Dorsomedial prefrontal cortex and cerebellar contribution to in-group attitudes: a transcranial magnetic stimulation study

Mapping the mentalizing brain: An ALE meta-analysis to differentiate the representation of social scenes and ages on theory of mind

Theory of mind (ToM) involves understanding others' mental states and relies on brain regions like the temporoparietal junction (TPJ) and medial prefrontal cortex (mPFC). This meta-analytic review categorizes ToM studies into six sub-components across three pairs: (1) Theory of collective mind (ToCM) and individualized theory of mind (iToM), (2) Social intention ToM and private intention ToM, and (3) ToM in adults and ToM in children. We conducted coordinate-based activation likelihood estimation (ALE) analyses and meta-analytic connectivity modeling (MACM) for each sub-component. We found that the ToM components utilized in social or group situations were associated with both the dorsomedial PFC (dmPFC) and right superior temporal sulcus (STS), whereas the ToM components focused on personal concentration were associated with both the lateral PFC and the left STS. The coactivation patterns for the group and age sub-component pairs showed significant spatial overlap with the language networks. These findings indicate that ToM is a multidimensional construct that is related to distinct functional networks for processing each of the ToM sub-components.

Cerebellar Neurostimulation for Boosting Social and Affective Functions: Implications for the Rehabilitation of Hereditary Ataxia Patients

Beyond motor deficits, spinocerebellar ataxia (SCA) patients also suffer cognitive decline and show socio-affective difficulties, negatively impacting on their social functioning. The possibility to modulate cerebello-cerebral networks involved in social cognition through cerebellar neurostimulation has opened up potential therapeutic applications for ameliorating social and affective difficulties. The present review offers an overview of the research on cerebellar neurostimulation for the modulation of socio-affective functions in both healthy individuals and different clinical populations, published in the time period 2000-2022. A total of 25 records reporting either transcranial magnetic stimulation (TMS) or transcranial direct current stimulation (tDCS) studies were found. The investigated clinical populations comprised different pathological conditions, including but not limited to SCA syndromes. The reviewed evidence supports that cerebellar neurostimulation is effective in improving social abilities in healthy individuals and reducing social and affective symptoms in different neurological and psychiatric populations associated with cerebellar damage or with impairments in functions that involve the cerebellum. These findings encourage to further explore the rehabilitative effects of cerebellar neurostimulation on socio-affective deficits experienced by patients with cerebellar abnormalities, as SCA patients. Nevertheless, conclusions remain tentative at this stage due to the heterogeneity characterizing stimulation protocols, study methodologies and patients' samples.

A chronometric study of the posterior cerebellum's function in emotional processing

The posterior cerebellum is a recently discovered hub of the affective and social brain, with different subsectors contributing to different social functions. However, very little is known about when the posterior cerebellum plays a critical role in social processing. Due to its location and anatomy, it has been difficult to use traditional approaches to directly study the chronometry of the cerebellum. To address this gap in cerebellar knowledge, here we investigated the causal contribution of the posterior cerebellum to social processing using a chronometric transcranial magnetic stimulation (TMS) approach. We show that the posterior cerebellum is recruited at an early stage of emotional processing (starting from 100 ms after stimulus onset), simultaneously with the posterior superior temporal sulcus (pSTS), a key node of the social brain. Moreover, using a condition-and-perturb TMS approach, we found that the recruitment of the pSTS in emotional processing is dependent on cerebellar activation. Our results are the first to shed light on chronometric aspects of cerebellar function and its causal functional connectivity with other nodes of the social brain.

