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Prior studies suggest that the cerebellum contributes to the prediction of action sequences as well as the detection of social violations. In this dynamic causal modeling study, we explored the effective connectivity of the cerebellum with the cerebrum in processing social action sequences. A first model aimed to explore functional cerebello-cerebral connectivity when learning trait/stereotype-implying action sequences. We found many significant bidirectional connectivities between mentalizing areas of the cerebellum and the cerebrum including the temporo-parietal junction (TPJ) and medial prefrontal cortex (mPFC). Within the cerebrum, we found significant connectivity between the right TPJ and the mPFC, and between the TPJ bilaterally. A second model aimed to investigate cerebello-cerebral connectivity when conflicting information arises. We found many significant closed loops between the cerebellum and cerebral mentalizing (e.g. dorsal mPFC) and executive control areas (e.g. medial and lateral prefrontal cortices). Additional closed loops were found within the cerebral mentalizing and executive networks. The current results confirm prior research on effective connectivity linking the cerebellum with mentalizing areas in the cerebrum for predicting social sequences, and extend it to cerebral executive areas for social violations. Overall, this study emphasizes the critical role of cerebello-cerebral connectivity in understanding social sequences.

Conventional transcranial direct-current stimulation (tDCS) delivered to the primary motor cortex (M1) has been shown to enhance implicit motor sequence learning (IMSL). Conventional tDCS targets M1 but also the motor association cortices (MAC), making the precise contribution of M1 to IMSL presently unclear. We aimed to address the roles of these areas by comparing conventional tDCS of M1 and MAC to High-Definition (HD) tDCS, which more focally targets M1. In this sham-controlled, crossover study in 89 healthy adults, we used mixed-effects models to analyze sequence-specific and general learning effects in the acquisition, short- and long-term consolidation phases of IMSL, as measured by the serial reaction time task. Conventional tDCS did not influence general learning, improved sequence-specific learning during acquisition (anodal: M=42.64 ms, sham: M=32.87 ms, p=.041) and deteriorated it at long-term consolidation (anodal: M=75.37 ms, sham: M=86.63 ms, p=.019). HD tDCS did not influence general learning, slowed performance specifically in sequential blocks across all learning phases (all p’s

Humans read the minds of others to predict their actions and efficiently navigate social environments, a capacity called mentalizing. Accumulating evidence suggests that the cerebellum, especially Crus 1 and 2, and lobule IX are involved in identifying the sequence of others’ actions. In the current study, we investigated the neural correlates that underly predicting others’ intentions and how this plays out in the sequence of their actions. We developed a novel intention prediction task, which required participants to put protagonists’ behaviors in the correct chronological order based on the protagonists’ honest or deceitful intentions (i.e., inducing true or false beliefs in others). We found robust activation of cerebellar lobule IX and key mentalizing areas in the neocortex when participants ordered protagonists’ intentional behaviors compared with not ordering behaviors or to ordering object scenarios. Unlike a previous task that involved prediction based on personality traits that recruited cerebellar Crus 1 and 2, and lobule IX (Haihambo et al., 2021), the present task recruited only the cerebellar lobule IX. These results suggest that cerebellar lobule IX may be generally involved in social action sequence prediction, and that different areas of the cerebellum are specialized for distinct mentalizing functions.

Research on the involvement of the cerebellum in social behavior and its relationship with social mentalizing has just begun. Social mentalizing is the ability to attribute mental states such as desires, intentions, and beliefs to others. This ability involves the use of social action sequences which are believed to be stored in the cerebellum. In order to better understand the neurobiology of social mentalizing, we applied cerebellar transcranial direct cur-rent stimulation (tDCS) on 23 healthy participants in the MRI scanner, immediately followed by measuring their brain activity during a task that required to generate the correct sequence of social actions involving false (i.e., outdated) and true beliefs, social routines and non-social (control) events. The results revealed that stimulation decreased task performance along with decreased brain activation in mentalizing areas, including the temporo-parietal junction and the precuneus. This decrease was strongest for true belief sequences compared to the other sequences. These findings support the functional impact of the cerebellum on the mentalizing network and belief mentalizing, contributing to the understanding of the role of the cerebellum in social sequences.

Achtergrond: De huidige behandelingen voor stoornissen in het gebruik van middelen gaan vaak samen met uitval en/of terugval. Transcraniële gelijkstroomstimulatie (tDCS) heeft mogelijk een positief effect op deze problematiek. Doel: Gezien de vele recent verschenen studies, bieden we met deze systematische review een actueel kwalitatief overzicht van studies naar de klinische effecten van tDCS bij personen met een stoornis in het gebruik van middelen. Methode: Uitgebreid literatuuronderzoek in de elektronische database PubMed. We includeerden 43 studies bovenop de 7 die waren opgenomen in de eerdere review van Herremans en Baeken (2017) in dit tijdschrift. Resultaten: De meerderheid van de studies toonde een positief effect aan van tDCS op klinische maten zoals zucht en terugval in middelengebruik. Daarbij was er echter weinig eenvormigheid in de gebruikte protocollen en een grote diversiteit in uitkomstmaten. Conclusie: tDCS kan een effectieve behandeling zijn voor personen met een stoornis in het gebruik van middelen. Optimale parameters dienen vastgesteld te worden om de behandeling maximaal effectief en afgestemd op de individuele patiënt te maken.

