Diverse stimuli induce piloerection and yield varied autonomic responses in humans.

This research provides an in-depth exploration into the triggers and corresponding autonomic responses of piloerection, a phenomenon prevalent across various species. In non-human species, piloerection occurs in reaction to a variety of environmental changes, including social interactions and temperature shifts. However, its understanding in humans has been confined to emotional contexts. This is problematic because it reflects solely upon subjective experience rather than an objective response to the environment. Further, given our shared evolutionary paths, piloerection should function similarly in humans and other animals. I observed 1198 piloerection episodes from eight participants while simultaneously recording multiple autonomic and body temperature indices, finding that piloerection in humans can be elicited by thermal, tactile, and audio-visual stimuli with equal effectiveness. The data also revealed variations in cardiac reactivity measures: audio-visual piloerection was associated with greater sympathetic arousal, while tactile piloerection was linked to greater parasympathetic arousal. Despite prevailing notions of piloerection as a vestigial response in humans, it does respond to decreases in skin temperature and is associated with a rise in skin temperature during episodes. This research underscores that piloerection in humans is not purely vestigial, nor is it solely an affective response to emotional stimuli. Rather, it is best understood as a reflexive response to environmental changes, suggesting a shared functional similarity with other species.

Individuals lack the ability to accurately detect emotional piloerection.

Piloerection (e.g., goosebumps) is an essential thermoregulatory and social signaling mechanism in non-human animals. Although humans also experience piloerection-often being perceived as an indicator of profound emotional experiences-its comparatively less effective role in thermoregulation and communication might influence our capacity to monitor its occurrence. We present three studies (total N = 617) demonstrating participants' general inability to detect their own piloerection events and their lack of awareness that piloerection occurs with a similar frequency on multiple anatomical locations. Self-reported goosebumps were more frequent than observed piloerection. However, only 31.8% of self-reports coincided with observable piloerection, a bias unrelated to piloerection intensity, anatomical location, heart-rate variability, or interoceptive awareness. We also discovered a self-report bias for the forearm, contradicting the observation that piloerection occurs with equal frequency on multiple anatomical locations. Finally, there was low correspondence between self-reports of being "emotionally moved" and observed piloerection. These counterintuitive findings not only highlight a disconnect between an obvious physiological response and our capacity for self-monitoring, but they underscore a fascinating divergence between human and non-human species. Although piloerection is vital in non-human organisms, the connection between piloerection and psychological experience in humans may be less significant than previously assumed, possibly due to its diminished evolutionary relevance.

Late-onset seizures and epilepsy: Electroclinical features suggestive of autoimmune etiology.

Introduction: Late-onset epilepsy (LOE) has recently become a topic of intense research. Besides stroke, tumors, and dementia, autoimmune encephalitis (AE) has emerged as another possible cause of recurrent seizures in the elderly, and may account for a proportion of cases of LOE of unknown origin (LOEUO). This 24-h ambulatory electroencephalography (AEEG)-based study compared patients with LOEUO and AE to identify features suggestive of immune-mediated seizures in the elderly. Materials and methods: We retrospectively reviewed 232 AEEG examinations performed in patients over 55 years with ≥6-month follow-up, and selected 21 subjects with AE and 25 subjects with LOEUO. Clinical charts and AEEG recordings were carefully analyzed. Results: Twenty-five patients with LOEUO (12 women, mean age at onset 67.9 years) and 21 AE subjects (8 women, mean age at onset 65.7 years) were enrolled. High-frequency seizures were reported in 20/21 AE and 7/25 LOEUO cases (p < 0.00001). Focal aware seizures were more common in AE (14/21 vs. 6/25, p = 0.00058), whereas "isolated" focal-to-bilateral tonic-clonic seizures occurred in 5/25 patients with LOEUO only (p = 0.053). AE subjects reported ictal autonomic manifestations more frequently (p = 0.0033). Three-hundred-seventy and 24 seizures were recorded in 13/21 patients with AE and 3/25 patients with LOEUO, respectively (p = 0.0006). Interictal epileptiform discharges were observed in 70% of both groups, but their sleep activation was more common in AE (p = 0.06). Conclusion: Our study shows that high-frequency focal seizures with autonomic manifestations should raise the suspicion of AE in the elderly with new-onset seizures. It also highlights the relevant contribution of AEEG, which might reduce the diagnostic delay and provide useful clues to recognize AE.

