The new field of Brain-Body Medicine: what have we learned and where are we headed?

Sophisticated regulation of micturition: review of basic neurourology

The neurological regulation of the lower urinary tract can be viewed separately from the perspective of sensory neurons and motor neurons. First, in the receptors of the bladder and urethra of sensory nerves, sensations are transmitted through the periaqueductal gray matter of the midbrain to the cerebral cortex, and the cerebrum goes through the process of decision-making. Motor neurons are divided into upper motor neurons (UMNs) and lower motor neurons (LMNs). UMNs coordinate storage and micturition in the brain stem so that synergic voiding can occur. LMNs facilitate muscle contractions in the spinal cord. The muscles involved in urinary storage and micturition are innervated by the somatic branches of sympathetic, parasympathetic, and peripheral nerves. Sympathetic nerves are responsible for contractions of urethral smooth muscles, while parasympathetic nerves originate from S2–S4 and are in charge of contractions of the bladder muscle. Somatic nerves originate from the motor neurons in Onuf’s nucleus, which is a specific part of somatic nerves. In this review, we will investigate the structures of the nervous systems related to the lower urinary tract and the regulatory system of innervation for the urinary storage and micturition and discuss the clinical significance and future prospects of neurourological research.

Cue-elicited functional connectivity of the periaqueductal gray and tonic cocaine craving

BACKGROUND

Withdrawal from chronic cocaine use leads to anxiety and dysphoria that may perpetuate habitual drug use. The pain circuit is widely implicated in the processing and manifestations of negative emotions. Numerous studies have focused on characterizing reward circuit dysfunction but relatively little is known about the pain circuit response during cocaine withdrawal.

METHODS

Here we examined the activity and connectivity of the periaqueductal gray (PAG), a hub of the pain circuit, during cocaine cue exposure in 52 recently abstinent cocaine dependent participants (CD, 42 men). Imaging data were processed with published routines, and the results were evaluated at a corrected threshold.

RESULTS

CD showed higher activation of the PAG and connectivity of the PAG with the ventromedial prefrontal cortex (vmPFC) during cocaine as compared to neutral cue exposure. PAG-vmPFC connectivity was positively and negatively correlated with tonic cocaine craving, as assessed by the Cocaine Craving Questionnaire, in male and female CD, respectively, and the sex difference was confirmed by a slope test. Granger causality analyses showed that the PAG Granger caused vmPFC time series in men and the reverse was true in women, substantiating sex differences in the directional interactions of the PAG and vmPFC.

CONCLUSION

The findings provide the first evidence in humans implicating the PAG circuit in cocaine withdrawal and cocaine craving and advance our understanding of the role of the pain circuit and negative reinforcement in sustaining habitual drug use in cocaine addiction.

Administration of moclobemide facilitates fear extinction and attenuates anxiety-like behaviors by regulating synaptic-associated proteins in a rat model of post-traumatic stress disorder

Post-traumatic stress disorder (PTSD) is a long-lasting mental disorder and accompanied by worse fear extinction. Enhanced fear memory or poor fear extinction are typical features of PTSD. Dysfunction of the serotonergic neurotransmitter system is involved in numerous mental and behavioral disorders. Monoamine oxidase A (MAOA) is important in the metabolism of serotonin and play an important role in behavious. The aim of this study was to explore the change of MAOA and effect of MAOA on fear memory in PTSD. We used single prolonged stress (SPS) to create animal model of PTSD. A startle/fear box and elevated plus maze were used to observe fear memory and anxiety level, respectively. We examined the expression of MAOA and synaptic marker protein, as well as the immunological activity of MAOA in the infralimbic cortex (IL) area, which is a critical brain region involved in emotions, especially fear regulation. We found increased anxiety-like behavior, dysfunction in fear extinction, and increased MAOA in SPS rats. After treatment with moclobemide (a selective inhibitor of MAOA), SPS rats showed significantly improved fear memory and decreased anxiety-like behavior, which indicated that moclobemide could reverse fear extinction deficit and attenuate abnormally increased levels of anxiety caused by SPS in short term. On the contrary, decreased PSD-95 and SYN1 expression in the IL region were also reversed by moclobemide. These results suggest that increased MAOA play a negative role in fear extinction and levels of anxiety in PTSD, which may be involved in change in PSD-95 and SYN1.

