Physiological Correlates Research Articles

The behavioral and physiological correlates of affective mood switching in premenstrual dysphoric disorder

Premenstrual dysphoric disorder (PMDD), a more severe manifestation of premenstrual syndrome (PMS), is characterized by emotional, behavioral, and physical symptoms that begin in the mid-to-late luteal phase of the menstrual cycle, when estradiol and progesterone levels precipitously decline, and remit after the onset of menses. Remotely monitoring physiologic variables associated with PMDD depression symptoms, such as heart rate variability (HRV), sleep, and physical activity, holds promise for developing an affective state prediction model. Switching into and out of depressive states is associated with an increased risk of suicide, and therefore, monitoring periods of affective switching may help mitigate risk. Management of other chronic health conditions, including cardiovascular disease and diabetes, has benefited from remote digital monitoring paradigms that enable patients and physicians to monitor symptoms in real-time and make behavioral and medication adjustments. PMDD is a chronic condition that may benefit from real-time, remote monitoring. However, clinical practice has not advanced to monitoring affective states in real-time. Identifying remote monitoring paradigms that can detect within-person affective state change may help facilitate later research on timely and efficacious interventions for individuals with PMDD. This narrative review synthesizes the current literature on behavioral and physiological correlates of PMDD suitable for remote monitoring during the menstrual cycle. The reliable measurement of heart rate variability (HRV), sleep, and physical activity, with existing wearable technology, suggests the potential of a remote monitoring paradigm in PMDD and other depressive disorders.

Social threat avoidance depends on action-outcome predictability

Avoiding threatening individuals is pivotal for adaptation to our social environment. Yet, it remains unclear whether social threat avoidance is subtended by goal-directed processes, in addition to stimulus-response associations. To test this, we manipulated outcome predictability during spontaneous approach/avoidance decisions from avatars displaying angry facial expressions. Across three virtual reality experiments, we showed that participants avoided more often when they could predict the outcome of their actions, indicating goal-directed processes. However, above-chance avoidance rate when facing unpredictable outcomes suggested that stimulus-response associations also played a role. We identified two latent classes of participants: the “goal-directed class” showed above-chance avoidance only in the predictable condition, while the “stimulus-response class” showed no credible difference between conditions but had a higher overall avoidance rate. The goal-directed class exhibited greater cardiac deceleration in the predictable condition, associated with better value integration in decision-making. Computationally, this class had an increased drift-rate in the predictable condition, reflecting increased value estimation of threat avoidance. In contrast, the stimulus-response class showed higher responsiveness to threat, indicated by increased drift-rate for avoidance and increased muscular activity at response time. These results support the central role of goal-directed processes in social threat avoidance and reveal its physiological and computational correlates.

Evaluating Typing Performance in Different Mixed Reality Manifestations using Physiological Features

Mixed reality enables users to immerse themselves in high-workload interaction spaces like office work scenarios. We envision physiologically adaptive systems that can move users into different mixed reality manifestations, to improve their focus on the primary task. However, it is unclear which manifestation is most conducive for high productivity and engagement. In this work, we evaluate whether physiological indicators for engagement can be discriminated for different manifestations. For this, we engaged participants in a typing task in three different mixed reality manifestations (augmented reality, augmented virtuality, virtual reality) and monitored physiological correlates (EEG, ECG, and eye tracking) of users' engagement and workload. We found that users achieved best typing performances in augmented reality and augmented virtuality. At the same time, physiological engagement peaked in augmented virtuality, while workload decreased. We conclude that augmented virtuality strikes a good balance between the different manifestations, as it facilitates displaying the physical keyboard for improved typing performance and, at the same time, allows one to block out the real world, removing many real-world distractors.

