Deactivation of the limbic system during acute psychosocial stress: evidence from positron emission tomography and functional magnetic resonance imaging studies

Limbic and cortical control of phonation for speech in response to a public speech preparation stressor

Knowledge on brain networks subserving vocalization in vocally healthy individuals under various task conditions is scarce but paramount to understand voice disorders. The aims of our study were to determine (1) the effect of social-evaluative stress on the central neural control of phonation underlying speech production; and (2) the neural signature, personality profile, and aerodynamic vocal function in relation to salivary cortisol responses. Thirteen vocally healthy females underwent an event-related sparse-sampling fMRI protocol consisting of voiced and whispered sentence productions with and without exposure to the social-evaluative stressor public speaking anticipation. Participants completed a personality questionnaire, rating scales of negative emotional state, and provided salivary cortisol samples. In the total sample, the task contrast of voiced productions revealed that stressor exposure resulted in a peak activation in the right caudate with concomitant deactivations in the bilateral pgACC and aMCC, and right IFG, BA 9, BA 10, insula, putamen, and thalamus. There were individual differences in stressor-induced brain activations as a function of stress reactivity with greater cortisol reactivity linked with lower laryngeal motor cortex activity and lower scores on aspects of extraversion. Our data confirm that stress alters the phonatory control for speech production through limbic-motor interactions. The findings support the Trait Theory of Voice Disorders (Roy and Bless 2000) and help provide critical insights to the study of voice disorders such as primary muscle tension dysphonia.

Distinct Effects of Social Stress on Working Memory in Obsessive-Compulsive Disorder

Stress might exaggerate the compulsion and impair the working memory of patients with obsessive-compulsive disorder (OCD). This study evaluated the effect of stress on the cognitive neural processing of working memory in OCD and its clinical significance using a "number calculation working memory" task. Thirty-eight patients and 55 gender- and education-matched healthy controls were examined. Stress impaired the performance of the manipulation task in patients. Healthy controls showed less engagement of the medial prefrontal cortex and striatum during the task under stress versus less stress, which was absent in the patients with OCD. The diagnosis × stress interaction effect was significant in the right fusiform, supplementary motor area, precentral cortex and caudate. The failure of suppression of the medial prefrontal cortex and striatum and stress-related hyperactivation in the right fusiform, supplementary motor area, precentral cortex, and caudate might be an OCD-related psychopathological and neural response to stress.

Associations between brain activity and endogenous and exogenous cortisol - A systematic review

To arrive at a coherent understanding of the relation between glucocorticoids and the human brain, we systematically reviewed the literature for studies examining the associations between endogenous or exogenous cortisol and human brain function. Higher levels of endogenous cortisol during psychological stress were related to increased activity in the middle temporal gyrus and perigenual anterior cingulate cortex (ACC), decreased activity in the ventromedial prefrontal cortex, and altered function (i.e., mixed findings, increased or decreased) in the amygdala, hippocampus and inferior frontal gyrus. Moreover, endogenous cortisol response to psychological stress was related to increased activity in the inferior temporal gyrus and altered function in the amygdala during emotional tasks that followed psychological stress. Exogenous cortisol administration was related to increased activity in the postcentral gyrus, superior frontal gyrus and ACC, and altered function in the amygdala and hippocampus during conditioning, emotional and reward-processing tasks after cortisol administration. These findings were in line with those from animal studies on amygdala activity during and after stress.

Stress Impairs Intentional Memory Control through Altered Theta Oscillations in Lateral Parietal Cortex

Accumulating evidence suggests that forgetting is not necessarily a passive process but that we can, to some extent, actively control what we remember and what we forget. Although this intentional control of memory has potentially far-reaching implications, the factors that influence our capacity to intentionally control our memory are largely unknown. Here, we tested whether acute stress may disrupt the intentional control of memory and, if so, through which neural mechanism. We exposed healthy men and women to a stress (n = 27) or control (n = 26) procedure before they aimed repeatedly to retrieve some previously learned cue-target pairs and to actively suppress others. While control participants showed reduced memory for suppressed compared with baseline pairs in a subsequent memory test, this suppression-induced forgetting was completely abolished after stress. Using magnetoencephalography (MEG), we show that the reduced ability to suppress memories after stress is associated with altered theta activity in the inferior temporal cortex when the control process (retrieval or suppression) is triggered and in the lateral parietal cortex when control is exerted, with the latter being directly correlated with the stress hormone cortisol. Moreover, the suppression-induced forgetting was linked to altered connectivity between the hippocampus and right dorsolateral prefrontal cortex (PFC), which in turn was negatively correlated to stress-induced cortisol increases. These findings provide novel insights into conditions under which our capacity to actively control our memory breaks down and may have considerable implications for stress-related psychopathologies, such as posttraumatic stress disorder (PTSD), that are characterized by unwanted memories of distressing events.SIGNIFICANCE STATEMENT It is typically assumed that forgetting is a passive process that can hardly be controlled. There is, however, evidence that we may actively control, to some extent, what we remember and what we forget. This intentional memory control has considerable implications for mental disorders in which patients suffer from unwanted (e.g., traumatic) memories. Here, we demonstrate that the capacity to intentionally control our memory breaks down after stress. Using magnetoencephalography (MEG), we show that this stress-induced memory control deficit is linked to altered activity in the lateral parietal cortex and the connectivity between the hippocampus and right prefrontal cortex (PFC). These findings provide novel insights into conditions under which memory control fails and are highly relevant in the context of stress-related psychopathologies.

Individual differences in accumbofrontal tract integrity relate to risky decisions under stress in adolescents and adults

Psychosocial stress increases risky decision-making (DM). It is widely accepted that individual variation in neural phenotypes underlie variability in this behavioral tendency in adults, but is less examined in adolescents. Our goal was to test the hypothesis that the relation between neural phenotypes and stress-related risky DM is better characterized by individual variation than by age. Using diffusion tensor imaging (DTI) tractography to characterize the accumbofrontal tract, we determined if it uniquely moderated how stress affects risky DM, over and above age. A daily diary design monitored participants’ daily stress for two weeks. Participants completed a DTI scan and performed a task in which decisions varied by expected value, once each on a day when they endorsed feeling higher (and lower) than usual levels of stress. Multilevel logistic regression analyses revealed that all participants were more likely to take risks as expected reward value increased; this behavior was greater under high versus low stress for individuals with low accumbofrontal tract integrity, whereas DM was less influenced by stress for individuals with high accumbofrontal tract integrity, regardless of age. Results suggest that individual differences in brain structure may be more germane to characterizing risky decisions in adolescents, rather than ontogeny.

Healthy women with severe early life trauma show altered neural facilitation of emotion inhibition under acute stress

BACKGROUND

Across psychopathologies, trauma-exposed individuals suffer from difficulties in inhibiting emotions and regulating attention. In trauma-exposed individuals without psychopathology, only subtle alterations of neural activity involved in regulating emotions have been reported. It remains unclear how these neural systems react to demanding environments, when acute (non-traumatic but ordinary) stress serves to perturbate the system. Moreover, associations with subthreshold clinical symptoms are poorly understood.

METHODS

The present fMRI study investigated response inhibition of emotional faces before and after psychosocial stress situations. Specifically, it compared 25 women (mean age 31.5 ± 9.7 years) who had suffered severe early life trauma but who did not have a history of or current psychiatric disorder, with 25 age- and education-matched trauma-naïve women.

RESULTS

Under stress, response inhibition related to fearful faces was reduced in both groups. Compared to controls, trauma-exposed women showed decreased left inferior frontal gyrus (IFG) activation under stress when inhibiting responses to fearful faces, while activation of the right anterior insula was slightly increased. Also, groups differed in brain-behaviour correlations. Whereas stress-induced false alarm rates on fearful stimuli negatively correlated with stress-induced IFG signal in controls, in trauma-exposed participants, they positively correlated with stress-induced insula activation.

CONCLUSION

Neural facilitation of emotion inhibition during stress appears to be altered in trauma-exposed women, even without a history of or current psychopathology. Decreased activation of the IFG in concert with heightened bottom-up salience of fear related cues may increase vulnerability to stress-related diseases.

Endogenous cortisol-related alterations of right anterior insula functional connectivity under acute stress

BACKGROUND

Previous studies have suggested that the right anterior insula (rAI) plays a vital role in salience processing and stress-related disorders. In this study, we aimed to investigate the relationship between rAI functional connectivity changes and individual differences in cortisol responses after acute stress, in order to provide insights into psychiatric illness vulnerabilities.

