Fear extinction in traumatized civilians with posttraumatic stress disorder: relation to symptom severity

Sex differences in contextual fear conditioning and extinction after acute and chronic nicotine treatment

BACKGROUND

Chronic cigarette smokers report withdrawal symptomology, including affective dysfunction and cognitive deficits. While there are studies demonstrating sex specific withdrawal symptomology in nicotine-dependent individuals, literature examining the underlying biological mediators of this is scant and not in complete agreement. Therefore, in this study, we evaluated the sex specific effects of nicotine and withdrawal on contextual fear memory, a hippocampally dependent aspect of cognition that is disrupted in nicotine withdrawal.

METHODS

Male and female B6/129F1 mice (8-13 weeks old) were used in all experiments. For the acute nicotine experiment, mice received intraperitoneal saline or nicotine (0.5 mg/kg) prior to contextual fear conditioning and test. For the chronic nicotine experiment, mice received nicotine (18 mg/kg/day) or saline for 11 days, then underwent contextual fear conditioning and test. Following the test, mice underwent minipump removal to elicit withdrawal or sham surgery, followed by the fear extinction assay. Bulk cortical tissue was used to determine nicotinic acetylcholine receptor levels via single point [3H]Epibatidine binding assay. Gene expression levels in the dorsal and ventral hippocampus were quantified via RT-PCR.

RESULTS

We found that female mice had a stronger expression of contextual fear memory than their male counterparts. Further, following acute nicotine treatment, male, but not female, subjects demonstrated augmented contextual fear memory expression. In contrast, no significant effects of chronic nicotine treatment on fear conditioning were observed in either sex. When examining extinction of fear learning, we observed that female mice withdrawn from nicotine displayed impaired extinction learning, but no effect was observed in males. Nicotine withdrawal caused similar suppression of fosb, cfos, and bdnf, our proxy for neuronal activation and plasticity changes, in the dorsal and ventral hippocampus of both sexes. Additionally, we found that ventral hippocampus erbb4 expression, a gene implicated in smoking cessation outcomes, was elevated in both sexes following nicotine withdrawal.

CONCLUSIONS

Despite the similar impacts of nicotine withdrawal on gene expression levels, fosb, cfos, bdnf and erbb4 levels in the ventral hippocampus were predictive of delays in female extinction learning alone. This suggests sex specific dysfunction in hippocampal circuitry may contribute to female specific nicotine withdrawal induced deficits in extinction learning.

Dissociable contributions of the amygdala and ventral hippocampus to stress-induced changes in defensive behavior

Stress can have profound consequences on mental health. While much is known about the neural circuits supporting associative memories of stressful events, our understanding of the circuits underlying the non-associative impacts of stress, such as heightened stress sensitivity and anxiety-related behavior, is limited. Here, we demonstrate that the ventral hippocampus (vHC) and basolateral amygdala (BLA) support distinct non-associative behavioral changes following stress. Inhibiting stress-induced protein synthesis in the BLA blocked subsequent increases in stress sensitivity but not anxiety-related behaviors. Conversely, inhibiting stress-induced protein synthesis in the vHC blocked subsequent increases in anxiety-related behavior but not stress sensitivity. Inhibiting neuronal activity in the BLA and vHC during the assessment of stress sensitivity or anxiety-related behavior recapitulated these structures' dissociable contributions to defensive behavior. Lastly, blocking the associative memory of a stressor had no impact on stress-induced changes in anxiety-related behavior. These findings highlight that multiple memory systems support the long-lasting effects of stress.

Advancing the treatment of anxiety disorders in transition-age youth: a review of the therapeutic effects of unconscious exposure

BACKGROUND

The real-world effectiveness of exposure-based therapies for youth depends on the willingness and ability of young people to tolerate confronting their fears, which can be experienced as highly aversive and create problems with treatment engagement and acceptance. Recently, neuroscientific research on the nonconscious basis of fear has been translated into novel exposure interventions that bypass conscious processing of feared stimuli and that thus do not cause phobic youth to experience distress. We present a review of these unconscious exposure interventions.

METHODS

A PRISMA-based search yielded 20 controlled experiments based on three paradigms that tested if fear-related responses could be reduced without conscious awareness in highly phobic, transition-age youth: 14 randomized controlled trials (RCTs), 5 fMRI studies (1 was also an RCT), 4 psychophysiological studies (3 were also RCTs), and 1 ERP study. We conducted meta-analyses of outcomes where feasible.

RESULTS

Unconscious exposure interventions significantly (1) reduced avoidance behavior (range of Cohen's d = 0.51-0.95) and self-reported fear (d = 0.45-1.25) during in vivo exposure to the feared situation; (2) reduced neurobiological indicators of fear (d = 0.54-0.62) and concomitant physiological arousal (d = 0.55-0.64); (3) activated neural systems supporting fear regulation more strongly than visible exposure to the same stimuli (d = 1.2-1.5); (4) activated regions supporting fear regulation that mediated the reduction of avoidance behavior (d = 0.70); (5) evoked ERPs suggesting encoding of extinction memories (d = 2.13); and (6) had these effects without inducing autonomic arousal or subjective fear.

CONCLUSIONS

Unconscious exposure interventions significantly reduce a variety of symptomatic behaviors with mostly moderate effect sizes in transition-age youth with specific phobias. fMRI and physiological findings establish a neurophysiological basis for this efficacy, and suggest it occurs through extinction learning. Unconscious exposure was well tolerated, entirely unassociated with drop out, and is highly scalable for clinical practice. However, a number of limitations must be addressed to assess potential clinical impacts, including combining unconscious exposure with exposure therapy to boost treatment acceptance and efficacy.

Sex-specific role of high-fat diet and stress on behavior, energy metabolism, and the ventromedial hypothalamus

BACKGROUND

Scientific evidence highlights the influence of biological sex on the relationship between stress and metabolic dysfunctions. However, there is limited understanding of how diet and stress concurrently contribute to metabolic dysregulation in both males and females. Our study aimed to investigate the combined effects of high-fat diet (HFD) induced obesity and repeated stress on fear-related behaviors, metabolic, immune, and hypothalamic outcomes in male and female mice.

METHODS

To investigate this, we used a highly reliable rodent behavioral model that faithfully recapitulates key aspects of post-traumatic stress disorder (PTSD)-like fear. We subjected mice to footshock stressor followed by a weekly singular footshock stressor or no stressor for 14 weeks while on either an HFD or chow diet. At weeks 10 and 14 we conducted glucose tolerance and insulin sensitivity measurements. Additionally, we placed the mice in metabolic chambers to perform indirect calorimetric measurements. Finally, we collected brain and peripheral tissues for cellular analysis.

RESULTS

We observed that HFD-induced obesity disrupted fear memory extinction, increased glucose intolerance, and affected energy expenditure specifically in male mice. Conversely, female mice on HFD exhibited reduced respiratory exchange ratio (RER), and a significant defect in glucose tolerance only when subjected to repeated stress. Furthermore, the combination of repeated stress and HFD led to sex-specific alterations in proinflammatory markers and hematopoietic stem cells across various peripheral metabolic tissues. Single-nuclei RNA sequencing (snRNAseq) analysis of the ventromedial hypothalamus (VMH) revealed microglial activation in female mice on HFD, while male mice on HFD exhibited astrocytic activation under repeated stress.

CONCLUSIONS

Overall, our findings provide insights into complex interplay between repeated stress, high-fat diet regimen, and their cumulative effects on health, including their potential contribution to the development of PTSD-like stress and metabolic dysfunctions, emphasizing the need for further research to fully understand these interconnected pathways and their implications for health.

Acupuncture for Combat-Related Posttraumatic Stress Disorder: A Randomized Clinical Trial

Importance

Current interventions for posttraumatic stress disorder (PTSD) are efficacious, yet effectiveness may be limited by adverse effects and high withdrawal rates. Acupuncture is an emerging intervention with positive preliminary data for PTSD.

Objective

To compare verum acupuncture with sham acupuncture (minimal needling) on clinical and physiological outcomes.

Design, Setting, and Participants

This was a 2-arm, parallel-group, prospective blinded randomized clinical trial hypothesizing superiority of verum to sham acupuncture. The study was conducted at a single outpatient-based site, the Tibor Rubin VA Medical Center in Long Beach, California, with recruitment from April 2018 to May 2022, followed by a 15-week treatment period. Following exclusion for characteristics that are known PTSD treatment confounds, might affect biological assessment, indicate past nonadherence or treatment resistance, or indicate risk of harm, 93 treatment-seeking combat veterans with PTSD aged 18 to 55 years were allocated to group by adaptive randomization and 71 participants completed the intervention protocols.

Interventions

Verum and sham were provided as 1-hour sessions, twice weekly, and participants were given 15 weeks to complete up to 24 sessions.

Main Outcomes and Measures

The primary outcome was pretreatment to posttreatment change in PTSD symptom severity on the Clinician-Administered PTSD Scale-5 (CAPS-5). The secondary outcome was pretreatment to posttreatment change in fear-conditioned extinction, assessed by fear-potentiated startle response. Outcomes were assessed at pretreatment, midtreatment, and posttreatment. General linear models comparing within- and between-group were analyzed in both intention-to-treat (ITT) and treatment-completed models.