Exposure to fungal infection decreases eye size in the zooplankton, Daphnia

Abstract Immune responses can be energetically expensive and subject to trade-offs. Prior work on the freshwater zooplankton, Ceriodaphnia cornuta, demonstrated an association between eye size and infection, leading to questions about whether investment in eyes trades off against investment in immunity. We used the crustacean host, Daphnia dentifera, and its fungal parasite, Metschnikowia bicuspidata, to investigate the relationships between eye size, parasite resistance and infection. In the field, we found a negative correlation between size-corrected eye area (SCEA) and Metschnikowia infection, suggesting that either SCEA decreases infection (thereby indicating resistance) or that infection decreases SCEA. Controlled laboratory experiments reinforced the latter result: exposure to the fungal parasite decreased a host’s SCEA, regardless of the parasite dose or host genotype. We also uncovered significant plasticity in this trait—both host age and resource level increased SCEA. Identifying causality in physiological correlations is challenging. Our results suggest that negative associations between parasitism and energetically-expensive traits can arise through plasticity.

Multimodal physiological correlates of dyspnea ratings during breath-holding in healthy humans.

Dyspnea is associated with fear and intense suffering and is often assessed using visual analog scales (VAS) or numerical rating scales (NRS). However, the physiological correlates of such ratings are not well known. Using the voluntary breath-holding model of induced dyspnea, we studied healthy volunteers to investigate the temporal relationship between dyspnea, the neural drive to breathe assessed in terms of involuntary thoracoabdominal movements (ITMs) and neurovegetative responses. Twenty-three participants (10 men; median [interquartile range] age 21 [20-21]) performed three consecutive breath-holds with the continuous assessment of dyspnea (urge-to-breathe) using a 10cm VAS, thoracic and abdominal circumferences measured with piezoelectric belt-mounted transducers, heart rate and heart rate variability (HRV), and galvanic skin response (GSR). Urge-to-breathe VAS at the onset of ITMs (gasping point) was identified visually or algorithmically. Urge-to-breathe VAS at the end of the breath-hold was 9.7 [8.6-10] cm. Total breath-hold duration was 93 [69-130]s. Urge-to-breathe VAS, ITM, heart rate, HRV, and GSR significantly increased during breath-hold. Urge-to-breathe VAS correlated with the magnitude of the thoracic and abdominal movements (rho = 0.51 and rho = 0.59, respectively, p < 0.001). The urge-to-breathe ratings corresponding with ITM onset were 3.0 [2.0-4.7] cm and 3.0 [1.0-4.0] cm for visual and algorithmic detection, respectively (p = 0.782). An urge-to-breathe VAS of 3cm (30% of full scale on a 10cm VAS) corresponds to a physiological turning point during the physiological response to voluntary breath-holding in healthy humans.

Correlates and predictors of symptom severity over time in people under investigation for postural orthostatic tachycardia syndrome (POTS).

Postural Orthostatic Tachycardia Syndrome (POTS) is a poorly understood chronic disorder characterised by an unexplained excessive increase in heartbeat upon standing. The aim of this study was to investigate psychosocial and physiological correlates and predictors of symptom severity over time in patients presenting with POTS-like symptoms. Longitudinal cohort study of patients under investigation for POTS ( n = 149). Patients completed questionnaires at one month pre-clinic appointment and 6 months later. Diagnosis, blood pressure (BP) and heart rate (HR) measures were collected from medical records. Data were analysed using hierarchical linear multiple regression. Orthostatic and small fibre neuropathy (SFN) symptoms remained stable over time and were significantly correlated with distress, cardiac anxiety, threatening views of the illness, and cognitive-behavioural responses to symptoms, but not with emotional reactivity or social support. Baseline psychosocial factors collectively explained 48% (F = 5.37, p < .001) of the variance in orthostatic symptoms, and 35% (F = 3.49, p < .001) of the variance of SFN symptoms at baseline, but a non-significant amount of variance in symptoms at 6 months when controlling for baseline symptoms. Haemodynamic measures explained a significant 4% (F = 3.37, p = .026) of variance of orthostatic symptoms at 6 months. Symptom burden in patients with suspected POTS remained high over 6 months. Psychosocial factors explained a large amount of the variance in symptoms at baseline. As symptoms did not change/improve over time, baseline symptoms accounted for most of the variance in symptoms at 6 months. An integrated approach addressing psychosocial factors alongside medical treatments may promote adjustment to the condition and lessen symptom burden for this group.

