People in pain make poorer decisions

The Interplay Between Experimental Heat Pain and Noninvasive Stimulation of the Medial Prefrontal Cortex on Reinforcement Learning With Manipulated Outcome Contingencies

Pain negatively affects several cognitive abilities, but knowledge about its effect on reinforcement learning (RL) is limited. During RL, instrumental choices can be influenced by heuristic tendencies to approach rewards or inhibit actions when facing potentially aversive events, introducing "Pavlovian bias" in behavior. Recent studies suggest that compromised outcome controllability enhances Pavlovian bias, a phenomenon that may be linked to suboptimal decision-making in learned helplessness (LH). Since LH is common in chronic pain syndromes, this study sought to establish a link between experimental heat pain (EHP), disrupted reward/loss contingencies, and RL performance in healthy adults. In addition, we investigated if intermittent theta burst stimulation (iTBS) above the medial prefrontal/dorsal anterior cingulate cortex (mPFC/dACC) alleviates the deleterious effects of EHP on choice behavior. In a preregistered, 2 × 2 between-group, double-blind study (N = 100), healthy adult participants underwent three blocks of an orthogonalized Go/NoGo task with two interleaved bouts of active or sham iTBS, and either EHP or warm skin stimulation combined with manipulated response-outcome contingency during the task. Although EHP did not impact response accuracy, it invigorated actions for rewards, reflecting enhanced Pavlovian bias. Whereas two bouts of iTBS attenuated Pavlovian tendencies, this effect was counteracted by EHP, indicating antagonistic effects of pain and iTBS-modulated mPFC activity on Pavlovian-instrumental interactions. Surprisingly, EHP and iTBS exerted largely similar effects on other latent parameters of RL (go-bias, learning rate, and exploration) in a manner that resembled LH. These findings shed light on the role of experimental pain and mPFC/dACC activity in LH-like choice behavior.

Impact of Experimentally Induced Pain on Logical Reasoning and Underlying Attention-Related Psychophysiological Mechanisms

BACKGROUND

Pain is known to negatively impact attention, but its influence on more complex cognitive abilities, such as logical reasoning, remains inconsistent. This may be due to compensatory mechanisms (e.g., investing additional resources), which might not be detectable at the behavioral level but can be observed through psychophysiological measures. In this study, we investigated whether experimentally induced pain affects logical reasoning and underlying attentional mechanisms, using both behavioral and electroencephalographic (EEG) measures.

METHODS

A total of 98 female participants were divided into a pain-free control group (N = 47) and a pain group (N = 51). Both groups completed the Advanced Progressive Matrices (APM) task, with EEG recordings capturing task-related power (TRP) changes in the upper alpha frequency band (10-12 Hz). We used a mixed design where all participants completed half of the APM task in a pain-free state (control condition); the second half was completed under pain induction by the pain group but not the pain-free group (experimental condition).

RESULTS

Logical reasoning performance, as measured by APM scores and response times, declined during the experimental condition, compared to the control condition for both groups, indicating that the second part of the APM was more difficult than the first part. However, no significant differences were found between the pain and pain-free groups, suggesting that pain did not impair cognitive performance at the behavioral level. In contrast, EEG measures revealed significant differences in upper alpha band power, particularly at fronto-central sites. In the pain group, the decrease in TRP during the experimental condition was significantly smaller compared to both the control condition and the pain-free group.

CONCLUSIONS

Pain did not impair task performance at the behavioral level but reduced attentional resources, as reflected by changes in upper alpha band activity. This underscores the importance of incorporating more sensitive psychophysiological measures alongside behavioral measures to better understand the impact of pain on cognitive processes.

Hits and Misses: Digital Contact Tracing in a Pandemic

Traditional contact tracing is one of the most powerful weapons people have in the battle against a pandemic, especially when vaccines do not yet exist or do not afford complete protection from infection. But the effectiveness of contact tracing hinges on its ability to find infected people quickly and obtain accurate information from them. Therefore, contact tracing inherits the challenges associated with the fallibilities of memory. Against this backdrop, digital contact tracing is the "dream scenario"-an unobtrusive, vigilant, and accurate recorder of danger that should outperform manual contact tracing on every dimension. There is reason to celebrate the success of digital contact tracing. Indeed, epidemiologists report that digital contact tracing probably reduced the incidence of COVID-19 cases by at least 25% in many countries, a feat that would have been hard to match with its manual counterpart. Yet there is also reason to speculate that digital contact tracing delivered on only a fraction of its potential because it almost completely ignored the relevant psychological science. We discuss the strengths and weaknesses of digital contact tracing, its hits and misses in the COVID-19 pandemic, and its need to be integrated with the science of human behavior.