Recent advances in social neuroscience have highlighted the critical role of the cerebellum and especially the posterior cerebellar Crus in social mentalizing (i.e., theory of mind). Research in the past 5 years has provided growing evidence supporting the view that the posterior cerebellum builds internal action models of our social interactions to predict how other people's actions will be executed, and what our most likely responses to these actions will be. This paper presents an overview of a series of fMRI experiments on novel tasks involving a combination of (a) the learning or generation of chronological sequences of social actions either in an explicit or implicit manner, which (b) require social mentalizing on another person's mental state such as goals, beliefs, and implied traits. Together, the results strongly confirm the central role of the posterior cerebellar Crus in identifying and automatizing action sequencing during social mentalizing, and in predicting future action sequences based on social mentalizing inferences about others. This research program has important implications: It provides for the first time (a) fruitful starting points for diagnosing and investigating social sequencing dysfunctions in a variety of mental disorders which have also been related to cerebellar dysfunctions, (b) provides the necessary tools for testing whether non-invasive neurostimulation targeting the posterior cerebellum has a causal effect on social functioning, and (c) whether these stimulation techniques and training programs guided by novel cerebellar social sequencing insights, can be exploited to increase posterior cerebellar plasticity in order to alleviate social impairments in mental disorders.

Recent research has indicated that the posterior cerebellum plays a crucial role in social cognition by encoding sequences of social actions. This study investigates its role in learning sequences of stereotype-implying actions by group members. We presented a set of five sentences that each described a group member who performed either stereotype-consistent or inconsistent actions. Participants were instructed to memorize the temporal order of the sentences and infer a common stereotype of the group. As a comparison, we included control conditions where participants had to memorize sequences of nonsocial consistent events or simply read stereotype-consistent sentences without memorizing their order. The results showed that the posterior cerebellum was strongly activated when participants were memorizing the order of the social actions, as opposed to simply reading these social actions. More importantly, when the social actions were inconsistent as opposed to consistent with the stereotype of the group, the posterior cerebellum was activated more strongly. This activation occurred together with cortical recruitment of the mentalizing network involving the dorsomedial prefrontal cortex (dmPFC) during social actions, and additionally the conflict monitoring network involving the lateral prefrontal cortex (PFC) and posterior medial frontal cortex (pmFC) during stereotype-inconsistent actions. These findings suggest that the cerebellum supports not only learning of low-level action sequences, but also of their high-level social implications.

Implicit motor sequence learning (IMSL) is a cognitive function that is known to be directly associated with impaired motor function in Parkinson's disease (PD). Research on healthy young participants shows the potential for transcranial direct current stimulation (tDCS), a noninvasive brain stimulation technique, over the primary motor cortex (M1) to enhance IMSL. tDCS has direct effects on the underlying cortex, but also induces distant (basal ganglia) network effects-hence its potential value in PD, a prime model of basal ganglia dysfunction. To date, only null effects have been reported in persons with PD. However, these studies did not determine the reacquisition effects, although previous studies in healthy young adults suggest that tDCS specifically exerts its beneficial effects on IMSL on reacquisition rather than acquisition. In the current study, we will therefore establish possible reacquisition effects, which are of a particular interest, as long-term effects are vital for the successful functional rehabilitation of persons with PD. Using a sham-controlled, counterbalanced design, we will investigate the potential of tDCS delivered over M1 to enhance IMSL, as measured by the serial reaction time task, in persons with PD and a neurologically healthy age- and sex-matched control (HC) group. Multilevel Mixed Models will be implemented to analyze the sequence-specific aspect of IMSL (primary outcome) and general learning (secondary outcome). We will determine not only the immediate effects that may occur concurrently with the application of tDCS but also the short-term (5 min post-tDCS) and long-term (1 week post-tDCS) reacquisition effects.

Accumulating evidence shows that the posterior cerebellum is involved in mentalizing inferences of social events by detecting sequence information in these events, and building and updating internal models of these sequences. By applying anodal and sham cerebellar transcranial direct current stimulation (tDCS) on the posteromedial cere-bellum of healthy participants, and using a serial reaction time (SRT) task paradigm, the current study examined the causal involvement of the cerebellum in implicitly learning sequences of social beliefs of others (Belief SRT) and non-social colored shapes (Cognitive SRT). Apart from the social or cognitive domain differences, both tasks were structurally identical. Results of anodal stimulation (i.e., 2 mA for 20 min) during the social Belief SRT task, did not show significant improvement in reaction times, however it did reveal generally faster responses for the Cognitive SRT task. This improved performance could also be observed after the cessation of stimulation after 30 min, and up to one week later. Our findings suggest a general positive effect of anodal cerebellar tDCS on implicit non-social Cognitive sequence learning, supporting a causal role of the cerebellum in this learning pro-cess. We speculate that the lack of tDCS modulation of the social Belief SRT task is due to the familiar and over -learned nature of attributing social beliefs, suggesting that easy and automatized tasks leave little room for improvement through tDCS.