METHODS

Thirty-five young men were enrolled in a randomized, counterbalanced two-session study, with aversive movie clip combined with electrical shocks as stress stimulation and the neutral movie clip as control stimulation. Resting-state fMRI data was acquired after movie exposure. The rAI was chosen as seed for functional connectivity analysis. We then examined the effect of acute stress on rAI functional connectivity and its association with individuals' cortisol response.

RESULTS

We found decreased rAI functional connectivity in the fronto-parietal regions, but increased functional connectivity in the visual and somatosensory areas following acute stress. Moreover, stress-induced cortisol response was significantly positively correlated with the rAI functional connectivity in the medial prefrontal cortex, and negatively correlated with the orbital-frontal cortex, lingual gyrus, and middle temporal gyrus.

LIMITATIONS

Only young Chinese males without any trauma experience were recruited in this study.

CONCLUSIONS

The results suggested tight link between specific rAI functional connectivity alterations and individual stress reactivity, which may help elucidate the potential neurobiological mechanism underlying vulnerability to stress-related disorders.

Stress Changes the Resting-State Cortical Flow of Information from Distributed to Frontally Directed Patterns

Despite converging evidence on the involvement of large-scale distributed brain networks in response to stress, the effect of stress on the components of these networks is less clear. Although some studies identify higher regional activities in response to stress, others observe an opposite effect in the similar regions. Studies based on synchronized activities and coactivation of these components also yield similar differing results. However, these differences are not necessarily contradictory once we observe the effect of stress on these functional networks in terms of the change in information processing capacity of their components. In the present study, we investigate the utility of such a shift in the analysis of the effect of stress on distributed cortical regions through quantification of the flow of information among them. For this purpose, we use the self-assessed responses of 216 individuals to stress-related questionnaires and systematically select 20 of them whose responses showed significantly higher and lower susceptibility to stress. We then use these 20 individuals' resting-state multi-channel electroencephalography (EEG) recordings (both Eyes-Closed (EC) and Eyes-Open (EO) settings) and compute the distributed flow of information among their cortical regions using transfer entropy (TE). The contribution of the present study is three-fold. First, it identifies that the stress-susceptibility is characterized by the change in flow of information in fronto-parietal brain network. Second, it shows that these regions are distributed bi-hemispherically and are sufficient to significantly differentiate between the individuals with high versus low stress-susceptibility. Third, it verifies that the high stress-susceptibility is markedly associated with a higher parietal-to-frontal flow of information. These results provide further evidence for the viewpoint in which the brain's modulation of information is not necessarily accompanied by the change in its regional activity. They further construe the effect of stress in terms of a disturbance that disrupts the flow of information among the brain's distributed cortical regions. These observations, in turn, suggest that some of the differences in the previous findings perhaps reflect different aspects of impaired distributed brain information processing in response to stress. From a broader perspective, these results posit the use of TE as a potential diagnostic/prognostic tool in identification of the effect of stress on distributed brain networks that are involved in stress-response.

Sex-linked neurofunctional basis of psychological resilience in late adolescence: a resting-state functional magnetic resonance imaging study

Psychological resilience refers to the ability to adapt effectively in the face of adversity, which is closely related to an individual's psychological and physical health and well-being. Although previous behavioural studies have shown sex differences in psychological resilience, little is known about the neural basis of sex differences in psychological resilience. Here, we measured amplitude of low-frequency fluctuations (ALFF) via resting-state functional magnetic resonance imaging to investigate the sex-linked neurofunctional basis of psychological resilience in 231 healthy adolescents. At the behavioural level, we replicated previous findings indicating that males are more resilient than females. At the neural level, we found sex differences in the relationship between psychological resilience and ALFF in the right orbitofrontal cortex (OFC). Specifically, males showed a positive correlation between psychological resilience and ALFF in the right OFC, while females showed a negative correlation in this region. The sex-specific association between psychological resilience and spontaneous brain activity might be dependent on differences in hormonal systems and brain development between male and female adolescents. Taken together, the results of our study might provide the first evidence of sex-specific neurofunctional substrates of psychological resilience in adolescents, emphasizing the vital role of sex effects in future psychological resilience-related studies.

The functional networks of a novel environment: Neural activity mapping in awake unrestrained rats using positron emission tomography

INTRODUCTION

Novel environment stimulation is thought to have an important role in cognitive development and has been shown to encourage exploratory behavior in rats. However, psychopathology or perceived danger or stress can impede this exploratory drive. The balance between brain circuits controlling the exploratory drive elicited by a novel environment, and the avoidance response to stressors, is not well understood.

METHODS

Using positron emission tomography (PET) and the glucose analog [¹⁸ F]fluorodeoxyglucose (18F-FDG), we assessed awake brain glucose metabolism (BGluM) in rats while in a novel environment (cage of an unfamiliar male rat) and non-novel environment (the animal's home cage).

RESULTS

Exposure to the novel environment increased BGluM in regions associated with vision (visual cortex), motor function and motivated behavior (striatum and motor cortex), and anxiety (stria terminalis), and decreased BGluM in regions associated with auditory processing (auditory cortex, insular cortex, inferior colliculus), locomotor activity (globus pallidus, striatum, motor cortex, ventral thalamic nucleus), spatial navigation (retrosplenial cortex), and working memory (hippocampus, cingulate cortex, prelimbic cortex, orbitofrontal cortex).

CONCLUSION

These results suggest that the novel cage is a stressful environment that inhibits activity in brain regions associated with exploratory behavior. Patterns of inhibition in the novel cage also support the proposed rat default mode network, indicating that animals are more cognitively engaged in this environment. Additionally, these data support the unique capability of combining FDG-PET with psychopharmacology experiments to examine novelty seeking and brain activation in the context of decision making, risk taking, and cognitive function more generally, along with response to environmental or stress challenges.

Cortisol secretion predicts functional macro-scale connectivity of the visual cortex: A data-driven Multivoxel Pattern Analysis (MVPA)

BACKGROUND

Functional connectivity is a fundamental principle of brain organization. Cortisol, the end product of the hypothalamic-pituitary-adrenal axis, is a potent modulator of brain functions. Previous studies investigating the association between cortisol levels on brain connectivity are, however, limited to specifica priori defined brain networks. Such hypothesis-driven approaches only partly capture the full extent of spatial modulatory effects that cortisol exerts on brain connectivity. Consequently, the aim of this study was a data-driven identification of brain regions where connectivity patterns covary significantly with cortisol levels.

METHODS

Eighty-eight healthy right-handed individuals participated in a task-independent fMRI-resting-state functional connectivity (rsFC) measurement. The cortisol concentrations in saliva were measured at eight points in time around the resting state measurement. Using a multi-voxel pattern analysis (MVPA), seed regions were identified whose activity covaried strongest with cortisol levels. Seed-to-voxel analyses were then performed to isolate corresponding networks affected by cortisol variation.

RESULTS

The MVPA identified three regions in the primary and secondary visual cortex where connectivity patterns were associated with cortisol secretion. Seed-to-voxel analysis revealed large lateral connectivity clusters that mainly correspond to the salience and control network, but also to auditory and pericentral regions. Subsequent dose-response analysis suggests that cortisol levels below ∼10 nmol/L weakly influenced connectivity between the identified regions.

DISCUSSION

The results indicate a dose-dependent association between cortisol levels and the rsFC of the visual cortex to several lateral brain regions associated with perception, attention, cognition, salience mapping and motor actions. It is possible that the effects of cortisol on cognitive functions may be (at least partially) mediated by cortisol effects on the underlying sensory processes.

The MAOA Gene Influences the Neural Response to Psychosocial Stress in the Human Brain

The stress response is regulated by many mechanisms. Monoamine oxidase A (MAOA) has been related to many mental illnesses. However, few studies have explored the relationship between MAOA and acute laboratory-induced psychosocial stress with functional magnetic resonance imaging (fMRI). In the current study, the Montreal Imaging Stress Task (MIST) and fMRI were used to investigate how MAOA influences the stress response. Increased cortisol concentrations were observed after the task; functional connectivity between the bilateral anterior hippocampus and other brain regions was reduced during stress. MAOA-H allele carriers showed greater deactivation of the right anterior hippocampus and greater cortisol response after stress than did MAOH-L allele carriers. Hippocampal deactivation may lead to disinhibition of the hypothalamic-pituitary-adrenal (HPA) axis and the initiation of stress hormone release under stress. Our results suggest that the MAOA gene regulates the stress response by influencing the right anterior hippocampus.

