ORCID Profile
0000-0002-6376-8354
Current Organisation
University of Tasmania
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Publisher: SAGE Publications
Date: 07-2022
DOI: 10.1177/20438087221112330
Abstract: Intolerance of uncertainty (IU) is a transdiagnostic risk factor for psychiatric disorders, and plays an important role in fear and threat learning under uncertainty. The ‘reinstatement of fear/threat’ is an understudied phenomenon thought to represent clinical symptom relapse. Reinstatement of conditioned responding can be captured in the laboratory by presenting unsignaled presentations of an aversive unconditional stimulus. The present study investigated IU as a predictor of reinstatement effects, such that in iduals higher in IU, relative to lower IU, would show larger reinstatement. Sixty-two participants completed the Intolerance of Uncertainty Scale and provided threat expectancy ratings (i.e. certainty of receiving a shock) during a differential threat conditioning and extinction paradigm with reinstatement. Findings suggested a differential increase in threat expectancy ratings to both the threat and safety cue following reinstatement, although this effect was small and did not survive follow-up tests. Nevertheless, IU was a significant predictor of reinstatement to the threat cue but not the safety cue, although this effect was not in the expected direction. Specifically, higher IU was associated with reduced threat expectancy ratings post-reinstatement. These findings provide support for the limited literature demonstrating an important role for IU in reinstatement effects and should be investigated further.
Publisher: Elsevier BV
Date: 08-2017
DOI: 10.1016/J.JAD.2017.04.016
Abstract: Considerable research has revealed impaired fear extinction to be a significant predictor of PTSD. Fear extinction is also considered the primary mechanism of exposure therapy, and a critical factor in PTSD recovery. The cognitive theory of PTSD proposes that symptoms persist due to excessive negative appraisals about the trauma and its sequelae. Research has not yet examined the relationship between fear extinction and negative appraisals in PTSD. A cross-sectional s le of participants with PTSD (n =21), and trauma-exposed controls (n =33) underwent a standardized differential fear conditioning and extinction paradigm, with skin conductance response (SCR) litude serving as the index of conditioned responses. The Posttraumatic Cognitions Inventory (PTCI) was used to index catastrophic negative appraisals. Participants with PTSD demonstrated a slower decrease in overall SCR responses during extinction and greater negative appraisals compared to the group. A moderation analysis revealed that both negative trauma-relevant appraisals and fear extinction learning were independently associated with PTSD symptoms, but there was no moderation interaction. The current study was limited by a modest s le size, leading to the inclusion of participants with subclinical PTSD symptoms. Further, the current study only assessed fear extinction learning including a second day extinction recall task may show alternative effects. These findings indicate that negative appraisals and fear extinction did not interact, but had independent relationships with PTSD symptoms. Here we show for the first time in an experimental framework that negative appraisals and fear extinction play separate roles in PTSD symptoms.
Publisher: Elsevier BV
Date: 05-2018
DOI: 10.1016/J.PSYNEUEN.2018.03.002
Abstract: The low expression Met allele of the BDNF Val66Met polymorphism is associated with impaired fear extinction in healthy controls, and poorer response to exposure therapy in patients with Posttraumatic Stress Disorder (PTSD). Given that fear extinction underlies exposure therapy, this raises the question of the impact of BDNFVal66Met polymorphism on fear extinction in PTSD, yet this question has not yet been examined. One hundred and six participants (22 PTSD, 46 trauma-exposed controls (TC) and 38 non-trauma exposed controls (NTC)) completed a fear conditioning and extinction task and saliva s les were taken for DNA extraction and genotyped for the BDNF Val66Met polymorphism. Moderation analyses using PROCESS examined whether BDNF genotype (Val-Val vs Met carriers) moderated the relationship between PTSD symptom severity (and diagnostic status) and skin conductance response (SCR) litude during fear extinction. The PTSD group displayed significantly slower fear extinction learning compared to TC and NTC in the early extinction phase. The BDNF Val66Met polymorphism moderated the relationship between PTSD and fear extinction learning, such that poorer fear extinction learning was associated with greater PTSD symptom severity (and PTSD diagnostic status) in in iduals with the low-expression Met allele, but no relationship was demonstrated in in iduals with the Val-Val allele. This study reveals that impaired fear extinction learning is particularly evident in in iduals with PTSD who carry the low-expression BDNF Met allele and importantly not in those with the Val-Val allele. This provides novel evidence of a link between BDNF and impaired fear extinction learning in PTSD, which may contribute to poorer response to exposure therapy.