The physiological study of emotional piloerection: A systematic review and guide for future research.

This paper provides an accessible review of the biological and psychological evidence to guide new and experienced researchers in the study of emotional piloerection in humans. A limited number of studies have attempted to examine the physiological and emotional correlates of piloerection in humans. However, no review has attempted to collate this evidence to guide the field as it moves forward. We first discuss the mechanisms and function of non-emotional and emotional piloerection in humans and animals. We discuss the biological foundations of piloerection as a means to understand the similarities and differences between emotional and non-emotional piloerection. We then present a systematic qualitative review (k = 24) in which we examine the physiological correlates of emotional piloerection. The analysis revealed that indices of sympathetic activation are abundant, suggesting emotional piloerection occurs with increased (phasic) skin conductance and heart rate. Measures of parasympathetic activation are lacking and no definite conclusions can be drawn. Additionally, several studies examined self-reported emotional correlates, and these correlates are discussed in light of several possible theoretical explanations for emotional piloerection. Finally, we provide an overview of the methodological possibilities available for the study of piloerection and we highlight some pressing questions researchers may wish to answer in future studies.

Pilomotor seizures in autoimmune limbic encephalitis: description of two GAD65 antibodies- related cases and literature review.

BACKGROUND: Ictal piloerection (IP) is a rare manifestation of focal epilepsy. Autoimmune limbic encephalitis (LE) and malignant brain tumours are the most frequent recognized aetiologies. METHODS: We selected all patients diagnosed with LE in our Institute from 2004 to 2020 and manifesting with IP. We performed a literature review on LE patients presenting IP. RESULTS: Of 15 patients diagnosed with LE (13.3%), two manifested IP as prominent ictal feature. One of them also had stiff-limb syndrome. Video-EEG documented ictal discharges from the right temporal regions with concomitant sympathetic skin response (SSR) recording. Antibody testing showed elevated serum and CSF titres of GAD65 antibodies (Ab), in both cases. Despite a combination of several anti-seizure medications and first- and second-line immunotherapy, they showed a poor clinical outcome after 2 and 9 years of follow-up, respectively. The literature review yielded 13 papers reporting 26 LE cases with IP. LGI1 Ab were the most frequently associated (73.1%) followed by VGKC-complex (7.7%), GAD65 (7.7%), NMDAr (3.8%), Ma2 (3.8%) and Hu (3.8%) Ab. Cases with LGI1 Ab showed a good response to immunotherapy. DISCUSSION AND CONCLUSION: The prevalence of IP in our LE cohort was of 13.3%, higher than expected. According to the literature review, most cases were associated with LGI1 Ab and showed a good response to immunotherapy. With the contribution of our cases, GAD65 emerged as the second most frequently detected Ab, showing a poor outcome. Our findings widen the spectrum of IP-associated Ab, with the respective prognostic implications.

Piloerection is not a reliable physiological correlate of awe.

In scientific and popular literature, piloerection (e.g. goosebumps) is often claimed to accompany the experience of awe, though this correlation has not been tested empirically. Using two pre-registered and independently collected samples (N = 210), we examined the objective physiological occurrence of piloerection in response to awe-inducing stimuli. Stimuli were selected to satisfy three descriptors of awe, including perceptual vastness, virtual reality, and expectancy-violating events. The stimuli reliably elicited self-reported awe to a great extent, in line with previous research. However, awe-inducing stimuli were not associated with the objective occurrence of piloerection. While participants self-reported high levels of goosebumps and "the chills," there was no physical evidence of this response. These results suggest that piloerection is not reliably connected to the experience of awe-at least using stimuli known to elicit awe in an experimental setting.

Volitional Control of Piloerection: Objective Evidence and Its Potential Utility in Neuroscience Research.