Links between ethnic discrimination, mental health, protective factors, and hair cortisol concentrations in asylum seekers living in Germany

ABSTRACT Objective: Asylum seekers often experience ethnic discrimination on the flight or in the host country, which may be associated with chronic stress and impaired mental health. Dysregulation of the hypothalamic–pituitary–adrenal axis, a known physiological correlate of chronic stress, can be assessed using hair cortisol concentrations (HCC). The present study aimed to investigate how different forms of perceived ethnic discrimination are associated with mental health outcomes, HCC, and protective factors in asylum seekers living in Germany. Methods: Somatic symptoms (PHQ-15), symptoms of posttraumatic stress (PDS), depressive symptoms (PHQ-9), different forms of ethnic discrimination (active harm, passive harm, institutional discrimination), and protective factors (in-group identification, social support) were assessed cross-sectionally in 144 asylum seekers (average age 32 years, average duration of stay in Germany nine months; 67% men). HCC were obtained from 68 participants. Multiple regression analyses were conducted and social support and in-group identification were tested as potential moderators. Results: Active ethnic discrimination was positively associated with all assessed mental health outcomes, and all forms of ethnic discrimination positively correlated with depressive symptoms. Ethnic discrimination was not associated with HCC. When controlling for other possible influences (e.g. age, gender, traumatic events), passive harm was negatively associated with depressive symptoms (β = −0.17, p = .033) and active harm was positively associated (β = 0.28, p = .022) with somatic symptoms. After the inclusion of the protective factors, the associations were no longer significant. Lower social support was associated with higher depressive symptoms (β = −0.35, p < .001), posttraumatic stress (β = −0.77, p < .001), and somatic symptoms (β = −0.32, p < .001), but did not moderate the associations between ethnic discrimination and the mental health outcomes. Conclusions: Perceived ethnic discrimination may negatively influence asylum seekers’ mental health but does not seem to be associated with HCC. Social support was associated with psychological symptom severity, but did not buffer the effects of ethnic discrimination on mental health.

Sex differences in physiological correlates of affectively driven decision-making behavior in adult ADHD

BackgroundSex differences in the symptomatology of adults with attention-deficit/hyperactivity disorder (ADHD) have often been overlooked when studying behavioral abnormalities. However, it is known that women exhibit considerably more stronger symptoms related to emotional competence than men. Since affective functions significantly influence the processing of risky decision-making and risk-engagement, we assume that risky behavior in ADHD is affected by sex differences. Therefore, we specifically investigated sex-specific effects on the interaction between emotionally induced changes in physiology and behavioral performance on a decision-making task.MethodsSkin conductance responses of twenty-nine adults with ADHD (n = 16 male; n = 13 female) and thirty-three adults in the control group (n = 14 male; n = 19 female) were recorded during the performance in a modified version of the Balloon Analogue Risk Task (BART). Additional questionnaires were used to reveal insights in the self-assessment of emotional competence, risk perception, and feedback sensitivity. Emotional arousal and decision-making behavior were analyzed using linear mixed-effects models.ResultsResults showed different effects of sex on risk behaviors in controls and ADHD. In contrast to healthy controls, female adults with ADHD showed a significantly greater risk engagement in the BART compared to males with ADHD. This contrary sex relation was not observed in skin conductance responses and revealed a significantly different sex-dependent correlation of body response and behavioral task performance in ADHD. Comparisons with results from self-assessments furthermore indicate a reduced behavioral self-perception in women with ADHD, but not in men.ConclusionIn summary, we found an altered interaction between physiological activity and risky behavior in women with ADHD. Thus, the present study indicates a reduced sensitivity towards the own bodily responses in women with ADHD, which could consequently cause increased risky DM behavior in daily life. The current results suggest that more consideration needs to be given to sex-specific effects on physiological processes and behavior in adults with ADHD.

