Threat Signals Research Articles

Endogenous cortisol reactivity moderates the relationship between fear inhibition to safety signals and posttraumatic stress disorder symptoms

ObjectivePosttraumatic stress symptoms (PTSS) are commonly associated with impairments in extinguishing fear to signals previously associated with danger, and also with inhibiting fear to safety signals. Previous studies indicate that PTSS are associated with low cortisol activity, and cortisol is shown to facilitate fear extinction. Few studies have examined the influence of cortisol reactivity on fear extinction in PTSS. MethodWe used a standardized fear conditioning and extinction paradigm to investigate the relationship between fear extinction and endogenous salivary cortisol activity in participants with high PTSS (n=18), trauma-exposed controls (n=33), and non-trauma-exposed controls (n=27). Skin conductance response (SCR) was used as an index of conditioned responding. Saliva samples were collected at baseline, and 20min post-fear acquisition for basal and reactive cortisol levels, respectively. ResultsPTSS participants demonstrated a slower rate of extinction learning during the early extinction phase. A moderation analysis revealed that cortisol reactivity was a significant moderator between fear inhibition to the safety signal (CS−) during early extinction and PTSS, but not to the threat signal (CS+). Specifically, this interaction was significant in two ways: (1) participants with elevated cortisol reactivity showed lower PTSS as fear inhibition improved; and (2) participants with low cortisol reactivity showed higher PTSS as fear inhibition improved. ConclusionThe findings of the present study show that the relationship between fear inhibition and cortisol reactivity is complex, and suggest that cortisol reactivity shapes safety signal learning in PTSS.

Dynamic Search Mechanism with Threat Prediction in a GNSS Receiver

With the development of GNSS and the application of multimode signals, efficient GNSS receiver research has become very important. However, threat signals in the received signal are inevitable, which will represent important threats to navigation applications and will lead to leakage and fault detection for the receiver. Therefore, the searches with threat prediction in GNSS signals have been regarded as the important problem for GNSS receivers. In view of the limitations and nonadaptability of the current search technologies as well as on the basis of the proportionality peak judgment mechanism, a dynamic search mechanism with threat prediction (DSM-TP) is proposed in this paper, in which we define a series of preset coefficients and a threat index to optimize the decision mechanism. The simulation results demonstrate that the DSM-TP method can predict the threat situation and can adapt to lower SNR environments compared to the traditional method. In addition, the DSM-TP method can avoid the impact of threats, and the detection capability of the new method is better than the detection capability of the traditional method.

Under Conviction: “Real Men” Reborn on Spiritual and Cinematic Battlefields

While situating my ethnographic fieldwork at Mars Hill Church of Seattle from 2006–2008, this paper examines how processes of corporatization and militarization were structurally embedded through the circulation of fear, shame, and paranoia in the virtual, visual, and visceral networking of Pastor Mark Driscoll's posture in voice. Specifically, this paper examines teaching on biblical masculinity in tandem with Mars Hill's promotion of a militarized and sexualized visual culture as a methodology of cultural politics that conflated freedom and control while bodily recruiting evangelical ‘citizen-soldiers’ into everyday spiritual warfare on mission to expand the church's empire. I argue this ethos of battle readiness manifested through the felt reality of emergent threat signals an affective political economy conscripting U.S. citizen-soldiers through cultural politics writ large to participate in the ongoing ‘global’ war on terror ‘at home.’ By reassessing the political valences of ‘conviction’ in terms of ‘gut feeling’ which signals desires simultaneously biological and social that can be suggested and manipulated through the affective priming of mood and atmosphere, this paper examines the bodily affects and political effects of conviction as resonant across spaces deemed religious and secular to index and critique intersecting aims of Evangelical and U.S. Empire amplifying biopolitical control in the name of freedom.

The Basolateral Amygdalae and Frontotemporal Network Functions for Threat Perception.