A meta-analysis of non-invasive brain stimulation (NIBS) effects on cerebellar-associated cognitive processes

Non-invasive brain stimulation (NIBS) techniques, including transcranial magnetic stimulation (TMS) and transcranial electrical stimulation (tES), have provided valuable insights into the role of the cerebellum in cognitive processes. However, replicating findings from studies involving cerebellar stimulation poses challenges. This meta-analysis investigates the impact of NIBS on cognitive processes associated with the cerebellum. We conducted a systematic search and analyzed 66 studies and 91 experiments involving healthy adults who underwent either TMS or transcranial direct current stimulation (tDCS) targeting the cerebellum. The results indicate that anodal tDCS applied to the medial cerebellum enhances cognitive performance. In contrast, high-frequency TMS disrupts cognitive performance when targeting the lateral cerebellar hemispheres or when employed in online protocols. Similarly, low-frequency TMS and continuous theta burst stimulation (cTBS) diminish performance in offline protocols. Moreover, high-frequency TMS impairs accuracy. By identifying consistent effects and moderators of modulation, this meta-analysis contributes to improving the replicability of studies using NIBS on the cerebellum and provides guidance for future research aimed at developing effective NIBS interventions targeting the cerebellum.

High-frequency repetitive transcranial magnetic stimulation (HF-rTMS) on global cognitive function of elderly in mild to moderate Alzheimer's disease: a systematic review and meta-analysis

OBJECTIVE

High-frequency repetitive transcranial magnetic stimulation (HF-rTMS) is a non-invasive brain stimulation technique used to improve cognitive deficits in patients with Alzheimer's disease (AD). This systematic review and meta-analysis aimed to evaluate the efficacy of HF-rTMS in improving global cognitive function rehabilitation in elderly patients with mild to moderate AD.

METHODS

A detailed literature search of publications using ten databases (Chinese: Wanfang, VIP Periodical, SinoMed, the Chinese National Knowledge Infrastructure; English: PubMed, Embase, OVID, Web of Science, Cochrane Library, and EBSCOhost) was performed to identify English and Chinese language articles published up to December 2022. We only included randomized controlled trials (RCTs) that evaluate the effect of HF-rTMS on elderly patients with mild to moderate AD. The retrieved studies were carefully reviewed, extracted data, and assessed quality.

RESULTS

Seventeen studies, including 1161 elderly patients with mild to moderate AD, were included in this meta-analysis. Compared to the control group, HF-rTMS could increase MMSE (mean difference [MD] = 3.64; 95%CI 1.86-5.42; P < 0.0001), MoCA (MD = 3.69; 95%CI 1.84-5.54; P < 0.0001), P300 amplitude (MD = 1.09; 95%CI 0.45-1.72; P = 0.0008), and total effective rate scores (MD = 3.64; 95% CI 2.14-6.18; P < 0.00001) while decreasing ADAS-Cog (MD =  - 3.53; 95%CI - 4.91- - 2.15; P < 0.00001) and P300 latency scores (MD =  - 38.32; 95%CI - 72.40- - 4.24; P = 0.03). Our study showed that HF-rTMS could improve the global cognitive function of elderly patients with mild to moderate AD.

CONCLUSION

HF-rTMS can improve global cognitive function in elderly patients with mild to moderate AD, which is an effective and safe rehabilitation treatment tool for AD patients.

Resting-state functional connectivity of the cerebellum-cerebrum in older women with depressive symptoms

BACKGROUND

Although there has been much neurobiological research on major depressive disorder, research on the neurological function of depressive symptoms (DS) or subclinical depression is still scarce, especially in older women with DS.

OBJECTIVES

Resting-state functional magnetic resonance imaging (rs-fMRI) was used to compare functional connectivity (FC) between the cerebellum and cerebral in older women with DS and normal controls (NC), to explore unique changes in cerebellar FC in older women with DS.

METHODS

In all, 16 older women with DS and 17 NC were recruited. All subjects completed rs-fMRI. The 26 sub-regions of the cerebellum divided by the AAL3 map were used as regions of interest (ROI) to analyze the difference in FC strength of cerebellar seeds from other cerebral regions between the two groups. Finally, partial correlation analysis between abnormal FC strength and Geriatric Depression Scale (GDS) score and Reminiscence Functions Scale (RFS) score in the DS group.

