A large body of research has demonstrated that affective disorders are characterized by attentional biases for emotional stimuli. However, this research relies heavily on manual reaction time (RT) measures that cannot fully delineate the time course and components of attentional bias. Eye tracking technology, which allows relatively direct and continuous measurement of overt visual attention, may provide an important supplement to RT measures. This article reviews eye tracking research on anxiety and depression, evaluating the experimental paradigms and eye movement indicators used to study attentional biases. Also included is a meta-analysis of extant eye tracking research (33 experiments; N=1579) on both anxiety and depression. Relative to controls, anxious individuals showed increased vigilance for threat during free viewing and visual search, and showed difficulty disengaging from threat in visual search tasks, but not during free viewing. In contrast, depressed individuals were not characterized by vigilance for threat during free viewing, but were characterized by reduced orienting to positive stimuli, as well as reduced maintenance of gaze on positive stimuli and increased maintenance of gaze on dysphoric stimuli. Implications of these findings for theoretical accounts of attentional bias in anxiety and depression are discussed, and avenues for future research using eye-tracking technology are outlined. (C) 2012 Elsevier Ltd.

The prefrontal cortex (PFC) - the most evolved brain region - subserves our highest-order cognitive abilities. However, it is also the brain region that is most sensitive to the detrimental effects of stress exposure. Even quite mild acute uncontrollable stress can cause a rapid and dramatic loss of prefrontal cognitive abilities, and more prolonged stress exposure causes architectural changes in prefrontal dendrites. Recent research has begun to reveal the intracellular signalling pathways that mediate the effects of stress on the PFC. This research has provided clues as to why genetic or environmental insults that disinhibit stress signalling pathways can lead to symptoms of profound prefrontal cortical dysfunction in mental illness.

In designing an ERP study, researchers must choose how many trials to include, balancing the desire to maximize statistical power and the need to minimize the length of the recording session. Recent studies have attempted to quantify the minimum number of trials needed to obtain reliable measures for a variety of ERP components. However, these studies have largely ignored other variables that affect statistical power in ERP studies, including sample size and effect magnitude. The goal of the present study was to determine whether and how the number of trials, number of participants, and effect magnitude interact to influence statistical power, thus providing a better guide for selecting an appropriate number of trials. We used a Monte Carlo approach to measure the probability of obtaining a statistically significant result when testing for (a) the presence of an ERP effect, (b) within-participant condition differences in an ERP effect, and (c) between-participants group differences in an ERP effect. Each of these issues was examined in the context of the error-related negativity and the lateralized readiness potential. We found that doubling the number of trials recommended by previous studies led to more than a doubling of statistical power under many conditions. Thus, when determining the number of trials that should be included in a given study, researchers must consider the sample size, the anticipated effect magnitude, and the noise level, rather than relying solely on general recommendations about the number of trials needed to obtain a "stable" ERP waveform.

An important aspect of the fear response is the allocation of spatial attention toward threatening stimuli. This response is so powerful that modulations in spatial attention can occur automatically without conscious awareness. Functional neuroimaging research suggests that the amygdala and anterior cingulate cortex (ACC) form a network involved in the rapid orienting of attention to threat. A hyper-responsive attention bias to threat is a common component of anxiety disorders. Yet, little is known of how individual differences in underlying brain morphometry relate to variability in attention bias to threat. Here, we performed two experiments using dot-probe tasks that measured individuals' attention bias to backward masked fearful faces. We collected whole-brain structural magnetic resonance images and used voxel-based morphometry to measure brain morphometry. We tested the hypothesis that reduced gray matter within the amygdala and ACC would be associated with reduced attention bias to threat. In Experiment 1, we found that backward masked fearful faces captured spatial attention and that elevated attention bias to masked threat was associated with greater ACC gray matter volumes. In Experiment 2, this association was replicated in a separate sample. Thus, we provide initial and replicating evidence that ACC gray matter volume is correlated with biased attention to threat. Importantly, we demonstrate that variability in affective attention bias within the healthy population is associated with ACC morphometry. This result opens the door for future research into the underlying brain morphometry associated with attention bias in clinically anxious populations. (C) 2011 Elsevier Inc.

Dot probe studies indicate that masked fearful faces modulate spatial attention. However, without a baseline to compare congruent and incongruent reaction times, it is unclear which aspect(s) of attention (orienting or disengagement) is affected. Additionally, backward masking studies commonly use a neutral face as the mask stimulus. This method results in greater perceptual inconsistencies for fearful as opposed to neutral faces. Therefore, it is currently unclear whether the effects of backward masked fearful faces are due to the fearful nature of the face or perceptual inconsistencies. Equally unclear, is whether this spatial attention effect is due to orienting or disengagement. Two modified dot probe experiments with neutral (closed mouth in Experiment 1) and smiling (open mouth in Experiment 2) masks were used to determine the role of perceptual inconsistencies in mediating the spatial attention effects elicited by masked fearful faces. The results indicate that masked fearful faces modulate the orienting of spatial attention, and it appears that this effect is due to the fearful nature of the face rather than perceptual inconsistencies between the initial faces and masks.

