Search

While the analysis of gait and balance can be an important indicator of age- or disease-related changes, it remains unclear if repeated performance of gait and balance tests in healthy adults leads to habituation effects, if short-term gait and balance training can improve gait and balance performance, and whether the placement of wearable sensors influences the measurement accuracy. Healthy adults were assessed before and after performing weekly gait and balance tests over three weeks by using a force plate, motion capturing system and smartphone. The intervention group (n = 25) additionally received a home-based gait and balance training plan. Another sample of healthy adults (n = 32) was assessed once to analyze the impact of sensor placement (lower back vs. lower abdomen) on gait and balance analysis. Both the control and intervention group exhibited improvements in gait/stance. However, the trends over time were similar for both groups, suggesting that targeted training and repeated task performance equally contributed to the improvement of the measured variables. Since no significant differences were found in sensor placement, we suggest that a smartphone used as a wearable sensor could be worn both on the lower abdomen and the lower back in gait and balance analyses.

This review aimed to systematically identify and comprehensively review the role of the cerebellum in performance monitoring, focusing on learning from and on processing of external feedback in non-motor learning. While 1078 articles were screened for eligibility, ultimately 36 studies were included in which external feedback was delivered in cognitive tasks and which referenced the cerebellum. These included studies in patient populations with cerebellar damage and studies in healthy subjects applying neuroimaging. Learning performance in patients with different cerebellar diseases was heterogeneous, with only about half of all patients showing alterations. One patient study using EEG demonstrated that damage to the cerebellum was associated with altered neural processing of external feedback. Studies assessing brain activity with task-based fMRI or PET and one resting-state functional imaging study that investigated connectivity changes following feedback-based learning in healthy participants revealed involvement particularly of lateral and posterior cerebellar regions in processing of and learning from external feedback. Cerebellar involvement was found at different stages, e.g., during feedback anticipation and following the onset of the feedback stimuli, substantiating the cerebellum's relevance for different aspects of performance monitoring such as feedback prediction. Future research will need to further elucidate precisely how, where, and when the cerebellum modulates the prediction and processing of external feedback information, which cerebellar subregions are particularly relevant, and to what extent cerebellar diseases alter these processes., (© 2024. The Author(s).)

Recent research has highlighted cerebellar involvement in cognition and several psychiatric conditions such as mood and anxiety disorders and schizophrenia. Attention-deficit/hyperactivity disorder and autism spectrum disorder have been linked to reduced cerebellar volume as well. Cerebellar alterations are frequently present after early adversity in humans and animals, but a systematic integration of results is lacking. To this end, a systematic literature search was conducted in PubMed, Web of Science, and EBSCO databases using the keywords "early adversity OR early life stress" AND "cerebellum OR cerebellar." A total of 45 publications met the inclusion criteria: 25 studies investigated human subjects and 20 reported results from animal models. Findings in healthy subjects show bilateral volume reduction and decreased functional connectivity within the cerebellum and between the cerebellum and frontal regions after adversity throughout life, especially when adversity was assessed with the Childhood Trauma Questionnaire. In clinical populations, adults demonstrate increased cerebellar volume and functional connectivity after adversity, whereas pediatric patients show reduced cerebellar volume. Animal findings reveal cerebellar alterations without necessarily co-occurring pathological behavior, highlighting alterations in stress hormone receptor levels, cell density, and neuroinflammation markers. Cerebellar alterations after early adversity are robust findings across human and animal studies and occur independent of clinical symptoms., (© 2024 The Author(s). Developmental Psychobiology published by Wiley Periodicals LLC.)

While most people are right-handed, a minority are left-handed or mixed-handed. It has been suggested that mental and developmental disorders are associated with increased prevalence of left-handedness and mixed-handedness. However, substantial heterogeneity exists across disorders, indicating that not all disorders are associated with a considerable shift away from right-handedness. Increased frequencies in left- and mixed-handedness have also been associated with more severe clinical symptoms, indicating that symptom severity rather than diagnosis explains the high prevalence of non-right-handedness in mental disorders. To address this issue, the present study investigated the association between handedness and measures of stress reactivity, depression, mania, anxiety, and positive and negative symptoms in a large sample of 994 healthy controls and 1213 patients with DSM IV affective disorders, schizoaffective disorders, or schizophrenia. A series of complementary analyses revealed lower lateralization and a higher percentage of mixed-handedness in patients with major depression (14.9%) and schizophrenia (24.0%) compared to healthy controls (12%). For patients with schizophrenia, higher symptom severity was associated with an increasing tendency towards left-handedness. No associations were found for patients diagnosed with major depression, bipolar disorder, or schizoaffective disorder. In healthy controls, no association between hand preference and symptoms was evident. Taken together, these findings suggest that both diagnosis and symptom severity are relevant for the shift away from right-handedness in mental disorders like schizophrenia and major depression., (© 2024. The Author(s).)

It is easier to execute a response in the promise of a reward and withhold a response in the promise of a punishment than vice versa, due to a conflict between cue-related Pavlovian and outcome-related instrumental action tendencies in the reverse conditions. This robust learning asymmetry in go and nogo learning is referred to as the Pavlovian bias. Interestingly, it is similar to motivational tendencies reported for affective facial expressions, i.e., facilitation of approach to a smile and withdrawal from a frown. The present study investigated whether and how learning from emotional faces instead of abstract stimuli modulates the Pavlovian bias in reinforcement learning. To this end, 137 healthy adult participants performed an orthogonalized Go/Nogo task that fully decoupled action (go/nogo) and outcome valence (win points/avoid losing points). Three groups of participants were tested with either emotional facial cues whose affective valence was either congruent (CON) or incongruent (INC) to the required instrumental response, or with neutral facial cues (NEU). Relative to NEU, the Pavlovian bias was reduced in both CON and INC, though still present under all learning conditions. Importantly, only for CON, the reduction of the Pavlovian bias effect was adaptive by improving learning performance in one of the conflict conditions. In contrast, the reduction of the Pavlovian bias in INC was completely driven by decreased learning performance in non-conflict conditions. These results suggest a potential role of arousal/salience in Pavlovian-instrumental regulation and cue-action congruency in the adaptability of goal-directed behavior. Implications for clinical application are discussed., (© 2024. The Author(s).)

