Relations between mechanisms of CNS arousal and mechanisms of stress

In the centennial year of the birth of Hans Selye, this review compares his classical concepts of stress with a modern approach to mechanisms of CNS arousal. Relations between the two concepts are described. Neuroanatomical, neurophysiological, and functional genomic mechanisms underlying CNS arousal are briefly reviewed. Controls over stress responses and arousal are compared to particular concepts of control system engineering. Understanding these two systems is of crucial importance because their dysregulation is associated with large numbers of disease states.     

Core mechanisms in "theory of mind"

Our ability to understand the thoughts and feelings of other people does not initially develop as a theory but as a mechanism. The "theory of mind" mechanism (ToMM) is part of the core architecture of the human brain, and is specialized for learning about mental states. Impaired development of this mechanism can have drastic effects on social learning, seen most strikingly in the autistic spectrum disorders. ToMM kick-starts belief-desire attribution but effective reasoning about belief contents depends on a process of selection by inhibition. This selection process (SP) develops slowly through the preschool period and well beyond. By modeling the ToMM-SP as mechanisms of selective attention, we have uncovered new empirical phenomena. We propose that early "theory of mind" is a modular-heuristic process of domain-specific learning.     

The tell-tale heart: physiological reactivity during resolution of ambiguity in youth anxiety

In the past decade, cognitive biases and physiological arousal have each been proposed as mechanisms through which paediatric anxiety develops and is maintained over time. Preliminary studies have found associations between anxious interpretations of ambiguity, physiological arousal, and avoidance, supporting theories that link cognition, psychophysiology, and behaviour. However, little is known about the relationship between youths’ resolutions of ambiguity and physiological arousal during acute stress. Such information may have important clinical implications for use of verbal self-regulation strategies and cognitive restructuring during treatments for paediatric anxiety. In this brief report, we present findings suggesting that anxious, but not typically developing, youth select avoidant goals via non-threatening resolution of ambiguity during a stressor, and that this resolution of ambiguity is accompanied by physiological reactivity (heart rate, heart rate variability, and respiratory sinus arrhythmia). We propose future empirical research on the interplay between interpretation bias, psychophysiology, and child anxiety, as well as clinical implications.     

Depression and stress: a biopsychosocial exploration of evolved functions and mechanisms

Depression is a common and debilitating disorder linked to social adversity and stress. There have been many theories suggesting possible evolved functions of depression but few have explored evolved defensive mechanisms for coping with stressful events and how these maybe compromised in human depression. This paper will review some of the current evolutionary theories of depression and explore how major depression can arise when evolved defences to cope with adversity (e.g., fight, flight, disengage, submit and help-seeking) are aroused but blocked, arrested or ineffective. Psychosocial stressors can be seen as both activating,but also as arresting, evolved stress-coping defences leading to chronic states of stress with physiological effects on mood. This paper is set in the context of an evolution informed biopsychosocial approach.     

Mind over matter: reappraising arousal improves cardiovascular and cognitive responses to stress

Researchers have theorized that changing the way we think about our bodily responses can improve our physiological and cognitive reactions to stressful events. However, the underlying processes through which mental states improve downstream outcomes are not well understood. To this end, we examined whether reappraising stress-induced arousal could improve cardiovascular outcomes and decrease attentional bias for emotionally negative information. Participants were randomly assigned to either a reappraisal condition in which they were instructed to think about their physiological arousal during a stressful task as functional and adaptive, or to 1 of 2 control conditions: attention reorientation and no instructions. Relative to controls, participants instructed to reappraise their arousal exhibited more adaptive cardiovascular stress responses-increased cardiac efficiency and lower vascular resistance-and decreased attentional bias. Thus, reappraising arousal shows physiological and cognitive benefits. Implications for health and potential clinical applications are discussed.     

Neural synchronization as a hypothetical explanation of the psychoanalytic unconscious

Cognitive scientists have tried to explain the neural mechanisms of unconscious mental states such as coma, epileptic seizures, and anesthesia-induced unconsciousness. However these types of unconscious states are different from the psychoanalytic unconscious. In this review, we aim to present our hypothesis about the neural correlates underlying psychoanalytic unconscious. To fulfill this aim, we firstly review the previous explanations about the neural correlates of conscious and unconscious mental states, such as brain oscillations, synchronicity of neural networks, and cognitive binding. By doing so, we hope to lay a neuroscientific ground for our hypothesis about neural correlates of psychoanalytic unconscious; parallel but unsynchronized neural networks between different layers of consciousness and unconsciousness. Next, we propose a neuroscientific mechanism about how the repressed mental events reach the conscious awareness; the lock of neural synchronization between two mental layers of conscious and unconscious. At the last section, we will discuss the data about schizophrenia as a clinical example of our proposed hypothesis.     