BLUE SABINO: Development of a BiLateral Upper-Limb Exoskeleton for Simultaneous Assessment of Biomechanical and Neuromuscular Output

Arm and hand function play a critical role in the successful completion of everyday tasks. Lost function due to neurological impairment impacts millions of lives worldwide. Despite improvements in the ability to assess and rehabilitate arm deficits, knowledge about underlying sources of impairment and related sequela remains limited. The comprehensive assessment of function requires the measurement of both biomechanics and neuromuscular contributors to performance during the completion of tasks that often use multiple joints and span three-dimensional workspaces. To our knowledge, the complexity of movement and diversity of measures required are beyond the capabilities of existing assessment systems. To bridge current gaps in assessment capability, a new exoskeleton instrument is developed with comprehensive bilateral assessment in mind. The development of the BiLateral Upper-limb Exoskeleton for Simultaneous Assessment of Biomechanical and Neuromuscular Output (BLUE SABINO) expands on prior iterations toward full-arm assessment during reach-and-grasp tasks through the development of a dual-arm and dual-hand system, with 9 active degrees of freedom per arm and 12 degrees of freedom (six active, six passive) per hand. Joints are powered by electric motors driven by a real-time control system with input from force and force/torque sensors located at all attachment points between the user and exoskeleton. Biosignals from electromyography and electroencephalography can be simultaneously measured to provide insight into neurological performance during unimanual or bimanual tasks involving arm reach and grasp. Design trade-offs achieve near-human performance in exoskeleton speed and strength, with positional measurement at the wrist having an error of less than 2 mm and supporting a range of motion approximately equivalent to the 50th-percentile human. The system adjustability in seat height, shoulder width, arm length, and orthosis width accommodate subjects from approximately the 5th-percentile female to the 95th-percentile male. Integration between precision actuation, human–robot-interaction force-torque sensing, and biosignal acquisition systems successfully provide the simultaneous measurement of human movement and neurological function. The bilateral design enables use with left- or right-side impairments as well as intra-subject performance comparisons. With the resulting instrument, the authors plan to investigate underlying neural and physiological correlates of arm function, impairment, learning, and recovery.

Ellagic acid improves the symptoms of early-onset Alzheimer's disease: Behavioral and physiological correlates

Oryza sativa is a globally recognized staple food, rich in essential phyto-phenolic compounds such as γ-Oryzanol (OZ), Ferulic acid (FA), and Ellagic acid (EA). These phytochemicals are known for their potential to beneficially modulate molecular biochemistry. The present investigation aimed to evaluate the neuroprotective and cognitive enhancement effects of Oryza sativa phyto-phenolics in a model of early-onset Alzheimer's disease (EOAD) induced by Aβ (1-42) in animals. In-silico studies suggested that FA, OZ, and EA have target specificity for Aβ, with EA being further selected based on its potent in-vitro Aβ anti-aggregatory effects for exploring neurodegenerative conditions. The in-vivo experiments demonstrated that EA exerts therapeutic effects in Aβ-induced EOAD, modulating both biochemical and behavioral outcomes. EA treatment at two dose levels, EA70 and EA140 (70 μM and 140 μM, respectively, administered i.c.v.), significantly counteracted Aβ aggregation and modulated the Ca2⁺/Calpain/GSK-3β/CDK5 signaling pathways, exhibiting anti-tauopathy effects. Additionally, EA was shown to exert anti-inflammatory effects by preventing astroglial activation, modulating FAIM-L expression, and protecting against TNF-α-induced apoptotic signals. Moreover, the neuromodulatory effects of EA were attributed to the regulation of CREB levels, Dnm-1 expression, and synaptophysin levels, thereby enhancing LTP and synaptic plasticity. EA also induced beneficial cytological and behavioral changes, improving both long-term and short-term spatial memory as well as associative learning behavior in the animal model, which underscores its cognitive enhancement properties.

Using Wearables to Study Biopsychosocial Dynamics in Couples Who Cope With a Chronic Health Condition: Ambulatory Assessment Study.

