Allostasis, amygdala, and anticipatory angst

A preliminary investigation of worry, cortical amyloid burden, and stressor-evoked brain and cardiovascular reactivity in older adults

Worry is a transdiagnostic symptom common to many neurocognitive disorders of aging, including early stages of Alzheimer's disease and related dementias (ADRD). Severe worry is associated with amyloid burden in cognitively intact older adults, yet the mechanisms underlying this association are not well understood. We hypothesize that this relationship involves altered brain and cardiovascular reactivity to acute stressors, a brain-body phenotype that also increases risk for cardiovascular disease. Twenty cognitively normal older adults (age 60 to 80) with varying levels of worry severity underwent positron emission tomography using Pittsburgh Compound-B and functional magnetic resonance imaging. We examined associations of worry severity and amyloid burden with cardiovascular reactivity, brain activation, and brain connectivity using a cognitive stressor task. Worry severity was not associated with global amyloid burden, but was associated with greater resting levels of cardiovascular physiology and lower systolic blood pressure reactivity. Worry severity also was associated with altered stressor-evoked activation and effective connectivity in brain circuits implicated in stress processing, emotion perception, and physiological regulation. These associations showed small to medium effect sizes. These preliminary findings introduce key components of a model that may link severe worry to ADRD risk via stressor-evoked brain-body interactions.

Effects of cortisol administration on heart rate variability and functional connectivity across women with different depression histories

Abnormalities within the hypothalamic-pituitary-adrenal (HPA) axis and autonomic nervous system have been implicated in depression. Studies have reported glucocorticoid insensitivity and reduced heart rate variability (HRV) in depressive disorders. However, little is known about the effects of cortisol on HRV and resting-state functional connectivity (rsFC) of the central autonomic network (CAN) in depression. We collected resting-state fMRI and cardiac data for women with different depression histories (n = 61) after administration of cortisol and placebo using a double-blind crossover design. We computed rsFC for R-amygdala and L-amygdala seeds and assessed the change in HRV after cortisol (cortisol-placebo). Analyses examined the effects of acute cortisol administration on HRV and rsFC of the R-amygdala and L-amygdala. There was a significant interaction between HRV and treatment for rsFC between the amygdala and CAN regions. We found lower rsFC between the L-amygdala and putamen for those with a greater decrease in HRV after cortisol. There was also reduced rsFC between the R-amygdala and dorsomedial prefrontal cortex, putamen, middle cingulate cortex, insula, and cerebellum in those with lower HRV after cortisol. These results remained significant after adjusting for depression symptoms, age, and race. Our findings suggest that the effect of cortisol on CAN connectivity is related to its effects on HRV. Overall, these results could inform transdiagnostic interventions targeting HRV and the stress response systems across clinical and non-clinical populations.

Neuroplasticity of the extended amygdala in opioid withdrawal and prolonged opioid abstinence

Opioid use disorder is characterized by excessive use of opioids, inability to control its use, a withdrawal syndrome upon discontinuation of opioids, and long-term likelihood of relapse. The behavioral stages of opioid addiction correspond with affective experiences that characterize the opponent process view of motivation. In this framework, active involvement is accompanied by positive affective experiences which gives rise to "reward craving," whereas the opponent process, abstinence, is associated with the negative affective experiences that produce "relief craving." Relief craving develops along with a hypersensitization to the negatively reinforcing aspects of withdrawal during abstinence from opioids. These negative affective experiences are hypothesized to stem from neuroadaptations to a network of affective processing called the "extended amygdala." This negative valence network includes the three core structures of the central nucleus of the amygdala (CeA), the bed nucleus of the stria terminalis (BNST), and the nucleus accumbens shell (NAc shell), in addition to major inputs from the basolateral amygdala (BLA). To better understand the major components of this system, we have reviewed their functions, inputs and outputs, along with the associated neural plasticity in animal models of opioid withdrawal. These models demonstrate the somatic, motivational, affective, and learning related models of opioid withdrawal and abstinence. Neuroadaptations in these stress and motivational systems are accompanied by negative affective and aversive experiences that commonly give rise to relapse. CeA neuroplasticity accounts for many of the aversive and fear-related effects of opioid withdrawal via glutamatergic plasticity and changes to corticotrophin-releasing factor (CRF)-containing neurons. Neuroadaptations in BNST pre-and post-synaptic GABA-containing neurons, as well as their noradrenergic modulation, may be responsible for a variety of aversive affective experiences and maladaptive behaviors. Opioid withdrawal yields a hypodopaminergic and amotivational state and results in neuroadaptive increases in excitability of the NAc shell, both of which are associated with increased vulnerability to relapse. Finally, BLA transmission to hippocampal and cortical regions impacts the perception of conditioned aversive effects of opioid withdrawal by higher executive systems. The prevention or reversal of these varied neuroadaptations in the extended amygdala during opioid withdrawal could lead to promising new interventions for this life-threatening condition.

The relationship between perseverative thinking, proactive control, and inhibition in psychological distress: a study in a women's cohort

Cognitive control is a core feature of several mental disorders. A recent account poses that health problems may derive from proactive forms of cognitive control that maintain stress representation over time. The working hypothesis of the present study is that psychological distress is caused by the tendency to select a particular maladaptive self-regulation strategy over time, namely perseverative thinking, rather than by transient stimulus-response patterns. To test this hypothesis, we asked 84 women to carry out a battery of standardized questionnaires regarding their tendency to undertake perseverative thinking and their level of psychological distress, followed by cognitive tasks measuring the tendency to use proactive versus reactive control modality and disinhibition. Through a series of mediation analyses, we demonstrate that the tendency to use proactive control correlates with psychological distress and that this relation is mediated by perseverative thinking. Moreover, we show that the relation between low inhibitory control and psychological stress is more strongly mediated by perseverative thinking than impulsiveness, a classical construct that focuses on more transient reactions to stimuli. The present results underline the importance of considering psychological distress as the consequence of a maladaptive way of applying control over time, rather than the result of a general deficit in cognitive control abilities.

Suicide: Allostatic regulation and resilience

Suicide is a complex public health problem that is the result of a number of intertwined biopsychosocial factors. The diathesis-stress model suggests that suicide is the result of an interaction between genetic vulnerability and environmental stressors. Chronic stress and trauma contribute to biologic adaptations, including hypothalamus-pituitary-adrenal axis dysregulation, that contribute to the degradation of regulatory mechanisms and promote wear and tear the body, represented by allostatic load (AL). AL has been associated with a number of negative outcomes, including mental health problems and suicide. Fortunately, there are pharmacological and non-pharmacological interventions that are effective at reducing AL and reversing its effects. Thus, AL may provide a construct for supporting early risk identification, prevention, and treatment of suicide. AL biomarkers that are amenable to measurable change, effective treatments to reduce AL and perhaps help prevent suicide, and how to best tailor them to the individual and societal levels are important avenues of therapeutic inquiry.