Results

A total of 85 male and 8 female veterans (mean [SD] age, 39.2 [8.5] years) were randomized. There was a large treatment effect of verum (Cohen d, 1.17), a moderate effect of sham (d, 0.67), and a moderate between-group effect favoring verum (mean [SD] Δ, 7.1 [11.8]; t90 = 2.87, d, 0.63; P = .005) in the intention-to-treat analysis. The effect pattern was similar in the treatment-completed analysis: verum d, 1.53; sham d, 0.86; between-group mean (SD) Δ, 7.4 (11.7); t69 = 2.64; d, 0.63; P = .01). There was a significant pretreatment to posttreatment reduction of fear-potentiated startle during extinction (ie, better fear extinction) in the verum but not the sham group and a significant correlation (r = 0.31) between symptom reduction and fear extinction. Withdrawal rates were low.

Conclusions and Relevance

The acupuncture intervention used in this study was clinically efficacious and favorably affected the psychobiology of PTSD in combat veterans. These data build on extant literature and suggest that clinical implementation of acupuncture for PTSD, along with further research about comparative efficacy, durability, and mechanisms of effects, is warranted.

Trial Registration

ClinicalTrials.gov Identifier: NCT02869646.

Basal forebrain cholinergic systems as circuits through which traumatic stress disrupts emotional memory regulation

Contextual and spatial systems facilitate changes in emotional memory regulation brought on by traumatic stress. Cholinergic basal forebrain (chBF) neurons provide input to contextual/spatial systems and although chBF neurons are important for emotional memory, it is unknown how they contribute to the traumatic stress effects on emotional memory. Clusters of chBF neurons that project to the prefrontal cortex (PFC) modulate fear conditioned suppression and passive avoidance, while clusters of chBF neurons that project to the hippocampus (Hipp) and PFC (i.e. cholinergic medial septum and diagonal bands of Broca (chMS/DBB neurons) are critical for fear extinction. Interestingly, neither Hipp nor PFC projecting chMS/DBB neurons are critical for fear extinction. The retrosplenial cortex (RSC) is a contextual/spatial memory system that receives input from chMS/DBB neurons, but whether this chMS/DBB-RSC circuit facilitates traumatic stress effects on emotional memory remain unexplored. Traumatic stress leads to neuroinflammation and the buildup of reactive oxygen species. These two molecular processes may converge to disrupt chBF circuits enhancing the impact of traumatic stress on emotional memory.

Psilocybin analog 4-OH-DiPT enhances fear extinction and GABAergic inhibition of principal neurons in the basolateral amygdala

Psychedelics such as psilocybin show great promise for the treatment of depression and PTSD, but their long duration of action poses practical limitations for patient access. 4-OH-DiPT is a fast-acting and shorter-lasting derivative of psilocybin. Here we characterized the pharmacological profile of 4-OH-DiPT and examined its impact on fear extinction learning as well as a potential mechanism of action. First, we profiled 4-OH-DiPT at all 12 human 5-HT GPCRs. 4-OH-DiPT showed strongest agonist activity at all three 5-HT2A/2B/2C receptors with near full agonist activity at 5-HT2A. Notably, 4-OH-DiPT had comparable activity at mouse and human 5-HT2A/2B/2C receptors. In a fear extinction paradigm, 4-OH-DiPT significantly reduced freezing responses to conditioned cues in a dose-dependent manner with a greater potency in female mice than male mice. Female mice that received 4-OH-DiPT before extinction training had reduced avoidance behaviors several days later in the light dark box, elevated plus maze and novelty-suppressed feeding test compared to controls, while male mice did not show significant differences. 4-OH-DiPT produced robust increases in spontaneous inhibitory postsynaptic currents (sIPSCs) in basolateral amygdala (BLA) principal neurons and action potential firing in BLA interneurons in a 5-HT2A-dependent manner. RNAscope demonstrates that Htr2a mRNA is expressed predominantly in BLA GABA interneurons, Htr2c mRNA is expressed in both GABA interneurons and principal neurons, while Htr2b mRNA is absent in the BLA. Our findings suggest that 4-OH-DiPT activates BLA interneurons via the 5-HT2A receptor to enhance GABAergic inhibition of BLA principal neurons, which provides a potential mechanism for suppressing learned fear.

Neigh G, Jovanovic T, Michopoulos V. HIV Interacts with Posttraumatic Stress Disorder to Impact Fear Psychophysiology in Trauma-Exposed Black Women

Background

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.

Objective

Utilizing fear-potentiated startle (FPS), we aimed to interrogate the influence of PTSD and HIV on fear responses.

Materials and Methods

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.

Results

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.

Conclusion

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.

Unconditioned response to a naturally aversive stimulus is associated with sensitized defensive responding and self-reported fearful traits in a PTSD sample

Unconditioned responding (UCR) to a naturally aversive stimulus is associated with defensive responding to a conditioned threat cue (CS+) and a conditioned safety cue (CS-) in trauma-exposed individuals during fear acquisition. However, the relationships of UCR with defensive responses during extinction training, posttraumatic stress disorder (PTSD) symptom severity, and fearful traits in trauma-exposed individuals are not known. In a sample of 100 trauma-exposed adults with a continuum of PTSD severity, we recorded startle responses and skin conductance responses (SCR) during fear acquisition and extinction training using a 140 psi, 250-ms air blast to the larynx as the unconditioned stimulus. We explored dimensional associations of two different measures of UCR (unconditioned startle and unconditioned SCR) with conditioned defensive responding to CS+ and CS-, conditioned fear (CS+ minus CS-), PTSD symptom severity, and a measure of fearful traits (composite of fear survey schedule, anxiety sensitivity index, and Connor-Davidson resilience scale). Unconditioned startle was positively associated with startle potentiation to the threat cue and the safety cue across both learning phases (CS+ Acquisition, CS- Acquisition, CS+ Extinction Training, CS- Extinction Training) and with fearful traits. Unconditioned SCR was positively associated with SCR to the CS+ and CS- and SCR difference score during Acquisition. Neither type of UCR was associated with PTSD symptom severity. Our findings suggest that UCR, particularly unconditioned startle to a naturally aversive stimulus, may inform research on biomarkers and treatment targets for symptoms of pervasive and persistent fear in trauma-exposed individuals.

A network approach to posttraumatic stress disorder: Comparing interview and self-report networks

OBJECTIVE

Trauma-related fear (e.g., reexperiencing), impaired reward (e.g., anhedonia), and interpersonal (e.g., detachment) processes may be functionally intertwined, giving rise to chronic psychopathology after a trauma. Network analyses can help pinpoint symptom drivers and treatment targets, but studies examining posttraumatic stress disorder (PTSD) treatment-seeking individuals are lacking.

METHOD

Treatment-seeking adults with primary PTSD (N = 350) completed interview and self-report measures of PTSD severity (PSS-I; PSS-SR). Self-report and interview-based networks were estimated and compared.

RESULTS

Both networks suggested distinct but interconnected communities of reexperiencing and dysphoric symptoms (e.g., interpersonal detachment, numbing). Centrality profiles were strongly associated across networks (rs = .71), with cued reexperiencing and interpersonal detachment showing strong centrality. Self-reported symptoms were more interconnected, suggesting lower specificity.

CONCLUSIONS

For those seeking treatment, interrelated fear and interpersonal processes may drive functional impairment in PTSD, and interview-based networks may help better delineate influential symptoms. Therapeutically, targeting cued reexperiencing and interpersonal detachment may facilitate broader symptom decreases. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

The interaction of Synapsin 2a and Synaptogyrin-3 regulates fear extinction in mice

The mechanisms behind a lack of efficient fear extinction in some individuals are unclear. Here, by employing a principal components analysis-based approach, we differentiated the mice into extinction-resistant and susceptible groups. We determined that elevated synapsin 2a (Syn2a) in the infralimbic cortex (IL) to basolateral amygdala (BLA) circuit disrupted presynaptic orchestration, leading to an excitatory/inhibitory imbalance in the BLA region and causing extinction resistance. Overexpression or silencing of Syn2a levels in IL neurons replicated or alleviated behavioral, electrophysiological, and biochemical phenotypes in resistant mice. We further identified that the proline-rich domain H in the C-terminus of Syn2a was indispensable for the interaction with synaptogyrin-3 (Syngr3) and demonstrated that disrupting this interaction restored extinction impairments. Molecular docking revealed that ritonavir, an FDA-approved HIV drug, could disrupt Syn2a-Syngr3 binding and rescue fear extinction behavior in Syn2a-elevated mice. In summary, the aberrant elevation of Syn2a expression and its interaction with Syngr3 at the presynaptic site were crucial in fear extinction resistance, suggesting a potential therapeutic avenue for related disorders.