RESULTS

Compared with NC group, the DS group showed significantly reduced FC between Crus I, II and the left frontoparietal region, and reduced FC between Crus I and the left temporal gyrus. Reduced FC between right insula (INS), right rolandic operculum (ROL), right precentral gyrus (PreCG) and the Lobule IX, X. Moreover, the negative FC between Crus I, II, Lobule IX and visual regions was reduced in the DS group. The DS group correlation analysis showed a positive correlation between the left Crus I and the right cuneus (CUN) FC and GDS. In addition, the abnormal FC strength correlated with the scores in different dimensions of the RFS, such as the negative FC between the Crus I and the left middle temporal gyrus (MTG) was positively associated with intimacy maintenance, and so on.

CONCLUSION

Older women with DS have anomalous FC between the cerebellum and several regions of the cerebrum, which may be related to the neuropathophysiological mechanism of DS in the DS group.

Functional role of the theory of mind network in integrating mentalistic prior information with action kinematics during action observation

Inferring intentions from verbal and nonverbal human behaviour is critical for everyday social life. Here, we combined Transcranial Magnetic Stimulation (TMS) with a behavioural priming paradigm to test whether key nodes of the Theory of Mind network (ToMn) contribute to understanding others' intentions by integrating prior knowledge about an agent with the observed action kinematics. We used a modified version of the Faked-Action Discrimination Task (FAD), a forced-choice paradigm in which participants watch videos of actors lifting a cube and judge whether the actors are trying to deceive them concerning the weight of the cube. Videos could be preceded or not by verbal description (prior) about the agent's truthful or deceitful intent. We applied single pulse TMS over three key nodes of the ToMn, namely dorsomedial prefrontal cortex (dmPFC), right posterior superior temporal sulcus (pSTS) and right temporo-parietal junction (rTPJ). Sham-TMS served as a control (baseline) condition. Following sham or rTPJ stimulation, we observed no consistent influence of priors on FAD performance. In contrast, following dmPFC stimulation, and to a lesser extent pSTS stimulation, truthful and deceitful actions were perceived as more deceptive only when the prior suggested a dishonest intention. These findings highlight a functional role of dmPFC and pSTS in coupling prior knowledge about deceptive intents with observed action kinematics in order to judge faked actions. Our study provides causal evidence that fronto-temporal nodes of the ToMn are functionally relevant to mental state inference during action observation.

Cerebellar contribution to emotional body language perception: a TMS study

Consistent evidence suggests that the cerebellum contributes to the processing of emotional facial expressions. However, it is not yet known whether the cerebellum is recruited when emotions are expressed by body postures or movements, or whether it is recruited differently for positive and negative emotions. In this study, we asked healthy participants to discriminate between body postures (with masked face) expressing emotions of opposite valence (happiness vs anger, Experiment 1), or of the same valence (negative: anger vs sadness; positive: happiness vs surprise, Experiment 2). While performing the task, participants received online transcranial magnetic stimulation (TMS) over a region of the posterior left cerebellum and over two control sites (early visual cortex and vertex). We found that TMS over the cerebellum affected participants' ability to discriminate emotional body postures, but only when one of the emotions was negatively valenced (i.e. anger). These findings suggest that the cerebellar region we stimulated is involved in processing the emotional content conveyed by body postures and gestures. Our findings complement prior evidence on the role of the cerebellum in emotional face processing and have important implications from a clinical perspective, where non-invasive cerebellar stimulation is a promising tool for the treatment of motor, cognitive and affective deficits.

Distinct cerebellar regions for body motion discrimination

Visual processing of human movements is critical for adaptive social behavior. Cerebellar activations have been observed during biological motion discrimination in prior neuroimaging studies, and cerebellar lesions may be detrimental for this task. However, whether the cerebellum plays a causal role in biological motion discrimination has never been tested. Here, we addressed this issue in three different experiments by interfering with the posterior cerebellar lobe using transcranial magnetic stimulation (TMS) during a biological discrimination task. In Experiments 1 and 2, we found that TMS delivered at onset of the visual stimuli over the vermis (vermal lobule VI), but not over the left cerebellar hemisphere (left lobule VI/Crus I), interfered with participants' ability to distinguish biological from scrambled motion compared to stimulation of a control site (vertex). Interestingly, when stimulation was delivered at a later time point (300 ms after stimulus onset), participants performed worse when TMS was delivered over the left cerebellar hemisphere compared to the vermis and the vertex (Experiment 3). Our data show that the posterior cerebellum is causally involved in biological motion discrimination and suggest that different sectors of the posterior cerebellar lobe may contribute to the task at different time points.