The default mode network and altered consciousness in epilepsy

The default mode network has been hypothesized based on the observation that specific regions of the brain are consistently activated during the resting state and deactivated during engagement with task. The primary nodes of this network, which typically include the precuneus/posterior cingulate, the medial frontal and lateral parietal cortices, are thought to be involved in introspective and social cognitive functions. Interestingly, this same network has been shown to be selectively impaired during epileptic seizures associated with loss of consciousness. Using a wide range of neuroimaging and electrophysiological modalities, decreased activity in the default mode network has been confirmed during complex partial, generalized tonic-clonic, and absence seizures. In this review we will discuss these three seizure types and will focus on possible mechanisms by which decreased default mode network activity occurs. Although the specific mechanisms of onset and propagation differ considerably across these seizure types, we propose that the resulting loss of consciousness in all three types of seizures is due to active inhibition of subcortical arousal systems that normally maintain default mode network activity in the awake state. Further, we suggest that these findings support a general "network inhibition hypothesis", by which active inhibition of arousal systems by seizures in certain cortical regions leads to cortical deactivation in other cortical areas. This may represent a push-pull mechanism similar to that seen operating between cortical networks under normal conditions.     

Psychological defense mechanisms and electroencephalographic arousal

The aim of this study was to examine the relationship between psychological defense as measured by the Kragh tachistoscopic Defense Mechanisms Test (DMT), and general arousal properties of the individual as measured with electroencephalogram (EEG). The DMT assesses defense by presenting neutral and threatening pictures with very short exposure times. EEG characteristics were measured in the 8–12 Hz EEG frequency band during DMT testing. Twenty-one male subjects participated in the study. All were US Air Force personnel on active duty. Personnel with high defense mechanisms, defined in this connection as slow perception of the threat, tended to have higher cortical arousal after Stimulus exposure than the subjects with low defense mechanisms. The differences occurred mainly with new stimulus material without any threatening content. The differences in arousal response to novel stimuli may contribute to an understanding of the relationships between the Kragh DMT test and performance in life-threatening situations.     

Psychological mechanisms in the maintenance of insomnia: arousal, distress, and sleep-related beliefs

The purpose of this study was to examine whether arousal, distress, and sleep-related beliefs are related to the maintenance of insomnia. From a randomly selected sample from the general population (n=3600), 1936 participants filled out a baseline and 1-year follow-up survey. Logistic regressions were used to investigate whether arousal, distress, and beliefs were related to sleep status (insomnia: n=116; poor sleep: n=222; normal sleep: n=529; good sleep: n=234) over 1 year. Cluster analysis was employed to assess whether it was possible to classify the participants based on their profiles of psychological functioning. The results showed that beliefs in the long-term negative consequences of insomnia, anxiety, depression, and arousal were significantly related to the maintenance of insomnia (18-72% of the variance). Of the individuals with persistent insomnia, 91% belonged to a cluster characterized by high scores on sleep-related beliefs, anxiety, depression, and arousal, and 9% to a cluster defined by low scores on the mechanisms. This study shows that sleep-related beliefs, anxiety, depression, and arousal are related to the maintenance of persistent insomnia, but also that these mechanisms often co-occur in individuals with insomnia.     

急性应激影响工作记忆的生理心理机制

急性应激是机体面对外界环境变化所产生的一系列生理和心理反应, 对认知加工, 尤其是核心的工作记忆能力产生深远影响, 然而以往的研究存在大量不一致的结果。从应激诱发方式、工作记忆加工子成分、个体差异等三个方面系统阐释应激影响工作记忆的生理心理机制, 并结合认知神经机制的框架, 可以更好地理解以往的结果。未来研究应综合考虑应激诱发、认知任务和响应个体等方面的差异对应激带来的影响, 并关注急性应激负面影响的干预与调控。     

Emotional processes in risky and multiattribute health decisions

Objective: Here, we develop an integrative account of the roles of emotion in decision-making. In Part I, we illustrate how emotional inputs into decisions may rely on physiological signals from emotions experienced while making the decision, and we review evidence suggesting that the failure to represent the emotional meaning of options can often reduce decision quality. We propose that health-related decrements in the ability to generate emotional reactions lead people to inaccurately represent emotional responses and compromise decisions, particularly about risk. Part II explores complex decisions in which choice options involve trade-offs between positive and negative attributes. We first review evidence showing that difficult trade-off decisions generate negative affect and physiological arousal. Next, we propose that medical decision-making will be linked to short- and long-term stress and health outcomes.

