"And how did that make you feel?" - Repeated symptom queries enhance symptom reports elicited by negative affect

OBJECTIVE

Negative affect, alexithymia, and other predisposing traits (such as health anxiety) can influence an individual's symptom perception. In this study, we used the affective picture paradigm (APP, Bogaerts et al., 2010) to induce symptoms using affective picture stimuli. We aimed to cross-sectionally test the effect of high vs low-frequency symptom queries and analyze the time course of the APP, including interactions with health anxiety and somatic symptom distress.

METHODS

Participants (N = 124) completed a modified APP and filled out various questionnaires. In the APP, participants were randomized to either a highly-frequent-query condition (18 symptom checklists) or a less-frequent-query condition (6 checklists). Data were analyzed using ANOVAs, cross-lagged panel models, moderation models, and multilevel models.

RESULTS

Both groups had comparable symptom baseline values, but people in the highly frequent as opposed to less frequent condition reported significantly higher symptom levels once the experiment started (F (1,120) = 14.319, p < .001, η2=.107). Symptom levels stayed stable over the course of the experiment and were best predicted by symptom levels at earlier timepoints in the experiment (β = 0.43 and β = 0.68, both p < .001). Health anxiety levels significantly predicted symptom levels (F(1,121) = 10.054, p = .002, η2=.077) and moderated the relation between condition and symptom levels (F(2,121) = 16.253, p < .001, η2=.212).

CONCLUSION

In terms of the predictive processing model (e.g.,[1]), repeated symptom queries following negative affective cues may activate prior beliefs about symptoms, resulting in elevated levels of symptom reports in interaction with health anxiety.

Heart rate perception and expectation impact laboratory-induced perceived stress

Previous studies have shown that the human capacity to gauge one's own physiological state is notoriously flawed. The cause for the mismatch between perceived and physiological stress has not yet been properly identified. In this study, we assumed that cardioceptive accuracy (CAc) is positively associated with cardiovascular reactivity, and CAc and expectation about stress might account for the discrepancy between perceived and physiological stress. In a crossover experiment, we assessed cardioceptive accuracy in two ways (mental heartbeat tracking task and perception of heart rate), and induced physiological (handgrip exercise) and mental (N-back task) stress in 64 university students (51 % male, mean age 22.2). We assessed cardiac and electrodermal activity, and expected and perceived stress. We found that indicators of cardioceptive accuracy were not associated with cardiovascular reactivity. However, heart rate perception moderated the association between the change in heart rate and perceived stress in the physical but not in the mental task. Whereas heartbeat tracking accuracy was not associated with perceived stress. Moreover, perceived stress was predicted by the expected stress but not by the change in heart rate and electrodermal activity in the mental stress task. In conclusion, heart rate perception and expectation of stress may shape perceived stress more than actual physiological changes in moderate acute stress.

The Effects of Essential Oils on the Nervous System: A Scoping Review

Essential oils are a mixture of natural aromatic volatile oils extracted from plants. The use of essential oils is ancient, and has prevailed in different cultures around the world, such as those of the Egyptians, Greeks, Persians, and Chinese. Today, essential oils are used in traditional and complimentary medicines, aromatherapy, massage therapies, cosmetics, perfumes and food industries. The screening effect of essential oils has been studied worldwide. They demonstrate a range of biological activities, such as antiparasitic, antifungal, antibacterial, antiviral, antioxidant, anti-inflammatory, anticancer, antiaging, and neuroprotective properties. In this scoping review, we provide a 10-year updated comprehensive assessment of volatile oils and their effects on the nervous system. MEDLINE, Scopus, and Google Scholar were systematically and strategically searched for original studies investigating these effects from 2012 to 2022. Approximately seventy studies were selected as included studies. Among these studies, several outcomes were reported, including antistress, antianxiety, analgesic, cognitive, and autonomic effects. Some essential oils showed developmental benefits, with the potential to induce neurite outgrowth. The neurotransmitter receptor level can also be modified by essential oil application. Physiological and pathophysiological outcome measures were reported. For physiological outcomes, arousal, cognitive performance, circadian eating behavior, emotional modulation, consumer acceptance, preferences, and willingness to buy were investigated. For pathophysiological conditions, pain, depression, anxiety, stress, sleep disorder, mental fatigue, agitated behavior, and quality of life were measured. In conclusion, essential oils showed promising effects on the nervous system, which can be further applied to their use in functional foods, drinks, and alternative therapy.

Mental heartbeat tracking and rating of emotional pictures are not related

Our aim was to conceptually replicate the findings of previous empirical studies showing that people with higher cardiac interoceptive accuracy experience more intense emotions. Apart of the mental heartbeat tracking task of Schandry, Hungarian (n = 46, 76.0% female, mean age 22.28 ± 2.228) and Norwegian (n = 50, 60.0% female, mean age 24.66 ± 3.048) participants rated the arousal and valence evoked by positive, neutral and negative pictures. Multivariate repeated analysis of variance (applying both frequentist and Bayesian approaches) did not reveal any connection between heartbeat perception scores and the subjective ratings (i.e., arousal and valence) of the pictures in any of the two groups. The lack of the expected association between cardioceptive accuracy and arousal might partly be explained by the methodological differences between previous studies and this one; for example, we did not split or preselected the sample based on the performance on the Schandry task and applied a relatively strict instruction (i.e., by encouraging to count felt heartbeats only, and to report zero if no sensations were detected).

