Safety Cues Research Articles

Alterations in fear learning as a mechanism linking childhood exposure to violence with PTSD symptoms: a longitudinal study.

Fear learning is a core component of conceptual models of how adverse experiences may influence psychopathology. Specifically, existing theories posit that childhood experiences involving childhood trauma are associated with altered fear learning processes, while experiences involving deprivation are not. Several studies have found altered fear acquisition in youth exposed to trauma, but not deprivation, although the specific patterns have varied across studies. The present study utilizes a longitudinal sample of children with variability in adversity experiences to examine associations among childhood trauma, fear learning, and psychopathology in youth. The sample includes 170 youths aged 10-13 years (M = 11.56, s.d. = 0.47, 48.24% female). Children completed a fear conditioning task while skin conductance responses (SCR) were obtained, which included both acquisition and extinction. Childhood trauma and deprivation severity were measured using both parent and youth report. Symptoms of anxiety, externalizing problems, and post-traumatic stress disorder (PTSD) were assessed at baseline and again two-years later. Greater trauma-related experiences were associated with greater SCR to the threat cue (CS+) relative to the safety cue (CS-) in early fear acquisition, controlling for deprivation, age, and sex. Deprivation was unrelated to fear learning. Greater SCR to the threat cue during early acquisition was associated with increased PTSD symptoms over time controlling for baseline symptoms and mediated the relationship between trauma and prospective changes in PTSD symptoms. Childhood trauma is associated with altered fear learning in youth, which may be one mechanism linking exposure to violence with the emergence of PTSD symptoms in adolescence.

Emotional memory bias in adolescents with chronic pain: examining the relationship with neural, stress, and psychological factors.

Memory biases for pain-related information may contribute to the development and maintenance of chronic pain; however, evidence for when (and for whom) these biases occur is mixed. Therefore, we examined neural, stress, and psychological factors that could influence memory bias, focusing on memories that motivate disabling behaviors: pain perception, conditioned responses to threat-and-safety cues, and responses to aversive nonnoxious stimuli. Two studies were conducted with adolescents with and without chronic pain. Data from 58 participants were included in study 1 (chronic pain n = 34, pain free n = 24, mean age = 16 years), and 39 participants were included in study 2 (chronic pain n = 26, pain free n = 13, mean age = 16 years). Both studies used a threat-safety learning paradigm with memory recall (≈1 month later). Participants completed structural and functional (resting-state) magnetic resonance imaging, salivary cortisol measurements, and self-report measures. Adolescents with pain and pain-free peers consistently recalled being more afraid of safety cues (CS-) and, during heightened stress at encoding (higher cortisol levels), also reported being more afraid of threat cues (CS+). However, no memory bias was present for the emotional response to an aversive stimulus (US; loud scream) or for the recall of pain intensity. Functional connectivity of the amygdala and hippocampus with memory circuits related to the degree of memory bias, but the specific connections varied between the studies, and we observed no relationship between memory bias and brain morphology. Our findings highlight the value of considering the interaction between implicit and explicit memory systems, contributing to a more comprehensive understanding of emotional memory biases in the context of chronic pain.

Ambiguity potentiates effects of loneliness on feelings of rejection

ABSTRACT For social species, having strong and high-quality social relationships is an important safety cue. Loneliness occurs when an individual perceives they have insufficient relationships resulting in feelings of lack of safety. States of perceived unsafety are linked to an increased tendency to construe ambiguous information – information lacking a unique clear interpretation – as threatening. Here, we explore whether the ambiguity of social cues of interpersonal rejection moderates effects of loneliness on feelings of rejection while undergoing social exclusion. Data were collected in 2021; 144 adults completed a progressive social exclusion paradigm where they were randomly assigned to be equally included, excluded, or over-included. Social exclusion/inclusion cues became more pronounced over the course of multiple rounds of a ball-tossing game (Cyberball) resulting in a scenario where ambiguity was highest in earlier rounds and decreased over time. Participants reported feelings of loneliness prior to the task and feelings of rejection throughout the task. Results demonstrated that higher loneliness predicted increased feelings of rejection regardless of exclusion condition. Notably, this positive relationship was strongest during earlier rounds when social cues were most ambiguous. These findings contribute to our understanding of how loneliness modulates social perception to enable organisms to adequately adapt to changing circumstances.