Publisher: Elsevier BV
Date: 11-2017
DOI: 10.1016/J.BANDC.2017.07.001
Abstract: Posttraumatic Stress Disorder (PTSD) and mild traumatic brain injury (mTBI) are common comorbidities during military deployment that affect emotional brain processing, yet few studies have examined the independent effects of mTBI and PTSD. The purpose of this study was to examine distinct differences in neural responses to emotional faces in mTBI and PTSD. Twenty-one soldiers reporting high PTSD symptoms were compared to 21 soldiers with low symptoms, and 16 soldiers who reported mTBI-consistent injury and symptoms were compared with 16 soldiers who did not sustain an mTBI. Participants viewed emotional face expressions while their neural activity was recorded (via event-related potentials) prior to and following deployment. The high-PTSD group displayed increased P1 and P2 litudes to threatening faces at post-deployment compared to the low-PTSD group. In contrast, the mTBI group displayed reduced face-specific processing (N170 litude) to all facial expressions compared to the no-mTBI group. Here, we identified distinctive neural patterns of emotional face processing, with attentional biases towards threatening faces in PTSD, and reduced emotional face processing in mTBI.
Publisher: Elsevier BV
Date: 04-2018
DOI: 10.1016/J.PSYCHRES.2018.02.016
Abstract: Posttraumatic Stress Disorder (PTSD) is associated with elevated noradrenergic signaling, which has an impact on emotional learning and memory. Fear extinction is thought to underlie the processes of exposure therapy, however the relationship between noradrenaline and extinction in PTSD is unclear. Participants with PTSD (n = 21), trauma-exposure without PTSD (TC n = 36), and non-trauma-exposed controls (NTC n = 27) completed a fear conditioning and extinction paradigm, and conditioned fear was indexed by skin conductance response (SCR). Salivary α-amylase (sAA) collected at baseline and immediately post-fear acquisition was used as an index of noradrenaline, and we examined whether sAA in response to fear acquisition was a moderator between fear extinction and PTSD symptoms. While there was a significant increase in sAA from baseline to post-fear acquisition, this was not modulated by group. Compared to TC and NTC, the PTSD group displayed a slower decline in SCRs during early extinction, which generalized across stimulus type, and was not moderated by sAA. These findings suggest that the relationship between fear extinction and PTSD symptoms does not change as a function of sAA levels however previous research suggests other processes of fear learning may be associated with noradrenergic activity in PTSD.
Publisher: Elsevier BV
Date: 07-2021
Publisher: Elsevier BV
Date: 10-2021
Publisher: Elsevier BV
Date: 04-2017
DOI: 10.1016/J.PSYNEUEN.2017.01.012
Abstract: Posttraumatic stress symptoms (PTSS) are commonly associated with impairments in extinguishing fear to signals previously associated with danger, and also with inhibiting fear to safety signals. Previous studies indicate that PTSS are associated with low cortisol activity, and cortisol is shown to facilitate fear extinction. Few studies have examined the influence of cortisol reactivity on fear extinction in PTSS. We used a standardized fear conditioning and extinction paradigm to investigate the relationship between fear extinction and endogenous salivary cortisol activity in participants with high PTSS (n=18), trauma-exposed controls (n=33), and non-trauma-exposed controls (n=27). Skin conductance response (SCR) was used as an index of conditioned responding. Saliva s les were collected at baseline, and 20min post-fear acquisition for basal and reactive cortisol levels, respectively. PTSS participants demonstrated a slower rate of extinction learning during the early extinction phase. A moderation analysis revealed that cortisol reactivity was a significant moderator between fear inhibition to the safety signal (CS-) during early extinction and PTSS, but not to the threat signal (CS+). Specifically, this interaction was significant in two ways: (1) participants with elevated cortisol reactivity showed lower PTSS as fear inhibition improved and (2) participants with low cortisol reactivity showed higher PTSS as fear inhibition improved. The findings of the present study show that the relationship between fear inhibition and cortisol reactivity is complex, and suggest that cortisol reactivity shapes safety signal learning in PTSS.
