine yields were highly correlated with the nicotine yields obtained under human smoking conditions. For the sensory evaluation, there was only a significant difference between the samples in the intensity of the impact. Conclusion. These observations imply that these puffing variables are not controlled by the nicotine yield of the cigarette.

Young people with intellectual disabilities attending mainstream and segregated schooling: perceived stigma, social comparison and future aspirations

Mainstream schooling is a key policy in the promotion of social inclusion of young people with learning disabilities. Yet there is limited evidence about the school experience of young people about to leave mainstream as compared with segregated education, and how it impacts on their relative view of self and future aspirations. Sixty young people with mild to moderate intellectual disabilities in their final year of secondary school participated in this study. Twenty-eight individuals came from mainstream schools and 32 attended segregated school. They completed a series of self-report measures on perceptions of stigma, social comparison to a more disabled and non-disabled peer and the likelihood involved in attaining their future goals. The majority of participants from both groups reported experiencing stigmatized treatment in the local area where they lived. The mainstream group reported significant additional stigma at school. In terms of social comparisons, both groups compared themselves positively with a more disabled peer and with a non-disabled peer. While the mainstream pupils had more ambitious work-related aspirations, both groups felt it equally likely that they would attain their future goals. Although the participants from segregated schools came from significantly more deprived areas and had lower scores on tests of cognitive functioning, neither of these factors appeared to have an impact on their experience of stigma, social comparisons or future aspirations. Irrespective of schooling environment, the young people appeared to be able to cope with the threats to their identities and retained a sense of optimism about their future. Nevertheless, negative treatment reported by the children was a serious source of concern and there is a need for schools to promote the emotional well-being of pupils with intellectual disabilities.

Measuring perceived brand luxury: an evaluation of the BLI scale

This paper investigates the psychometric properties of Vigneron and Johnson's Brand Luxury Index scale. The authors developed the scale using data collected from a student sample in Australia. To validate the scale, the study reported in this paper uses data collected from Taiwanese luxury consumers. The scale was initially subjected to reliability analysis yielding low α values for two of its five proposed dimensions. Exploratory and confirmatory factors analyses were subsequently performed to examine the dimensionality of brand luxury. Discriminant and convergent validity tests highlight the need for further research into the dimensionality of the construct. Although the scale represents a good initial contribution to understanding brand luxury, in view of consumers' emerging shopping patterns, further investigation is warranted to establish the psychometric properties of the scale and its equivalence across cultures.

Vision of the body and the differentiation of perceived body side in touch

Although tactile representations of the two body sides are initially segregated into opposite hemispheres of the brain, behavioural interactions between body sides exist and can be revealed under conditions of tactile double simultaneous stimulation (DSS) at the hands. Here we examined to what extent vision can affect body side segregation in touch. To this aim, we changed hand-related visual input while participants performed a go/no-go task to detect a tactile stimulus delivered to one target finger (e.g., right index), stimulated alone or with a concurrent non-target finger either on the same hand (e.g., right middle finger) or on the other hand (e.g., left index finger = homologous; left middle finger = non-homologous). Across experiments, the two hands were visible or occluded from view (Experiment 1), images of the two hands were either merged using a morphing technique (Experiment 2), or were shown in a compatible vs incompatible position with respect to the actual posture (Experiment 3). Overall, the results showed reliable interference effects of DSS, as compared to target-only stimulation. This interference varied as a function of which non-target finger was stimulated, and emerged both within and between hands. These results imply that the competition between tactile events is not clearly segregated across body sides. Crucially, non-informative vision of the hand affected overall tactile performance only when a visual/proprioceptive conflict was present, while neither congruent nor morphed hand vision affected tactile DSS interference. This suggests that DSS operates at a tactile processing stage in which interactions between body sides can occur regardless of the available visual input from the body.

Perceived helplessness is associated with individual differences in the central motor output system

Learned helplessness is a maladaptive response to uncontrollable stress characterized by impaired motor escape responses, reduced motivation and learning deficits. There are important individual differences in the likelihood of becoming helpless following exposure to uncontrollable stress but little is known about the neural mechanisms underlying these individual differences. Here we used structural MRI to measure gray and white matter in individuals with chronic pain, a population at high risk for helplessness due to prolonged exposure to a poorly controlled stressor (pain). Given that self-reported helplessness is predictive of treatment outcomes in chronic pain, understanding such differences might provide valuable clinical insight. We found that the magnitude of self-reported helplessness correlated with cortical thickness in the supplementary motor area (SMA) and midcingulate cortex, regions implicated in cognitive aspects of motor behavior. We then examined the white matter connectivity of these regions and found that fractional anisotropy of connected white matter tracts along the corticospinal tract was associated with helplessness and mediated the relationship between SMA cortical thickness and helplessness. These data provide novel evidence that links individual differences in the motor output pathway with perceived helplessness over a chronic and poorly controlled stressor.