How adverse childhood experiences get under the skin: A systematic review, integration and methodological discussion on threat and reward learning mechanisms.

Adverse childhood experiences (ACEs) are a major risk factor for the development of multiple psychopathological conditions, but the mechanisms underlying this link are poorly understood. Associative learning encompasses key mechanisms through which individuals learn to link important environmental inputs to emotional and behavioral responses. ACEs may impact the normative maturation of associative learning processes, resulting in their enduring maladaptive expression manifesting in psychopathology. In this review, we lay out a systematic and methodological overview and integration of the available evidence of the proposed association between ACEs and threat and reward learning processes. We summarize results from a systematic literature search (following PRISMA guidelines) which yielded a total of 81 articles (threat: n=38, reward: n=43). Across the threat and reward learning fields, behaviorally, we observed a converging pattern of aberrant learning in individuals with a history of ACEs, independent of other sample characteristics, specific ACE types, and outcome measures. Specifically, blunted threat learning was reflected in reduced discrimination between threat and safety cues, primarily driven by diminished responding to conditioned threat cues. Furthermore, attenuated reward learning manifested in reduced accuracy and learning rate in tasks involving acquisition of reward contingencies. Importantly, this pattern emerged despite substantial heterogeneity in ACE assessment and operationalization across both fields. We conclude that blunted threat and reward learning may represent a mechanistic route by which ACEs may become physiologically and neurobiologically embedded and ultimately confer greater risk for psychopathology. In closing, we discuss potentially fruitful future directions for the research field, including methodological and ACE assessment considerations.

The impact of the left inferior frontal gyrus on fear extinction: A transcranial direct current stimulation study

IntroductionFear extinction is a fundamental component of exposure-based therapies for anxiety-related disorders. The renewal of fear in a different context after extinction highlights the importance of contextual factors. In this study, we aimed to investigate the causal role of the left inferior frontal gyrus (LiFG) in the context-dependency of fear extinction learning via administration of transcranial direct current stimulation (tDCS) over this area. Methods180 healthy subjects were assigned to 9 groups: 3 tDCS conditions (anodal, cathodal, and sham) × 3 context combinations (AAA, ABA, and ABB). The fear conditioning/extinction task was conducted over three consecutive days: acquisition, extinction learning, and extinction recall. tDCS (2 mA, 10min) was administered during the extinction learning phase over the LiFG via a 4-electrode montage. Skin conductance response (SCR) data and self-report assessments were collected. ResultsDuring the extinction learning phase, groups with excitability-enhancing anodal tDCS showed a significantly higher fear response to the threat cues compared to cathodal and sham stimulation conditions, irrespective of contextual factors. This effect was stable until the extinction recall phase. Additionally, excitability-reducing cathodal tDCS caused a significant decrease of the response difference between the threat and safety cues during the extinction recall phase. The self-report assessments showed no significant differences between the conditions throughout the experiment. ConclusionIndependent of the context, excitability enhancement of the LiFG did impair fear extinction, and led to preservation of fear memory. In contrast, excitability reduction of this area enhanced fear extinction retention. These findings imply that the LiFG plays a role in the fear extinction network, which seems to be however context-independent.

The fear-avoidance model as an embodied prediction of threat.

The fear-avoidance model is a well-established framework in the understanding of persistent pain. It proposes a dichotomous path: either the context is interpreted as safe; there is no fear reaction and, therefore, the individual engages in active (positive) coping; or the context is interpreted as threatening, leading to a self-reinforcing vicious circle of fear and (negative) avoidance. We propose an embodied interpretation of this phenomenon employing the joint framework of predictive coding and active inference. The key idea is that multisensory integration of exteroceptive, proprioceptive, and interoceptive sensory inputs can lead to dysfunctional experiences of threat in nonthreatening situations. Threat inference can promote fear responses, maladaptive strategies (i.e., avoidance) and self-provides evidence for threat in associated or future contexts, or both. Under this treatment, the prediction of nonrealized threat becomes self-evidencing and context-invariant, and hence self-perpetuating. Safety cues are unable to attenuate the interpretation of the negative context as the dominant inference of the context is threatful and gains more precision and becomes resistant over time. Our model provides an explanation for the emergence of a dysfunctional fear response in the clinical setting despite apparent safety based on modern concepts from theoretical (computational) neuroscience.