Publisher: Informa UK Limited
Date: 18-12-2014
Publisher: Elsevier BV
Date: 12-2018
DOI: 10.1016/J.IJPSYCHO.2018.10.010
Abstract: Fear conditioning and extinction is a construct integral to understanding trauma-, stress- and anxiety-related disorders. In the laboratory, associative learning paradigms that pair aversive with neutral stimuli are used as analogues to real-life fear learning. These studies use physiological indices, such as skin conductance, to sensitively measure rates and intensity of learning and extinction. In this review, we discuss some of the potential limitations in interpreting and analysing physiological data during the acquisition or extinction of conditioned fear. We argue that the utmost attention should be paid to the development of modelling approaches of physiological data in associative learning paradigms, by illustrating the lack of replicability and interpretability of results in current methods. We also show that statistical significance may be easily achieved in this paradigm without more stringent data and data analysis reporting requirements, leaving this particular field vulnerable to misleading conclusions. This review is written so that issues and potential solutions are accessible to researchers without mathematical training. We conclude the review with some suggestions that all laboratories should be able to implement, including visualising the full data set in publications and adopting modelling, or at least regression-based, approaches.
Publisher: Public Library of Science (PLoS)
Date: 24-05-2022
DOI: 10.1371/JOURNAL.PONE.0268814
Abstract: Fear conditioning paradigms are critical to understanding anxiety-related disorders, but studies use an inconsistent array of methods to quantify the same underlying learning process. We previously demonstrated that selection of trials from different stages of experimental phases and inconsistent use of average compared to trial-by-trial analysis can deliver significantly ergent outcomes, regardless of whether the data is analysed with extinction as a single effect, as a learning process over the course of the experiment, or in relation to acquisition learning. Since small s le sizes are attributed as sources of poor replicability in psychological science, in this study we aimed to investigate if changes in s le size influences the ergences that occur when different kinds of fear conditioning analyses are used. We analysed a large data set of fear acquisition and extinction learning (N = 379), measured via skin conductance responses (SCRs), which was res led with replacement to create a wide range of bootstrapped databases ( N = 30, N = 60, N = 120, N = 180, N = 240, N = 360, N = 480, N = 600, N = 720, N = 840, N = 960, N = 1080, N = 1200, N = 1500, N = 1750, N = 2000) and tested whether use of different analyses continued to produce deviating outcomes. We found that s le size did not significantly influence the effects of inconsistent analytic strategy when no group-level effect was included but found strategy-dependent effects when group-level effects were simulated. These findings suggest that confounds incurred by inconsistent analyses remain stable in the face of s le size variation, but only under specific circumstances with overall robustness strongly hinging on the relationship between experimental design and choice of analyses. This supports the view that such variations reflect a more fundamental confound in psychological science—the measurement of a single process by multiple methods.
Publisher: Hindawi Limited
Date: 06-01-2016
DOI: 10.1002/DA.22463
Abstract: Prior research has demonstrated that time-of-day may play an important role in the extinction of conditioned fear, with extinction better learned earlier in the day rather than later. Impaired fear extinction memory is widely considered a key mechanism of posttraumatic stress disorder (PTSD). The relationship between fear extinction and PTSD symptoms may be moderated by hours-since-waking. In the present experiment, we examined whether hours-since-waking would moderate fear extinction learning ability in a clinical PTSD s le (n = 15), compared to trauma-exposed (n = 33) and nonexposed controls (n = 22). Participants completed a standardized differential fear conditioning and extinction paradigm, providing skin conductance response measures to quantify conditioned responding. Mixed-model analysis of variance revealed a PTSD-specific impairment in extinction learning ability in the late extinction phase. A moderation analysis showed that hours-since-waking was a significant moderator of the relationship between impaired late extinction and PTSD symptoms. Specifically, we found that participants with higher PTSD symptoms demonstrated poorer fear extinction learning ability as they were awake for longer. The results of the current study add to a growing literature indicating deficits in fear extinction learning in PTSD s les, compared to trauma-exposed and nonexposed controls. These results support previous findings that fear extinction is impaired later in the day, and extends this to a clinical s le, suggesting that exposure-therapy may be optimized by scheduling sessions in the morning.
