Allostasis: a model of predictive regulation

Circadian rhythms and the HPA axis: A systems view

The circadian timing system comprises a network of time-keeping clocks distributed across a living host whose responsibility is to allocate resources and distribute functions temporally to optimize fitness. The molecular structures generating these rhythms have evolved to accommodate the rotation of the earth in an attempt to primarily match the light/dark periods during the 24-hr day. To maintain synchrony of timing across and within tissues, information from the central clock, located in the suprachiasmatic nucleus, is conveyed using systemic signals. Leading among those signals are endocrine hormones, and while the hypothalamic-pituitary-adrenal axis through the release of glucocorticoids is a major pacesetter. Interestingly, the fundamental units at the molecular and physiological scales that generate local and systemic signals share critical structural properties. These properties enable time-keeping systems to generate rhythmic signals and allow them to adopt specific properties as they interact with each other and the external environment. The purpose of this review is to provide a broad overview of these structures, discuss their functional characteristics, and describe some of their fundamental properties as these related to health and disease. This article is categorized under: Immune System Diseases > Computational Models Immune System Diseases > Biomedical Engineering.

Home Hazards With Fear of Falling: Findings From the Baseline Study of the Malaysian Elders Longitudinal Research (MELoR)

Background: Fear of falling (FoF) is a common issue among older people, impacting on psychological health, functional performance and mortality. Many factors associated with fear of falling have been investigated but little is known about the role of home hazards. Home hazards can be due to unsafe environmental and functional features. This study is aims to evaluate the association between home hazards with fear of falling among community-dwelling individuals aged 55 years and over. Methods: Baseline data with 1,489 older individuals from the Malaysian Elders Longitudinal Research (MELoR) study were analyzed. Home visits for interview and observations in the home were conducted with the participants. FoF was established with a single-item question and home hazards with the Home Falls and Accidents Screening Tool (HOME FAST). Results: The majority (76.4%) of older participants experienced FoF. The history of falls was not associated with FoF (p = 0.868), but FoF was associated with participants limiting their daily activities (p < 0.001). Home hazards were less likely (p = 0.023) and functional issues were more likely (p < 0.001) to be associated with a high degree of FoF. However, both home hazards domains were not associated with activity restriction due to FoF. Conclusions: Education about home hazards from the perspective of person-environment interaction may encourage home hazards management and reduce FoF which should be evaluated in future studies.

Role of angiotensin receptors in the medial amygdaloid nucleus in autonomic, baroreflex and cardiovascular changes evoked by chronic stress in rats

This study investigated the role of AT₁ , AT₂ and Mas angiotensinergic receptors within the MeA in autonomic, cardiovascular and baroreflex changes evoked by a 10-day (1  hr daily) repeated restraint stress (RRS) protocol. Analysis of cardiovascular function after the end of the RRS protocol indicated increased values of arterial pressure, without heart rate changes. Arterial pressure increase was not affected by acute MeA treatment after the RRS with either the selective AT₁ receptor antagonist losartan, the selective AT₂ receptor antagonist PD123319 or the selective Mas receptor antagonist A-779. Analysis of heart rate variability indicated that RRS increased the sympathetic tone to the heart, which was inhibited by MeA treatment with either losartan, PD123319 or A-779. Baroreflex function assessed using the pharmacological approach via intravenous infusion of vasoactive agents revealed a facilitation of tachycardia evoked by blood pressure decrease in chronically stressed animals, which was inhibited by MeA treatment with losartan. Conversely, baroreflex responses during spontaneous fluctuations of blood pressure were impaired by RRS, and this effect was not affected by injection of the angiotensinergic receptor antagonists into the MeA. Altogether, the data reported in the present study suggest an involvement of both angiotensinergic receptors present in the MeA in autonomic imbalance evoked by RRS, as well as an involvement of MeA AT₁ receptor in the enhanced baroreflex responses during full range of blood pressure changes. Results also indicate that RRS-evoked increase in arterial pressure and impairment of baroreflex responses during spontaneous variations of arterial pressure are independent of MeA angiotensinergic receptors.

The physical frailty syndrome as a transition from homeostatic symphony to cacophony

Frailty in aging marks a state of decreased reserves resulting in increased vulnerability to adverse outcomes when exposed to stressors. This Perspective synthesizes the evidence on the aging-related pathophysiology underpinning the clinical presentation of physical frailty as a phenotype of a clinical syndrome that is distinct from the cumulative-deficit-based frailty index. We focus on integrating the converging evidence on the conceptualization of physical frailty as a state, largely independent of chronic diseases, that emerges when the dysregulation of multiple interconnected physiological and biological systems crosses a threshold to critical dysfunction, severely compromising homeostasis. Our exegesis posits that the physiology underlying frailty is a critically dysregulated complex dynamical system. This conceptual framework implies that interventions such as physical activity that have multisystem effects are more promising to remedy frailty than interventions targeted at replenishing single systems. We then consider how this framework can drive future research to further understanding, prevention and treatment of frailty, which will likely preserve health and resilience in aging populations.

Functions of Interoception: From Energy Regulation to Experience of the Self

We review recent work on the functions of interoceptive processing, by which the nervous system anticipates, senses, and integrates signals originating from the body. We focus on several exemplar functions of interoception, including energy regulation (ingestion and excretion), memory, affective and emotional experience, and the psychological sense of self. We emphasize two themes across these functions. First, the anatomy of interoceptive afferents makes it difficult to manipulate or directly measure interoceptive signaling in humans. Second, recent evidence shows that multimodal integration occurs across interoceptive modalities and between interoceptive and exteroceptive modalities. Whereas exteroceptive multimodal integration has been studied relatively extensively, fundamental questions remain regarding multimodal integration that involves interoceptive modalities. Future empirical work is required to better understand how and where multimodal interoceptive integration occurs.

