A predictive coding account of value-based learning in PTSD: Implications for precision treatments

Associations among threat prediction error, prediction change, and anxiety during an exposure therapy analogue in adults with healthy to clinical social anxiety

Contemporary exposure therapy models for anxiety argue that exposures must generate threat prediction error to be effective. More research is needed to test this claim in clinical settings. This study explored how threat prediction error learning relates to outcomes during an exposure analogue procedure. Adult undergraduate psychology students (N = 125) experiencing a broad range of social anxiety symptoms from healthy to clinical levels of social anxiety completed 667 online speech performance exposures over two testing sessions separated by a week (approx. 3 speeches/session). Self-reported anxiety, threat prediction, threat outcome, and surprise were measured for each exposure and used to derive learning indicators. These included threat prediction error, prediction change, and the extent that prediction errors were converted to prediction change (i.e., learning rate). We examined between- and within-person relationships between these learning indicators and outcomes over exposure using multilevel modelling. Average prediction change and prediction error learning rate, but not average prediction error per se, was associated with more anxiety reduction across the exposure. Within-person, anxiety was lower after exposures that triggered more prediction change. Threat prediction error was not linearly associated with anxiety at the next exposure. Higher threat prediction error during an exposure was associated with greater subjective surprise for that exposure. We concluded that exposure outcomes depend on how much the patient converts exposure-related prediction errors into threat prediction change. Future research should focus on strategies to enhance the prediction-error learning rate from exposures.

Plasticity of human resilience mechanisms

The hippocampus's vulnerability to trauma-induced stress can lead to pathophysiological disturbances that precipitate the development of posttraumatic stress disorder (PTSD). The mechanisms of resilience that foster remission and mitigate the adverse effects of stress remain unknown. We analyzed the evolution of hippocampal morphology between 2016/2017 and 2018/2019, as well as the memory control mechanisms crucial for trauma resilience. Participants were individuals exposed to the 2015 Paris terrorist attacks (N = 100), including chronic (N = 34) and remitted (N = 19) PTSD, and nonexposed (N = 72). We found that normalization of inhibitory control processes, which regulate the resurgence of intrusive memories in the hippocampus, not only predicted PTSD remission but also preceded a reduction in traumatic memories. Improvement in control mechanisms was associated with the interruption of stress-induced atrophy in a hippocampal region that includes the dentate gyrus. Human resilience to trauma is characterized by the plasticity of memory control circuits, which interacts with hippocampal neuroplasticity.

Auditory illusions and Post-traumatic stress disorder: Sound test in a case-control study

Post-Traumatic Stress Disorder (PTSD) is a prevalent and disabling disorder with a high degree of comorbidity. Clinical studies have focused on hallucinations, which could be associated with the severity of the disorder and treatment resistance. Auditory illusions have received little attention so far, possibly because they are particularly difficult to assess. However, they may impact functioning, and underdiagnosis could impair prognosis. To provide a clearer understanding of PTSD psychopathology, this paper proposes to focus on these auditory illusions. A monocentric case-control study was conducted on 30 subjects with PTSD and 30 controls, based on an original design. False recognitions were estimated during a sound test created with a vocoder. Additionally, differences in emotional valence, dissociation, hyperarousal, and reliving were assessed. The study found that individuals with PTSD experience a higher frequency of auditory illusions compared to healthy controls (65% versus 20%, p < 0.001). Additionally, the emotional valence of these illusions was more negative in individuals with PTSD than in controls. The study also identified a correlation between dissociation symptoms, hyperarousal and reliving with auditory illusions. These findings are in line with neurobiological studies of PTSD, as well as cognitive predictive models, and support the hypothesis of a significant prevalence of auditory illusions in PTSD. Like hallucinations, auditory illusions may be influenced by dissociation. Although these results are preliminary, they suggest a need for further investigation into auditory illusions in PTSD and their effect on prognosis.

