Acute stress and human spatial working memory strategy use.

Acute stress can impair human working memory. Little is known, however, about the effects of acute stress on working memory strategies. The goal of this research was to investigate the effects of acute stress on use of a systematic spatial working memory search strategy. Participants (28 females and 20 males per group) completed the Trier Social Stress Test (TSST) or control tasks. Use of a systematic spatial working memory search strategy was measured through performance on the spatial working memory subtest of the Cambridge Neuropsychological Test Automated Battery (CANTAB). The TSST was effective at producing subjective and cortisol stress responses, but there was no significant stress effect on use of a systematic search strategy or working memory search errors. There were also no significant relationships between subjective and cortisol stress responses and use of a systematic search strategy or working memory search errors within the stress group. These results suggest that acute stress does not impair the self-generation or execution of a systematic spatial working memory search strategy.

Subjective stress and proactive and reactive cognitive control strategies.

Acute stress likely impacts cognitive control. Little is known, however, about the effects that acute stress may have on specific cognitive control strategies. The goal of this research was to investigate the effects of acute stress on proactive and reactive control strategies. Participants completed the Trier Social Stress Test or control tasks. Use of proactive and reactive control strategies was measured with the AX-Continuous Performance Test. The Trier Social Stress Test was effective at producing subjective, cortisol, and heart rate stress responses, but there was no significant effect of stress on use of proactive or reactive control strategies in between-group analyses. However, higher subjective stress responses during performance of the AX-Continuous Performance Test were associated with less frequent use of a proactive control strategy and more frequent use of a reactive control strategy within the stress group.

Bilateral amygdala damage linked to impaired ability to predict others' fear but preserved moral judgements about causing others fear.

The amygdala is a subcortical structure implicated in both the expression of conditioned fear and social fear recognition. Social fear recognition deficits following amygdala lesions are often interpreted as reflecting perceptual deficits, or the amygdala's role in coordinating responses to threats. But these explanations fail to capture why amygdala lesions impair both physiological and behavioural responses to multimodal fear cues and the ability to identify them. We hypothesized that social fear recognition deficits following amygdala damage reflect impaired conceptual understanding of fear. Supporting this prediction, we found specific impairments in the ability to predict others' fear (but not other emotions) from written scenarios following bilateral amygdala lesions. This finding is consistent with the suggestion that social fear recognition, much like social recognition of states like pain, relies on shared internal representations. Preserved judgements about the permissibility of causing others fear confirms suggestions that social emotion recognition and morality are dissociable.

Diffusion tensor imaging findings and neuropsychological performance in adults with TBI across the spectrum of severity in the chronic-phase.

PRIMARY OBJECTIVE: To examine associations between neuroimaging indicators of cerebral tract integrity and neurocognitive functioning in traumatic brain injury (TBI). RESEARCH DESIGN: Between-Groups design with two TBI groups and controls. METHOD AND PROCEDURES: Forty-four participants with TBI and 27 matched controls completed diffusion tensor imaging and neuropsychological measures of processing speed, attention, memory, and executive function. Multivariate analyses were conducted to examine group differences in white matter integrity (fractional anisotropy) for 11 regions of interest and cognitive performance among adult males with chronic phase, mild, moderate, or severe TBI. Correlational analyses investigated associations between white matter integrity, brain injury severity, and cognitive status. MAIN OUTCOMES AND RESULTS: Participants with moderate or severe TBI exhibited reduced white matter integrity in 8 of 11 ROIs and worse performance on most cognitive measures, relative to control participants. Persons with mild TBI did not differ from controls on white matter integrity values and differed on one measure of processing speed. Significant correlations were found between injury severity ratings and 10 ROIs, most notably between ROIs and measures of processing speed or memory. CONCLUSIONS: These findings provide nuanced information regarding white matter connectivity as it relates to neurocognitive abilities across the TBI severity spectrum.

In sickness and in health: partner's physical and mental health predicts cortisol levels in couples.