Aversive contexts enhance defensive responses to conditioned threat.

The ability to flexibly transition between defensive states is crucial for adaptive responding in life-threatening situations. Potentially threatening situations typically induce a sustained feeling of apprehension in association with hypervigilance, while acute threat is usually characterized by an intense and transient response to cope with the imminent danger. While potential and acute threat states have traditionally been viewed as mutually exclusive, this distinction is being challenged by a growing body of evidence suggesting a more complex interplay during simultaneous activation of these states. However, the interaction between potential and acute threat on a psychophysiological level remains elusive. To fill this gap, 94 healthy individuals participated in one of two contextual fear-conditioning paradigms. In both paradigms, a differential fear-learning phase was conducted, followed by a test phase in which the conditioned stimuli were presented in front of either conditioned or inherently aversive contextual images compared to neutral contexts. To capture defensive responses, we recorded subjective (threat and expectancy ratings) and physiological (electrodermal and cardiovascular) activity to the conditioned stimuli as a function of contextual threat. Besides indices of successful fear conditioning, our results revealed stronger threat and unconditioned stimulus expectancy ratings, cardiac deceleration, and skin conductance responses for threat and safety cues presented in inherently aversive compared to neutral contexts. Conditioned contexts had less impact on physiological responses to threat and safety cues than inherently aversive contexts. These findings provide new insights into the additive nature of defensive responses to fear cues and situations of contextual threat.

Impact of drone-specific dispatch instructions on the safety and efficacy of drone-delivered emergency medical treatments: A randomized simulation pilot study

IntroductionMedical drones have potential for improving the response times to out-of-hospital emergencies. However, widespread adoption is hindered by unanswered questions surrounding medical dispatch and bystander safety. This study evaluated the impact of novel drone-specific dispatch instructions (DSDI) on bystanders’ ability to interact effectively with a medical drone and provide prompt, safe, and high-quality treatment in a simulated emergency scenario.11Drone-specific dispatch instructions. We hypothesized DSDI would improve bystanders’ performance and facilitate safer bystander-drone interactions. MethodsTwenty-four volunteers were randomized to receive either DSDI and standard Medical Priority Dispatch (MPD) instructions or MPD alone in a simulated out-of-hospital cardiac arrest (OHCA) or pediatric anaphylaxis.,22Medical priority dispatch3 Out-of-hospital cardiac arrest.3 Participants in the DSDI group received detailed instructions on locating and interacting with the drone and its enclosed medical kit. The simulations were video recorded. Participants completed a semi-structured interview and survey. ResultsThe addition of DSDI did not lead to statistically significant changes to the overall time to provide care in either the anaphylaxis or OHCA simulations. However, DSDI did have an impact on bystander safety. In the MPD only group, 50% (6/12) of participants ignored the audio and visual safety cues from the drone instead of waiting for it to be declared safe compared to no DSDI participants ignoring these safety cues. ConclusionsAll participants successfully provided patient care. However, this study indicates that DSDI may be useful to ensure bystander safety and should be incorporated in the continued development of emergency medical drones.

Exploring the ‘black box’ of anxiety: An ERP study of non-consciously triggered fear generalization