AbstractA wealth of research demonstrates attentional biases toward threat in the anxiety disorders. Several models have been advanced to explain these biases in anxiety, yet the mechanisms comprising and mediating the biases remain unclear. In the present article, we review evidence regarding the mechanisms of attentional biases through careful examination of the components of attentional bias, the mechanisms underlying these components, and the stage of information processing during which the biases occur. Facilitated attention, difficulty in disengagement, and attentional avoidance comprise the components of attentional bias. A threat detection mechanism likely underlies facilitated attention, a process that may be neurally centered around the amygdala. Attentional control ability likely underlies difficulty in disengagement, emotion regulation goals likely underlie attentional avoidance, and both of these processes may be neurally centered around prefrontal cortex functioning. The threat detection mechanism may be a mostly automatic process, attentional avoidance may be a mostly strategic process, and difficulty in disengagement may be a mixture of automatic and strategic processing. Recommendations for future research are discussed.]]>

AbstractA number of studies using the dot-probe task now report the existence of an attentional bias to angry faces in participants who rate highly on scales of anxiety; however, no equivalent bias has been observed in non-anxious populations, despite evidence to the contrary from studies using other tasks. One reason for this discrepancy may be that researchers using the dot-probe task have rarely investigated any effects which might emerge earlier than 500 ms following presentation of the threat-related faces. Accordingly, in the current study we presented pairs of face stimuli with emotional and neutral expressions and probed the allocation of attention to these stimuli for presentation times of 100 and 500 ms. Results showed that at 100 ms there was an attentional bias towards the location of the relatively threatening stimulus (the angry face in angry/neutral pairs and the neutral face in neutral/happy pairs) and this pattern reversed by 500 ms. Comparisons of reaction time (RT) scores with an appropriate baseline suggested that the early bias toward threatening faces may actually arise through inhibition of the relatively least threatening member of a face pair rather than through facilitation of, or vigilance towards, the more threatening stimulus. However the mechanisms governing the observed biases are interpreted, these data provide evidence that probing for the location of spatial attention at 500 ms is not necessarily indicative of the initial allocation of attention between competing emotional facial stimuli.]]>

Probing gene-environment interactions that affect neural processing is crucial for understanding individual differences in behavior and disease vulnerability. Here, we tested whether the current environmental context, which affects the acute brain state, modulates genotype effects on brain function in humans. We manipulated the context by inducing acute psychological stress, which increases noradrenergic activity, and probed its effect on tonic activity and phasic responses in the amygdala using two MRI techniques: conventional blood oxygen level-dependent functional MRI and arterial spin labeling. We showed that only carriers of a common functional deletion in ADRA2B, the gene coding for the alpha2b-adrenoreceptor, displayed increased phasic amygdala responses under stress. Tonic activity, reflecting the perfusion of the amygdala, increased independently of genotype after stress induction. Thus, when tonic activity was heightened by stress, only deletion carriers showed increased amygdala responses. Our results demonstrate that genetic effects on brain operations can be state dependent, such that they only become apparent under specific, often environmentally controlled, conditions.

Intrusive memories resulting from an emotional trauma are a defining feature of posttraumatic stress disorder (PTSD). Existing studies demonstrate that an increase of noradrenergic activity during a life-threatening event contributes to strengthening or "overconsolidation" of the memory for trauma. The lateral nucleus of the amygdala (LA) is critical for fear learning. Using classical fear conditioning in rats, we have recently demonstrated that noradrenergic blockade in the LA following reactivation of fear memory by retrieval disrupts memory reconsolidation and lastingly impairs fear memory. This suggests that noradrenergic blockade may be useful in attenuating traumatic memories, even well-consolidated old memories, in PTSD.

In response to stress, the brain activates several neuropeptide-secreting systems. This eventually leads to the release of adrenal corticosteroid hormones, which subsequently feed back on the brain and bind to two types of nuclear receptor that act as transcriptional regulators. By targeting many genes, corticosteroids function in a binary fashion, and serve as a master switch in the control of neuronal and network responses that underlie behavioural adaptation. In genetically predisposed individuals, an imbalance in this binary control mechanism can introduce a bias towards stress-related brain disease after adverse experiences. New candidate susceptibility genes that serve as markers for the prediction of vulnerable phenotypes are now being identified.

The salience map is a crucial concept for many theories of visual attention. On this map, each object in the scene competes for selection - the more conspicuous the object, the greater its representation, and the more likely it will be chosen. In recent years, the firing patterns of single neurons have been interpreted using this framework. Here, we review evidence showing that the expression of salience is remarkably similar across structures, remarkably different across tasks, and modified in important ways when the salient object is consistent with the goals of the participant. These observations have important ramifications for theories of attention. We conclude that priority--the combined representation of salience and relevance--best describes the firing properties of neurons.

In rodents, cyclically fluctuating levels of gonadal steroid hormones modulate neural plasticity by altering synaptic transmission and synaptogenesis. Alterations of mood and cognition observed during the menstrual cycle suggest that steroid-related plasticity also occurs in humans. Cycle phase-dependent differences in cognitive performance have almost exclusively been found in tasks probing lateralized neuronal domains, i.e., cognitive domains such as language, which are predominantly executed by one hemisphere. To search for neural correlates of hormonally mediated neural plasticity in humans, we thus conducted a functional magnetic resonance imaging study measuring brain activity related to a semantic decision task in the language domain. This was contrasted with a letter-matching task in the perceptual domain, in which we expected no steroid hormone-mediated effect. We investigated 12 young healthy women in a counterbalanced repeated-measure design during low-steroid menstruation and high-steroid midluteal phase. Steroid serum levels correlated with the volume and lateralization of particular brain activations related to the semantic task but not with brain activity related to the perceptual task. More specifically, bilateral superior temporal recruitment correlated positively with progesterone and medial superior frontal recruitment with both progesterone and estradiol serum levels, whereas activations in inferior and middle frontal cortex were unaffected by steroid levels. In contrast to these specific interactions, testosterone levels correlated nonselectively with overall activation levels by neural and/or vascular factor(s). In conclusion, our data demonstrate steroid hormone responsivity in the adult human brain by revealing neural plasticity in the language domain, which appears hormone, task, and region specific.