The volitional control of piloerection has been previously reported in a small subset of individuals. Although this ability may be useful to study the mechanism underlying piloerection, there is little existing research on this ability, neither objective evidence at a group-level, nor information about its stability under experimental constraints. The present study aimed to validate existing findings of voluntarily generated piloerection (VGP) and to examine its potential contribution to neuroscientific research based on objective evidence of this ability. In Study 1, to confirm the characteristics of VGP reported in previous studies and identify individuals with VGP capability, an online survey of VGP candidates was conducted. In Study 2, 18 VGP holders participated in a mail-based piloerection measurement experiment, and the nature of VGP was examined based on the objective data obtained by image-based analysis (GooseLab). Study 1 largely confirmed the characteristics of VGP reported in previous studies, and Study 2 demonstrated VGP at a group-level and provided information about the temporal characteristics of this ability, which supports the utility of VGP in neuroscientific research. For some participants, VGP appeared to be emotionally promoted, which suggests that VGP has some relationship with the emotional nature of involuntary piloerection. Although the studies did not tightly control the environment in which VGP was elicited, the findings nonetheless demonstrate the possible contribution of VGP to elucidating the mechanism of involuntary emotional piloerection and the neural basis of piloerection itself.

The use of infrared thermography to investigate emotions in common marmosets.

Measuring body surface temperature changes with infrared thermography has recently been put forward as a non-invasive alternative measure of physiological correlates of emotional reactions. In particular, the nasal region seems to be highly sensitive to emotional reactions. Several studies suggest that nasal temperature is negatively correlated with the level of arousal in humans and other primates, but some studies provide inconsistent results. Our goal was to establish the use of infrared thermography to quantify emotional reactions in common marmosets (Callithrix jacchus), with a focus on the nasal region. To do so we exposed 17 common marmosets to a set of positive, negative and control stimuli (positive: preferred food, playback of food calls; negative: playback of aggressive vocalizations, teasing; control: no stimulus). We compared nasal temperature before and after the stimuli and expected that highly aroused emotional states would lead to a drop in nasal temperature. To validate the thermography measure, we coded piloerection of the tail as an independent measure of arousal and expected a negative correlation between the two measures. Finally, we coded physical activity to exclude its potential confounding impact on nasal temperature. Our results show that all predictions were met: the animals showed a strong decrease in nasal temperature after the presentation of negative arousing stimuli (teasing, playback of aggressive vocalizations). Furthermore, these changes in nasal temperature were correlated with piloerection of the tail and could not be explained by changes in physical activity. In the positive and the control conditions, we found systematic sex differences: in males, the preferred food, the playbacks of food calls, as well as the control stimulus led to an increase in nasal temperature, whereas in females the temperature remained stable (preferred food, control) or decreased (playback of food calls). Based on naturalistic observations that document higher food motivation and competition among female marmosets, as well as stronger reactions to separation from group members in male marmosets, these sex differences corroborate a negative correlation between arousal and nasal temperature. Overall, our results support that measuring nasal temperature by infrared thermography is a promising method to quantify emotional arousal in common marmosets in a fully non-invasive and highly objective way.

Novel shampoo reduces hair shedding by contracting the arrector pili muscle via the trace amine-associated receptor.

BACKGROUND: Approximately 40% of women experience excessive hair shedding when washing their hair. Previously, we have demonstrated that a topically applied α1 adrenergic receptor agonist can be used to contract the arrector pili muscle of the follicular unit (ie, produce "goose bumps"), increasing the force required to pluck hair by as much as 400%. Subsequently, we reported a topical cosmetic solution containing an α1 adrenergic receptor agonist that reduced hair shedding during brushing by a maximum of 77%. AIMS: In this communication, we explore a novel mechanism to contract the arrector pili muscle. Trace amine-associated receptors (TAAR) have been shown to regulate smooth muscle tone in blood vessels, but have not been reported to be present in the skin. Here, we report on the anti-shedding efficacy of a shampoo containing a selective TAAR agonist, tyramine hydrochloride. METHODS: A single-blinded crossover study was designed to test the efficacy of the novel shampoo versus placebo in reducing hairs lost during brushing. RESULTS: In this study, the novel TAAR shampoo reduced hair shedding during brushing by 31% in a cohort of 24 women with a maximum reduction of 77%. CONCLUSIONS: A shampoo formulated with a selective TAAR agonist was demonstrated to contract the arrector pili muscle and reduce hair shedding subsequent to washing.