Spatial patterns of intrinsic brain activity and functional connectivity in facial synkinesis patients

Objectives: As one of the most objectionable sequelae of facial paralysis, patients with facial synkinesis are more likely to be depressed and have lower quality of life than other facial paralysis patients. However, there is no research on the spatial patterns of intrinsic brain activity and functional connectivity in these patients. The objective of this study was to investigate the spatial patterns and cerebral plasticity of facial synkinesis patients.Methods: A total of 20 facial synkinesis patients (18 men and 2 women; mean age: 33.35 ± 6.97 years old) and 19 healthy controls (17 men and 2 women; mean age: 33.21 ± 6.75 years old) were enrolled in this study. resting-state functional magnetic resonance imaging (rs-fMRI) data were collected, and the amplitude of low frequency fluctuation (ALFF), regional homogeneity (ReHo), and degree centrality (DC) were calculated for each participant. Two-sample t-tests were performed to compare the ALFF, ReHo, and DC maps between the two groups.Results: Compared with the healthy controls, facial synkinesis patients exhibited decreased ALFF in the fusiform gyrus, lingual gyrus, parahippocampal gyrus, triangular inferior frontal gyrus, precentral gyrus, postcentral gyrus, cingulate gyrus, superior frontal gyrus, precuneus, caudate nucleus and thalamus; decreased ReHo in the cingulate gyrus, superior frontal gyrus, insula, superior temporal gyrus, orbital middle frontal gyrus, caudate nucleus and thalamus; and decreased DC in the frontal lobe, insula, cingulate gyrus, superior temporal gyrus, lenticular putamen, hippocampus and parahippocampal gyrus. We found significant overlap in the superior frontal gyrus across the ALFF, ReHo and DC analyses.Conclusions: In facial synkinesis patients, the neurological activity in brain areas is reduced and the local synchronization in motion-related brain regions is decreased. The superior frontal gyrus could be a crucial region in the unique spatial patterns of intrinsic brain activity and functional connectivity in these patients.

Influence of psychosocial stress on activation in human brain regions: moderation by the 5-HTTLPR genetic locus

Variants of the serotonin transporter linked polymorphic region (5-HTTLPR) of the serotonin transporter gene SLC6A4 have been related with the onset of depression, anxiety, and other mental disorders. Homozygotes for the short 5-HTTLPR variant, referred to as the SS genotype, have greater cortisol responses to experimentally induced psychosocial stress. In the current study, we used functional magnetic resonance imaging (fMRI) to compare regional brain activations across 5-HTTLPR genotypes in subjects performing the Montreal Imaging Stress Task (MIST). Subjects with an SS genotype had significant greater increases in cortisol concentrations after the task than subjects with at least one long 5-HTTLPR allele. Additionally, relative to L carriers, the SS group had greater activation in the dorsomedial prefrontal cortex(dmPFC), dorsal anterior cingulate cortex, anterior insula.

Stress-induced changes in modular organizations of human brain functional networks

Humans inevitably go through various stressful events, which initiates a chain of neuroendocrine reactions that may affect brain functions and lead to psychopathological symptoms. Previous studies have shown stress-induced changes in activation of individual brain regions or pairwise inter-regional connectivity. However, it remains unclear how large-scale brain network is reconfigured in response to stress. Using a within-subjects design, we combined the Trier Social Stress Test and graph theoretical method to characterize stress-induced topological alterations of brain functional network. Modularity analysis revealed that the brain network can be divided into frontoparietal, default mode, occipital, subcortical, and central-opercular modules under control and stress conditions, corresponding to several well-known functional systems underpinning cognitive control, self-referential mental processing, visual, salience processing, sensory and motor functions. While the frontoparietal module functioned as a connector module under stress, its within-module connectivity was weakened. The default mode module lost its connector function and its within-module connectivity was enhanced under stress. Moreover, stress altered the capacity to control over information flow in a few regions important for salience processing and self-referential metal processing. Furthermore, there was a trend of negative correlation between modularity and stress response magnitude. These findings demonstrate that acute stress prompts large-scale brain-wide reconfiguration involving multiple functional modules.

The biological classification of mental disorders (BeCOME) study: a protocol for an observational deep-phenotyping study for the identification of biological subtypes

BACKGROUND

A major research finding in the field of Biological Psychiatry is that symptom-based categories of mental disorders map poorly onto dysfunctions in brain circuits or neurobiological pathways. Many of the identified (neuro) biological dysfunctions are "transdiagnostic", meaning that they do not reflect diagnostic boundaries but are shared by different ICD/DSM diagnoses. The compromised biological validity of the current classification system for mental disorders impedes rather than supports the development of treatments that not only target symptoms but also the underlying pathophysiological mechanisms. The Biological Classification of Mental Disorders (BeCOME) study aims to identify biology-based classes of mental disorders that improve the translation of novel biomedical findings into tailored clinical applications.

METHODS

BeCOME intends to include at least 1000 individuals with a broad spectrum of affective, anxiety and stress-related mental disorders as well as 500 individuals unaffected by mental disorders. After a screening visit, all participants undergo in-depth phenotyping procedures and omics assessments on two consecutive days. Several validated paradigms (e.g., fear conditioning, reward anticipation, imaging stress test, social reward learning task) are applied to stimulate a response in a basic system of human functioning (e.g., acute threat response, reward processing, stress response or social reward learning) that plays a key role in the development of affective, anxiety and stress-related mental disorders. The response to this stimulation is then read out across multiple levels. Assessments comprise genetic, molecular, cellular, physiological, neuroimaging, neurocognitive, psychophysiological and psychometric measurements. The multilevel information collected in BeCOME will be used to identify data-driven biologically-informed categories of mental disorders using cluster analytical techniques.

DISCUSSION

The novelty of BeCOME lies in the dynamic in-depth phenotyping and omics characterization of individuals with mental disorders from the depression and anxiety spectrum of varying severity. We believe that such biology-based subclasses of mental disorders will serve as better treatment targets than purely symptom-based disease entities, and help in tailoring the right treatment to the individual patient suffering from a mental disorder. BeCOME has the potential to contribute to a novel taxonomy of mental disorders that integrates the underlying pathomechanisms into diagnoses.

TRIAL REGISTRATION

Retrospectively registered on June 12, 2019 on ClinicalTrials.gov (TRN: NCT03984084).

Proposing a convolutional neural network for stress assessment by means of derived heart rate from functional near infrared spectroscopy

BACKGROUND

Stress is known as one of the major factors threatening human health. A large number of studies have been performed in order to either assess or relieve stress by analyzing the brain and heart-related signals.

METHOD

In this study, a method based on the Convolutional Neural Network (CNN) approach is proposed to assess stress induced by the Montreal Imaging Stress Task. The proposed model is trained on the heart rate signal derived from functional Near-Infrared Spectroscopy (fNIRS), which is referred to as HRF. In this regard, fNIRS signals of 20 healthy volunteers were recorded using a configuration of 23 channels located on the prefrontal cortex. The proposed deep learning system consists of two main parts where in the first part, the one-dimensional convolutional neural network is employed to build informative activation maps, and then in the second part, a stack of deep fully connected layers is used to predict the stress existence probability. Thereafter, the employed CNN method is compared with the Dense Neural Network, Support Vector Machine, and Random Forest regarding various classification metrics.

RESULTS

Results clearly showed the superiority of CNN over all other methods. Additionally, the trained HRF model significantly outperforms the model trained on the filtered fNIRS signals, where the HRF model could achieve 98.69 ± 0.45% accuracy, which is 10.09% greater than the accuracy obtained by the fNIRS model.

CONCLUSIONS

Employment of the proposed deep learning system trained on the HRF measurements leads to higher stress classification accuracy than the accuracy reported in the existing studies where the same experimental procedure has been done. Besides, the proposed method suggests better stability with lower variation in prediction. Furthermore, its low computational cost opens up the possibility to be applied in real-time monitoring of stress assessment.