Recent research has suggested that the posterior cerebellum encodes predictions and sequences of social actions, and also supports detecting inconsistent trait-implying actions of individuals as discussed by Pu et al. (2020, 2021). However, little is known about the role of the posterior cerebellum in detecting sequencing and inconsistencies by a group of individuals during social interaction. Therefore, the present study investigates these cerebellar functions during inconsistent trait-implying actions in a cooperative context. We presented scenarios in which two fictitious protagonists work together to accomplish a common (positive or negative) goal, followed by six sentences describing actions that implied a personality trait of the protagonists. Participants had to memorize the sequence of these actions. Crucially, the implied trait of the actions of the first protagonist contributed to achieving the goal, whereas the implied trait of the second protagonist was either consistent or inconsistent with that goal. As comparison, we added control conditions where participants had to memorize sequences of nonsocial events (implying the same characteristic of two objects), or simply read the social actions without memorizing their order. We found that the posterior cerebellum was activated while memorizing the sequence of social actions compared to simply reading these actions. More importantly, the cerebellar Crus was more strongly activated when detecting inconsistent (as opposed to consistent) actions, especially when inconsistent negative actions impeded a positive goal, relative to consistent negative actions that supported a negative goal. In conclusion, these findings confirm the crucial role of the posterior cerebellum in memorizing social action sequences and extend the cerebellar function in identifying inconsistencies in an individual's actions in a social collaborative context.

This review focuses on autistic adults and serves 4 purposes: (1) providing an overview of their difficulties regarding mentalizing (understanding others' mental states) and narrative coherence (structured storytelling), (2) highlighting the relations between both skills by examining behavioral observations and shared neural substrates, (3) providing an integrated perspective regarding novel diagnostic tools and support services, and (4) raising awareness of adult autism. We suggest that mentalizing and narrative coherence are related at the behavioral level and neural level. In addition to the traditional mentalizing network, the cerebellum probably serves as an important hub in shared cerebral networks implicated in mentalizing and narrative coherence. Future autism research and support services should tackle new questions within a framework of social cerebellar (dys)functioning.

To study social sequence learning, earlier functional magnetic resonance imaging (fMRI) studies investigated the neural correlates of a novel Belief Serial Reaction Time task in which participants learned sequences of beliefs held by protagonists. The results demonstrated the involvement of the mentalizing network in the posterior cerebellum and cerebral areas (e.g. temporoparietal junction, precuneus and temporal pole) during implicit and explicit social sequence learning. However, little is known about the neural functional interaction between these areas during this task. Dynamic causal modeling analyses for both implicit and explicit belief sequence learning revealed that the posterior cerebellar Crus I & II were effectively connected to cerebral mentalizing areas, especially the bilateral temporoparietal junction, via closed loops (i.e. bidirectional functional connections that initiate and terminate at the same cerebellar and cerebral areas). There were more closed loops during implicit than explicit learning, which may indicate that the posterior cerebellum may be more involved in implicitly learning sequential social information. Our analysis supports the general view that the posterior cerebellum receives incoming signals from critical mentalizing areas in the cerebrum to identify sequences of social actions and then sends signals back to the same cortical mentalizing areas to better prepare for others’ social actions and one’s responses to it.

This study tests the hypothesis that the posterior cerebellum is involved in social cognition by identifying and automatizing sequences of social actions. We applied a belief serial reaction time task (Belief SRT task), which requires mentalizing about two protagonists' beliefs about how many flowers they receive. The protagonists' beliefs could either be true or false depending on their orientation (true belief: oriented towards and directly observing the flowers; or false belief: oriented away and knowing only prior information about flowers). A Control SRT task was created by replacing protagonists and their beliefs with shapes and colors. Participants were explicitly told that there was a standard sequence related to the two protagonists' belief orientations (Belief SRT task) or the shapes' colors (Control SRT task). Both tasks included a Training phase where the standard sequence was repeated and a Test phase where this standard sequence was interrupted by random sequences. As hypothesized, compared with the Control SRT task, the Belief SRT task recruited the posterior cerebellar Crus II and the temporoparietal junction (TPJ) more. Faster response times were correlated with less Crus II activation and with more TPJ activation, suggesting that the Crus II supported automatizing the belief sequence while the TPJ supported inferring the protagonists' beliefs. Also as hypothesized, compared with an implicit version of the Belief SRT task (i.e., participants did not know about the existence of sequences; Ma, Pu, et al., 2021b), the cerebellar Crus I &II was engaged less during initial training and automatic application of the sequence, and the cortical TPJ was activated more in processing random sequences.

Recent studies have documented the involvement of the posterior cerebellar Crus (I & II) in social mentalizing, when sequences play a critical role. We investigated for the first time implicit learning of belief sequences. We created a novel task in which true and false beliefs of other persons were alternated in an adapted serial reaction time (SRT) paradigm (Belief SRT task). Participants observed two protagonists whose beliefs concerning reality were manipulated, depending on their orientation toward the scene (true belief: directly observing the situation) or away from it (false belief: knowing only the prior situation). Unbeknownst to the participants, a fixed sequence related to the two protagonists' belief orientations was repeated throughout the task (Training phase); and to test the acquisition of this fixed sequence, it was occasionally interrupted by random sequences (Test phase). As a nonsocial control, the two protagonists and their orientations were replaced by two different shapes of different colors respectively (Control SRT task). As predicted, the posterior cerebellar Crus I & II were activated during the Belief SRT task and not in the Control SRT task. The Belief SRT task revealed that Crus I was activated during the initial learning of the fixed sequence (Training phase) and when this learned sequence was interrupted by random sequences (Test phase). Moreover, Crus II was activated during occasional reappearance of the learned sequence in the context of sequence violations (Test phase). Our results demonstrate the contribution of the posterior cerebellar Crus during implicit learning and predicting new belief sequences.