Technology has become an integral part of our everyday life, and its use to manage and study health is no exception. Romantic partners play a critical role in managing chronic health conditions as they tend to be a primary source of support. This study tests the feasibility of using commercial wearables to monitor couples' unique way of communicating and supporting each other and documents the physiological correlates of interpersonal dynamics (ie, heart rate linkage). We analyzed 617 audio recordings of 5-minute duration (384 with concurrent heart rate data) and 527 brief self-reports collected from 11 couples in which 1 partner had type II diabetes during the course of their typical daily lives. Audio data were coded by trained raters for social support. The extent to which heart rate fluctuations were linked among couples was quantified using cross-correlations. Random-intercept multilevel models explored whether cross-correlations might differ by social contexts and exchanges. Sixty percent of audio recordings captured speech between partners and partners reported personal contact with each other in 75% of self-reports. Based on the coding, social support was found in 6% of recordings, whereas at least 1 partner self-reported social support about half the time (53%). Couples, on average, showed small to moderate interconnections in their heart rate fluctuations (r=0.04-0.22). Couples also varied in the extent to which there was lagged linkage, that is, meaning that changes in one partner's heart rate tended to precede changes in the other partner's heart rate. Exploratory analyses showed that heart rate linkage was stronger (1) in rater-coded partner conversations (vs moments of no rater-coded partner conversations: rdiff=0.13; P=.03), (2) when partners self-reported interpersonal contact (vs moments of no self-reported interpersonal contact: rdiff=0.20; P<.001), and (3) when partners self-reported social support exchanges (vs moments of no self-reported social support exchange: rdiff=0.15; P=.004). Our study provides initial evidence for the utility of using wearables to collect biopsychosocial data in couples managing a chronic health condition in daily life. Specifically, heart rate linkage might play a role in fostering chronic disease management as a couple. Insights from collecting such data could inform future technology interventions to promote healthy lifestyle engagement and adaptive chronic disease management. RR2-10.2196/13685.

The effect of group size on sleep in a neotropical bat, Artibeus jamaicensis.

Sleep is associated with many costs, but is also important to survival, with a lack of sleep impairing cognitive function and increasing mortality. Sleeping in groups could alleviate sleep-associated costs,or could introduce new costs if social sleeping disrupts sleep. Working with the Jamaican fruit bat (Artibeus jamaicensis), we aimed to: (1) describe sleep architecture, (2) assess how sleeping in groups affects sleep, and (3) quantify total sleep time and identify rapid eye movement (REM)sleep using behavioral indicators that complement physiological evidence of sleep. Twenty-five adult bats were captured in Panama and recorded sleeping in an artificial roost enclosure. Three bats were fitted with an electromyograph and accelerometer and video recorded sleeping alone in controlled laboratory settings. The remaining 22 bats were assigned to differing social configurations (alone, dyad, triad, and tetrad) and video recorded sleeping in an outdoor flight cage. We found that sleep was highly variable among individuals (ranging from 2 h 53 min to 9 h 39 min over a 12-h period). Although we did not detect statistically significant effects and our sample size was limited, preliminary trends suggest that male bats may sleep longer than females, and individuals sleeping in groups may sleep longer than individuals sleeping alone. We also found a high correspondence between total sleep time quantified visually and quantified using actigraphy (with a 2-min immobility threshold) and identified physiological correlates of behaviorally-defined REM. These results serve as a starting point for future work on the ecology and evolution of sleep in bats and other wild mammals.

Predictors of irritability in pediatric autistic populations: a scoping review

IntroductionAutism is characterized by social communication differences and repetitive behaviors, affecting 1%–2% of children. Irritability is a disabling condition affecting 19%–80% of autistic children. While extensive research has focused on interventions to reduce irritability symptoms, the underlying correlates remain poorly understood. To address this, we conducted a scoping review of the literature examining factors contributing to irritability in pediatric autistic populations.MethodsA literature search of Embase, MEDLINE, PubMed, PsycINFO, and Web of Science was conducted in addition to manually retrieved papers from Google Scholar. Studies underwent title and abstract screening by one reviewer and full-text screening by two reviewers; disagreements were resolved through deliberation. The remaining studies underwent data extraction. The review was conducted using the PRISMA-ScR checklist.ResultsThe search yielded 48 studies meeting the inclusion criteria. Correlates of irritability were categorized into eight themes: demographics/environmental, autism features, mental health, language, cognition, and function, neurobiological, physical health, physiological, and multidimensional factors. Findings revealed mixed associations with demographic factors, consistent positive associations with sensory differences and mental health symptoms, and varying associations with cognitive abilities and physical health factors. Neurobiological and physiological correlates were less explored.ConclusionThis review revealed a significant gap in understanding sociodemographic, phenotypic, and neurobiological and physiological correlates of irritability in autism. There was also a significant gap in understanding the multi-dimensional irritability correlates. Positive associations between irritability and sensory differences and mental health symptoms suggest potential avenues for investigation of non-medication interventions.