Cognitive load amplifies Parkinson’s tremor through excitatory network influences onto the thalamus

Parkinson’s tremor is related to cerebral activity in both the basal ganglia and a cerebello-thalamo-cortical circuit. It is a common clinical observation that tremor markedly increases during cognitive load (such as mental arithmetic), leading to serious disability. Previous research has shown that this tremor amplification is associated with reduced efficacy of dopaminergic treatment. Understanding the mechanisms of tremor amplification and its relation to catecholamines might help to better control this symptom with a targeted therapy. We reasoned that, during cognitive load, tremor amplification might result from modulatory influences onto the cerebello-thalamo-cortical circuit controlling tremor amplitude, from the ascending arousal system (bottom-up), a cognitive control network (top-down), or their combination. We have tested these hypotheses by measuring concurrent EMG and functional MRI in 33 patients with tremulous Parkinson’s disease, OFF medication, during alternating periods of rest and cognitive load (mental arithmetic). Simultaneous heart rate and pupil diameter recordings indexed activity of the arousal system (which includes noradrenergic afferences). As expected, tremor amplitude correlated with activity in a cerebello-thalamo-cortical circuit; and cognitive load increased tremor amplitude, pupil diameter, heart rate, and cerebral activity in a cognitive control network distributed over fronto-parietal cortex, insula, thalamus and anterior cingulate cortex. The novel finding, obtained through network analyses, indicates that cognitive load influences tremor by increasing activity in the cerebello-thalamo-cortical circuit in two different ways: by stimulating thalamic activity, likely through the ascending arousal system (given that this modulation correlated with changes in pupil diameter), and by strengthening connectivity between the cognitive control network and the cerebello-thalamo-cortical circuit. We conclude that both the bottom-up arousal system and a top-down cognitive control network amplify tremor when a Parkinson’s patient experiences cognitive load. Interventions aimed at attenuating noradrenergic activity or cognitive demands may help to reduce Parkinson’s tremor.

Increasing Deactivation of Limbic Structures Over Psychosocial Stress Exposure Time

BACKGROUND

Understanding the interplay between central nervous system and hypothalamic-pituitary-adrenal axis responses to stress in humans is assumed to be essential to contribute to the central question of stress research, namely how stress can increase disease risk. Therefore, the present study used a neuroimaging stress paradigm to investigate the interplay of 3 stress response domains. Furthermore, we asked if the brain's stress response changes over exposure time.

METHODS

In a functional magnetic resonance imaging study, changes in brain activation, cortisol levels, affect, and heart rate in response to an improved ScanSTRESS protocol were assessed in 67 young, healthy participants (31 females).

RESULTS

Stress exposure led to significant increases in cortisol levels, heart rate, and negative affect ratings as well as to activations and deactivations in (pre)limbic regions. When cortisol increase was used as a covariate, stronger responses in the hippocampus, amygdala, medial prefrontal cortex, and cingulate gyrus were observed. Responses within the same regions predicted negative affect ratings. Remarkably, an increasing deactivation over the two ScanSTRESS runs was found, again, in the same structures. A reanalysis of an independent sample confirmed this finding.

CONCLUSIONS

For the first time, reactions in a cluster of (pre)limbic structures was consistently found to be associated with changes in cortisol and negative affect. The same neural structures showed increasing deactivations over stress exposure time. We speculate that investigating possible associations between exposure-time effects in neural stress responses and stress-related interindividual differences (e.g., chronic stress) might be a promising new avenue in stress research.

Cognitive appraisal in fish: stressor predictability modulates the physiological and neurobehavioural stress response in sea bass

The role of cognitive factors in triggering the stress response is well established in humans and mammals (aka cognitive appraisal theory) but very seldom studied in other vertebrate taxa. Predictability is a key factor of the cognitive evaluation of stimuli. In this study, we tested the effects of stressor predictability on behavioral, physiological and neuromolecular responses in the European sea bass (Dicentrarchus labrax). Groups of four fish were exposed to a predictable (signalled) or unpredictable (unsignalled) stressor. Stressor predictability elicited a lower behavioural response and reduced cortisol levels. Using the expression of immediate early genes (c-fos, egr-1, bdnf and npas4) as markers of neuronal activity, we monitored the activity of three sea bass brain regions known to be implicated in stressor appraisal: the dorsomedian telencephalon, Dm (putative homologue of the pallial amygdala); and the dorsal (Dld) and ventral (Dlv) subareas of the dorsolateral telencephalon (putative homologue of the hippocampus). The activity of both the Dm and Dlv significantly responded to stressor predictability, suggesting an evolutionarily conserved role of these two brain regions in information processing related to stressor appraisal. These results indicate that stressor predictability plays a key role in the activation of the stress response in a teleost fish, hence highlighting the role of cognitive processes in fish stress.

Balancing Between Goal-Directed and Habitual Responding Following Acute Stress

Abstract. Instrumental learning is regulated by two memory systems: a relatively rigid but efficient habit system and a flexible but resource-demanding goal-directed system. Previous work has demonstrated that exposure to acute stress may shift the balance between these systems toward the habitual system. In the current study, we used a 2-day outcome devaluation paradigm with a 75% reward contingency rate and altered food reward categories to replicate and extend our previous findings. Participants learned neutral stimulus–response–reward associations on the first day. On the second day, rewards were devalued by eating to satiety. Subsequently, acute stress was induced in half of the participants using the Maastricht Acute Stress Test, while the other half engaged in a nonstressful control task. Finally, relative goal-directed versus habitual behavior was evaluated in a slips-of-action phase, where more slips-of-action indicate a shift toward the habitual system. Results showed that participants successfully acquired the stimulus–response–reward associations, that devaluation was effective, and that stressed participants displayed significant increases in cortisol and blood pressure. Stress led participants to commit more slips-of-action compared with nonstressed controls. The current study extends previous work, showing that the employed paradigm and outcome devaluation procedure are boundary conditions to the stress-induced shift in instrumental responding.

Neuroticism modulates neural activities of posterior cingulate cortex and thalamus during psychosocial stress processing

OBJECTIVE

Individuals with higher neuroticism are vulnerable to stress and are prone to develop depression, however, the neural mechanisms underlying it have not been clarified clearly.

METHOD

The Montreal Imaging Stress Task (MIST) was administered to 148 healthy adults during functional magnetic resonance imaging (fMRI). Whole-brain voxel-wise regression analyses were used to detect associations of neuroticism with neural activity involved in perceiving and processing psychosocial stress. In addition, two-sample t-tests were conducted between the high-neurotic and low-neurotic group in order to supplement the results found in regression analyses.

RESULTS

Higher neuroticism scores were associated with higher activities in the posterior cingulate cortex (PCC)/precuneus and thalamus (p < 0.05, false discovery rate correction). Moreover, two sample t-tests also revealed that the high-neurotic group had higher neural stress responses in precuneus and bilateral thalamus in comparison to the low-neurotic group (p < 0.05, false discovery rate correction).

LIMITATIONS

Our study mainly recruited young adults, which may limit the generalizability of our findings.

CONCLUSIONS

Our findings highlight the crucial role of PCC/precuneus and thalamus in the association between neuroticism and stress and may provide insight into the cognitive model of depression.

Estradiol administration differentially affects the response to experimental psychosocial stress in post-menopausal women with or without a history of major depression

BACKGROUND:

The effects of estradiol on the brain regions involved in the response to stress and emotional processes may be particularly important in women who have alterations in these systems that make them vulnerable to Major Depressive Disorder (MDD). This study examined whether the effect of estradiol administration on the subjective distress and mood response to a laboratory-based psychosocial stress task differs in women with and without a history of MDD.

METHODS:

Participants were 65 euthymic postmenopausal women, with and without a history of MDD. They received either 3 months of open-label oral estradiol or did not receive estradiol. After 3 months, participants completed the Montreal Stress Imaging Task (MIST) and subjective distress and mood ratings.

RESULTS:

The effect of estradiol on subjective distress following the MIST differed based on MDD history. In women without a history of MDD, estradiol administration was associated with greater subjective distress than no estradiol. However, in women with a history of MDD, estradiol administration was associated with less subjective distress compared to no estradiol.

LIMITATIONS:

This study included open-label administration of estradiol and participants were not blinded to administration. Interpretation of result should include consideration of the relatively small group sizes and that results may not generalize to currently depressed individuals.

CONCLUSIONS:

In euthymic women with a history of MDD, estradiol may benefit the affective response to psychosocial stress while having comparatively little benefit in women with no MDD history. Further work should explore whether estradiol administration reduces the risk of depression recurrence in post-menopausal women with past MDD.

