Counterirritation by pain inhibits the responsiveness to aversive loud tones: the role of state anxiety and state fear triggered in the NPU paradigm.

AIM OF THE STUDY: The application of a noxious stimulus reduces the perception and responsiveness to other pain stimuli. This inhibition can be experimentally assessed with a method called 'counterirritation'. The question arises if counterirritation acts also on the perception and responsiveness to aversive but non-nociceptive stimuli (e.g., loud tones). Since aversive stimulation is often associated with state anxiety or state fear, we investigated in addition the modulatory effects of these emotions on counterirritation. MATERIAL AND METHODS: 51 subjects participated in our study. We presented tones with aversive loudness (105 dB), first alone then during counterirritation (immersion of the hand in a hot water bath of 46 °C) to assess inhibition of loudness perception and responsiveness. Influences of state anxiety and state fear on counterirritation were investigated by using the Neutral-Predictable(fear)- Unpredictable(anxiety) Paradigm (NPU), which is based on classical conditioning. Loudness ratings (perception of the aversive tones) and startle reflex (defensive reaction to aversive tones) were assessed. RESULTS: Counterirritation reduced startle reflex amplitudes, but not the loudness ratings. Although state anxiety and state fear were successfully induced, counterirritation remained unaffected. CONCLUSIONS: Our study showed that pain inhibits the responsiveness to aversive stimuli (loud tones). Thus, the postulate that 'pain inhibits pain' might be better changed to 'pain inhibits aversiveness'. Consequently, our findings may also question the assumption of a clear pain specificity in inhibitory action as assumed by theoretical approaches like 'conditioned pain modulation' (CPM). Furthermore, counterirritation appeared one more time resistant to the influence of negative emotions.

Sex differences in facial expressions of pain: results from a combined sample.

ABSTRACT: Facial expressions of pain play an important role in pain diagnostics and social interactions. Given the prominent impact of sex on various aspects of pain, it is not surprising that sex differences have also been explored regarding facial expressions of pain; however, with inconclusive findings. We aim to further investigate sex differences in facial expressions of pain by using a large, combined sample to maximize statistical power. Data from 7 previous studies of our group were merged, combining in total the data of 392 participants (male: 192, female: 200). All participants received phasic heat pain, with intensities being tailored to the individual pain threshold. Pain intensity ratings were assessed, and facial responses were manually analyzed using the Facial Action Coding. To compare facial and subjective responses between sexes, linear mixed-effects models were used, with study ID as a random effect. We found significant sex differences in facial responses, with females showing elevated facial responses to pain, although they received lower physical heat intensities (women had lower pain thresholds). In contrast, pain intensity ratings did not differ between sexes. Additionally, facial and subjective responses to pain were significantly associated across sexes, with females showing slightly stronger associations. Although variations in facial expressions of pain are very large even within each sex, our findings demonstrate that women facially communicate pain more intensively and with a better match to their subjective experience compared with men. This indicates that women might be better in using facial communication of pain in an intensity-discriminative manner.

Higher Subjective Burden in Psychiatric Compared to Somatic Healthcare Workers in Germany During the first wave of the COVID-19 Pandemic.

The COVID-19 pandemic has posed unprecedented challenges for health care workers (HCWs) worldwide. While the adverse effects of the pandemic on the well-being of HCWs in general have now been established, little is known about the impact on HCWs of psychiatric hospitals (PHCWs). PHCWs are of special interest, given that they faced both an increase in infection rates among psychiatric patients as well as in mental strain of the general public due to consequences of the pandemic. The aim of the present study was to investigate how the pandemic affected PHCWs as well as possible differences between PHCWs and other health care workers (OHCWs) in Germany during the first wave of the pandemic. We conducted a country-wide anonymous online survey early during the first pandemic wave between April 15th and May 1st, 2020, to assess different aspects of subjective burden and perceived stress using 5-point Likert-scale questions. We analysed data of 1530 PHCWs and 2114 OHCWs and showed that PHCWs reported higher subjective burden and stress compared to OHCWs (p<0.001). Overall, nurses from both groups of HCWs showed higher ratings in subjective burden and stress than physicians. These higher ratings for subjective burden were even more pronounced for nurses working in psychiatric hospitals. Future research is needed to investigate the causes for PHCWs' increased stress and subjective burden, especially when taking into account the long-term effects of the pandemic, which may lead to further challenges and an ever-increasing workload, especially for PHCWs.