Hormone and enzyme reactivity before, during, and after a music performance: Cortisol, testosterone, and alpha-amylase

Performance anxiety is common in a wide range of settings. This study was designed to explore the hormonal correlates of a music performance recital – a setting commonly associated with extreme and often unsettling anxiety linked to the anticipation of performing. Thirty-nine college undergraduate participants (24 women and 15 men) were recruited from students enrolled in an undergraduate music performance course. Each gave a saliva sample on a neutral non-performance day and gave additional samples immediately before and 10 and 30-min after each of two solo music recitals. Samples were subsequently assayed for cortisol, alpha-amylase, and testosterone. For women, pre-performance salivary cortisol levels were significantly elevated relative to neutral-day baseline (presumably in anticipation of performing) and continued to rise in association with the performance phase of the recital. Pre-performance alpha-amylase was significantly higher than neutral-day baseline. Testosterone increased in connection with the performance phase of the recital, but not during the anticipation phase. For all three products, patterns for men were generally similar to those for women, though not as statistically robust, perhaps owing to the smaller sample size. Increases in cortisol and alpha-amylase, from neutral-day to immediately pre-performance on recital day, suggest an effect related to the psychological anticipation of the recital. Cortisol and testosterone (but not alpha-amylase) increased in association with the performance phase of the recital. Phase-related changes in these products appears to reflect a coordinated response to the stress of a music recital and perhaps, more generally, to social-evaluative threat.

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Salivary cortisol, alpha-amylase, and testosterone increase in association with a music recital.

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Cortisol and alpha-amylase increase in anticipation of the performance phase.

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Cortisol and testosterone increase during the performance phase.

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Cortisol/Testosterone coupling increases testosterone reactivity in this setting.

Depression Mediates the Association Between Childhood Emotional Abuse and the Onset of Type 2 Diabetes: Findings From German Multi-Cohort Prospective Studies

BACKGROUND

The dysregulation of glucose homeostasis via mental health stress is increasingly acknowledged, whereby depression independently increases the risk of the onset of type 2 diabetes by up to 60%. Contributing mental health factors starting in early life have further been considered, indicating that exposure to childhood emotional abuse is associated with both depression and an increased onset of type 2 diabetes in adulthood. However, the potential role of depression within the emotional abuse and type 2 diabetes link remains unknown.

METHODS

Data were derived from community-dwelling participants in southern and northeastern Germany who participated in the longitudinal KORA-F4 and SHIP-3 studies. Multivariable logistic regression analyses adjusted for lifestyle, somatic, and psychological risk factors were used to investigate the association between childhood emotional abuse, assessed retrospectively by the Childhood Trauma Screener, and newly diagnosed type 2 diabetes cases, which were confirmed using a standard oral glucose tolerance test. The mediating role of depressive symptoms between childhood emotional abuse and type 2 diabetes was assessed by the Patient Health Questionnaire-9 and calculated by using the Sobel test for mediation.

RESULTS

A total of 2,973 (53.2% women, 46.8% men) participants with a mean age of 49.7 were included in the analyses, of whom 5.9% (7.1% women, 4.5% men) reported emotional abuse in childhood. Participants exposed to childhood emotional abuse had a 1.70 (1.12-2.56; p = 0.02) times higher odds of depression in the fully adjusted model than unexposed participants. During the 6.5-year follow-up period, 104 (3.5%) participants developed type 2 diabetes. Participants who were exposed to childhood emotional abuse had a 2.56 (1.31-4.98, p = 0.005) times higher odds of developing type 2 diabetes than unexposed participants. This association was significantly mediated by the increased odds of depression in participants with childhood emotional abuse (Sobel Test, 1.84, p = 0.06; Goodman Test, 1.91, p = 0.05).

CONCLUSION

The current results indicate that the increased likelihood of type 2 diabetes onset in participants who were exposed to childhood emotional abuse is significantly attributed to increased depression in adulthood.

Exploring the Relationship Between Social Ties and Resilience From Evolutionary Framework

This conceptual paper examines the necessity and importance of social bonds and networks in building resilience to fight the COVID-19. Resilience is a quality that energizes an individual’s actions and acts as a buffer to stressful events. The current article is intended to explore the evolutionary programmed behavior of the human mind to make social ties and structure. Humans have a strong need to connect and relate with other individuals by developing cooperation and perspective-taking. The ability to make social connections, group living, and sharing resources had a selective advantage in coping with physical and psychological stress. Social bonds provide resilience to people’s approach while making adjustments and adapting to situations, thus presents fitness benefits at both group and individual levels. An attempt has also been made to address how social isolation as a strategy to contain the infection adversely influence body homeostasis. Finally, this article recommends health practitioners, clinicians, and researchers to encourage research on the impact of social isolation/social interaction on mental and physical health indicators.

Cortisol response to stress: The role of expectancy and anticipatory stress regulation

An exacerbated physiological response to stress is associated with the development of stress-related disorders (e.g., depression and anxiety disorders). Recently, it has been proposed that individuals with high expectancies of being able to deal with stressful situations will activate regulatory mechanisms during the anticipation of the stressful event that would improve stress regulation. To test this hypothesis, 52 women in young adulthood (M = 21.06; SD = 2.58) anticipated and performed a laboratory-based stress task after receiving positive or negative bogus feedback on their abilities to deal with stressful events. Heart rate variability and salivary cortisol were assessed throughout the experimental protocol. Participants receiving positive bogus feedback (i.e., High Expectancy group) showed a more positive anticipatory cognitive stress appraisal (i.e., they anticipated the stress task as less threatening/challenging, and they perceived that they were more able to deal with it), and they showed a lower cortisol response to stress. Moreover, a more positive anticipatory cognitive stress appraisal was associated with better anticipatory stress regulation (indexed as less decrease in heart rate variability), leading to a lower cortisol response. Our results indicate that people with positive expectancy initiate mechanisms of anticipatory stress regulation that enhance the regulation of the physiological stress response. Expectancy and anticipatory stress regulation may be key mechanisms in the development and treatment of stress-related disorders.

A Computational Theory of Mindfulness Based Cognitive Therapy from the "Bayesian Brain" Perspective

Mindfulness Based Cognitive Therapy (MBCT) was developed to combine methods from cognitive behavioral therapy and meditative techniques, with the specific goal of preventing relapse in recurrent depression. While supported by empirical evidence from multiple clinical trials, the cognitive mechanisms behind the effectiveness of MBCT are not well understood in computational (information processing) or biological terms. This article introduces a testable theory about the computational mechanisms behind MBCT that is grounded in "Bayesian brain" concepts of perception from cognitive neuroscience, such as predictive coding. These concepts regard the brain as embodying a model of its environment (including the external world and the body) which predicts future sensory inputs and is updated by prediction errors, depending on how precise these error signals are. This article offers a concrete proposal how core concepts of MBCT-(i) the being mode (accepting whatever sensations arise, without judging or changing them), (ii) decentering (experiencing thoughts and percepts simply as events in the mind that arise and pass), and (iii) cognitive reactivity (changes in mood reactivate negative beliefs)-could be understood in terms of perceptual and metacognitive processes that draw on specific computational mechanisms of the "Bayesian brain." Importantly, the proposed theory can be tested experimentally, using a combination of behavioral paradigms, computational modelling, and neuroimaging. The novel theoretical perspective on MBCT described in this paper may offer opportunities for finessing the conceptual and practical aspects of MBCT.

