Biology subjects

Morriss, J.

Publications and source records attributed to Morriss, J..

9 recordsLinked to original sources

bioRxiv2024

The influence of trait intolerance of uncertainty on behavioural flexibility

Identifying and responding adaptively to a change in our environment is an essential skill. However, differences in our ability to detect and our disposition to react to these changes mean that some individuals are better equipped to deal with change than others. Here, we investigate whether intolerance of uncertainty, a transdiagnostic dimension of psychopathology, is associated with performance during a reversal learning task. We assessed task performance of 145 subjects using behavioural measures and computational modelling across two time points (approximately 12 days apart). Intolerance of uncertainty and its prospective and inhibitory subscales were associated with task performance, irrespective of self-reported levels of trait anxiety. Intolerance of uncertainty and its inhibitory subscale were positively associated with increased sensitivity to reinforcement from positive, but not negative, feedback. Furthermore, the inhibitory subscale was positively associated with better performance, both overall (as indexed by accuracy) and immediately following a change in reward contingencies (as indexed by perseveration). Lastly, the prospective subscale interacted with the extent to which choice was driven by expected value across time points. These findings provide novel evidence for how trait intolerance of uncertainty may modulate behavioural flexibility in changeable environments. The study points towards exciting avenues for further research into the development of IU-related behaviours across the lifespan and their implications for mental health.

animal behavior and cognition↗

bioRxiv2020

Intolerance of uncertainty is associated with heightened responding in the prefrontal cortex during instructed threat of shock

Heightened responding to uncertain threat is considered a hallmark of anxiety disorder pathology. Here, we sought to determine if individual differences in self-reported intolerance of uncertainty (IU), a key transdiagnostic dimension in anxiety-related pathology, underlies differential recruitment of neural circuitry during instructed outcome uncertainty of threat (n = 42). In an instructed threat of shock task, cues signalled uncertain threat of shock (50%) or certain safety from shock outcomes. Ratings of arousal and valence, skin conductance response (SCR) and functional magnetic resonance imaging were acquired. Overall, participants displayed greater ratings of arousal and negative valence, SCR, and amygdala activation to uncertain threat vs. safe cues. IU was not associated with greater arousal ratings, SCR or amygdala activation to uncertain threat vs. safe cues. However, we found that high IU was associated with greater ratings of negative valence and greater activity in the medial prefrontal cortex and dorsomedial rostral prefrontal cortex to uncertain threat vs safe cues. These findings suggest that during instructed outcome uncertainty of threat, individuals high in IU rate uncertain threat as aversive and engage prefrontal cortical regions known to be involved in safety-signalling and conscious threat appraisal. Taken together, these findings highlight the potential of IU in modulating safety-signalling and conscious appraisal mechanisms in situations with instructed outcome uncertainty of threat, which may be relevant to models of anxiety-related pathology.

neuroscience↗

bioRxiv2020

The role of intolerance of uncertainty in the acquisition and extinction of reward

Individuals, who score high in self-reported intolerance of uncertainty (IU), tend to find uncertainty anxiety-provoking. IU has been reliably associated with disrupted threat extinction. However, it remains unclear whether IU would be related to disrupted extinction to other arousing stimuli that are not threatening (i.e., rewarding). We addressed this question by conducting a reward associative learning task with acquisition and extinction training phases (n = 58). Throughout the associative learning task, we recorded valence ratings (i.e. liking), skin conductance response (SCR) (i.e. sweating), and corrugator supercilii activity (i.e. brow muscle indicative or negative and positive affect) to learned reward and neutral cues. During acquisition training with partial reward reinforcement, higher IU was associated with greater corrugator supercilii activity to neutral compared to reward cues. IU was not related to valence ratings or SCRs during the acquisition or extinction training phases. These preliminary results suggest that IU-related deficits during extinction may be limited to situations with threat. The findings further our conceptual understanding of IUs role in the associative learning and extinction of reward, and in relation to the processing of threat and reward more generally.

neuroscience↗

bioRxiv2019

Longitudinal change in executive function is associated with impaired top-down frontolimbic regulation during reappraisal in older adults

Networks in the prefrontal cortex (PFC) that are important for executive function are also engaged in adaptive responding to negative events. These networks are particularly vulnerable to age-related structural atrophy and an associated loss of executive function, yet existing evidence suggests preserved emotion processing ability in aging. Using longitudinally acquired data from a battery of cognitive tasks, we defined a metric for the rate of decline of executive function. With this metric, we investigated relationships between changes in executive function and emotion reappraisal ability and brain structure, in older adults using functional and structural MRI. During task-based fMRI, participants were asked to cognitively reappraise negatively valenced images. We hypothesised one of two associations with decreasing executive function over time: 1) a decreased ability to reappraise reflected in decreased PFC and increased amygdala activation, or 2) a neural compensation mechanism characterised by increased PFC activation but no differential amygdala activation. Structurally, for a decreased reappraisal ability, we predicted a decrease in grey matter in PFC and/or a decrease of white matter integrity in amygdala-PFC pathways. Neither of the two hypotheses relating to brain function were completely supported, with the findings indicating a steeper decline in executive function associated with both increased PFC and increased left amygdala activity when reappraising negative stimuli. In addition, white matter integrity of the uncinate fasciculus, a primary white matter tract connecting the amygdala and ventromedial areas of PFC, was lower in those individuals who demonstrated a greater decrease in executive function. These findings highlight that when cognitive ability diminishes, active top-down emotional control is compromised.