Is conditioned pain modulation (CPM) affected by negative emotional state?

BACKGROUND: Conditioned pain modulation (CPM) is an experimental paradigm, which describes the inhibition of responses to a noxious or strong-innocuous stimulus, the test stimulus (TS), by the additional application of a second noxious or strong-innocuous stimulus, the conditioning stimulus (CS). As inadequate CPM efficiency has been assumed to be predisposing for clinical pain, the search for moderating factors explaining inter-individual variations in CPM is ongoing. Psychological factors have received credits in this context. However, research concerning associations between CPM and trait factors relating to negative emotions has yielded disappointing results. Yet, the influence of anxious or fearful states on CPM has not attracted much interest despite ample evidence that negative affective states enhance pain. Our study aimed at investigating the effect of fear induction by symbolic threat on CPM. METHODS: Thirty-seven healthy participants completed two experimental blocks: one presenting aversive pictures showing burn wounds (high-threat block) and one presenting neutral pictures (low-threat block). Both blocks contained a CPM paradigm with contact heat as TS and hot water as CS; subjective numerical ratings as well as contact-heat evoked potentials (CHEPs) were assessed. RESULTS: We detected an overall inhibitory CPM effect for CHEPs amplitudes but not for pain ratings. However, we found no evidence for a modulation of CPM by threat despite threat ratings indicating that our manipulation was successful. DISCUSSION: These results suggest that heat/thermal CPM is resistant to this specific type of symbolic threat induction and further research is necessary to examine whether it is resistant to fearful states in general. SIGNIFICANCE: The attempt of modulating heat conditioned pain modulation (CPM) by emotional threat (fear/anxiety state) failed. Thus, heat CPM inhibition again appeared resistant to emotional influences. Pain-related brain potentials proved to be more sensitive for CPM effects than subjective ratings.

Vicarious facilitation of facial responses to pain.

INTRODUCTION: Observing facial expressions of pain has been shown to lead to increased subjective, neural and autonomic pain responses. Surprisingly, these vicarious facilitation effects on its corresponding response channel, namely facial responses to pain have mostly been neglected. We aim to examine whether the prior exposure to facial expressions of pain leads to a facilitation of facial responses to experimental pain; and whether this facilitation is linked to the valence (pain vs. neutral expression) or also linked to specific motor-features of the facial pain expressions (different facial muscle movements). METHOD: Subjective (intensity and unpleasantness ratings) and facial responses (Facial Action Coding System) of 64 participants (34 female) to painful and non-painful heat stimuli were assessed. Before each heat stimulus, video clips of computer-generated facial expressions (three different pain expressions and a neutral expression) were presented. RESULTS: The prior exposure to facial expressions of pain led to increased subjective and facial responses to pain. Further, vicarious pain facilitation of facial responses was significantly correlated with facilitation of unpleasantness ratings. We also found evidence that this vicarious facilitation of facial responses was not only linked to the presentation of pain versus neutral expressions but also to specific motor-features of the pain cue (increase in congruent facial muscle movements). DISCUSSION: Vicarious pain facilitation was found for subjective and facial responses to pain. The results are discussed with reference to the motivational priming hypothesis as well as with reference to motor priming. SIGNIFICANCE: Our study uncovers evidence that facial pain responses are not only influenced by motivational priming (similar to other types of pain responses), but also by motor-priming. These findings shed light on the complexity - ranging from social, affective and motor mechanisms - underling vicarious facilitation of pain.

Structural Disorder at the Edges of Rubrene Crystals Enhances Singlet Fission.

Materials that undergo singlet fission are of interest for their use in light-harvesting, photocatalysis, and quantum information science, but their ability to undergo fission can be sensitive to local variations in molecular packing. Herein we employ transient absorption microscopy, molecular dynamics simulations, and electronic structure calculations to interrogate how structures found at the edges of orthorhombic rubrene crystals impact singlet fission. Within a micrometer-scale spatial region at the edges of rubrene crystals, we find that the rate of singlet fission increases nearly 4-fold. This observation is consistent with formation of a region at crystal edges with reduced order that accelerates singlet fission by disrupting the symmetry found in rubrene's orthorhombic crystal structure. Our work demonstrates that structural distortions of singlet fission materials can be used to control fission in time and in space, potentially offering a means of controlling this process in light harvesting and quantum information applications.