Neuroimaging evidence of disturbed self-appraisal in posttraumatic stress disorder: A systematic review

BACKGROUND

The experience of self-hood in posttraumatic stress disorder (PTSD) is altered cognitively and somatically. Dysfunctional negative cognitions about the self are a central mechanism of PTSD symptomatology and treatment. However, while higher-order brain models of disturbances in self-appraisal (i.e., cognitive processes relating to evaluating the self) have been examined in other psychiatric disorders, it is unclear how normative brain function during self-appraisal is impaired in PTSD.

METHODS

This paper presents a PRISMA systematic review of functional neuroimaging studies (n = 5), to establish a neurobiological account of how self-appraisal processes are disturbed in PTSD. The review was prospectively registered with PROSPERO (CRD42023450509).

RESULTS

Self-appraisal in PTSD is linked to disrupted activity in core self-processing regions of the Default Mode Network (DMN); and regions involved in cognitive control and emotion regulation, salience and valuation.

LIMITATIONS

Because self-appraisal in PTSD is relatively under-studied, only a small number of studies could be included for review. Cross-study heterogeneity in analytic approaches and trauma-exposure history prohibited a quantitative meta-analysis.

CONCLUSIONS

This paper proposes a mechanistic account of how neural dysfunctions may manifest clinically in PTSD and inform targeted selection of appropriate treatment options. We present a research agenda for future work to advance the field.

Temporal stability of Bayesian belief updating in perceptual decision-making

Bayesian inference suggests that perception is inferred from a weighted integration of prior contextual beliefs with current sensory evidence (likelihood) about the world around us. The perceived precision or uncertainty associated with prior and likelihood information is used to guide perceptual decision-making, such that more weight is placed on the source of information with greater precision. This provides a framework for understanding a spectrum of clinical transdiagnostic symptoms associated with aberrant perception, as well as individual differences in the general population. While behavioral paradigms are commonly used to characterize individual differences in perception as a stable characteristic, measurement reliability in these behavioral tasks is rarely assessed. To remedy this gap, we empirically evaluate the reliability of a perceptual decision-making task that quantifies individual differences in Bayesian belief updating in terms of the relative precision weighting afforded to prior and likelihood information (i.e., sensory weight). We analyzed data from participants (n = 37) who performed this task twice. We found that the precision afforded to prior and likelihood information showed high internal consistency and good test-retest reliability (ICC = 0.73, 95% CI [0.53, 0.85]) when averaged across participants, as well as at the individual level using hierarchical modeling. Our results provide support for the assumption that Bayesian belief updating operates as a stable characteristic in perceptual decision-making. We discuss the utility and applicability of reliable perceptual decision-making paradigms as a measure of individual differences in the general population, as well as a diagnostic tool in psychiatric research.

Reconceptualizing complex posttraumatic stress disorder: A predictive processing framework for mechanisms and intervention

In this article, we introduce a framework for interpreting Complex Posttraumatic Stress Disorder (C-PTSD) through predictive processing, a neuroscience concept explaining the brain's interpretation and prediction of sensory information. While closely related to PTSD, C-PTSD encompasses additional symptom clusters marked by disturbances in self-organization (DSO), such as negative self-concept, affect dysregulation, and relational difficulties, typically resulting from prolonged traumatic stressors. Our model leverages advances in computational psychiatry and neuroscience, offering a mechanistic explanation for these symptoms by illustrating how prolonged trauma disrupts the brain's predictive processing. Specifically, altered predictive mechanisms contribute to C-PTSD's symptomatology, focusing on DSO: (1) Negative self-concept emerges from maladaptive priors that bias perception towards self-criticism, misaligning expected and actual interoceptive states; (2) Misalignment between predicted and actual interoceptive signals leads to affect dysregulation, with sensitivity to bodily cues; and (3) Relationship challenges arise from skewed social prediction errors, fostering mistrust and withdrawal. This precision-focused approach sheds light on the dynamics underpinning C-PTSD and highlights potential intervention targets aimed at recalibrating the predictive processing system.