The Role of the Posterior Cerebellum in Dysfunctional Social Sequencing

Recent advances in social neuroscience have highlighted the critical role of the cerebellum in social cognition, and especially the posterior cerebellum. Studies have supported 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 are to these actions. This mechanism allows to better anticipate action sequences during social interactions in an automatic and intuitive way and to fine-tune these anticipations, making it easier to understand other's social behaviors and mental states (e.g., beliefs, intentions, traits). In this paper, we argue that the central role of the posterior cerebellum in identifying and automatizing social action sequencing provides a fruitful starting point for investigating social dysfunctions in a variety of clinical pathologies, such as autism, obsessive-compulsive and bipolar disorder, depression, and addiction. Our key hypothesis is that dysfunctions of the posterior cerebellum lead to under- or overuse of inflexible social routines and lack of plasticity for learning new, more adaptive, social automatisms. We briefly review past research supporting this view and propose a program of research to test our hypothesis. This approach might alleviate a variety of mental problems of individuals who suffer from inflexible automatizations that stand in the way of adjustable and intuitive social behavior, by increasing posterior cerebellar plasticity using noninvasive neurostimulation or neuro-guided training programs.

Probing cerebellar involvement in cognition through a meta-analysis of TMS evidence

Traditionally, the cerebellum has been linked to motor coordination, but growing evidence points to its involvement in a wide range of non-motor functions. Though the number of studies using transcranial magnetic stimulation (TMS) to investigate cerebellar involvement in cognitive processes is growing exponentially, these findings have not yet been synthesized in a meta-analysis. Here, we used meta-analysis to estimate the effects of cerebellar TMS on performance in cognitive tasks for healthy participants. Outcomes included participants' accuracy and response times (RTs) of several non-motor tasks performed either during or after the administration of TMS. We included overall 41 studies, of which 44 single experiments reported effects on accuracy and 41 on response times (RTs). The meta-analyses showed medium effect sizes (for accuracy: d = 0.61 [95% CI = 0.48, .073]; for RTs: d = 0.40 [95% CI = 0.30, 0.49]), with leave-one-out analyses indicating that cumulative effects were robust, and with moderate heterogeneity. For both accuracy and RTs, the effect of TMS was moderated by the stimulation paradigm adopted but not by the cognitive function investigated, while the timing of the stimulation moderated only the effects on RTs. Further analyses on lateralization revealed no moderation effects of the TMS site. Taken together, these findings indicate that TMS administered over the cerebellum is able to modulate cognitive performance, affecting accuracy or RTs, and suggest that the various stimulation paradigms play a key role in determining the efficacy of cerebellar TMS.

New Horizons on Non-invasive Brain Stimulation of the Social and Affective Cerebellum

The cerebellum is increasingly attracting scientists interested in basic and clinical research of neuromodulation. Here, we review available studies that used either transcranial magnetic stimulation (TMS) or transcranial direct current stimulation (tDCS) to examine the role of the posterior cerebellum in different aspects of social and affective cognition, from mood regulation to emotion discrimination, and from the ability to identify biological motion to higher-level social inferences (mentalizing). We discuss how at the functional level the role of the posterior cerebellum in these different processes may be explained by a generic prediction mechanism and how the posterior cerebellum may exert this function within different cortico-cerebellar and cerebellar limbic networks involved in social cognition. Furthermore, we suggest to deepen our understanding of the cerebro-cerebellar circuits involved in different aspects of social cognition by employing promising stimulation approaches that have so far been primarily used to study cortical functions and networks, such as paired-pulse TMS, frequency-tuned stimulation, state-dependent protocols, and chronometric TMS. The ability to modulate cerebro-cerebellar connectivity opens up possible clinical applications for improving impairments in social and affective skills associated with cerebellar abnormalities.