neuroscience↗

bioRxiv2019

What do I do now? Intolerance of uncertainty is associated with discrete patterns of anticipatory physiological responding to different uncertain contexts

Heightened physiological responses to uncertainty are a common hallmark of anxiety disorders. Many separate studies have examined the relationship between individual differences in intolerance of uncertainty (IU) and physiological responses to uncertainty during different contexts. Despite this, little is known about the extent to which physiological responses during different uncertain contexts covary within individuals based on IU. Anticipatory physiological responses to uncertainty were assessed in three different contexts (associative threat learning, basic threat uncertainty, decision-making) within the same sample (n = 45). During these tasks, behavioural responses (i.e. reaction times, choices), skin conductance and corrugator supercilli activity were recorded. In addition, self-reported IU and trait anxiety were measured. IU made different contributions to the physiological measures during each task. IU was found to modulate both skin conductance and corrugator supercilii activity for the associative threat learning and decision-making contexts. However, trait anxiety was found to modulate corrugator supercilii activity during the basic threat uncertainty context. Ultimately, this research helps us further tease apart the role of IU in different uncertain contexts, which will be relevant for future IU-related models of psychopathology.

neuroscience↗

bioRxiv2018

The devil is in the detail: The role of threat level and intolerance of uncertainty in extinction

Recent evidence suggests that individual differences in intolerance of uncertainty (IU) are associated with disrupted threat extinction. However, it is unknown what maintains the learned threat association in high IU individuals: is it the experienced uncertainty during extinction or the combination of experienced uncertainty with potential threat during extinction? Here we addressed this question by running two independent experiments with uncertain auditory stimuli that varied in threat level (Experiment 1, aversive human scream (n = 30); Experiment 2, benign tone (n = 47) and mildly aversive tone (n = 49)). During the experiments, we recorded skin conductance responses and subjective ratings to the learned cues during acquisition and extinction. In experiment 1, high IU was associated with heightened skin conductance responding to the learned threat vs. safe cue during extinction. In experiment 2, high IU was associated only with larger skin conductance responding to the learned cues with threatening properties during extinction i.e. mildly aversive tone. These findings suggest that uncertainty in combination with threat, even when mild, disrupts extinction in high IU individuals. Such findings help us understand the link between IU and threat extinction, and its relevance to anxiety disorder pathology.

neuroscience↗

bioRxiv2018

Knowledge is power: Contingency instruction promotes threat extinction in high intolerance of uncertainty individuals

Extinction-resistant threat is considered to be a central feature of pathological anxiety. Reduced threat extinction is observed in individuals with high intolerance of uncertainty (IU). Here we sought to determine whether contingency instructions could alter the course threat extinction for individuals high in IU. We tested this hypothesis in two identical experiments (Exp 1 n = 60, Exp 2 n = 82) where we recorded electrodermal activity during threat acquisition with partial reinforcement, and extinction. Participants were split into groups based on extinction instructions (instructed, uninstructed) and IU score (low, high). All groups displayed larger skin conductance responses to learned threat versus safety cues during threat acquisition, indicative of threat conditioning. In both experiments, only the uninstructed high IU groups displayed larger skin conductance responses to the learned threat versus safety cue during threat extinction. These findings suggest that uncertain threat during extinction maintains conditioned responding in individuals high in IU.

neuroscience↗

bioRxiv2018

Out with the old and in with the new: The role of intolerance of uncertainty in reversal of threat and safety

The ability to learn and reverse threat associations is crucial for survival. The extent to which old threat associations are inhibited and new threat associations are formed may depend on sensitivity to future threat uncertainty. To assess the extent to which Intolerance of Uncertainty (IU) predicts threat learning and reversal, we recorded expectancy ratings and skin conductance in 44 healthy participants during an associative learning paradigm, where threat and safety contingencies were reversed. During acquisition and reversal, we observed larger SCR magnitude and expectancy ratings for threat vs. safety cues. However, during reversal higher IU was associated with larger SCR magnitude to new threat vs. new safety cues, compared to lower IU. These results were specific to IU-related variance, over shared variance with trait anxiety (STAIX-2). Overall, these findings suggest that individuals high in IU are able to reverse threat and safety associations in the presence of direct threat. Such findings help us understand the recently revealed link between IU and threat extinction, where direct threat is absent. Moreover, these findings highlight the potential relevance of IU in clinical intervention and treatment for anxiety disorders.

neuroscience↗

bioRxiv2018

Multimodal evidence for delayed fear extinction in adolescence and young adulthood.

Previous research in rodents and humans points to an evolutionarily conserved profile of blunted fear extinction during adolescence, underpinned by brain structures such as the amygdala and medial prefrontal cortex (mPFC). In this study, we examine age-related effects on the function and structural connectivity of this system in fear extinction in adolescence and young adulthood. Younger age was associated with greater amygdala activity and delayed mPFC engagement to learned threat cues as compared to safety cues. Furthermore, greater structural integrity of the uncinate fasciculus, a white matter tract that connects the amygdala and mPFC, mediated the relationship between age and acceleration of mPFC engagement during extinction. These findings suggest that age-related changes in the structure and function of amygdala-mPFC circuitry may underlie the protracted maturation of fear regulatory processes, rendering younger individuals more vulnerable to anxiety disorders, which emerge during development.

neuroscience↗