Although the amygdalae play a central role in threat perception and reactions, the direct contributions of the amygdalae to specific aspects of threat perception, from ambiguity resolution to reflexive or deliberate action, remain ill understood in humans. Animal studies show that a detailed understanding requires a focus on the different subnuclei, which is not yet achieved in human research. Given the limits of human imaging methods, the crucial contribution needs to come from individuals with exclusive and selective amygdalae lesions. The current study investigated the role of the basolateral amygdalae and their connection with associated frontal and temporal networks in the automatic perception of threat. Functional activation and connectivity of five individuals with Urbach–Wiethe disease with focal basolateral amygdalae damage and 12 matched controls were measured with functional MRI while they attended to the facial expression of a threatening face–body compound stimuli. Basolateral amygdalae damage was associated with decreased activation in the temporal pole but increased activity in the ventral and dorsal medial prefrontal and medial orbitofrontal cortex. This dissociation between the prefrontal and temporal networks was also present in the connectivity maps. Our results contribute to a dynamic, multirole, subnuclei-based perspective on the involvement of the amygdalae in fear perception. Damage to the basolateral amygdalae decreases activity in the temporal network while increasing activity in the frontal network, thereby potentially triggering a switch from resolving ambiguity to dysfunctional threat signaling and regulation, resulting in hypersensitivity to threat.

Design of Dynamic Reconfigurable Structure Based on Integrated Filter Banks

In electronic confrontation, radar confrontation is an important part. Various radars widely used in modern warfare are the most important equipment in the field of information acquisition and precision guidance. Especially in the vast battle space, in order to achieve timely, accurate and comprehensive access to various target information, the role of radar is irreplaceable. Especially in the vast battle space, the role of radar is irreplaceable in order to achieve timely, accurate and comprehensive access to various target information. Therefore, in the war, it will not be able to protect their own survival and play combat effectiveness if not having the radar's ability to fight. At this time, that is the need for radar equipment in time to detect radar exposure, rapid measurement of radar signal parameters and identify threat signals, and targeted to do the implementation of interference or the implementation of technical attacks. In order to extract the parameters of the received signal to facilitate the subsequent research and analysis, this paper deduces the structure of the integrated filter bank in detail, and gives the reconfigurable filter bank structure design method, under the condition of accurate reconstruction of the signal. Based on the analysis of the design and calculation complexity of the filter bank structure, the dynamic reconfigurable design method con-sumes less hardware resources and wide application range, and the simulation structure also verifies the correctness and flexibility of the structure.

Endogenous testosterone is associated with lower amygdala reactivity to angry faces and reduced aggressive behavior in healthy young women.

Testosterone and cortisol have been proposed to influence aggressive behavior by altering the neural processing of facial threat signals. However, this has not been investigated in direct social interactions. Here, we explored the joint impact of testosterone, cortisol, and brain reactivity to anger expressions on women’s reactive aggression in the Social Threat Aggression Paradigm (STAP). The STAP is a competitive reaction time task in which the purported opponent displays either an angry or a neutral facial expression at the beginning of each trial and delivers increasingly loud sound blasts to the participants, successfully provoking them. Strikingly, salivary testosterone at scan-time was negatively related to both aggression and basolateral amygdala (BLA) reactivity to angry faces, whereas cortisol had no effect. When the opponent looked angry, BLA-orbitofrontal coupling was reduced, and BLA reactivity was positively related to aggression. The latter relationship was fully mediated by bilateral superior temporal gyrus (STG) activation. Our results thus support previous neurobiological models of aggression, and extend them by demonstrating that fast amygdala responses to threat modulate STG activity in order to favor aggressive retaliation. Furthermore, our study agrees with recent evidence underscoring a fear-reducing and strategically prosocial effect of testosterone on human social behavior.

Greater Attention to Task-Relevant Threat Due to Orbitofrontal Lesion.