The neural circuits and molecular mechanisms underlying fear dysregulation in posttraumatic stress disorder

Post-traumatic stress disorder (PTSD) is a stress-associated complex and debilitating psychiatric disorder due to an imbalance of neurotransmitters in response to traumatic events or fear. PTSD is characterized by re-experiencing, avoidance behavior, hyperarousal, negative emotions, insomnia, personality changes, and memory problems following exposure to severe trauma. However, the biological mechanisms and symptomatology underlying this disorder are still largely unknown or poorly understood. Considerable evidence shows that PTSD results from a dysfunction in highly conserved brain systems involved in regulating stress, anxiety, fear, and reward circuitry. This review provides a contemporary update about PTSD, including new data from the clinical and preclinical literature on stress, PTSD, and fear memory consolidation and extinction processes. First, we present an overview of well-established laboratory models of PTSD and discuss their clinical translational value for finding various treatments for PTSD. We then highlight the research progress on the neural circuits of fear and extinction-related behavior, including the prefrontal cortex, hippocampus, and amygdala. We further describe different molecular mechanisms, including GABAergic, glutamatergic, cholinergic, and neurotropic signaling, responsible for the structural and functional changes during fear acquisition and fear extinction processes in PTSD.

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

Background

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.

Methods

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.

Results

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.

Conclusion

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.

Sexually dimorphic role of diet and stress on behavior, energy metabolism, and the ventromedial hypothalamus

Scientific evidence underscores the influence of biological sex on the interplay between stress and metabolic dysfunctions. However, there is limited understanding of how diet and stress jointly contribute to metabolic dysregulation in both males and females. To address this gap, our study aimed to investigate the combined effects of a high-fat diet (HFD) and repeated footshock stress on fear-related behaviors and metabolic outcomes in male and female mice. Using a robust rodent model that recapitulates key aspects of post-traumatic stress disorder (PTSD), we subjected mice to footshock stressor followed by weekly reminder footshock stressor or no stressor for 14 weeks while on either an HFD or chow diet. Our findings revealed that HFD impaired fear memory extinction in male mice that received initial stressor but not in female mice. Blood glucose levels were influenced by both diet and sex, with HFD-fed female mice displaying elevated levels that returned to baseline in the absence of stress, a pattern not observed in male mice. Male mice on HFD exhibited higher energy expenditure, while HFD-fed female mice showed a decreased respiratory exchange ratio (RER). Sex-specific alterations in pro-inflammatory markers and abundance of hematopoietic stem cells were observed in chronically stressed mice on an HFD in different peripheral tissues, indicating the manifestation of distinct comorbid disorders. Single-nuclei RNA sequencing of the ventromedial hypothalamus from stressed mice on an HFD provided insights into sex-specific glial cell activation and cell-type-specific transcriptomic changes. In conclusion, our study offers a comprehensive understanding of the intricate interactions between stress, diet, sex, and various physiological and behavioral outcomes, shedding light on a potential brain region coordinating these interactions.

Time-course analysis of frontal gene expression profiles in the rat model of posttraumatic stress disorder and a comparison with the conditioned fear model

Posttraumatic stress disorder (PTSD) is a complex disorder that involves physiological, emotional, and cognitive dysregulation that may occur after exposure to a life-threatening event. In contrast with the condition of learned fear with resilience to extinction, abnormal fear with impaired fear extinction and exaggeration are considered crucial factors for the pathological development of PTSD. The prefrontal cortex (mPFC) is considered a critical region of top-down control in fear regulation, which involves the modulation of fear expression and extinction. The pathological course of PTSD is usually chronic and persistent; a number of studies have indicated temporal progression in gene expression and phenotypes may be involved in PTSD pathology. In the current study, we use a well-established modified single-prolonged stress (SPS&FS) rat model to feature PTSD-like phenotypes and compared it with a footshock fear conditioning model (FS model); we collected the frontal tissue after extreme stress exposure or fear conditioning and extracted RNA for transcriptome-level gene sequencing. We compared the genetic profiling of the mPFC at early (<2 h after solely FS or SPS&FS exposure) and late (7 days after solely FS or SPS&FS exposure) stages in these two models. First, we identified temporal differences in the expressional patterns between these two models and found pathways such as protein synthesis factor eukaryotic initiation factor 2 (EIF2), transcription factor NF-E2-related factor 2 (NRF2)-mediated oxidative stress response, and acute phase responding signaling enriched in the early stage in both models with significant p-values. Furthermore, in the late stage, the sirtuin signaling pathway was enriched in both models; other pathways such as STAT3, cAMP, lipid metabolism, Gα signaling, and increased fear were especially enriched in the late stage of the SPS&FS model. However, pathways such as VDR/RXR, GP6, and PPAR signaling were activated significantly in the FS model's late stage. Last, the network analysis revealed the temporal dynamics of psychological disorder, the endocrine system, and also genes related to increased fear in the two models. This study could help elucidate the genetic temporal alteration and stage-specific pathways in these two models, as well as a better understanding of the transcriptome-level differences between them.

Association between perimenopausal age and greater posttraumatic stress disorder and depression symptoms in trauma-exposed women

OBJECTIVE

This study aimed to determine the relationship between stages of the menopause transition (premenopausal, perimenopausal, and postmenopausal) on symptoms of posttraumatic stress disorder (PTSD) and depression in trauma-exposed women.

METHODS

A cross-sectional study conducted between 2005 and 2017 recruited and enrolled an urban community sample (n = 6,093) from nonpsychiatric medical clinic waiting rooms of Grady Memorial Hospital, a public safety net hospital in Atlanta, Georgia. Participants were female, 18 to 65 years old, and predominantly Black/African American.

RESULTS

Of the 6,093 participants, 93.8% were Black/African American, 2.5% were White, and 3.8% were of all other races (Hispanic/Latino, Asian, multiracial). Participants younger than 40 years were categorized as premenopausal (n = 3,166), between 40 and 55 years of age were categorized as perimenopausal (n = 2,127), and older than 55 years were categorized as postmenopausal (n = 790). Menopause status was associated with total PTSD symptom severity ( F2,5416 = 9.61, P < 0.001), symptom severity within all three PTSD symptom clusters (avoidance/numbing symptoms: F2,5416 = 7.10, P < 0.001; intrusive symptoms: F2,5416 = 7.04, P < 0.001; hyperarousal symptoms: F2,5409 = 8.31, P < 0.001), and depression symptom severity ( F2,5148 = 11.4, P < 0.001). Compared with both premenopausal and postmenopausal women, perimenopausal women reported significantly worse total PTSD symptoms, symptoms in the hyperarousal cluster, and depressive symptoms.

CONCLUSIONS

The current cross-sectional data show that symptoms of PTSD and depression in women are associated with reproductive age, such that perimenopausal women show higher symptom severity than premenopausal and postmenopausal women. Future longitudinal studies can reveal how changes in hormones over the course of the menopause transition impact the symptoms, neurobiology, and psychophysiology of PTSD.

Blunted Glucocorticoid Responsiveness to Stress Causes Behavioral and Biological Alterations That Lead to Posttraumatic Stress Disorder Vulnerability

BACKGROUND

Understanding why only a subset of trauma-exposed individuals develop posttraumatic stress disorder is critical for advancing clinical strategies. A few behavioral (deficits in fear extinction) and biological (blunted glucocorticoid levels, small hippocampal size, and rapid-eye-movement sleep [REMS] disturbances) traits have been identified as potential vulnerability factors. However, whether and to what extent these traits are interrelated and whether one of them could causally engender the others are not known.

METHODS

In a genetically selected rat model of reduced corticosterone responsiveness to stress, we explored posttraumatic stress disorder-related biobehavioral traits using ex vivo magnetic resonance imaging, cued fear conditioning, and polysomnographic recordings combined with in vivo photometric measurements.

RESULTS

We showed that genetic selection for blunted glucocorticoid responsiveness led to a correlated multitrait response, including impaired fear extinction (observed in males but not in females), small hippocampal volume, and REMS disturbances, supporting their interrelatedness. Fear extinction deficits and concomitant disruptions in REMS could be normalized through postextinction corticosterone administration, causally implicating glucocorticoid deficiency in two core posttraumatic stress disorder-related risk factors and manifestations. Furthermore, reduced REMS was accompanied by higher norepinephrine levels in the hippocampal dentate gyrus that were also reversed by postextinction corticosterone treatment.

CONCLUSIONS

Our results indicate a predominant role for glucocorticoid deficiency over the contribution of reduced hippocampal volume in engendering both REMS alterations and associated deficits in fear extinction consolidation, and they causally implicate blunted glucocorticoids in sustaining neurophysiological disturbances that lead to fear extinction deficits.

Introducing the Fear Learning and Anxiety Response (FLARe) app and web portal for the remote delivery of fear conditioning experiments

Experimental paradigms measuring key psychological constructs can enhance our understanding of mechanisms underlying human psychological well-being and mental health. Delivering such paradigms remotely affords opportunities to reach larger, more representative samples than is typically possible with in-person research. The efficiency gained from remote delivery makes it easier to test replication of previously established effects in well-powered samples. There are several challenges to the successful development and delivery of remote experimental paradigms, including use of an appropriate delivery platform, identifying feasible outcome measures, and metrics of participant compliance. In this paper, we present FLARe (Fear Learning and Anxiety Response), open-source software in the form of a smartphone app and web portal for the creation and delivery of remote fear conditioning experiments. We describe the benefits and challenges associated with the creation of a remote delivery platform for fear conditioning, before presenting in detail the resultant software suite, and one instance of deploying this using the FLARe Research infrastructure. We provide examples of the application of FLARe to several research questions which illustrate the benefits of the remote approach to experiment delivery. The FLARe smartphone app and web portal are available for use by other researchers and have been designed to be user-friendly and intuitive. We hope that FLARe will be a useful tool for those interested in conducting well-powered fear conditioning studies to inform our understanding of the development and treatment of anxiety disorders.