In the Flow of Life: Capturing Affective Socializing Dynamics Using a Wearable Sensor and Intensive Daily Diaries

Interpersonal socializing is important to many sociological outcomes, but assessing the affective dynamics within interactional contexts is extremely challenging methodologically. As a first step toward capturing socializing and affective outcomes concurrently, this pilot study (n = 118) combines intensive daily surveys with a wearable sensor that tracked affective arousal. This approach allowed the operationalization of affect along its two primary dimensions, valence and arousal, which were then linked to periods socializing with a romantic partner, a best friend, and/or a group of friends. Although socializing predicted positive and negative affective valence concurrently in time, only socializing with groups of friends consistently predicted increased affective arousal. Findings for romantic partners and/or socializing with a close friend suggest that low arousal "downtime" with close intimates may also provide important social functions. This work demonstrates a new biosignaling approach to affective dynamics broadly relevant to emotion-related sociological research.

The 4R's Framework of Nutritional Strategies for Post-Exercise Recovery: A Review with Emphasis on New Generation of Carbohydrates

Post-exercise recovery is a broad term that refers to the restoration of training capacity. After training or competition, there is fatigue accumulation and a reduction in sports performance. In the hours and days following training, the body recovers and performance is expected to return to normal or improve. ScienceDirect, PubMed/MEDLINE, and Google Scholar databases were reviewed to identify studies and position declarations examining the relationship between nutrition and sports recovery. As an evidence-based framework, a 4R’s approach to optimizing post-exercise recovery was identified: (i) Rehydration—a fundamental process that will depend on the athlete, environment and sports event; (ii) Refuel—the consumption of carbohydrates is not only important to replenish the glycogen reserves but also to contribute to the energy requirements for the immune system and tissue reparation. Several bioengineered carbohydrates were discussed but further research is needed; (iii) Repair—post-exercise ingestion of high-quality protein and creatine monohydrate benefit the tissue growth and repair; and (iv) Rest—pre-sleep nutrition has a restorative effect that facilitates the recovery of the musculoskeletal, endocrine, immune, and nervous systems. Nutritional consultancy based on the 4R’s is important for the wise stewardship of the hydration, feeding, and supplementation strategies to achieve a timely recovery.

Neuroendocrine Response to Psychosocial Stressors, Inflammation Mediators and Brain-periphery Pathways of Adaptation

Threats, challenging events, adverse experiences, predictable or unpredictable, namely stressors, characterize life, being unavoidable for humans. The hypothalamus-pituitary-adrenal axis (HPA) and the sympathetic nervous system (SNS) are well-known to underlie adaptation to psychosocial stress in the context of other interacting systems, signals and mediators. However, much more effort is necessary to elucidate these modulatory cues for a better understanding of how and why the "brain-body axis" acts for resilience or, on the contrary, cannot cope with stress from a biochemical and biological point of view. Indeed, failure to adapt increases the risk of developing and/or relapsing mental illnesses such as burnout, post-traumatic stress disorder (PTSD), and at least some types of depression, even favoring/worsening neurodegenerative and somatic comorbidities, especially in the elderly. We will review here the current knowledge on this area, focusing on works presenting the main brain centers responsible for stressor interpretation and processing, together with those underscoring the physiology/biochemistry of endogenous stress responses. Autonomic and HPA patterns, inflammatory cascades and energy/redox metabolic arrays will be presented as allostasis promoters, leading towards adaptation to psychosocial stress and homeostasis, but also as possible vulnerability factors for allostatic overload and non-adaptive reactions. Besides, the existence of allostasis buffering systems will be treated. Finally, we will suggest promising lines of future research, particularly the use of animal and cell culture models together with human studies by means of high-throughput multi-omics technologies, which could entangle the biochemical signature of resilience or stress-related illness, a considerably helpful facet for improving patients' treatment and monitoring.

Race and ethnic variation in college students' allostatic regulation of racism-related stress

Racism-related stress is thought to contribute to widespread race/ethnic health inequities via negative emotion and allostatic stress process up-regulation. Although prior studies document race-related stress and health correlations, due to methodological and technical limitations, they have been unable to directly test the stress-reactivity hypothesis in situ. Guided by theories of constructed emotion and allostasis, we developed a protocol using wearable sensors and daily surveys that allowed us to operationalize and time-couple self-reported racism-related experiences, negative emotions, and an independent biosignal of emotional arousal. We used data from 100 diverse young adults at a predominantly White college campus to assess racism-related stress reactivity using electrodermal activity (EDA), a biosignal of sympathetic nervous system activity. We find that racism-related experiences predict both increased negative emotion risk and heightened EDA, consistent with the proposed allostatic model of health and disease. Specific patterns varied across race/ethnic groups. For example, discrimination and rumination were associated with negative emotion for African American students, but only interpersonal discrimination predicted increased arousal via EDA. The pattern of results was more general for Latinx students, for whom interpersonal discrimination, vicarious racism exposure, and rumination significantly modulated arousal. As with Latinx students, African students were particularly responsive to vicarious racism while 1.5 generation Black students were generally not responsive to racism-related experiences. Overall, these findings provide support for allostasis-based theories of mental and physical health via a naturalistic assessment of the emotional and sympathetic nervous system responding to real-life social experiences.