A New Integrative Theory of Brain-Body-Ecosystem Medicine: From the Hippocratic Holistic View of Medicine to Our Modern Society

Humans are increasingly aware that their fate will depend on the wisdom they apply in interacting with the ecosystem. Its health is defined as the condition in which the ecosystem can deliver and continuously renew its fundamental services. A healthy ecosystem allows optimal interactions between humans and the other biotic/abiotic components, and only in a healthy ecosystem can humans survive and efficiently reproduce. Thus, both the human and ecosystem health should be considered together in view of their interdependence. The present article suggests that this relationship could be considered starting from the Hippocrates (460 BC-370 BC) work "On Airs, Waters, and Places" to derive useful medical and philosophical implications for medicine which is indeed a topic that involves scientific as well as philosophical concepts that implicate a background broader than the human body. The brain-body-ecosystem medicine is proposed as a new more complete approach to safeguarding human health. Epidemiological data demonstrate that exploitation of the environment resulting in ecosystem damage affects human health and in several instances these diseases can be detected by modifications in the heart-brain interactions that can be diagnosed through the analysis of changes in heart rate variability.

Emotion regulation in patients with somatic symptom and related disorders: A systematic review

Background

Somatic symptoms and related disorders (SSD) are prevalent phenomena in the health-care system. Disturbances in emotion regulation (ER) are commonly observed in patients suffering from SSD.

Objectives

This review aimed to examine ER processes that characterize SSD by a systematic analysis of the available empirical studies.

Data sources

PsycINFO and PubMed databases for the articles published between January 1985 and June 2018.

Search terms

“emotion/al regulation” or “affect regulation” and various forms of SSD.

Study eligibility criteria

Empirical studies that a) assigned adolescent or adult patients suffering from SSD based on a clinical diagnosis, and b) examined the relationship between ER and SSD, were included.

Study synthesis methods

A tabular summary of the articles was generated according to study characteristics, study quality, variables, and findings. The findings were organized based on ER variables used in the articles and diagnoses of SSD, which were then re-organized under the main constituents of ER (attention, body, and knowledge).

Results

The findings of the 64 articles largely supported the association between SSD and disturbances in ER, which are usually shared by different diagnoses of SSD. The results indicate that patients show a reduced engagement with cognitive content of emotions. On the other hand, bodily constituents of ER seem to depict an over-reactive pattern. Similarly, the patients tend to encounter difficulties in flexibly disengaging their (spontaneous) attention from emotional material.

Limitations

There is a scarcity of longitudinal designs, randomized controlled trials, experiments, and diary studies suited to investigate the short- and long-term causal relationship between ER and SSD. Symptoms of SSD and measures to assess emotion regulation are heterogeneous.

Conclusions and implications

Assessment of ER processes is potentially useful to understand SSD and for treatment planning. Furthermore, a concurrent investigation of the dynamic interaction of the ER modalities promises insights for better understanding of the role of ER in development, course, and maintenance of SSD.

Sex differences in major depression and comorbidity of cardiometabolic disorders: impact of prenatal stress and immune exposures

Major depressive disorder topped ischemic heart disease as the number one cause of disability worldwide in 2012, and women have twice the risk of men. Further, the comorbidity of depression and cardiometabolic disorders will be one of the primary causes of disability worldwide by 2020, with women at twice the risk. Thus, understanding the sex-dependent comorbidities has public health consequences worldwide. We propose here that sex differences in MDD-cardiometabolic comorbidity originate, in part, from pathogenic processes initiated in fetal development that involve sex differences in shared pathophysiology between the brain, the vascular system, the CNS control of the heart and associated hormonal, immune, and metabolic physiology. Pathways implicate neurotrophic and angiogenic growth factors, gonadal hormone receptors, and neurotransmitters such as gamma amino butyric acid (GABA) on neuronal and vascular development of HPA axis regions, such as the paraventricular nucleus (PVN), in addition to blood pressure, in part through the renin-angiotensin system, and insulin and glucose metabolism. We show that the same prenatal exposures have consequences for sex differences across multiple organ systems that, in part, share common pathophysiology. Thus, we believe that applying a sex differences lens to understanding shared biologic substrates underlying these comorbidities will provide novel insights into the development of sex-dependent therapeutics. Further, taking a lifespan perspective beginning in fetal development provides the opportunity to target abnormalities early in the natural history of these disorders in a sex-dependent way.