Background: Alcohol use disorder (AUD) affects 283 million people worldwide and its prevalence is increasing. Despite the role of the cerebellum in executive control and its sensitivity to alcohol, few studies have assessed its involvement in AUD-relevant functional networks. The goal of this study is to compare resting-state functional connectivity (FC) patterns in abstinent adults with a history of AUD and controls (CTL). We hypothesized that group differences in cerebro-cerebellar FC would be present, particularly within the frontoparietal/executive control network (FPN)., Methods: Twenty-eight participants completed a resting-state functional magnetic resonance imaging (rsfMRI) study. CTL participants had no history of AUD, comorbid psychological conditions, or recent heavy drinking and/or drug use. AUD participants had a history of AUD, with sobriety for at least 30 days prior to data collection. Multivariate pattern analysis, an agnostic, whole-brain approach, was used to identify regions with significant differences in FC between groups. Seed-based analyses were then conducted to determine the directionality and extent of these FC differences. Associations between FC strength and executive function were assessed using correlations with Wisconsin Card Sorting Test (WCST) performance., Results: There were significant group differences in FC in nodes of the FPN, ventral attention network, and default mode network. Post hoc analyses predominantly identified FC differences within the cerebro-cerebellar FPN, with AUD showing significantly less FC within the FPN. In AUD, FC strength between FPN clusters identified in the multivariate pattern analysis (MVPA) analysis (Left Crus II, Right Frontal Cortex) was positively associated with performance on the WCST., Conclusions: Our results show less engagement of the FPN in individuals with AUD than in CTL. FC strength within this network was positively associated with performance on the WCST. These findings suggest that long-term heavy drinking alters cerebro-cerebellar FC, particularly within networks that are involved in executive function., (© 2023 Research Society on Alcohol.)

Recent studies increasingly highlight involvement of the cerebellum in drug craving and addiction. However, its exact role, that is, whether the cerebellum is a critical component of a brain network underlying addictive behaviour, or whether it rather is a facilitator or mediator, is still unclear. Findings concerning the newly recognized internet gaming disorder (IGD) suggest that changes in cerebellar connectivity and functioning are associated with behavioural/non-substance addiction. Here, we systematically review the literature on IGD and cerebellar involvement following the PRISMA guidelines. A total of 13 neuroimaging studies met the inclusion criteria. Studies utilized a broad range of diagnostic instruments and resulting cut-off criteria, rendering it difficult to compare findings. Results on altered cerebro-cerebellar connectivity in patients with IGD are mixed; most studies report altered or increased functional connectivity. Moreover, decreased cerebellar grey matter volume is reported. Studies have further indicated that differential activation patterns in the cerebellum may enable discrimination between healthy subjects and subjects with IGD, even allowing for prediction of treatment outcomes. Given the strong connectivity between the cerebellum and cerebral regions, the cerebellum may act as an intermediary between regions involved in craving and addiction and consequently affect symptoms of IGD. Results suggest differential involvement of the cerebellar lobes, emphasizing a need for high-resolution parcellation of the cerebellum in future studies. However, the studies included in the present review have small sample sizes and include mostly male participants. Thus, results may have limited generalizability yet highlight a crucial role of the cerebellum in IGD that needs further investigation., (© 2023 The Authors. Addiction Biology published by John Wiley & Sons Ltd on behalf of Society for the Study of Addiction.)

Exposure to adversities in early life appears to affect the development of white matter, especially oligodendrocytes. Furthermore, altered myelination is present in regions subjected to maturation during the developmental time when early adversities are experienced. In this review, studies applying two well-established animal models of early life adversity, namely maternal separation and maternal immune activation, focusing on oligodendrocyte alterations and resulting implications for psychiatric disorders are discussed. Studies revealed that myelination is reduced as a result of altered oligodendrocyte expression. Furthermore, early adversity is associated with increased cell death, a simpler morphology, and inhibited oligodendrocyte maturation. However, these effects seem to be region- specific as some brain regions show increased expression while others show decreased expression of oligodendroglia-related genes, and they occur especially in regions of ongoing development. Some studies furthermore suggest that early adversity leads to premature differentiation of oligodendrocytes. Importantly, especially early exposure results in stronger oligodendrocyte-related impairments. However, resulting alterations are not restricted to exposure during the early pre- and postnatal days as social isolation after weaning leads to fewer internodes and branches and shorter processes of oligodendrocytes in adulthood. Eventually, the found alterations may lead to dysfunction and long-lasting alterations in structural brain development associated with psychiatric disorders. To date, only few preclinical studies have focused on the effects of early adversity on oligodendrocytes. More studies including several developmental stages are needed to further disentangle the role of oligodendrocytes in the development of psychiatric disorders., (© 2023. The Author(s).)

Most studies on emotion processing induce emotions through images or films. However, this method lacks ecological validity, limiting generalization to real-life emotion processing. More realistic paradigms using virtual reality (VR) may be better suited to investigate authentic emotional states and their neuronal correlates. This pre-registered study examines the neuronal underpinnings of naturalistic fear, measured using mobile electroencephalography (EEG). Seventy-five healthy participants walked across a virtual plank which extended from the side of a skyscraper-either 80 storeys up (the negative condition) or at street level (the neutral condition). Subjective ratings showed that the negative condition induced feelings of fear. Following the VR experience, participants passively viewed negative and neutral images from the international affective picture system (IAPS) outside of VR. We compared frontal alpha asymmetry between the plank and IAPS task and across valence of the conditions. Asymmetry indices in the plank task revealed greater right-hemispheric lateralization during the negative VR condition, relative to the neutral VR condition and to IAPS viewing. Within the IAPS task, no significant asymmetries were detected. In summary, our findings indicate that immersive technologies such as VR can advance emotion research by providing more ecologically valid ways to induce emotion., Competing Interests: We declare we have no competing interests., (© 2023 The Authors.)