Human attachments shape interbrain synchrony toward efficient performance of social goals

The human brain has undergone massive expansion across primate evolution through life amidst multi-layered social attachments; within families, among friends, and between clan members and this enabled humans to coordinate their brains with those of others toward the execution of complex social goals.  We examined how human attachments facilitate efficient, resource-sensitive performance of social goals by balancing neural and behavioral synchrony. Using hyperscanning EEG, we collected neural data from male-female pairs in three groups (N=158, 79 pairs); long-term couples, best friends, and unfamiliar group members, during two ecologically-valid naturalistic tasks; motor coordination and empathy giving.  Across groups and tasks, neural synchrony was supported by behavior coordination and orchestrated multiple neural rhythms.  In the goal-directed motor task, interbrain synchrony implicated beta and gamma rhythms localized to sensorimotor areas. Couples showed the highest neural synchrony combined with greatest behavioral synchrony and such brain-behavior linkage resulted in speedy performance, conserving energy in the long run.  The socially-oriented empathy task triggered neural synchrony in widely-distributed sensorimotor and bilateral temporal regions, integrated alpha, beta, and gamma rhythms, and implicated brain-behavior complementarity; couples displayed the highest behavioral synchrony combined with lowest neural synchrony toward greatest felt support while strangers exhibited the opposite pattern.  Findings suggest that human attachments provide a familiar backdrop of temporal regularities, required for the brain's allostatic function, and interbrain and behavioral synchrony are sculpted by familiarity and closeness toward resource-sensitive performance of survival-related social goals, toiled by two.

The N400 indexes acquisition of novel emotion concepts via conceptual combination

The ability to learn new emotion concepts is adaptive and socially valuable as it communicates culturally held understandings about values, goals, and experiences. Yet, little work has examined the underlying mechanisms that allow for new emotion concepts and words to be integrated into the conceptual system. One such mechanism may be conceptual combination, or the ability to form novel concepts by dynamically combining previously acquired conceptual knowledge. In this study, we used event-related potentials (ERPs) to investigate the electrophysiological correlates of novel emotion concept acquisition via conceptual combination. Participants were briefly trained on 30 novel emotion combinations, each consisting of two English emotion words (the components; e.g., "sadness + fatigue") and a pseudoword (the target; e.g., "despip"). Participants then completed a semantic congruency task while ERPs were recorded. On each trial, two components were presented serially, followed by a target; participants judged whether the target was a valid combination of the preceding components. Targets could be correct or incorrect trained pseudowords, or new untrained pseudowords. Furthermore, components could be presented in reversed order (e.g., "fatigue" then "sadness") or as synonyms (e.g., "exhaustion" for "fatigue"). Consistent with our main hypotheses, we found a main effect of target, such that the correct combinations showed reduced N400 amplitudes when compared to both incorrect and untrained pseudowords. Critically, this effect held regardless of how the preceding components were presented, suggesting deeper semantic learning. These results extend prior findings on conceptual combination and novel word learning, and are congruent with predictive processing accounts of brain function.

Enhanced bodily states of fear facilitates bias perception of fearful faces

We investigated whether enhanced interoceptive bodily states of fear would facilitate recognition of the fearful faces. Participants performed an emotional judgment task after a bodily imagery task inside a functional magnetic resonance imaging scanner. In the bodily imagery task, participants were instructed to imagine feeling the bodily sensations of two specific somatotopic patterns: a fear-associated bodily sensation (FBS) or a disgust-associated bodily sensation (DBS). They were shown faces expressing various levels of fearfulness and disgust and instructed to classify the facial expression as fear or disgust. We found a stronger bias favoring the “fearful face” under the congruent FBS condition than under the incongruent DBS condition. The brain response to fearful versus intermediate faces increased in the fronto-insular-temporal network under the FBS condition, but not the DBS condition. The fearful face elicited activity in the anterior cingulate cortex and extrastriate body area under the FBS condition relative to the DBS condition. Furthermore, functional connectivity between the anterior cingulate cortex/extrastriate body area and the fronto-insular-temporal network was modulated according to the specific bodily sensation. Our findings suggest that somatotopic patterns of bodily sensation provide informative access to the collective visceral state in the fear processing via the fronto-insular-temporal network.

Corticotropin-releasing factor neurotransmission in the lateral hypothalamus modulates the tachycardiac response during acute emotional stress in rats

The lateral hypothalamus (LH) is implicated in the physiological and behavioral responses during stressful events. However, the local neurochemical mechanisms related to control of stress responses by this hypothalamic area are not completely understood. Therefore, in this study we evaluated the involvement of CRFergic neurotransmission acting through the CRF₁ receptor within the LH in cardiovascular responses evoked by an acute session of restraint stress in rats. For this, we investigated the effect of bilateral microinjection of different doses (0.01, 0.1 and 1 nmol/100 nL) of the selective CRF₁ receptor antagonist CP376395 into the LH on arterial pressure and heart rate increases and decrease in tail skin temperature evoked by acute restraint stress. We found that all doses of the CRF₁ receptor antagonist microinjected into the LH decreased the restraint-evoked tachycardia, but without affecting the arterial pressure and tail skin temperature responses. Additionally, treatment of the LH with CP376395 at the doses of 0.1 and 1 nmol/100 nL increased the basal values of both heart rate and arterial pressure, whereas the dose of 0.1 nmol/100 nL decreased the skin temperature. Taken together, these findings indicate that CRFergic neurotransmission in the LH, acting through activation of local CRF₁ receptors, plays a facilitatory role in the tachycardia observed during aversive threats, but without affecting the pressor and tail skin temperature responses. Our results also provide evidence that LH CRFergic neurotransmission in involved in tonic maintenance of cardiovascular function.

Reinterpreting patterns of variation in human thyroid function: An evolutionary ecology perspective

Two hundred million people worldwide experience some form of thyroid disorder, with women being especially at risk. However, why human thyroid function varies between populations, individuals, and across the lifespan has attracted little research to date. This limits our ability to evaluate the conditions under which patterns of variation in thyroid function are best understood as 'normal' or 'pathological'. In this review, we aim to spark interest in research aimed at understanding the causes of variation in thyroid phenotypes. We start by assessing the biomedical literature on thyroid imbalance to discuss the validity of existing reference intervals for diagnosis and treatment across individuals and populations. We then propose an evolutionary ecological framework for understanding the phylogenetic, genetic, ecological, developmental, and physiological causes of normal variation in thyroid function. We build on this approach to suggest testable predictions for how environmental challenges interact with individual circumstances to influence the onset of thyroid disorders. We propose that dietary changes, ecological disruptions of co-evolutionary processes during pregnancy and with pathogens, emerging infections, and exacerbated stress responses can contribute to explaining the onset of thyroid diseases. For patients to receive the best personalized care, research into the causes of thyroid variation at multiple levels is needed.