Individuals with anxiety disorders frequently display heightened fear responses, even in situations where there is no imminent danger. We hypothesize that these irrational fear responses are related to automatic processing of fear generalization. The initial automatic detection of stimuli often operates at a non-conscious level. However, whether fear generalization can occur when the cues are not perceived consciously remains unclear. The current study investigated the neurocognitive mechanisms underlying fear conditioning and its non-conscious and conscious generalization using a backward masking paradigm, combined with analysis of event-related potentials from electroencephalographic recordings. Behaviorally, participants showed heightened shock expectancy in response to non-conscious perceived generalization stimuli compared to those perceived consciously. Nonetheless, participants could not consciously distinguish between danger and safe cues in non-conscious trials. Physiologically, danger cues evoked larger frontal N1 amplitudes than safety cues in non-conscious trials, suggesting enhanced attention vigilance towards danger cues in the early sensory processing stage. Meanwhile, when fear generalization was conscious, it was accompanied by a larger P2 amplitude, indicating attention orientation or stimulus evaluation. In addition, fear conditioning was associated with sustained discrimination on P2, P3, and LPP. These findings collectively suggest that non-conscious fear generalization occurs at the neural level, yet additional control conditions are required to confirm this phenomenon on the US expectancy. Thus, non-consciously fear generalization may represent a mechanism that could trigger automatic irrational fear, highlighting the need for further research to explore therapeutic targets in anxiety disorders.

Can I see myself there? How Black potential applicants use diversity cues to learn about graduate program climate.

In academia, showcasing diversity, equity, and inclusion (DEI) values has become increasingly prominent in efforts to recruit students and faculty with marginalized identities, yet little work has examined the empirical effects that such DEI practices and identity safety cues have on the perceptions of these institutions. In the present study, we examine the contextual factors that shape how Black science, technology, engineering, and mathematics (STEM) students learn and draw inferences about diversity and cultural climate in the graduate programs to which they consider applying. A sample of 217 Black participants with background in a STEM discipline viewed a mock academic department website which presented varied combinations of expressed diversity cues (diversity vs. neutral mission statement) and/or evidence-based diversity cues (racially diverse vs. all-White faculty). Participants reported perceptions of the department's DEI culture, their own perceived fit within the program, and belief of future personal success within that institution. Results indicated a significant main effect of evidence-based cue, in the form of faculty diversity, on all examined outcomes, with Black participants more positively assessing a program exhibiting this cue. An expressed cue, in the form of diversity statement, did not have significant effects. These results indicate that in higher education, as in other settings, evidence-based cues may be more effective means to cue identity safety. This study provides a foundation for future research to help guide efforts of academic programs seeking to create a welcoming and supportive climate for all potential applicants. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

The effects of parental presence on amygdala and mPFC activation during fear conditioning: An exploratory study.

Learning safe versus dangerous cues is crucial for survival. During development, parents can influence fear learning by buffering their children's stress response and increasing exploration of potentially aversive stimuli. Rodent findings suggest that these behavioral effects are mediated through parental presence modulation of the amygdala and medial prefrontal cortex (mPFC). Here, we investigated whether similar parental modulation of amygdala and mPFC during fear learning occurs in humans. Using a within-subjects design, behavioral (final N=48, 6-17 years, mean=11.61, SD=2.84, 60% females/40% males) and neuroimaging data (final N=39, 6-17 years, mean=12.03, SD=2.98, 59% females/41% males) were acquired during a classical fear conditioning task, which included a CS+ followed by an aversive noise (US; 75% reinforcement rate) and a CS-. Conditioning occurred once in physical contact with the participant's parent and once alone (order counterbalanced). Region of interest analyses examined the unconditioned stress response by BOLD activation to the US (vs. implicit baseline) and learning by activation to the CS+ (vs. CS-). Results showed that during US presentation, parental presence reduced the centromedial amygdala activity, suggesting buffering of the unconditioned stress response. In response to learned stimuli, parental presence reduced mPFC activity to the CS+ (relative to the CS-), although this result did not survive multiple comparisons' correction. These preliminary findings indicate that parents modulate amygdala and mPFC activity during exposure to unconditioned and conditioned fear stimuli, potentially providing insight into the neural mechanisms by which parents act as a social buffer during fear learning. RESEARCH HIGHLIGHTS: This study used a within-participant experimental design to investigate how parental presence (vs. absence) affects youth's neural responses in a classical fear conditioning task. Parental presence reduced the youth's centromedial amygdala activation to the unconditioned stimulus (US), suggesting parental buffering of the neural unconditioned response (UR). Parental presence reduced the youth's mPFC activation to a conditioned threat cue (CS+) compared to a safety cue (CS-), suggesting possible parental modulation of fear learning.