Implicit motor sequence learning (IMSL) is affected in Parkinson's disease (PD). Research in healthy young participants shows the potential for transcranial direct-current stimulation (tDCS) over the primary motor cortex (M1) to enhance IMSL. In PD, only null effects have been reported to date. We determined concurrent, short-term, and long-term effects of anodal tDCS over M1 on IMSL, as measured by the serial reaction time (SRT) task, in persons with PD with mild cognitive impairment (MCI). Concurrent (anodal/sham tDCS intervention during the SRT task), short-term (5 min post-intervention), and long-term (1 week post-intervention) effects on IMSL were evaluated in persons with idiopathic PD (Hoehn and Yahr stage II-III) with MCI. Results of 11 persons with PD (8 men and 3 women; mean age = 77.1 years; mean disease duration = 7.7 years) showed significant IMSL in the anodal (p = .016), but not in the sham tDCS condition (p = .937). Post-hoc analyses showed that IMSL reached statistical significance at 1 week post-intervention (p < .001). Anodal tDCS over M1 exerted beneficial effects on IMSL in persons with PD with MCI, in particular one week post-intervention. Our study is the first to report a positive effect of tDCS on IMSL in PD. Further research should include a larger, more cognitively diverse sample and additional follow-up periods.

The posterior cerebellum is responsible for the understanding and learning of sequences of actions by others, which are a prerequisite for social understanding. This study investigates this cerebellar function while navigating towards a goal in a social context. Participants undertook a novel social navigation task requiring them to memorize and subsequently reproduce a protagonist's trajectory through a grid towards a desirable goal. As a non-social control condition, a ball underwent the same trajectory by passively rolling through the grid toward the same endpoint. To establish that memorizing and reproducing a trajectory is a critical cerebellar function, two non-sequencing control conditions were created, which involved the observation only of the trajectory by the protagonist or ball. Our results showed that the posterior cerebellar Crus II was involved in memorizing both social and non-social trajectories, along with the parahippocampal gyrus and other cortical areas involved in social cognition. As hypothesized, cerebellar Crus I was more active when memorizing social as opposed to non-social trajectories. Moreover, cerebellar Crus I and II, and lobule VI, were activated when reproducing both social and non-social trajectories. These findings highlight the involvement of the posterior cerebellar Crus in supporting human goal-directed social navigation.

Objective: Various studies investigated implicit sequence learning in Parkinson's disease (PD) by means of the traditional motor Serial Reaction Time (SRT) task and found a general pattern of impaired sequence learning. However, as perceptual and motor sequences of the SRT-task were correlated in previous studies, implicit sequential knowledge acquisition that is tested independently from motor sequences remains to be determined in PD. In this study, we investigated implicit sequence learning independently from motor sequence learning in individuals with PD. To this end, we used a perceptual SRT-task that did not rely upon sequential motor knowledge. Method: We measured response times (RTs) of 19 participants with PD (Hoehn & Yahr II or III; mean age 65) and 18 age-matched healthy controls (HC; mean age 61.5) in a perceptual SRT-task. General learning effects and sequence-specific learning effects were analyzed using repeated measures ANOVAs. Results: A significant decreasing linear trend (p < .001) in RTs was revealed in both the PD and HC groups as the SRT-task progressed, indicating general learning effects. Notably, a significant, strong main effect of sequence-specific learning occurred (p < .001), irrespective of group (p = .436). Sequence-specific learning did not differ significantly between the PD (M = 156.5 ms; SD = 50.7) and HC group (M = 173.0 ms; SD = 104.2). Bayesian analyses confirmed this as evidence of absence of an effect (B₁₀ = 3.543). Conclusions: Our results suggest that, at least in Hoehn & Yahr stages II and III, implicit sequential knowledge acquisition may be preserved in individuals with PD, when tested independently from motor sequence learning. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Recent studies have documented the involvement of the posterior cerebellar Crus (III) in social mentalizing, when sequences play a critical role. We investigated for the first time implicit learning of belief sequences. We created a novel task in which true and false beliefs of other persons were alternated in an adapted serial reaction time (SRT) paradigm (Belief SRT task). Participants observed two protagonists whose beliefs concerning reality were manipulated, depending on their orientation toward the scene (true belief: directly observing the situation) or away from it (false belief: knowing only the prior situation). Unbeknownst to the participants, a fixed sequence related to the two protagonists' belief orientations was repeated throughout the task (Training phase); and to test the acquisition of this fixed sequence, it was occasionally interrupted by random sequences (Test phase). As a nonsocial control, the two protagonists and their orientations were replaced by two different shapes of different colors respectively (Control SRT task). As predicted, the posterior cerebellar Crus III were activated during the Belief SRT task and not in the Control SRT task. The Belief SRT task revealed that Crus I was activated during the initial learning of the fixed sequence (Training phase) and when this learned sequence was interrupted by random sequences (Test phase). Moreover, Crus II was activated during occasional reappearance of the learned sequence in the context of sequence violations (Test phase). Our results demonstrate the contribution of the posterior cerebellar Crus during implicit learning and predicting new belief sequences.