Effect of music therapy on anxiety levels on patient undergoing dental extractions

BACKGROUND AND AIMS

Dental anxiety has been found to be a significant problem faced by patients undergoing extractions. Anxious patients tend to avoid dental care ultimately leading to complications. Treatment of anxious patients can be very challenging to the dentists, prolonging the treatment duration. There has been various methods to reduce anxiety of which non pharmacological ways include music and aroma therapy. Music has been known to reduce fear, stress and is a form of meditation and relaxation. Hence effect of music on the reduction of anxiety levels for patients undergoing extractions were assessed. The aim of this study is to assess the effect of music therapy on dental anxiety levels of patients undergoing extractions.

METHODS

50 patients visiting the outpatient department of Saveetha Dental College for dental extractions were randomly selected and allocated to Test group and Control group. The test group (N = 25) were subjected to music during extractions and Control (N = 25) were not exposed. Dental anxiety levels and hemodynamic changes namely systolic pressure, diastolic pressure and heart rate were assessed before and after extraction. The data was collected and analyzed using SPSS software with Paired t Test.

RESULTS

The study showed that the control population had elevated hemodynamic changes with regard to systolic, diastolic blood pressure and heart rate, of which the diastolic pressure rise was significant. In the test population, there was fall in the hemodynamic changes with respect to systolic diastolic blood pressure and heart rate, all of which were statistically significant. This was evident in the modified dental anxiety scale as well.

CONCLUSION

Music seems to be a psychological and spiritual way to calm oneself down. Hence music therapy can be used as an anxiolytic agent for stressful dental procedures.

Early Attachment Disruption, Inflammation, and Vulnerability for Depression in Rodent and Primate Models

Early experiments in nonhuman primates established the relation between disruption of filial attachment and depressive-like outcomes. Subsequent studies in rats and mice have been instrumental in linking depressive-like outcomes to disturbances in maternal behavior. Another aspect of attachment disruption, absence of the attachment object per se, may be studied more effectively in a different laboratory rodent-the guinea pig. Here, we discuss the rationale for using guinea pigs for this work. We then review guinea pig studies providing evidence for inflammatory mechanisms mediating both depressive-like behavior during separation as well as sensitization of stress responsiveness such as is thought to lead to increased vulnerability to depression at later ages. Finally, we discuss recent complementary work in adult monkeys that suggests cross-species generalizability of broad principles derived from the guinea pig experiments. Overall, the findings provide experimental support for human research implicating inflammatory mechanisms in the development of increased stress responsiveness and vulnerability to depression following attachment disruption and other forms of early-life stress. Specifically, the findings suggest inflammatory mechanisms may set in motion a cascade of underlying processes that mediate later increased stress responsiveness and, therefore, depression susceptibility.

A Longitudinal Study of Allostatic Load in Later Life: The Role of Sex, Birth Cohorts, and Risk Accumulation

Are challenging life courses associated with more wear and tear on the biological level? This study investigates this question from a life-course perspective by examining the influence of life-course risk accumulation on allostatic load (AL), considering the role of sex and birth cohorts. Using biomarker data collected over three waves (2004, 2008, and 2012) of the English Longitudinal Study of Ageing ( N = 3,824) in a growth curve framework, AL trajectories over a period of 8 years are investigated. Our results illustrate that AL increases substantially in later life. Men have higher AL than women, but increases are similar for both sexes. Older cohorts have both higher levels and a steeper increase of AL over time. Higher risk accumulation over the life course goes hand in hand with higher AL levels and steeper trajectories, contributing to the body of evidence on cumulative (dis)advantage processes in later life.

Acupuncture on the Stress-Related Drug Relapse to Seeking

Drug addiction is a chronic relapsing disease, which causes serious social and economic problems. The most important trial for the successful treatment of drug addiction is to prevent the high rate of relapse to drug-seeking behaviors. Opponent process as a motivational theory with excessive drug seeking in the negative reinforcement of drug dependence reflects both loss of brain reward system and recruitment of brain stress system. The negative emotional state produced by brain stress system during drug withdrawal might contribute to the intense drug craving and drive drug-seeking behaviors via negative reinforcement mechanisms. Decrease in dopamine neurotransmission in the nucleus accumbens and recruitment of corticotropin-releasing factor in the extended amygdala are hypothesized to be implicated in mediating this motivated behavior. Also, a brain stress response system is hypothesized to increase drug craving and contribute to relapse to drug-seeking behavior during the preoccupation and anticipation stage of dependence caused by the exposure to stress characterized as the nonspecific responses to any demands on the body. Acupuncture has proven to be effective for reducing drug addiction and stress-related psychiatric disorders, such as anxiety and depression. Furthermore, acupuncture has been shown to correct reversible brain malfunctions by regulating drug addiction and stress-related neurotransmitters. Accordingly, it seems reasonable to propose that acupuncture attenuates relapse to drug-seeking behavior through inhibition of stress response. In this review, a brief description of stress in relapse to drug-seeking behavior and the effects of acupuncture were presented.

Hypothalamic CNTF volume transmission shapes cortical noradrenergic excitability upon acute stress

Stress-induced cortical alertness is maintained by a heightened excitability of noradrenergic neurons innervating, notably, the prefrontal cortex. However, neither the signaling axis linking hypothalamic activation to delayed and lasting noradrenergic excitability nor the molecular cascade gating noradrenaline synthesis is defined. Here, we show that hypothalamic corticotropin-releasing hormone-releasing neurons innervate ependymal cells of the 3rd ventricle to induce ciliary neurotrophic factor (CNTF) release for transport through the brain's aqueductal system. CNTF binding to its cognate receptors on norepinephrinergic neurons in the locus coeruleus then initiates sequential phosphorylation of extracellular signal-regulated kinase 1 and tyrosine hydroxylase with the Ca2+-sensor secretagogin ensuring activity dependence in both rodent and human brains. Both CNTF and secretagogin ablation occlude stress-induced cortical norepinephrine synthesis, ensuing neuronal excitation and behavioral stereotypes. Cumulatively, we identify a multimodal pathway that is rate-limited by CNTF volume transmission and poised to directly convert hypothalamic activation into long-lasting cortical excitability following acute stress.

Maternal Cerebrospinal Fluid Glutamate in Response to Variable Foraging Demand: Relationship to Cerebrospinal Fluid Serotonin Metabolites in Grown Offspring

Background

Maternal response to allostatic overload during infant rearing may alter neurobiological measures in grown offspring, potentially increasing susceptibility to mood and anxiety disorders. We examined maternal cerebrospinal fluid (CSF) glutamate response during exposure to variable foraging demand (VFD), a bonnet macaque model of allostatic overload, testing whether activation relative to baseline predicted concomitant CSF elevations of the stress neuropeptide, corticotropin-releasing factor. We investigated whether VFD-induced activation of maternal CSF glutamate affects maternal–infant attachment patterns and offspring CSF 5-hydroxyindoleacetic acid concentrations.