There is limited convergence in neuroimaging investigations into volumes of subcortical brain regions in social anxiety disorder (SAD). The inconsistent findings may arise from variations in methodological approaches across studies, including sample selection based on age and clinical characteristics. The ENIGMA-Anxiety Working Group initiated a global mega-analysis to determine whether differences in subcortical volumes can be detected in adults and adolescents with SAD relative to healthy controls. Volumetric data from 37 international samples with 1115 SAD patients and 2775 controls were obtained from ENIGMA-standardized protocols for image segmentation and quality assurance. Linear mixed-effects analyses were adjusted for comparisons across seven subcortical regions in each hemisphere using family-wise error (FWE)-correction. Mixed-effects d effect sizes were calculated. In the full sample, SAD patients showed smaller bilateral putamen volume than controls (left: d = -0.077, p FWE  = 0.037; right: d = -0.104, p FWE  = 0.001), and a significant interaction between SAD and age was found for the left putamen (r = -0.034, p FWE  = 0.045). Smaller bilateral putamen volumes (left: d = -0.141, p FWE  < 0.001; right: d = -0.158, p FWE  < 0.001) and larger bilateral pallidum volumes (left: d = 0.129, p FWE  = 0.006; right: d = 0.099, p FWE  = 0.046) were detected in adult SAD patients relative to controls, but no volumetric differences were apparent in adolescent SAD patients relative to controls. Comorbid anxiety disorders and age of SAD onset were additional determinants of SAD-related volumetric differences in subcortical regions. To conclude, subtle volumetric alterations in subcortical regions in SAD were detected. Heterogeneity in age and clinical characteristics may partly explain inconsistencies in previous findings. The association between alterations in subcortical volumes and SAD illness progression deserves further investigation, especially from adolescence into adulthood., (© 2023. The Author(s), under exclusive licence to Springer Nature Limited.)

Virtual reality (VR) is increasingly used in neuroscientific research to increase ecological validity without sacrificing experimental control, to provide a richer visual and multisensory experience, and to foster immersion and presence in study participants, which leads to increased motivation and affective experience. But the use of VR, particularly when coupled with neuroimaging or neurostimulation techniques such as electroencephalography (EEG), functional magnetic resonance imaging (fMRI), or transcranial magnetic stimulation (TMS), also yields some challenges. These include intricacies of the technical setup, increased noise in the data due to movement, and a lack of standard protocols for data collection and analysis. This chapter examines current approaches to recording, pre-processing, and analyzing electrophysiological (stationary and mobile EEG), as well as neuroimaging data recorded during VR engagement. It also discusses approaches to synchronizing these data with other data streams. In general, previous research has used a range of different approaches to technical setup and data processing, and detailed reporting of procedures is urgently needed in future studies to ensure comparability and replicability. More support for open-source VR software as well as the development of consensus and best practice papers on issues such as the handling of movement artifacts in mobile EEG-VR will be essential steps in ensuring the continued success of this exciting and powerful technique in neuroscientific research., (© 2023. The Author(s), under exclusive license to Springer Nature Switzerland AG.)

The amygdala is a core structure in the neuronal network underlying emotion processing in the vertebrate brain. Its structure and function have been extensively studied in both neuroimaging studies in human volunteers and comparative studies in animal models. Across different studies and research questions regarding the amygdala, one often-encountered finding is that the left and the right amygdala are not equivalent in terms of function and structure. Hemispheric asymmetries in the amygdala have been reported on many different levels, yet a systematic integration of these findings has been missing from the literature. Researchers in both cognitive and clinical neurosciences are often puzzled why they find a specific effect or association for the left but not the right amygdala, or vice versa. In this review article, we provide an integrated overview of existing basic and clinical findings regarding amygdala asymmetries in structure, connections, and functions. Importantly, the literature suggests that functional amygdala lateralization is determined by temporal characteristics, emotional valence, and perceptual properties. Furthermore, we highlight alterations of amygdala asymmetries reported in different patient groups, thereby allowing for a deeper understanding of atypical amygdala asymmetries. Lastly, we aim to provide guidelines and approaches concerning the interpretation of results for researchers investigating amygdala asymmetries., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

A variety of organisms including mammals have evolved a 24h, self-sustained timekeeping machinery known as the circadian clock (biological clock), which enables to anticipate, respond, and adapt to environmental influences such as the daily light and dark cycles. Proper functioning of the clock plays a pivotal role in the temporal regulation of a wide range of cellular, physiological, and behavioural processes. The disruption of circadian rhythms was found to be associated with the onset and progression of several pathologies including sleep and mental disorders, cancer, and neurodegeneration. Thus, the role of the circadian clock in health and disease, and its clinical applications, have gained increasing attention, but the exact mechanisms underlying temporal regulation require further work and the integration of evidence from different research fields. In this review, we address the current knowledge regarding the functioning of molecular circuits as generators of circadian rhythms and the essential role of circadian synchrony in a healthy organism. In particular, we discuss the role of circadian regulation in the context of behaviour and cognitive functioning, delineating how the loss of this tight interplay is linked to pathological development with a focus on mental disorders and neurodegeneration. We further describe emerging new aspects on the link between the circadian clock and physical exercise-induced cognitive functioning, and its current usage as circadian activator with a positive impact in delaying the progression of certain pathologies including neurodegeneration and brain-related disorders. Finally, we discuss recent epidemiological evidence pointing to an important role of the circadian clock in mental health., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Yalçin, Mundorf, Thiel, Amatriain-Fernández, Kalthoff, Beucke, Budde, Garthus-Niegel, Peterburs and Relógio.)

The term "Pavlovian" bias describes the phenomenon that learning to execute a response to obtain a reward or to inhibit a response to avoid punishment is much easier than learning the reverse. The present study investigated the interplay between this learning bias and individual levels of social anxiety. Since avoidance behavior is a hallmark feature of social anxiety and high levels of social anxiety have been associated with better learning from negative feedback, it is conceivable that the Pavlovian bias is altered in individuals with high social anxiety, with a strong tendency to avoid negative feedback, especially (but not only) in a nogo context. In addition, learning may be modulated by the individual propensity to learn from positive or negative feedback, which can be assessed as a trait-like feature. A sample of 84 healthy university students completed an orthogonalized go/nogo task that decoupled action type (go/nogo) and outcome valence (win/avoid) and a probabilistic selection task based upon which the individual propensity to learn from positive and negative feedback was determined. Self-reported social anxiety and learning propensity were used as predictors in linear mixed-effect model analysis of performance accuracy in the go/nogo task. Results revealed that high socially anxious subjects with a propensity to learn better from negative feedback showed particularly pronounced learning for nogo to avoid while lacking significant learning for nogo to win as well as go to avoid. This result pattern suggests that high levels of social anxiety in concert with negative learning propensity hamper the overcoming of Pavlovian bias in a win context while facilitating response inhibition in an avoidance context. The present data confirm the robust Pavlovian bias in feedback-based learning and add to a growing body of evidence for modulation of feedback learning by individual factors, such as personality traits. Specifically, results show that social anxiety is associated with altered Pavlovian bias, and might suggest that this effect could be driven by altered basal ganglia function primarily affecting the nogo pathway., (© 2021. The Author(s).)