Distributed neural representations of conditioned threat in the human brain

Detecting and responding to threat engages several neural nodes including the amygdala, hippocampus, insular cortex, and medial prefrontal cortices. Recent propositions call for the integration of more distributed neural nodes that process sensory and cognitive facets related to threat. Integrative, sensitive, and reproducible distributed neural decoders for the detection and response to threat and safety have yet to be established. We combine functional MRI data across varying threat conditioning and negative affect paradigms from 1465 participants with multivariate pattern analysis to investigate distributed neural representations of threat and safety. The trained decoders sensitively and specifically distinguish between threat and safety cues across multiple datasets. We further show that many neural nodes dynamically shift representations between threat and safety. Our results establish reproducible decoders that integrate neural circuits, merging the well-characterized ‘threat circuit’ with sensory and cognitive nodes, discriminating threat from safety regardless of experimental designs or data acquisition parameters.

Se Habla Español: The role of ethnic centrality in the effect of providing Spanish-language services in health clinics among Latinx Americans.

The present work experimentally examines whether a Spanish-speaking healthcare provider (an identity safety cue) increases the anticipated quality of care and healthcare utilization intentions of Latinx Americans (N = 180) and whether this effect is moderated by ethnic centrality. We find that providing Spanish-language services, versus not, on a healthcare facility's webpage significantly increases both anticipated quality of care and healthcare utilization intentions-but only for Latinx Americans who perceive their ethnicity as highly central to their self-concept. Likewise, we find that anticipated quality of care mediates the effect that identity safety cues have on healthcare utilization intentions only for Latinx Americans high on ethnic centrality. These findings demonstrate that members of minoritized ethnic groups shown to be the most susceptible to experiencing concerns of discrimination (people high on ethnic centrality) are also the most likely to benefit from identity safety cues that are designed to mitigate these very concerns.

HIV Interacts with Posttraumatic Stress Disorder to Impact Fear Psychophysiology in Trauma-Exposed Black Women.

The prevalence of posttraumatic stress disorder (PTSD) among people living with HIV (PLWH) is higher than in the general population and can impact health behaviors. The influence of HIV on PTSD psychophysiology requires further investigation due to implications for the treatment of PTSD in PLWH. Utilizing fear-potentiated startle (FPS), we aimed to interrogate the influence of PTSD and HIV on fear responses. Women (18-65 years of age) recruited from the Women's Interagency HIV Study in Atlanta, GA (n = 70, 26 without HIV and 44 with HIV), provided informed consent and completed a semistructured interview to assess trauma exposure and PTSD symptom severity. Participants also underwent an FPS paradigm to assess fear acquisition and extinction: Psychophysiological indices that measure how individuals learn new fear and then subsequently attempt to suppress this fear. Women with PTSD, who did not have HIV, exhibited a greater startle response compared to women without PTSD or HIV during late acquisition to both the danger cue, reinforced conditioned stimulus (CS+, p = 0.013)), and the safety cue, non-reinforced conditioned stimulus (CS-, p = 0.046)), whereas women living with HIV (WLH) and PTSD demonstrated blunted fear responses compared to women with PTSD only. During extinction, WLH comorbid with PTSD exhibited an increased fear response during the extinction period in comparison to all other groups (p = 0.023). Women without PTSD demonstrated a reduction in the fear response during extinction regardless of HIV status. Our findings indicate that HIV further modifies fear psychophysiology in WLH with comorbid PTSD, highlighting the importance of considering HIV status in conjunction with PTSD treatment.

Auditory aversive generalization learning prompts threat-specific changes in alpha-band activity.