Childhood Maltreatment Experience Influences Neural Response to Psychosocial Stress in Adults: An fMRI Study

Background

Childhood maltreatment is a strong risk factor for the development of depression in later life. However, the neurobiological mechanisms underlying this vulnerability are not well understood. As depression has been associated with dysfunction of the hypothalamic-pituitary-adrenal (HPA) axis and increased responsiveness to psychosocial stressors, we speculated that childhood maltreatment may lead to lasting alteration of the stress response system, thereby increasing the risk of depression. This study investigated the effects of childhood maltreatment on the stress response in healthy subjects while controlling for psychiatric condition.

Methods

Forty-eight healthy young adults (24 females) with childhood maltreatment experience and 48 healthy controls (33 females) without such experience were administered the Montreal Imaging Stress Task during functional magnetic resonance imaging. Childhood maltreatment experience was assessed using the 28-item Childhood Trauma Questionnaire (CTQ). Between-group differences in subjective stress levels, whole brain activations and cortisol levels were assessed.

Results

Relative to healthy control subjects, individuals exposed to childhood maltreatment exhibited higher subjective stress and cortisol levels. Neurofunctionally, participants with histories of childhood maltreatment displayed significantly increased activation in the dorsolateral prefrontal cortex (dlPFC), insula and precuneus, and decreased activation in ventromedial prefrontal cortex (vmPFC) relative to healthy controls during the psychosocial stress task. Activations in dlPFC and insula correlated with CTQ scores in the childhood maltreatment group.

Conclusion

The results of this study show that childhood maltreatment induces lasting changes in brain function and HPA-axis responsiveness to stress. The observed abnormal activation in the dlPFC, insula and vmPFC and enhanced cortisol response are similar to those seen in individuals with depression. This dysfunction might serve as a diathesis that embeds latent vulnerability to psychiatric disorders, and this mechanism provides evidence supporting the stress sensitization model.

Blocking under stress: Sustained attention to stimuli without predictive value?

Learning is blocked when a stimulus is followed by an outcome that is identical to what was expected and thus contains no new information. This classic 'blocking' effect exemplifies that learning is driven by the predictive value of stimuli, which in turn should guide the allocation of attentional resources. Stress is known to be a powerful modulator of learning and memory. However, whether stress may affect attentional processing during predictive learning is largely unknown. Here, we combined electroencephalography and eye-tracking with an experimental stress manipulation and a fear conditioning paradigm designed to probe the blocking effect, to determine if and how stress impacts efficient attentional processing during predictive learning. Participants' explicit ratings indicated, irrespective of stress, a blocking effect. The control group further showed preferential attentional processing of predictive vs. unpredictive stimuli, reflected in differential fixation durations and a differential N2pc. Stress abolished this differentiation and led even to sustained attention, indicated by higher late positive potentials, to stimuli with low predictive value. Moreover, stress resulted in an overall increase in the P3b during the blocking phase, suggesting increased attentional processing, presumably due to impaired access to previously learned associations. Together, our results suggest that while control participants paid particular attention to predictive stimuli and reduced attention to unpredictive stimuli, in line with the classic blocking effect, stress before learning reduced this preferential processing. Thus, the present findings highlight the role of attention allocation for predictive fear learning and suggest that stress may impair efficient information processing against the background of prior experiences.

Exercise and Anxiety

Anxiety disorders are a group of highly prevalent mental health conditions that can have a debilitating impact on daily functioning and well-being. They can co-occur with other mental health disorders, such as depression. People with anxiety disorders are also at an elevated risk of cardiovascular disease and premature mortality. Physical activity appears to be protective against anxiety disorders in clinical and nonclinical populations. Exercise, a subset of physical activity, has been shown to significantly reduce the symptoms of anxiety. The mechanisms through which exercise produces these effects are likely to involve a combination of biological and psychological factors. Physical activity may also be useful in reducing the symptoms of comorbid mental health conditions and the risk of physical health complications over time. Promoting physical activity could be a method of preventing or treating anxiety disorders with a wide range of benefits. However, further research will be necessary to address important gaps in the literature before these approaches can be fully implemented in mental health services.

Childhood Maltreatment Alters the Neural Processing of Chemosensory Stress Signals

Accumulating evidence suggests that childhood maltreatment (CM) confers risk for psychopathology later in life by inducing hypervigilance to social threat cues such as fearful faces. However, it remains unclear whether the modulatory impact of CM extents to the olfactory domain of social communication in humans. To address this question, we examined whether CM modulates the neural processing of chemosensory threat signals in sweat and whether CM affects the stress-reducing effects of oxytocin (OXT) in this context. In a randomized, double-blind within-subject functional MRI study design, 58 healthy participants (30 females) received intranasal OXT (40 IU) or placebo (PLC) and completed a forced-choice emotion recognition task with faces of varying emotion intensities (neutral to fearful) while exposed to sweat stimuli and a non-social control odor. Axillary sweat samples were collected from 30 healthy male donors undergoing an acute psychosocial stressor (stress) and ergometer training (sport) as control in a pre-study. CM was assessed by the 25-item Childhood Trauma Questionnaire (CTQ). The final fMRI analysis included 50 healthy participants (26 females). Regression analysis showed a stress-specific association of CTQ scores with amygdala hyperreactivity, hippocampal deactivation, and increased functional connectivity between the amygdala and the hippocampus, medial orbitofrontal cortex, and the anterior cingulate cortex (ACC) under PLC. Furthermore, we observed a positive association of CTQ scores and the dampening effects of OXT on stress-related amygdala responses. Our findings suggest that CM may induce hypervigilance to chemosensory threat cues in a healthy sample due to inefficient frontolimbic inhibition of amygdala activation. Future studies should investigate whether increased recruitment of the intralimbic amygdala-hippocampus complex reflects a compensatory mechanism that prevents the development of psychopathology in those who have experienced CM. Furthermore, the results reveal that the stress-specific effects of OXT in the olfactory domain are more pronounced in participants with increasing levels of CM exposure.

Increased BNST reactivity to affective images is associated with greater α-amylase response to social stress

While rodent research suggests that the bed nucleus of the stria terminalis (BNST) and centromedial amygdala (CM) coordinate the hormonal stress response, little is known about the BNST’s role in the human stress response. The human BNST responds to negatively valenced stimuli, which likely subserves its role in responding to threat. Thus, variation in BNST reactivity to negatively valenced stimuli may relate to differences in the stress response. We measured participants’ blood oxygenated level-dependent response to affective images and salivary cortisol and α-amylase (AA) levels in response to a subsequent Trier social stress test (TSST). Greater BNST activation to emotionally evocative images was associated with a larger TSST-evoked AA, but not cortisol response. This association remained after controlling for CM activation, which was not related to the cortisol or AA response. These results suggest that the BNST response to negatively valenced images subserves its role in coordinating the stress response, a BNST role in the stress response independent from the CM, and highlight the need for investigation of the conditions under which BNST activation predicts the cortisol response. Our findings are critical for the future study of mood and anxiety disorders, as dysregulation of the stress system plays a key role in their pathogenesis.

Effects of stress on functional connectivity during verbal processing

Effects of stress on functional connectivity (FC) in specific language processing regions of the brain during verbal fluency tasks were explored. Roles of gender and serotonin transporter gene polymorphisms (5-HTTLPR), associated with stress susceptibility, were also examined to understand their effect. Forty-five healthy volunteers (Mean age: 19.6 ± 1.6 years; 28 females) participated. Functional magnetic resonance imaging was carried out while participants performed letter and category fluency tasks. These tasks were interposed with the Montreal Imaging Stress Test to induce stress or a no-stress control task. Buccal swabs collected were used to genotype for the presence of polymorphisms on the SLC6A4 gene known to contribute to atypical stress responses. Significant variations in strength of FC were noted between several ROIs, including left inferior frontal gyrus and left middle temporal gyrus. Overall, males showed regional increases in FC strength over long and short distances during task under stress. Additionally, variability in effects of stress on task performance was associated with effects of stress on FC. Results suggest that long distance FC may be strengthened to compensate for additional cognitive load of the stressor but that specific short distance functional connections may be strengthened in a gender specific manner. Additionally, FC may serve as a marker for effects of stress on performance. This is the first study exploring stress effects on language tasks with imaging markers. Future studies will need to explore stress susceptible populations and establish the role of FC as a marker, with implications for targeted therapeutic interventions.