Conceptualizing disparities and differences in the psychobiology of traumatic stress.

Understanding biological pathways that mediate trauma-related psychopathology is a major goal for traumatic stress studies. There is growing interest in studying differences in neural, physiological, and behavioral correlates of traumatic stress across demographic groups (e.g., sex/gender, race/ethnicity). However, challenges remain in how to appropriately conceptualize the source, mechanisms, and practical utility of between-group variation. The present brief conceptual review discusses ethnicity, race, and sex/gender-related variability relevant to understanding the psychobiology of traumatic stress in the context of traumatic stress studies. We discuss recent evidence related to socioenvironmental influences on ethnoracial variability in the brain and behavior relevant to traumatic stress, as well as sex/gender associations in neurophysiology that may contribute to the development of adverse posttraumatic sequelae. We further synthesize these findings by discussing intersectional influences of sex/gender- and race/ethnicity-related factors on trauma-related physical and mental health outcomes. The present review provides an important foundation for future research on disparities and individual differences in traumatic stress to move the field toward more effective assessment and treatment approaches.

Fear of cancer recurrence and change in hair cortisol concentrations in partners of breast cancer survivors.

Partners of breast cancer (BC) survivors report high rates of psychological distress including fear of cancer recurrence (FCR). Research suggests that partners may have poorer physical health outcomes than the general population, but little research has examined the physiological biomarkers by which distress may impact partner health outcomes. The current study examined the associations between FCR and changes in hair cortisol among BC partners. Male partners (N = 73) of early-stage BC survivors provided hair samples during two visits, one after completion of survivors' adjuvant treatment (T1) and again 6 months later (T2). Two subscales from the Fear of Cancer Recurrence Inventory and one subscale from the Concerns about Recurrence Scale comprised a latent FCR factor at T1. A latent change score model was used to examine change in cortisol as a function of FCR. Partners were on average 59.65 years of age (SD = 10.53) and non-Hispanic White (83%). Latent FCR at T1 was positively associated (b = 0.08, SE = 0.03, p = .004, standardized β = .45) with change in latent hair cortisol from T1 to T2. Results indicated that greater FCR was associated with increases in hair cortisol in the months following adjuvant treatment. This is one of the first studies to examine the physiological correlates of FCR that may impact health outcomes in BC partners. Findings highlight the need for further research into the relationship between FCR and its physiological consequences. Interventions to address partner FCR are needed and may aid in improving downstream physical health outcomes.

Context-dependent effects of thermal acclimation on physiological correlates of animal personality in Asiatic toads.

Persistent individual variation in behaviour, or 'personality', is a widespread phenomenon in animals, and understanding the evolution of animal personality is a key task of current biology. Natural selection has been proposed to promote the integration of personality with animal 'intrinsic states', such as metabolic or endocrine traits, and this integration varies with ecological conditions. However, these external ecological modulatory effects have rarely been examined. Here, we investigate the effects of thermal acclimation on between-individual covariations between physiology and behaviour in Asiatic toads (Bufo gargarizans) along an altitudinal gradient. Our results reveal that the thermal modulatory effects on the covariations depend on the altitudinal population. Specifically, at low altitudes, between-individual covariations are highly plastic, with risk-taking behaviour covarying with baseline glucocorticoids (GCs) under warm acclimation, but risk-taking and exploration behaviour covarying with resting metabolic rate (RMR) under cold acclimation. In contrast, between-individual covariations are relatively fixed at high altitudes, with risk-taking behaviour consistently covarying with baseline GCs. Furthermore, at low altitudes, changes in covariations between RMR and personality are associated with adjustment of energy management models. Evidently, animal physiological states that determine or covary with personality can adapt according to the seasonal thermal environment and the thermal evolutionary background of populations. Our findings highlight the importance of a multi-system physiological approach to understand the evolution of animal personality.

IAVRS-International Affective Virtual Reality System: Psychometric Assessment of 360° Images by Using Psychophysiological Data.