Biases in information processing undoubtedly play an important role in the maintenance of emotion and emotional disorders. In an attentional cueing paradigm, threat words and angry faces had no advantage over positive or neutral words (or faces) in attracting attention to their own location, even for people who were highly state-anxious. In contrast, the presence of threatening cues (words and faces) had a strong impact on the disengagement of attention. When a threat cue was presented and a target subsequently presented in another location, high state-anxious individuals took longer to detect the target relative to when either a positive or a neutral cue was presented. It is concluded that threat-related stimuli affect attentional dwell time and the disengage component of attention, leaving the question of whether threat stimuli affect the shift component of attention open to debate.

SIGNIFICANCE STATEMENT The human tendency to be overly optimistic has mystified scholars and lay people for decades: How could biased beliefs have been selected over unbiased beliefs? Scholars have suggested that although the optimism bias can lead to negative outcomes, including financial collapse and war, it can also facilitate health and productivity. Here, we demonstrate that a mechanism generating the optimism bias, namely asymmetric information integration, evaporates under threat. Such flexibility could result in enhanced caution in dangerous environments while supporting an optimism bias otherwise, potentially increasing well-being.]]>

D) component, a putative neural index of suppression. Other support comes from a handful of behavioral studies showing that processing at the salient locations is inhibited compared with other locations. The current study was designed to link the behavioral and neural evidence by combining ERP recordings with an experimental paradigm that provides a behavioral measure of suppression. We found that, when a salient distractor item elicited the PD component, processing at the location of this distractor was suppressed below baseline levels. Furthermore, the magnitude of behavioral suppression and the magnitude of the PD component covaried across participants. These findings provide a crucial connection between the behavioral and neural measures of suppression, which opens the door to using the PD component to assess the timing and neural substrates of the behaviorally observed suppression.]]>

Recent studies have demonstrated that black patients receive substandard care compared with white patients across healthcare settings. The purpose of this study was to evaluate the association of race on the management (salvage vs. amputation) of traumatic lower extremity open fractures.

binds visuospatial, motor, and cognitive information into a topographically organized signal of behavioral salience. By specifying attentional priority as a synthesis of multiple task demands, LIP operates at the interface of perception, action, and cognition.]]>

Overgeneralization of fear to safety cues is increasingly being studied in order to further our understanding of the maintenance of anxiety disorders. The current study used event-related potentials (ERPs) to evaluate whether worry affects anticipation and processing of threat and neutral pictures during a conditioning task. Fifty-two high (n=24) and low (n=28) worriers completed a paradigm in which a neutral stimulus indicated the valence of a second stimulus, either a threat or neutral picture. Results found that worriers displayed reduced anticipatory responses to both stimulus types as indexed by the stimulus preceding negativity, although they displayed an increased stimulus preceding negativity to threatening images during the second half of the task. In addition, high and low worriers differed in processing of threat and neutral images as indexed by the late positive potential. These findings support the overgeneralization of fear literature, suggesting that worriers display difficulty discriminating safety cues from threat cues, and this affects the attentional resources devoted to subsequent stimuli. Implications of these results are discussed.

Stress initiates an intricate response that affects diverse cognitive and affective domains, with the goal of improving survival chances in the light of changing environmental challenges. Here, we bridge animal data at cellular and systems levels with human work on brain-wide networks to propose a framework describing how stress-related neuromodulators trigger dynamic shifts in network balance, enabling an organism to comprehensively reallocate its neural resources according to cognitive demands. We argue that exposure to acute stress prompts a reallocation of resources to a salience network, promoting fear and vigilance, at the cost of an executive control network. After stress subsides, resource allocation to these two networks reverses, which normalizes emotional reactivity and enhances higher-order cognitive processes important for long-term survival.

Acute stress shifts the brain into a state that fosters rapid defense mechanisms. Stress-related neuromodulators are thought to trigger this change by altering properties of large-scale neural populations throughout the brain. We investigated this brain-state shift in humans. During exposure to a fear-related acute stressor, responsiveness and interconnectivity within a network including cortical (frontoinsular, dorsal anterior cingulate, inferotemporal, and temporoparietal) and subcortical (amygdala, thalamus, hypothalamus, and midbrain) regions increased as a function of stress response magnitudes. beta-adrenergic receptor blockade, but not cortisol synthesis inhibition, diminished this increase. Thus, our findings reveal that noradrenergic activation during acute stress results in prolonged coupling within a distributed network that integrates information exchange between regions involved in autonomic-neuroendocrine control and vigilant attentional reorienting.

This study investigated the temporal course of attentional biases for threat-related (angry) and positive (happy) facial expressions. Electrophysiological (event-related potential) and behavioral (reaction time [RT]) data were recorded while participants viewed pairs of faces (e.g., angry face paired with neutral face) shown for 500 ms and followed by a probe. Behavioral results indicated that RTs were faster to probes replacing emotional versus neutral faces, consistent with an attentional bias for emotional information. Electrophysiological results revealed that attentional orienting to threatening faces emerged earlier (early N2pc time window; 180-250 ms) than orienting to positive faces (after 250 ms), and that attention was sustained toward emotional faces during the 250-500-ms time window (late N2pc and SPCN components). These findings are consistent with models of attention and emotion that posit rapid attentional prioritization of threat.

