Same Same, But Different: Brain Areas Underlying the Learning from Repetitive Episodic Prediction Errors.

Prediction errors (PEs) function as learning signals. It is yet unclear how varying compared to repetitive PEs affect episodic memory in brain and behavior. The current study investigated cerebral and behavioral effects of experiencing either multiple alternative versions ("varying") or one single alternative version ("repetitive") of a previously encoded episode. Participants encoded a set of episodes ("originals") by watching videos showing toy stories. During scanning, participants either experienced originals, one single or multiple alternative versions of the previously encoded episodes. Participants' memory performance was tested through recall of original objects. Varying and repetitive PEs revealed typical brain responses to the detection of mismatching information including inferior frontal and posterior parietal regions, as well as hippocampus, which is further linked to memory reactivation, and the amygdala, known for modulating memory consolidation. Furthermore, experiencing varying and repetitive PEs triggered distinct brain areas as revealed by direct contrast. Among others, experiencing varying versions triggered activity in the caudate, a region that has been associated with PEs. In contrast, repetitive PEs activated brain areas that resembled more those for retrieval of originally encoded episodes. Thus, ACC and posterior cingulate cortex activation seemed to serve both reactivating old and integrating new but similar information in episodic memory. Consistent with neural findings, participants recalled original objects less accurately when only presented with the same, but not varying, PE during fMRI. The current findings suggest that repeated PEs interact more strongly with a recalled original episodic memory than varying PEs.

Action Segmentation in the Brain: The Role of Object-Action Associations.

Motion information has been argued to be central to the subjective segmentation of observed actions. Concerning object-directed actions, object-associated action information might as well inform efficient action segmentation and prediction. The present study compared the segmentation and neural processing of object manipulations and equivalent dough ball manipulations to elucidate the effect of object-action associations. Behavioral data corroborated that objective relational changes in the form of (un-)touchings of objects, hand, and ground represent meaningful anchor points in subjective action segmentation rendering them objective marks of meaningful event boundaries. As expected, segmentation behavior became even more systematic for the weakly informative dough. fMRI data were modeled by critical subjective, and computer-vision-derived objective event boundaries. Whole-brain as well as planned ROI analyses showed that object information had significant effects on how the brain processes these boundaries. This was especially pronounced at untouchings, that is, events that announced the beginning of the upcoming action and might be the point where competing predictions are aligned with perceptual input to update the current action model. As expected, weak object-action associations at untouching events were accompanied by increased biological motion processing, whereas strong object-action associations came with an increased contextual associative information processing, as indicated by increased parahippocampal activity. Interestingly, anterior inferior parietal lobule activity increased for weak object-action associations at untouching events, presumably because of an unrestricted number of candidate actions for dough manipulation. Our findings offer new insights into the significance of objects for the segmentation of action.

Updating predictions in a complex repertoire of actions and its neural representation.

Even though actions we observe in everyday life seem to unfold in a continuous manner, they are automatically divided into meaningful chunks, that are single actions or segments, which provide information for the formation and updating of internal predictive models. Specifically, boundaries between actions constitute a hub for predictive processing since the prediction of the current action comes to an end and calls for updating of predictions for the next action. In the current study, we investigated neural processes which characterize such boundaries using a repertoire of complex action sequences with a predefined probabilistic structure. Action sequences consisted of actions that started with the hand touching an object (T) and ended with the hand releasing the object (U). These action boundaries were determined using an automatic computer vision algorithm. Participants trained all action sequences by imitating demo videos. Subsequently, they returned for an fMRI session during which the original action sequences were presented in addition to slightly modified versions thereof. Participants completed a post-fMRI memory test to assess the retention of original action sequences. The exchange of individual actions, and thus a violation of action prediction, resulted in increased activation of the action observation network and the anterior insula. At U events, marking the end of an action, increased brain activation in supplementary motor area, striatum, and lingual gyrus was indicative of the retrieval of the previously encoded action repertoire. As expected, brain activation at U events also reflected the predefined probabilistic branching structure of the action repertoire. At T events, marking the beginning of the next action, midline and hippocampal regions were recruited, reflecting the selected prediction of the unfolding action segment. In conclusion, our findings contribute to a better understanding of the various cerebral processes characterizing prediction during the observation of complex action repertoires.

The significance of structural rich club hubs for the processing of hierarchical stimuli.