The posterior crus II cerebellum is specialized for social mentalizing and emotional self-experiences: a meta-analysis

This meta-analysis explores the role of the posterior cerebellum Crus I/II in social mentalizing. We identified over 200 functional magnetic resonance imaging (fMRI) studies via NeuroSynth that met our inclusion criteria and fell within bilateral Crus II areas related to ‘sequencing’ during mentalizing (coordinates ±24 −76 −40; from earlier studies) and mere social ‘mentalizing’ or self-related emotional cognition (coordinates ±26 −84 −34; from NeuroSynth), located in the cerebellar mentalizing network. A large majority of these studies (74%) involved mentalizing or self-related emotional cognition. Other functions formed small minorities. This high incidence in Crus II compares very favorably against the lower base rate for mentalizing and self-related emotions (around 35%) across the whole brain as revealed in NeuroSynth. In contrast, there was much less support for a similar role of Crus I (coordinates −40 −70 −40 from earlier ‘sequencing’ studies) as only 35% of the studies were related to mentalizing or self-related emotions. The present findings show that a domain-specific social mentalizing functionality is supported in the cerebellar Crus II. This has important implications for theories of the social cerebellum focusing on sequencing of social actions, and for cerebellar neurostimulation treatments.

Cortical plasticity is correlated with cognitive improvement in Alzheimer's disease patients after rTMS treatment

OBJECTIVE

Repetitive transcranial magnetic stimulation (rTMS) has been widely used in non-invasive treatments for different neurological disorders. Few biomarkers are available for treatment response prediction. This study aims to analyze the correlation between changes in long-term potentiation (LTP)-like cortical plasticity and cognitive function in patients with Alzheimer's disease (AD) that underwent rTMS treatment.

METHODS

A total of 75 AD patients were randomized into either 20 Hz rTMS treatment at the dorsolateral prefrontal cortex (DLPFC) group (n = 37) or a sham treatment group (n = 38) for 30 sessions over six weeks (five days per week) with a three-month follow-up. Neuropsychological assessments were conducted using the Mini-Mental State Examination (MMSE) and Alzheimer's Disease Assessment-Cognitive Component (ADAS-Cog). The cortical plasticity reflected by the motor-evoked potential (MEP) before and after high-frequency repetitive TMS to the primary motor cortex (M1) was also examined prior to and after the treatment period.

RESULTS

The results showed that the cognitive ability of patients who underwent the MMSE and ADAS-Cog assessments showed small but significant improvement after six weeks of rTMS treatment compared with the sham group. The cortical plasticity improvement correlated to the observed cognition change.

CONCLUSIONS

Cortical LTP-like plasticity could predict the treatment responses of cognitive improvements in AD patients receiving rTMS intervention. This warrants future clinical trials using cortical LTP as a predictive marker.

Consensus Paper: Cerebellum and Social Cognition

The traditional view on the cerebellum is that it controls motor behavior. Although recent work has revealed that the cerebellum supports also nonmotor functions such as cognition and affect, only during the last 5 years it has become evident that the cerebellum also plays an important social role. This role is evident in social cognition based on interpreting goal-directed actions through the movements of individuals (social "mirroring") which is very close to its original role in motor learning, as well as in social understanding of other individuals' mental state, such as their intentions, beliefs, past behaviors, future aspirations, and personality traits (social "mentalizing"). Most of this mentalizing role is supported by the posterior cerebellum (e.g., Crus I and II). The most dominant hypothesis is that the cerebellum assists in learning and understanding social action sequences, and so facilitates social cognition by supporting optimal predictions about imminent or future social interaction and cooperation. This consensus paper brings together experts from different fields to discuss recent efforts in understanding the role of the cerebellum in social cognition, and the understanding of social behaviors and mental states by others, its effect on clinical impairments such as cerebellar ataxia and autism spectrum disorder, and how the cerebellum can become a potential target for noninvasive brain stimulation as a therapeutic intervention. We report on the most recent empirical findings and techniques for understanding and manipulating cerebellar circuits in humans. Cerebellar circuitry appears now as a key structure to elucidate social interactions.