In this study, we investigated the time course of attentional bias for threat-related (angry) facial expressions under conditions of high versus low cognitive (working memory) load. Event-related potential (ERP) and reaction time (RT) data were recorded while participants viewed pairs of faces (angry paired with neutral face) displayed for 500 ms and followed by a probe. Participants were required to respond to the probe while performing a concurrent task of holding in working memory a sequence of digits that were either in the same order (low memory load) or in a random mixed order (high memory load). The ERP results revealed that higher working memory load resulted in enhanced lateralized neural responses to threatening relative to neutral faces, consistent with greater initial orienting of attention to threatening faces (early N2pc: 180-252 ms) and enhanced maintenance of processing representations of threat (late N2pc, 252-320 ms; SPCN, 320-500 ms). The ERP indices showed significant positive relationships with each other, and also with the behavioral index of attentional bias to threat (reflected by faster RTs to probes replacing angry than neutral faces at 500 ms), although the latter index was not significantly influenced by memory load. Overall, the findings indicate that depletion of cognitive control resources, using a working memory manipulation, increases the capacity of task-irrelevant threat cues to capture and hold attention.

The present study investigated the effect of acute stress on attentional bias to threat using behavioral and ERP methods. Sixty-two male participants were randomly assigned to a stress condition (Trier Social Stress Test) or a control condition. To examine the impact of stress-induced cortisol on attentional bias to threat, participants in the stress group were split into Low- and High cortisol responders. All participants were then administered a modified dot probe task in which the cues were neutral and angry faces. Behavioral results showed a pattern of attentional bias toward threat in the Control group but not in the stress group. For the ERPs, the P100 peaked earlier for the angry-cued targets than the neutral-cued targets in the Control group, which suggests a rapid, adaptive response toward threat. However, this effect was not observed in the stress group, suggesting a suppressed attentional bias under stress. In addition, the stress group (including both Low and High cortisol responders) showed reduced P300 amplitude to target onset than the Control group. These results suggest that acute stress disrupts attentional bias to threat including a reduction in early bias to threat in addition to a subsequent change of attention allocation.

The dot-probe task is often considered a gold standard in the field for investigating attentional bias to threat. However, serious issues with the task have been raised. Specifically, a number of studies have demonstrated that the traditional reaction time (RT) measure of attentional bias to threat in the dot-probe task has poor internal reliability and poor test-retest reliability. In addition, although threatening stimuli capture attention in other paradigms, attentional bias to threat has not usually been found in typical research participants in the dot-probe task. However, when attention is measured in the dot-probe task with the N2pc component of the event-related potential waveform, substantial attentional orienting to threat is observed, and the internal reliability is moderate. To provide a rigorous comparison of the reliability of this N2pc measure and the conventional behavioral measure, as well as to examine the relationship of these measures to anxiety, the present study examined the N2pc in conjunction with RT in the dot-probe task in a large sample of participants (N = 96). As in previous studies, RT showed no bias to threatening images across the sample and exhibited poor internal reliability. Moreover, this measure did not relate to trait anxiety. By contrast, the N2pc revealed a significant initial shift of attention to threat, and this measure was internally reliable. However, the N2pc was not correlated with trait anxiety, indicating that it does not provide a meaningful index of individual differences in anxiety in the dot-probe task. Together, these results indicate a serious need to develop new tasks and methods to more reliably investigate attentional bias to threat and its relationship to anxiety in both clinical and non-clinical populations.

Threatening stimuli have been shown to preferentially capture attention using a range of tasks and measures. However, attentional bias to threat has not typically been found in unselected individuals using behavioral measures in the dot-probe task, one of the most common ways of examining attention to threat. The present study leveraged event-related potentials (ERPs) in conjunction with behavioral measures in the dot-probe task to examine whether more direct measures of attention might reveal an attentional bias to threat in unselected individuals. As in previous dot-probe studies, we found no evidence of an attentional bias to threat using reaction time; additionally, this measure exhibited poor internal reliability. In contrast, ERPs revealed an initial shift of attention to threat-related stimuli, reflected by the N2pc, which showed moderate internal reliability. However, there was no evidence of sustained engagement with the threat-related stimuli, as measured by the late positive potential (LPP). Together, these results demonstrate that unselected individuals do initially allocate attention to threat in the dot-probe task, and further, that this bias is better characterized by neural measures of attention than traditional behavioral measures. These results have implications for the study of attention to threat in both unselected and anxious populations.

AbstractWith the steadily increasing number of publications in the field of stress research it has become evident that the conventional usage of the stress concept bears considerable problems. The use of the term ‘stress’ to conditions ranging from even the mildest challenging stimulation to severely aversive conditions, is in our view inappropriate. Review of the literature reveals that the physiological ‘stress’ response to appetitive, rewarding stimuli that are often not considered to be stressors can be as large as the response to negative stimuli. Analysis of the physiological response during exercise supports the view that the magnitude of the neuroendocrine response reflects the metabolic and physiological demands required for behavioural activity. We propose that the term ‘stress’ should be restricted to conditions where an environmental demand exceeds the natural regulatory capacity of an organism, in particular situations that include unpredictability and uncontrollability. Physiologically, stress seems to be characterized by either the absence of an anticipatory response (unpredictable) or a reduced recovery (uncontrollable) of the neuroendocrine reaction. The consequences of this restricted definition for stress research and the interpretation of results in terms of the adaptive and/or maladaptive nature of the response are discussed.Research highlights? The review evaluates the stress response during rewarding and aversive conditions. ? A stress response is characterized by a reduced recovery rather than its magnitude. ? The concepts of adaptive capacity and regulatory range are introduced. ? Implications for the use of the stress concept in stress research are discussed.]]>

AbstractThe dot probe task [J Abnorm Psychol 95 (1986) 15] is an often-used paradigm to investigate selective attention to threat. A facilitated response to probes that appear at the same location of threat information in comparison with responses to probes at the opposite location of threat information is interpreted as vigilance for threat. We argue that the findings in the dot probe paradigm are ambiguous evidence for the vigilance to threat hypothesis. Results can also be interpreted as a difficulty to disengage from threat. In this study, 44 undergraduates performed a pictorial version of the probe detection task. Taking into account the reaction times on neutral trials, we found no evidence for a facilitated detection of threatening information. It was found that the dot probe effects are at least partially due to disengagement effects. The implications of these results for the understanding of attentional bias in normal and anxious individuals are discussed.]]>