Pairing a neutral stimulus with aversive outcomes prompts neurophysiological and autonomic changes in response to the conditioned stimulus (CS+), compared to cues that signal safety (CS-). One of these changes-selective amplitude reduction of parietal alpha-band oscillations-has been reliably linked to processing of visual CS+. It is, however, unclear to what extent auditory conditioned cues prompt similar changes, how these changes evolve as learning progresses, and how alpha reduction in the auditory domain generalizes to similar stimuli. To address these questions, 55 participants listened to three sine wave tones, with either the highest or lowest pitch (CS+) being associated with a noxious white noise burst. A threat-specific (CS+) reduction in occipital-parietal alpha-band power was observed similar to changes expected for visual stimuli. No evidence for aversive generalization to the tone most similar to the CS+ was observed in terms of alpha-band power changes, aversiveness ratings, or pupil dilation. By-trial analyses found that selective alpha-band changes continued to increase as aversive conditioning continued, beyond when participants reported awareness of the contingencies. The results support a theoretical model in which selective alpha power represents a cross-modal index of continuous aversive learning, accompanied by sustained sensory discrimination of conditioned threat from safety cues.

Validation of the Italian version of the Neuroception of Psychological Safety Scale (NPSS)

Research on the neuroscience of fear in both humans and non-humans has suggested that a lack of acquisition of safety cues might be a biological hallmark of posttraumatic stress disorder (PTSD). Danger perception, and in particular, feeling as one's own life is in danger, is thought to represent a major predictor of PTSD. Persistent danger perception is concurrently associated with a persistence of lack of safety. However, despite several research efforts, no validated psychometric tools exist regarding psychological safety as a unique core construct in the domain of a soothing-contentment system. By including social, compassionate, and bodily components, the Neuroception of Psychological Safety Scale (NPSS), neurophysiologically rooted in the polyvagal theory, aims to specifically assess psychological safety. Originally developed in English, we employed a rather large non clinical sample to validate our Italian translation of the NPSS (n = 338) and the scale was found to retain a three-factor structure. In light of its positive moderate correlations with the Unconditional Self-Kindness Scale (ρ = 0.376) and the Self-Compassion Scale-Short-Form (ρ = 0.481), good convergent validity and robust psychometric properties were shown by the NPSS. The Subjective Traumatic Outlook Questionnaire (ρ = −0.283) and the three subscales of the Body Perception Questionnaire-22—Body Awareness (ρ = −0.103), Supradiaphragmatic Reactivity (ρ = −0.234), and Body Awareness/Subdiaphragmatic Reactivity (ρ = −0.146)—were found to have weak negative correlations with the NPSS, which further demonstrated its good discriminant validity. Eventually, the NPSS was found to show good test-retest reliability (intraclass correlation coefficient = 0.922; three-week time interval), and its usage is fostered in clinical and research contexts where the evaluation of psychological safety is of relevance.

Transgender Patient Preferences When Discussing Gender in Health Care Settings

Transgender (trans) patients report frequent discriminatory and harmful experiences in health care settings; gender-affirming, competent health care improves trans individuals' health and well-being. To identify factors influencing trans patients' decision-making regarding sharing gender-related information with providers (clinicians, health care organizations, health care systems) and trans patient preferences for gender-related questions, as well as the subsequent impact on health care experiences. A qualitative, interpretivist phenomenological study was conducted via telephone or video (using Zoom) in English and Spanish from August 10 to September 11, 2020. Participants were recruited via trans-specific social media groups and email listservs. Interviews were transcribed verbatim and analyzed from October 2020 to January 2022 using thematic analysis by a majority trans research team. Semistructured interviews explored patient health care experiences and preferences. Participants included 27 trans and/or nonbinary adults (mean [SD] age, 30.9 [10.4] years; range, 21-69 years) from 13 US states. Four themes were identified: (1) impact of provider behaviors, (2) engaging in relational risk assessment, (3) receiving affirming vs medically competent care, and (4) "how are you going to fit [me] into your system?" The first theme reflected the impact of provider actions, including level of flexibility in care and interpersonal interactions, ability to explain medical relevance of gender-related questions, and preparedness to work with trans patients. Second, respondents weighed a variety of implicit or explicit safety cues when deciding whether and how to share information with providers. Third, participants spoke at length about affirming and medically competent care, noting that they have had to prioritize one over the other. Last, participants reported their needs often being at odds with health care system norms and standards of care. In this qualitative study of trans patient preferences when discussing gender-related information with providers, it was found that equitable, gender-affirming, and competent health care requires flexibility and responsiveness to patient preferences. It requires provider humility and engagement, as well as institutional policies that support competent and gender-affirming spaces. Future research could identify additional roles that providers, administrators, and systems can play in ensuring competent care for trans patients.