Injury to the orbitofrontal cortex (OFC) is a frequent consequence of head injury and may lead to dysfunctional regulation of emotional and social behavior. Dysfunctional emotional behavior may partly be related to the role of the OFC in emotion-attention interaction, as reported previously. In order to better understand its role in emotion-attention and emotion-cognitive control interactions, we investigated attention allocation to task-relevant and task-irrelevant threat-related emotional stimuli during a task requiring cognitive control in patients with lesion to the OFC. We measured the behavioral performance and event-related potentials (ERP) of 13 patients with OFC lesion and 11 control subjects during a Go/NoGo visual discrimination task. In the task, line drawings of threatening (spider) and neutral (flower) figures served as either task-relevant Go or NoGo signals, or as task-irrelevant distractors. Overall performance did not differ between the groups. In contrast to the control group performance, the orbitofrontal group performance was improved by relevant threat signal in comparison with neutral signal. Further, task-relevant threat signals evoked larger frontocentral N2-P3 amplitude in the orbitofrontal group. Taken together, behavioral and electrophysiological results suggest that patients with OFC injury allocated more attentional and cognitive control resources in the context of task-relevant emotional stimuli. This study provides new evidence for the role of the OFC in emotion-attention and emotion-cognitive control interactions. Further, the OFC seems to contribute to the balance between voluntary and involuntary attention networks in context of emotional stimuli. Better understanding of alterations in emotion-attention interaction offers insight into affective dysfunction due to OFC lesion.

Desperately Seeking Support

Much is unknown about adult attachment style formation. We investigate whether negative reinforcement schedules promote hallmark features of secure and anxious attachment styles in a shock threat support-seeking paradigm. Participants ostensibly asked for help from another participant seated in another room. Each time a shock threat signal appeared they were to press a button to indicate their need for help. The supporter could then stop the imminent shock. The reliability of the supporters was varied such that some supporters were consistent (continuous reinforcement) whereas others were inconsistent (variable ratio reinforcement). Results indicated that inconsistently responsive others, reinforcing on a variable ratio schedule, led to heightened approach-related attentional biases toward the supporter, measured by event-related potentials, increased positive attachment associations with the supporter, implicitly measured via a lexical decision task, and more negative explicit evaluations of the supporter.

Loud and angry: sound intensity modulates amygdala activation to angry voices in social anxiety disorder.

Angry expressions of both voices and faces represent disorder-relevant stimuli in social anxiety disorder (SAD). Although individuals with SAD show greater amygdala activation to angry faces, previous work has failed to find comparable effects for angry voices. Here, we investigated whether voice sound-intensity, a modulator of a voice’s threat-relevance, affects brain responses to angry prosody in SAD. We used event-related functional magnetic resonance imaging to explore brain responses to voices varying in sound intensity and emotional prosody in SAD patients and healthy controls (HCs). Angry and neutral voices were presented either with normal or high sound amplitude, while participants had to decide upon the speaker’s gender. Loud vs normal voices induced greater insula activation, and angry vs neutral prosody greater orbitofrontal cortex activation in SAD as compared with HC subjects. Importantly, an interaction of sound intensity, prosody and group was found in the insula and the amygdala. In particular, the amygdala showed greater activation to loud angry voices in SAD as compared with HC subjects. This finding demonstrates a modulating role of voice sound-intensity on amygdalar hyperresponsivity to angry prosody in SAD and suggests that abnormal processing of interpersonal threat signals in amygdala extends beyond facial expressions in SAD.