MicroRNA expression profiles of stress susceptibility and resilience in the prelimbic and infralimbic cortex of rats after single prolonged stress

The experience of traumatic stress can engender lasting memories associated with the trauma, often resulting in post-traumatic stress disorder (PTSD). However, only a minority of individuals develop PTSD symptoms upon exposure. The neurobiological mechanisms underlying the pathology of PTSD are poorly understood. Utilizing a rat model of PTSD, the Single Prolonged Stress (SPS) paradigm, we were able to differentiate between resilient and susceptible individuals. Fourteen days after the SPS exposure, we conducted the behavioral analyses using Elevated Plus Maze (EPM) and Open Field (OF) tests to identify male rats as trauma resilient or susceptible. We focused on the microRNA (miRNA) profiles of the infralimbic (IL) and prelimbic (PL) cortical regions, known to be crucial in regulating the stress response. Our investigation of stressed rats exposed to the SPS procedure yielded divergent response, and differential expression microRNAs (DEmiRs) analysis indicated significant differences in the IL and PL transcriptional response. In the IL cortex, the GO analysis revealed enriched GO terms in the resilient versus control comparison, specifically related to mitogen-activated protein kinase and MAP kinase signaling pathways for their molecular functions as well as cytosol and nucleoplasm for the biological process. In the susceptible versus resilient comparison, the changes in molecular functions were only manifested in the functions of regulation of transcription involved in the G1/S transition of the mitotic cell cycle and skeletal muscle satellite cell activation. However, no enriched GO terms were found in the susceptible versus control comparison. In the PL cortex, results indicated that the DEmiRs were enriched exclusively in the cellular component level of the endoplasmic reticulum lumen in the comparison between resilient and control rats. Overall, our study utilized an animal model of PTSD to investigate the potential correlation between stress-induced behavioral dysfunction and variations in miRNA expression. The aforementioned discoveries have the potential to pave the way for novel therapeutic approaches for PTSD, which could involve the targeted regulation of transcriptome expression.

Predicting Fear Extinction in Posttraumatic Stress Disorder

Fear extinction is the basis of exposure therapies for posttraumatic stress disorder (PTSD), but half of patients do not improve. Predicting fear extinction in individuals with PTSD may inform personalized exposure therapy development. The participants were 125 trauma-exposed adults (96 female) with a range of PTSD symptoms. Electromyography, electrocardiogram, and skin conductance were recorded at baseline, during dark-enhanced startle, and during fear conditioning and extinction. Using a cross-validated, hold-out sample prediction approach, three penalized regressions and conventional ordinary least squares were trained to predict fear-potentiated startle during extinction using 50 predictor variables (5 clinical, 24 self-reported, and 21 physiological). The predictors, selected by penalized regression algorithms, were included in multivariable regression analyses, while univariate regressions assessed individual predictors. All the penalized regressions outperformed OLS in prediction accuracy and generalizability, as indexed by the lower mean squared error in the training and holdout subsamples. During early extinction, the consistent predictors across all the modeling approaches included dark-enhanced startle, the depersonalization and derealization subscale of the dissociative experiences scale, and the PTSD hyperarousal symptom score. These findings offer novel insights into the modeling approaches and patient characteristics that may reliably predict fear extinction in PTSD. Penalized regression shows promise for identifying symptom-related variables to enhance the predictive modeling accuracy in clinical research.

Structural inequities contribute to racial/ethnic differences in neurophysiological tone, but not threat reactivity, after trauma exposure

Considerable racial/ethnic disparities persist in exposure to life stressors and socioeconomic resources that can directly affect threat neurocircuitry, particularly the amygdala, that partially mediates susceptibility to adverse posttraumatic outcomes. Limited work to date, however, has investigated potential racial/ethnic variability in amygdala reactivity or connectivity that may in turn be related to outcomes such as post-traumatic stress disorder (PTSD). Participants from the AURORA study (n = 283), a multisite longitudinal study of trauma outcomes, completed functional magnetic resonance imaging and psychophysiology within approximately two-weeks of trauma exposure. Seed-based amygdala connectivity and amygdala reactivity during passive viewing of fearful and neutral faces were assessed during fMRI. Physiological activity was assessed during Pavlovian threat conditioning. Participants also reported the severity of posttraumatic symptoms 3 and 6 months after trauma. Black individuals showed lower baseline skin conductance levels and startle compared to White individuals, but no differences were observed in physiological reactions to threat. Further, Hispanic and Black participants showed greater amygdala connectivity to regions including the dorsolateral prefrontal cortex (PFC), dorsal anterior cingulate cortex, insula, and cerebellum compared to White participants. No differences were observed in amygdala reactivity to threat. Amygdala connectivity was associated with 3-month PTSD symptoms, but the associations differed by racial/ethnic group and were partly driven by group differences in structural inequities. The present findings suggest variability in tonic neurophysiological arousal in the early aftermath of trauma between racial/ethnic groups, driven by structural inequality, impacts neural processes that mediate susceptibility to later PTSD symptoms.

From recent advances in underlying neurocircuitry of fear and anxiety to promising pharmacotherapies for PTSD: The saga of heart, sex and the developing brain

Available pharmacotherapies for anxiety disorders and post-traumatic stress-disorder (PTSD) have limited efficacy, but no new anxiolytic drug has been approved for treatment since the 1980s. In this issue of Neuropharmacology on "Fear, anxiety and PTSD: from cellular mechanisms to translational approaches", we review the currently recommended pharmacotherapy for PTSD and discuss promising pharmacotherapies being revisited or newly developed. Novel strategies for pharmaceuticals in PTSD treatment include the use of serotonergic psychedelics as low-dose adjunct therapies combined with psychotherapy. We also discuss the use of glucocorticoids targeting the temporal window shortly following trauma exposure to interfere with fear memory consolidation. Although many factors have impeded progress in pharmacotherapy development for anxiety disorders and PTSD, we highlight three: (1) the sparsity of preclinical studies investigating the neurobiology of fear processing in female animal models despite the higher prevalence of anxiety disorders in women, (2) the poor implementation of the knowledge of how stress affects fear circuitry development across the lifetime into clinical practice, and (3) our paucity of knowledge of canonical fear circuitry in adaptive vs. maladaptive fear processing. Finally, we emphasize the functional link between interoceptive signals and emotion regulation and discuss how these interoceptive signals may be an inroad into PTSD treatment, which is often accompanied by cardiovascular dysregulation. A better understanding of the neurobiological underpinnings of adaptive and maladaptive fear processing is critical for identifying risk factors that will spur the development of sex- and developmental trauma-specific interventions, ushering in a new era of precision medicine for anxiety disorders and PTSD.

Conscious knowledge of CS-UCS contingency information affects extinction retrieval of conditioned disgust responses: Findings from an online de novo disgust conditioning task

Objective

The present study aimed to establish and develop an online de novo conditioning paradigm for the measurement of conditioned disgust responses. We further explored the effects of explicit instructions about the CS-UCS contingency on extinction learning and retrieval of conditioned disgust responses.

Method

The study included a sample of 115 healthy participants. Geometric figures served as conditioned stimuli (CS) and disgust-evoking pictures as unconditioned stimuli (UCS). During disgust conditioning, the CS+ was paired with the UCS (66% reinforcement) and the CS- remained unpaired; during extinction and retrieval, no UCS was presented. Half of the participants (n = 54) received instructions prior to the disgust extinction stating that the UCS will not be presented anymore. 1-2 days or 7-8 days later participants performed a retrieval test. CS-UCS contingency, disgust and valence ratings were used as dependent measures.

Results

Successful acquisition of conditioned disgust response was observed on the level of CS-UCS contingency, disgust and valence ratings. While some decline in valence and disgust ratings during the extinction stage was observed, contingency instructions did not significantly affect extinction performance. Retrieval one week later revealed that contingency instructions increased the discrimination of the CSs.

Conclusions

Extinction of conditioned disgust responses is not affected by explicit knowledge of the CS-UCS contingencies. However, contingency instructions prior to extinction seem to have a detrimental effect on long-term extinction retrieval.