Background: In the general population, 10.6% of people favor their left hand over the right for motor tasks. Previous research suggests higher prevalence of atypical (left-, mixed-, or non-right-) handedness in (i) twins compared to singletons, and in (ii) monozygotic compared to dizygotic twins. Moreover, (iii) studies have shown a higher rate of handedness concordance in monozygotic compared to dizygotic twins, in line with genetic factors playing a role for handedness., Methods: By means of a systematic review, we identified 59 studies from previous literature and performed three sets of random effects meta-analyses on (i) twin-to-singleton Odds Ratios (21 studies, n = 189,422 individuals) and (ii) monozygotic-to-dizygotic twin Odds Ratios (48 studies, n = 63,295 individuals), both times for prevalence of left-, mixed-, and non-right-handedness. For monozygotic and dizygotic twin pairs we compared (iii) handedness concordance Odds Ratios (44 studies, n = 36,217 twin pairs). We also tested for potential effects of moderating variables, such as sex, age, the method used to assess handedness, and the twins' zygosity., Results: We found (i) evidence for higher prevalence of left- (Odds Ratio = 1.40, 95% Confidence Interval = [1.26, 1.57]) and non-right- (Odds Ratio = 1.36, 95% Confidence Interval = [1.22, 1.52]), but not mixed-handedness (Odds Ratio = 1.08, 95% Confidence Interval = [0.52, 2.27]) among twins compared to singletons. We further showed a decrease in Odds Ratios in more recent studies (post-1975: Odds Ratio = 1.30, 95% Confidence Interval = [1.17, 1.45]) compared to earlier studies (pre-1975: Odds Ratio = 1.90, 95% Confidence Interval = [1.59-2.27]). While there was (ii) no difference between monozygotic and dizygotic twins regarding prevalence of left- (Odds Ratio = 0.98, 95% Confidence Interval = [0.89, 1.07]), mixed- (Odds Ratio = 0.96, 95% Confidence Interval = [0.46, 1.99]), or non-right-handedness (Odds Ratio = 1.01, 95% Confidence Interval = [0.91, 1.12]), we found that (iii) handedness concordance was elevated among monozygotic compared to dizygotic twin pairs (Odds Ratio = 1.11, 95% Confidence Interval = [1.06, 1.18]). By means of moderator analyses, we did not find evidence for effects of potentially confounding variables., Conclusion: We provide the largest and most comprehensive meta-analysis on handedness in twins. Although a raw, unadjusted analysis found a higher prevalence of left- and non-right-, but not mixed-handedness among twins compared to singletons, left-handedness was substantially more prevalent in earlier than in more recent studies. The single large, recent study which included birth weight, Apgar score and gestational age as covariates found no twin-singleton difference in handedness rate, but these covariates could not be included in the present meta-analysis. Together, the secular shift and the influence of covariates probably make it unsafe to conclude that twinning has a genuine relationship to handedness., (© 2022. The Author(s).)

Recent large-scale neuroimaging studies suggest that most parts of the human brain show structural differences between the left and the right hemisphere. Such structural hemispheric asymmetries have been reported for both cortical and subcortical structures. Interestingly, many neurodevelopmental and psychiatric disorders have been associated with altered functional hemispheric asymmetries. However, findings concerning the relation between structural hemispheric asymmetries and disorders have largely been inconsistent, both within specific disorders as well as between disorders. In the present review, we compare structural asymmetries from a clinical neuroscience perspective across different disorders. We focus especially on recent large-scale neuroimaging studies, to concentrate on replicable effects. With the notable exception of major depressive disorder, all reviewed disorders were associated with distinct patterns of alterations in structural hemispheric asymmetries. While autism spectrum disorder was associated with altered structural hemispheric asymmetries in a broader range of brain areas, most other disorders were linked to more specific alterations in brain areas related to cognitive functions that have been associated with the symptomology of these disorders. The implications of these findings are highlighted in the context of transdiagnostic approaches to psychopathology., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Mundorf, Peterburs and Ocklenburg.)

Alterations in functional brain lateralization, often indicated by an increased prevalence of left- and/or mixed-handedness, have been demonstrated in several psychiatric and neurodevelopmental disorders like schizophrenia or autism spectrum disorder. For depression, however, this relationship is largely unclear. While a few studies found evidence that handedness and depression are associated, both the effect size and the direction of this association remain elusive. Here, we collected data from 87 studies totaling 35,501 individuals to provide a precise estimate of differences in left-, mixed- and non-right-handedness between depressed and healthy samples and computed odds ratios (ORs) between these groups. Here, an OR > 1 signifies higher rates of atypical handedness in depressed compared to healthy samples. We found no differences in left- (OR = 1.04, 95% CI = [0.95, 1.15], p = .384), mixed- (OR = 1.64, 95% CI = [0.98, 2.74], p = .060) or non-right-handedness (OR = 1.05, 95% CI = [0.96, 1.15], p = .309) between the two groups. We could thus find no link between handedness and depression on the meta-analytical level., (Copyright © 2021. Published by Elsevier B.V.)

The present study investigated whether the representation of subjective preferences in the event-related potential is manipulable through selective devaluation, i.e., the consumption of a specific food item until satiety. Thirty-four participants completed a gambling task in which they chose between virtual doors to find one of three snack items, representing a high, medium, or low preference outcome as defined by individual desire-to-eat ratings. In one of two test sessions, they underwent selective devaluation of the high preference outcome. In the other, they completed the task on an empty stomach. Consistent with previous findings, averaged across sessions, amplitudes were increased for more preferred rewards in the time windows of P2, late FRN, and P300. As hypothesised, we also found a selective devaluation effect for the high preference outcome in the P300 time window, reflected in a decrease in amplitude. The present results provide evidence for modulations of reward processing not only by individual factors, such as subjective preferences, but also by the current motivational state. Importantly, the present data suggest that selective devaluation effects in the P300 may be a promising tool to further characterise altered valuation of food rewards in the context of eating disorders and obesity., (© 2021. The Author(s).)