High-resolution, relational, resonance-based, electroencephalic mirroring (HIRREM) improves symptoms and autonomic function for insomnia: A randomized, placebo-controlled clinical trial

INTRODUCTION

Effective insomnia interventions that also address autonomic dysregulation are lacking. We evaluate high-resolution, relational, resonance-based, electroencephalic mirroring (HIRREM® ), in a randomized, controlled clinical trial. HIRREM is a noninvasive, closed-loop, allostatic, acoustic stimulation neurotechnology, to support self-optimization of brain rhythms.

METHODS

One hundred and seven adults (mean age 45.7, SD ± 5.6, 73 women), with Insomnia Severity Index (ISI) scores of ≥15, received ten, 90-min sessions of HIRREM, with tones linked to brainwaves (LB, 56), or random tones not linked to brainwaves (NL, 51), as an active, sham placebo. Outcomes were obtained at enrollment (V1), 1-7 days (V2), 8-10 weeks (V3), and 16-18 weeks (V4) after intervention. Primary outcome was differential change in ISI from V1 to V3. Secondary measures assessed depression (BDI), anxiety (BAI), quality of life (EQ-5D), and a sleep diary. Ten minute recordings of HR and BP allowed analysis of heart rate variability (HRV) and baroreflex sensitivity (BRS).

RESULTS

Of 107 randomized, 101 completed the intervention. Intention-to-treat analysis (107) of change from V1 to V3 revealed a mean reduction of ISI in NL of -4.93 (SE ± 0.76) points, with additional, significant reduction of -2.05 points (0.74) in LB (total reduction of -6.98, p = .045). Additional reduction of -2.30 points (0.76) was still present in the LB at V4 (p = .058). Total ISI reduction from V1 to V4 was -5.90 points for NL and -7.93 points in LB. There were group differences (p < .05) for multiple HRV and BRS measures (rMSSD, SDNN, HF alpha, and Seq ALL), as well as total sleep time, sleep onset latency, and sleep efficiency. There were no serious adverse events.

CONCLUSIONS

Results of this controlled clinical trial showed clinically relevant reduction of insomnia symptoms with HIRREM, over, and above an active, sham control, with associated, durable improvement in autonomic cardiovascular regulation.

Future climates: Markov blankets and active inference in the biosphere

We formalize the Gaia hypothesis about the Earth climate system using advances in theoretical biology based on the minimization of variational free energy. This amounts to the claim that non-equilibrium steady-state dynamics-that underwrite our climate-depend on the Earth system possessing a Markov blanket. Our formalization rests on how the metabolic rates of the biosphere (understood as Markov blanket's internal states) change with respect to solar radiation at the Earth's surface (i.e. external states), through the changes in greenhouse and albedo effects (i.e. active states) and ocean-driven global temperature changes (i.e. sensory states). Describing the interaction between the metabolic rates and solar radiation as climatic states-in a Markov blanket-amounts to describing the dynamics of the internal states as actively inferring external states. This underwrites climatic non-equilibrium steady-state through free energy minimization and thus a form of planetary autopoiesis.

Losing Ourselves: Active Inference, Depersonalization, and Meditation

Disruptions in the ordinary sense of selfhood underpin both pathological and "enlightened" states of consciousness. People suffering from depersonalization can experience the loss of a sense of self as devastating, often accompanied by intense feelings of alienation, fear, and hopelessness. However, for meditative contemplatives from various traditions, "selfless" experiences are highly sought after, being associated with enduring peace and joy. Little is understood about how these contrasting dysphoric and euphoric experiences should be conceptualized. In this paper, we propose a unified account of these selfless experiences within the active inference framework. Building on our recent active inference research, we propose an account of the experiences of selfhood as emerging from a temporally deep generative model. We go on to develop a view of the self as playing a central role in structuring ordinary experience by "tuning" agents to the counterfactually rich possibilities for action. Finally, we explore how depersonalization may result from an inferred loss of allostatic control and contrast this phenomenology with selfless experiences reported by meditation practitioners. We will show how, by beginning with a conception of self-modeling within an active inference framework, we have available to us a new way of conceptualizing the striking experiential similarities and important differences between these selfless experiences within a unifying theoretical framework. We will explore the implications for understanding and treating dissociative disorders, as well as elucidate both the therapeutic potential, and possible dangers, of meditation.

Discrimination and systemic inflammation: A critical review and synthesis

Exposure to discrimination or unfair treatment has emerged as an important risk factor for illness and disease that disproportionately affects racial and ethnic minorities. Discriminatory experiences may operate like other stressors in that they activate physiological responses that adversely affect the maintenance of homeostasis. Research suggests that inflammation plays a critical role in the pathophysiology of stress-related diseases. Recent findings on discrimination and inflammation are discussed. We highlight limitations in the current evidence and provide recommendations for future studies that seek to examine the association between discrimination and inflammation.

Global gene expression profile under low-temperature conditions in the brain of the grass carp (Ctenopharyngodon idellus)

Grass carp is an important commercial fish widely cultivated in China. A wide range of temperatures, particularly extremely low temperatures, have dramatic effects on the aquaculture of this teleost. However, relatively few studies have characterized the molecular responses of grass carp exposed to acute cooling in natural environment. Here, we investigated the transcriptome profiles of the grass carp brain in response to cooling. Through regulation pattern analyses, we identified 2,513 differentially expressed genes (DEGs) that responded to moderate cold stress (12°C), while 99 DEGs were induced by severe low temperature (4°C).The pathway analyses revealed that the DEGs sensitive to moderate cold were largely enriched in steroid biosynthesis, spliceosome, translation, protein metabolism, phagosome, gap junction and estrogen signaling pathways. Additionally, we discerned genes most likely involved in low temperature tolerance, of which the MAPK signaling pathway was dominantly enriched. Further examination and characterization of the candidate genes may help to elucidate the mechanisms underpinning extreme plasticity to severe cold stress in grass carp.