Methods

Mother–infant dyads were exposed to the “VFD stressor,” a paradigm in which mothers experience 16 weeks of foraging uncertainty while rearing their infant offspring. Through staggering the infant age of VFD onset, both a cross-sectional design and a longitudinal design were used. Maternal CSF glutamate and glutamine concentrations post-VFD exposure were cross-sectionally compared to maternal VFD naive controls. Proportional change in concentrations of maternal glutamate (and glutamine), a longitudinal measure, was evaluated in relation to VFD-induced elevations of CSF corticotropin-releasing factor. The former measure was related to maternal–infant proximity scores obtained during the final phases of VFD exposure. Maternal glutamatergic response to VFD exposure was used as a predictor variable for young adolescent offspring CSF metabolites of serotonin, dopamine, and norepinephrine.

Results

Following VFD exposure, maternal CSF glutamate concentrations correlated positively with maternal CSF CRF concentrations. Activation relative to baseline of maternal CSF glutamate concentrations following VFD exposure correlated directly with a) increased maternal-infant proximity during the final phases of VFD and b) offspring CSF concentrations of monoamine metabolites including 5-hydroxyindoleacetic acid, which was elevated relative to controls.

Conclusions

Activation of maternal CSF glutamate in response to VFD-induced allostasis is directly associated with elevations of maternal CSF corticotropin-releasing factor. Maternal CSF glutamate alterations induced by VFD potentially compromise serotonin neurotransmission in grown offspring, conceivably modeling human vulnerability to treatment-resistant mood and anxiety disorders.

Association between changes in heart rate variability during the anticipation of a stressful situation and the stress-induced cortisol response

Vagal activity - reflecting the activation of stress regulatory mechanisms and prefrontal cortex activation - is thought to play an inhibitory role in the regulation of the hypothalamus-pituitary-adrenal axis. However, most studies investigating the association between stress-induced changes in heart rate variability (HRV, an index of cardiac vagal tone) and cortisol have shown a non-significant relationship. It has been proposed that physiological changes observed during anticipation of a stressor allow individuals to make behavioral, cognitive, and physiological adjustments that are necessary to deal with the upcoming actual stressor. In this study, in a large sample of 171 healthy adults (96 men and 75 women; mean age = 29.98, SD = 11.07), we investigated whether the cortisol response to a laboratory-based stress task was related to anticipation-induced or stress task-induced changes in HRV. As expected, regression analyses showed that a larger decrease in HRV during the anticipation of a stress task was related to higher stress task-induced cortisol increase, but not cortisol recovery. In line with prior research, the stress task-induced change in HRV was not significantly related to cortisol increase or recovery. Our results show for the first time that anticipatory HRV (reflecting differences in stress regulation and prefrontal activity before the encounter with the stressor) is important to understand the stress-induced cortisol increase.

A Comprehensive Overview on Stress Neurobiology: Basic Concepts and Clinical Implications

Stress is recognized as an important issue in basic and clinical neuroscience research, based upon the founding historical studies by Walter Canon and Hans Selye in the past century, when the concept of stress emerged in a biological and adaptive perspective. A lot of research after that period has expanded the knowledge in the stress field. Since then, it was discovered that the response to stressful stimuli is elaborated and triggered by the, now known, stress system, which integrates a wide diversity of brain structures that, collectively, are able to detect events and interpret them as real or potential threats. However, different types of stressors engage different brain networks, requiring a fine-tuned functional neuroanatomical processing. This integration of information from the stressor itself may result in a rapid activation of the Sympathetic-Adreno-Medullar (SAM) axis and the Hypothalamus-Pituitary-Adrenal (HPA) axis, the two major components involved in the stress response. The complexity of the stress response is not restricted to neuroanatomy or to SAM and HPA axes mediators, but also diverge according to timing and duration of stressor exposure, as well as its short- and/or long-term consequences. The identification of neuronal circuits of stress, as well as their interaction with mediator molecules over time is critical, not only for understanding the physiological stress responses, but also to understand their implications on mental health.

Brain-heart interaction in perseverative cognition

The move from the concept of homeostasis to that of allostasis has led reactivity stress research to widen the object of its investigation: from the brief physiological response that occurs when one is facing a stressor to what happens when one is anticipating or recovering from a stressor. A paradigmatic example is represented by perseverative cognition, during which human beings react "as if" they were constantly facing a concrete stressor. The core idea behind this review is that the cognitive inflexibility that characterizes perseverative cognition is reflected in both our body (by increased autonomic nervous system rigidity assessed by heart rate variability; HRV) and our brain (by reduced prefrontal-amygdala functional connectivity). This is a review of studies conducted in different settings (laboratory, daily life), populations (healthy, major depression, generalized anxiety), location (United States, Europe), and age groups (children, adults) that consistently replicated the association between autonomic, subjective, and behavioral measures of cognitive inflexibility during perseverative cognition. Moreover, compelling neuroimaging data suggest that HRV reduction from pre- to post-induction of perseverative cognition is associated with both structural and functional brain abnormalities reflecting impaired prefrontal inhibitory control over subcortical structures (e.g., diminished prefrontal-amygdala functional connectivity). The integration of neuroscience techniques with clinical autonomic research has advanced our understanding of the neurobiology of brain-heart interaction during perseverative cognition, potentially yielding to more effective treatment packages. This is clinically relevant if one considers that perseverative cognition is a pervasive transdiagnostic factor that carries prognostic risk for both psychological and somatic health.

Mechanisms of Stress-induced Visceral Pain

Evidence suggests that long-term stress facilitates visceral pain through sensitization of pain pathways and promotes chronic visceral pain disorders such as the irritable bowel syndrome (IBS). This review will describe the importance of stress in exacerbating IBS-induced abdominal pain. Additionally, we will briefly review our understanding of the activation of the hypothalamic-pituitary-adrenal axis by both chronic adult stress and following early life stress in the pathogenesis of IBS. The review will focus on the glucocorticoid receptor and corticotropin-releasing hormone-mediated mechanisms in the amygdala involved in stress-induced visceral hypersensitivity. One potential mechanism underlying persistent effects of stress on visceral sensitivity could be epigenetic modulation of gene expression. While there are relatively few studies examining epigenetically mediated mechanisms involved in stress-induced visceral nociception, alterations in DNA methylation and histone acetylation patterns within the brain, have been linked to alterations in nociceptive signaling via increased expression of pro-nociceptive neurotransmitters. This review will discuss the latest studies investigating the long-term effects of stress on visceral sensitivity. Additionally, we will critically review the importance of experimental models of adult stress and early life stress in enhancing our understanding of the basic molecular mechanisms of nociceptive processing.