Conclusion: In sum, this article proposes and reviews initial evidence supporting the effective use and management of emotional inputs as important to both clinical and non-clinical populations. Our approach will contribute to the understanding of patient-centred emotional decision-making and will inform medical decision aids.     

Memory mechanisms supporting syntactic comprehension

Efforts to characterize the memory system that supports sentence comprehension have historically drawn extensively on short-term memory as a source of mechanisms that might apply to sentences. The focus of these efforts has changed significantly in the past decade. As a result of changes in models of short-term working memory (ST-WM) and developments in models of sentence comprehension, the effort to relate entire components of an ST-WM system, such as those in the model developed by Baddeley (Nature Reviews Neuroscience 4: 829–839, 2003) to sentence comprehension has largely been replaced by an effort to relate more specific mechanisms found in modern models of ST-WM to memory processes that support one aspect of sentence comprehension—the assignment of syntactic structure (parsing) and its use in determining sentence meaning (interpretation) during sentence comprehension. In this article, we present the historical background to recent studies of the memory mechanisms that support parsing and interpretation and review recent research into this relation. We argue that the results of this research do not converge on a set of mechanisms derived from ST-WM that apply to parsing and interpretation. We argue that the memory mechanisms supporting parsing and interpretation have features that characterize another memory system that has been postulated to account for skilled performance—long-term working memory. We propose a model of the relation of different aspects of parsing and interpretation to ST-WM and long-term working memory.     

Reasoning and concurrent timing: a study of the mechanisms underlying the effect of emotion on reasoning

Negative emotions typically have an adverse effect on reasoning, especially analytic or logical reasoning. This effect can be explained using an attentional framework in which emotion detracts limited-capacity cognitive resources which are required for reasoning. Another possibility is that the effect of emotion on reasoning is mediated by arousal, as previous research has shown that physiological arousal can be associated with decreased reasoning performance. In this research, we used a dual-task paradigm combining a syllogistic reasoning task and a time production task. Prospective timing allows to disentangle the effects of attention and arousal: time productions should lengthen if emotion takes up cognitive resources that are therefore not available for timing, whereas time productions should shorten if emotional reasoning results from increased arousal. Results from two experiments confirm the adverse impact of emotion on logical reasoning performance. Reasoning about emotional contents led to lengthened time productions, which suggests that the capture of limited cognitive resources is the main factor accounting for the adverse effect of emotion on reasoning and not arousal.     

Rehabilitation of brain damage: brain plasticity and principles of guided recovery.

Rehabilitation of the damaged brain can foster reconnection of damaged neural circuits; Hebbian learning mechanisms play an important part in this. The authors propose a triage of post-lesion states, depending on the loss of connectivity in particular circuits. A small loss of connectivity will tend to lead to autonomous recovery, whereas a major loss of connectivity will lead to permanent loss of function; for such individuals, a compensatory approach to recovery is required. The third group have potentially rescuable lesioned circuits, but guided recovery depends on providing precisely targeted bottom-up and top-down inputs, maintaining adequate levels of arousal, and avoiding activation of competitor circuits that may suppress activity in target circuits. Empirical data are implemented in a neural network model, and clinical recommendations for the practice of rehabilitation following brain damage are made.     

Improving sleep with mindfulness and acceptance: A metacognitive model of insomnia

While there is an accumulating evidence to suggest that therapies using mindfulness and acceptance-based approaches have benefits for improving the symptoms of insomnia, it is unclear how these treatments work. The goal of this paper is to present a conceptual framework for the cognitive mechanisms of insomnia based upon mindfulness and acceptance approaches. The existing cognitive and behavioral models of insomnia are first reviewed and a two-level model of cognitive (primary) and metacognitive (secondary) arousal is presented in the context of insomnia. We then focus on the role of metacognition in mindfulness and acceptance-based therapies, followed by a review of these therapies in the treatment of insomnia. A conceptual framework is presented detailing the mechanisms of metacognition in the context of insomnia treatments. This model proposes that increasing awareness of the mental and physical states that are present when experiencing insomnia symptoms and then learning how to shift mental processes can promote an adaptive stance to one's response to these symptoms. These metacognitive processes are characterized by balanced appraisals, cognitive flexibility, equanimity, and commitment to values and are posited to reduce sleep-related arousal, leading to remission from insomnia. We hope that this model will further the understanding and impact of mindfulness and acceptance-based approaches to insomnia.     