Understanding music and aging through the lens of Bayesian inference

Bayesian inference has recently gained momentum in explaining music perception and aging. A fundamental mechanism underlying Bayesian inference is the notion of prediction. This framework could explain how predictions pertaining to musical (melodic, rhythmic, harmonic) structures engender action, emotion, and learning, expanding related concepts of music research, such as musical expectancies, groove, pleasure, and tension. Moreover, a Bayesian perspective of music perception may shed new insights on the beneficial effects of music in aging. Aging could be framed as an optimization process of Bayesian inference. As predictive inferences refine over time, the reliance on consolidated priors increases, while the updating of prior models through Bayesian inference attenuates. This may affect the ability of older adults to estimate uncertainties in their environment, limiting their cognitive and behavioral repertoire. With Bayesian inference as an overarching framework, this review synthesizes the literature on predictive inferences in music and aging, and details how music could be a promising tool in preventive and rehabilitative interventions for older adults through the lens of Bayesian inference.

Understanding Cognitive Behavioral Therapy for Psychosis Through the Predictive Coding Framework

Psychological treatments for persecutory delusions, particularly cognitive behavioral therapy for psychosis, are efficacious; however, mechanistic theories explaining why they work rarely bridge to the level of cognitive neuroscience. Predictive coding, a general brain processing theory rooted in cognitive and computational neuroscience, has increasing experimental support for explaining symptoms of psychosis, including the formation and maintenance of delusions. Here, we describe recent advances in cognitive behavioral therapy for psychosis-based psychotherapy for persecutory delusions, which targets specific psychological processes at the computational level of information processing. We outline how Bayesian learning models employed in predictive coding are superior to simple associative learning models for understanding the impact of cognitive behavioral interventions at the algorithmic level. We review hierarchical predictive coding as an account of belief updating rooted in prediction error signaling. We examine how this process is abnormal in psychotic disorders, garnering noisy sensory data that is made sense of through the development of overly strong delusional priors. We argue that effective cognitive behavioral therapy for psychosis systematically targets the way sensory data are selected, experienced, and interpreted, thus allowing for the strengthening of alternative beliefs. Finally, future directions based on these arguments are discussed.

Can computational models help elucidate the link between complex trauma and hallucinations?

Recently, a number of predictive coding models have been proposed to account for post-traumatic stress disorder (PTSD)'s symptomatology, including intrusions, flashbacks and hallucinations. These models were usually developed to account for traditional/type-1 PTSD. We here discuss whether these models also apply or can be translated to the case of complex/type-2 PTSD and childhood trauma (cPTSD). The distinction between PTSD and cPTSD is important because the disorders differ in terms of symptomatology and potential mechanisms, how they relate to developmental stages, but also in terms of illness trajectory and treatment. Models of complex trauma could give us insights on hallucinations in physiological/pathological conditions or more generally on the development of intrusive experiences across diagnostic classes.

Interactive relationship between alexithymia, psychological distress and posttraumatic stress disorder symptomology across time

Alexithymia, psychological distress, and posttraumatic stress disorder (PTSD) are highly related constructs. The ongoing debate about the nature and relationship between these constructs is perpetuated by an overreliance on cross-sectional research. We examined the longitudinal interactive relationship between alexithymia, psychological distress, and PTSD. We hypothesised that there is an interactive relationship between the three constructs. Military personnel (N = 1871) completed the Toronto Alexithymia Scale, the Kessler 10 and a PTSD Checklist (PCL-C) at pre-deployment, post-deployment, and at 3-4 years following the post-deployment assessment. We initially tested whether psychological distress is either a moderator or mediator in the relationship between alexithymia and PTSD across the time points. General psychological distress was a partial mediator of total PTSD severity and hyperarousal symptomology at all three time points. Psychological distress fully mediated re-experiencing and avoidance symptomology at all three time points. Our results suggest that those with alexithymia are at longitudinal risk of developing more severe PTSD symptomology and experiencing hyperarousal irrespective of temporal proximity to traumatic exposure. Further, vulnerability to the emergence of re-experiencing and avoidance symptomology for those with alexithymia is increased when one experiences greater distress. Our results show that alexithymia is a persistent risk factor for PTSD symptomology.