Individuals in stable relationships tend to be healthier than those not in stable relationships. Despite this general positive influence of relationships on health, the mechanisms for the impact of relationship quality on health are not clear. Research has focused on many factors to explain this connection, including inter- and intra-couple dynamics of physiology and behavior. To address this issue, we examined the relationship between perceived health, depressive symptoms, and relationship quality on diurnal cortisol in 30 male/female romantic dyads (N = 60). Participants provided saliva samples on two weekdays to assess total cortisol output. Females' lower perceived physical health, lower relationship satisfaction, and higher depression scores were each related to higher cortisol output in their male partners. Males' physical health, relationship satisfaction, and depression scores were unrelated to females' cortisol output. Further, physical health, relationship satisfaction, and depression scores did not predict intra-individual cortisol levels for either sex. Measures of diurnal cortisol slope (DCS) were unrelated to psychosocial factors in males and females. Results provide further support for the interpersonal influence of partners' mental and physical health on physiological outcomes and suggest females may influence their male partners more than vice versa.

Only "efficient" emotional stimuli affect the content of working memory during free-recollection from natural scenes.

Emotional events are thought to have privileged access to attention and memory, consuming resources needed to encode competing emotionally neutral stimuli. However, it is not clear whether this detrimental effect is automatic or depends on the successful maintenance of the specific emotional object within working memory. Here, participants viewed everyday scenes including an emotional object among other neutral objects followed by a free-recollection task. Results showed that emotional objects-irrespective of their perceptual saliency-were recollected more often than neutral objects. The probability of being recollected increased as a function of the arousal of the emotional objects, specifically for negative objects. Successful recollection of emotional objects (positive or negative) from a scene reduced the overall number of recollected neutral objects from the same scene. This indicates that only emotional stimuli that are efficient in grabbing (and then consuming) available attentional resources play a crucial role during the encoding of competing information, with a subsequent bias in the recollection of neutral representations.

Tip of the Tongue States Increase Under Evaluative Observation.

We tested the frequent assumption that the difficulty of word retrieval increases when a speaker is being observed and evaluated. We modified the Trier Social Stress Test (TSST) so that participants believed that its evaluative observation components continued throughout the duration of a subsequent word retrieval task, and measured participants' reported tip of the tongue (TOT) states. Participants in this TSST condition experienced more TOTs than participants in a comparable, placebo TSST condition in which there was no suggestion of evaluative observation. This experiment provides initial evidence confirming the assumption that evaluative observation by a third party can be disruptive to word retrieval. We interpret our findings by proposing an extension to a well-supported theoretical model of TOTs.

Individual differences in cognitive control processes and their relationship to emotion regulation.

Cognitive control and emotional control share many similarities, but the specific relationship between these processes is not well understood. This study explored the relationship between three types of cognitive control (working memory updating, response inhibition and set-shifting) and two emotional regulation strategies (expressive suppression and cognitive reappraisal). Corrugator electromyography, behaviour and self-reports of affect were measured as indices of emotion regulation. Results indicate that working memory updating predicted negative affect reduction during reappraisal and during expressive suppression. This study specifically shows that the working memory component of cognitive control is associated with negative affect reduction. Response inhibition and set-shifting were not specifically related to negative affect reduction, but these variables did predict aspects of emotional behaviour and regulation. These results suggest a general role for cognitive control in some aspects of emotion regulation as well as a specific modulatory role for working memory updating in the regulation of negative affect.

Cortisol awakening response predicts intrinsic functional connectivity of the medial prefrontal cortex in the afternoon of the same day.