AbstractThere is a wealth of evidence demonstrating enhanced attention to threat in high trait anxious individuals (HTA) compared with low trait anxious individuals (LTA). In two experiments, we investigated whether this attentional bias is related to facilitated attentional engagement to threat or difficulties disengaging attention from threat. HTA and LTA undergraduates performed a modified exogenous cueing task, in which the location of a target was correctly or incorrectly cued by neutral, highly and mildly threatening pictures. Results indicate that at 100 ms picture presentation, HTA individuals more strongly engaged their attention with and showed impaired disengagement from highly threatening pictures than LTA individuals. In addition, HTA individuals showed a stronger tendency to attentional avoidance of threat at the 200 and 500 ms picture presentation. These data provide evidence for differential patterns of anxiety-related biases in attentive processing of threat at early versus later stages of information processing.]]>

When detecting a threat, humans and other animals engage in defensive behaviors and supporting physiological adjustments that vary with threat imminence and potential response options. In the present study, we shed light on the dynamics of defensive behaviors and associated physiological adjustments in humans using multiple psychophysiological and brain measures. When participants were exposed to a dynamically approaching, uncontrollable threat, attentive freezing was augmented, as indicated by an increase in skin conductance, fear bradycardia, and potentiation of the startle reflex. In contrast, when participants had the opportunity to actively avoid the approaching threat, attention switched to response preparation, as indicated by an inhibition of the startle magnitude and by a sharp drop of the probe-elicited P3 component of the evoked brain potentials. These new findings on the dynamics of defensive behaviors form an important intersection between animal and human research and have important implications for understanding fear and anxiety-related disorders.

Stress-related disorders, e.g., anxiety and depression, are characterized by decreased top-down control for distracting information, as well as a memory bias for threatening information. However, it is unclear how acute stress biases mnemonic encoding and leads to prioritized storage of threat-related information even if outside the focus of attention. In the current study, healthy adults (N = 53, all male) were randomly assigned to stress induction using the socially evaluated cold-pressor test (SECPT) or a control condition. Participants performed a task in which they were required to identify a target letter within a string of letters that were either identical to the target and thereby facilitating detection (low distractor load) or mixed with other letters to complicate the search (high load). Either a fearful or neutral face was presented on the background, outside the focus of attention. Twenty-four hours later, participants were asked to perform a surprise recognition memory test for those background faces. Stress induction resulted in increased cortisol and negative subjective mood ratings. Stress did not affect visual search performance, however, participants in the stress group showed stronger memory compared to the control group for fearful faces in the low attentional load condition. Critically, the stress induced memory bias was accompanied by decoupling between amygdala and DLFPC during encoding, which may represent a mechanism for decreased ability to filter task-irrelevant threatening background information. The current study provides a potential neural account for how stress can produce a negative memory bias for threatening information even if presented outside the focus of attention. Despite of an adaptive advantage for survival, such tendencies may ultimately also lead to generalized fear, a possibility requiring additional investigation.

Stress has profound impacts on physiology, the brain, cognition and behaviour. In response to stress, the brain initiates several neuromodulatory and endocrine systems. This leads to the release of stress-sensitive mediators, including neuromodulators, hormones and neuropeptides, which in turn feed back on the brain and thus alters cognition and behaviour. As the progress of sophisticated cognitive neuroimaging techniques, cognitive neuroscientists have begun to elucidate the psychological and neural mechanisms underlying detrimental and beneficial effects of stress on emotion, cognition and behaviour in the human brain. Stress-related neuromodulations occur at various stages of information processing, from the initial vigilance, attention, executive functions, learning and memory, and emotion. We reviewed recent advances in cognitive neuroscience of stress and proposed a multidimensional model of stress for better understanding how stress-sensitive neuromodulatory and endocrine systems interplay to impact the brain, cognition and behaviour in humans.

When facing strangers, one of the first evaluations people perform is to implicitly assess their trustworthiness. However, the underlying processes supporting trustworthiness appraisal are poorly understood. We hypothesized that visual working memory (VWM) maintains online face representations that are sensitive to physical cues of trustworthiness, and that differences among individuals in representing untrustworthy faces are associated with individual differences in anxiety. Participants performed a change detection task that required encoding and maintaining for a short interval the identity of one face parametrically manipulated to be either trustworthy or untrustworthy. The sustained posterior contralateral negativity (SPCN), an event-related component (ERP) time-locked to the onset of the face, was used to index the resolution of face representations in VWM. Results revealed greater SPCN amplitudes for trustworthy faces when compared with untrustworthy faces, indicating that VWM is sensitive to physical cues of trustworthiness, even in the absence of explicit trustworthiness appraisal. In addition, differences in SPCN amplitude between trustworthy and untrustworthy faces correlated with participants' anxiety, indicating that healthy college students with sub-clinical high anxiety levels represented untrustworthy faces in greater detail compared with students with sub-clinical low anxiety levels. This pattern of findings is discussed in terms of the high flexibility of aversive/avoidance and appetitive/approach motivational systems.

In this quantitative review, we examined the magnitude of attentional biases to negative stimuli in depression. Results from 29 empirical studies examining emotional Stroop or dot probe results in depressed participants (clinical depression, nonclinical dysphoria, and subjects undergoing depressive mood induction) were examined. Studies using the emotional Stroop task yielded marginally significant evidence of a difference between depressed and nondepressed samples, whereas those using the dot probe task showed significant differences between groups (d = 0.52). We found no evidence for significant moderation of these effects by age, sex, type of depressed sample, year of publication, stimulus presentation duration, or type of stimuli (verbal or nonverbal), although statistical power for these tests was limited. These results support the existence of biased attention to negative information in depression.