Posttraumatic reexperiencing and alcohol use: mediofrontal theta as a neural mechanism for negative reinforcement

Objective

Over half of US military veterans with posttraumatic stress disorder (PTSD) use alcohol heavily, potentially to cope with their symptoms. This study investigated the neural underpinnings of PTSD symptoms and heavy drinking in veterans. We focused on brain responses to salient outcomes within predictive coding theory. This framework suggests the brain generates prediction errors (PEs) when outcomes deviate from expectations. Alcohol use might provide negative reinforcement by reducing the salience of negatively-valenced PEs and dampening experiences like loss.

Methods

We analyzed electroencephalography (EEG) responses to unpredictable gain/loss feedback in veterans of Operations Enduring and Iraqi Freedom. We used time-frequency principal components analysis of event-related potentials to isolate neural responses indicative of PEs, identifying mediofrontal theta linked to losses (feedback-related negativity, FRN) and central delta associated with gains (reward positivity, RewP).

Results

Intrusive reexperiencing symptoms of PTSD were associated with intensified mediofrontal theta signaling during losses, suggesting heightened negative PE sensitivity. Conversely, increased hazardous alcohol use was associated with reduced theta responses, implying a dampening of these negative PEs. The separate delta-RewP component showed associations with alcohol use but not PTSD symptoms.

Conclusions

Findings suggest a common neural component of PTSD and hazardous alcohol use involving altered PE processing. We suggest that reexperiencing enhances the intensity of salient negative PEs, while chronic alcohol use may reduce their intensity, thereby providing negative reinforcement by muting emotional disruption from reexperienced trauma. Modifying the mediofrontal theta response could address the intertwined nature of PTSD symptoms and alcohol use, providing new avenues for treatment.

The multisensory mind: a systematic review of multisensory integration processing in Anorexia and Bulimia Nervosa

Individuals with Anorexia Nervosa and Bulimia Nervosa present alterations in the way they experience their bodies. Body experience results from a multisensory integration process in which information from different sensory domains and spatial reference frames is combined into a coherent percept. Given the critical role of the body in the onset and maintenance of both Anorexia Nervosa and Bulimia Nervosa, we conducted a systematic review to examine multisensory integration abilities of individuals affected by these two conditions and investigate whether they exhibit impairments in crossmodal integration. We searched for studies evaluating crossmodal integration in individuals with a current diagnosis of Anorexia Nervosa and Bulimia Nervosa as compared to healthy individuals from both behavioral and neurobiological perspectives. A search of PubMed, PsycINFO, and Web of Sciences databases was performed to extract relevant articles. Of the 2348 studies retrieved, 911 were unique articles. After the screening, 13 articles were included. Studies revealed multisensory integration abnormalities in patients affected by Anorexia Nervosa; only one included individuals with Bulimia Nervosa and observed less severe impairments compared to healthy controls. Overall, results seemed to support the presence of multisensory deficits in Anorexia Nervosa, especially when integrating interoceptive and exteroceptive information. We proposed the Predictive Coding framework for understanding our findings and suggested future lines of investigation.