Cortisol awakening response (CAR) is the cortisol secretory activity in the first 30-60 min immediately after awakening in the morning. Alterations in CAR as a trait have been associated with changes in the brain structure and function. CAR also fluctuates over days. Little, however, is known about the relationship between CAR as a state and brain activity. Using resting-state functional magnetic resonance imaging (fMRI), we investigated whether the CAR predicts intrinsic functional connectivity (FC) of the brain in the afternoon of the same day. Data from forty-nine healthy participants were analyzed. Salivary cortisol levels were assessed immediately after awakening and 15, 30 and 60 min after awakening, and resting-state fMRI data were obtained in the afternoon. Global FC strength (FCS) of each voxel was computed to provide a whole-brain characterization of intrinsic functional architecture. Correlation analysis was used to examine whether CAR predicts the intrinsic FC of core brain networks. We observed that the CAR was positively correlated with the FCS of the medial prefrontal cortex (mPFC). Further analysis revealed that higher CAR predicted stronger positive mPFC connectivity with regions in the default mode network. Our findings suggest that the HPA activity after awakening in the early morning may predict intrinsic functional connectivity of mPFC at rest in the afternoon of the same day.

High cortisol awakening response is associated with impaired error monitoring and decreased post-error adjustment.

The cortisol awakening response (CAR), a rapid increase in cortisol levels following morning awakening, is an important aspect of hypothalamic-pituitary-adrenocortical axis activity. Alterations in the CAR have been linked to a variety of mental disorders and cognitive function. However, little is known regarding the relationship between the CAR and error processing, a phenomenon that is vital for cognitive control and behavioral adaptation. Using high-temporal resolution measures of event-related potentials (ERPs) combined with behavioral assessment of error processing, we investigated whether and how the CAR is associated with two key components of error processing: error detection and subsequent behavioral adjustment. Sixty university students performed a Go/No-go task while their ERPs were recorded. Saliva samples were collected at 0, 15, 30 and 60 min after awakening on the two consecutive days following ERP data collection. The results showed that a higher CAR was associated with slowed latency of the error-related negativity (ERN) and a higher post-error miss rate. The CAR was not associated with other behavioral measures such as the false alarm rate and the post-correct miss rate. These findings suggest that high CAR is a biological factor linked to impairments of multiple steps of error processing in healthy populations, specifically, the automatic detection of error and post-error behavioral adjustment. A common underlying neural mechanism of physiological and cognitive control may be crucial for engaging in both CAR and error processing.

Chronic stress exposure decreases the cortisol awakening response in healthy young men.

Academic examination is a major stressor for students in China. Investigation of stress-sensitive endocrine responses to major examination stress serves as a good model of naturalistic chronic psychological stress in an otherwise healthy population. The cortisol awakening response (CAR) is an endocrine marker of the hypothalamic-pituitary-adrenocortical (HPA) axis in response to stress. However, it remains unknown how chronic examination stress impacts the CAR in a young healthy population To exclude the influence of sex effects on hormone level, the CAR and psychological stress responses were assessed on two consecutive workdays in 42 male participants during their preparations for the Chinese National Postgraduate Entrance Exam (NPEE) and 21 non-exam, age-matched male comparisons. On each day, four saliva samples were collected immediately after awakening, 15 minutes, 30 minutes and 60 minutes after awakening. The waking level (S1), the increase within 30 minutes after awakening (R30), the area under the curve with respect to ground (AUCg), and the area under the curve with respect to increase (AUCi) were used to quantify the CAR. Psychological stress and anxiety were assessed by the Perceived Stress Scale and the Spielberger State-Trait Anxiety Inventory, respectively. Male participants in the exam group had greater perceived stress and anxiety scores relatibe to the non-exam group. Both R30 and AUCi in the exam group were significantly lower than the comparison group and this effect was most pronounced for participants with high levels of perceived stress in the exam group. Perceived stress and anxiety levels were negatively correlated with both R30 and AUCi. Chronic examination stress can lead to the decrease of CAR in healthy young men, possibly due to reduced HPA axis activity under long-term sustained stress.

A mechanism for impaired fear recognition after amygdala damage.