Was that a threat? A cueing study on attentional guidance by threat signals

Research indicates that stimuli signaling threat may capture and hold attention. However, whether threat signals have a true effect on perception and attention or if this effect results merely from arousal and response activation is still a matter of debate. 34 volunteers completed a modified spatial-emotional cueing paradigm to examine how perceptual sensitivity (d') and response times (RT) were affected by a threatening stimulus. The color of one cue was paired with a chance to receive an electric shock, the others were neutral. Two colored circles were presented as cues at each side of fixation, one of which could be associated with a shock. Following the cues, two Gabor patches were presented; one of which was tilted and served as target. The target Gabor patch could be presented at the location of the threat-associated cue (Cued) or on the opposite side (Uncued). Stimulus onset asynchrony (SOA) between cue and target was either 100ms or 1000ms. The results showed, relative to the neutral condition, an increased perceptual sensitivity (d') and faster RTs for targets appearing at the location where the threat associated cue was presented and lower d' and slower RTs for targets appearing at opposite side of the threatening cue. This indicates that, immediately after cue presentation, attention is captured by the threat-associated cue, evidenced by the higher d' for detecting targets at the cued versus the uncued locations at the short SOA. Crucially, this enhanced perceptual sensitivity remained present for the long SOA, suggesting that attention remains focused at the location of the threatening stimulus even 1000 ms after it was extinguished. RT measures followed a similar pattern. The current results show an effect of threatening stimuli on perceptual selectivity (d'), providing unequivocal evidence that threatening stimuli can modulate the efficacy of sensory processing. Meeting abstract presented at VSS 2016

Computer animations of color markings reveal the function of visual threat signals in Neolamprologus pulcher.

Visual signals, including changes in coloration and color patterns, are frequently used by animals to convey information. During contests, body coloration and its changes can be used to assess an opponent’s state or motivation. Communication of aggressive propensity is particularly important in group‐living animals with a stable dominance hierarchy, as the outcome of aggressive interactions determines the social rank of group members. Neolamprologus pulcher is a cooperatively breeding cichlid showing frequent within-group aggression. Both sexes exhibit two vertical black stripes on the operculum that vary naturally in shape and darkness. During frontal threat displays these patterns are actively exposed to the opponent, suggesting a signaling function. To investigate the role of operculum stripes during contests we manipulated their darkness in computer animated pictures of the fish. We recorded the responses in behavior and stripe darkness of test subjects to which these animated pictures were presented. Individuals with initially darker stripes were more aggressive against the animations and showed more operculum threat displays. Operculum stripes of test subjects became darker after exposure to an animation exhibiting a pale operculum than after exposure to a dark operculum animation, highlighting the role of the darkness of this color pattern in opponent assessment. We conclude that (i) the black stripes on the operculum of N. pulcher are a reliable signal of aggression and dominance, (ii) these markings play an important role in opponent assessment, and (iii) 2D computer animations are well suited to elicit biologically meaningful short-term aggressive responses in this widely used model system of social evolution.

Self-relevant threat contexts enhance early processing of fear-conditioned faces

Anxiety states are characterized by attentional biases to threat and increased early brain responses to potentially threat signaling stimuli. How such stimuli are processed further depends on prior learning experiences (e.g. conditioning and extinction) and the context in which a stimulus appears. Whether context information and prior learning experiences interact with early threat processing in humans is largely unknown. Here, EEG was recorded while healthy participants (N=20) viewed faces that were fear-conditioned and/or extinguished 24h before. Faces were either passively viewed or presented within different contexts, which were created by describing scenarios that could either involve participants directly (self-threatening), or made them observers (other-threatening) of a potentially dangerous situation. Early brain responses (i.e., P1 amplitudes) were specifically enhanced during the self-threatening condition in response to non-extinguished versus extinguished fear-conditioned faces. This finding suggests that top-down contextual information is incorporated into early attention modulation of previously learned threat signals.