Anhedonia influences threat avoidance and relief: A conceptual replication

Active threat avoidance is an adaptive coping strategy but can evolve into maladaptive behavior patterns when it is disproportionate to an actual threat. While excessive and persistent avoidance, as often seen in anxiety-related disorders, have been investigated extensively, it is presently unclear under what circumstances insufficient avoidance might occur in the presence of a genuine threat. We hypothesized that anhedonia, the reduced ability to experience pleasure, might undermine the relief experience after successful threat avoidance and thus reduce future active avoidance responses. Using an established avoidance learning paradigm, we examined the relationship between anhedonia, relief, and active avoidance responses. Forty participants learned that two threat cues signaled electrical stimulation and they could click a button during cue presentations to prevent electrical stimulation from occurring. While clicking the button worked for one threat cue, it did not work for the other one. After several repetitions, button effectiveness was reversed. Another safety cue that never signaled electrical stimulation was presented intermixed with the two threat cues. Every time there was an omission of electrical stimulation, self-reported relief was measured. We found that participants who scored higher on anhedonia experienced weaker relief during all outcome omissions. Behaviorally, at the early stage of each phase, participants who scored higher on anhedonia executed fewer avoidance actions, specifically for the threat cue that signaled avoidable electrical stimulation. Relief induced by threat omission is a pleasant experience, which trait anhedonia seems to impair. This attenuation of relief might reduce the reinforcement of future adaptive avoidance behaviors.

Modulation of learning safety signals by acute stress: paraventricular thalamus and prefrontal inhibition

Distinguishing between cues predicting safety and danger is crucial for survival. Impaired learning of safety cues is a central characteristic of anxiety-related disorders. Despite recent advances in dissecting the neural circuitry underlying the formation and extinction of conditioned fear, the neuronal basis mediating safety learning remains elusive. Here, we showed that safety learning reduces the responses of paraventricular thalamus (PVT) neurons to safety cues, while activation of these neurons controls both the formation and expression of safety memory. Additionally, the PVT preferentially activates prefrontal cortex somatostatin interneurons (SOM-INs), which subsequently inhibit parvalbumin interneurons (PV-INs) to modulate safety memory. Importantly, we demonstrate that acute stress impairs the expression of safety learning, and this impairment can be mitigated when the PVT is inhibited, indicating PVT mediates the stress effect. Altogether, our findings provide insights into the mechanism by which acute stress modulates safety learning.

Changes in fear-associated learning task brain activation over the COVID-19 pandemic period: a preliminary longitudinal analysis.

The COVID-19 pandemic has had profound impacts on people worldwide. Previous studies have shown that fear learning, extinction, recall, and contextual information processing involve the activation of emotion and sensory brain systems, which can be modified. However, it remains unclear whether brain functions associated with these processes have been altered over the pandemic period. We compared pre- and peri-pandemic brain activation during a fear-associated learning task (FALT) using previously collected data. The participants were divided into two groups: the pandemic group (n = 16), who completed a baseline FALT before the pandemic and repeated the task during the pandemic, and the non-pandemic group (n = 77), who completed both sessions before the pandemic began. Compared with the non-pandemic group, the pandemic group exhibited significant decreases in brain activation from baseline to follow-up assessments, including activation in the brainstem during early fear learning, the posterior thalamus/hippocampus during late extinction, and the occipital pole during late recall phases for contextual processing. Furthermore, activations associated with retrieving safety cues were reduced in the posterior cingulate, premotor, and calcarine cortices during the early recall phase, and activations associated with retrieving dangerous cues decreased in the occipital pole during the late recall phase. Additionally, correlations between decreased activation and elevated posttraumatic stress symptoms were observed. These findings suggest that activations associated with processing low arousal contextual information, safety cues, and extinguished fear cues decreased during the pandemic. These changes in brain activation may have contributed to the increase in mental health disturbances observed during this time.