Anticipated consequences as the primary causes of suicidal behavior: Evidence from a laboratory study

Due to the limitations of conducting experimental studies on suicide, little is known about its causes. Based on basic behavioral research, we hypothesized that the anticipated consequences of suicidal behavior (e.g., stress relief) are the primary causes of suicidal behavior, and experienced antecedents (e.g., stress) are secondary causes. We evaluated this general hypothesis by testing the causal effects of these two broad phenomena on virtual reality (VR) suicide in 497 participants across five groups. On their own, experienced antecedent manipulations (i.e., stress and rejection) did not significantly increase VR suicide rates relative to the control group. On its own, the anticipated consequence manipulation (i.e., instruction that engaging in VR suicide would allow one to avoid a future stressor) caused a large increase in the VR suicide rate. In the context of an experienced antecedent manipulation (i.e., stress), this anticipated consequence manipulation caused an even larger increase in the VR suicide rate. These findings suggest that the anticipated consequences of suicidal behavior (e.g., avoidance or escape from something unpleasant, attaining something pleasant) are the primary causes of suicidal behavior, and that experienced antecedents (e.g., stress) serve as secondary causes when they make an anticipated consequence of suicidal behavior seem more appealing.

The Circularity of the Embodied Mind

From an embodied and enactive point of view, the mind-body problem has been reformulated as the relation between the lived or subject body on the one hand and the physiological or object body on the other ("body-body problem"). The aim of the paper is to explore the concept of circularity as a means of explaining the relation between the phenomenology of lived experience and the dynamics of organism-environment interactions. This concept of circularity also seems suitable for connecting enactive accounts with ecological psychology. It will be developed in a threefold way: (1) As the circular structure of embodiment, which manifests itself (a) in the homeostatic cycles between the brain and body and (b) in the sensorimotor cycles between the brain, body, and environment. This includes the interdependence of an organism's dispositions of sense-making and the affordances of the environment. (2) As the circular causality, which characterizes the relation between parts and whole within the living organism as well as within the organism-environment system. (3) As the circularity of process and structure in development and learning. Here, it will be argued that subjective experience constitutes a process of sense-making that implies (neuro-)physiological processes so as to form modified neuronal structures, which in turn enable altered future interactions. On this basis, embodied experience may ultimately be conceived as the integration of brain-body and body-environment interactions, which has a top-down, formative, or ordering effect on physiological processes. This will serve as an approach to a solution of the body-body problem.

Spontaneous recovery, time course, and circadian influence on habituation of the cardiovascular responses to repeated restraint stress in rats

We investigated the spontaneous recovery, time course, and the influence of the time of day on the habituation of the cardiovascular responses with repeated exposure to restraint stress in male rats. Habituation of the corticosterone response to repeated restraint stress was also evaluated. The circulating corticosterone response decreased during both the stress and recovery periods of the tenth session of restraint. Habituation of the cardiovascular responses was identified as a faster return to baseline values of the heart rate (HR) and blood pressure (BP) during the recovery period of the tenth session of restraint. Habituation of the HR and BP was still observed after 10 days of discontinuation of the repeated exposure to restraint stress. However, spontaneous recovery of habituated responses was observed 20 days after the final restraint stress session. Time course analysis revealed decreased HR response during the recovery period of the third restraint session, without further reduction on the fifth, seventh, and tenth sessions. Decreased BP response was identified on the third and fifth sessions, whereas reduced tail skin temperature response was observed only on the fifth and seventh sessions. Regarding the time of day, habituation of the tachycardiac response was identified at the tenth session when repeated restraint stress was performed in the morning and night periods, but not in the afternoon. These findings provided evidence of spontaneous recovery of the habituation of cardiovascular responses to repeated restraint stress. Moreover, cardiovascular habituation was dependent on the number of trials and time of day.

Theoretical, and epistemological challenges in scientific investigations of complex emotional states in animals

This review brings to light critical epistemological and theoretical considerations when studying complex emotional states in animals. We discuss anthropomorphic and Umwelt perspectives of nonhuman animals and the ways in which distinct theories of consciousness and neural processing may restrict the potential for the development of knowledge on the topic. Within the same line of argumentation, we consider influences of the debate between monism and dualism and psychology's behaviorism and cognitive theories. Finally, we contrast the affective consciousness, higher-order emotional consciousness, and constructed emotion theories to further our understanding of complex emotional states in animals.

Effects of Depressive Symptoms, Feelings, and Interoception on Reward-Based Decision-Making: Investigation Using Reinforcement Learning Model

Background: In this study, we examined the relationships between reward-based decision-making in terms of learning rate, memory rate, exploration rate, and depression-related subjective emotional experience, in terms of interoception and feelings, to understand how reward-based decision-making is impaired in depression. Methods: In all, 52 university students were randomly assigned to an experimental group and a control group. To manipulate interoception, the participants in the experimental group were instructed to tune their internal somatic sense to the skin-conductance-response waveform presented on a display. The participants in the control group were only instructed to stay relaxed. Before and after the manipulation, the participants completed a probabilistic reversal-learning task to assess reward-based decision-making using reinforcement learning modeling. Similarly, participants completed a probe-detection task, a heartbeat-detection task, and self-rated scales. Results: The experimental manipulation of interoception was not successful. In the baseline testing, reinforcement learning modeling indicated a marginally-significant correlation between the exploration rate and depressive symptoms. However, the exploration rate was significantly associated with lower interoceptive attention and higher depressive feeling. Conclusions: The findings suggest that situational characteristics may be closely involved in reward exploration and highlight the clinically-meaningful possibility that intervention for affective processes may impact reward-based decision-making in those with depression.