Neural - hormonal responses to negative affective stimuli: Impact of dysphoric mood and sex

BACKGROUND

Maladaptive responses to negative affective stimuli are pervasive, including clinically ill and healthy people, and men and women respond differently at neural and hormonal levels. Inspired by the Research Domain Criteria initiative, we used a transdiagnostic approach to investigate the impact of sex and dysphoric mood on neural-hormonal responses to negative affective stimuli.

METHODS

Participants included 99 individuals with major depressive disorder, psychosis and healthy controls. Functional magnetic resonance imaging (fMRI) was complemented with real-time acquisition of hypothalamo-pituitary-adrenal (HPA) and -gonadal (HPG) hormones. fMRI data were analyzed in SPM8 and task-related connectivity was assessed using generalized psychophysiological interaction.

RESULTS

Across all participants, elevated cortisol response predicted lower brain activity in orbitofrontal cortex and hypothalamus-amygdala connectivity. In those with worse dysphoric mood, elevated cortisol response predicted lower activity in hypothalamus and hippocampus. In women, elevated cortisol response was associated with lower activity in medial prefrontal cortex and low hypothalamo-hippocampal connectivity. In women with high dysphoric mood, elevated cortisol response was associated with low hypothalamo-hippocampal connectivity. There were no interactions with diagnosis or medication.

LIMITATIONS

There was limited power to correct for multiple comparisons across total number of ROIs and connectivity targets; cortisol responses were relatively low.

CONCLUSIONS

We conclude that the pathophysiology in neural-hormonal responses to negative affective stimuli is shared across healthy and clinical populations and varies as a function of sex and dysphoric mood. Our findings may contribute to the development of hormonal adjunctive therapeutics that are sex-dependent, underscoring the importance of one's sex to precision medicine.

Homeostasis and the concept of 'interstitial fluids hierarchy': Relevance of cerebrospinal fluid sodium concentrations and brain temperature control (Review)

In this review, the aspects and further developments of the concept of homeostasis are discussed also in the perspective of their possible impact in the clinical practice, particularly as far as psychic homeostasis is concerned. A brief historical survey and comments on the concept of homeostasis and allostasis are presented to introduce our proposal that is based on the classical assumption of the interstitial fluid (ISF) as the internal medium for multicellular organisms. However, the new concept of a hierarchic role of ISF of the various organs is introduced. Additionally, it is suggested that particularly for some chemico‑physical parameters, oscillatory rhythms within their proper set‑ranges should be considered a fundamental component of homeostasis. Against this background, we propose that the brain ISF has the highest hierarchic role in human beings, providing the optimal environment, not simply for brain cell survival, but also for brain complex functions and the oscillatory rhythms of some parameters, such as cerebrospinal fluid sodium and brain ISF pressure waves, which may play a crucial role in brain physio‑pathological states. Thus, according to this proposal, the brain ISF represents the real internal medium since the maintenance of its dynamic intra-set-range homeostasis is the main factor for a free and independent life of higher vertebrates. Furthermore, the evolutionary links between brain and kidney and their synergistic role in H2O/Na balance and brain temperature control are discussed. Finally, it is surmised that these two interrelated parameters have deep effects on the Central Nervous System (CNS) higher integrative actions such those linked to psychic homeostasis.