Facial expressions of pain: the role of the serotonergic system.

RATIONALE: Although interest in the neurobiology of facial communication of pain has increased over the last decades, little is known about which neurotransmitter systems might be involved in regulating facial expressions of pain. OBJECTIVES: We aim to investigate whether the serotonergic system (5-HT), which has been implicated in various aspects of pain processing as well as in behavioral response inhibition, might play a role in facial expressions of pain. Using acute tryptophan depletion (ATD) to manipulate 5-HT function, we examined its effects on facial and subjective pain responses. METHODS: In a double-blind, placebo-controlled within-subject design, 27 participants received either an ATD or a control drink in two separate sessions. Approximately 5-h post-oral consumption, we assessed pain thresholds (heat, pressure) as well as facial and subjective responses to phasic heat pain. Moreover, situational pain catastrophizing and mood were assessed as affective state indicators. RESULTS: ATD neither influenced pain thresholds nor self-report ratings, nor catastrophizing or mood. Only facial responses were significantly affected by ATD. ATD led to a decrease in pain-indicative as well as in pain-non-indicative facial responses to painful heat, compared to the control condition. CONCLUSIONS: Decrease in brain 5-HT synthesis via ATD significantly reduced facial responses to phasic heat pain; possibly due to (i) diminished disposition to display social behavior or due to (ii) decreased facilitation of excitatory inputs to the facial motor neuron.

Spatial Heterogeneity of Biexcitons in Two-Dimensional Ruddlesden-Popper Lead Iodide Perovskites.

Quantum confinement in two-dimensional (2D) Ruddlesden-Popper (RP) perovskites leads to the formation of stable quasi-particles, including excitons and biexcitons, the latter of which may enable lasing in these materials. Due to their hybrid organic-inorganic structures and the solution phase synthesis, microcrystals of 2D RP perovskites can be quite heterogeneous, with variations in excitonic and biexcitonic properties between crystals from the same synthesis and even within individual crystals. Here, we employ one- and two-quantum two-dimensional white-light microscopy to systematically study the spatial variations of excitons and biexcitons in microcrystals of a series of 2D RP perovskites BA2MAn-1PbnI3n+1 (n = 2-4, BA= butylammonium, MA = methylammonium). We find that the average biexciton binding energy of around 60 meV is essentially independent of the perovskite layer thickness (n). We also resolve spatial variations of the exciton and biexciton energies on micron length scales within individual crystals. By comparing the one-quantum and two-quantum spectra at each pixel, we conclude that biexcitons are more sensitive to their environments than excitons. These results shed new light on the ways disorder can modify the energetic landscape of excitons and biexcitons in RP perovskites and how biexcitons can be used as a sensitive probe of the microscopic environment of a semiconductor.

Facial expression is a distinctive behavioural marker of pain processing in the brain.

Pain is a private experience observable through various verbal and non-verbal behavioural manifestations. Despite the importance of understanding the cerebral mechanisms underlying those manifestations, there is currently limited knowledge on the neural correlates of facial expression of pain. Here, we applied a brain decoding approach to functional magnetic resonance imaging (fMRI) data to predict the facial expression of pain during noxious heat stimulation in healthy volunteers. Results revealed the inability of previously developed pain neurosignatures to predict the facial expression of pain. We thus propose a Facial Expression of Pain Signature (FEPS) conveying distinctive information about the brain response to nociceptive stimulations with minimal overlap with other pain-relevant brain signatures. The FEPS provides a better characterization of the distributed cerebral representations of non-verbal pain communication. This underscores the complexity of pain phenomenology by reinforcing the view that neurosignatures conceived as biomarkers must be interpreted in relation to the specific pain manifestation predicted.

Brain mechanisms associated with facial encoding of affective states.