Individual differences in biological regulation: Predicting vulnerability to drug addiction, obesity, and other dysregulatory disorders

Physiological regulation is so fundamental to survival that natural selection has greatly favored the evolution of robust regulatory systems that use both reactive and preemptive responses to mitigate the disruptive impact of biological and environmental challenges on physiological function. In good health, robust regulatory systems provide little insight into the typically hidden complex array of sensor-effector interactions that accomplish successful regulation. Numerous health disorders have been traced to defective regulatory mechanisms, and generations of scientists have worked to discover ways to correct these defects and restore normal physiological function. Despite progress, numerous chronic health disorders remain resistant to treatment, and indeed for some disorders the incidence is increasing. We propose that an individual's susceptibility to acquire certain persistent dysregulatory disorders can be traced to interindividual variation in how that individual's regulatory system responds to challenges. Preexisting reliable individual differences among regulatory systems are typically unrecognized until appropriate regulatory challenges (e.g., exposure to a drug of abuse) lead to dysregulation (e.g., drug addiction). Specific characteristics of an individual's regulatory responsiveness may include etiological factors that participate in the acquisition, escalation and maintenance of health disorders characterized by dysregulation. By appropriately challenging a healthy individual's regulatory systems to identify its underlying characteristics, it is possible to ascertain whether an individual has an elevated risk for acquiring a dysregulated health condition and thereby enable strategies designed to prevent, rather than treat, the condition. This model is applied to drug addiction, and in addition we relate this approach to other dysregulated conditions such as obesity. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

Context-aware experience sampling reveals the scale of variation in affective experience

Emotion research typically searches for consistency and specificity in physiological activity across instances of an emotion category, such as anger or fear, yet studies to date have observed more variation than expected. In the present study, we adopt an alternative approach, searching inductively for structure within variation, both within and across participants. Following a novel, physiologically-triggered experience sampling procedure, participants' self-reports and peripheral physiological activity were recorded when substantial changes in cardiac activity occurred in the absence of movement. Unsupervised clustering analyses revealed variability in the number and nature of patterns of physiological activity that recurred within individuals, as well as in the affect ratings and emotion labels associated with each pattern. There were also broad patterns that recurred across individuals. These findings support a constructionist account of emotion which, drawing on Darwin, proposes that emotion categories are populations of variable instances tied to situation-specific needs.

Leptin level as a biomarker of uncontrolled eating in obesity and overweight

BACKGROUND

Uncontrolled eating (UE) showed important relationships with the development of obesity. Homeostatic regulations of feeding and energy balance, as well as hedonic eating, are regulated by leptin.

AIMS

The aims of this study were (1) to assess eating behaviors of Algerian adults as measured by the 51-item eating inventory; we also evaluate changes in the Three-Factor Eating Questionnaire (TFEQ) scores according to the body mass index (BMI) category; (2) to examine the association between the scores of the three TFEQ factors and the BMI values of the participants; and (3) to examine whether leptin concentrations are associated with eating behavior. Our hypothesis is that participants with obesity and high concentrations of leptin might display uncontrolled eating behavior.

METHODS

The subjects were 190 participants (60 obese, 60 overweight, and 70 lean subjects). The eating behavior was measured by using the 51-item eating inventory. Serum insulin concentrations were assessed by radioimmunoassay and were used to calculate homeostasis model assessment (HOMA). Serum leptin was quantified by the enzyme-linked immunosorbent assay (ELISA).

RESULTS

Obese and overweight subjects showed hyperphagic behavior, i.e., uncontrolled eating. The logistic regression analysis showed an effect of leptin, HOMA, uncontrolled eating, and emotional eating on BMI. Leptin levels were associated with the uncontrolled eating and influenced by insulin sensitivity.

CONCLUSIONS

The uncontrolled eating reflects hyperphagic eating behavior in obese and overweight subjects. Coexistence of uncontrolled eating and high level of leptin demonstrates a state of leptin resistance resulting in an inability to detect satiety. High circulating leptin can be considered a potential biomarker of uncontrolled eating.

Trauma or Drama: A Predictive Processing Perspective on the Continuum of Stress

The notion of psychological trauma has been liberally used both in clinical literature and general discourse. However, no consensus exists on its exact meaning and definition. Whereas traditionally trauma has been mostly associated with criterion A of acute and posttraumatic stress disorders (PTSDs) as defined in the Diagnostic and Statistical Manual of Mental Disorders, many researchers find this definition too constraining and not accounting for the complexity and many aspects of trauma. This touched off a quest for a broader more accommodating trauma concept, and a dimensional view of trauma with PTSD as its extreme manifestation has been suggested. The dimensional view also has its detractors arguing that "conceptual bracket creep" may undermine the category's utility. Both categorical and dimensional views mostly rely on trauma's clinical phenomenology and lack a unified theoretical basis. In an attempt to reconcile this contradiction, a hybrid categorical-dimensional model of trauma based on the general theory of stress has been recently proposed (Krupnik, 2019). Herein, I explore the categorical boundary of the trauma concept, as posited by the model, within the predictive processing framework (PPF). I integrate the PPF view with the theory of stress. In conclusion, I briefly discuss how the proposed model of trauma may guide clinical practice.