Ictal piloerection is associated with high-grade glioma and autoimmune encephalitis-Results from a systematic review.

PURPOSE: To comprehensively analyze ictal piloerection (IP) in a large number of subjects. METHODS: We performed a systematic review on case report studies of patients diagnosed with IP (1929-2017) with additional cases included from the Department of Neurology of University of Pécs, the National Institute of Clinical Neurosciences, and Odense University Hospital. Each included case was characterized regarding patient history, IP seizure characteristics, diagnostic work-up, and therapy. Comparative analyses were also carried out based on sex and pathology. RESULTS: Altogether, 109 cases were included. We observed a strong male predominance (p < 0.001). The mean age at onset of epilepsy was 39.5 ± 20.7 years (median: 38, IQR:24-57). The seizure onset zone was temporal (p < 0.001), and was lateralized to the ipsilateral hemisphere in unilateral localization (p = 0.001). The seizure was accompanied by cold shiver in 53%, and by other autonomic symptoms in 47% of cases. In 53% of patients, IP never progressed into complex partial or generalized tonic-clonic seizure; 16% of the patients reported occasional, and 31% regular generalization. Seizure frequency was higher among females (median:25/day, IQR:3-60) than among males (median:3/day, IQR:1-11) (p = 0.017). The two most common underlying pathologies were limbic encephalitis (23%) and astrocytoma (23%, among them 64% WHO III-IV astrocytoma). CONCLUSION: IP was particularly associated with autoimmune encephalitis and high-grade glioma, suggesting IP's particular clinical importance in directing diagnostic work-up.

The voluntary control of piloerection.

Autonomic nervous systems in the human body are named for their operation outside of conscious control. One rare exception is voluntarily generated piloerection (VGP)-the conscious ability to induce goosebumps-whose physiological study, to our knowledge, is confined to three single-individual case studies. Very little is known about the physiological nature and emotional correlates of this ability. The current manuscript assesses physiological, emotional, and personality phenomena associated with VGP in a sample of thirty-two individuals. Physiological descriptions obtained from the sample are consistent with previous reports, including stereotypical patterns of sensation and action. Most participants also reported that their VGP accompanies psychological states associated with affective states (e.g., awe) and experience (e.g., listening to music), and higher than typical openness to new experiences. These preliminary findings suggest that this rare and unusual physiological ability interacts with emotional and personality factors, and thus merits further study.

Styling without shedding: Novel topical formula reduces hair shedding by contracting the arrector pili muscle.

Approximately 40% of women experience excessive hair shedding during styling (e.g., hair brushing). Previously, we demonstrated that topically applied phenylephrine, a potent α1 adrenergic receptor agonist, can be used to contract the arrector pili muscle of the follicular unit; thus, increasing the force required to pluck hair and reducing shedding during brushing. While demonstrating efficacy, phenylephrine has several drawbacks when applied to the scalp, including the possibility cardiovascular events. We hypothesized that a high concentration of a weak α1 agonist would allow for: (a) rapid penetration through the stratum corneum eliciting a quick response; (b) a low probability of cardiac adverse events owing to the low receptor binding affinity; and (c) an efficacy of the weak α1 agonist similar to that of phenylephrine at the local site of application. Accordingly, we developed a novel topical solution, AB-102, containing a high concentration of a weak α1 agonist. Several studies were conducted to test the safety and efficacy of AB-102. In a dose escalating safety study, utilizing a wearable holter monitor, we observed no cardiac or hemodynamic adverse events. In addition, in a controlled efficacy study, AB-102 reduced the number of hairs shed during brushing by up to 77% (average of 38%).

The emotional power of poetry: neural circuitry, psychophysiology and compositional principles.