To investigate whether people can implicitly learn regularities in a social context, we developed a new implicit sequence learning task combining elements from classic false belief and serial reaction time tasks. Participants learned that protagonists were offered flowers at four locations. The protagonists' beliefs concerning the flowers were true or false, depending on their orientation, respectively, toward the scene (so that the flowers could be seen) or away from it. Unbeknown to the participants, there was a fixed belief-related sequence involving three dimensions (identity of the two protagonists, true-false belief orientation held by the protagonists, and flower location as believed by the protagonists). Participants had to indicate as fast as possible where the flowers were located (Experiment 1), or how many flowers were given (Experiment 2) according to the protagonists. Experiment 1 combined perceptual and motor processes (as both the belief-related sequence and motor responses referred to location), whereas Experiment 2 unconfounded the sequence and motor responses, allowing to investigate pure perceptual implicit learning. For reasons of comparison, two non-social conditions were created in Experiment 2 by replacing the protagonists with two non-social objects—colored cameras or shapes. Results revealed significant implicit sequence learning of all belief-related dimensions in Experiment 1, and of true-false belief orientation in Experiment 2, even without a motor confound. Importantly, there were faster reaction times and stronger sequence learning effects in the social than in the non-social conditions. The present findings demonstrate for the first time that people are able to implicitly learn belief-related sequences.

Can we predict the future by reading others’ minds? This study explores whether attributing others’ personality traits facilitates predictions about their future actions and the temporal order of these future actions. Prior evidence demonstrated that the posterior cerebellar crus is involved in identifying the temporal sequence of social actions and the person’s traits they imply. Based on this, we hypothesized that this area might also be recruited in the reverse process; that is, knowledge of another person’s personality traits supports predictions of temporal sequences of others’ actions. In this study, participants were informed about the trait of a person and then had to select actions that were consistent with this information and arrange them in the most likely temporal order. As hypothesized, the posterior cerebellar crus 1 and crus 2 were strongly activated when compared to a control task which involved only the selection of actions (without temporal ordering) or which depicted non-social objects and their characteristics. Our findings highlight the important function of the posterior cerebellar crus in the prediction of social action sequences in social understanding.

An ALE meta-analysis focused on the serial reaction time task published in NeuroImage (Janacsek et al., 2019) demonstrated consistent activation of the basal ganglia across neuroimaging studies featuring sequence ​> ​random block contrasts and no consistent cerebellar activation. To enable valid conclusions regarding the role of the cerebellum in this context, some of the included studies should be excluded (e.g., because the cerebellum was explicitly not scanned). After omitting 6 of 16 studies/subject groups, 70% of the remaining studies did report cerebellar activation. While an ALE analysis of the remaining contrasts confirmed the original results, it may lack the power to detect cerebellar effects. We argue the conclusion that the cerebellum is not involved in sequence-specific learning should be treated with caution.

We investigated the implicit preference in terms of food portion in obesity using the affective priming paradigm. Primes representing different portions of fast food (small, medium and large) were used to assess participants' readiness to respond to a positive or negative target word. A self-reported affective rating scale of food portion and a portion judgment task were administered to determine the explicit preference for food portion and portion misperception, respectively. The results of the affective priming paradigm showed an implicit preference for large food portions in the obese group. No implicit preference in terms of food portion was found in the non-obese group. The explicit preference measure of food portion demonstrated a rather negative attitude for large portions in the obese group, whereas the non-obese group reported no explicit preference in terms of food portion. Thus, unlike the non-obese group, the obese group showed clear discrepancies between implicit and explicit preferences in terms of food portion: obese participants demonstrated an implicit, but not an explicit preference for large food portions. These results could not be attributed to a misperception of food portion, as revealed by the portion judgment task. The current findings suggest that social desirability might conceal self-reported preference in terms of food portion and/or that obese individuals are less aware of their internal preferences.

We investigated an attention bias (AB) for emotional faces in emotional eating (EM). A group obtaining a low score (n = 18) on the Emotional eating scale of the Dutch Eating Behavior Questionnaire and a high scoring group (n = 23) completed the Exogenous Cueing Task (ECT). The ECT experiment measured their reaction times to the location of a target dot preceded by a happy, sad, angry or neutral face cue. The Coping Inventory for Stressful Situations was administrated to collect information on participants’ coping strategies. Compared to the group with a low degree of EM, the high EM group showed significant attentional avoidance of emotional faces, particularly negative faces, in the ECT. The coping questionnaire indicated that the high EM group displayed higher levels of avoidance coping compared to the low EM group. General levels of EM and avoidance coping were also positively correlated, and avoidance coping significantly predicted the level of EM. The findings of the present study indicate that attentional avoidance of emotional content, which has previously been observed in clinical studies of eating disorders ( Cardi et al., 2015a ; Davies et al., 2011 ), is also present in subclinical samples of EM.

We examined the role of sequence awareness in a pure perceptual sequence learning design. Participants had to react to the target's colour that changed according to a perceptual sequence. By varying the mapping of the target's colour onto the response keys, motor responses changed randomly. The effect of sequence awareness on perceptual sequence learning was determined by manipulating the learning instructions (explicit versus implicit) and assessing the amount of sequence awareness after the experiment. In the explicit instruction condition (n = 15), participants were instructed to intentionally search for the colour sequence, whereas in the implicit instruction condition (n = 15), they were left uninformed about the sequenced nature of the task. Sequence awareness after the sequence learning task was tested by means of a questionnaire and the process-dissociation-procedure. The results showed that the instruction manipulation had no effect on the amount of perceptual sequence learning. Based on their report to have actively applied their sequence knowledge during the experiment, participants were subsequently regrouped in a sequence strategy group (n = 14, of which 4 participants from the implicit instruction condition and 10 participants from the explicit instruction condition) and a no-sequence strategy group (n = 16, of which 11 participants from the implicit instruction condition and 5 participants from the explicit instruction condition). Only participants of the sequence strategy group showed reliable perceptual sequence learning and sequence awareness. These results indicate that perceptual sequence learning depends upon the continuous employment of strategic cognitive control processes on sequence knowledge. Sequence awareness is suggested to be a necessary but not sufficient condition for perceptual learning to take place.