Arousal and the Relationship Between Positive and Negative Affect: An Analysis of the Data of Ito,Cacioppo, and Lang (1998)

Research on positive and negative emotional states has supported several models of how those states relate to each other. Many studies suggest that they are independent, the bivariate view, while others suggest that they are inversely correlated, the bipolar view. Other research has shown that stress is a major moderator of the relationship; the affects become coupled under conditions of high stress, a contextual model, but are relatively independent otherwise. To expand the range of tests of this dynamic model of affect, we reanalyzed a data set initially reported by Ito, Cacioppo, and Lang (1998) on affect-eliciting picture stimuli. In that study, arousal was assessed separately from positive and negative affect, allowing investigation of a source of interaffect relationships different from stress, per se. Arousal interacted with positive and negative affect, showing both bivariate and bipolar relationships, and effects similar to stress. Affective reactions to the stimuli became more inversely correlated when the affects were high and interacting with higher arousal. The data supported the dynamic model of affect and suggest the need for further analyses of the linkages between stress, arousal, and reduced levels of emotional complexity.     

The Biological Findings in Post-Traumatic Stress Disorder: A Review1

In this paper the authors review the literature on biological and treatment studies of post-traumatic stress disorder (PTSD) and present current unifying hypotheses regarding the pathophysiology. The psychophysiological studies stress overarousal, while endocrine studies suggest a decreased Cortisol production in denial and low symptom states with increases in highly symptomatic states. Suggestive evidence is provided that PTSD is associated with permanent changes in brain mechanisms involving the locus coeruleus, amygdala, and the hypothalamo-pituitary-adrenal axis. Drug treatments are promising but not fully satisfactory as yet. Directions for further research are provided.     

Modulation of anxiety circuits by serotonergic systems

Anxiety is a complex emotional state associated with sustained heightened autonomic and behavioral arousal and an increase in avoidance behavior. Anxiety-related behavior is a form of risk assessment behavior that is associated with a level of uncertainty or unpredictability regarding the outcome of emotionally salient events, often when both rewarding and aversive outcomes are possible. In this review, we highlight recent advances in our understanding of the neural circuits regulating anxiety states and anxiety-related behavior with an emphasis on the role of brainstem serotonergic systems in modulating anxiety-related circuits. In particular, we explore the possibility that the regulation of anxiety states and anxiety-related behavior by serotonergic systems is dependent on a specific, topographically organized mesolimbocortical serotonergic system that originates in the mid-rostrocaudal and caudal parts of the dorsal raphe nucleus.     

Neural mechanisms underlying subsequent memory for personal beliefs:An fMRI study

Many fMRI studies have examined the neural mechanisms supporting emotional memory for stimuli that generate emotion rather automatically (e.g., a picture of a dangerous animal or of appetizing food). However, far fewer studies have examined how memory is influenced by emotion related to social and political issues (e.g., a proposal for large changes in taxation policy), which clearly vary across individuals. In order to investigate the neural substrates of affective and mnemonic processes associated with personal opinions, we employed an fMRI task wherein participants rated the intensity of agreement/disagreement to sociopolitical belief statements paired with neural face pictures. Following the rating phase, participants performed an associative recognition test in which they distinguished identical versus recombined face–statement pairs. The study yielded three main findings: behaviorally, the intensity of agreement ratings was linked to greater subjective emotional arousal as well as enhanced high-confidence subsequent memory. Neurally, statements that elicited strong (vs. weak) agreement or disagreement were associated with greater activation of the amygdala. Finally, a subsequent memory analysis showed that the behavioral memory advantage for statements generating stronger ratings was dependent on the medial prefrontal cortex (mPFC). Together, these results both underscore consistencies in neural systems supporting emotional arousal and suggest a modulation of arousal-related encoding mechanisms when emotion is contingent on referencing personal beliefs.     

The Influence of Work-Induced Psychological States on Behavior at Home

This article explores the processes by which employees' emotional states at the end of their work day are reflected in subsequent behavior at home. Previous research in this area is critiqued in terms of measurement issues and research design, and data are used to illustrate ways in which this phenomenon could be more accurately examined. This study links reports of four psychological states (stress, fatigue, arousal, and depression), collected from 29 men on 2 weekdays following their return home from work, to subsequent involvement in household tasks, leisure, and negative marital interactions. Group comparisons, comparing men "high" and "low" on the various states, produced a generally consistent pattern, although results were usually not statistically significant on both occasions of measurement. When nonparametric prediction analysis was utilized, however, a cleaner pattern emerged with: (a) high levels of stress and fatigue associated with low involvement in housework, (b) low levels of stress and high levels of arousal associated with greater involvement in active leisure, and (c) higher stress associated with higher levels of negative marital interactions. The data collecting method used in this study is evaluated, the strengths and weaknesses of the methodology are identified, and implications for future research are considered.