Reward and avoidance learning in the context of aversive environments and possible implications for depressive symptoms

Childhood adversity and mind wandering: the mediating role of cognitive flexibility and habitual tendencies

ABSTRACTBackground: Initial evidence proposes that exposure to childhood adversity may induce avoidance or withdrawal behaviour. However, it remains unclear whether childhood adversity results in avoidance from externally directed thinking to both deliberate and spontaneous mind wandering, i.e. intentionally or unintentionally diverting attention from ongoing task to task-independent thoughts.Objective: To assess the associations between childhood adversity, and mind wandering, and to evaluate the mediating roles of cognitive flexibility, and habit tendencies.Methods: A total of 601 Chinese subjects (378 females, Mage = 19.37) participated in the current study. The participants completed a series of questionnaires including demographics, childhood maltreatment, cognitive flexibility, habitual tendencies, and mind wandering.Results: Hierarchical regression analyses showed childhood adversity, the control facet of cognitive flexibility, and the automaticity facet of habitual tendencies had significant contributions to deliberate mind wandering (β = 0.10, β = -0.40, and β = 0.06) and spontaneous mind wandering (β = 0.09, β = -0.28, and β = 0.07). Serial mediation analyses revealed that the control and automaticity partially mediated associations between childhood adversity and mind wandering (deliberate mind wandering: 95% CIs = [0.037 0.078], and spontaneous mind wandering: 95% CIs = [0.023, 0.062]).Conclusions: The findings underscore the pivotal role of mediators in delineating the relationship between childhood adversity and mind wandering in everyday life. Interventions geared toward augmenting the control component of cognitive flexibility and regulating the automatic component of habitual tendencies show the potential to ameliorate the propensity of individuals affected by childhood adversity to disengage cognitively from the present moment.

Modelling the structure and evolution of cultural information as quasispecies

We present a novel mode of cultural evolution whereby some forms of transmission may be modelled as quasispecies. The model incorporates the effect of high rates of error in certain forms of communication; while also building on the structural similarities between biological molecules and written language. Firstly, both written language and key biological molecules, such as RNA and proteins, are modular. Within these molecules, structural domains may be recombined, while retaining their function. Likewise, sentences are structured as combinations of clauses, in which each clause contains a domain of information. The clausal structure permits the recombination of information to adopt different meanings, while allowing each unit to retain its identity. Secondly, by virtue of intrinsically-high error rates, we show that some, but not all, aspects of communicated culture information exists as rapidly evolving clouds within the population. These clouds of cultural information behave as quasispecies, which we model with varying mutation rates and suitable selection coefficients. We then integrate these ideas with the application of Shannon Diversity Index to produce a more holistic view of culture that is centred on the evolution of its information. Re-imagining culture, as evolving clouds of information, unifies the mode in which information is stored culturally and biologically, and opens up new avenues of comparative analysis.

Computational perspectives on human fear and anxiety

Fear and anxiety are adaptive emotions that serve important defensive functions, yet in excess, they can be debilitating and lead to poor mental health. Computational modelling of behaviour provides a mechanistic framework for understanding the cognitive and neurobiological bases of fear and anxiety, and has seen increasing interest in the field. In this brief review, we discuss recent developments in the computational modelling of human fear and anxiety. Firstly, we describe various reinforcement learning strategies that humans employ when learning to predict or avoid threat, and how these relate to symptoms of fear and anxiety. Secondly, we discuss initial efforts to explore, through a computational lens, approach-avoidance conflict paradigms that are popular in animal research to measure fear- and anxiety-relevant behaviours. Finally, we discuss negative biases in decision-making in the face of uncertainty in anxiety.