Corticotropin-Releasing Factor (CRF) and Addictive Behaviors

Drug addiction is a complex disorder that is characterized by compulsivity to seek and take the drug, loss of control in limiting intake of the drug, and emergence of a withdrawal syndrome in the absence of the drug. The transition from casual drug use to dependence is mediated by changes in reward and brain stress functions and has been linked to a shift from positive reinforcement to negative reinforcement. The recruitment of brain stress systems mediates the negative emotional state produced by dependence that drives drug seeking through negative reinforcement mechanisms, defined as the "dark side" of addiction. In this chapter we focus on behavioral and cellular neuropharmacological studies that have implicated brain stress systems (i.e., corticotropin-releasing factor [CRF]) in the transition to addiction and the predominant brain regions involved. We also discuss the implication of CRF recruitment in compulsive eating disorders.

Infant stranger fear trajectories predict anxious behaviors and diurnal cortisol rhythm during childhood

Although a robust literature has linked stable, high levels of fear across childhood to increased risk for anxiety problems, less is known about alternative pathways to anxiety. We tested two putatively normative developmental pathways of early fearfulness for their distinct associations with behavioral (anxiety-related behaviors and symptoms) and biological (diurnal cortisol) markers of anxiety risk in middle childhood in a community-based sample (n = 107). Steeper increases in fear from 6 to 36 months predicted more parent-reported anxiety symptoms at age 8 years. In addition, children who exhibited steep increases in fear during infancy were overrepresented among children with diagnoses of separation anxiety disorder at age 8 years. Finally, we showed that steeper increases in fearfulness in infancy predicted flatter slopes of diurnal cortisol at age 8 years for girls. Thus, differences in stranger fear across infancy may indicate varying degrees of risk for anxious behaviors in later childhood.

Neural basis for the relationship between frequency of going outdoors and depressive mood in older adults

OBJECTIVE

Low frequency of going outdoors (e.g. being homebound) is associated with depressive mood; however, the underlying neural mechanism of this association is unclear. We therefore investigated the neural substrate involved in the relationship between frequency of going outdoors and depressive mood using positron emission tomography (PET), focusing on the frontal lobe and the limbic system.

METHODS

One hundred fifty-eight community-dwelling older adults aged 65-85 years underwent PET with ¹⁸ F-fluorodeoxyglucose to evaluate regional cerebral metabolic rates of glucose normalized in reference to cerebellar glucose metabolic value (normalized-rCMRglc) in six regions of interest. We also assessed depressive mood, frequency of going outdoors, and potential covariates. Depressive mood was assessed using the Geriatric Depression Scale (GDS).

RESULTS

The proportion of participants who reported low frequency of going outdoors (LG, every 2-3 days or less) was 36.1%. The LG group showed significantly higher GDS scores than those who reported high (once a day or more) frequency of going outdoors. A multiple linear regression analysis adjusted for potential covariates showed higher GDS scores were associated with lower normalized-rCMRglc in the ventrolateral prefrontal and orbitofrontal cortices. Adjusting for frequency of going outdoors, the association between GDS score and normalized-rCMRglc in the orbitofrontal cortex was attenuated.

CONCLUSIONS

Our results suggest that the orbitofrontal cortex may mediate the relationship between low frequency of going outdoors and depressive mood among community-dwelling older adults. These findings may help disentangle the role of going outdoors in regulating brain function to improve and/or maintain mental health among community-dwelling older adults. Copyright © 2016 John Wiley & Sons, Ltd.

Low temperatures during ontogeny increase fluctuating asymmetry and reduce maternal aggression in the house mouse, Mus musculus

Maternal aggression is behavior displayed by post-partum lactating female mice toward unfamiliar conspecifics, presumably as a defense against infanticide. A variety of perinatal stressors can impair maternal care in adulthood. Previous studies on associations between developmental perturbations and maternal aggression have produced mixed results. To address this issue, we employed a proxy for developmental instability, fluctuating asymmetry (FA) to further elucidate the relationship between low temperature stress and maternal aggression. FA, small, random deviations from perfect symmetry in bilateral characters is used as a quantitative measure of stress during ontogeny. Dams were either maintained in standard laboratory temperatures (21 ± 2 °C), or cold temperatures (8 ± 2 °C) during gestation. During lactation, their progeny either remained in the temperature condition in which they were gestated or were transferred to the other temperature condition. Four individual measures of FA, a composite of these measures, and three measures of maternal aggression were assessed in the female progeny in adulthood. Exposure to low temperatures during both pre- and early post-natal development increased composite FA and reduced all three measures of maternal aggression compared to controls. Exposure to low temperatures during the pre- or postnatal period alone did not induce either high FA or altered maternal aggression. Certain measures of FA and nest defense were negatively correlated. Our results suggest that low temperatures experienced during gestation and lactation may have important fitness costs. Low maternal aggression towards infanticidal conspecifics is likely to limit the number of offspring surviving into adulthood. Overall, FA appears to be a reliable indicator of chronic developmental stress with implications for fitness.

Differences in Cortisol Response to Trauma Activation in Individuals with and without Comorbid PTSD and Depression

Background: Although depression symptoms are often experienced by individuals who develop posttraumatic stress disorder (PTSD) following trauma exposure, little is know about the biological correlates associated with PTSD and depression co-morbidity vs. those associated with PTSD symptoms alone.

Methods: Here we examined salivary cortisol responses to trauma activation in a sample of 60 survivors of the World Trade Center attacks on September 11, 2001. Participants recalled the escape from the attacks 7 months post 9/11. Salivary cortisol levels were measured before and after their recollection of the trauma. PTSD, depression, and somatic symptoms were also assessed. From the behavioral assessment scales, the participants were grouped into three conditions: those with comorbid PTSD and depressive symptoms, PTSD alone symptoms, or no-pathology.

Results: Baseline and cortisol response levels differed between the comorbid, PTSD alone, and no-pathology groups. Individuals endorsing co-morbid symptoms had higher PTSD and somatic symptom severity and their cortisol response decreased following their trauma reminder while a trend of an elevated response to the trauma was found in the PTSD alone group. Our findings show distinct psychological and biological correlates related to the endorsement of PTSD with and without depression comorbidity.

Conclusions: The findings suggest that comorbidity symptoms manifestation entails a separate trauma induced condition from PTSD. Future research on biological correlates of comorbid PTSD and depression is warranted.

Depressive-like behavior, its sensitization, social buffering, and altered cytokine responses in rhesus macaques moved from outdoor social groups to indoor housing

Psychosocial stressors appear to promote the onset of depressive illness through activation and sensitization of inflammatory mechanisms. Here, adult male rhesus monkeys brought from large outdoor social groups to indoor housing for 8 days reliably exhibited a hunched, depressive-like posture. When rehoused indoors a second 8 days about 2 weeks later, monkeys housed alone, but not those with an affiliative partner, showed sensitization of the depressive-like hunched posture. Housing indoors also affected circulating pro-inflammatory cytokines: IL-1β showed increased responsiveness to immune challenge, and IL-1β and TNF-α showed reduced suppression by dexamethasone. Sensitivity of the anti-inflammatory cytokine IL-10 to immune challenge exhibited a relative increase from the first to the second round of indoor housing in animals housed in pairs, and a relative decrease in animals housed alone. Cytokine levels during indoor housing were positively correlated with duration of depressive-like behavior. Plasma cortisol levels increased but did not differentiate housing conditions or rounds. Results demonstrate a rapid induction and sensitization of depressive-like behavior to indoor individual housing, social buffering of sensitization, and associated inflammatory responses. This paradigm may provide a practical nonhuman primate model for examining inflammatory-mediated consequences of psychosocial stressors on depression and possible social buffering of these effects.