Perceptual decision making involves choices between alternatives based on sensory information. Studies in primates and rodents revealed a stochastic perceptual evidence accumulation process that, after reaching threshold, results in action execution. Birds represent a cognitively highly successful vertebrate class that has been evolving independent from mammals for more than 300 million years. The present study investigated whether perceptual decision making in pigeons shows behavioral and computational dynamics comparable to those in mammals and rodents. Using a novel "pigeon helmet" with liquid shutter displays that controls visual input to individual eyes/hemispheres with precise timing, we indeed revealed highly similar dynamics of perceptual decision making. Thus, both mammals and birds seem to share this core cognitive process that possibly represents a fundamental constituent of decision making throughout vertebrates. Interestingly, in our experiments we additionally discovered that both avian hemispheres start independent sensory accumulation processes without any major interhemispheric exchange. Because birds lack a corpus callosum and have only a small anterior commissure, they seem to be forced to decide on motor responses based on unihemispheric decisions under conditions of time pressure. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Learning to execute a response to obtain a reward or to inhibit a response to avoid punishment is much easier than learning the reverse, which has been referred to as "Pavlovian" biases. Despite a growing body of research into similarities and differences between active and observational learning, it is as yet unclear if Pavlovian learning biases are specific for active task performance, i.e., learning from feedback provided for one's own actions, or if they persist also when learning by observing another person's actions and subsequent outcomes. The present study, therefore, investigated the influence of action and outcome valence in active and observational feedback learning. Healthy adult volunteers completed a go/nogo task that decoupled outcome valence (win/loss) and action (execution/inhibition) either actively or by observing a virtual co-player's responses and subsequent feedback. Moreover, in a more naturalistic follow-up experiment, pairs of subjects were tested with the same task, with one subject as active learner and the other as observational learner. The results revealed Pavlovian learning biases both in active and in observational learning, with learning of go responses facilitated in the context of reward obtainment, and learning of nogo responses facilitated in the context of loss avoidance. Although the neural correlates of active and observational feedback learning have been shown to differ to some extent, these findings suggest similar mechanisms to underlie both types of learning with respect to the influence of Pavlovian biases. Moreover, performance levels and result patterns were similar in those observational learners who had observed a virtual co-player and those who had completed the task together with an active learner, suggesting that inclusion of a virtual co-player in a computerized task provides an effective manipulation of agency.

Several fMRI studies have shown that the superior cerebellum exhibits load-dependent activations during encoding of letters in a Sternberg verbal working memory (VWM) task. It has been hypothesized that the cerebellum regulates the acquisition of sensory data across all modalities, and thus, that VWM load activations may reflect high- vs low-load differences in sensory acquisition demands. Therefore, increased difficulty in sensory data acquisition should elicit greater activation in the cerebellum. The present fMRI study manipulated sensory acquisition in VWM by presenting visually degraded and non-degraded stimuli with high and low memory loads, thereby identifying load-dependent regions of interest in the cerebellum, and then testing if these regions showed greater activation for degraded stimuli. Results yielded partial support for the sensory acquisition hypothesis in a load-dependent region of the vermis, which showed significantly greater activation for degraded relative to non-degraded stimuli. Because eye movements did not differ for these stimulus types, and degradation-related activations were present after co-varying eye movements, this activation appears to be related to perceptual rather than oculomotor demands. In contrast to the vermis, load-sensitive regions of the cerebellar hemispheres did not show increased activation for degraded stimuli. These findings point to an overall function of association-based prediction that may underlie general cerebellar function, with perceptual prediction of stimuli from partial representations occurring in the vermis, and articulatory prediction occurring in the hemispheres.

Effective response inhibition requires efficient bottom-up perceptual processing and effective top-down inhibitory control. To investigate the role of hemispheric asymmetries in these processes, 49 right- and 50 left-handers completed a tachistoscopic Go/Nogo task with positive and negative emotional faces while ERPs were recorded. Frontal resting state EEG asymmetry was assessed as a marker of individual differences in prefrontal inhibitory networks. Results supported a dependency of inhibitory processing on early lateralized processes. As expected, right-handers showed a stronger N170 over the right hemisphere, and better response inhibition when faces were projected to the right hemisphere. Left-handers showed a stronger N170 over the left hemisphere, and no behavioural asymmetry. Asymmetries in response inhibition were also valence-dependent, with better inhibition of responses to negative faces when projected to the right, and better inhibition of responses to positive faces when projected to the left hemisphere. Frontal asymmetry was not related to handedness, but did modulate response inhibition depending on valence. Consistent with the asymmetric inhibition model (Grimshaw & Carmel, 2014), greater right frontal activity was associated with better response inhibition to positive than to negative faces; subjects with greater left frontal activity showed an opposite trend. These findings highlight the interplay between bottom-up and top-down processes in explaining hemispheric asymmetries in response inhibition., (Copyright © 2020 Elsevier Inc. All rights reserved.)

In human social interaction, affective touch plays an integral role to communicate intentions and emotions. Three of the most important forms of social touch are embracing, cradling and kissing. These behaviours have been demonstrated to be lateralized, but the underlying mechanisms are still not well understood. Both motor and emotive biases have been suggested to affect laterality of social touch. We aimed to systematically investigate how motor preferences and emotive biases influence the lateralization of embracing, cradling and kissing within the same sample. Participants performed all three forms of social touch in neutral, positive and negative emotional conditions. Like a previous study, we found a rightward bias for embracing that was modulated by both motor preferences and the emotional content of the situation. Kissing and cradling were not influenced by motor preferences. In general, a negative emotional connotation of the situation led to a reduction of lateral biases in social touch, independent of the individual direction.