Amygdala hyperactivation to angry faces in intermittent explosive disorder

BackgroundIndividuals with intermittent explosive disorder (IED) were previously found to exhibit amygdala hyperactivation and relatively reduced orbital medial prefrontal cortex (OMPFC) activation to angry faces while performing an implicit emotion information processing task during functional magnetic resonance imaging (fMRI). This study examines the neural substrates associated with explicit encoding of facial emotions among individuals with IED. MethodTwenty unmedicated IED subjects and twenty healthy, matched comparison subjects (HC) underwent fMRI while viewing blocks of angry, happy, and neutral faces and identifying the emotional valence of each face (positive, negative or neutral). We compared amygdala and OMPFC reactivity to faces between IED and HC subjects. We also examined the relationship between amygdala/OMPFC activation and aggression severity. ResultsCompared to controls, the IED group exhibited greater amygdala response to angry (vs. neutral) facial expressions. In contrast, IED and control groups did not differ in OMPFC activation to angry faces. Across subjects amygdala activation to angry faces was correlated with number of prior aggressive acts. ConclusionsThese findings extend previous evidence of amygdala dysfunction in response to the identification of an ecologically-valid social threat signal (processing angry faces) among individuals with IED, further substantiating a link between amygdala hyperactivity to social signals of direct threat and aggression.

The time course of attentional bias to cues of threat and safety

ABSTRACTIt is well known that relative to neutral stimuli, attention is biased towards processing stimuli that convey threat. In a previous study in which a particular stimulus (e.g. a blue diamond) was associated with the delivery of an electrical shock, the presence of the fear-conditioned stimulus interfered with the execution of voluntary eye movements to other locations. Here, we show that this effect not only occurs early in time, but remains present long after the fear-conditioned stimulus was removed from the screen. In a subsequent experiment, we associated the presence of a particular stimulus with safety, that is, when this stimulus was present it was certain that no electrical shock would be delivered. The presence of the safety signalling stimulus also interfered with the execution of voluntary saccades, but only when the time between stimulus and cue presentation was relatively long. The results indicate that both signals of threat and signals of safety interfere with execution of a saccade long after the source of threat or safety has been removed. However, only threatening stimuli affect saccade execution early in time, suggesting that threatening stimuli drive selection exogenously.

The impact of high trait social anxiety on neural processing of facial emotion expressions in females

A cognitive model of social anxiety predicts that an early attentional bias leads to greater cognitive processing of social threat signals, whereas the vigilance-avoidance model predicts there will be subsequent reduction in cognitive processing. This study tests these models by examining neural responses to social threat stimuli using Event-related potentials (ERP). 19 women with high trait social anxiety and 19 women with low trait social anxiety viewed emotional expressions (angry, disgusted, happy and neutral) in a passive viewing task whilst ERP responses were recorded. The HSA group revealed greater automatic attention, or hypervigilance, to all facial expressions, as indexed by greater N1 amplitude compared to the LSA group. They also showed greater sustained attention and elaborative processing of all facial expressions, indexed by significantly increased P2 and P3 amplitudes compared to the LSA group. These results support cognitive models of social anxiety, but are not consistent with predictions of the vigilance-avoidance model.

Wrażliwość na wzmocnienia a zazdrość w związkach romantycznych

Jealousy is an adaptive emotional reaction that signals threat to the current romantic relationship and motivates the person to protect that relationship. Given that jealousy is a mechanism of sensitivity to signals of relational threat, it was predicted that neurobiological systems of fight-flight- -freeze (FFFS) and behavioral inhibition (BIS) would be positively correlated with emotional jealousy. It was also predicted that these associations would be stronger in individuals highly committed to their relationships. We examined the mediatory role of approach-avoidance social goals in relations between BIS, FFFS, behavioral activation system (BAS), and the experience of jealousy. The present study was conducted on a group of 217 participants aged between 17 and 36 years, involved in romantic relationships. The results showed that the sensitivity of BIS and the freeze system (FFFS) was correlated positively with the intensity of jealousy. Commitment appeared to moderate the relations between FFFS and the intensity of jealousy. Avoidance social goals mediated the relation between BIS and the intensity of jealousy.