Associations Among Academic Achievement, Attention, and Adrenocortical Reactivity in Caribbean Village Children

This study examined associations among academic achievement problems, attention problems, and cortisol levels in 86 children (ages 5 to 12) in St. Vincent, the West Indies. Findings revealed that morning cortisol levels were more elevated at school than at home. Attention problems contributed negatively to academic scores. Children with the most attention problems showed greater school relative to home cortisol elevations than did other children. Once the variance due to attention problems was accounted for, the interaction between attention problems and cortisol elevation explained additional variance in academic scores. There was some evidence that attention problems and cortisol reactivity were associated. Furthermore, greater cortisol reactivity was correlated with the academic difficulties of children who exhibited more attention problems.

Associations between bedtime and nighttime parenting and infant cortisol in the first year

We examined how maternal care within the bedtime and nighttime contexts influences infant cortisol levels and patterning. Eighty-two mothers (M_age  = 29.4 years) and infants participated in a longitudinal study when infants were 3, 6, and 9 months old. At each time point, bedtime and nighttime parenting were recorded and infant cortisol at bedtime and the following morning was analyzed. Multilevel model analyses showed that infants had lower cortisol levels when mothers were more emotionally available at bedtime, and infants whose mothers responded more often to their non-distressed cues had lower cortisol levels on average. Less co-sleeping and more maternal responses to infant distress were linked to healthier cortisol patterning. By shedding light on parenting qualities and behaviors that influence infant cortisol, these results indicate avenues for intervention and suggest the utility of studying parenting in infant sleep contexts.

The Effects of Outgroup Threat and Opportunity to Derogate on Salivary Cortisol Levels

Perceptions of intergroup threat have been related to both experiences of physiological stress responses and derogation of the outgroup. In this study, a neuroscience perspective was used to investigate the relationship between stress and opportunity to derogate the outgroup, in a threatening intergroup context. Research from a social identity perspective suggests that engaging in outgroup derogation alleviates stress when perceiving an intergroup threat. However, in line with the model of intergroup anxiety, opportunity to derogate could exacerbate the negative connotations of a threatening situation, resulting in more stress. Canadian participants (N = 110) were exposed to text describing either discriminatory or favorable comments expressed by Chinese individuals towards Canadians. Half of the participants were given the opportunity to derogate via a bias task. Salivary cortisol was used as a measure of stress and was collected at baseline, post-threat, and post-derogation. As expected, threatening identity led to more stress as evidenced by increased cortisol concentrations. Furthermore, threatened participants who had an opportunity to derogate showed greater cortisol concentrations than those who did not. These results demonstrate a link between stress and the opportunity to derogate, and highlights the value of using biological markers within the intergroup context. Rewrite abstract to remove all the references (they are meaningless because the abstracting services will use the abstract as is but will not provide the references so their presence is useless.

Dogs in Animal Shelters: Problems, Suggestions, and Needed Expertise

Because of very real practical constraints, conditions in animal shelters are often reminiscent of those in early primate deprivation studies. Dogs are frequently surrendered to shelters because of behavior problems, and aspects of the shelter environment may induce anomalous behavior, increasing the chances that adopted dogs will be returned to the shelters. Comparative psychologists, psychobiologists, and other behavioral scientists possess the knowledge and techniques to help shelters intervene in this cycle. Experience suggests human interaction and the application of basic conditioning procedures can reduce the impact of the shelter environment, and ease the transition into the adoptive home. A program developed to meet these goals is described. Shelters can provide opportunities both for the training of students in animal-related exercises and for limited applied research. Behavioral scientists stand in a unique position to help transform conditions in animal shelters to the benefit of all involved.

The role of the hypothalamus-pituitary-adrenal/interrenal axis in mediating predator-avoidance trade-offs

Maintaining energy balance and reproducing are important for fitness, yet animals have evolved mechanisms by which the hypothalamus-pituitary-adrenal/interrenal (HPA/HPI) axis can shut these activities off. While HPA/HPI axis inhibition of feeding and reproduction may have evolved as a predator defense, to date there has been no review across taxa of the causal evidence for such a relationship. Here we review the literature on this topic by addressing evidence for three predictions: that exposure to predators decreases reproduction and feeding, that exposure to predators activates the HPA/HPI axis, and that predator-induced activation of the HPA/HPI axis inhibits foraging and reproduction. Weight of evidence indicates that exposure to predator cues inhibits several aspects of foraging and reproduction. While the evidence from fish and mammals supports the hypothesis that predator cues activate the HPA/HPI axis, the existing data in other vertebrate taxa are equivocal. A causal role for the HPA axis in predator-induced suppression of feeding and reproduction has not been demonstrated to date, although many studies report correlative relationships between HPA activity and reproduction and/or feeding. Manipulation of HPA/HPI axis signaling will be required in future studies to demonstrate direct mediation of predator-induced inhibition of feeding and reproduction. Understanding the circuitry linking sensory pathways to their control of the HPA/HPI axis also is needed. Finally, the role that fear and anxiety pathways play in the response of the HPA axis to predator cues is needed to better understand the role that predators have played in shaping anxiety related behaviors in all species, including humans.

Effects of Music Listening on Pre-treatment Anxiety and Stress Levels in a Dental Hygiene Recall Population

BACKGROUND

Waiting for a medical procedure can exert significant feelings of state anxiety in patients. Music listening has been shown to be effective in decreasing anxiety levels. No study so far examined the potential anxiety and stress-reducing effect of a music intervention on pre-treatment anxiety and stress in patients waiting for dental hygiene treatment. Knowing whether the anxiety-reducing effect of music would also be detectible in the context of preventive routine medical procedures in healthy individuals would widen the area of application of music from the hospital or clinical environment to medical offices in general.

PURPOSE

Waiting for a medical treatment can induce anxiety and may lead to the experience of stress. We set out to examine the effect of music on pre-treatment anxiety in a healthy patient sample waiting for a dental treatment.

METHODS

In a randomized controlled clinical trial, 92 consecutive volunteer patients (mean age, 57 years) waiting for their scheduled dental hygiene treatment were randomly allocated to either an experimental (n = 46, listening to music for 10 min) or a control group (n = 46, waiting in silence). State and habitual anxiety, subjective stress, and mood measures were assessed before and after music listening or silence, respectively.

RESULTS

State anxiety levels in the music group decreased significantly after intervention as compared to the control group (F(1/90) = 8.06; p = 0.006). Participants' trait anxiety and dental anxiety were not found to moderate this effect.

CONCLUSIONS

Listening to music prior to dental hygiene treatment decreases anxiety levels to a greater extent than waiting in silence.