The Association of Work Stress and Glycemic Status Is Partially Mediated by Autonomic Nervous System Function: Cross-Sectional Results from the Mannheim Industrial Cohort Study (MICS)

BACKGROUND

Work stress is associated with an increased risk of pre-diabetes, Type 2 diabetes, and inflammation, as well as decreased autonomic nervous system function as measured, for example, via heart rate variability. We investigated the extent to which the association between work stress and glycemic status is mediated by vagally-mediated heart rate variability (vmHRV) and/or inflammation.

METHODS

Cross-sectional data from the Mannheim Industrial Cohort Study (MICS) with 9,937 participants were analyzed. The root mean squared successive differences (RMSSD) from long-term heart rate monitoring during work and night time periods was used to index vmHRV. Fasting plasma glucose and glycosylated hemoglobin were assessed to determine glycemic status. High sensitive C-reactive protein levels were observed as a measure of systemic inflammation and the Effort-Reward-Imbalance scale was used to evaluate work stress. Mediation models were adjusted for age, sex, and occupational status, and estimations were bootstrapped (5,000 replications).

RESULTS

Effort-Reward-Imbalance was significantly negatively associated with RMSSD and both glycosylated hemoglobin and fasting plasma glucose during both work and night time periods. Effort-Reward-Imbalance was observed to have a significant direct effect on glycosylated hemoglobin and significant indirect effects, through RMSSD, on both glycemic measures during both time periods. Introducing C-reactive protein as a further mediator to the model did not alter the indirect effects observed. C-reactive protein, as an exclusive mediator, was observed to have smaller direct and indirect effects on the glycemic measures as compared to when Effort-Reward-Imbalance was included in the model.

CONCLUSIONS

Our results suggest that the association between work stress and glycemic status is partially mediated through vmHRV independent of systemic inflammation as measured by C-reactive protein. We conclude that work stress may be an additional factor that promotes development of hyperglycemic-metabolic states. If supported by prospective evidence, these results may lead to new approaches for primary prevention of hyperglycemia in the workplace.

Structural brain correlates of heart rate variability in a healthy young adult population

The high frequency component of heart rate variability (HRV) has reliably been shown to serve as an index of autonomic inhibitory control and is increasingly considered as a biomarker of adaptability and health. While several functional neuroimaging studies identified associations between regional cerebral blood flow and HRV, studies on structural brain correlates of HRV are scarce. We investigated whether interindividual differences in HRV are related to brain morphology in healthy humans. Thirty participants underwent HRV recording at rest subsequent to structural magnetic resonance imaging. Cortical reconstruction and subcortical volumetry were performed with the Freesurfer image analysis suite. The amount of resting HRV was positively correlated with the cortical thickness of an area within the right anterior midcingulate cortex (aMCC). Consistent with existing studies implicating forebrain regions in cardiac regulation, our findings show that the thickness of the right aMCC is associated with the degree of parasympathetic regulation of heart rate. Evidence for the neural correlates of interindividual differences in HRV may complement our understanding of the mechanisms underlying the association between HRV and self-regulatory capacity.

The developing brain in a multitasking world

To understand the problem of multitasking, it is necessary to examine the brain's attention networks that underlie the ability to switch attention between stimuli and tasks and to maintain a single focus among distractors. In this paper we discuss the development of brain networks related to the functions of achieving the alert state, orienting to sensory events, and developing self-control. These brain networks are common to everyone, but their efficiency varies among individuals and reflects both genes and experience. Training can alter brain networks. We consider two forms of training: (1) practice in tasks that involve particular networks, and (2) changes in brain state through such practices as meditation that may influence many networks. Playing action video games and multitasking are themselves methods of training the brain that can lead to improved performance but also to overdependence on media activity. We consider both of these outcomes and ideas about how to resist overdependence on media. Overall, our paper seeks to inform the reader about what has been learned about attention that can influence multitasking over the course of development.