Acute psychological stress impairs higher-order cognitive function such as working memory (WM). Similar impairments are seen in various psychiatric disorders that are associated with higher susceptibility to stress and with prefrontal cortical dysfunctions, suggesting that acute stress may play a potential role in such dysfunctions. However, it remains unknown whether acute stress has immediate effects on WM-related prefrontal activity.

During stress, attentional capture by threatening stimuli may be particularly adaptive. Individuals are more efficient at identifying threatening faces in a crowd than identifying nonthreatening faces (e.g., öhman et al., Journal of Experimental Psychology: General, 130(3): 466-478, 2001a, öhman et al., Journal of Personality and Social Psychology, 80(3): 381-396, 2001b). However, under conditions of stress, when attention to threat may be most critical, cognitive processes are generally disrupted. The present study explored the attentional advantage of threatening stimuli under stressful conditions. We exposed participants to either high or low stress conditions during a visual search task displaying threatening and nonthreatening facial targets among distractors. Participants' accuracy, reaction times, and self-reported stress were measured. Stress introduced a speed-accuracy trade-off: participants in the high-stress condition were faster, but less accurate, than participants in the low-stress condition. Although both groups of participants showed relative performance advantages in detecting threatening compared with nonthreatening stimuli, this advantage was markedly larger for participants in the high-stress condition. This suggests that the established stress-mediated increase in the activity of the ventral neural network responsible for the reorienting of attention may have enhanced the ability to detect threatening stimuli or buffered the disruptive effects of stress on this process. Our findings highlight the potentially adaptive nature of stress disruption on attentional processes and align research on the anger superiority effect and automated attentional processes under stress.

AbstractThe dot probe task is often used to assess attentional bias in anxiety, but some aspects need clarification. First, the results, which are traditionally summarized in an attentional bias index, do not allow for distinguishing between different selective attention processes; orienting and disengagement. Second, different versions of the dot probe task have been used with unknown relative merits. Participants (N=133) completed two versions of the dot probe task: the detection task (i.e. is there a probe?) and the differentiation task (i.e. what sort of probe is it?). The analysis carried out allowed for a differentiation between orienting and disengagement. The main finding was that trait anxiety is related to disengagement difficulties and not to speed of orienting. Concerning the relative merits of the two dot probe task versions, the results suggest that the detection task may be superior to the differentiation task. Implications for past and future research are discussed.]]>

FOR THE SELECTION OF RELEVANT INFORMATION OUT OF A CONTINUOUS STREAM OF INFORMATION, WHICH IS A COMMON DEFINITION OF ATTENTION, TWO CORE MECHANISMS ARE ASSUMED: a competition-based comparison of the neuronal activity in sensory areas and the top-down modulation of this competition by frontal executive control functions. Those control functions are thought to bias the processing of information toward the intended goals. Acute stress is thought to impair these frontal functions through the release of cortisol. In the present study, subjects had to detect a luminance change of a stimulus and ignore more salient but task irrelevant orientation changes. Before the execution of this task, subjects underwent a socially evaluated cold pressor test (SECPT) or a non-stressful control situation. The SECPT revealed reliable stress response with a significant increase of cortisol and alpha-amylase. Stressed subjects showed higher error rates than controls, particularly in conditions which require top-down control processing to bias the less salient target feature against the more salient and spatially separated distracter. By means of the EEG, subjects who got stressed showed a reduced allocation to the relevant luminance change apparent in a modulation of the N1pc. The following N2pc, which reflects a re-allocation of attentional resources, supports the error pattern. There was only an N2pc in conditions, which required to bias the less salient luminance change. Moreover, this N2pc was decreased as a consequence of the induced stress. These results allow the conclusion that acute stress impairs the intention-based attentional allocation and enhances the stimulus-driven selection, leading to a strong distractibility during attentional information selection.

Much is known about the mechanisms by which attention is focused to facilitate perception, but little is known about what happens to attention after perception of the attended object is complete. One possibility is that the focus of attention passively fades. A second possibility is that attention is actively terminated after the completion of perception so that the brain can be prepared for the next target. The present study investigated this issue with event-related potentials in humans, focusing on the N2pc component (a neural measure of attentional deployment) and the Pd component (a neural measure of attentional suppression). We found that active suppression occurred both to prevent the allocation of attention to known distractors and to terminate attention after the perception of an attended object was complete. In addition, the neural measure of active suppression was correlated with a behavioral measure of trial-to-trial variations in the allocation of attention. Active suppression therefore appears to be a general-purpose mechanism that both prevents and terminates the allocation of attention.

SummaryThe cold-pressor test (CPT) in which subjects immerse their hand in ice water is among the most commonly used laboratory stressors. While the CPT elicits strong sympathetic nervous system activation, cortisol elevations indicative for the reactivity of the hypothalamus–pituitary–adrenal (HPA) axis are moderate to low in response to the CPT. In the present study, we assessed whether cortisol responses to the CPT can be increased by adding social-evaluative elements. Therefore, 70 healthy young men immersed their hand in ice or warm water and were watched by a woman and videotaped during hand immersion or not. While the standard CPT and the socially evaluated cold-pressor test (SECPT) led to comparable increases in blood pressure and subjective stress ratings, saliva cortisol elevations and the proportion of subjects showing a saliva cortisol response (defined as increase >2 nmol/l) were significantly higher after the SECPT. Social evaluation during hand immersion in warm water did not affect saliva cortisol levels suggesting that both social evaluation and a challenge are required for HPA axis activation. These findings indicate that the incorporation of social-evaluative elements increases HPA axis responses to the CPT. The SECPT can serve as a tool for future stress research.]]>