The brain's structural network follows a hierarchy that is described as rich club (RC) organization, with RC hubs forming the well-interconnected top of this hierarchy. In this study, we tested whether RC hubs are involved in the processing of hierarchically higher structures in stimulus sequences. Moreover, we explored the role of previously suggested cortical gradients along anterior-posterior and medial-lateral axes throughout the frontal cortex. To this end, we conducted a functional magnetic resonance imaging (fMRI) experiment and presented participants with blocks of digit sequences that were structured on different hierarchically nested levels. We additionally collected diffusion weighted imaging data of the same subjects to identify RC hubs. This classification then served as the basis for a region of interest analysis of the fMRI data. Moreover, we determined structural network centrality measures in areas that were found as activation clusters in the whole-brain fMRI analysis. Our findings support the previously found anterior and medial shift for processing hierarchically higher structures of stimuli. Additionally, we found that the processing of hierarchically higher structures of the stimulus structure engages RC hubs more than for lower levels. Areas involved in the functional processing of hierarchically higher structures were also more likely to be part of the structural RC and were furthermore more central to the structural network. In summary, our results highlight the potential role of the structural RC organization in shaping the cortical processing hierarchy.

Gray matter matters: Cognitive stability and flexibility in schizophrenia spectrum disorder.

Cognitive dysfunction constitutes a core characteristic of schizophrenia spectrum disorders (SZ). Specifically, deficits in updating generative models (i.e., cognitive flexibility) and shielding against distractions (i.e., cognitive stability) are considered critical contributors to cognitive impairment in these patients. Here, we examined the structural integrity of frontostriatal networks and their associations with reduced cognitive stability and flexibility in SZ patients. In a sample of 21 patients diagnosed with SZ and 22 healthy controls, we measured gray matter volume (GMV) using structural MRI. Further, cognitive stability and flexibility were assessed using a switch-drift paradigm, quantifying the successful ignoring of distracters and detection of rule switches. Compared to controls, patients showed significantly smaller GMV in the whole brain and three predefined regions of interest: the medial prefrontal cortex (mPFC), inferior frontal gyrus (IFG), and caudate nucleus (CN). Notably, GMV in these areas positively correlated with correct rule-switch detection but not with ignoring rule-compatible drifts. Further, the volumetric differences between SZ patients and controls were statistically explainable by considering the behavioral performance in the switch-drift task. Our results indicate that morphological abnormalities in frontostriatal networks are associated with deficient flexibility in SZ patients and highlight the necessity of minimizing neurodevelopmental and progressive brain atrophy in this population.

Neural correlates of changing food choices while bypassing values.

Current theories suggest that altering choices requires value modification. To investigate this, normal-weight female participants' food choices and values were tested before and after an approach-avoidance training (AAT), while neural activity was recorded during the choice task using functional magnetic resonance imaging (fMRI). During AAT, participants consistently approached low- while avoiding high-calorie food cues. AAT facilitated low-calorie food choices, leaving food values unchanged. Instead, we observed a shift in indifference points, indicating the decreased contribution of food values in food choices. Training-induced choice shifts were associated with increased activity in the posterior cingulate cortex (PCC). In contrast, the medial PFC activity was not changed. Additionally, PCC gray matter density predicted individual differences in training-induced functional changes, suggesting anatomic predispositions to training impact. Our findings demonstrate neural mechanisms underlying choice modulation independent of valuation-related processes, which has substantial theoretical significance for decision-making frameworks and translational implications for health-related decisions resilient to value shifts.

Can hypnotic susceptibility be explained by bifactor models? Structural equation modeling of the Harvard group scale of hypnotic susceptibility - Form A.

Individuals differ in their responsiveness to hypnotic suggestions. However, defining and measuring hypnotizability is contentious because standardized scales, such as the Harvard group scale (HGSHS:A), measure a mixture of general suggestibility and its alteration due to hypnotic induction (hypnotizability). Exploratory factor analyses (FA) of standardized scales indicated their multidimensionality; however, the number and nature of latent factors are debated. We applied Confirmatory FA to the HGSHS:A scores of 477 volunteers and tested several theory-driven models. Scores were best explained by a bifactor model consisting of a G-factor and three correlated minor factors. The presented bifactor model shows that two sources of variability affect HGSHS:A simultaneously. Structural equation modeling revealed that the challenge-ideomotor factor predicts the other two minor factors, implying these suggestions might require more fundamental processes than other types. These results demonstrate the multifaceted and bifactorial structure of hypnotic suggestibility and underscore the desideratum for developing more differentiated scales.