Mental health meets computational neuroscience: A predictive Bayesian account of the relationship between interoception and multisensory bodily illusions in anorexia nervosa

Mental health disorders pose a significant challenge to society. The Bayesian perspective on the mind offers unique insights and tools that may help address a variety of mental health conditions. Psychopathological dysfunctions are often connected to altered predictive and active inference processes, in which cognitive and physiological pathogenic beliefs shape the clinical condition and its symptoms. However, there is a lack of general empirical models that integrate cognitive beliefs, physiological experience, and symptoms in healthy and clinical populations. In this study, we examined the relationship between altered predictive mechanisms, interoception, and pathological bodily distortions in healty individuals and in individuals suffering from anorexia nervosa (AN). AN patients (N=15) completed a Virtual Reality Full-Body Illusion along with interoceptive tasks twice: at hospital admission during an acute symptomatological phase (Time 1) and after a 12-week outpatient clinical weight-restoring rehabilitative program (Time 2). Results were compared to a healthy control group. Our findings indicated that higher levels of interoceptive metacognitive awareness were associated with a greater embodiment. However, unlike in healthy participants, AN patients' interoceptive metacognition was linked to embodiment even in multisensory mismatching (asynchronous) conditions. In addition, unlike in healthy participants, higher interoceptive metacognition in AN patients was related to prior abnormal bodily distortions during the acute symptomatology phase. Prediction errors in bodily estimates predicted posterior bodily estimate distortions after the illusion, but while this relationship was only significant in the synchronous condition in healthy participants, there was no significant difference between synchronous and asynchronous conditions in AN patients. Despite the success of the rehabilitation program in restoring some dysfunctional patterns in the AN group, prediction errors and posterior estimate distortions were present at hospital discharge. Our findings suggest that individuals with AN prioritize interoceptive metacognitive processes (i.e., confidence in their own perceived sensations rather than their actual perceptions), disregarding bottom-up bodily inputs in favour of their prior altered top-down beliefs. Moreover, even if the rehabilitative program partially mitigated these alterations, the pathological condition impaired the patients' ability to coherently update their prior erroneous expectations with real-time multisensory bottom-up bodily information, possibly locking the patients in the experience of a distorted prior top-down belief. These results suggest new therapeutic perspectives and introduce the framework of regenerative virtual therapy (RVT), which aims at utilizing technology-based somatic modification techniques to restructure the maladaptive priors underlying a pathological condition.

The influence of aerobic exercise on model-based decision making in women with posttraumatic stress disorder

Individuals with PTSD often exhibit deficits in executive functioning. An unexplored aspect of neurocognitive functions associated with PTSD is the type of learning system engaged in during decision-making. A model-free (MF) system is habitual in nature and involves trial-and-error learning that is often updated based on the most recent experience (e.g., repeat action if rewarded). A model-based (MB) system is goal-directed in nature and involves the development of an abstract representation of the environment to facilitate decisions (e.g., choose sequence of actions according to current contextual state and predicted outcomes). The existing neurocognitive literature on PTSD suggests the hypothesis of greater reliance on MF vs MB learning strategies when navigating their environment. While MF systems may be more cognitively efficient, they do not afford flexibility when making prospective predictions about likely outcomes of different decision-tree branches. Emerging research suggests that an acute bout of aerobic exercise improves certain aspects of neurocognition, and thereby could promote the utilization of MB over MF systems during decision making, although prior research has not yet tested this hypothesis. Accordingly, the current study administered a lab-based two-stage Markov decision-making task capable of discriminating MF vs MB decision making, in order to determine if moderate-intensity aerobic exercise (either shortly after or 30-minutes after the exercise bout has ended) promotes greater engagement in MB behavioral strategies compared to light-intensity aerobic exercise in adult women with and without PTSD (N=61). Results revealed that control women generally displayed higher levels of MB behavior that was further increased following immediate exercise, particularly moderate-intensity exercise. By contrast, the PTSD group generally displayed lower levels of MB behavior, and exhibited greater MB behavior when completing the task following moderate-intensity aerobic exercise compared to light-intensity aerobic exercise regardless of whether there was a short or long delay between exercise and the task. Additionally, women with PTSD demonstrated less impairment in MB decision-making compared to controls following moderate-intensity aerobic exercise. These results suggest that an acute bout of moderate-intensity aerobic exercise boosts MB behavior in women with PTSD, and suggests that aerobic exercise may play an important role in enhancing cognitive outcomes for PTSD.