Objectives: Parkinson’s disease (PD) has been associated with impaired motor sequence learning (also known as procedural learning). In the current study, we determined the potential of anodal transcranial direct current stimulation delivered over the primary motor cortex to promote the acquisition of sequential movement in a large sample of patients with idiopathic PD and matched controls. Methods: Thirty-one idiopathic PD patients and 33 healthy controls, matched for age, gender, and education, participated in the study. Both groups received anodal and sham transcranial direct current stimulation delivered over the primary motor cortex during the acquisition of a novel sequence movement in the Serial Reaction Time task. Results: Motor sequence learning proved to be intact in patients relative to controls. Compared to sham stimulation, anodal transcranial direct current stimulation of the primary motor cortex did not significantly improve motor sequence learning in patients, nor controls. Conclusions: Anodal transcranial direct current stimulation delivered over the primary motor cortex did not exert a positive effect on the acquisition of sequential movement in patients with Parkinson’s disease. More research is needed to establish the determinants associated with a positive effect of tDCS on sequential skill in PD, such as medication status, the amount of tDCS stimulation needed, as well as the brain regions that need to be targeted to elicit a beneficial response.

Despite the clinical relevance of worrying, its underlying cognitive mechanisms remain poorly understood. Eysenck postulates that high-worriers’ long term memory is characterized by tightly organized clusters with negatively valenced worry-related information, causing this information to be more readily accessible. Based on this premise, we expect (1) that high-worriers will more easily store negative worry-related information, but (2) that they are also more prone to produce false memories about negatively valenced worry-related information. We tested these hypotheses in a healthy student population using the Deese-Roediger-McDermott (DRM) paradigm. The results of our study indicate that worrying is positively correlated (1) with the correct recognition of negative words, and (2) with the production of false recognitions of negative words. These results were unrelated to themes participants often worry about. As expected, there was no correlation between worrying and (false) recognition of positive or neutral words. In conclusion, these findings indicate that worrying is associated with memory biases for negative information. This supports the existence of negatively valenced clustered long term memory structures. However, no support was found for the idea that clusters are concentrated on specific worry themes high worriers frequently worry about.

In the attentional control theory of anxiety, Eysenck, Derakshan, Santos, and Calvo (2007) propose that worrying depletes cognitive resources, thereby reducing the efficiency of cognitive task performance in anxious participants. However, most of the research supporting this hypothesis does not directly address the contribution of worrying to the association between anxiety and cognitive task performance. In the present study we examined the direct effect of induced worrying on cognitive performance in an undergraduate sample, with participants with a high tendency to worry (N=36) and participants with a low tendency to worry (N=30). We used an n-back task to measure their capacity to actively update the content of working memory. Results indicate that a worry-induction decreases general updating efficiency. This decrease in updating efficiency was most pronounced immediately after the worry-induction and disappeared towards the end of the experiment. There was no difference in updating efficiency between participants with a high and low tendency to worry. We can conclude that a worry-induction impairs the updating capacity of working memory, unrelated to a person’s inherent tendency to worry.

We investigated the automaticity of implicit sequence learning by varying perceptual load in a pure perceptual sequence learning paradigm. Participants responded to the randomly changing identity of a target, while the irrelevant target location was structured. In Experiment 1, the target was presented under low or high perceptual load during training, whereas testing occurred without load. Unexpectedly, no sequence learning was observed. In Experiment 2, perceptual load was introduced during the test phase to determine whether load is required to express perceptual knowledge. Learning itself was unaffected by visuospatial demands, but more learning was expressed under high load test conditions. In Experiment 3, we demonstrated that perceptual load is not required for the acquisition of perceptual sequence knowledge. These findings suggest that perceptual load does not mediate the perceptual sequence learning process itself, supporting the automaticity of implicit learning, but is mandatory for the expression of pure perceptual sequence knowledge.

Smaller Simon effects when stimulus locations are repeated on successive trials rather than alternated have been explained by the attention shift hypothesis, suggesting that shifts of attention result in interfering response codes. We investigated whether the attention shift hypothesis can also explain smaller flanker effects for repeated flankers than for alternated flankers, which occur only with directional information. In 3 peripheral letter identification tasks, target locations were cued by partial or complete flanker stimuli. Experiments 1 and 2 showed that directional flankers elicit shifts of attention. However, Experiment 3 revealed that directional flankers induced inverted cuing effects when reacting to the central target arrow was additionally required. These results are difficult to reconcile with the attention shift hypothesis as an explanation for the congruency reduction with repetitions of directional flankers.