Investigating the associations of self-rated health: heart rate variability is more strongly associated than inflammatory and other frequently used biomarkers in a cross sectional occupational sample

The present study aimed to investigate the possible mechanisms linking a single–item measure of global self-rated health (SRH) with morbidity by comparing the association strengths between SRH with markers of autonomic nervous system (ANS) function, inflammation, blood glucose and blood lipids. Cross–sectional comprehensive health–check data of 3947 working adults (age 42±11) was used to calculate logistic regressions, partial correlations and compare correlation strength using Olkins Z. Adjusted logistic regression models showed a negative association between SRH (higher values indicating worse health) and measures of heart rate variability (HRV). Glycemic markers were positively associated with poor SRH. No adjusted association was found with inflammatory markers, BP or lipids. In both unadjusted and adjusted linear models Pearson’s correlation strength was significantly higher between SRH with HRV measures compared to SRH with other biomarkers. This is the first study investigating the association of ANS function and SRH. We showed that a global measure of SRH is associated with HRV, and that all measures of ANS function were significantly more strongly associated with SRH than any other biomarker. The current study supports the hypothesis that the extent of brain–body communication, as indexed by HRV, is associated with self-rated health.

Neural control of the lower urinary tract

This article summarizes anatomical, neurophysiological, pharmacological, and brain imaging studies in humans and animals that have provided insights into the neural circuitry and neurotransmitter mechanisms controlling the lower urinary tract. The functions of the lower urinary tract to store and periodically eliminate urine are regulated by a complex neural control system in the brain, spinal cord, and peripheral autonomic ganglia that coordinates the activity of smooth and striated muscles of the bladder and urethral outlet. The neural control of micturition is organized as a hierarchical system in which spinal storage mechanisms are in turn regulated by circuitry in the rostral brain stem that initiates reflex voiding. Input from the forebrain triggers voluntary voiding by modulating the brain stem circuitry. Many neural circuits controlling the lower urinary tract exhibit switch-like patterns of activity that turn on and off in an all-or-none manner. The major component of the micturition switching circuit is a spinobulbospinal parasympathetic reflex pathway that has essential connections in the periaqueductal gray and pontine micturition center. A computer model of this circuit that mimics the switching functions of the bladder and urethra at the onset of micturition is described. Micturition occurs involuntarily in infants and young children until the age of 3 to 5 years, after which it is regulated voluntarily. Diseases or injuries of the nervous system in adults can cause the re-emergence of involuntary micturition, leading to urinary incontinence. Neuroplasticity underlying these developmental and pathological changes in voiding function is discussed.

Sex differences in extinction recall in posttraumatic stress disorder: a pilot fMRI study

Recent research has found that individuals with posttraumatic stress disorder (PTSD) exhibit an impaired memory of fear extinction compounded by deficient functional activation of key nodes of the fear network including the amygdala, hippocampus, ventromedial prefrontal cortex (vmPFC) and dorsal anterior cingulate cortex (dACC). Research has shown these regions are sexually dimorphic and activate differentially in healthy men and women during fear learning tasks. To explore biological markers of sex differences following exposure to psychological trauma, we used a fear learning and extinction paradigm together with functional magnetic resonance imaging (fMRI) and skin conductance response (SCR) to assess 31 individuals with PTSD (18 women; 13 men) and 25 matched trauma-exposed healthy control subjects (13 women; 12 men). Whereas no sex differences appeared within the trauma-exposed healthy control group, both psychophysiological and neural activation patterns within the PTSD group indicated deficient recall of extinction memory among men and not among women. Men with PTSD exhibited increased activation in the left rostral dACC during extinction recall compared with women with PTSD. These findings highlight the importance of tracking sex differences in fear extinction when characterizing the underlying neurobiological mechanisms of PTSD psychopathology.