Peroxisome proliferator-activated receptor-α activation facilitates contextual fear extinction and modulates intrinsic excitability of dentate gyrus neurons

The dentate gyrus (DG) of the hippocampus encodes contextual information associated with fear, and cell activity in the DG is required for acquisition and extinction of contextual fear. However, the underlying molecular mechanisms are not fully understood. Here we show that mice deficient for peroxisome proliferator-activated receptor-α (PPARα) exhibited a slower rate of contextual fear extinction. Furthermore, selective deletion of PPARα in the DG attenuated, while activation of PPARα in the DG by local infusion of aspirin facilitated extinction of contextual fear. The intrinsic excitability of DG granule neurons was reduced by PPARα deficiency but increased by activation of PPARα with aspirin. Using RNA-Seq transcriptome we found that the transcription level of neuropeptide S receptor 1 (Npsr1) was tightly correlated with PPARα activation. Our results provide evidence that PPARα plays an important role in regulating DG neuronal excitability and contextual fear extinction.

Pre-Learning Stress That Is Temporally Removed from Acquisition Impairs Fear Learning

Few studies have examined the time-dependent effects of stress on fear learning. Previously, we found that stress immediately before fear conditioning enhanced fear learning. Here, we aimed to extend these findings by assessing the effects of stress 30 min prior to fear conditioning on fear learning and fear generalization. Two hundred and twenty-one healthy adults underwent stress (socially evaluated cold pressor test) or a control manipulation 30 min before completing differential fear conditioning in a fear-potentiated startle paradigm. One visual stimulus (CS+), but not another (CS-), was associated with an aversive airblast to the throat (US) during acquisition. The next day, participants were tested for their fear responses to the CS+, CS-, and several generalization stimuli. Stress impaired the acquisition of fear on Day 1 but had no significant impact on fear generalization. The stress-induced impairment of fear learning was particularly evident in participants who exhibited a robust cortisol response to the stressor. These findings are consistent with the notion that stress administered 30 min before learning impairs memory formation via corticosteroid-related mechanisms and may help us understand how fear memories are altered in stress-related psychological disorders.

The fear that remains: Associations between trauma, related psychopathology, and fear‐potentiated startle in youth resettled as refugees

Fear-potentiated startle (FPS) can be used to measure fear and safety learning-behaviors affected by trauma that may map onto posttraumatic stress disorder (PTSD). Therefore, FPS could be a candidate biomarker of trauma-related psychopathology and a potential identifier of trauma-exposed youth in need of focused treatment. We enrolled n = 71 (35 females, M_age  = 12.7 years) Syrian youth exposed to civilian war trauma. Eyeblink electromyogram (EMG) data from a differential conditioning FPS paradigm were obtained 2.5 years after resettlement. Youth provided self-report of trauma exposure (Harvard Trauma Questionnaire) and PTSD symptoms (UCLA PTSD Reaction Index). While FPS during conditioning was not associated with symptoms, associations with psychopathology emerged in fear extinction. Probable PTSD was associated with FPS in the last block of extinction, such that FPS to threat cue was significantly greater in the PTSD+ group compared to the PTSD- group at the end of extinction (F = 6.25, p = .015). As with adults, we observed a deficit in extinction learning but not fear conditioning in youth with PTSD. These results support the use of trauma-informed cognitive behavioral therapy based on the learning principles of extinction in youth with PTSD.

Therapeutic interventions impact brain function and promote post-traumatic growth in adults living with post-traumatic stress disorder: A systematic review and meta-analysis of functional magnetic resonance imaging studies

Introduction

The present systematic review and meta-analysis explores the impacts of cognitive processing therapy (CPT), eye movement desensitization and reprocessing (EMDR), and prolonged exposure (PE) therapy on neural activity underlying the phenomenon of post-traumatic growth for adult trauma survivors.

Methods

We utilized the following databases to conduct our systematic search: Boston College Libraries, PubMed, MEDLINE, and PsycINFO. Our initial search yielded 834 studies for initial screening. We implemented seven eligibility criteria to vet articles for full-text review. Twenty-nine studies remained for full-text review after our systematic review process was completed. Studies were subjected to several levels of analysis. First, pre-and post- test post-traumatic growth inventory (PTGI) scores were collected from all studies and analyzed through a forest plot using Hedges' g. Next, Montreal Neurological Institute (MNI) coordinates and t-scores were collected and analyzed using an Activation Likelihood Estimation (ALE) to measure brain function. T-scores and Hedges' g values were then analyzed using Pearson correlations to determine if there were any relationships between brain function and post-traumatic growth for each modality. Lastly, all studies were subjected to a bubble plot and Egger's test to assess risk of publication bias across the review sample.

Results

Forest plot results indicated that all three interventions had a robust effect on PTGI scores. ALE meta-analysis results indicated that EMDR exhibited the largest effect on brain function, with the R thalamus (t = 4.23, p < 0.001) showing robust activation, followed closely by the R precuneus (t = 4.19, p < 0.001). Pearson correlation results showed that EMDR demonstrated the strongest correlation between increased brain function and PTGI scores (r = 0.910, p < 0.001). Qualitative review of the bubble plot indicated no obvious traces of publication bias, which was corroborated by the results of the Egger's test (p = 0.127).

Discussion

Our systematic review and meta-analysis showed that CPT, EMDR, and PE each exhibited a robust effect on PTG impacts across the course of treatment. However, when looking closer at comparative analyses of neural activity (ALE) and PTGI scores (Pearson correlation), EMDR exhibited a more robust effect on PTG impacts and brain function than CPT and PE.

The Enduring Importance of Parenting: Caregiving Quality and Fear-Potentiated Startle in Emerging Adults With a Child Maltreatment History

Background: The transition to adulthood is a period of increased risk for emergent psychopathology; emerging adults with a childhood maltreatment history are at risk for poor outcomes. Method: Using a multi-measure, transdisciplinary, cross-sectional design, this study tested whether participant-reported positive parenting, a potential resilience-promoting factor, moderated the association between clinician-rated PTSD symptom severity and a transdiagnostic maladjustment biomarker, fear-potentiated startle (FPS), in a sample of 66 emerging adults (Myears = 18.83, SD = 0.89) with a maltreatment history. We hypothesized that characteristics of effective parenting would moderate the relation between PTSD symptoms and FPS. Results: Results indicated that elevated PTSD, as measured by the CAPS, was associated with a more severe startle reaction. The magnitude of the increase in startle reactivity was moderated by parenting such that those with more positive parenting (Accepting [relative to rejecting]: b = -0.42, p < .001; Psychologically-controlling [relative to autonomy-promoting]: b = 2.96, p = .004) had significantly less reactivity across the task at higher levels of PTSD symptoms. Conclusions: Emerging adults with childhood maltreatment histories, high levels of PTSD symptoms, and who perceive present-day high-quality caregiver support may cope better with novel stressors relative to youth lacking that support, potentially translating to better psychological outcomes.

Is Fear Extinction Impairment Central to Psychopathology?

As discussed in this chapter, there have been enormous advances in our understanding of how anxiety disorders develop, are maintained, and can be treated. Many of these advances have been the result of translational studies using fear conditioning and extinction models. Despite these successes, we recognize, as a field, that there are important limitations in the extent to which extinction can explain how anxiety disorders and behaviors remit. Clinically speaking, the outstanding challenge for treatment of anxiety disorders is to improve the current suboptimal success rates. Over the past 30 years, we have not improved our treatment success rates despite employing many pharmacological and pharmacological strategies. While extinction and related fear circuitry mechanisms most certainly appear to play a role in treatment of anxiety disorders, they are also apparently insufficient to fully accommodate the varied responses individuals exhibit with this treatment approach. Increasingly diverse and innovative approaches are needed that accommodate the multitude of change mechanisms involved in treating anxiety. However, this is not to suggest ignoring the key role that extinction and memory updating processes play in overcoming anxiety.

Are cognitive aspects of defense a core feature of anxiety and depression?

Anxiety and depression are highly prevalent behavior disorders, particularly in women. Recent preclinical work using animal models has been suboptimal in predicting the efficacy of drugs targeted at these conditions, suggesting a potential discrepancy between such models and the human disorders. Notably female animals tend to be equal to, or less responsive than, males in these tasks. A number of analyses suggest that mammalian defense patterns are complex: In addition to relatively discrete and immediate fight, flight, and freezing responses, a risk assessment pattern may occur in response to threat stimuli or situations with ambiguous elements. This pattern combines defensiveness with a number of cognition-linked behaviors such as sensory attention and orientation, approach, contact, and investigation of the potential threat. Studies measuring elements of this pattern suggest that female rats, and perhaps female mice, show higher levels than equivalent males. Higher female involvement may also occur in tasks involving learning/generalization/extinction of defensiveness to conditioned stimuli. Such findings are consonant with recent analyses of "female survival strategies" based on differential adaptiveness of cognitive components of defensiveness in females, due to the necessity of female care of offspring until they are independent. These data suggest the value of additional behavioral and functional analyses of cognitive aspects of defensive behavior; contributing to both an understanding of their underlying mechanisms, and providing more sensitive measures of drug responsivity for use with animal models.

Extinction-Based Exposure Therapies Using Virtual Reality

The focus of this chapter is an overview of integrating virtual reality (VR) technology within the context of exposure therapy for anxiety disorders, a gold standard treatment, with a focus on how VR can help facilitate extinction learning processes integral to these interventions. The chapter will include an overview of advantages of incorporating VR within exposure therapy, and benefits specifically within an inhibitory learning approach for extinction training. A review of the empirical literature on the effectiveness of VR exposure therapy for specific phobia and PTSD will be provided, as well as practical overview of how to effectively incorporate VR within exposure therapy.