Predator-prey relationships have been suggested to be one of the primary evolutionary factors driving the development of functional hemispheric asymmetries. However, lateralization in many predator species is not well understood and existing studies often are statistically underpowered due to small sample sizes and they moreover show conflicting results. Here, we statistically integrated findings on paw preferences in cats and dogs, two predator species within the Carnivora order that are commonly kept as pets in many societies around the globe. For both species, there were significantly more lateralized than non-lateralized animals. We found that 78% of cats and 68% of dogs showed either left- or right-sided paw preference. Unlike humans, neither dogs nor cats showed a rightward paw preference on the population level. For cats, but not dogs, we found a significant sex difference, with female animals having greater odds of being right-lateralized compared to male animals.

Frontal alpha EEG asymmetry, an indirect marker of asymmetries in relative frontal brain activity, are widely used in research on lateralization of emotional processing. While most authors focus on frontal electrode pairs (e.g., F3/F4 or F7/F8), several recent studies have indicated that EEG asymmetries can also be observed outside the frontal lobe and in frequency bands other than alpha. Because the focus of most EEG asymmetry research is on the correlations between asymmetry and other traits, much less is known about the distribution of patterns of asymmetry at the population level. To systematically assess these asymmetries in a representative sample, we determined EEG asymmetries across the head in the alpha, beta, delta and theta frequency bands in 235 healthy adults. We found significant asymmetries in all four frequency bands and across several brain areas, indicating that EEG asymmetries are not limited to frontal alpha. Asymmetries were not modulated by sex. They were modulated by direction of hand preference, with stronger right-handedness predicting greater right (relative to left) alpha power, or greater left (relative to right) activity. Taken together, the present results show that EEG asymmetries other than frontal alpha represent markers of asymmetric brain function that should be explored further.

The present EEG study investigated the impact of subjective reward preferences and agency on outcome processing. 47 healthy adults (11 male; 36 female) with preferences for either milk or white chocolate completed two runs of a gambling task involving their preferred chocolate (high preference outcomes, HPOs), non-preferred chocolate (medium preference outcomes, MPOs), and a lesser liked non-chocolate reward (low preference outcomes, LPOs). In the 'active' run, subjects chose between three different response options to receive the outcomes. In the 'observational' run, they observed another person's choices and subsequent outcomes. Cluster-based permutation analyses of event-related potential (ERPs) revealed that early processing in the P2 time window reflected outcome salience, differentiating HPOs and MPOs from LPOs, especially for outcomes following own choices, while not distinguishing between HPOs and MPOs. In contrast, processing in later stages, i.e., the typical time windows for feedback-related negativity (FRN) and P300, showed evidence of differential coding of HPOs and MPOs and was also modulated by agency. ERPs clearly differentiated between all three outcome types in the FRN and P300 time windows for outcomes following active but not for observed choices. The present study adds to evidence for modulation of outcome processing by contextual and inter-individual factors. In particular, our findings suggest that subjective preferences are complementarily represented in subjective reward valuation and in motivational value representations indexed by the FRN and the P300., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

The ability to learn from feedback, especially under social scrutiny, is an essential prerequisite for successful interaction with the environment. Patients suffering from social anxiety disorder (SAD) have been proposed to show altered processing of and learning from feedback, especially depending on social context. However, the neural basis and behavioral consequences of altered reinforcement learning in SAD are not clear yet. In the present event-related potentials (ERPs) study, 34 SAD patients and 30 healthy control subjects (HC) performed an adapted version of a probabilistic feedback learning task in two distinct social conditions. In the observation condition, participants were observed by a confederate; in the control condition, they performed the task without being observed. Patients as compared to healthy controls experienced more subjective discomfort under social observation. Moreover, they showed better learning from negative feedback in the control condition, but reduced learning from negative feedback in the observation condition. This effect correlated with reduced differentiation of positive and negative feedback in the time range of the feedback-related negativity (FRN) under high action-feedback contingency. In addition, SAD patients demonstrated increased FRN amplitudes in the first half of the observation condition, in particular to positive feedback. The present results demonstrate that processing of and learning from feedback are altered in SAD, especially under social scrutiny. In particular, it appears that SAD patients do not process positive information adequately on the neural level, which may impair their ability to differentiate between negative and positive outcomes.

This study used a joint flanker task to investigate differences in processing of social and non-social nogo cues, i.e., between cues indicating that a co-actor should respond and cues signaling that neither actor nor co-actor should respond, using event-related potentials (ERPs) and trial-to-trial response times (RTs). It was hypothesized that a social co-actor's response should be reflected in stronger modulation (slower RTs on subsequent trials; augmented neural responses) for social compared to non-social nogo. RTs and ERPs replicated flanker compatibility effects, with faster responses and increased P3a on compatible trials. In line with the hypotheses, ERPs revealed distinct coding of social and non-social nogo in the conflict-sensitive N2 which showed a compatibility effect only for social nogo, and in the attention/memory-related P3b which was larger for social relative to non-social nogo. The P3a did not distinguish between social and non-social nogo, but was larger for compatible and smaller for go trials. Contrary to our hypotheses, RTs were faster after social relative to non-social nogo. Hence, the representation of the co-actor's response in joint action modulates conflict processing reflected in the N2 and response discrimination and evaluation reflected in the P3b and may facilitate subsequent responses in the context of social versus non-social nogo.

Verbal working memory is one of the most studied non-motor functions with robust cerebellar involvement. While the superior cerebellum (lobule VI) has been associated with articulatory control, the inferior cerebellum (lobule VIIIa) has been linked to phonological storage. The present study was aimed to elucidate the differential roles of these regions by investigating whether the cerebellum might contribute to verbal working memory via predictions based on sequence learning/detection. 19 healthy adult subjects completed an fMRI-based Sternberg task which included repeating and novel letter sequences that were phonologically similar or dissimilar. It was hypothesized that learning a repeating sequence of study letters would reduce phonological storage demand and associated right inferior cerebellar activations and that this effect would be modulated by phonological similarity of the study letters. Specifically, while increased phonological storage demand due to high phonological similarity was expected to be reflected in increased right inferior cerebellar activations for similar relative to dissimilar study letters, the reduction in activation for repeating relative to novel sequences was expected to be more profound for phonologically similar than for dissimilar study letters, especially at higher memory load. Results confirmed the typical effects of cognitive load (5 vs. 2 study letters) and phonological similarity in several cerebellar and neocortical brain regions as well as in behavioral data (accuracy and response time). Importantly, activations in superior and inferior cerebellar regions were differentially modulated as a function of similarity and sequence novelty, indicating that particularly lobule VIIIa may contribute to verbal working memory by generating predictions of letter sequences that reduce the likelihood of phonological loop failure before stored items need to be retrieved. The present study is consistent with other investigations that support prediction, which can be based on sequence learning or detection, as an overarching cerebellar function.