Nonlinear interaction between stimulation intensity and initial brain state: Evidence for the facilitatory/suppressive range model of online TMS effects

The effects of online Transcranial Magnetic Stimulation (TMS) can qualitatively vary as a function of brain state. For example, TMS intensities which normally impair performance can have a facilitatory effect if the targeted neuronal representations are in a suppressed state. These phenomena have been explained in terms of the existence of distinct facilitatory and suppressive ranges as a function of TMS intensity which are shifted by changes in neural excitability. We tested this model by applying TMS at a low (60 % of phosphene threshold) or high (120 % of phosphene threshold) intensity during a priming paradigm. Our results show that state-dependent TMS effects vary qualitatively as a function of TMS intensity. Whereas the application of TMS at 120 % of participants' phosphene threshold impaired performance on fully congruent trials (in effect, reducing the benefit of priming), TMS applied at a lower intensity (60 % of phosphene threshold), facilitated performance on congruent trials. These results demonstrate that behavioral effects of TMS reflect a nonlinear interaction between initial activation state and TMS intensity. They also provide support for the existence of facilitatory/suppressive ranges of TMS effects which shift when neural excitability changes.

A causal role for the cerebellum in semantic integration: a transcranial magnetic stimulation study

Mounting evidence suggests that the cerebellum, a structure previously linked to motor function, is also involved in a wide range of non-motor processes. It has been proposed that the cerebellum performs the same computational processes in both motor and non-motor domains. Within motor functions, the cerebellum is involved in the integration of signals from multiple systems. Here we hypothesized that cerebellum may be involved in integration within semantic memory as well. Specifically, understanding a noun-adjective combination (e.g. red apple) requires combining the meaning of the adjective (red) with the meaning of the noun (apple). In two experiments, participants were asked to judge whether noun-adjective word-pairs were semantically related (e.g., red apple) or not (e.g., lucky milk) while online transcranial magnetic stimulation (TMS) was administered over the right cerebellum or over a control site (vertex in Experiment 1 and visual cortex in Experiment 2). Cerebellar TMS caused a decrease in participants’ accuracy for related word-pairs while accuracy for unrelated stimuli was not affected. A third experiment using a control task where subjects compared pairs of random letters showed no effect of TMS. Taken together these results indicate that the right cerebellum is involved specifically in the processing of semantically related stimuli. These results are consistent with theories that proposed the existence of a unified cerebellar function within motor and non-motor domains, as well with recent perspectives about cerebellar involvement in semantic memory and predictive cognition.

TMS over the posterior cerebellum modulates motor cortical excitability in response to facial emotional expressions

Evidence suggests that the posterior cerebellum is involved in emotional processing. Specific mechanisms by which the cerebellum contributes to the perception of and reaction to the emotional state of others are not well-known. It is likely that perceived emotions trigger anticipatory/preparatory motor changes. However, the extent to which the cerebellum modulates the activity of the motor cortex to contribute to emotional processing has not been directly investigated. In this study, we assessed whether the activity of the posterior cerebellum influences the modulation of motor cortical excitability in response to emotional stimuli. To this end, we transiently disrupted the neural activity of the left posterior cerebellum using 1 Hz repetitive transcranial magnetic stimulation (rTMS) and examined its effect on motor cortical excitability witnessed during emotional face processing (in comparison to the effects of sham rTMS). Motor excitability was measured as TMS-based motor evoked potentials (MEPs) recorded from bilateral first dorsal interosseous (FDI) muscles during the viewing of negative emotional (i.e. fearful) and neutral facial expressions. In line with previous evidence, we found that MEP amplitude was increased during the viewing of fearful compared to neutral faces. Critically, when left posterior cerebellar activity was transiently inhibited with 1 Hz rTMS, we observed a reduction in amplitude of MEPs recorded from the contralateral (right) motor cortex during the viewing of emotional (but not neutral) faces. In turn, inhibition of the left posterior cerebellum did not affect the amplitude of MEPs recorded from the ipsilateral motor cortex. Our findings suggest that the posterolateral (left) cerebellum modulates motor cortical response to negative emotional stimuli and may serve as an interface between limbic, cognitive, and motor systems.