Aggressive behavior during toddlerhood: Interrelated effects of prenatal risk factors, negative affect, and cognition

Prenatal risk, temperamental negative affect, and specific cognitive abilities have all individually been identified as predictors of behavior problems during early childhood, but less is known about their interplay in relation to aggression during toddlerhood. This study examined the main and interaction effects of prenatal risk, negative affect, inhibitory control, attention, and vocabulary in the prediction of aggression in 150 children (75 boys). During pregnancy, a cumulative risk index was calculated based on the presence of 10 well-established maternal risk factors, such as prenatal substance use, maternal psychiatric disorder, and financial problems. Negative affect was measured at 6 and 20 months using maternal report. Child cognition was examined at 30 months using laboratory tasks for inhibitory control and attention, and a questionnaire was administered to assess vocabulary. In addition, mothers reported on their children's aggressive behavior at 30 months. Higher prenatal risk and negative affect at 20 months and, to a lesser extent, at 6 months were related to more aggression at 30 months. Poorer inhibitory control and, to a lesser extent, vocabulary at 30 months also predicted higher levels of aggressive behavior. Two-way interaction effects were found for cumulative risk and inhibitory control, negative affect (at 20 months) and inhibitory control, and negative affect (at 6 months) and vocabulary: aggressive behavior was most pronounced when combinations of high prenatal risk, high negative affect, and poor cognition were present. These results suggest that the impact of prenatal risk and child temperament depends in part on child's cognitive development during toddlerhood.

Multiple areas of the cerebral cortex influence the stomach

Despite the longstanding appreciation that how we move, think, and feel has an impact on stomach function, the areas of the cerebral cortex that are the origin of these influences are largely unknown. Here we identify the cortical areas that influence the rat stomach. Output neurons in the rostral insula are the major cortical source of influence over parasympathetic control of the stomach, whereas output neurons in sensorimotor areas of the cortex are the major source of influence over sympathetic control. Thus, cortical areas involved in action, interoception, and emotion differentially influence stomach function.

The central nervous system both influences and is influenced by the gastrointestinal system. Most research on this gut–brain connection has focused on how ascending signals from the gut and its microbiome alter brain function. Less attention has focused on how descending signals from the central nervous system alter gut function. Here, we used retrograde transneuronal transport of rabies virus to identify the cortical areas that most directly influence parasympathetic and sympathetic control of the rat stomach. Cortical neurons that influence parasympathetic output to the stomach originated from the rostral insula and portions of medial prefrontal cortex, regions that are associated with interoception and emotional control. In contrast, cortical neurons that influence sympathetic output to the stomach originated overwhelmingly from the primary motor cortex, primary somatosensory cortex, and secondary motor cortex, regions that are linked to skeletomotor control and action. Clearly, the two limbs of autonomic control over the stomach are influenced by distinct cortical networks.

Habituation of the cardiovascular response to restraint stress is inhibited by exposure to other stressor stimuli and exercise training

This study evaluated the effect of exposure to either a chronic variable stress (CVS) protocol or social isolation, as well as treadmill exercise training, in the habituation of the cardiovascular response upon repeated exposure to restraint stress in rats. The habituation of the corticosterone response to repeated restraint stress was also evaluated. For this, animals were subjected to either acute or 10 daily sessions of 60 min of restraint stress. CVS and social isolation protocols lasted for 10 consecutive days, whereas treadmill training was performed for 1 h per day, 5 days per week for 8 weeks. We observed that the increase in serum corticosterone was reduced during both the stress and the recovery period of the 10th session of restraint. Habituation of the cardiovascular response was identified in terms of a faster return of heart rate to baseline values during the recovery period of the 10th session of restraint. The increase in blood pressure and the decrease in tail skin temperature were similar at the 1st and 10th session of restraint. Exposure to CVS, social isolation or treadmill exercise training inhibited the habituation of the restraint-evoked tachycardia. Additionally, CVS increased the blood pressure response at the 10th session of restraint, whereas social isolation enhanced both the tachycardia during the first session and the drop in skin temperature at the 10th session of restraint. Taken together, these findings provide new evidence that pathologies evoked by stress might be related to impairment in the habituation process to homotypic stressors.

Quantitative meta-analysis of heart rate variability finds reduced parasympathetic cardiac tone in women compared to men during laboratory-based social stress

Heart rate variability (HRV) is the inter-beat interval variation between consecutive heartbeats and an autonomic reflection of emotional regulatory abilities to flexibly respond to challenges, such as psychosocial stress. Whereas there are known sex differences in stress-induced hormonal and emotional responses, we identified a gap in our understanding of sex-specific autonomic cardiac control during stress. Thus, we assessed HRV prior to, during and after administration of a public speech task in healthy participants (n = 929) according to sex. Our meta-analysis found that during stress, women had lower HRV than men, with an overall Hedges' g of 0.29 (p < 0.0001) and 0.29 (p = 0.0003) for fixed and random effects models, respectively. We did not find significant heterogeneity or evidence of publication bias. Analyses of additional timepoints showed no baseline difference and marginally lower HRV in women during anticipation and recovery. Findings of the present meta-analysis confirm sex differences in stress-induced hyperarousal and form a justification for implementation of mechanistic studies evaluating gonadal hormones, their potent metabolites and pro-inflammatory cytokines as mediators of this relationship.

Late weaning and maternal closeness, associated with advanced motor and visual maturation, reinforce autonomy in healthy, 2-year-old children

We studied neurodevelopmental outcomes and behaviours in healthy 2-year old children (N = 1306) from Brazil, India, Italy, Kenya and the UK participating in the INTERGROWTH-21^st Project. There was a positive independent relationship of duration of exclusive breastfeeding (EBF) and age at weaning with gross motor development, vision and autonomic physical activities, most evident if children were exclusively breastfed for ≥7 months or weaned at ≥7 months. There was no association with cognition, language or behaviour. Children exclusively breastfed from birth to <5 months or weaned at >6 months had, in a dose-effect pattern, adjusting for confounding factors, higher scores for "emotional reactivity". The positive effect of EBF and age at weaning on gross motor, running and climbing scores was strongest among children with the highest scores in maternal closeness proxy indicators. EBF, late weaning and maternal closeness, associated with advanced motor and vision maturation, independently influence autonomous behaviours in healthy children.