Modification of food preferences by posthypnotic suggestions: An event-related brain potential study.

The preference for high-over low-calorie food and difficulties in inhibiting the desire for high-calorie food are important factors involved in unhealthy food choices. Here, we explored posthypnotic suggestions (PHS), aiming to increase the desire for vegetables and fruits, as a possible new tool to induce a preference for low-calorie food. Following the termination of hypnosis, PHS was activated and deactivated in counterbalanced order, while event-related brain-potentials were recorded. Two tasks were administered, a food-face classification measuring implicit food preferences, where stimuli were categorized as showing food items or faces, and a Go-NoGo task measuring inhibition, where food items were selected as being appropriate for making a salad or not. In the food-face classification task without PHS, the early visual P1 component, a marker of stimulus reward-associations, was larger in response to high-than low-calorie food pictures; PHS eliminated this difference. PHS also yielded faster RTs and larger amplitudes of a late positive component in low-versus high-calorie items. Hence, PHS appeared to neutralize the positive perceptual bias toward high-calorie food items and enhance the effective processing of low-calorie items by increasing motivated attention. In the Go-NoGo task, PHS decreased the NoGo-N2; PHS increased the early Go- and NoGo-P3, possibly by turning low- and high-calorie items more pleasant and unpleasant, respectively, requiring more proactive control to inhibit task-irrelevant food-related emotions. Further, in the Go condition, PHS quickened the rejection of salad-inappropriate high-calorie items and increased the amplitude of late-P3, indicating facilitated classification of high-calorie items and increased response monitoring. Together, PHS effectively increased the preference for low-calorie food and the inhibition of impulses toward high-calorie food; therefore, PHS may be a promising tool for supporting healthy and sustainable food choices.

Cognitive simulation along with neural adaptation explain effects of suggestions: a novel theoretical framework.

Hypnosis is an effective intervention with proven efficacy that is employed in clinical settings and for investigating various cognitive processes. Despite their practical success, no consensus exists regarding the mechanisms underlying well-established hypnotic phenomena. Here, we suggest a new framework called the Simulation-Adaptation Theory of Hypnosis (SATH). SATH expands the predictive coding framework by focusing on (a) redundancy elimination in generative models using intrinsically generated prediction errors, (b) adaptation due to amplified or prolonged neural activity, and (c) using internally generated predictions as a venue for learning new associations. The core of our treatise is that simulating proprioceptive, interoceptive, and exteroceptive signals, along with the top-down attenuation of the precision of sensory prediction errors due to neural adaptation, can explain objective and subjective hypnotic phenomena. Based on these postulations, we offer mechanistic explanations for critical categories of direct verbal suggestions, including (1) direct-ideomotor, (2) challenge-ideomotor, (3) perceptual, and (4) cognitive suggestions. Notably, we argue that besides explaining objective responses, SATH accounts for the subjective effects of suggestions, i.e., the change in the sense of agency and reality. Finally, we discuss individual differences in hypnotizability and how SATH accommodates them. We believe that SATH is exhaustive and parsimonious in its scope, can explain a wide range of hypnotic phenomena without contradiction, and provides a host of testable predictions for future research.

Childhood trauma and violent behavior in adolescents are differentially related to cognitive-emotional deficits.

Introduction: Converging neurobiological and epidemiological evidence indicates that exposure to traumatic events in the early stages of development, that is, adverse childhood experiences (ACEs), negatively affects the likelihood of being involved in violent behavior later in life. These problems are hypothesized to be mediated by the disruption of executive functions, in particular, the ability to inhibit inappropriate actions. Here we aimed to distinguish the contribution of inhibition in non-emotional and emotional situations (i.e., emotion regulation) and assessed the modulating influence of stress, testing Nairobi county high school students in a two-experiment study. Methods: In Experiment 1, neutral and emotional inhibition, working memory, and fluid intelligence were measured alongside questionnaires about ACE and violent behavior. Experiment 2 replicated these relations in an independent sample and assessed whether they would be aggravated after acute experimentally induced stress. Results: Experiment 1 results showed that ACE was positively related to both non-emotional and emotional inhibition; in contrast, violent behavior was only associated with deficient emotional inhibition. Experiment 2 findings showed that stress did not significantly affect the relation of ACE to non-emotional inhibition and emotion regulation; however, it increased deficits of violent participants in their ability to down-regulate emotions. Discussion: Together, results suggest that deficits in emotion regulation, especially under stressful conditions, are more critical than impairments in non-emotional inhibition in predicting violent behavior in victims of childhood trauma. These findings open perspectives toward more targeted research and interventions.