Error-related functional connectivity of the thalamus in cocaine dependence

Error processing is a critical component of cognitive control, an executive function that has been widely implicated in substance misuse. In previous studies we showed that error related activations of the thalamus predicted relapse to drug use in cocaine addicted individuals (Luo et al., 2013). Here, we investigated whether the error-related functional connectivity of the thalamus is altered in cocaine dependent patients (PCD, n = 54) as compared to demographically matched healthy individuals (HC, n = 54). The results of a generalized psychophysiological interaction analysis showed negative thalamic connectivity with the ventral medial prefrontal cortex (vmPFC), in the area of perigenual and subgenual anterior cingulate cortex, in HC but not PCD (p < 0.05, corrected, two-sample t test). This difference in functional connectivity was not observed for task-residual signals, suggesting that it is specific to task-related processes during cognitive control. Further, the thalamic-vmPFC connectivity is positively correlated with the amount of cocaine use in the prior month for female but not for male PCD. These findings add to recent literature and provide additional evidence for circuit-level biomarkers of cocaine dependence.

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Error-related thalamic-vmPFC connectivity is altered in cocaine misuse.

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This altered connectivity is associated with impaired self control.

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This deficit is associated with recent cocaine use in women but not men.

Disruption of fetal hormonal programming (prenatal stress) implicates shared risk for sex differences in depression and cardiovascular disease

Comorbidity of major depressive disorder (MDD) and cardiovascular disease (CVD) represents the fourth leading cause of morbidity and mortality worldwide, and women have a two times greater risk than men. Thus understanding the pathophysiology has widespread implications for attenuation and prevention of disease burden. We suggest that sex-dependent MDD-CVD comorbidity may result from alterations in fetal programming consequent to the prenatal maternal environments that produce excess glucocorticoids, which then drive sex-dependent developmental alterations of the fetal hypothalamic-pituitary-adrenal (HPA) axis circuitry impacting mood, stress regulation, autonomic nervous system (ANS), and the vasculature in adulthood. Evidence is consistent with the hypothesis that disruptions of pathways associated with gamma aminobutyric acid (GABA) in neuronal and vascular development and growth factors have critical roles in key developmental periods and adult responses to injury in heart and brain. Understanding the potential fetal origins of these sex differences will contribute to development of novel sex-dependent therapeutics.

Tools of the trade: theory and method in mindfulness neuroscience

Mindfulness neuroscience is an emerging research field that investigates the underlying mechanisms of different mindfulness practices, different stages and different states of practice as well as different effects of practice over the lifespan. Mindfulness neuroscience research integrates theory and methods from eastern contemplative traditions, western psychology and neuroscience, and from neuroimaging techniques, physiological measures and behavioral tests. We here review several key theoretical and methodological challenges in the empirical study of mindfulness neuroscience and provide suggestions for overcoming these challenges.

The micturition switch and its forebrain influences

Dr DeGroat and Wickens has reviewed the central neural mechanisms controlling the lower urinary tract with a major focus on the brain stem circuitry that mediates the switch-like characteristics of micturition, in particular the periaqueductal grey and the pontine micturition centre (de 2012). The review culminates in a computer model of how the brainstem switch operates in animals in which forebrain influences on micturition have been removed by decerebration. In this complementary paper, we review the mechanisms of forebrain involvement in the voluntary control of human micturition and the maintenance of continence with evidence based heavily on the results of functional brain imaging experiments.

Utility of a salivary biosensor for objective assessment of surgery-related stress

PURPOSE

To evaluate the clinical utility of a salivary α-amylase (sAA) biosensor for assessing oral surgery-related stress responses and the differential effect of the personality trait of pain catastrophizing.

PATIENTS AND METHODS

A prospective cohort study was conducted in 76 healthy subjects who underwent elective removal of their third molars. Along with subjects' self-reports of anxiety and pain, biosensor-facilitated measurements of sAA levels were obtained at multiple time points during the preoperative consult, surgery, and postsurgical follow-up visits. In addition, subjects completed the Pain Catastrophizing Scale at baseline. Mixed-effect regression models examined changes in sAA levels and self-report ratings within and across visits and the contribution of pain catastrophizing.

RESULTS

The sAA levels were lower during surgery and postsurgical follow-up compared with the consult visit (P < .01). The sAA levels decreased during the surgery visit (P < .05) and did not change during the consult or follow-up visits. Individuals who reported greater helplessness to pain manifested higher sAA levels during the surgery visit (P < .05). Self-reported anxiety ratings were highest during the surgery visit, and pain ratings were highest during the follow-up visit.