It is a common experience-and well established experimentally-that music can engage us emotionally in a compelling manner. The mechanisms underlying these experiences are receiving increasing scrutiny. However, the extent to which other domains of aesthetic experience can similarly elicit strong emotions is unknown. Using psychophysiology, neuroimaging and behavioral responses, we show that recited poetry can act as a powerful stimulus for eliciting peak emotional responses, including chills and objectively measurable goosebumps that engage the primary reward circuitry. Importantly, while these responses to poetry are largely analogous to those found for music, their neural underpinnings show important differences, specifically with regard to the crucial role of the nucleus accumbens. We also go beyond replicating previous music-related studies by showing that peak aesthetic pleasure can co-occur with physiological markers of negative affect. Finally, the distribution of chills across the trajectory of poems provides insight into compositional principles of poetry.

Tears Falling on Goosebumps: Co-occurrence of Emotional Lacrimation and Emotional Piloerection Indicates a Psychophysiological Climax in Emotional Arousal.

This psychophysiological study is the first to examine the relationship between emotional tears and emotional piloerection (i.e., goosebumps). Although both phenomena have been related to peak states of being moved, details about their temporal occurrence and the associated levels of physiological arousal have remained unknown. In our study, we used emotionally powerful film scenes that were self-selected by participants. Our findings show that even within peak moments of emotional arousal, a gradation of intensity is possible. The overlap of tears and goosebumps signifies a maximal climax within peak moments. On the side of the stimulus, we found that displays of prosocial behavior play a crucial role in the elicitation of tears and goosebumps. Finally, based on the results of a formal film analysis of the tears-eliciting clips provided by our participants, as compared to randomly extracted, equally long control clips from the same films, we show how the technical and artistic making of the clips was optimized for the display of social interaction and emotional expressions.

Evaluation of sub-chronic toxic effects of petroleum ether, a laboratory solvent in Sprague-Dawley rats.

BACKGROUND: In general, organic solvents are inhibiting many physiological enzymes and alter the behavioural functions, but the available scientific knowledge on laboratory solvent induced organ specific toxins are very limited. Hence, the present study was planned to determine the sub-chronic toxic effects of petroleum ether (boiling point 40-60°C), a laboratory solvent in Sprague-Dawley (SD) rats. MATERIALS AND METHODS: The SD rats were divided into three different groups viz., control, low exposure petroleum ether (250 mg/kg; i.p.) and high exposure petroleum ether (500 mg/kg; i.p.) administered group. The animals were exposed with petroleum ether once daily for 2 weeks. Prior to the experiment and end of the experiment animals behaviour, locomotor and memory levels were monitored. Before initiating the study animals were trained for 2 weeks for its learning process and its memory levels were evaluated. Body weight (BW) analysis, locomotor activity, anxiogenic effect (elevated plus maze) and learning and memory (Morris water navigation task) were monitored at regular intervals. On 14(th) day of the experiment, few ml of blood sample was collected from all the experimental animals for estimation of biochemical parameters. At the end of the experiment, all the animals were sacrificed, and brain, liver, heart, and kidney were collected for biochemical and histopathological analysis. RESULTS: In rats, petroleum ether significantly altered the behavioural functions; reduced the locomotor activity, grip strength, learning and memory process; inhibited the regular body weight growth and caused anxiogenic effects. Dose-dependent organ specific toxicity with petroleum ether treated group was observed in brain, heart, lung, liver, and kidney. Extrapyramidal effects that include piloerection and cannibalism were also observed with petroleum ether administered group. These results suggested that the petroleum ether showed a significant decrease in central nervous system (CNS) activity, and it has dose-dependent toxicity on all vital organs. CONCLUSION: The dose-dependent CNS and organ specific toxicity was observed with sub-chronic administration of petroleum ether in SD rats.

Alpha(1A)-adrenergic control of piloerection and palpebral fissure width in rats.

We determined the receptor subtypes of α1-adrenoceptor, which is involved in autonomic functions induced by methamphetamine (METH) in rats. An intraperitoneal injection of METH provoked the autonomic responses piloerection, eyelid retraction, and ejaculation. Pretreatment with prazosin, a nonselective α1-adrenoceptor antagonist, completely abolished the above METH-induced responses. Prazosin also provoked eyelid ptosis in saline controls. The effects of prazosin were mimicked only by a selective α1A-adrenoceptor antagonist, silodosin, not by selective α1B or α1D antagonists. These results suggest that α1A-adrenoceptor participates in the regulation of piloerection, palpebral fissure width, and ejaculation in rats.