Altered social decision making in patients with chronic pain

BACKGROUND

Chronic pain affects up to 20% of the population, impairs quality of life and reduces social participation. Previous research reported that pain-related perceived injustice covaries with these negative consequences. The current study probed whether chronic pain patients responded more strongly to disadvantageous social inequity than healthy individuals.

METHODS

We administered the Ultimatum Game, a neuroeconomic social exchange game, where a sum of money is split between two players to a large sample of patients with chronic pain disorder with somatic and psychological factors (n = 102) and healthy controls (n = 101). Anonymised, and in truth experimentally controlled, co-players proposed a split, and our participants either accepted or rejected these offers.

RESULTS

Chronic pain patients were hypersensitive to disadvantageous inequity and punished their co-players for proposed unequal splits more often than healthy controls. Furthermore, this systematic shift in social decision making was independent of patients' performance on tests of executive functions and risk-sensitive (non-social) decision making .

CONCLUSIONS

Our findings indicate that chronic pain is associated with anomalies in social decision making (compared to healthy controls) and hypersensitivity to social inequity that is likely to negatively impact social partaking and thereby the quality of life.

How does experimentally induced pain affect creative ideation and underlying attention-related psychophysiological mechanisms?

While the adverse effect of chronic pain on attention and more complex cognitive abilities is well documented, the findings for experimentally induced pain are inconsistent. These inconsistencies could be attributable to sufficient attentional resources and/or compensatory mechanisms in individuals experiencing experimentally induced pain that are not observable at the behavioral level but could be revealed by psychophysiological measures such as the electroencephalography (EEG). With the current study, we aimed to investigate whether experimentally induced pain affects creative ideation in an adaptation of the Alternate Uses Task (AUT). Performance in the AUT was compared between 39 females in a pain group and 37 females in a pain-free group. While solving the task, EEG was recorded to measure the degree of internally directed attention assessed by means of task-related power (TRP) changes in the upper alpha-frequency band. The results revealed that the pain group and the pain-free group did not differ in AUT performance at the behavioral level. However, TRP increases in the upper alpha band at right (vs. left) temporal, parietal, and occipital electrode sites were significantly more pronounced in the pain group compared to the pain-free group. These results indicate that individuals in the pain group allocated more attention to internal mental processes during creative ideation than individuals in the pain-free group. The necessary inhibition of pain might have caused this additional activation so that the pain group performed similarly well on the behavioral level as the pain-free group.

The impact of chronic pain on creative ideation: An examination of the underlying attention-related psychophysiological mechanisms

Background

Attentional deficits in patients with chronic pain are common and well studied. Yet, few studies have examined the effects of chronic pain on more complex cognitive abilities that rely on well‐functioning attentional systems. With the current study, we aimed to investigate whether the impact of chronic pain on attention affects creative ideation as measured with an adaptation of the alternate uses task (AUT).

Methods

Performance in the AUT was compared between 33 patients suffering from chronic pain and 33 healthy matched controls. While solving the task, EEG was recorded to measure the degree of internally directed attention assessed by means of task‐related power (TRP) changes.

Results

The results revealed that patients with chronic pain generated less creative ideas than healthy controls. This lack of performance was accompanied by lower event‐related synchronization (ERS), especially in right parietal sites. Furthermore, these ERS differences explained one‐third of the inter‐group variance in AUT performance.

Conclusions

These results suggest that performance decrements in creative ideation in patients with chronic pain may be at least partly attributable to attentional impairments associated with chronic pain.

Significance

Chronic pain negatively affects attention and more complex cognitive abilities. However, the underlying psychophysiological mechanisms and the role of attention as a source of these impairments in more complex abilities are poorly understood. By analyzing task‐related power changes in the EEG, the role of internal attention in creative ideation could be determined, revealing the functional relationship between chronic pain, attention, and a more complex cognitive ability.