CONCLUSIONS

The sAA levels did not show the predicted increases during the surgery visit compared with the consult and postsurgical follow-up visits or increases during the surgery visit. However, individuals who reported responding to pain with helplessness had higher sAA levels in anticipation of surgery, providing proof of concept for the value of point-of-care assessments of surgery-induced stresses and the differential effect of personality traits.

Aspects on the integrative actions of the brain from neural networks to "brain-body medicine"

"Integration" is a key term in describing how nervous system can perform high level functions. A first condition to have "integration" is obviously the presence of efficient "communication processes" among the parts that have to be combined into the harmonious whole. In this respect, two types of communication processes, called wiring transmission (WT) and volume transmission (VT), respectively, were found to play a major role in the nervous system, allowing the exchange of signals not only between neurons, but rather among all cell types present in the central nervous system (CNS). A second fundamental aspect of a communication process is obviously the recognition/decoding process at target level. As far as this point is concerned, increasing evidence emphasizes the importance of supramolecular complexes of receptors (the so called receptor mosaics) generated by direct receptor-receptor interactions. Their assemblage would allow a first integration of the incoming information already at the plasma membrane level. Recently, evidence of two new subtypes of WT and VT has been obtained, namely the tunnelling nanotubes mediated WT and the microvesicle (in particular exosomes) mediated VT allowing the horizontal transfer of bioactive molecules, including receptors, RNAs and micro-RNAs. The physiological and pathological implications of these types of communication have opened up a new field that is largely still unexplored. In fact, likely unsuspected integrative actions of the nervous system could occur. In this context, a holistic approach to the brain-body complex as an indissoluble system has been proposed. Thus, the hypothesis has been introduced on the existence of a brain-body integrative structure formed by the "area postrema/nucleus tractus solitarius" (AP/NTS) and the "anteroventral third ventricle region/basal hypothalamus with the median eminence" (AV3V-BH). These highly interconnected regions operate as specialized interfaces between the brain and the body integrating brain-borne and body-borne neural and humoral signals.

Ventromedial prefrontal-subcortical systems and the generation of affective meaning

The ventromedial prefrontal cortex (vmPFC) comprises a set of interconnected regions that integrate information from affective sensory and social cues, long-term memory, and representations of the 'self'. Alhough the vmPFC is implicated in a variety of seemingly disparate processes, these processes are organized around a common theme. The vmPFC is not necessary for affective responses per se, but is critical when affective responses are shaped by conceptual information about specific outcomes. The vmPFC thus functions as a hub that links concepts with brainstem systems capable of coordinating organism-wide emotional behavior, a process we describe in terms of the generation of affective meaning, and which could explain the common role played by the vmPFC in a range of experimental paradigms.

The placebo effect: advances from different methodological approaches

There is accumulating evidence from different methodological approaches that the placebo effect is a neurobiological phenomenon. Behavioral, psychophysiological, and neuroimaging results have largely contributed to accepting the placebo response as real. A major aspect of recent and future advances in placebo research is to demonstrate linkages between behavior, brain, and bodily responses. This article provides an overview of the processes involved in the formation of placebo responses by combining research findings from behavioral, psychophysiological, and neuroimaging methods. The integration of these different methodological approaches is a key objective, motivating our scientific pursuits toward a placebo research that can inform and guide important future scientific knowledge.

A meta-analysis of heart rate variability and neuroimaging studies: implications for heart rate variability as a marker of stress and health

The intimate connection between the brain and the heart was enunciated by Claude Bernard over 150 years ago. In our neurovisceral integration model we have tried to build on this pioneering work. In the present paper we further elaborate our model and update it with recent results. Specifically, we performed a meta-analysis of recent neuroimaging studies on the relationship between heart rate variability and regional cerebral blood flow. We identified a number of regions, including the amygdala and ventromedial prefrontal cortex, in which significant associations across studies were found. We further propose that the default response to uncertainty is the threat response and may be related to the well known negativity bias. Heart rate variability may provide an index of how strongly 'top-down' appraisals, mediated by cortical-subcortical pathways, shape brainstem activity and autonomic responses in the body. If the default response to uncertainty is the threat response, as we propose here, contextual information represented in 'appraisal' systems may be necessary to overcome this bias during daily life. Thus, HRV may serve as a proxy for 'vertical integration' of the brain mechanisms that guide flexible control over behavior with peripheral physiology, and as such provides an important window into understanding stress and health.