Beginning with biology: “Aspects of cognition” exist in the service of the brain's overall function as a resource-regulator

Lieder and Griffiths rightly urge that computational cognitive models be constrained by resource usage, but they should go further. The brain's primary function is to regulate resource usage. As a consequence, resource usage should not simply select among algorithmic models of “aspects of cognition.” Rather, “aspects of cognition” should be understood as existing in the service of resource management.

Keep calm and carry on: electrophysiological evaluation of emotional anticipation in the second language

Investigations of the so-called ‘foreign language effect’ have shown that emotional experience is language-dependent in bilingual individuals. Response to negative experiences, in particular, appears attenuated in the second language (L2). However, the human brain is not only reactive, but it also builds on past experiences to anticipate future events. Here, we investigated affective anticipation in immersed Polish–English bilinguals using a priming paradigm in which a verbal cue of controlled affective valence allowed making predictions about a subsequent picture target. As expected, native word cues with a negative valence increased the amplitude of the stimulus preceding negativity, an electrophysiological marker of affective anticipation, as compared with neutral ones. This effect was observed in Polish–English bilinguals and English monolinguals alike. The contrast was non-significant when Polish participants were tested in English, suggesting a possible reduction in affective sensitivity in L2. However, this reduction was not validated by a critical language × valence interaction in the bilingual group, possibly because they were highly fluent in English and because the affective stimuli used in the present study were particularly mild. These results, which are neither fully consistent nor inconsistent with the foreign language effect, provide initial insights into the electrophysiology of affective anticipation in bilingualism.

Emotional distress, brain functioning, and biobehavioral processes in cancer patients: a neuroimaging review and future directions

Despite emerging evidence that distress and adversity can contribute to negative health outcomes in cancer, little is known about the brain networks, regions, or circuits that can contribute to individual differences in affect/distress states and health outcomes in treated cancer patients. To understand the state-of-the-science in this regard, we reviewed neuroimaging studies with cancer patients that examined the associations between negative affect (distress) and changes in the metabolism or structure of brain regions. Cancer patients showed changes in function and/or structure of key brain regions such as the prefrontal cortex, thalamus, amygdala, hippocampus, cingulate cortex (mainly subgenual area), hypothalamus, basal ganglia (striatum and caudate), and insula, which are associated with greater anxiety, depression, posttraumatic stress disorder (PTSD) symptoms, and distress. These results provide insights for understanding the effects of these psychological and emotional factors on peripheral stress-related biobehavioral pathways known to contribute to cancer progression and long-term health outcomes. This line of work provides leads for understanding the brain-mediated mechanisms that may explain the health effects of psychosocial interventions in cancer patients and survivors. A multilevel and integrated model for distress management intervention effects on psychological adaptation, biobehavioral processes, cancer pathogenesis, and clinical outcomes is proposed for future research.

The sense of should: A biologically-based framework for modeling social pressure

What is social pressure, and how could it be adaptive to conform to others' expectations? Existing accounts highlight the importance of reputation and social sanctions. Yet, conformist behavior is multiply determined: sometimes, a person desires social regard, but at other times she feels obligated to behave a certain way, regardless of any reputational benefit-i.e. she feels a sense of should. We develop a formal model of this sense of should, beginning from a minimal set of biological premises: that the brain is predictive, that prediction error has a metabolic cost, and that metabolic costs are prospectively avoided. It follows that unpredictable environments impose metabolic costs, and in social environments these costs can be reduced by conforming to others' expectations. We elaborate on a sense of should's benefits and subjective experience, its likely developmental trajectory, and its relation to embodied mental inference. From this individualistic metabolic strategy, the emergent dynamics unify social phenomenon ranging from status quo biases, to communication and motivated cognition. We offer new solutions to long-studied problems (e.g. altruistic behavior), and show how compliance with arbitrary social practices is compelled without explicit sanctions. Social pressure may provide a foundation in individuals on which societies can be built.

Association between Mean Heart Rate and Recurrence Quantification Analysis of Heart Rate Variability in End-Stage Renal Disease

Linear heart rate variability (HRV) indices are dependent on the mean heart rate, which has been demonstrated in different models (from sinoatrial cells to humans). The association between nonlinear HRV indices, including those provided by recurrence plot quantitative analysis (RQA), and the mean heart rate (or the mean cardiac period, also called meanNN) has been scarcely studied. For this purpose, we analyzed RQA indices of five minute-long HRV time series obtained in the supine position and during active standing from 30 healthy subjects and 29 end-stage renal disease (ESRD) patients (before and after hemodialysis). In the supine position, ESRD patients showed shorter meanNN (i.e., faster heart rate) and decreased variability compared to healthy subjects. The healthy subjects responded to active standing by shortening the meanNN and decreasing HRV indices to reach similar values of ESRD patients. Bivariate correlations between all RQA indices and meanNN were significant in healthy subjects and ESRD after hemodialysis and for most RQA indices in ESRD patients before hemodialysis. Multiple linear regression analyses showed that RQA indices were also dependent on the position and the ESRD condition. Then, future studies should consider the association among RQA indices, meanNN, and these other factors for a correct interpretation of HRV.

In search of optimal resilience ratios: Differential influences of neurobehavioral factors contributing to stress-resilience spectra

The ability to adapt to stressful circumstances, known as emotional resilience, is a key factor in the maintenance of mental health. Several individual biomarkers of the stress response (e.g., corticosterone) that influence an animal's position along the continuum that ranges from adaptive allostasis to maladaptive allostatic load have been identified. Extending beyond specific biomarkers of stress responses, however, it is also important to consider stress-related responses relative to other relevant responses for a thorough understanding of the underpinnings of adaptive allostasis. In this review, behavioral, neurobiological, developmental and genomic variables are considered in the context of emotional resilience [e.g., explore/exploit behavioral tendencies; DHEA/CORT ratios and relative proportions of protein-coding/nonprotein-coding (transposable) genomic elements]. As complex and multifaceted relationships between pertinent allostasis biomediators are identified, translational applications for optimal resilience are more likely to emerge as effective therapeutic strategies.