Stress is a well-known modulator of cognitive functions. These effects are, at least in part, mediated by glucocorticoid stress hormones which act via two receptor types in the brain, glucocorticoid receptors (GR) and mineralocorticoid receptors (MR). Here, we examined whether stress affects inhibitory control processes and, if so, whether these effects are mediated by the MR. To this end, healthy participants received 300 mg of the MR antagonist spironolactone or a placebo and underwent a stressor (socially evaluated cold pressor test) or a non-stressful control task 90 min later. Shortly after the stressor, participants performed a stop-signal task that required them to rapidly suppress a well-established response whenever a tone was presented. Results revealed that stress enhanced response inhibition in the stop-signal task and that this enhancement was abolished by spironolactone. Our results show that stress may facilitate inhibitory control and that these effects depend on MR functioning. (C) 2013 Elsevier Ltd.

It is well known that stressful experiences may affect learning and memory processes. Less clear is the exact nature of these stress effects on memory: both enhancing and impairing effects have been reported. These opposite effects may be explained if the different time courses of stress hormone, in particular catecholamine and glucocorticoid, actions are taken into account. Integrating two popular models, we argue here that rapid catecholamine and non-genomic glucocorticoid actions interact in the basolateral amygdala to shift the organism into a 'memory formation mode' that facilitates the consolidation of stressful experiences into long-term memory. The undisturbed consolidation of these experiences is then promoted by genomic glucocorticoid actions that induce a 'memory storage mode', which suppresses competing cognitive processes and thus reduces interference by unrelated material. Highlighting some current trends in the field, we further argue that stress affects learning and memory processes beyond the basolateral amygdala and hippocampus and that stress may pre-program subsequent memory performance when it is experienced during critical periods of brain development. (C) 2011 Elsevier Ltd.

Ten years ago, the Socially Evaluated Cold Pressor Test (SECPT) was introduced as a standardized protocol for the efficient experimental stress induction in humans. In short, the 3 min SECPT, which can be conducted by only a single experimenter, combines a physiological challenge (hand immersion into ice water) with socio-evaluative elements. The purpose of this article is twofold. First, we aim to evaluate the subjective and physiological responses elicited by the SECPT. To this end, we pooled data from 21 studies from our lab and systematically analyzed the response profile to the SECPT. Our analyses show that the SECPT leads, both in men and women, to striking increases in subjective stress levels, autonomic arousal, and cortisol, albeit the cortisol response is typically somewhat less pronounced than in the Trier Social Stress Test. Second, we aim to provide guidelines for conducting the SECPT, in order to foster homogenization of the SECPT procedure across (and within) labs. In sum, we argue that the SECPT is a highly efficient tool to induce stress and activate major stress systems in a laboratory context, in particular if the guidelines that we outline here are followed.

The goal of the present investigation was to discover whether visual working memory maintenance for faces is modulated by facial expression using event-related potentials (ERPs). Each trial consisted of two sequential arrays, a memory array and a test array, each including either two or four faces with neutral or fearful expressions. The faces were displayed to the left and to the right of a central fixation cross. Two central arrows cued participants to encode one face or two faces displayed on one side of the memory array. The sustained posterior contralateral negativity (SPCN) component of the ERP time-locked to the onset of the memory array was used as an index of visual working memory maintenance. Visual working memory performance was quantified using indexes of memory capacity (Cowan's K and K-iterative), a standard index of sensitivity (d'), and reaction times (RTs). Relative to neutral faces, superior memory and longer change-detection RTs to fearful face identities were observed when two faces were displayed on the cued side of the memory array. Fearful faces elicited an enhanced SPCN relative to neutral faces, especially when only one face was displayed on the cued side of the memory array. These findings suggest increased maintenance in visual working memory of faces with a fearful expression relative to faces with a neutral expression and that the representational format in which fearful faces are stored in memory may be characterized by enhanced resolution relative to that subtended in the maintenance of neutral faces.

Stress can fundamentally alter neural responses to incoming information. Recent research suggests that stress and anxiety shift the balance of attention away from a task-directed mode, governed by prefrontal cortex, to a sensory-vigilance mode, governed by the amygdala and other threat-sensitive regions. A key untested prediction of this framework is that stress exerts dissociable effects on different stages of information processing. This study exploited the temporal resolution afforded by event-related potentials to disentangle the impact of stress on vigilance, indexed by early perceptual activity, from its impact on task-directed cognition, indexed by later postperceptual activity in humans. Results indicated that threat of shock amplified stress, measured using retrospective ratings and concurrent facial electromyography. Stress also double-dissociated early sensory-specific processing from later task-directed processing of emotionally neutral stimuli: stress amplified N1 (184-236 ms) and attenuated P3 (316-488 ms) activity. This demonstrates that stress can have strikingly different consequences at different processing stages. Consistent with recent suggestions, stress amplified earlier extrastriate activity in a manner consistent with vigilance for threat (N1), but disrupted later activity associated with the evaluation of task-relevant information (P3). These results provide a novel basis for understanding how stress can modulate information processing in everyday life and stress-sensitive disorders.

Robotic-arm assisted surgery aims to reduce manual errors and improve the accuracy of implant positioning and orientation during total hip arthroplasty (THA). The objective of this study was to assess the surgical team's learning curve for robotic-arm assisted acetabular cup positioning during THA.