The response set theory of hypnosis reconsidered: toward an integrative model.

Irving Kirsch is a leading figure in the field of psychological science who has advanced our understanding of hypnosis in key respects that have withstood the tests of time and replication. We honor his prodigious contributions over his distinguished career and extend his response expectancy theory in an integrative model that encompasses predictive coding. We review the construct of expectancies that he articulated and championed for decades and extended in response set theory. We propose novel hypotheses to align his innovative contributions with the most current findings in psychological science and to acknowledge the heuristic value of his work. We especially focus on (I) how the response set theory can be conceptualized in terms of the predictive coding model and (II) psycho-social constructs that need to be considered to better understand the effects of expectancies on hypnotic phenomena in an open and evidence-based integrative model of hypnosis.

The nature and persistence of the effects of posthypnotic suggestions on food preferences: The final report of an online study.

The persistence of food preferences, which are crucial for diet-related decisions, is a significant obstacle to changing unhealthy eating behavior. To overcome this obstacle, the current study investigates whether posthypnotic suggestions (PHSs) can enhance food-related decisions by measuring food choices and subjective ratings. After assessing hypnotic susceptibility in Session 1, at the beginning of Session 2, a PHS was delivered aiming to increase the desirability of healthy food items (e.g., vegetables and fruit). After the termination of hypnosis, a set of two tasks was administrated twice, once when the PHS was activated and once deactivated in counterbalanced order. The task set consisted of rating 170 pictures of food items, followed by an online supermarket where participants were instructed to select enough food from the same item pool for a fictitious week of quarantine. After 1 week, Session 3 mimicked Session 2 without renewed hypnosis induction to assess the persistence of the PHS effects. The Bayesian hierarchical modeling results indicate that the PHS increased preferences and choices of healthy food items without altering the influence of preferences in choices. In contrast, for unhealthy food items, not only both preferences and choices were decreased due to the PHS, but also their relationship was modified. That is, although choices became negatively biased against unhealthy items, preferences played a more dominant role in unhealthy choices when the PHS was activated. Importantly, all effects persisted over 1 week, qualitatively and quantitatively. Our results indicate that although the PHS affected healthy choices through resolve, i.e., preferred more and chosen more, unhealthy items were probably chosen less impulsively through effortful suppression. Together, besides the translational importance of the current results for helping the obesity epidemic in modern societies, our results contribute theoretically to the understanding of hypnosis and food choices.

The Nature and Persistence of Posthypnotic Suggestions' Effects on Food Preferences: An Online Study.

Food preferences are crucial for diet-related decisions, which substantially impact individual health and global climate. However, the persistence of unfavorable food preferences is a significant obstacle to changing eating behavior. Here we explored the effects of posthypnotic suggestions (PHS) on food-related decisions by measuring food choices, subjective ratings, and indifference points. In Session 1, demographic data and hypnotic susceptibility of participants were assessed. In Session 2, following hypnosis induction, PHS aiming to increase the desirability of healthy food was delivered. Afterward, a task set was administrated twice, once when PHS was activated and once deactivated. The order of PHS activation was counterbalanced across participants. The task set included a liking-rating task for 170 pictures of different food items, followed by an online supermarket where participants were instructed to select enough food for a fictitious week of quarantining from the same item pool. After 1 week, Session 3 repeated Session 2 without hypnosis induction in order to assess the persistence of PHS. The crucial dependent measures were food choices, subjective ratings, and the indifference points as a function of time and PHS condition.

Can posthypnotic suggestions boost updating in working memory? Behavioral and ERP evidence.