Affective states are typically accompanied by facial expressions, but these behavioral manifestations are highly variable. Even highly arousing and negative valent experiences, such as pain, show great instability in facial affect encoding. The present study investigated which neural mechanisms are associated with variations in facial affect encoding by focusing on facial encoding of sustained pain experiences. Facial expressions, pain ratings, and brain activity (BOLD-fMRI) during tonic heat pain were recorded in 27 healthy participants. We analyzed facial expressions by using the Facial Action Coding System (FACS) and examined brain activations during epochs of painful stimulation that were accompanied by facial expressions of pain. Epochs of facial expressions of pain were coupled with activity increase in motor areas (M1, premotor and SMA) as well as in areas involved in nociceptive processing, including primary and secondary somatosensory cortex, posterior and anterior insula, and the anterior part of the mid-cingulate cortex. In contrast, prefrontal structures (ventrolateral and medial prefrontal) were less activated during incidences of facial expressions, consistent with a role in down-regulating facial displays. These results indicate that incidences of facial encoding of pain reflect activity within nociceptive pathways interacting or possibly competing with prefrontal inhibitory systems that gate the level of expressiveness.

Relationship between chronotype and pain threshold in a sample of young healthy adults.

Introduction: Chronotype indicates the biological preference for timing of activity and sleep. Being a late chronotype (ie, having a tendency for late sleep times) is associated with several mental and physical health problems. Previous studies found that late chronotypes are also more susceptible to chronic pain, but the relationship between chronotype and pain sensitivity remains unclear. Objectives: The aim of this study was to investigate the relationship between chronotype and heat pain threshold (as an indicator of pain sensitivity) in a sample of young healthy adults. Methods: We analyzed data from 316 young healthy adults participating in 4 different studies run at the Medical Faculty of the University of Augsburg. In all studies, chronotype and other sleep variables (eg, sleep duration) were assessed using the micro Munich ChronoType Questionnaire. Heat pain threshold was assessed with the method of adjustment. Results: Chronotype was not significantly associated with the heat pain threshold. Entering the other sleep variables in separate regression models did also not significantly explain variance in heat pain threshold. Conclusion: Our null findings are in contrast with previous notions that late chronotypes might be more sensitive to pain and more susceptible to chronic pain. Given the scarcity of the literature on this topic, more studies are needed to clarify the relationship between chronotype and pain sensitivity in different age populations, while also considering distinct pain modalities or other types of pain tests.

Differences Between East Asians and Westerners in the Mental Representations and Visual Information Extraction Involved in the Decoding of Pain Facial Expression Intensity.

Effectively communicating pain is crucial for human beings. Facial expressions are one of the most specific forms of behavior associated with pain, but the way culture shapes expectations about the intensity with which pain is typically facially conveyed, and the visual strategies deployed to decode pain intensity in facial expressions, is poorly understood. The present study used a data-driven approach to compare two cultures, namely East Asians and Westerners, with respect to their mental representations of pain facial expressions (experiment 1, N=60; experiment 2, N=74) and their visual information utilization during the discrimination of facial expressions of pain of different intensities (experiment 3; N=60). Results reveal that compared to Westerners, East Asians expect more intense pain expressions (experiments 1 and 2), need more signal, and do not rely as much as Westerners on core facial features of pain expressions to discriminate between pain intensities (experiment 3). Together, those findings suggest that cultural norms regarding socially accepted pain behaviors shape the expectations about pain facial expressions and decoding visual strategies. Furthermore, they highlight the complexity of emotional facial expressions and the importance of studying pain communication in multicultural settings. Supplementary Information: The online version contains supplementary material available at 10.1007/s42761-023-00186-1.

What do healthcare workers need? A qualitative study on support strategies to protect mental health of healthcare workers during the SARS-CoV-2 pandemic.