Brain dynamics and connectivity networks under natural auditory stimulation

The analysis of functional magnetic resonance imaging (fMRI) data is challenging when subjects are under exposure to natural sensory stimulation. In this study, a two-stage approach was developed to enable the identification of connectivity networks involved in the processing of information in the brain under natural sensory stimulation. In the first stage, the degree of concordance between the results of inter-subject and intra-subject correlation analyses is assessed statistically. The microstructurally (i.e., cytoarchitectonically) defined brain areas are designated either as concordant in which the results of both correlation analyses are in agreement, or as discordant in which one analysis method shows a higher proportion of supra-threshold voxels than does the other. In the second stage, connectivity networks are identified using the time courses of supra-threshold voxels in brain areas contingent upon the classifications derived in the first stage. In an empirical study, fMRI data were collected from 40 young adults (19 males, average age 22.76 ± 3.25), who underwent auditory stimulation involving sound clips of human voices and animal vocalizations under two operational conditions (i.e., eyes-closed and eyes-open). The operational conditions were designed to assess confounding effects due to auditory instructions or visual perception. The proposed two-stage analysis demonstrated that stress modulation (affective) and language networks in the limbic and cortical structures were respectively engaged during sound stimulation, and presented considerable variability among subjects. The network involved in regulating visuomotor control was sensitive to the eyes-open instruction, and presented only small variations among subjects. A high degree of concordance was observed between the two analyses in the primary auditory cortex which was highly sensitive to the pitch of sound clips. Our results have indicated that brain areas can be identified as concordant or discordant based on the two correlation analyses. This may further facilitate the search for connectivity networks involved in the processing of information under natural sensory stimulation.

Altered Cerebro-Cerebellar Limbic Network in AD Spectrum: A Resting-State fMRI Study

Recent evidence suggests that the cerebellum is related to motor and non-motor cognitive functions, and that several coupled cerebro-cerebellar networks exist, including links with the limbic network. Since several limbic structures are affected by Alzheimer pathology, even in the preclinical stages of Alzheimer’s disease (AD), we aimed to investigate the cerebral limbic network activity from the perspective of the cerebellum. Twenty patients with mild cognitive impairment (MCI), 18 patients with AD, and 26 healthy controls (HC) were recruited to acquire Resting-state functional MRI (rs-fMRI). We used seed-based approach to construct the cerebro-cerebellar limbic network. Two-sample t-tests were carried out to explore the differences of the cerebellar limbic network connectivity. The first result, a sub-scale network including the bilateral posterior part of the orbitofrontal cortex (POFC) extending to the anterior insular cortex (AIC) and left inferior parietal lobule (L-IPL), showed greater functional connectivity in MCI than in HC and less functional connectivity in AD than in MCI. The location of this sub-scale network was in accordance with components of the ventral attention network. Second, there was decreased functional connectivity to the right mid-cingulate cortex (MCC) in the AD and MCI patient groups relative to the HC group. As the cerebellum is not compromised by Alzheimer pathology in the prodromal stage of AD, this pattern indicates that the sub-scale ventral attention network may play a pivotal role in functional compensation through the coupled cerebro-cerebellar limbic network in MCI, and the cerebellum may be a key node in the modulation of social cognition.

Neurobiological mechanisms underlying sex-related differences in stress-related disorders: Effects of neuroactive steroids on the hippocampus

Men and women differ in their vulnerability to a variety of stress-related illnesses, but the underlying neurobiological mechanisms are not well understood. This is likely due to a comparative dearth of neurobiological studies that assess male and female rodents at the same time, while human neuroimaging studies often don't model sex as a variable of interest. These sex differences are often attributed to the actions of sex hormones, i.e. estrogens, progestogens and androgens. In this review, we summarize the results on sex hormone actions in the hippocampus and seek to bridge the gap between animal models and findings in humans. However, while effects of sex hormones on the hippocampus are largely consistent in animals and humans, methodological differences challenge the comparability of animal and human studies on stress effects. We summarise our current understanding of the neurobiological mechanisms that underlie sex-related differences in behavior and discuss implications for stress-related illnesses.

Increased Posterior Cingulate Functional Connectivity Following 6-Month High-Dose B-Vitamin Multivitamin Supplementation: A Randomized, Double-Blind, Placebo-Controlled Trial

B vitamins are essential for optimal brain and body function, and are particularly important for cortical metabolic processes that have downstream effects on mitigating oxidative stress. Oxidative stress has been linked to poor psychological outcomes including psychological distress, which has wide-reaching implications for the community and the workplace. Given work-related stress has been associated with poor mental health outcomes, high-dose B vitamin supplementation may be effective in improving brain function and psychological outcomes via attenuation of oxidative stress. This randomized, double-blind, placebo-controlled study investigated psychological outcomes following 6-month supplementation of a high-B-vitamin multivitamin in a large sample of healthy adults (n = 108, aged 30-70 years), as well as changes in default mode network functional connectivity in a subset of the original sample (n = 28). Improvements in occupational stress, general health, perceived stress, depressive symptoms, and mood profiles were identified for both active and placebo groups over time (p < 0.05 corrected). Seed-based functional connectivity analysis centered on the posterior cingulate cortex (PCC) showed that connectivity between the PCC and the caudate increased for the active treatment group, but decreased for the placebo group (p < 0.05 corrected). These findings reveal a substantial intervention effect for both active and placebo treatments, which could in part be associated with a placebo effect in subjective measures. There was, however, a significant treatment effect in the objective measure of functional connectivity, suggesting that reduced psychological stress and high-B-vitamin multivitamin supplementation may lead to an increase in DMN and caudate functional connectivity, which might reflect a strengthening of neurocircuitry within areas associated with reward and emotion at rest. Future studies should consider a placebo run-in methodology to reduce the placebo effect on the subjective measures of stress.

A Functional Near-Infrared Spectroscopy Study on the Cortical Haemodynamic Responses During the Maastricht Acute Stress Test

In order to better understand stress responses, neuroimaging studies have investigated the underlying neural correlates of stress. Amongst other brain regions, they highlight the involvement of the prefrontal cortex. The aim of the present study was to explore haemodynamic changes in the prefrontal cortex during the Maastricht Acute Stress Test (MAST) using mobile functional Near-Infrared Spectroscopy (fNIRS), examining the stress response in an ecological environment. The MAST includes a challenging mental arithmic task and a physically stressful ice-water task. In a between-subject design, participants either performed the MAST or a non-stress control condition. FNIRS data were recorded throughout the test. Additionally, subjective stress ratings, heart rate and salivary cortisol were evaluated, confirming a successful stress induction. The fNIRS data indicated significantly increased neural activity of brain regions of the dorsolateral prefrontal cortex (dlPFC) and the orbitofrontal cortex (OFC) in response to the MAST, compared to the control condition. Furthermore, the mental arithmetic task indicated an increase in neural activity in brain regions of the dlPFC and OFC; whereas the physically stressful hand immersion task indicated a lateral decrease of neural activity in the left dlPFC. The study highlights the potential use of mobile fNIRS in clinical and applied (stress) research.

Stress and the brain: Perceived stress mediates the impact of the superior frontal gyrus spontaneous activity on depressive symptoms in late adolescence

Identifying factors for the prediction of depression is a long-standing research topic in psychiatry and psychology. Perceived stress, which reflects the tendency to appraise one's life situations as stressful and overwhelming, has emerged as a stable predictor for depressive symptoms. However, the neurobiological bases of perceived stress and how perceived stress influences depressive symptoms in the healthy brain remain largely unknown. Here, we investigated these issues in 217 healthy adolescents by estimating the fractional amplitude of low-frequency fluctuations (fALFFs) via resting-state functional magnetic resonance imaging. A whole-brain correlation analysis showed that higher levels of perceived stress were associated with greater fALFF in the left superior frontal gyrus (SFG), which is a core brain region for cognitive control and emotion regulation-related processes. Mediation analysis further indicated that perceived stress mediated the link between the fALFF in the left SFG and depressive symptoms. Importantly, our results remained significant even when excluding the influences of head motion, anxiety, SFG gray matter structure, and school environment. Altogether, our findings suggested that the fALFF in the left SFG is a neurofunctional marker of perceived stress in adolescents and revealed a potential indirect effect of perceived stress on the association between the SFG spontaneous activity and depressive symptoms.