We investigated negative priming (NP) in sequence learning, as demonstrated by Cock, Berry, and Buchner (2002). The NP effect in sequence learning refers to the observation that Serial Reaction Time performance becomes impaired when participants respond to a sequence they were previously ignoring. In Experiment 1, we established a NP effect with a complex second-order conditional sequence structure. Experiment 2 showed that NP occurs even when the irrelevant sequence is not synchronised with the relevant sequence. However, the results of Experiment 3 demonstrated that NP was absent when participants did not concurrently respond to a relevant sequence, while being exposed to the irrelevant sequence. These findings indicate that NP extends over complex forms of sequence learning, but requires concurrent learning of relevant sequences. We suggest that NP and the enhancement of (the expression of) learning of irrelevant sequences by concurrent learning of relevant sequences is guided by attentional processes.

We investigated the contributions of the sequences of effectors and response locations to probabilistic sequence learning in the serial reaction time task by means of bimanual transfer. Participants, trained with the dominant hand, were either required to maintain responding with the dominant hand after transfer or to switch to the nondominant hand. For both groups, half of the participants were transferred to the originally trained sequence, whereas the other half was transferred to a mirror-ordered sequence. This way, the sequence of effectors varied independently of the sequence of response locations. Sequence learning was assessed with probabilistic sequences, composed of either first-order or second-order probabilities. Transfer of sequence knowledge to the nondominant hand was equally good for the originally trained sequence as for the mirrored sequence. This suggests that probabilistic sequence learning can be based on either the sequence of effectors or response locations. However, when participants responded with the dominant hand to a mirrored sequence, transfer performance was disturbed. This indicates that changing both the sequences of effectors and response locations has a disruptive effect on the learning performance.

Background and objectives Learning and memory impairment is one of the most persistent cognitive symptoms in multiple sclerosis (MS). In order to fine-tune rehabilitation interventions, a thorough understanding of the specific involvement of implicit and explicit learning processes underlying this impairment is required. To this aim, we determined sequential motor skill acquired under implicit and explicit instructions in MS. Methods Sequential motor skill was determined using the serial reaction time task. In a randomized controlled trial, we assessed implicit and explicit sequence learning in twenty-nine MS patients and twenty-seven matched controls. The primary outcome measure was the difference in RTs between reversed and repeated sequence blocks, indicating sequence learning. Results Patients displayed less sequence learning than controls. This effect seemed more apparent in the explicit sequence learning condition, relative to the implicit sequence learning condition. Preliminary evidence suggeststhat explicit learning impairment was most obvious in patients with progressive MS. Conclusion Our results indicate that the acquisition of sequential motor skill is markedly impaired in MS patients, notably in patients with progressive MS. Implicit learning processes seem overall better preserved, suggesting that implicit learning strategies should be preferred over explicit learning strategies to train sequential motor skill in MS patients.

This study aims to investigate whether attentional biases typically associated with depression and anxiety already exist on a sub-clinical level. A transdiagnostic characteristic, both affective disorders have in common at a sub-clinical level, is persistent negative thinking (PNT), called rumination in depression and worrying in anxiety disorders. We investigated the association between these two types of PNT and attentional biases, using two different versions of the exogenous cueing tasks (ECT) in two different experiments. In Experiment 1, the cues of the ECT were negative and positive personality traits. This allowed us to investigate whether high-ruminators (N = 29), analogous to depressed patients, have difficulties to disengage attention from negative personality traits, as compared to low-ruminators (N = 40). In Experiment 2, the cues of the ECT were negative words related to themes participants frequently worry about versus positive words. This was done to investigate whether high-worriers (N = 26), analogous to anxious persons, have a strong tendency to automatically direct attention toward worry-related information, as compared to low-worriers (N = 27). The results of Experiment 1 showed that high-ruminators have difficulties to disengage their attention from negative personality traits. The results of Experiment 2 indicated that there were no attentional biases for high-worriers. These results show that the attentional bias typically associated with depression is already present at a sub-clinical level, whereas this seems not to be the case for the attentional bias typically associated with anxiety.

We investigated the effect of a secondary task on implicit sequence learning in children and young adults. A serial reaction time (SRT) task was administered to 8-to-10 year old children and 18-to-22 year old adults. Participants reacted to the location of a target presented in one of four locations on the screen with a spatially corresponding response key. Unknown to participants, the location at which the target appeared was structured according to a deterministic sequence. Occasionally, the black target dot was replaced by a red target dog. To assess the effect of attentional load on implicit sequence learning, half of the participants of each age group was assigned to the single task condition, while the other half executed the task under dual task conditions. Whereas participants in the single task condition could ignore the change in target identity, dual task participants additionally had to count the number of times the black dot was replaced by a red dog to increase the attentional load. Sequence learning was tested under single task conditions in both conditions. Z-transformed results indicate that young adults generally showed more sequence learning than children. Importantly, the secondary task had no effect on sequence learning in children, since children learned as much under dual task conditions as under single task conditions. Adults, on the other hand, showed a different result pattern, as they displayed more sequence learning under single task than under dual task conditions. We surmise that this result is due to the vainly attempt of adults, but not children, to integrate both sequences.

Persistent negative thought is a hallmark feature of both major depressive disorder and generalized anxiety disorder. Despite its clinical significance, little is known about the underlying mechanisms of persistent negative thought. Recent studies suggest that reduced cognitive control might be an explanatory factor. We investigated the association between persistent negative thought and switching between internal representations in working memory, using the internal shift task (IST). The IST was administered to a group of undergraduates, classified as high-ruminators versus low-ruminators, or high-worriers versus low-worriers. Results showed that high-ruminators and high-worriers have more difficulties to switch between internal representations in working memory as opposed to low-ruminators and low-worriers. Importantly, results were only significant when the negative stimuli used in the IST reflected personally relevant worry themes for the participants. The results of this study indicate that rumination and worrying are both associated with reduced cognitive control for verbal information that is personally relevant.