D ). EEG data were collected from healthy young adults and typically developing children (9-15 years old) as they searched for a shape singleton target in either the absence or the presence of a salient-but-irrelevant color singleton distractor. The ERP results showed that a lateral shape target elicited a smaller N2pc in children compared with adults regardless of whether a distractor was present or not. Moreover, the target-elicited N2pc was always followed by a similar positivity in both age groups. Counterintuitively, a lateral salient-but-irrelevant distractor elicited a large PD in children with low behavioral accuracy, whereas high-accuracy children exhibited a small and "adult-like" PD . More importantly, we found no evidence for a correlation between the target-elicited N2pc and the distractor-elicited PD in either age group. Our results provide neurophysiological evidence for the developmental differences between target selection and distractor suppression. Compared with adults, 9-15-year-old children deploy insufficient attentional selection resources to targets but use "adult-like" or even more attentional suppression resources to resist irrelevant distractors. A video abstract of this article can be viewed at: https://www.youtube.com/watch?v=NhWapx0d75I.]]>

Social anxiety is characterized by biased attentional processing of social information. However, heterogeneity of extant findings suggests that it may be informative to elucidate individual difference factors that modulate the processing of emotional information. The current study examined whether individual differences in components of attentional control (AC--shifting and focusing) moderated the link between social anxiety and attentional engagement and disengagement biases for threat-relevant cues.

The survival and well-being of all species requires appropriate physiological responses to environmental and homeostatic challenges. The re- establishment and maintenance of homeostasis entails the coordinated activation and control of neuroendocrine and autonomic stress systems. These collective stress responses are mediated by largely overlapping circuits in the limbic forebrain, the hypothalamus and the brainstem, so that the respective contributions of the neuroendocrine and autonomic systems are tuned in accordance with stressor modality and intensity. Limbic regions that are responsible for regulating stress responses intersect with circuits that are responsible for memory and reward, providing a means to tailor the stress response with respect to prior experience and anticipated outcomes.

A vital component of an organism's response to acute stress is a surge in vigilance that serves to optimize the detection and assessment of threats to its homeostasis. The amygdala is thought to regulate this process, but in humans, acute stress and amygdala function have up to now only been studied in isolation. Hence, we developed an integrated design using functional magnetic resonance imaging to investigate the immediate effects of controlled stress induction on amygdala function.

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Acute psychosocial stress in humans triggers the release of glucocorticoids (GCs) and influences performance in declarative and working memory (WM) tasks. These memory systems rely on the hippocampus and prefrontal cortex (PFC), where GC-binding receptors are present. Previous studies revealed contradictory results regarding effects of acute stress on WM-related brain activity. We combined functional magnetic resonance imaging with a standardized psychosocial stress protocol to investigate the effects of acute mental stress on brain activity during encoding, maintenance, and retrieval of WM. Participants (41 healthy young men) underwent either a stress or a control procedure before performing a WM task. Stress increased salivary cortisol levels and tended to increase WM accuracy. Neurally, stress-induced increases in cortical activity were evident in PFC and posterior parietal cortex (PPC) during WM maintenance. Furthermore, hippocampal activity was modulated by stress during encoding and retrieval with increases in the right anterior hippocampus during WM encoding and decreases in the left posterior hippocampus during retrieval. Our study demonstrates that stress increases activity in PFC and PPC specifically during maintenance of items in WM, whereas effects on hippocampal activity are restricted to encoding and retrieval. The finding that psychosocial stress can increase and decrease activity in two different hippocampal areas may be relevant for understanding the often-reported phase-dependent opposing behavioral effects of stress on long-term memory.

A key component of acute stress is a surge in vigilance that enables a prioritized processing of highly salient information to promote the organism's survival. In this study, we investigated the neural effects of acute stress on emotional picture processing. ERPs were measured during a deep encoding task, in which 40 male participants categorized 50 unpleasant and 50 neutral pictures according to arousal and valence. Before picture encoding, participants were subjected either to the Socially Evaluated Cold Pressor Test (SECPT) or to a warm water control procedure. The exposure to the SECPT resulted in increased subjective and autonomic (heart rate and blood pressure) stress responses relative to the control condition. Viewing of unpleasant relative to neutral pictures evoked enhanced late positive potentials (LPPs) over centro-parietal scalp sites around 400 msec after picture onset. Prior exposure to acute stress selectively increased the LPPs for unpleasant pictures. Moreover, the LPP magnitude for unpleasant pictures following the SECPT was positively associated with incidental free recall performance 24 hr later. The present results suggest that acute stress sensitizes the brain for increased processing of cues in the environment, particularly priming the processing of unpleasant cues. This increased processing is related to later long-term memory performance.

Exposure to long-term stress has a variety of consequences on the brain and cognition. Few studies have examined the influence of long-term stress on event related potential (ERP) indices of error processing. The current study investigated how long-term academic stress modulates the error related negativity (Ne or ERN) and the error positivity (Pe) components of error processing. Forty-one male participants undergoing preparation for a major academic examination and 20 non-exam participants completed a Go-NoGo task while ERP measures were collected. The exam group reported higher perceived stress levels and showed increased Pe amplitude compared with the non-exam group. Participants' rating of the importance of the exam was positively associated with the amplitude of Pe, but these effects were not found for the Ne/ERN. These results suggest that long-term academic stress leads to greater motivational assessment of and higher emotional response to errors. (C) 2014 Elsevier B.V.

attentional bias towards threat is a common phenomenon in anxious as well as healthy individuals. There are two potential cognitive mechanisms of attentional bias. The facilitated attentional orienting is known as threat stimuli are detected faster than neutral stimuli. The impaired attentional disengagement is defined as harder to disengage attention from threat stimuli compare to neutral stimuli. The amygdala- anterior cingulate cortex network is the potential neural base of facilitated attentional orienting, while the orbitofrontal cortex is the key area of attentional disengagement. The properties of threat stimuli and characteristic of participants are main factors which affect attentional bias. The future studies should focus on the relationship between attentional orienting and attentional disengagement as well as the neural base of attentional bias.