The Cerebellar Cognitive Affective/Schmahmann Syndrome: a Task Force Paper

Sporadically advocated over the last two centuries, a cerebellar role in cognition and affect has been rigorously established in the past few decades. In the clinical domain, such progress is epitomized by the "cerebellar cognitive affective syndrome" ("CCAS") or "Schmahmann syndrome." Introduced in the late 1990s, CCAS reflects a constellation of cerebellar-induced sequelae, comprising deficits in executive function, visuospatial cognition, emotion-affect, and language, over and above speech. The CCAS thus offers excellent grounds to investigate the functional topography of the cerebellum, and, ultimately, illustrate the precise mechanisms by which the cerebellum modulates cognition and affect. The primary objective of this task force paper is thus to stimulate further research in this area. After providing an up-to-date overview of the fundamental findings on cerebellar neurocognition, the paper substantiates the concept of CCAS with recent evidence from different scientific angles, promotes awareness of the CCAS as a clinical entity, and examines our current insight into the therapeutic options available. The paper finally identifies topics of divergence and outstanding questions for further research.

Group membership dictates the neural correlates of social optimism biases

Optimism bias, i.e. expecting the future to hold more desirable than undesirable outcomes, also extends to people that we like or admire. However, it remains unknown how the brain generates this social optimism bias. In this study, respondents estimated the likelihood of future desirable and undesirable outcomes for an in-group and three out-groups: warm-incompetent, cold-competent, and cold-incompetent. We found a strong social optimism bias for the in-group and the warm out-group and an inverted pattern for the cold-incompetent out-group. For all groups, scores of social optimism bias correlated with the brain activity in structures that respondents differentially engaged depending on the target social group. In line with our hypotheses, evaluating the in-group recruited the ventromedial prefrontal cortex and the precuneus/posterior cingulate cortex, whereas evaluating the warm out-group engaged the posterior insula, mid cingulate cortex, and somatosensory cortices. These findings suggest different underlying cognitive mechanisms of social optimism bias for these groups, despite similar behavioural patterns. Thinking about the cold out-groups recruited the right anterior temporal lobe, and temporoparietal junction. Evaluating the cold-incompetent out-group additionally recruited the anterior insula, inferior frontal cortex and dorsomedial frontal cortex. We discuss these neuroimaging findings with respect to their putative cognitive functions.

The Cerebellar Cognitive Affective/Schmahmann Syndrome: a Task Force Paper

Sporadically advocated over the last two centuries, a cerebellar role in cognition and affect has been rigorously established in the past few decades. In the clinical domain, such progress is epitomized by the "cerebellar cognitive affective syndrome" ("CCAS") or "Schmahmann syndrome." Introduced in the late 1990s, CCAS reflects a constellation of cerebellar-induced sequelae, comprising deficits in executive function, visuospatial cognition, emotion-affect, and language, over and above speech. The CCAS thus offers excellent grounds to investigate the functional topography of the cerebellum, and, ultimately, illustrate the precise mechanisms by which the cerebellum modulates cognition and affect. The primary objective of this task force paper is thus to stimulate further research in this area. After providing an up-to-date overview of the fundamental findings on cerebellar neurocognition, the paper substantiates the concept of CCAS with recent evidence from different scientific angles, promotes awareness of the CCAS as a clinical entity, and examines our current insight into the therapeutic options available. The paper finally identifies topics of divergence and outstanding questions for further research.