Understanding Human Fear Extinction: Insights from Psychophysiology

The study of fear extinction has been driven largely by Pavlovian fear conditioning methods across the translational spectrum. The primary methods used to study these processes in humans have been recordings of skin conductance (historically termed galvanic skin response) and fear-potentiation of the acoustic startle reflex. As outlined in the following chapter, the combined corpus of this work has demonstrated the value of psychophysiology in better understanding the underlying neurobiology of extinction learning in healthy humans as well as those with psychopathologies. In addition, psychophysiological approaches, which allow for the preservation of methods between species, have shown their applicability to the assessment of wide-ranging treatment effects. The chapter concludes with potential trajectories for future study in this area.

Sex differences in the effect of subjective sleep on fear conditioning, extinction learning, and extinction recall in individuals with a range of PTSD symptom severity

Sleep has been found to play a key role in fear conditioning, extinction learning and extinction recall, and sleep disturbances are linked to many mental disorders including post-traumatic stress disorder (PTSD). Previous studies examining associations between sleep and fear or extinction processes primarily focused on objectively measured sleep architecture. Little research has so far focused on subjective sleep measures and particularly in clinical populations, which often experience subjectively poor sleep, including PTSD. Here we investigated whether subjective sleep disturbance, sleep onset latency, wake after sleep onset or sleep efficiency were related to fear conditioning, extinction learning or extinction recall in a large sample of individuals with a range of PTSD symptom severity (n = 248). Overall, we did not find that subjective sleep was associated with fear conditioning or extinction processes. However, exploratory analyses examining the moderating effect of sex found that shorter sleep onset latency and greater sleep efficiency were associated with improved extinction recall in women with higher PTSD symptom severity. This suggests that less time falling asleep and longer time asleep while in bed may be protective in highly symptomatic women against the commonly observed impaired extinction recall in PTSD. More studies are needed to explore sex-specific effects further.

Childhood Maltreatment in Females Is Associated with Enhanced Fear Acquisition and an Overgeneralization of Fear

Childhood maltreatment may alter fear neurocircuitry, which results in pathological anxiety and depression. One alteration of fear-related behaviors that has been observed in several psychiatric populations is an overgeneralization of fear. Thus, we examined the association between childhood maltreatment and fear generalization in a non-clinical sample of young adults. Two hundred and ninety-one participants underwent differential fear conditioning in a fear-potentiated startle paradigm. One visual stimulus (CS+), but not another (CS-), was associated with an aversive airblast to the throat (US) during acquisition. The next day, participants were tested for their fear responses to the CS+, CS-, and several generalization stimuli (GS) without the presence of the US. Participants also completed questionnaires that assessed symptoms of childhood maltreatment, anxiety, depression, and post-traumatic stress disorder (PTSD). Participants reporting high childhood maltreatment (n = 71; 23 males, 48 females) exhibited significantly greater anxiety, depression, and symptoms of PTSD than participants reporting low childhood maltreatment (n = 220; 133 males, 87 females). Females reporting high childhood maltreatment demonstrated significantly enhanced fear learning and greater fear generalization, based on their fear-potentiated startle responses. Our findings suggest that childhood maltreatment may sex-dependently influence the development of fear neurocircuitry and result in greater fear generalization in maltreated females.

Alterations of mitochondrial dynamics in serotonin transporter knockout rats: A possible role in the fear extinction recall mechanisms

Stress-related mental disorders encompass a plethora of pathologies that share the exposure to a negative environment as trigger for their development. The vulnerability to the effects of a negative environment is not equal to all but differs between individuals based on the genetic background makeup. Here, to study the molecular mechanisms potentially underlying increased threat anticipation, we employed an animal model showing this symptom (5-HTT knockout rats) which we exposed to Pavlovian fear conditioning (FC). We investigated the role of mitochondria, taking advantage of the recent evidence showing that the dynamic of these organelles is dysregulated after stress exposure. Behavioral experiments revealed that, during the second day of extinction of the FC paradigm, 5-HTT knockout (5-HTT-/-) animals showed a lack of fear extinction recall. From a mechanistic standpoint, we carried out our molecular analyses on the amygdala and prefrontal cortex, given their role in the management of the fear response due to their tight connection. We demonstrated that mitochondrial dynamics are impaired in the amygdala and prefrontal cortex of 5-HTT-/- rats. The dissection of the potential contributing factors revealed a critical role in the mechanisms regulating fission and fusion that are dysregulated in transgenic animals. Furthermore, mitochondrial oxidative phosphorylation, mitochondrial biogenesis, and the production of antioxidant enzymes were altered in these brain regions in 5-HTT-/- rats. In summary, our data suggest that increased extracellular 5-HT levels cause an unbalance of mitochondrial functionality that could contribute to the reduced extinction recall of 5-HTT-/- rats, pointing out the role of mitochondrial dynamics in the etiology of psychiatric disorders. Our findings, also, provide some interesting insights into the targeted development of drugs to treat such disorders.

A cross-sectional study on the mental health of patients with COVID-19 1 year after discharge in Huanggang, China

OBJECTIVE

This study is aimed to investigate the mental health status of COVID-19 survivors 1 year after discharge from hospital and reveal the related risk factors.

METHODS

From April 11 to May 11, 2021, 566 COVID-19 survivors in Huanggang city were recruited through their primary doctors. A total of 535 participants (94.5%) admitted to participate in the survey and completed the questionnaires. Five scales were applied including 7-Items Generalized Anxiety Disorder Scale, Patient Health Questionnaire-9, Impact of Event Scale-Revised, Pittsburgh Sleep Quality Index, and Fatigue Scale-14. The chi-square and the Fisher's exact test were used to evaluate the classification data, multivariate logistic regression was used to explore the related factors of sleep quality, fatigue, anxiety, depression, and post-traumatic stress disorder (PTSD).

RESULTS

One year after being discharged, of the 535 COVID-19 survivors, 252 (47.1%) had poor sleep quality; 157 (29.3%) had the symptoms of fatigue; 84 (15.7%),112 (20.9%), and 130 (24.3%) suffered from symptoms of anxiety, depression, and PTSD, respectively. The logistic regression analysis showed that history of chronic disease was risk factor for poor sleep quality (OR 2.501; 95% CI, 1.618-3.866), fatigue (OR 3.284; 95% CI 2.143-5.033), PTSD (OR 2.323; 95% CI 1.431-3.773) and depression (OR 1.950; 95% CI 1.106-3.436) in COVID-19 survivors. Smoking contributed to the poor sleep quality (OR 2.005; 95% CI 1.044-3.850), anxiety (OR 4.491; 95% CI 2.276-8.861) and depression (OR 5.459; 95% CI 2.651-11.239) in survivors. Drinking influenced fatigue (OR 2.783; 95% CI 1.331-5.819) and PTSD (OR 4.419; 95% CI 1.990-9.814) in survivors. Compared with college-educated survivors, survivors with high school education were at higher risk for poor sleep quality (OR 1.828; 95% CI 1.050-3.181) and PTSD (OR 2.521; 95% CI 1.316-4.830), and survivors with junior high school education were at higher risk for PTSD (OR 2.078; 95% CI 1.039-4.155). Compared with overweight survivors (BMI ≥ 23.0), survivors with normal BMI (18.5-22.9) (OR 0.600; 95% CI 0.405-0.889) were at lower risk for fatigue. While being housewife (OR 0.390; 95% CI 0.189-0.803) was protective factor for fatigue and having more family members was protective factor for PTSD (OR 0.404 95% CI 0.250-0.653) in survivors.

CONCLUSIONS

One year after infection, poor sleep quality, fatigue, anxiety, depression, and PTSD, still existed in a relatively high proportion of COVID-19 survivors. Chronic disease history was an independent risk factor for poor sleep quality, fatigue, depression, and PTSD. Participants with low education levels were more likely to have mental problems than the others. We should focus on the long-term psychological impact of COVID-19 on survivors, and the government should apply appropriate mental health services to offer psychiatric support.

The Efficacy of Psychedelic-Assisted Therapy in Managing Post-traumatic Stress Disorder (PTSD): A New Frontier?

Post-traumatic stress disorder (PTSD) is a significant public health concern for which existing therapies are only marginally effective. Indisputably, the primary line of treatment for PTSD is psychotherapy, according to current treatment guidelines. However, PTSD continues to be a chronic condition even after psychotherapy, with high psychiatric and medical illness rates. There is a dire need to search for new compounds and approaches for managing PTSD. The usage of psychedelic substances is a potential new method. This article reviews the efficacy of psychedelic-assisted therapy in treating PTSD and improving patient outcomes. It will examine current research on the topic and evaluate the benefits and drawbacks of different therapies. The current evidence for the use of four different types of psychedelics (3,4-methylenedioxymethamphetamine, ketamine, classical psychedelics, and cannabis) in the treatment of PTSD will be reviewed. It will also include an overview of the therapeutic justification, context of use, and level of evidence available for each drug. Several questions are formulated that could be studied in future research in order to gain a better understanding of the topic.