FMRI response to acute psychological stress differentiates patients with psychogenic non-epileptic seizures from healthy controls - A biochemical and neuroimaging biomarker study

We investigated psychological stress response in the brain regions involved in emotion-motor-executive control in psychogenic non-epileptic seizures (PNES). 12 PNES patients and 12 healthy controls (HCs) underwent stress task and resting state functional MRI (fMRI), mood and quality of life (QOL) assessments, and measurements of salivary cortisol, alpha-amylase, and heart rate. Group differences were assessed, and we correlated beta values from a priori selected brain regions showing stress task fMRI group differences with other stress response measures. We also used the regions showing stress task fMRI group differences as seeds for resting state functional connectivity (rs-FC) analysis. Mood and QOL were worse in PNES versus HCs. Physiological and assessment measures were similar except 'Planful Problem Solving' coping that was greater for HCs (p = .043). Perceived stress associated negatively with heart rate change (r_s = -0.74, p = .0063). There was stress fMRI hyporeactivity in left/right amygdala and left hippocampus in PNES versus HCs (corrected p < .05). PNES exhibited a positive association between alpha-amylase change and right amygdala activation (r_s = 0.71, p = .010). PNES versus HCs exhibited greater right amygdala rs-FC to left precentral and inferior/middle frontal gyri (corrected p < .05). Our findings of fMRI hyporeactivity to psychological stress, along with greater emotion-motor-executive control network rs-FC in PNES when compared to HCs suggest a dysregulation in stress response circuitry in PNES.

An initial investigation of neonatal neuroanatomy, caregiving, and levels of disorganized behavior

Attachment disorganization is a risk factor for difficulties in attention, social relationships, and mental health. Conceptually, attachment disorganization may indicate a breakdown in fear regulation resulting from repeated exposure to frightening maternal care. In addition, past research has examined the influence of stress-inducing contextual factors and/or child factors upon the development of disorganization. However, no past work has assessed whether infant neuroanatomy, important to stress regulation, moderates the association between maternal care and levels of disorganized behavior. Here, utilizing data from a subsample of 82 dyads taking part in the "Growing Up in Singapore towards Healthy Outcomes" (GUSTO) cohort, we assessed the prediction from maternal sensitive caregiving at 6 mo and levels of attachment disorganization at 1.5 y, as moderated by hippocampal and amygdala volume determined within the first 2 weeks of life. Results indicate a significant interaction between neonatal left hippocampal volume and maternal sensitivity upon levels of disorganized behavior. Although these results require substantiation in further research, if replicated, they may enable new strategies for the identification of processes important to child mental health and points for intervention. This is because neonatal neuroanatomy, as opposed to genetic variation and sociodemographic risk, may be more directly linked to stress responses within individuals.

Resting-state functional connectivity after hydrocortisone administration in patients with post-traumatic stress disorder and borderline personality disorder

In a previous study, we found that - in contrast to healthy individuals - patients with borderline personality disorder (BPD) and post-traumatic stress disorder (PTSD) showed better memory retrieval performance after hydrocortisone administration compared to placebo. As these results suggest an altered function of corticosteroid receptors in the brain in PTSD and BPD, we examined the effect of hydrocortisone on brain activation in both disorders. We recruited 40 female healthy controls, 20 female unmedicated patients with PTSD and 18 female unmedicated patients with BPD. We conducted a placebo-controlled cross-over study, in which all participants underwent two resting state MRI measurements after they received either a placebo or 10 mg hydrocortisone orally and in randomized order. There was a time interval of one week between the measurements. We analysed resting state functional connectivity (RSFC) with the hippocampus and the amygdala as seed regions. Compared to healthy controls, both patient groups showed reduced hippocampus RSFC to dorsomedial prefrontal cortex (dmPFC). Positive hippocampus dmPFC RSFC correlated negatively with childhood trauma (r = -0.47) and with severity of clinical symptoms, measured with the Borderline Symptom List (r = -0.44) and the Posttraumatic Stress Diagnostic Scale (r = -0.45). We found neither differences in amygdala RSFC nor an effect of hydrocortisone administration. Childhood trauma might lead to decreased positive hippocampus dmPFC RSFC. This might explain symptoms of PTSD and BPD that are characterized by dysfunctional fear regulation.

Interactive effects of stress reactivity and rapid eye movement sleep theta activity on emotional memory formation

Sleep and stress independently enhance emotional memory consolidation. In particular, theta oscillations (4-7 Hz) during rapid eye movement (REM) sleep increase coherence in an emotional memory network (i.e., hippocampus, amygdala, and prefrontal cortex) and enhance emotional memory. However, little is known about how stress during learning might interact with subsequent REM theta activity to affect emotional memory. In the current study, we examined whether the relationship between REM theta activity and emotional memory differs as a function of pre-encoding stress exposure and reactivity. Participants underwent a psychosocial stressor (the Trier Social Stress Task; n = 32) or a comparable control task (n = 32) prior to encoding. Task-evoked cortisol reactivity was assessed by salivary cortisol rise from pre- to post-stressor, and participants in the stress condition were additionally categorized as high or low cortisol responders via a median split. During incidental encoding, participants studied 150 line drawings of negative, neutral, and positive images, followed by the complete color photo. All participants then slept overnight in the lab with polysomnographic recording. The next day, they were given a surprise recognition memory task. Results showed that memory was better for emotional relative to neutral information. Critically, these findings were observed only in the stress condition. No emotional memory benefit was observed in the control condition. In stressed participants, REM theta power significantly predicted memory for emotional information, specifically for positive items. This relationship was observed only in high cortisol responders. For low responders and controls, there was no relationship between REM theta and memory of any valence. These findings provide evidence that elevated stress at encoding, and accompanying changes in neuromodulators such as cortisol, may interact with theta activity during REM sleep to promote selective consolidation of emotional information.

Frontal Control Over Automatic Emotional Action Tendencies Predicts Acute Stress Responsivity

BACKGROUND

The ability to control social-emotional actions is relevant for everyday social interaction and may be indicative of responsiveness to actual social stress situations. This is particularly relevant for predicting stress responsiveness of the hypothalamic-pituitary-adrenal axis, known to be dysregulated in various stress-related affective disorders. Here we tested, in a large sample, whether reduced frontal control over social approach-avoidance actions can indeed signal increased hypothalamic-pituitary-adrenal axis reactivity to subsequent social stress exposure.

METHODS

A total of 279 subjects (214 men) participated in a functional magnetic resonance imaging social-emotional approach-avoidance task that involved impulsive and controlled emotional actions. Subsequently, participants underwent a stress induction including a socially evaluated cold pressor task and a mental arithmetic task. Salivary cortisol and α-amylase levels, as well as self-reported negative affect, were measured before and after stress induction.

RESULTS

Emotion control was successfully induced by the approach-avoidance task. Namely, instrumental overriding of automatic social approach-avoidance actions was associated with the typical increased bilateral anterior prefrontal cortex activation, longer reaction times, and more errors. Moreover, subsequent stress induction led to significant increases in all stress measures. Critically, bilateral anterior prefrontal cortex activation during emotion control was associated with reduced responses to the subsequent stressor in not only cortisol but also α-amylase and negative affect.

CONCLUSIONS

The ability to recruit prefrontal regions during social-emotion regulation predicts cortisol responses to an actual social stress situation. This finding provides the first evidence that instrumental control over social approach avoidance actions can signal stress responsiveness in major stress systems, providing a promising biomarker in stress vulnerability and resilience research relevant for affective disorders.

Affective Game Planning for Health Applications: Quantitative Extension of Gerontoludic Design Based on the Appraisal Theory of Stress and Coping

User retention is the first challenge in introducing any information and communication technologies (ICT) for health applications, particularly for seniors who are increasingly targeted as beneficiaries of such technologies. Interaction with digital technologies may be too stressful to older adults to guarantee their adoption in their routine selfcare. The second challenge, which also relates to adoption, is to supply empirical evidence that support the expectations of their beneficial outcomes. To address the first challenge, persuasive technologies such as serious games (SGs) are increasingly promoted as ludic approaches to deliver assistive care to older adults. However, there are no standards yet to assess the efficacy of different genres of games across populations, or compare and contrast variations in health outcomes arising from user interface design and user experience. For the past 3 decades, research has focused either on qualitative assessment of the appeal of digital games for seniors (by game designers) or on the quantitative evaluation of their clinical efficacy (by clinical researchers). The consensus is that interindividual differences play a key role in whether games can be useful or not for different individuals. Our challenge is to design SGs that retain their users long enough to sustain beneficial transfer effects. We propose to add a neuropsychological experimental framework (based on the appraisal theory of stress and coping) to a Gerontoludic design framework (that emphasizes designing positive and meaningful gaming experience over benefit-centric ones) in order to capture data to guide SG game development. Affective Game Planning for Health Applications (AGPHA) adds a model-driven mixed-methods experimental stage to a user-centered mechanics-dynamics-aesthetics game-design cycle. This intersectoral framework is inspired by latest trends in the fields of neuroimaging and neuroinformatics that grapple with similar challenges related to the psychobiological context of an individual's behaviors. AGPHA aims to bring users, designers, clinicians, and researchers together to generate a common data repository that consists of 4 components to define, design, evaluate, and document SGs. By unifying efforts under a standard approach, we will accelerate innovations in persuasive and efficacious ICTs for the aging population.