Pavlovian-to-Instrumental Transfer across Mental Disorders: A Review

A mechanism known as Pavlovian-to-instrumental transfer (PIT) describes a phenomenon by which the values of environmental cues acquired through Pavlovian conditioning can motivate instrumental behavior. PIT may be one basic mechanism of action control that can characterize mental disorders on a dimensional level beyond current classification systems. Therefore, we review human PIT studies investigating subclinical and clinical mental syndromes. The literature prevails an inhomogeneous picture concerning PIT. While enhanced PIT effects seem to be present in non-substance-related disorders, overweight people, and most studies with AUD patients, no altered PIT effects were reported in tobacco use disorder and obesity. Regarding AUD and relapsing alcohol-dependent patients, there is mixed evidence of enhanced or no PIT effects. Additionally, there is evidence for aberrant corticostriatal activation and genetic risk, e.g., in association with high-risk alcohol consumption and relapse after alcohol detoxification. In patients with anorexia nervosa, stronger PIT effects elicited by low caloric stimuli were associated with increased disease severity. In patients with depression, enhanced aversive PIT effects and a loss of action-specificity associated with poorer treatment outcomes were reported. Schizophrenic patients showed disrupted specific but intact general PIT effects. Patients with chronic back pain showed reduced PIT effects. We provide possible reasons to understand heterogeneity in PIT effects within and across mental disorders. Further, we strengthen the importance of reliable experimental tasks and provide test-retest data of a PIT task showing moderate to good reliability. Finally, we point toward stress as a possible underlying factor that may explain stronger PIT effects in mental disorders, as there is some evidence that stress per se interacts with the impact of environmental cues on behavior by selectively increasing cue-triggered wanting. To conclude, we discuss the results of the literature review in the light of Research Domain Criteria, suggesting future studies that comprehensively assess PIT across psychopathological dimensions.

Model-based prioritization for acquiring protection

Protection often involves the capacity to prospectively plan the actions needed to mitigate harm. The computational architecture of decisions involving protection remains unclear, as well as whether these decisions differ from other beneficial prospective actions such as reward acquisition. Here we compare protection acquisition to reward acquisition and punishment avoidance to examine overlapping and distinct features across the three action types. Protection acquisition is positively valenced similar to reward. For both protection and reward, the more the actor gains, the more benefit. However, reward and protection occur in different contexts, with protection existing in aversive contexts. Punishment avoidance also occurs in aversive contexts, but differs from protection because punishment is negatively valenced and motivates avoidance. Across three independent studies (Total N = 600) we applied computational modeling to examine model-based reinforcement learning for protection, reward, and punishment in humans. Decisions motivated by acquiring protection evoked a higher degree of model-based control than acquiring reward or avoiding punishment, with no significant differences in learning rate. The context-valence asymmetry characteristic of protection increased deployment of flexible decision strategies, suggesting model-based control depends on the context in which outcomes are encountered as well as the valence of the outcome.

Stronger Prejudices Are Associated With Decreased Model-Based Control

Background: Prejudices against minorities can be understood as habitually negative evaluations that are kept in spite of evidence to the contrary. Therefore, individuals with strong prejudices might be dominated by habitual or "automatic" reactions at the expense of more controlled reactions. Computational theories suggest individual differences in the balance between habitual/model-free and deliberative/model-based decision-making. Methods: 127 subjects performed the two Step task and completed the blatant and subtle prejudice scale. Results: By using analyses of choices and reaction times in combination with computational modeling, subjects with stronger blatant prejudices showed a shift away from model-based control. There was no association between these decision-making processes and subtle prejudices. Conclusion: These results support the idea that blatant prejudices toward minorities are related to a relative dominance of habitual decision-making. This finding has important implications for developing interventions that target to change prejudices across societies.

Mechanisms Underlying Unconscious Processing and Their Alterations in Post-traumatic Stress Disorder: Neuroimaging of Zero Monetary Outcomes Contextually Framed as "No Losses" vs. "No Gains"

Although unconscious processing is a key element of mental operation, its neural correlates have not been established. Also, clinical observations suggest that unconscious processing may be involved in the pathophysiology of post-traumatic stress disorder (PTSD), but the neurobiological mechanisms underlying such impairments remain unknown. The purpose of the present study was to examine putative mechanisms underlying unconscious processing by healthy participants and to determine whether these mechanisms may be altered in PTSD patients. Twenty patients with PTSD and 27 healthy individuals were administered a validated wheel of fortune-type gambling task during functional magnetic resonance imaging (fMRI). Unconscious processing was elicited using unconscious contextual framing of the zero monetary outcomes as "no loss," "no gain" or as "neutral." Brief passive visual processing of the "no loss" vs. "no gain" contrast by healthy participants yielded bilateral frontal-, temporal- and insular cortices and striatal activations. Between-group comparison revealed smaller activity in the left anterior prefrontal-, left dorsolateral prefrontal-, right temporal- and right insular cortices and in bilateral striatum in PTSD patients with the left dorsolateral prefrontal cortex activity been more pronounced in those with greater PTSD severity. These observations implicate frontal-, temporal-, and insular cortices along with the striatum in the putative mechanisms underlying unconscious processing of the monetary outcomes. Additionally, our results support the hypothesis that PTSD is associated with primary cortical and subcortical alterations involved in the above processes and that these alterations may be related to some aspects of PTSD symptomatology.