Virtual Reality is an effective technique for eliciting emotions. It provides immersive and ecologically valid emotional experiences while maintaining experimental control. Recently, novel VR forms like 360° videos have been used successfully for emotion elicitation. Some preliminary databases of 360° videos for emotion elicitation have been proposed, but they tapped mainly into an emotional dimensional approach and did not include a concurrent physiological assessment of an emotional profile. This study expands on these databases by combining dimensional and discrete approaches to validate a new set of 360° emotion-inducing images. Twenty-six participants viewed 46 immersive images, and their emotional reactions were measured using self-reporting, psychophysiological signals, and eye tracking. The IAVRS database can successfully elicit a wide range of emotional responses, including both positive and negative valence, as well as different levels of arousal. Results reveal an important correspondence between the discrete and dimensional models of emotions. Furthermore, the images that exhibit convergence between the dimensional and discrete emotional models are particularly impactful regarding arousal and valence values. The IAVRS database provides insights into potential relationships between physiological parameters and emotional responses. This preliminary investigation highlights the complexity of emotional elicitation processes and their physiological correlates, suggesting the need for further research to deepen our understanding.

Contactless vital signs monitoring in macaques using a mm-wave FMCW radar

Heart rate (HR) and respiration rate (RR) play an important role in the study of complex behaviors and their physiological correlations in non-human primates (NHPs). However, collecting HR and RR information is often challenging, involving either invasive implants or tedious behavioral training, and there are currently few established simple and non-invasive techniques for HR and RR measurement in NHPs owing to their stress response or indocility. In this study, we employed a frequency-modulated continuous wave (FMCW) radar to design a novel contactless HR and RR monitoring system. The designed system can estimate HR and RR in real time by placing the FMCW radar on the cage and facing the chest of both awake and anesthetized macaques, the NHP investigated in this study. Experimental results show that the proposed method outperforms existing methods, with averaged absolute errors between the reference monitor and radar estimates of 0.77 beats per minute (bpm) and 1.29 respirations per minute (rpm) for HR and RR, respectively. In summary, we believe that the proposed non-invasive and contactless estimation method could be generalized as a HR and RR monitoring tool for NHPs. Furthermore, after modifying the radar signal-processing algorithms, it also shows promise for applications in other experimental animals for animal welfare, behavioral, neurological, and ethological research.

Interplay of hippocampal long-term potentiation and long-term depression in enabling memory representations.

Hippocampal long-term potentiation (LTP) and long-term depression (LTD) are Hebbian forms of synaptic plasticity that are widely believed to comprise the physiological correlates of associative learning. They comprise a persistent, input-specific increase or decrease, respectively, in synaptic efficacy that, in rodents, can be followed for days and weeks in vivo. Persistent (>24 h) LTP and LTD exhibit distinct frequency-dependencies and molecular profiles in the hippocampal subfields. Moreover, causal and genetic studies in behaving rodents indicate that both LTP and LTD fulfil specific and complementary roles in the acquisition and retention of spatial memory. LTP is likely to be responsible for the generation of a record of spatial experience, which may serve as an associative schema that can be re-used to expedite or facilitate subsequent learning. In contrast, LTD may enable modification and dynamic updating of this representation, such that detailed spatial content information is included and the schema is rendered unique and distinguishable from other similar representations. Together, LTP and LTD engage in a dynamic interplay that supports the generation of complex associative memories that are resistant to generalization. This article is part of a discussion meeting issue 'Long-term potentiation: 50 years on'.

Physiology of Risk-Taking and Risk Management in Realistic Decision-Making Scenarios.

Decisions under risk are a particular case of decisional skills taking place in complex and mostly unpredictable situations, where affective connotation of deciding is highly relevant. We aimed at investigating decisional processes under risk by outlining individual risk-taking (RT) and risk management (RM) attitudes via realistic decision-making and, in keeping with the risk-as-feeling hypothesis, at exploring implicit physiological correlates of such processes. 35 participants were presented with realistic situations where they had to make decisions by choosing between alternatives connoted by different levels of riskiness. Concurrently, autonomic physiological activation (cardiovascular and electrodermal activity) was recorded. Data analysis highlighted that: (i) participants showed higher propensity towards risk management than risk-taking; (ii) the propensity towards both risk taking and risk management was significantly determined by physiological markers of autonomic activity; and (iii) risk taking and risk management indices showed associations with different autonomic measures, respectively heart rate and skin conductance metrics.