Ongoing pain facilitates emotional decision-making behaviors

Emotion toward anticipated and actual outcomes acts as a vital signal on emotional decision-making, and the Iowa Gambling Task (IGT) can mimic this decision-making process. Pain can impair emotional decision-making behaviors because it captures attention and distracts from the task at hand. Alternatively, pain may facilitate emotional decision-making behaviors by prompting alertness and mobilizing cognitive resources to maximize rewards. The present study investigated the influence of ongoing pain on emotional decision-making behaviors using the IGT. Our study recruited two groups of participants and applied capsaicin (pain group) or control cream (control group) to their forearms. We then compared performances and selections between the pain and control groups. The results revealed that participants successfully learned the required adaptive selection strategy as the task progressed. The study observed a tendency toward optimal choices for both groups under the condition of frequent–small losses. However, we observed a disadvantageous preference for the control group, but not the pain group, when faced with choices with infrequent but large losses. The study implies that a distressing pain experience motivates individuals to adjust goal-directed behaviors to maximize their rewards in a task. Thus, the finding suggests that ongoing pain facilitates emotional decision-making behaviors.

The disruptive effects of pain on the early allocation of attentional resources: An attentional blink study

BACKGROUND

Recent evidence suggests that pain dampens attentional processes. However, much of this work has been based on higher-order attentional tasks that involve only spatial attention. Other aspects of the process through which pain engages and holds attention are relatively understudied, in particular, temporal attention. The present set of studies explored how naturally occurring pain (i.e. acute headache) and pain-valenced stimuli affect the ability to recall the second of two targets presented in rapid succession.

METHODS

Across both experiments participants were required to indicate the presence of a predefined probe (T2) and, in the dual task, identify a target (T1). The probe (T2) was placed in three different temporal proximities (ranging from 70 to 1000 ms) following presentation of the target (T1). In Experiment 1, 36 participants completed a task that comprised a rapid stream of letters. Experiment 2 manipulated the threat value, and the complexity, of the stimuli by replacing letters with words. In the dual task condition, T1 was a word from one of four valence categories (neutral, positive, negative, pain).

RESULTS

Being in acute pain reduced the accuracy of identification. This reduction in performance occurred regardless of the temporal positioning of the probe, consistent with previous work that suggests pain has an overall dampening effect. Furthermore, when the valence category of the word was pain-related, T2 accuracy performance was negatively affected.

CONCLUSION

These findings add to the previous evidence that pain has a general dampening effect on attention and that pain-related stimuli are difficult to disengage from.

SIGNIFICANCE

Pain captures attention to allow cognate resources to be directed appropriately in response. However, the temporal effects of this attentional capture are poorly understood. Findings indicate that acute headache pain has a negative impact on participants' performance when identifying the second of two targets presented in close temporal proximity, and that pain-valenced stimuli exacerbate this effect. These findings demonstrate how pain affects early attention and highlights the potential role of disengagement, rather than orientation, of attention in the pain experience.

Prioritizing Pain-Associated Targets with Machine Learning

While hundreds of genes have been associated with pain, much of the molecular mechanisms of pain remain unknown. As a result, current analgesics are limited to few clinically validated targets. Here, we trained a machine learning (ML) ensemble model to predict new targets for 17 categories of pain. The model utilizes features from transcriptomics, proteomics, and gene ontology to prioritize targets for modulating pain. We focused on identifying novel G-protein-coupled receptors (GPCRs), ion channels, and protein kinases because these proteins represent the most successful drug target families. The performance of the model to predict novel pain targets is 0.839 on average based on AUROC, while the predictions for arthritis had the highest accuracy (AUROC = 0.929). The model predicts hundreds of novel targets for pain; for example, GPR132 and GPR109B are highly ranked GPCRs for rheumatoid arthritis. Overall, gene-pain association predictions cluster into three groups that are enriched for cytokine, calcium, and GABA-related cell signaling pathways. These predictions can serve as a foundation for future experimental exploration to advance the development of safer and more effective analgesics.

Is clinical, musculoskeletal pain associated with poorer logical reasoning?

Clinical pain does not seem to be considerably related to logical reasoning ability, which seems consistent with the effect of experimental pain on logical reasoning.