Epigenetic modulation of chronic anxiety and pain by histone deacetylation

Prolonged exposure of the central amygdala (CeA) to elevated corticosteroids (CORT) facilitates long-term anxiety and pain through activation of glucocorticoid receptors (GRs) and corticotropin-releasing factor (CRF). However, the mechanisms maintaining these responses are unknown. Since chronic phenotypes can be sustained by epigenetic mechanisms, including histone modifications such as deacetylation, we tested the hypothesis that histone deacetylation contributes to the maintenance of chronic anxiety and pain induced by prolonged exposure of the CeA to CORT. We found that bilateral infusions of a histone deacetylase inhibitor into the CeA attenuated anxiety-like behavior as well as somatic and visceral hypersensitivity resulting from elevated CORT exposure. Moreover, we delineated a novel pathway through which histone deacetylation could contribute to CORT regulation of GR and subsequent CRF expression in the CeA. Specifically, deacetylation of histone 3 at lysine 9 (H3K9), through the coordinated action of the NAD+-dependent protein deacetylase sirtuin-6 (SIRT6) and nuclear factor kappa B (NFκB), sequesters GR expression leading to disinhibition of CRF. Our results indicate that epigenetic programming in the amygdala, specifically histone modifications, is important in the maintenance of chronic anxiety and pain.

Predictors of anticipatory cortisol reactivity to subsequent stressors

Understanding the nature, predictors, and consequences of anticipatory biological stress responses are important in understanding long-term effects of repeated stressors. We examined anticipatory cortisol responses after an individual has actually experienced and reacted to a stressor once and is anticipating a second similar stressor. We hypothesized that how an individual reacts to the first stressor may predict that individual's anticipatory responses to further stressors. In Session 1, 77 male participants delivered speeches and performed arithmetic tasks in front of two evaluators. In Session 2 one week later, participants were told that they would do the same tasks again in front of evaluators. Stress cortisol reactivity in Session 1 (increase in cortisol from pre-stressor to post-stressor) predicted anticipatory cortisol reactivity in Session 2 (increase in cortisol from baseline to immediately pre-stressor). In addition, trait measures of low self-esteem and a "Submissive and Disconnected" interpersonal orientation predicted stronger anticipatory cortisol reactivity in Session 2. If the cortisol response to an initial stressor does in fact shape consequent anticipatory cortisol responses, this self-perpetuating nature of the initial cortisol response may contribute to negative long-term effects of repeated stressors on health. One factor that may be able to counteract this effect is a dominant and confident interpersonal orientation, which may lead to lower anticipatory cortisol reactions regardless of the response to the initial stressor.

Anticipatory sensitization to repeated stressors: the role of initial cortisol reactivity and meditation/emotion skills training

Anticipation may play a role in shaping biological reactions to repeated stressors-a common feature of modern life. We aimed to demonstrate that: (a) individuals who display a larger cortisol response to an initial stressor exhibit progressive anticipatory sensitization, showing progressively higher cortisol levels before subsequent exposures, and (b) attention/emotional skills training can reduce the magnitude of this effect on progressive anticipatory sensitization. Female school teachers (N=76) were randomly assigned to attention/emotion skills and meditation training or to a control group. Participants completed 3 separate Trier Social Stress Tests (TSST): at baseline (Session 1), post-training (Session 2), and five months post (Session 3). Each TSST session included preparing and delivering a speech and performing an arithmetic task in front of critical evaluators. In each session participants' salivary cortisol levels were determined before and after the stressor. Control participants with larger cortisol reactivity to the first stressor showed increasing anticipatory (pre-stressor) cortisol levels with each successive stressor exposure (TSST session)-suggesting progressive anticipatory sensitization. Yet this association was absent in the training group. Supplementary analyses indicated that these findings occurred in the absence of group differences in cortisol reactivity. Findings suggest that the stress response can undergo progressive anticipatory sensitization, which may be modulated by attention/emotion-related processes. An important implication of the construct of progressive anticipatory sensitization is a possible self-perpetuating effect of stress reactions, providing a candidate mechanism for the translation of short-to-long-term stress reactions.

Regional Gray Matter Volumes Are Related to Concern About Falling in Older People: A Voxel-Based Morphometric Study

BACKGROUND

Concern about falling is common in older people. Various related psychological constructs as well as poor balance and slow gait have been associated with decreased gray matter (GM) volume in old age. The current study investigates the association between concern about falling and voxel-wise GM volumes.

METHODS

A total of 281 community-dwelling older people aged 70-90 years underwent structural magnetic resonance imaging. Concern about falling was assessed using Falls Efficacy Scale-International (FES-I). For each participant, voxel-wise GM volumes were generated with voxel-based morphometry and regressed on raw FES-I scores (p < .05 family-wise error corrected on cluster level).

RESULTS

FES-I scores were negatively correlated with total brain volume (r = -.212; p ≤ .001), GM volume (r = -.210; p ≤ .001), and white matter volume (r = -.155; p ≤ .001). Voxel-based morphometry analysis revealed significant negative associations between FES-I and GM volumes of (i) left cerebellum and bilateral inferior occipital gyrus (voxels-in-cluster = 2,981; p < .001) and (ii) bilateral superior frontal gyrus and left supplementary motor area (voxels-in-cluster = 1,900; p = .004). Additional adjustment for vision and physical fall risk did not alter these associations. After adjustment for anxiety, only left cerebellum and bilateral inferior occipital gyrus remained negatively associated with FES-I scores (voxels-in-cluster = 2,426; p < .001). Adjustment for neuroticism removed all associations between FES-I and GM volumes.

CONCLUSIONS

Our study findings show that concern about falling is negatively associated with brain volumes in areas important for emotional control and for motor control, executive functions and visual processing in a large sample of older men and women. Regression analyses suggest that these relationships were primarily accounted for by psychological factors (generalized anxiety and neuroticism) and not by physical fall risk or vision.

Antagonism of corticotrophin-releasing factor type 1 receptors attenuates caloric intake of free feeding subordinate female rhesus monkeys in a rich dietary environment

Social subordination in macaque females is a known chronic stressor and previous studies have shown that socially subordinate female rhesus monkeys consume fewer kilocalories than dominant animals when a typical laboratory chow diet is available. However, in a rich dietary environment that provides access to chow in combination with a more palatable diet (i.e. high in fat and refined sugar), subordinate animals consume significantly more daily kilocalories than dominant conspecifics. Substantial literature is available supporting the role of stress hormone signals in shaping dietary preferences and promoting the consumption of palatable, energy-dense foods. The present study was conducted using stable groups of adult female rhesus monkeys to test the hypothesis that pharmacological treatment with a brain penetrable corticotrophin-releasing factor type 1 receptor (CRF1) antagonist would attenuate the stress-induced consumption of a palatable diet among subordinate animals in a rich dietary environment but would be without effect in dominant females. The results show that administration of the CRF1 receptor antagonist significantly reduced daily caloric intake of both available diets among subordinate females compared to dominant females. Importantly, multiple regression analyses showed that the attenuation in caloric intake in response to Antalarmin (Sigma-Aldrich, St Louis, MO, USA) was significantly predicted by the frequency of submissive and aggressive behaviour emitted by females, independent of social status. Taken together, the findings support the involvement of activation of CRF1 receptors in the stress-induced consumption of excess calories in a rich dietary environment and also support the growing literature concerning the importance of CRF for sustaining emotional feeding.