Social, self, (situational), and affective processes in medial prefrontal cortex (MPFC): Causal, multivariate, and reverse inference evidence

The medial prefrontal cortex (MPFC) has been posited to serve a variety of social, affective, and cognitive functions. These conclusions have largely been driven by forward inference analyses (e.g. GLM fMRI studies and meta-analyses) that indicate where domain-specific tasks tend to produce activity but tell us little about what those regions do. Here, we take a multi-method, multi-domain approach to the functionality of MPFC subdivisions within Brodmann areas 9-11. We consider four methods that each have reverse inference or causal inference value: lesion work, transcranial magnetic stimulation, multivariate pattern analysis, and Neurosynth analyses. The Neurosynth analyses include multi-term reverse inference analyses that compare several domains of interest to one another at once. We examine the evidence supporting structure-function links in five domains: social cognition, self, value, emotional experience, and mental time travel. The evidence is considered for each of three MPFC subdivisions: dorsomedial prefrontal cortex (DMPFC), anteromedial prefrontal cortex (AMPFC), and ventromedial prefrontal cortex (VMPFC). Although there is evidentiary variability across methods, the results suggest that social processes are functionally linked to DMPFC (and somewhat surprisingly in VMPFC), self processes are linked to AMPFC, and affective processes are linked to AMPFC and VMPFC. There is also a relatively non-selective region of VMPFC that may support situational processing, a process key to each domain, but also independent of each.

Insights From fMRI Studies Into Ingroup Bias

Intergroup biases can manifest themselves between a wide variety of different groups such as people from different races, nations, ethnicities, political or religious beliefs, opposing sport teams or even arbitrary groups. In this review we provide a neuroscientific overview of functional Magnetic Resonance Imaging (fMRI) studies that have revealed how group dynamics impact on various cognitive and emotional systems at different levels of information processing. We first describe how people can perceive the faces, words and actions of ingroup and outgroup members in a biased way. Second, we focus on how activity in brain areas involved in empathizing with the pain of others, such as the dorsal anterior cingulate cortex (dACC) and anterior insula (AI), are influenced by group membership. Third, we describe how group membership influences activity in brain areas involved in mentalizing such as the medial prefrontal cortex (mPFC) and temporoparietal junction (TPJ). Fourth, we discuss the involvement of the lateral orbitofrontal cortex (lOFC) in increased moral sensitivity for outgroup threats. Finally, we discuss how brain areas involved in the reward system such as the striatum and medial orbitofrontal cortex (mOFC), are more active when experiencing schadenfreude for outgroup harm and when rewarding ingroup (versus outgroup) members. The value of these neuroscientific insights to better understand ingroup bias are discussed, as well as limitations and future research directions.

TMS Over the Cerebellum Interferes with Short-term Memory of Visual Sequences

Growing evidence suggests that the cerebellum is not only involved in motor functions, but it significantly contributes to sensory and cognitive processing as well. In particular, it has been hypothesized that the cerebellum identifies recurrent serial events and recognizes their violations. Here we used transcranial magnetic stimulation (TMS) to shed light on the role of the cerebellum in short-term memory of visual sequences. In two experiments, we found that TMS over the right cerebellar hemisphere impaired participants' ability to recognize the correct order of appearance of geometrical stimuli varying in shape and/or size. In turn, cerebellar TMS did not affect recognition of highly familiar short sequences of letters or numbers. Overall, our data suggest that the cerebellum is involved in memorizing the order in which (concatenated) stimuli appear, this process being important for sequence learning.

The role of the cerebellum in explicit and incidental processing of facial emotional expressions: A study with transcranial magnetic stimulation

Growing evidence suggests that the cerebellum plays a critical role in non-motor functions, contributing to cognitive and affective processing. In particular, the cerebellum might represent an important node of the "limbic" network, underlying not only emotion regulation but also emotion perception and recognition. Here, we used transcranial magnetic stimulation (TMS) to shed further light on the role of the cerebellum in emotional perception by specifically testing cerebellar contribution to explicit and incidental emotional processing. In particular, in three different experiments, we found that TMS over the (left) cerebellum impaired participants' ability to categorize facial emotional expressions (explicit task) and to classify the gender of emotional faces (incidental emotional processing task), but not the gender of neutral faces. Overall, our results indicate that the cerebellum is involved in perceiving the emotional content of facial stimuli, even when this is task irrelevant.