BACKGROUND: To support healthcare workers (HCWs) during the increased burden caused by the SARS-CoV-2 pandemic, numerous recommendations for action and possible interventions have been developed. However, the actual protective factors, needs and desires of those affected, as well as potential barriers to implementing psychological interventions, have been insufficiently examined. This study addresses this research gap and captures HCWs' experiences and views. METHODS: Medical personnel including nursing staff and physicians were recruited for a qualitative study regarding protective factors as well as barriers to the implementation of support services. We conducted 21 individual, semi-structured interviews with members of the medical staff at tertiary care center in Germany. The collected data were analyzed using a qualitative content analysis. RESULTS: The analyses showed that social interaction in the professional and private context was rated as helpful in coping with the challenges of everyday work amplified by the SARS-CoV-2 pandemic. The results also suggest that the available support services, despite being highly valued, were rarely accessed. Possible barriers included the fear of negative consequences when asking for support. It could be deduced that the fear and shame of admitting one's own mistakes as well as the work-related tradition of showing no weakness could be the underlying factors for this fear. RESULTS: The results of this study suggest that medical staff need a more extensive range of low-threshold support services, which should be adapted to the respective needs of the professional groups. The study also provides indications that the norms and expectations represented in the hospital system require critical reflection.

How gender affects the decoding of facial expressions of pain.

OBJECTIVES: Gender has been suggested to play a critical role in how facial expressions of pain are perceived by others. With the present study we aim to further investigate how gender might impact the decoding of facial expressions of pain, (i) by varying both the gender of the observer as well as the gender of the expressor and (ii) by considering two different aspects of the decoding process, namely intensity decoding and pain recognition. METHODS: In two online-studies, videos of facial expressions of pain as well as of anger and disgust displayed by male and female avatars were presented to male and female participants. In the first study, valence and arousal ratings were assessed (intensity decoding) and in the second study, participants provided intensity ratings for different affective states, that allowed for assessing intensity decoding as well as pain recognition. RESULTS: The gender of the avatar significantly affected the intensity decoding of facial expressions of pain, with higher ratings (arousal, valence, pain intensity) for female compared to male avatars. In contrast, the gender of the observer had no significant impact on intensity decoding. With regard to pain recognition (differentiating pain from anger and disgust), neither the gender of the avatar, nor the gender of the observer had any affect. CONCLUSIONS: Only the gender of the expressor seems to have a substantial impact on the decoding of facial expressions of pain, whereas the gender of the observer seems of less relevance. Reasons for the tendency to see more pain in female faces might be due to psychosocial factors (e.g., gender stereotypes) and require further research.

Time-Domain Photothermal AFM Spectroscopy via Femtosecond Pulse Shaping.

A time-domain version of photothermal microscopy using an atomic force microscope (AFM) is reported, which we call Fourier transform photothermal (FTPT) spectroscopy, where the delay between two laser pulses is varied and the Fourier transform is computed. An acousto-optic modulator-based pulse shaper sets the delay and phases of the pulses shot-to-shot at 100 kHz, enabling background subtraction and data collection in the rotating frame. The pulse shaper is also used to flatten the pulse spectrum, thereby eliminating the need for normalization by the laser spectrum. We demonstrate the method on 6,13-bis(triisopropylsilylethynyl)pentacene (TIPS-Pn) microcrystals and Mn-phthalocyanine islands, confirming subdiffraction spatial resolution, and providing new spectroscopic insights likely linked to structural defects in the crystals.

Perceived risk of COVID-19 exposure and poor COVID-19 prognosis impair sleep: The mediating and moderating roles of COVID-19-related anxiety and knowledge.

The ongoing COVID-19 pandemic has been linked to increased levels of stress, depression, and anxiety in many people around the world. Therefore, identifying individuals at risk of psychosocial burden during this unprecedented crisis is essential for developing prevention measures and treatment options for mental health issues. To this aim, we investigated two risk groups: individuals at higher risk of exposure to the virus and individuals at higher risk of poor prognosis if they contract the virus. We conducted a survey (N = 4167) with a representative sample of the German population and assessed perceived risk of COVID-19 exposure and poor prognosis if infected, COVID-19-related anxiety, problems with sleep and daytime functioning, as well as self-reported knowledge about the disease. Results showed that perceived risk group membership was linked to increased problems with sleep and daytime functioning via elevated levels of COVID-19-related anxiety. This mediated effect was further moderated by self-reported COVID-19 knowledge, but only for individuals who rated themselves at higher risk of COVID-19 exposure. Thus, knowledge buffered the negative effect of exposure risk on anxiety and ultimately on sleep in this risk group. Reaching individuals at increased risk of exposure with clear information about the disease, how to prevent infection, and treatment options could be an effective strategy to contain anxiety levels and promote good sleep, which is important for general well-being.