Ten years ago, we reported that SM, a patient with rare bilateral amygdala damage, showed an intriguing impairment in her ability to recognize fear from facial expressions. Since then, the importance of the amygdala in processing information about facial emotions has been borne out by a number of lesion and functional imaging studies. Yet the mechanism by which amygdala damage compromises fear recognition has not been identified. Returning to patient SM, we now show that her impairment stems from an inability to make normal use of information from the eye region of faces when judging emotions, a defect we trace to a lack of spontaneous fixations on the eyes during free viewing of faces. Although SM fails to look normally at the eye region in all facial expressions, her selective impairment in recognizing fear is explained by the fact that the eyes are the most important feature for identifying this emotion. Notably, SM's recognition of fearful faces became entirely normal when she was instructed explicitly to look at the eyes. This finding provides a mechanism to explain the amygdala's role in fear recognition, and points to new approaches for the possible rehabilitation of patients with defective emotion perception.

Cumulative lifetime stress exposure predicts greater impulsivity and addictive behaviors.

The study investigated whether lifetime stress exposure is associated with greater impulsivity and addictive behavior. We also examined whether stress and impulsivity interactively predicted food addiction and alcohol-related behavior. Greater lifetime stress exposure was related to more impulsivity and food addictive behaviors, but not alcohol-related consequences. There were no interactions between lifetime stress exposure and impulsivity in predicting addictive behaviors. Exploratory analyses revealed that early and adulthood stress exposure predicted food addiction, whereas only adulthood stress predicted alcohol-related consequences. Therefore, lifetime stress exposure is related to impulsivity and addiction, but these effects differ by addiction outcome and specific timing of stress exposure.

Predictive neural coding of reward preference involves dissociable responses in human ventral midbrain and ventral striatum.

Food preferences are acquired through experience and can exert strong influence on choice behavior. In order to choose which food to consume, it is necessary to maintain a predictive representation of the subjective value of the associated food stimulus. Here, we explore the neural mechanisms by which such predictive representations are learned through classical conditioning. Human subjects were scanned using fMRI while learning associations between arbitrary visual stimuli and subsequent delivery of one of five different food flavors. Using a temporal difference algorithm to model learning, we found predictive responses in the ventral midbrain and a part of ventral striatum (ventral putamen) that were related directly to subjects' actual behavioral preferences. These brain structures demonstrated divergent response profiles, with the ventral midbrain showing a linear response profile with preference, and the ventral striatum a bivalent response. These results provide insight into the neural mechanisms underlying human preference behavior.

How Do Stress and Social Closeness Impact Prosocial Behavior?

Factors such as time pressure and psychosocial stress may increase or decrease prosocial behavior depending on a number of factors. One factor that consistently positively impacts prosocial behavior is relationship status: Prosocial behavior is more likely toward kin than toward strangers. The interactions among stress, kin relationships, and prosocial behavior were examined in two separate experiments. In Study 1, 79 university students were asked to decide how much money to donate to family members, friends, or strangers, either under time pressure or with no time constraints. Participants donated more to close kin and friends than to strangers, but time pressure did not increase prosocial behavior. In Study 2, 94 university students completed the Trier Social Stress Test for Groups (TSST-G) or a control task, followed by a similar donation task as used in Study 1. Participants donated more to close kin and friends than to strangers, but stress did not influence donation amounts. These results do not support the hypothesis that stress due to time pressure or psychosocial factors increases prosocial behavior.

Diurnal cortisol and decision making under risk in problem gambling.

The aim of this study was to assess the influence of diurnal cortisol profile on decision making under risk in individuals with problem gambling and a healthy control group. We examined the relationship between diurnal cortisol, assessed over the course of 2 days, and a battery of tasks that assessed decision making under risk, including the Columbia Card Task and the Cups Task. Thirty individuals with problem gambling and 29 healthy individuals took part in the study. Those with problem gambling showed blunted diurnal cortisol and more risk taking behavior compared with those in the healthy control group. Blunted cortisol profile was associated with more risky behavior and less sensitivity to losing money in problem gambling. These findings suggest that blunted stress physiology plays a role in specific parameters of risky decision making in problem gambling. (PsycINFO Database Record (c) 2020 APA, all rights reserved).