Objective: Freezing of gait (FOG) in Parkinson’s disease (PD) may involve specific impairments in acquiring automaticity under working memory load. This study examined whether implicit sequence learning, with or without a secondary task, is impaired in patients with FOG. Method: Fourteen freezers (FRs), 14 nonfreezers (nFRs), and 14 matched healthy controls (HCs) performed a serial reaction time (SRT) task with a deterministic stimulus sequence under single-task (ST) and dual-task (DT) conditions. The increase in reaction times (RTs) for random compared with sequenced blocks was used as a measure of implicit sequence learning. Neuropsychological tests assessing global cognitive functioning and executive dysfunction were administered in order to investigate their relation to sequence learning. Results: nFRs and HCs showed significant implicit sequence learning effects (p 0.001). FRs demonstrated a tendency to learn sequence-specific information in the SRT-ST task (p 0.07) but not in the SRT-DT task (p 0.69). Severity of FOG, however, correlated positively with SRT-DT task performance (r 0.56; p 0.05). Conclusions: The present results suggest that PD patients suffering from FOG pathology exhibit a specific impairment in the acquisition of automaticity. When working memory capacity is supplementarily loaded by adding a DT, sequence learning in FRs becomes increasingly impaired. These findings indicate that therapies should focus on extensive training in acquiring novel motor activities and reducing working memory load to improve learning in FOG.

Recent studies emphasize a key role of controlled operations, such as set-shifting and inhibition, in the occurrence of freezing of gait (FOG) in Parkinson's disease (PD). However, FOG can also be characterized as a de-automatization disorder, showing impairments in both the execution and acquisition of automaticity. The observed deficits in automaticity and executive functioning indicate that both processes are malfunctioning in freezers. Therefore, to explain FOG from a cognitive-based perspective, we present a model describing the pathways involved in automatic and controlled processes prior to a FOG episode. Crucially, we focus on disturbances in automaticity and control, regulated by the frontostriatal circuitry. In complex situations, non-freezing PD patients may compensate for deficits in automaticity by switching to increased cognitive control. However, as both automatic and controlled processes are more severely impaired in freezers, this hampers cognitive compensation in FOG, resulting in a potential breakdown. Future directions for cognitive rehabilitation are proposed, based on the cognitive model we put forward. ispartof: Frontiers in Human Neuroscience vol:6 issue:DEC pages:1-6 ispartof: location:Switzerland status: published

Freezing of gait (FOG) is a very disabling symptom affecting up to half of the patients with Parkinson's disease (PD). Evidence is accumulating that FOG is caused by a complex interplay between motor, cognitive and affective factors, rather than being a pure motor phenomenon. In the current paper, we review the evidence on the specific role of cognitive factors in FOG. Results from behavioral studies show that patients with FOG experience impairments in executive functioning and response selection which predict that motor learning may be compromised. Brain imaging studies strengthen the neural basis of a potential association between FOG and cognitive impairment, but do not clarify whether it is a primary or secondary determinant of FOG. A FOG-related reduction of cognitive resources implies that adaptation of rehabilitation interventions is indicated for patients with FOG to promote the consolidation of learning.

We investigated the influence of implicit learning on cognitive control. In a sequential Stroop task, participants implicitly learned a sequence placed on the color of the Stroop words. In Experiment 1, Stroop conflict was lower in sequenced than in random trials (learning-improved control). However, as these results were derived from an interaction between learning and conflict, they could also be explained by improved implicit learning (difference between random and sequenced trials), under incongruent as compared to congruent trials (control-improved learning). Therefore, we further unraveled the direction of the interaction in two additional experiments. In Experiment 2, participants who learned the color sequence were no better at resolving conflict than participants who did not undergo sequence training. This shows that implicit knowledge does not directly reduce conflict (no learning-improved control). In Experiment 3, the amount of conflict did not directly improve learning either (no control-improvedlearning). However, conflict had a significant impact on the expression of implicit learning as most knowledge was expressed under the highest amount of conflict. Thus, task-optimization was accomplished by an increased reliance on implicit sequence knowledge under high conflict. These findings demonstrate that implicit learning processes can be flexibly recruited to support cognitive control functions.

We investigated response activation and suppression processes in Parkinson's disease patients with freezing of gait (FOG). Fourteen freezers, 14 nonfreezers and 14 matched healthy controls performed the attention network task (ANT) and the Stroop task. The former task has more stimulus-response overlap and is expected to elicit stronger irrelevant response activation, requiring more inhibition. Congruency effects were used as a general measure of conflict resolution. Supplementary RT distribution analyses were utilized to calculate conditional accuracy functions (CAFs) and delta plots to measure response activation and suppression processes. In agreement with previous research, freezers showed a general conflict resolution deficit compared to nonfreezers and healthy controls. Moreover, CAFs pointed to a strong initial incorrect response activation in FOG. As expected, conflict resolution impairment was only apparent in the ANT, and not in the Stroop task. These results suggest an imbalance between automatic and controlled processes in FOG, leading to a breakdown in both motor and cognitive response control.