Towards a Better Understanding on How Cognitive Impairment Affects Pain.

When judging whether someone is suffering from pain, the simplest and most reliable solution is to ask that person about it [...].

[Prevention and Health Promotion during Studies: Suggestions for an Interdisciplinary Curriculum in Medicine and Educational Science]. / Prävention und Gesundheitsförderung im Studium: Vorschläge für ein interdisziplinäres Curriculum in den Studiengängen Humanmedizin und Erziehungswissenschaft.

In academic medicine, the growing importance of disease prevention and health promotion poses new challenges. Besides diseases, the focus must also be on health resources and competences in order to promote health and to prevent diseases or their prolonged manifestation. These aspects must already be integrated into medical education in order to equip future professionals. With the aim of integrating health promotion and disease prevention more strongly in the curriculum and strengthening the interdisciplinary collaboration between physicians and other health care professionals, a prototypical longitudinal model curriculum is being developed for students of medicine and educational science with a focus on health pedagogy at Augsburg University. Students learn about health promotion strategies in the University setting, gain initial interdisciplinary experience and then plan and implement health promotion initiatives for their fellow students in smaller projects as peers. The intention is to make the university setting more health-promoting for as well as by students.The model curriculum is intended to provide other university locations with "good practice" examples that can then be locally adapted and integrated into the respective curricula.

Automatic Coding of Facial Expressions of Pain: Are We There Yet?

INTRODUCTION: The experience of pain is regularly accompanied by facial expressions. The gold standard for analyzing these facial expressions is the Facial Action Coding System (FACS), which provides so-called action units (AUs) as parametrical indicators of facial muscular activity. Particular combinations of AUs have appeared to be pain-indicative. The manual coding of AUs is, however, too time- and labor-intensive in clinical practice. New developments in automatic facial expression analysis have promised to enable automatic detection of AUs, which might be used for pain detection. OBJECTIVE: Our aim is to compare manual with automatic AU coding of facial expressions of pain. METHODS: FaceReader7 was used for automatic AU detection. We compared the performance of FaceReader7 using videos of 40 participants (20 younger with a mean age of 25.7 years and 20 older with a mean age of 52.1 years) undergoing experimentally induced heat pain to manually coded AUs as gold standard labeling. Percentages of correctly and falsely classified AUs were calculated, and we computed as indicators of congruency, "sensitivity/recall," "precision," and "overall agreement (F1)." RESULTS: The automatic coding of AUs only showed poor to moderate outcomes regarding sensitivity/recall, precision, and F1. The congruency was better for younger compared to older faces and was better for pain-indicative AUs compared to other AUs. CONCLUSION: At the moment, automatic analyses of genuine facial expressions of pain may qualify at best as semiautomatic systems, which require further validation by human observers before they can be used to validly assess facial expressions of pain.

Observing Pain in Individuals with Cognitive Impairment: A Pilot Comparison Attempt across Countries and across Different Types of Cognitive Impairment.

Facial expression is a key aspect in observational scales developed to improve pain assessment in individuals with cognitive impairments. Although these scales are used internationally in individuals with different types of cognitive impairments, it is not known whether observing facial expressions of pain might differ between regions or between different types of cognitive impairments. In a pilot study, facial responses to standardized experimental pressure pain were assessed among individuals with different types of cognitive impairments (dementia, mild cognitive impairment, Huntington's disease, and intellectual disability) from different countries (Denmark, Germany, Italy, Israel, and Spain) and were analyzed using facial descriptors from the PAIC scale (Pain Assessment in Impaired Cognition). We found high inter-rater reliability between observers from different countries. Moreover, facial responses to pain did not differ between individuals with dementia from different countries (Denmark, Germany, and Spain). However, the type of cognitive impairment had a significant impact; with individuals with intellectual disability (all being from Israel) showing the strongest facial responses. Our pilot data suggest that the country of origin does not strongly affect how pain is facially expressed or how facial responses are being scored. However, the type of cognitive impairment showed a clear effect in our pilot study, with elevated facial responses in individuals with intellectual disability.