Role of endothelin receptor type A on catecholamine regulation in the olfactory bulb of DOCA-salt hypertensive rats: Hemodynamic implications

Increasing evidence shows that the olfactory bulb is involved in blood pressure regulation in health and disease. Enhanced noradrenergic transmission in the olfactory bulb was reported in hypertension. Given that endothelins modulate catecholamines and are involved in the pathogenesis of hypertension, in the present study we sought to establish the role of the endothelin receptor type A on tyrosine hydroxylase, the rate limiting enzyme in catecholamine biosynthesis, in the olfactory bulb of DOCA-salt hypertensive rats. Sprague-Dawley male rats, randomly divided into Control and DOCA-Salt hypertensive groups, were used to assess endothelin receptors by Western blot and confocal microscopy, and their co-localization with tyrosine hydroxylase in the olfactory bulb. Blood pressure and heart rate as well as tyrosine hydroxylase expression and activity were assessed following BQ610 (ET_A antagonist) applied to the brain. DOCA-Salt hypertensive rats showed enhanced ET_A and decreased ET_B expression. ET_A co-localized with tyrosine hydroxylase positive neurons. Acute ET_A blockade reduced blood pressure and heart rate and decreased the expression of total tyrosine hydroxylase and its phosphorylated forms. Furthermore, it also diminished mRNA tyrosine hydroxylase expression and accelerated the enzyme degradation through the proteasome pathway as shown by pretreatment with MG132, (20s proteasome inhibitor) intracerebroventricularly applied. Present findings support that the brain endothelinergic system plays a major role through ET_A activation in the increase of catecholaminergic activity in the olfactory bulb of DOCA-Salt hypertensive rats. They provide rationale evidence that this telencephalic structure contributes in a direct or indirect way to the hemodynamic regulation in salt dependent hypertension.

Anti-depressive-like effect of 2-phenylethanol inhalation in mice

Rose oil has traditionally been used to treat psychiatric disorders, but the scientific basis of this treatment remains poorly understood. The main odor component of rose oil is 2-phenylethanol (2-PE), but the neuropsychological effects of 2-PE have not been investigated in detail. Thus, we aimed to investigate the effects of 2-PE on mouse behavior. We first investigated whether 2-PE is attractive or repulsive to mice. After 2-PE inhalation, the mice underwent a series of behavioral experiments, such as the elevated plus maze, open field, Y-maze, tail-suspension, and Porsolt forced-swim tests. Mice did not have a strong interest in 2-PE but were not repelled by it nor were fearful. In the open field test, mice that had inhaled 2-PE spent less time in the center area, while in the tail suspension test, their immobility time decreased. There was no change in cognitive function, activity level, muscle strength, or aggression in these mice. Our results suggest that 2-PE elicits neuropsychological effects that alter the behavior of mice and may also elicit anti-depressive effects. Inhalation of rose oil containing 2-PE may be effective against depression and stress-related diseases.

Super Pill is Less Effective than an Ordinary Mint in Altering Subjective Psychological Feeling States within a Few Minutes

Expectations shape human behavior. Initial drug use might be associated with information-based expectations. In this study, we presumed that changes in affect and perceived physical wellbeing will be stronger after receiving an active placebo (Tic Tac mint; n = 40), than a pure placebo (inert pill; n = 40) given as a mood-enhancing "super pill." After baseline measures, participants completed a treatment-expectancy scale, ingested the mint/super pill, and attended to the effects over 3-minutes. Subsequently, they completed again the psychological tests. Expectancy scores were positive and did not differ between the groups. The pure placebo group increased in physical wellbeing but less than the active placebo group, which also showed an increase in positive affect. Negative affect decreased in both groups. The Tic Tac produced greater affective changes than the pure placebo. Since these are new findings on the ultra-short placebo effects on affect, the results might have relevance for drug-use studies.

No effect of a pulsed magnetic field on induced ischemic muscle pain. A double-blind, randomized, placebo-controlled trial

Empirical evidence supporting the effectiveness of pulsed (electro)magnetic field (PEMF) therapy on chronic and acute pain is equivocal. In the current randomized, double-blind, placebo-controlled experiment, impact of a commercially available whole-body PEMF mat on acute ischemic muscle pain induced in the forearm was studied with the participation of 70 healthy volunteers. The device emitted a pulsed magnetic field with a repetition frequency of 2.05Hz and a maximum flux density of 25.3μT (rms). The highest dB/dt was 48mT/s. No differences between the groups receiving actual and sham PEMF were found in terms of pain threshold, pain tolerance, heart rate, and perceived decrease of pain. However, participants' expectation concerning the effectiveness of the intervention improved pain tolerance and affected perceived change of pain. In conclusion, the used PEMF device had no specific effect on acute ischemic muscle pain, while the contribution of the placebo effect was considerable.

Inhalation of a racemic mixture (R,S)-linalool by rats experiencing restraint stress alters neuropeptide and MHC class I gene expression in the hypothalamus

Some odorants have physiological and psychological effects on organisms. However, little is known about the effects of inhaling them, particularly on the central nervous system. Using DNA microarray analysis, we obtained gene expression profiles of the hypothalamus from restraint stressed rats exposed to racemic (R,S)-linalool. Hierarchical clustering across all probe sets showed that this inhalation of (R,S)-linalool influenced the expression levels of a wide range of genes in the hypothalamus. A comparison of transcription levels revealed that the inhalation of (R,S)-linalool restored the expression of 560 stress-induced probe sets to a normal status. Gene Ontology (GO) analysis showed that these genes were associated with synaptic transmission via neurotransmitters including anxiolytic neuropeptides such as oxytocin and neuropeptide Y. These genes also included several major histocompatibility complex (MHC) class I molecules necessary for neural development and plasticity. Moreover, Upstream Regulator Analysis predicted that the hormone prolactin would be activated by the inhalation of (R,S)-linalool under stress. Our results reveal some of the molecular mechanisms associated with odor inhalation in the hypothalamus in organisms under stress.