Randomized controlled experimental study of hydrocortisone and D-cycloserine effects on fear extinction in PTSD

Fear extinction underlies prolonged exposure, one of the most well-studied treatments for posttraumatic stress disorder (PTSD). There has been increased interest in exploring pharmacological agents to enhance fear extinction learning in humans and their potential as adjuncts to PE. The objective of such adjuncts is to augment the clinical impact of PE on the durability and magnitude of symptom reduction. In this study, we examined whether hydrocortisone (HC), a corticosteroid, and D-Cycloserine (DCS), an N-methyl-D-aspartate receptor partial agonist, enhance fear extinction learning and consolidation in individuals with PTSD. In a double-blind placebo-controlled 3-group experimental design, 90 individuals with full or subsyndromal PTSD underwent fear conditioning with stimuli that were paired (CS+) or unpaired (CS-) with shock. Extinction learning occurred 72 h later and extinction retention was tested one week after extinction. HC 25 mg, DCS 50 mg or placebo was administered one hour prior to extinction learning. During extinction learning, the DCS and HC groups showed a reduced differential CS+/CS- skin conductance response (SCR) compared to placebo (b = -0.19, CI = -0.01 to -37, p = 0.042 and b = -0.25, CI = -08 to -0.43, p = 0.005, respectively). A nonsignificant trend for a lower differential CS+/CS- SCR in the DCS group, compared to placebo, (b = -0.25, CI = 0.04 to -0.55, p = 0.089) was observed at retention testing, one week later. A single dose of HC and DCS facilitated fear extinction learning in participants with PTSD symptoms. While clinical implications have yet to be determined, our findings suggest that glucocorticoids and NMDA agonists hold promise for facilitating extinction learning in PTSD.

Revisiting sex differences in the acquisition and extinction of threat conditioning in humans

Findings pertaining to sex differences in the acquisition and extinction of threat conditioning, a paradigm widely used to study emotional homeostasis, remain inconsistent, particularly in humans. This inconsistency is likely due to multiple factors, one of which is sample size. Here, we pooled functional magnetic resonance imaging (fMRI) and skin conductance response (SCR) data from multiple studies in healthy humans to examine sex differences during threat conditioning, extinction learning, and extinction memory recall. We observed increased functional activation in males, relative to females, in multiple parietal and frontal (medial and lateral) cortical regions during acquisition of threat conditioning and extinction learning. Females mainly exhibited higher amygdala activation during extinction memory recall to the extinguished conditioned stimulus and also while responding to the unconditioned stimulus (presentation of the shock) during threat conditioning. Whole-brain functional connectivity analyses revealed that females showed increased connectivity across multiple networks including visual, ventral attention, and somatomotor networks during late extinction learning. At the psychophysiological level, a sex difference was only observed during shock delivery, with males exhibiting higher unconditioned responses relative to females. Our findings point to minimal to no sex differences in the expression of conditioned responses during acquisition and extinction of such responses. Functional MRI findings, however, show some distinct functional activations and connectivities between the sexes. These data suggest that males and females might use different neural mechanisms, mainly related to cognitive processing, to achieve comparable levels of acquired conditioned responses to threating cues.

Hippocampal Threat Reactivity Interacts with Physiological Arousal to Predict PTSD Symptoms

Hippo campal impairments are reliably associated with post-traumatic stress disorder (PTSD); however, little research has characterized how increased threat sensitivity may interact with arousal responses to alter hippocampal reactivity, and further how these interactions relate to the sequelae of trauma-related symptoms. In a sample of individuals recently exposed to trauma (N = 116, 76 female), we found that PTSD symptoms at 2 weeks were associated with decreased hippocampal responses to threat as assessed with fMRI. Further, the relationship between hippocampal threat sensitivity and PTSD symptomology only emerged in individuals who showed transient, high threat-related arousal, as assayed by an independently collected measure of fear potentiated startle. Collectively, our finding suggests that development of PTSD is associated with threat-related decreases in hippocampal function because of increases in fear-potentiated arousal.SIGNIFICANCE STATEMENT Alterations in hippocampal function linked to threat-related arousal are reliably associated with post-traumatic stress disorder (PTSD); however, how these alterations relate to the sequelae of trauma-related symptoms is unknown. Prior models based on nontrauma samples suggest that arousal may impact hippocampal neurophysiology leading to maladaptive behavior. Here we show that decreased hippocampal threat sensitivity interacts with fear-potentiated startle to predict PTSD symptoms. Specifically, individuals with high fear-potentiated startle and low, transient hippocampal threat sensitivity showed the greatest PTSD symptomology. These findings bridge literatures of threat-related arousal and hippocampal function to better understand PTSD risk.

Pleiotropic endophenotypic and phenotype effects of GABAergic neurosteroid synthesis deficiency in posttraumatic stress disorder

PTSD is associated with deficits in synthesis of progesterone metabolites such as allopregnanolone and pregnanolone that potently facilitate gamma-amino-butyric acid (GABA) effects at GABA_A receptors. These neurosteroids modulate neuronal firing rate, regional brain connectivity, and activation of amygdala-mediated autonomic nervous system, hypothalamic-pituitary-adrenal axis, and behavioral reactions to unconditioned and conditioned threat. They also play critical roles in learning and memory processes such as extinction and extinction retention and inhibit toll-like receptor activation of intracellular pro-inflammatory pathways. Deficient synthesis of these neurosteroids thus may contribute to individually variable PTSD clinical phenotypes encompassing symptom severity, capacity for PTSD recovery, and vulnerability to common PTSD-comorbidities such as major depression, chronic pain, alcohol and nicotine dependence, cardiovascular disease, metabolic syndrome, reproductive disorders, and autoimmune conditions.

PACAP-PAC1R modulates fear extinction via the ventromedial hypothalamus

Exposure to traumatic stress can lead to fear dysregulation, which has been associated with posttraumatic stress disorder (PTSD). Previous work showed that a polymorphism in the PACAP-PAC1R (pituitary adenylate cyclase-activating polypeptide) system is associated with PTSD risk in women, and PACAP (ADCYAP1)-PAC1R (ADCYAP1R1) are highly expressed in the hypothalamus. Here, we show that female mice subjected to acute stress immobilization (IMO) have fear extinction impairments related to Adcyap1 and Adcyap1r1 mRNA upregulation in the hypothalamus, PACAP-c-Fos downregulation in the Medial Amygdala (MeA), and PACAP-FosB/ΔFosB upregulation in the Ventromedial Hypothalamus dorsomedial part (VMHdm). DREADD-mediated inhibition of MeA neurons projecting to the VMHdm during IMO rescues both PACAP upregulation in VMHdm and the fear extinction impairment. We also found that women with the risk genotype of ADCYAP1R1 rs2267735 polymorphism have impaired fear extinction.

Enhancing exposure therapy for posttraumatic stress disorder (PTSD): a randomized clinical trial of virtual reality and imaginal exposure with a cognitive enhancer

Posttraumatic stress disorder (PTSD) is a significant public health issue. Yet, there are limited treatment options and no data to suggest which treatment will work for whom. We tested the efficacy of virtual reality exposure (VRE) or prolonged imaginal exposure (PE), augmented with D-cycloserine (DCS) for combat-related PTSD. As an exploratory aim, we examined whether brain-derived neurotrophic factor (BDNF) and fatty acid amide hydrolase (FAAH) moderated treatment response. Military personnel with PTSD (n = 192) were recruited into a multisite double-blind randomized controlled trial to receive nine weeks of VRE or PE, with DCS or placebo. Primary outcome was the improvement in symptom severity. Randomization was stratified by comorbid depression (MDD) and site. Participants in both VRE and PE showed similar meaningful clinical improvement with no difference between the treatment groups. A significant interaction (p = 0.45) suggested VRE was more effective for depressed participants (CAPS difference M = 3.51 [95% CI 1.17-5.86], p = 0.004, ES = 0.14) while PE was more effective for nondepressed participants (M = -8.87 [95% CI -11.33 to -6.40], p < 0.001, ES = -0.44). The main effect of DCS vs. placebo was not significant. Augmentation by MDD interaction (p = 0.073) suggested that depressed participants improved more on placebo (M = -8.43 [95% CI -10.98 to -5.88], p < 0.001, ES = -0.42); DCS and placebo were equally effective for nondepressed participants. There was an apparent moderating effect of BDNF Val66Met polymorphism on DCS augmentation (ES = 0.67). Met66 allele carriers improved more on DCS (ES = -0.25). FAAH 385 A carriers improved more than non-carriers (ES = 0.33), particularly those with MDD (ES = 0.62). This study provides a step toward precision therapeutics for PTSD by demonstrating that comorbid MDD and genetic markers may help guide treatment selection.ClinicalTrials.gov Identifier: NCT01352637.