Updating is an essential executive function (EF), responsible for storing, retrieving, and substituting information in working memory (WM). Here we investigated whether posthypnotic suggestions (PHS) given to high-hypnotizable participants can enhance updating in WM and measured neural correlates of the observed effects by recording event-related brain potentials (ERP). In a tone-monitoring task different syllables were presented in random order, requiring a response to every fourth presentation of a given syllable. Experiment 1 (n = 19) established the relationship between performance and several ERP components across updating load (different numbers of syllables). In Experiment 2 (n = 18), a no-hypnosis (NH) and a hypnosis-plus-PHS session were administrated in counterbalanced order. Task instructions, presented at the beginning of the sessions, emphasized a cognitive strategy, demanding imagination of visual counters, a strategy that was also emphasized during PHS. PHS additionally contained suggestions stimulating cognitive simulation of the task, where participants were advised to apply the suggested strategy. Relative to the NH session, PHS enhanced WM performance with medium to large effect sizes. In ERPs, PHS increased the P2 and P3 components, indicating the proactive recruitment of control-related attention and updating-related cognitive control processes, respectively. PHS also reduced updating load effects in the posterior recognition component, suggesting diminished demands on WM buffers. These ERP findings suggest that PHS enhanced updating in WM by strengthening proactive control, which may have diminished the necessity for reactive control. Hence, the present results suggest that our PHS had worked like mental practice helping participants to develop an efficient and context-dependent trigger-action contingency. Consequentially, the present study provides a new framework for employing PHSs, which may be used as a basis for developing new training regimes for modifying WM or other EFs.

Common and specific loci of Stroop effects in vocal and manual tasks, revealed by event-related brain potentials and posthypnotic suggestions.

In the Stroop task color words are shown in various print colors. When print colors are named or classified with button presses, interference occurs if word meaning is color-incongruent and facilitation if it is congruent. Although the Stroop effects in vocal and manual task versions are similar, it is unclear whether the underlying mechanisms are equivalent. We addressed this question by (a) recording event-related brain potentials (ERPs), (b) manipulating the lexicality of neutral stimuli, and (c) giving posthypnotic suggestions (PHS) that written words would lose their meaning. The Stroop effect in the vocal version was twice its manual counterpart. PHS strongly reduced both effects by a similar amount, supporting a common semantic locus during reading. Task- and hypnosis-invariant lexicality effects for neutral words ruled out presemantic reading loci. Articulation-artifact corrected ERPs showed task-invariant Stroop effects in N400 amplitudes, supporting similar semantic loci. However, in the vocal task response-locked ERPs indicated a task-specific Stroop effect over left-inferior frontal and parietal scalp sites, suggesting interference during word production. Interestingly, PHS increased the N1 and decreased the N2 components in ERPs, regardless of congruency, indicating enhanced proactive executive control and diminished demands on conflict-monitoring, respectively. Stroop effects in the N400 were reduced by PHS, confirming their semantic locus. In conclusion, vocal and manual Stroop versions seem to share semantic loci of conflict. The bigger vocal Stroop effect may be attributable to additional loci during word production lexicon. Apparently, PHS diminish Stroop effects by enhancing proactive executive control over lexico-semantic conflicts. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Eliminating stroop effects with post-hypnotic instructions: Brain mechanisms inferred from EEG.

The classic Stroop task demonstrates the persistent and automatic effects of the meaning of color words that are very hard to inhibit when the task is to name the word color. Post-hypnotic instructions may enable highly-hypnotizable participants to inhibit the automatic access to word meaning. Here we compared the consequences of hypnosis alone and hypnosis with post-hypnotic instructions on the Stroop effect and its facilitation and inhibition components. Importantly, we studied the mechanisms of the hypnosis effects at the neural level by analyzing EEG frequencies. Highly hypnotizable participants performed the Stroop task in a counterbalanced design following (1) post-hypnotic suggestions that words had lost their meaning, (2) after hypnosis alone, and (3) in a control condition without hypnosis. The overall Stroop effect and both its facilitation and interference components, were not significant after the post-hypnotic suggestion but in both other conditions. Hypnosis alone neither affected the Stroop effect nor - in contrast to some previous reports and claims - overall performance. EEG recorded during the Stroop task showed a significant increase in both frontal theta and frontal beta power when participants were under the impact of post-hypnotic suggestions, in comparison to the two other sessions. Together, these findings indicate that post-hypnotic suggestions - but not hypnosis alone - are powerful tools for eliciting top down processes. Our EEG findings could be interpreted as clue that this is due to the investment of additional cognitive control.