Inflammation and cardiorespiratory control: the role of the vagus nerve

Inflammation and immunity have been implicated in a wide variety of diseases and disorders ranging from asthma to cardiovascular disease to hemorrhagic shock. In this review we will briefly consider the evidence for the neural concomitants of immunomodulation. First, we will briefly review the anatomy and physiology of the cardiorespiratory system. Then we will review the anatomy and physiology of neural-immune communication. The nucleus of the solitary tract is a site of integration of both the afferent and efferent neural regulation of the cardiorespiratory as well as the immune system. Then we will provide an overview of what is known about neuroimmunomodulation from both animal and human studies including neuroimaging and clinical studies. Finally, we will discuss a possible role of this neural circuitry in asthma related health disparities.

Predicting individual differences in placebo analgesia: contributions of brain activity during anticipation and pain experience

Recent studies have identified brain correlates of placebo analgesia, but none have assessed how accurately patterns of brain activity can predict individual differences in placebo responses. We reanalyzed data from two fMRI studies of placebo analgesia (N = 47), using patterns of fMRI activity during the anticipation and experience of pain to predict new subjects' scores on placebo analgesia and placebo-induced changes in pain processing. We used a cross-validated regression procedure, LASSO-PCR, which provided both unbiased estimates of predictive accuracy and interpretable maps of which regions are most important for prediction. Increased anticipatory activity in a frontoparietal network and decreases in a posterior insular/temporal network predicted placebo analgesia. Patterns of anticipatory activity across the cortex predicted a moderate amount of variance in the placebo response (∼12% overall, ∼40% for study 2 alone), which is substantial considering the multiple likely contributing factors. The most predictive regions were those associated with emotional appraisal, rather than cognitive control or pain processing. During pain, decreases in limbic and paralimbic regions most strongly predicted placebo analgesia. Responses within canonical pain-processing regions explained significant variance in placebo analgesia, but the pattern of effects was inconsistent with widespread decreases in nociceptive processing. Together, the findings suggest that engagement of emotional appraisal circuits drives individual variation in placebo analgesia, rather than early suppression of nociceptive processing. This approach provides a framework that will allow prediction accuracy to increase as new studies provide more precise information for future predictive models.

Neural aspects of immunomodulation: focus on the vagus nerve

Inflammation and immunity have been implicated in a wide variety of diseases and disorders ranging from Alzheimer's disease to cardiovascular disease to hemorrhagic shock. In this review, we will briefly consider the evidence for the neural concomitants of immunomodulation. First, we will briefly review the anatomy and physiology of neural-immune communication. Evidence for the somatotopic organization of the vagus nerve and for pain processes suggests that such an organization may be relevant for the investigation of the neural concomitants of immunity. Then we will provide an overview of what is known from both animal and human studies including neuroimaging and clinical studies. Finally, we will discuss some of the challenges and opportunities in this exciting area of investigation.

Allostasis and the human brain: Integrating models of stress from the social and life sciences

We draw on the theory of allostasis to develop an integrative model of the current stress process that highlights the brain as a dynamically adapting interface between the changing environment and the biological self. We review evidence that the core emotional regions of the brain constitute the primary mediator of the well-established association between stress and health, as well as the neural focus of wear and tear due to ongoing adaptation. This mediation, in turn, allows us to model the interplay over time between context, current stressor exposure, internal regulation of bodily processes, and health outcomes. We illustrate how this approach facilitates the integration of current findings in human neuroscience and genetics with key constructs from stress models from the social and life sciences, with implications for future research and the design of interventions targeting individuals at risk.