Wrażliwość na wzmocnienia a zazdrość w związkach romantycznych

Jealousy is an adaptive emotional reaction that signals threat to the current romantic relationship and motivates the person to protect that relationship. Given that jealousy is a mechanism of sensitivity to signals of relational threat, it was predicted that neurobiological systems of fight-flight- -freeze (FFFS) and behavioral inhibition (BIS) would be positively correlated with emotional jealousy. It was also predicted that these associations would be stronger in individuals highly committed to their relationships. We examined the mediatory role of approach-avoidance social goals in relations between BIS, FFFS, behavioral activation system (BAS), and the experience of jealousy. The present study was conducted on a group of 217 participants aged between 17 and 36 years, involved in romantic relationships. The results showed that the sensitivity of BIS and the freeze system (FFFS) was correlated positively with the intensity of jealousy. Commitment appeared to moderate the relations between FFFS and the intensity of jealousy. Avoidance social goals mediated the relation between BIS and the intensity of jealousy.

Prefrontal Reactivity to Social Signals of Threat as a Predictor of Treatment Response in Anxious Youth.

Neuroimaging has shown promise as a tool to predict likelihood of treatment response in adult anxiety disorders, with potential implications for clinical decision-making. Despite the relatively high prevalence and emergence of anxiety disorders in youth, very little work has evaluated neural predictors of response to treatment. The goal of the current study was to examine brain function during emotional face processing as a predictor of response to treatment in children and adolescents (age 7-19 years; N=41) with generalized, social, and/or separation anxiety disorder. Prior to beginning treatment with the selective serotonin reuptake inhibitor (SSRI) sertraline or cognitive behavior therapy (CBT), participants completed an emotional faces matching task during functional magnetic resonance imaging (fMRI). Whole brain responses to threatening (ie, angry and fearful) and happy faces were examined as predictors of change in anxiety severity following treatment. Greater activation in inferior and superior frontal gyri, including dorsolateral prefrontal cortex and ventrolateral prefrontal cortex, as well as precentral/postcentral gyri during processing of threatening faces predicted greater response to CBT and SSRI treatment. For processing of happy faces, activation in postcentral gyrus was a significant predictor of treatment response. Post-hoc analyses indicated that effects were not significantly moderated by type of treatment. Findings suggest that greater activation in prefrontal regions involved in appraising and regulating responses to social signals of threat predict better response to SSRI and CBT treatment in anxious youth and that neuroimaging may be a useful tool for predicting how youth will respond to treatment.

Amygdala lesions in rhesus macaques decrease attention to threat.

Evidence from animal and human studies has suggested that the amygdala plays a role in detecting threat and in directing attention to the eyes. Nevertheless, there has been no systematic investigation of whether the amygdala specifically facilitates attention to the eyes or whether other features can also drive attention via amygdala processing. The goal of the present study was to examine the effects of amygdala lesions in rhesus monkeys on attentional capture by specific facial features, as well as gaze patterns and changes in pupil dilation during free viewing. Here we show reduced attentional capture by threat stimuli, specifically the mouth, and reduced exploration of the eyes in free viewing in monkeys with amygdala lesions. Our findings support a role for the amygdala in detecting threat signals and in directing attention to the eye region of faces when freely viewing different expressions.

The fitness consequences of honesty: Under-signalers have a survival advantage in song sparrows.

How honest or reliable signaling can evolve and be maintained has been a major question in evolutionary biology. The question is especially puzzling for a particular class of signals used in aggressive interactions: threat signals. Here, we report a study on song sparrows (Melospiza melodia) in which we assayed males with playbacks on their territories to quantify their aggressiveness (flights and close proximity) and aggressive signaling levels (rates of soft song, a close-range signal reliably predicting attack) and asked whether these traits affect individuals' survival on territory. We found that the effect of aggressive signaling via soft song interacted with aggressive behaviors such that there was a negative correlational selection: among males with low aggression, those males that signaled at higher levels (over-signalers) had higher survival whereas among males with high aggression those that signaled at low levels (under-signalers) survived longer. In other words, males that deviate from reliable signaling have a survival advantage. These results, along with previous research that suggested most of the deviation from reliable signaling in this system is in the form of under-signaling (high-aggression males signaling at low levels) pose a puzzle for future research on how this reliable signaling system is maintained.