Social touch is an important aspect of human social interaction - across all cultures, humans engage in kissing, cradling and embracing. These behaviors are necessarily asymmetric, but the factors that determine their lateralization are not well-understood. Because the hands are often involved in social touch, motor preferences may give rise to asymmetric behavior. However, social touch often occurs in emotional contexts, suggesting that biases might be modulated by asymmetries in emotional processing. Social touch may therefore provide unique insights into lateralized brain networks that link emotion and action. Here, we review the literature on lateralization of cradling, kissing and embracing with respect to motor and emotive bias theories. Lateral biases in all three forms of social touch are influenced, but not fully determined by handedness. Thus, motor bias theory partly explains side biases in social touch. However, emotional context also affects side biases, most strongly for embracing. Taken together, literature analysis reveals that side biases in social touch are most likely determined by a combination of motor and emotive biases., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Previous studies have reported cerebellar activations during error and reward processing. The present study investigated if the cerebellum differentially processes feedback depending on changes in response strategy during reversal learning, as is conceivable given its internal models for movement and thought. Negative relative to positive feedback in an fMRI-based reversal learning task was hypothesized to be associated with increased cerebellar activations. Moreover, increased activations were expected for negative feedback followed by a change in response strategy compared to negative feedback not followed by such a change, and for first positive feedback after compared to final negative feedback before a change, due to updating of internal models. As predicted, activation in lobules VI and VIIa/Crus I was increased for negative relative to positive feedback, and for final negative feedback before a change in response strategy relative to negative feedback not associated with a change. Moreover, activation was increased for first positive feedback after relative to final negative feedback before a change. These findings are consistent with updating of cerebellar internal models to accommodate new behavioral strategies. Recruitment of posterior regions in reversal learning is in line with the cerebellar functional topography, with posterior regions involved in complex motor and cognitive functions., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Purpose: Establishment of regional longitudinal (T 1 ) and transverse (T 2 ) relaxation times in awake pigeons and rats at 7T field strength. Regional differences in relaxation times between species and between two different pigeon breeds (homing pigeons and Figurita pigeons) were investigated., Methods: T 1 and T 2 relaxation times were determined for nine functionally equivalent brain regions in awake pigeons and rats using a multiple spin-echo saturation recovery method with variable repetition time and a multi-slice/multi-echo sequence, respectively. Optimized head fixation and habituation protocols were applied to accustom animals to the scanning conditions and to minimize movement., Results: The habituation protocol successfully limited movement of the awake animals to a negligible minimum, allowing reliable measurement of T 1 and T 2 values within all regions of interest. Significant differences in relaxation times were found between rats and pigeons but not between different pigeon breeds., Conclusion: The obtained T 1 and T 2 values for awake pigeons and rats and the optimized habituation protocol will augment future MRI studies with awake animals. The differences in relaxation times observed between species underline the importance of the acquisition of T 1 /T 2 values as reference points for specific experiments. Magn Reson Med 79:1090-1100, 2018. © 2017 International Society for Magnetic Resonance in Medicine., (© 2017 International Society for Magnetic Resonance in Medicine.)

Previous research suggests that electrophysiological correlates of performance monitoring, in particular the error-related negativity (ERN), vary according to psychopathology and context factors. The present study examined the effect of social context on behavioral and electrophysiological correlates of performance monitoring in healthy adult subjects and in patients with social anxiety disorder (SAD). Participants performed two runs of a Go/NoGo flanker task in different social conditions: in the observation condition, they were observed by a confederate while performing the task, whereas there was no observation in the control condition. Behavioral data showed that accuracy and response times were not modulated by social observation and also did not systematically differ between groups. Post-error slowing was more pronounced in patients, independent of observation condition. ERN amplitudes were generally increased under social observation as compared to the control condition regardless of group (patients, controls). No effects of social context or group were found for PE, NoGo-N2, and NoGo-P3. Exploratory analysis revealed a late sustained parietal negativity to errors in patients as compared to controls. Taken together, the present findings emphasize the importance of social context for the processes underlying performance monitoring. However, the notion of altered error monitoring reflected in an altered ERN in SAD is not supported by our data., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Social anxiety disorder (SAD) is a prevalent and disabling mental disorder, associated with significant psychiatric co-morbidity. Previous research on structural brain alterations associated with SAD has yielded inconsistent results concerning the direction of the changes in gray matter (GM) in various brain regions, as well as on the relationship between brain structure and SAD-symptomatology. These heterogeneous findings are possibly due to limited sample sizes. Multi-site imaging offers new opportunities to investigate SAD-related alterations in brain structure in larger samples. An international multi-center mega-analysis on the largest database of SAD structural T1-weighted 3T MRI scans to date was performed to compare GM volume of SAD-patients ( n  = 174) and healthy control (HC)-participants ( n  = 213) using voxel-based morphometry. A hypothesis-driven region of interest (ROI) approach was used, focusing on the basal ganglia, the amygdala-hippocampal complex, the prefrontal cortex, and the parietal cortex. SAD-patients had larger GM volume in the dorsal striatum when compared to HC-participants. This increase correlated positively with the severity of self-reported social anxiety symptoms. No SAD-related differences in GM volume were present in the other ROIs. Thereby, the results of this mega-analysis suggest a role for the dorsal striatum in SAD, but previously reported SAD-related changes in GM in the amygdala, hippocampus, precuneus, prefrontal cortex and parietal regions were not replicated. Our findings emphasize the importance of large sample imaging studies and the need for meta-analyses like those performed by the Enhancing NeuroImaging Genetics through Meta-Analysis (ENIGMA) Consortium.