Introduction:

It has been hypothesized that pain disrupts system 2 processes (eg, working memory) presumed to underlie logical reasoning. A recent study examining the impact of experimentally induced pain on logical reasoning found no evidence of an effect.

Objectives:

The aim of this study was to examine whether clinical pain, which is qualitatively different from experimental pain, would lower the ability to reason logically.

Methods:

Ninety-six participants completed a questionnaire containing 3 different logical reasoning tasks (the cognitive reflection test, the belief bias syllogisms task, and the conditional inference task), questions about pain variables (present pain intensity, pain intensity during the last 24 hours, the influence of pain on daily activities, pain duration, and pain persistence), questions about other pain-related states (anxiety, depression, and fatigue), and pain-relieving medication. Correlations between the logical reasoning tasks and the pain variables were calculated.

Results:

For 2 of the 3 logical reasoning tasks (the cognitive reflection test and the belief bias syllogisms task), clinical pain was unrelated to logical reasoning. Performance on context-free logical reasoning showed a significant negative correlation with present pain intensity, but not with the other pain variables.

Conclusion:

This finding that logical reasoning ability is largely unrelated to clinical pain is highly consistent with previous research on experimentally induced pain. Pain should probably not constitute a significant barrier to logical reasoning in everyday life.

Neuropathic pain-induced cognitive dysfunction and down-regulation of neuronal pentraxin 2 in the cortex and hippocampus

Evidence from both basic and clinical science suggests that neuropathic pain can induce cognitive dysfunction. However, these results are mainly based on a series of behavioral tests, there is a lack of quantitative variables to indicate cognitive impairment. Neuronal activity-regulated pentraxin (NPTX2) is a ubiquitously expressed, secreted protein in the nervous system. NPTX2 has been implicated to be involved in a variety of neuropathic diseases including Parkinson's disease, ischemia, and Alzheimer's disease. In a mouse model of chronic pain, NPTX2 is involved in the regulation of inflammatory responses. Here, we employ a variety of behavioral approaches to demonstrate that mice with chronic neuropathic pain have cognitive impairment and exhibit an increased anxiety response. The expression of NPTX2, but not NPTX1, was down-regulated in the hippocampus and cortex after chronic neuropathic pain exposure. The modulation effect of NPTX2 on cognitive function was also verified by behavioral tests using Nptx2 knock-out mice. Above all, we conclude that downregulation of NPTX2 induced by neuropathic pain may serve as an indicator of a progressive cognitive dysfunction during the induction and maintenance of spared nerve injury.

Reversal of peripheral nerve injury-induced neuropathic pain and cognitive dysfunction via genetic and tomivosertib targeting of MNK

Neuropathic pain caused by nerve injury presents with severe spontaneous pain and a variety of comorbidities, including deficits in higher executive functions. None of these clinical problems are adequately treated with current analgesics. Targeting of the mitogen-activated protein kinase-interacting kinase (MNK1/2) and its phosphorylation target, the mRNA cap binding protein eIF4E, attenuates many types of nociceptive plasticity induced by inflammatory mediators and chemotherapeutic drugs but inhibiting this pathway does not alter nerve injury-induced mechanical allodynia. We used genetic manipulations and pharmacology to inhibit MNK-eIF4E activity in animals with spared nerve injury, a model of peripheral nerve injury (PNI)-induced neuropathic pain. We assessed the presence of spontaneous pain using conditioned place preference. We also tested performance in a medial prefrontal cortex (mPFC)-dependent rule-shifting task. WT neuropathic animals showed signs of spontaneous pain and were significantly impaired in the rule-shifting task while genetic and pharmacological inhibition of the MNK-eIF4E signaling axis protected against and reversed spontaneous pain and PNI-mediated cognitive impairment. Additionally, pharmacological and genetic inhibition of MNK-eIF4E signaling completely blocked and reversed maladaptive shortening in the length of axon initial segments (AIS) in the mPFC of PNI mice. Surprisingly, these striking positive outcomes on neuropathic pain occurred in the absence of any effect on mechanical allodynia, a standard test for neuropathic pain efficacy. Our results illustrate new testing paradigms for determining preclinical neuropathic pain efficacy and point to the MNK inhibitor tomivosertib (eFT508) as an important drug candidate for neuropathic pain treatment.