Effects of Music Listening on Pre-treatment Anxiety and Stress Levels in a Dental Hygiene Recall Population

BACKGROUND

Waiting for a medical procedure can exert significant feelings of state anxiety in patients. Music listening has been shown to be effective in decreasing anxiety levels. No study so far examined the potential anxiety and stress-reducing effect of a music intervention on pre-treatment anxiety and stress in patients waiting for dental hygiene treatment. Knowing whether the anxiety-reducing effect of music would also be detectible in the context of preventive routine medical procedures in healthy individuals would widen the area of application of music from the hospital or clinical environment to medical offices in general.

PURPOSE

Waiting for a medical treatment can induce anxiety and may lead to the experience of stress. We set out to examine the effect of music on pre-treatment anxiety in a healthy patient sample waiting for a dental treatment.

METHODS

In a randomized controlled clinical trial, 92 consecutive volunteer patients (mean age, 57 years) waiting for their scheduled dental hygiene treatment were randomly allocated to either an experimental (n = 46, listening to music for 10 min) or a control group (n = 46, waiting in silence). State and habitual anxiety, subjective stress, and mood measures were assessed before and after music listening or silence, respectively.

RESULTS

State anxiety levels in the music group decreased significantly after intervention as compared to the control group (F(1/90) = 8.06; p = 0.006). Participants' trait anxiety and dental anxiety were not found to moderate this effect.

CONCLUSIONS

Listening to music prior to dental hygiene treatment decreases anxiety levels to a greater extent than waiting in silence.

Allostatic load as a tool for monitoring physiological dysregulations and comorbidities in patients with severe mental illnesses

Severe mental illnesses like schizophrenia and bipolar disorder are disabling, chronic conditions that are often accompanied by medical comorbidities. In this theoretical article, we review the allostatic load model representing the "wear and tear" that chronic stress exacts on the brain and body. We propose an innovative way of monitoring physical and psychiatric comorbidities by integrating the allostatic load model into clinical practice. By interpreting peripheral biomarkers differently, medical professionals can calculate a simple, count-based, allostatic load index known to predict diverse stress-related pathologies. In addition to screening for comorbidities, allostatic load indices can be used to monitor the effects of pharmacological and psychosocial interventions. This framework can also be used to generate a dialogue between patient and practitioner to promote preventive and proactive approaches to health care.

Resilience and vulnerability: a neurobiological perspective

The brain is constantly adapting to a changing environment. It detects environmental stimuli, integrates that information with internal states, and engages appropriate behavioral and physiological responses. This process of stability through change is termed “allostasis”, and serves as a mechanism by which an organism can adapt to a changing environment to function optimally, and ultimately ensure survival. The ability to adapt to stressors in the environment by “bending” but not “breaking” can be considered as “resilience”. Individuals that are more able to withstand such challenges to their stability, and bounce back after, can be considered more resilient than those that do not. This review will explore what resilience means in a neurobiological context, the role of stress and allostasis, and focuses on the role of neurotrophins, particularly BDNF, in mediating adaptive plasticity.

Early and prolonged exposure to reward delay: effects on impulsive choice and alcohol self-administration in male rats

Naturally occurring impulsive choice has been found to positively predict alcohol consumption in rats. However, the extent to which experimental manipulation of impulsive choice may modify alcohol consumption remains unclear. In the present study, we sought to: (a) train low levels of impulsive choice in rats using early, prolonged exposure to reward delay, and (b) determine the effects of this manipulation on subsequent alcohol consumption. During a prolonged training regimen, three groups of male, adolescent Long-Evans rats (21-22 days old at intake) responded on a single lever for food rewards delivered after either a progressively increasing delay, a fixed delay, or no delay. Posttests of impulsive choice were conducted, as was an evaluation of alcohol consumption using a limited-access, two-bottle test. Following delay-exposure training, both groups of delay-exposed rats made significantly fewer impulsive choices than did rats in the no-delay group. In addition, fixed-delay rats consumed significantly more alcohol during daily, 30-min sessions than no-delay rats. Possible mechanisms of these effects are discussed, as is the significance of these findings to nonhuman models of addiction.

Annual Research Review: The neurobiology and physiology of resilience and adaptation across the life course

BACKGROUND

Adaptation is key to survival. An organism must adapt to environmental challenges in order to be able to thrive in the environment in which they find themselves. Resilience can be thought of as a measure of the ability of an organism to adapt, and to withstand challenges to its stability. In higher animals, the brain is a key player in this process of adaptation and resilience, and through a process known as "allostasis" can obtain "stability through change"; protecting homeostasis in the face of stressors in the environment. Mediators of allostasis, such as glucocorticoids, can cause changes in the structure and function of neural circuits, clearly impacting behavior. How developmental stage interacts with stress and leads to long-lasting changes is a key question addressed in this review.

SCOPE AND METHODS

We discuss the concept of allostasis, its role in resilience, the neural and physiological systems mediating these responses, the modulatory role of development, and the consequences for adult functioning. We present this in the context of mediators the brain and body engage to protect against threats to homeostasis. The review has been informed by comprehensive searches on PubMed and Scopus through November 2012.

FINDINGS

Stressors in the environment can have long lasting effects on development, depending upon the stage of life at which they are experienced. As such, adverse childhood experiences can alter resilience of individuals, making it more difficult for them to respond normally to adverse situations in adulthood, but the brain maintains the capacity to re-enter a more plastic state where such effects can be mitigated.

CONCLUSIONS

The brain regulates responses that allow for adaptation to challenges in the environment. The capacity of the brain and body to withstand challenges to stability can be considered as "resilience". While adverse childhood experiences can have long-term negative consequences, under the right circumstances, the brain can re-enter plastic states, and negative outcomes may be mitigated, even later in life.

Physiological Regulation at 9 Months of Age in Infants Prenatally Exposed to Cigarettes

The primary purpose of this study was to examine the association between prenatal cigarette exposure and physiological regulation at 9 months of age. Specifically, we explored the possibility that any association between prenatal cigarette exposure and infant physiological regulation was moderated by postnatal environmental tobacco smoke (ETS) exposure or infant gender. We evaluated whether male infants with prenatal cigarette exposure or infants who were also exposed to ETS after birth had the highest levels of physiological dysregulation. Respiratory sinus arrhythmia (RSA) was obtained from 206 (142 exposed and 64 nonexposed) infants during a baseline period and during procedures designed to elicit both positive and negative affect. There was a significant suppression of RSA during the negative affect task for nonexposed infants but not for exposed infants. Postnatal ETS exposure did not moderate this association; however, gender did moderate this association such that boys with prenatal cigarette exposure had a significant increase in RSA rather than the suppression seen among both nonexposed boys and girls. These results provide additional support for the idea that boys are particularly vulnerable to the effects of prenatal cigarette exposure.