Hippocampal damage abolishes the cortisol response to psychosocial stress in humans.

The hippocampus (HC) is necessary for learning and memory, but it also plays a role in other behaviors such as those related to stress and anxiety. In support of the latter idea, we show here that bilateral HC damage abolishes the cortisol response to psychosocial stress. We collected salivary cortisol, heart rate, and affective responses to the Trier Social Stress Test (TSST) from 7 participants with bilateral HC lesions, 12 participants with damage outside the HC, and 28 healthy normal comparison participants matched to the HC participants on age and sex. HC participants showed elevated pre-stress cortisol, but no cortisol response to the TSST. Heart rate and affective responses in the HC group were similar to those of the comparison groups. Participants with brain damage outside the HC showed stress responses that were comparable to those of the healthy comparison group. These findings support the idea that the functions of the human HC extend beyond learning and memory, and suggest that the HC is necessary for producing the cortisol response to psychosocial stress.

Amygdala damage impairs emotional memory for gist but not details of complex stimuli.

Neurobiological studies demonstrate the amygdala's role in emotional memory, and psychological studies suggest a particular pattern: enhanced memory for the gist but not the details of complex stimuli. We hypothesized that these two findings are related. Whereas normal (n = 52) and brain-damaged (n = 22) controls showed the expected enhancement of gist memory when the encoding context was emotional, persons with unilateral damage to the medial temporal lobe including the amygdala (n = 16) did not show this pattern. Furthermore, amygdala volume showed a significant positive correlation with gist memory but not with overall memory. A further study in four subjects with selective medial temporal damage sparing the amygdala, and one with selective damage confined to the amygdala, confirmed the specificity of this effect to the amygdala. The data support a model whereby the amygdala focuses processing resources on gist, possibly accounting for features of traumatic memories and eyewitness testimony in real life.

The role of genetics in stress effects on health and addiction.

Advances in stress research have yielded new insights into how stress exposure, in combination with genetics, can contribute to poor health outcomes. We review these topics with a special emphasis on early life stress and vulnerability to addiction. The direct effects of stress and our compensatory responses can modify our physiology and behavior during future stress episodes. These consequences can influence health, including an increased propensity for addiction. The relation between stress and health is not uniform across individuals. Some people succumb to stress-related disorders while others are resilient. Specific genetic polymorphisms affect how an individual appraises and responds to stress, potentially mediating the impact of stress on health. These genetic vulnerabilities can influence responses to the external environment, shape motivated behavior, and have an impact on health throughout life.

Diurnal Cortisol Dynamics, Perceived Stress, and Language Production in Aphasia.

Purpose The current study investigated diurnal cortisol dynamics in adults with and without aphasia, along with subjective reports of stress and measures of language production. Dysregulation of cortisol, a common biomarker of stress, is associated with cognitive dysfunction in different clinical populations. However, little is known about the consequences of stress-induced cortisol disturbances for stroke survivors, including those with aphasia. Method Nineteen participants with aphasia and 14 age-matched neurotypical adults were tested. Saliva samples were collected from participants to assess the cortisol awakening response, a marker of the integrity of the hypothalamic-pituitary-adrenal (HPA) axis. Participants also completed 2 subjective stress questionnaires. Language was evaluated using 3 short, picture description narratives, analyzed for discourse (dys)fluency and productivity markers. Results In contrast to neurotypical participants, adults with aphasia did not show the predictable cortisol awakening response. Participants with aphasia also showed an unusual heightened level of cortisol upon awakening. Additionally, neurotypical participants demonstrated an association between intact language performance and the cortisol awakening response, whereas the participants with aphasia did not, although they did perceive the language tasks as stressful. Conclusion This study indicates that the functionality of the HPA axis, as indexed by cortisol, contributes to optimal language performance in healthy adults. The absence of an awakening response among participants with aphasia suggests that stroke leads to dysregulation of the HPA axis, although the degree to which this impairment affects language deficits in this population requires further investigation.