Effects of 3,4-Methylenedioxymethamphetamine on Conditioned Fear Extinction and Retention in a Crossover Study in Healthy Subjects

Background: 3,4-Methylenedioxymethamphetamine (MDMA) has shown initial promise as an adjunct in psychotherapy to treat posttraumatic stress disorder (PTSD). Its efficacy and safety have been demonstrated across phase I-III studies. However, the mechanism underlying the potential utility of MDMA to treat PTSD in humans has not yet been thoroughly investigated. Preliminary evidence suggests that MDMA may facilitate fear extinction recall, which may be through the release of oxytocin. To test this hypothesis, we examined the efficacy of acute MDMA treatment to enhance fear extinction learning and recall. Methods: We used a two-period, double-blind, randomized, placebo-controlled crossover design in 30 healthy male subjects who received a placebo and a single dose of MDMA (125 mg). Fear extinction was tested using two separate Pavlovian fear conditioning paradigms, one using skin conductance response (SCR), and the other fear-potentiated startle (FPS) to conditioned cues. MDMA treatment occurred after fear conditioning and 2 h before extinction learning. Extinction recall was tested 23 h after MDMA intake. Additional outcome measures included subjective effects, emotion recognition tasks, plasma levels of oxytocin, and pharmacokinetics. Results: Fear conditioning and extinction learning were successful in both fear extinction paradigms (generalized eta-squared [ges] for SCR: 0.08; FPS: 0.07). Compared to placebo treatment, MDMA treatment significantly reduced SCRs to the reinforced conditioned stimulus (CS+) during extinction learning (ges = 0.03) and recall (ges = 0.06). Intensity of the subjective effects of MDMA (good effect, trust, and openness) during extinction learning negatively correlated with the discrimination between CS+ and the safety stimulus (CS-) during recall. MDMA did not influence FPS to conditioned cues. Oxytocin concentration was increased fourfold on average by MDMA during acute effects but was not associated with fear extinction outcomes. Conclusions: MDMA treatment facilitated rapid fear extinction and retention of extinction as measured by SCR to fear cues, in line with animal studies of MDMA facilitation of extinction. However, this effect may be limited to certain forms of learned fear responses, as it was not observed in the extinction model using startle reactivity as the outcome. This study provides further evidence for the facilitation of extinction with MDMA treatment and suggests this may be a component of its efficacy when paired with psychotherapy. Clinical Trial registration: clinicaltrials.gov identifier: NCT03527316.

Uncertain in the face of change: Lack of contingency shift awareness during extinction is associated with higher fear-potentiated startle and PTSD symptoms in children

Intolerance of uncertainty is a transdiagnostic risk factor for fear-related disorders and is associated with higher levels of anxiety in children and adolescents. It is unclear how uncertainty relates to development of psychopathology in children who have experienced trauma in early life. The present study used a fear-potentiated startle paradigm in children to examine associations between uncertainty (assessed as unawareness of a change in reinforcement during fear extinction) and symptoms of anxiety and posttraumatic stress disorder (PTSD), as well as startle potentiation to threat and safety cues. Results showed that unaware children had strong positive associations between trauma exposure and PTSD symptoms, whereas aware children did not. Uncertainty interacted with anxiety in that children who were both unaware and had higher anxiety displayed higher fear-potentiated startle to safety cues and did not show discrimination between threat and safety during fear conditioning. These results suggest that anxious children who persist in associating a threat cue with an aversive event during extinction, after repeated presentations of the no longer reinforced conditioned stimulus, may express psychophysiological phenotypes related to PTSD.

Sleep-Wake and Arousal Dysfunctions in Post-Traumatic Stress Disorder:Role of Orexin Systems

Post-traumatic stress disorder (PTSD) is a trauma-related condition that produces distressing fear memory intrusions, avoidance behaviors, hyperarousal/startle, stress responses and insomnia. This review focuses on the importance of the orexin neural system as a novel mechanism related to the pathophysiology of PTSD. Orexinergic neurons originate in the lateral hypothalamus and project widely to key neurotransmitter system neurons, autonomic neurons, the hypothalamic-pituitaryadrenal (HPA) axis, and fear-related neural circuits. After trauma or stress, the basolateral amygdala (BLA) transmits sensory information to the central nucleus of the amygdala (CeA) and in turn to the hypothalamus and other subcortical and brainstem regions to promote fear and threat. Orexin receptors have a prominent role in this circuit as fear conditioned orexin receptor knockout mice show decreased fear expression while dual orexin receptor antagonists (DORAs) inhibit fear acquisition and expression. Orexin activation of an infralimbic-amygdala circuit impedes fear extinction while DORA treatments enhance it. Increased orexin signaling to the amygdalocortical- hippocampal circuit promotes avoidance behaviors. Orexin has an important role in activating sympathetic nervous system (SNS) activity and the HPA axis stress responses. Blockade of orexin receptors reduces fear-conditioned startle responses. In PTSD models, individuals demonstrate sleep disturbances such as increased sleep latency and more transitions to wakefulness. Increased orexin activity impairs sleep by promoting wakefulness and reducing total sleep time while DORA treatments enhance sleep onset and maintenance. The orexinergic neural system provides important mechanisms for understanding multiple PTSD behaviors and provides new medication targets to treat this often persistent and debilitating illness.

Post-traumatic stress disorder: clinical and translational neuroscience from cells to circuits

Post-traumatic stress disorder (PTSD) is a maladaptive and debilitating psychiatric disorder, characterized by re-experiencing, avoidance, negative emotions and thoughts, and hyperarousal in the months and years following exposure to severe trauma. PTSD has a prevalence of approximately 6-8% in the general population, although this can increase to 25% among groups who have experienced severe psychological trauma, such as combat veterans, refugees and victims of assault. The risk of developing PTSD in the aftermath of severe trauma is determined by multiple factors, including genetics - at least 30-40% of the risk of PTSD is heritable - and past history, for example, prior adult and childhood trauma. Many of the primary symptoms of PTSD, including hyperarousal and sleep dysregulation, are increasingly understood through translational neuroscience. In addition, a large amount of evidence suggests that PTSD can be viewed, at least in part, as a disorder that involves dysregulation of normal fear processes. The neural circuitry underlying fear and threat-related behaviour and learning in mammals, including the amygdala-hippocampus-medial prefrontal cortex circuit, is among the most well-understood in behavioural neuroscience. Furthermore, the study of threat-responding and its underlying circuitry has led to rapid progress in understanding learning and memory processes. By combining molecular-genetic approaches with a translational, mechanistic knowledge of fear circuitry, transformational advances in the conceptual framework, diagnosis and treatment of PTSD are possible. In this Review, we describe the clinical features and current treatments for PTSD, examine the neurobiology of symptom domains, highlight genomic advances and discuss translational approaches to understanding mechanisms and identifying new treatments and interventions for this devastating syndrome.

Startle Latency as a Potential Marker for Amygdala-Mediated Hyperarousal

BACKGROUND

Fear-related disorders are characterized by hyperexcitability in reflexive circuits and maladaptive associative learning mechanisms. The startle reflex is suited to investigate both processes, either by probing it under baseline conditions or by deriving it in fear conditioning studies. In anxiety research, the amplitude of the fear-potentiated startle has been shown to be influenced by amygdalar circuits and has typically been the readout of interest. In schizophrenia research, prolonged startle peak latency under neutral conditions is an established readout, thought to reflect impaired processing speed. We therefore explored whether startle latency is an informative readout for human anxiety research.

METHODS

We investigated potential similarities and differences of startle peak latency and amplitude derived from a classical fear conditioning task in a sample of 206 participants with varying severity levels of anxiety disorders and healthy control subjects. We first reduced startle response to stable components and regressed individual amygdala gray matter volumes onto the resulting startle measures. We then probed time, stimulus, and group effects of startle latency.

RESULTS

We showed that startle latency and startle amplitude were 2 largely uncorrelated measures; startle latency, but not amplitude, showed a sex-specific association with gray matter volume of the amygdala; startle latencies showed a fear-dependent task modulation; and patients with fear-related disorders displayed shorter startle latencies throughout the fear learning task.

CONCLUSIONS

These data provide support for the notion that probing startle latencies under threat may engage amygdala-modulated threat processing, making them a complementary marker for human anxiety research.

Acquisition, extinction, and return of fear in veterans in intensive outpatient prolonged exposure therapy: A fear-potentiated startle study

Prolonged exposure (PE) therapy is a first-line treatment for posttraumatic stress disorder (PTSD) and involves repeated presentation of trauma-related cues without aversive outcomes. A primary learning mechanism of PE is fear extinction (new learning that a dangerous cue is now safe) and its retention (maintaining this new learning over time). Extant research suggests extinction is impaired in PTSD patients. In this study, we employed an established fear-potentiated startle-based paradigm to examine fear acquisition, extinction learning and retention before and after completion of intensive outpatient treatment. First, PTSD patients undergoing PE (n = 55) were compared to trauma-exposed patients without PTSD (n = 57). We identified excessive fear in PTSD patients during acquisition and extinction before treatment compared to non-PTSD patients. At post-treatment, we examined the return of fear after extinction in PTSD patients showing high or low treatment response to PE (≥50% change in PTSD symptom severity vs. < 50%). High PE responders maintained fear extinction learning whereas low PE responders showed significant return of fear at post-treatment. These results replicate and extend previous findings of impaired extinction in PTSD and provide support for the proposed theoretical link between fear extinction and PE response.