Social context influences social decisions and outcome processing, partially depending on inter-individual differences. The present study investigated social context-dependent modulation of behavior and feedback processing in the ultimatum game (UG) in relation to inter-individual differences in social anxiety. Thirty-two healthy adults completed the UG both under social observation and without observation. Offers were allegedly either randomly generated by the computer or drawn from a pool of offers from previous human players. Overall, fewer unfair than fair offers were accepted. Observation decreased acceptance rates for unfair offers. The feedback-locked feedback-related negativity (FRN) but not the P3 was modulated by observation and fairness, with stronger differential coding of unfair/fair under observation. This effect was strongly correlated with individual levels of social anxiety, with higher levels associated with stronger differential fairness coding in the FRN under observation. Behavioral findings support negative reciprocity in the UG, suggesting that (implicit) social norms overwrite explicit task instructions even in the absence of (alleged) social interaction. Observation enhances this effect. Fairness coding in the FRN was modulated by observation as a function of social anxiety, supporting the notion that altered sensitivity to equality in a social context may contribute to social avoidance in socially anxious individuals.

While the cerebellum has traditionally been thought of as mainly involved in motor functions, evidence has been accumulating for cerebellar contributions also to non-motor, cognitive functions. The notion of a cerebellar internal model underlying prediction and processing of sensory events and coordination and fine-tuning of appropriate responses has put the cerebellum right at the interface of motor behavior and cognition. Along these lines, the cerebellum may critically contribute to performance monitoring, a set of cognitive and affective functions underlying adaptive behavior. This review presents and integrates evidence from recent neuroimaging and clinical studies for a cerebellar role in performance monitoring with focus on sensory prediction, error and conflict processing, response inhibition, and feedback learning. Together with evidence for involvement in articulatory monitoring during working memory, these findings suggest monitoring as the cerebellum's overarching function., Competing Interests: The authors have no conflict of interest., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Functional hemispheric asymmetries can vary over time and steroid hormones have been shown to be one of the factors that can modulate them. Research into this matter has mainly focused on sex steroid hormones (androgens, estrogens and progestogens), although there is increasing evidence that glucocorticoids which are related to the body's response to stress (e.g. cortisol or corticosterone) might also modulate functional hemispheric asymmetries. Here, we review studies in humans and non-human model species investigating the relation of stress and laterality. Results indicate a dual relationship of the two parameters. Both acute and chronic stress can affect different forms of lateralization in the human brain, often (but not always) resulting in greater involvement of the right hemisphere. Moreover, lateralization as a form of functional brain architecture can also represent a protective factor against adverse effects of stress., (Copyright © 2016 Elsevier Inc. All rights reserved.)

It has been argued that cerebellar activations during cognitive tasks may masquerade as cognition, while actually reflecting processes related to movement planning or motor learning. The present study investigated whether the cerebellar load effect for verbal working memory, that is, increased activations in lobule VI/Crus I and lobule VIIB/VIIIA, is related to eye movements and oculomotor processing. Fifteen participants performed an fMRI-based Sternberg verbal working memory task. Oculomotor and cognitive task demands were manipulated by using closely and widely spaced stimuli, and high and low cognitive load. Trial-based quantitative eye movement parameters were obtained from concurrent eye tracking. Conventional MRI analysis replicated the cerebellar load effect in lobules VI and VIIB/VIIIa. With quantitative eye movement parameters as regressors, analysis yielded very similar activation patterns. While load effect and eye regressor generally recruited spatially distinct neocortical and cerebellar regions, conjunction analysis showed that a small subset of prefrontal areas implicated in the load effect also responded to the eye regressor. The present results indicate that cognitive load-dependent activations in lateral superior and posteroinferior cerebellar regions in the Sternberg task are independent of eye movements occurring during stimulus encoding. This is inconsistent with the notion that cognitive load-dependent cerebellar activations merely reflect oculomotor processing., (© The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.)

It is as yet unknown if behavioral and neural correlates of performance monitoring in socially anxious individuals are affected by whether feedback is provided by a person or a computer. This fMRI study investigated modulation of feedback processing by feedback source (person vs. computer) in participants with high (HSA) (N=16) and low social anxiety (LSA) (N=16). Subjects performed a choice task in which they were informed that they would receive positive or negative feedback from a person or the computer. Subjective ratings indicated increased arousal and anxiety in HSA versus LSA, most pronounced for social and negative feedback. FMRI analyses yielded hyperactivation in ventral medial prefrontal cortex (vmPFC)/anterior cingulate cortex (ACC) and insula for social relative to computer feedback, and in mPFC/ventral ACC for positive relative to negative feedback in HSA as compared to LSA. These activation patterns are consistent with increased interoception and self-referential processing in social anxiety, especially during processing of positive feedback. Increased ACC activation in HSA to positive feedback may link to unexpectedness of (social) praise as posited in social anxiety disorder (SAD) psychopathology. Activation in rostral ACC showed a reversed pattern, with decreased activation to positive feedback in HSA, possibly indicating altered action values depending on feedback source and valence. The present findings corroborate a crucial role of mPFC for performance monitoring in social anxiety., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Effects of emotional intensity and valence on visual event-related potentials (ERPs) are still poorly understood, in particular in the context of limited attentional resources. In the present EEG study, we investigated the effect of emotional intensity of different emotional facial expressions on P1, N170, early posterior negativity (EPN) and late positive potential (LPP) while varying the amount of available attentional resources. A new stimulus set comprising 90 full color pictures of neutral, happy (low, high intensity), and angry (low, high intensity) expressions was developed. These facial expressions were presented centrally, superimposed by two horizontal bars, and participants engaged in a focal bars task. Availability of attentional resources was varied in two conditions by manipulating the difficulty of the focal bars task (low vs. high perceptual load). Our findings demonstrate intensity and valence effects of task-irrelevant facial expressions on early (N170) and intermediate processing stages (EPN). In addition, task-related effects of perceptual load evolved at intermediate processing stages and were full blown in the time window of LPP. In line with limited resource accounts, valence effects on N170 and EPN were reduced under high perceptual load. Interestingly, apart from this valence by load interaction no further interactions between stimulus and task-driven factors were obtained: Effects of emotional intensity were not modulated by the perceptual load of the focal bars task, indicating that emotional intensity was processed even though attentional resources were heavily restricted., (Copyright © 2016. Published by Elsevier B.V.)