Publisher: Public Library of Science (PLoS)
Date: 06-12-2018
Publisher: Elsevier BV
Date: 11-2018
DOI: 10.1016/J.BRAT.2018.08.005
Abstract: Fear reinstatement is one of several paradigms designed to measure fear return following extinction, as a laboratory model for the relapse of Posttraumatic Stress Disorder (PTSD) symptoms. Sleep is a key factor in emotional memory consolidation, and here we examined the relationship between sleep quality and fear reinstatement in PTSD, relative to trauma-exposed and non-exposed controls. The Pittsburgh Sleep Quality Index (PSQI) was used as a subjective measure of sleep quality, and skin conductance responses (SCR) and unconditioned stimulus (US)-expectancy ratings were used to index threat responses during a differential fear conditioning, extinction, and reinstatement paradigm. There were no significant between-group differences in the reinstatement of conditioned responding. Sleep disturbance and sleep onset latency were significant moderators between reinstatement of fear and PTSD symptom severity, such that there was a positive relationship between PTSD symptoms and fear reinstatement for higher levels - but not lower levels - of sleep disturbance and sleep onset latency. To our knowledge, this is the first study to investigate PTSD-specific reinstatement patterns and sleep as a boundary condition of reinstatement. Future research using polysomnographic measures of sleep-wave architecture may further clarify the relationship between fear reinstatement and sleep quality in clinical s les with PTSD relative to controls.
Publisher: Elsevier BV
Date: 10-2016
DOI: 10.1016/J.NEUBIOREV.2016.07.014
Abstract: Recent prospective studies in emergency services have identified impaired fear extinction learning and memory to be a significant predictor of Posttraumatic Stress Disorder (PTSD), complementing a wealth of cross-sectional evidence of extinction deficits associated with the disorder. Additional fields of research show specific risk factors and biomarkers of the disorder, including candidate genotypes, stress and sex hormones, cognitive factors, and sleep disturbances. Studies in mostly nonclinical populations also reveal that the aforementioned factors are involved in fear extinction learning and memory. Here, we provide a comprehensive narrative review of the literature linking PTSD to these risk factors, and linking these risk factors to impaired fear extinction. On balance, the evidence suggests that fear extinction may play a role in the relationship between risk factors and PTSD. Should this notion hold true, this review carries important implications for the improvement of exposure-based treatments, as well as strategies for the implementation of treatment.
Publisher: SAGE Publications
Date: 09-2014
Abstract: Trying to remember something now typically improves your ability to remember it later. However, after watching a video of a simulated bank robbery, participants who verbally described the robber were 25% worse at identifying the robber in a lineup than were participants who instead listed U.S. states and capitals—this has been termed the “verbal overshadowing” effect (Schooler & Engstler-Schooler, 1990). More recent studies suggested that this effect might be substantially smaller than first reported. Given uncertainty about the effect size, the influence of this finding in the memory literature, and its practical importance for police procedures, we conducted two collections of preregistered direct replications (RRR1 and RRR2) that differed only in the order of the description task and a filler task. In RRR1, when the description task immediately followed the robbery, participants who provided a description were 4% less likely to select the robber than were those in the control condition. In RRR2, when the description was delayed by 20 min, they were 16% less likely to select the robber. These findings reveal a robust verbal overshadowing effect that is strongly influenced by the relative timing of the tasks. The discussion considers further implications of these replications for our understanding of verbal overshadowing.
Publisher: Elsevier BV
Date: 2019
DOI: 10.1016/J.PNPBP.2018.08.014
Abstract: The classical conditioning paradigm of fear learning has spawned a number of experimental variations for the explanation of posttraumatic stress disorder (PTSD) etiology. These paradigms include extinction learning and recall, fear inhibition, fear generalization, and conditioned avoidance. As such, each of these paradigms have significant applications for understanding the development, maintenance, treatment, and relapse of the fear-related features of PTSD. In the present review, we describe each of these conditioning-based paradigms with reference to the clinical applications, and supported by case ex les from patients with severe PTSD symptoms. We also review the neurobiological models of conditioning and extinction in animals, psychiatrically healthy humans, and PTSD patients, and discuss the current balance of evidence suggesting a number of biological, behavioral, and cognitive mechanisms/moderators of the conditioning and extinction process in experimental and clinical contexts.
Location: United Kingdom of Great Britain and Northern Ireland
No related grants have been discovered for Daniel Zuj.