Acute psychosocial stress alters thalamic network centrality

Acute stress triggers a broad psychophysiological response that is adaptive if rapidly activated and terminated. While the brain controls the stress response, it is strongly affected by it. Previous research of stress effects on brain activation and connectivity has mainly focused on pre-defined brain regions or networks, potentially missing changes in the rest of the brain. We here investigated how both stress reactivity and stress recovery are reflected in whole-brain network topology and how changes in functional connectivity relate to other stress measures. Healthy young males (n = 67) completed the Trier Social Stress Test or a control task. From 60 min before until 105 min after stress onset, blocks of resting-state fMRI were acquired. Subjective, autonomic, and endocrine measures of the stress response were assessed throughout the experiment. Whole-brain network topology was quantified using Eigenvector centrality (EC) mapping, which detects central hubs of a network. Stress influenced subjective affect, autonomic activity, and endocrine measures. EC differences between groups as well as before and after stress exposure were found in the thalamus, due to widespread connectivity changes in the brain. Stress-driven EC increases in the thalamus were significantly correlated with subjective stress ratings and showed non-significant trends for a correlation with heart rate variability and saliva cortisol. Furthermore, increases in thalamic EC and in saliva cortisol persisted until 105 min after stress onset. We conclude that thalamic areas are central for information processing after stress exposure and may provide an interface for the stress response in the rest of the body and in the mind.

Pre-scan cortisol is differentially associated with enhanced connectivity to the cognitive control network in young adults with a history of depression

BACKGROUND

We have previously demonstrated that pre-scan salivary cortisol is associated with attentuated frontal-subcortical brain activation during emotion processesing and semantic list-learning paradigms in depressed subjects. Additionally, altered functional connectivity is observed after remission of acute depression symptoms (rMDD). It is unknown whether cortisol also predicts altered functional connectivity during remission.

METHODS

Participants were 47 healthy controls (HC) and 73 rMDD, 18-30 years old who provided salivary cortisol samples before and after undergoing resting-state fMRI. We tested whether salivary cortisol by diagnosis interactions were associated with seed-based resting connectivity of the default mode (DMN) and salience and emotion (SN) networks using whole-brain, cluster-level corrected (p < .01) regression in SPM8.

RESULTS

Pre-scan cortisol predicted decreased (HC) and increased (rMDD) cross-network connectivity to the dorsal anterior cingulate, dorso-medial and lateral- prefrontal cortex, brain stem and cerebellum (all seeds) and precuneus (DMN seeds). By and large, pre/post-scan cortisol change predicted the same pattern of findings. In network analyses, cortisol predominantly predicted enhanced cross-network connectivity to cognitive control network regions in rMDD.

CONCLUSIONS

The association of cortisol with connections of default and salience networks to executive brain networks differs between individuals with and without a history of depression. Further investigation is needed to better understand the role of cortisol and related stress hormones as a potential primary and interactive driver of network coherence in depression.

Temporal dynamic modulation of acute stress on error processing in healthy males

Error processing is critical for adaptive behaviors. Acute stress has been found to influence error processing. However, the neural dynamic correlates underlying this modulation remain elusive. To address this issue, we recruited 39 healthy male participants, who performed a two-session task before and after an acute stress test while their behavioral and EEG data were recorded. The participants were randomly exposed to either a stress condition (Maastricht Acute Stress Test) or a control condition. The stress test consisted of several hand immersion tasks (ice-cold water, 2°C) and mental arithmetic tasks. A color-word Stroop task was used to investigate the stress effect on error responses. Based on the level of stress-induced cortisol, the participants in the stress group were further classified as low (N = 13) or high (N = 13) cortisol responders. The results indicated that only in the high cortisol responders, the error-related negativity (ERN) amplitude was reduced after acute stress. In addition, the ∆ERN in the high cortisol responders was significantly smaller than that in the low cortisol responders. These results suggest that acute stress impairs error detection. However, the error positivity amplitudes increased in the stress group compared to the control group, indicating that acute stress leads to greater error assessment. Taken together, these results suggest that acute stress impairs error detection, which is modulated by individuals' response level following acute stress, and leads to more emotional and/or motivational responses to the error signal once the error is consciously realized.

Neonatal amygdalae and hippocampi are influenced by genotype and prenatal environment, and reflected in the neonatal DNA methylome

The amygdala and hippocampus undergo rapid development in early life. The relative contribution of genetic and environmental factors to the establishment of their developmental trajectories has yet to be examined. We performed imaging on neonates and examined how the observed variation in volume and microstructure of the amygdala and hippocampus varied by genotype, and compared with prenatal maternal mental health and socioeconomic status. Gene × Environment models outcompeted models containing genotype or environment only to best explain the majority of measures but some, especially of the amygdaloid microstructure, were best explained by genotype only. Models including DNA methylation measured in the neonate umbilical cords outcompeted the Gene and Gene × Environment models for the majority of amygdaloid measures and minority of hippocampal measures. This study identified brain region-specific gene networks associated with individual differences in fetal brain development. In particular, genetic and epigenetic variation within CUX1 was highlighted.

Neural response to stress and perceived stress differ in patients with left temporal lobe epilepsy

Patients with epilepsy are often able to predict seizure occurrence subsequent to an acute stress experience. However, neuroimaging investigations into the neural basis of this relationship or the potential influence of perceived life stress are limited. The current study assessed the relationship between perceived stress and the neurobehavioral response to stress in patients with left temporal lobe epilepsy (LTLE) and healthy controls (HCs) using heart rate, salivary cortisol level, and functional magnetic resonance imaging and compared these effects between HCs and LTLE. Matched on perceived stress levels, groups of 36 patients with LTLE and 36 HCs completed the Montreal Imaging Stress Task, with control and stress math task conditions. Among LTLEs, 27 reported that prior (acute) stress affected their seizures (LTLES+), while nine did not (LTLES-). The results revealed that increased perceived stress was associated with seizure frequency in LTLE. Further, cortisol secretion was greater in LTLE, but did not vary with perceived stress as observed in HCs. A linear mixed-effects analysis revealed that as perceived stress increased, activation in the hippocampal complex (parahippocampal gyrus and hippocampus) decreased during stressful math in the LTLES+, increased in HCs, but did not vary in the LTLES-. Task-based functional connectivity analyses revealed LTLE differences in hippocampal functional connectivity with sensory cortex specific to stressor modalities. We argue that the current study demonstrates an inhibitory hippocampal mechanism underlying differences in resilience to stress between HCs and LTLE, as well as LTLE patients who report stress as a precipitant of seizures.

Amygdala and prefrontal cortex activity varies with individual differences in the emotional response to psychosocial stress

Stress elicits a variety of psychophysiological responses that show large interindividual variability. Determining the neural mechanisms that mediate individual differences in the emotional response to stress would provide new insight that would have important implications for understanding stress-related disorders. Therefore, the present study examined individual differences in the relationship between brain activity and the emotional response to stress. In the largest stress study to date, 239 participants completed the Montreal Imaging Stress Task (MIST) while heart rate, skin conductance response (SCR), cortisol, self-reported stress, and blood oxygen level dependent (BOLD) functional MRI (fMRI) signal responses were measured. The relationship between differential responses (heart rate, SCR, cortisol, and self-reported stress) and differential BOLD fMRI data was analyzed. Dorsolateral prefrontal cortex (PFC), dorsomedial PFC, ventromedial PFC, and amygdala activity varied with the behavioral response (i.e., SCR and self-reported stress). These results suggest the PFC and amygdala support processes that are important for the expression and regulation of the emotional response to stress, and that stress-related PFC and amygdala activity underlie interindividual variability in peripheral physiologic measures of the stress response. (PsycINFO Database Record (c) 2019 APA, all rights reserved).