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In mediated interactions (e.g. video calls), less information is available about the other. To investigate how this affects our empathy for one another, we conducted an electroencephalogram study, in which 30 human participants observed 1 of 5 targets undergoing painful electric stimulation, once in a direct interaction and once in a live, video-mediated interaction. We found that observers were as accurate in judging others' pain and showed as much affective empathy via video as in a direct encounter. While mu suppression, a common neural marker of empathy, was not sensitive to others' pain, theta responses to others' pain as well as skin conductance coupling between participants were reduced in the video-mediated condition. We conclude that physical proximity with its rich social cues is important for nuanced physiological resonance with the other's experience. More studies are warranted to confirm these results and to understand their behavioral significance for remote social interactions.
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Empatía , Dolor , Humanos , Dolor/psicología , ElectroencefalografíaRESUMEN
In social interactions, emotional biases can arise when the emotional state of oneself and another person are incongruent. A person's ability to judge the other's emotional state can then be biased by their own emotional state, leading to an emotional egocentric bias (EEB). Alternatively, a person's perception of their own emotional state can be biased by the other's emotional state leading to an emotional altercentric bias (EAB). Using a modified audiovisual paradigm, we examined in three studies (n = 171; two online & one lab-based study) whether emotional biases can be considered traits by measuring two timepoints within participant and relating empathy trait scores to emotional biases, as well as the electrophysiological correlates of emotional biases. In all studies, we found a congruency effect, reflecting an EEB and EAB of small size. Both biases failed to correlate significantly within participants across timepoints and did not display significant relationships with empathy trait scores. On the electrophysiological level, we did not find any neural emotional bias effects in the time-frequency domain. Our results suggest that EEB and EAB effects are strongly task sensitive. Caution is warranted when studying interindividual differences in emotional biases using this paradigm, as they did not show significant test-retest reliabilities.
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Emociones , Empatía , Humanos , Emociones/fisiología , Sesgo , EgoRESUMEN
When meeting other people, some are optimistic and expect to be accepted by others, whereas others are pessimistic and expect mostly rejections. How social feedback is evaluated in situations that meet or do not meet these biases and how people differ in their response to rejection and acceptance depending on the social situation are unknown. In this study, participants experienced rejection and acceptance by peers in two different social contexts, one with high (negative context) and the other with low probability of rejection (positive context). We examined how the neural and behavioral responses to rejection are altered by this context and whether it depends on the individual's sensitivity to rejection. Behavioral results show that, on average, people maintain an optimistic bias even when mostly experiencing rejection. Importantly, personality differences in rejection sensitivity affected both prior expectations to be rejected in the paradigm and the extent to which expectations changed during the paradigm. The context also strongly modulated ERPs and theta responses to rejection and acceptance feedback. Specifically, valence effects on neural responses were enhanced in the negative context, suggesting a greater relevance to monitor social feedback in such a situation. Moreover, midfrontal theta predicted how expectations were changed in response to prediction errors, stressing a role for theta in learning from social feedback. Surprisingly, interindividual differences in rejection sensitivity did not affect neural responses to feedback. Our results stress the importance of considering the interaction between subjective expectations and the social context for behavioral and neural responses to social rejection.
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Motivación , Distancia Psicológica , Potenciales Evocados/fisiología , Retroalimentación , Humanos , Medio SocialRESUMEN
Several studies suggest a link between acute changes in inflammatory parameters due to an endotoxin or (psychological) stressor and the brain's stress response. The extent to which basal circulating levels of inflammatory markers are associated with the brain's stress response has been hardly investigated so far. In the present study, baseline plasma levels of the cytokine interleukin (IL)-6 were obtained and linked to neural markers of psychosocial stress using a modified version of the Montreal Imaging Stress Task in a sample of N = 65 healthy subjects (N = 39 female). Of three a-priori defined regions of interest - the amygdala, anterior insula, and anterior cingulate cortex - baseline IL-6 was significantly and negatively associated with stress-related neural activation in the right amygdala and left anterior insula. Our results suggest that baseline cytokines might be related to differences in the neural stress response and that this relationship could be inverse to that previously reported for induced acute changes in inflammation markers.
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Amígdala del Cerebelo , Interleucina-6 , Adulto , Amígdala del Cerebelo/diagnóstico por imagen , Amígdala del Cerebelo/metabolismo , Citocinas , Femenino , Giro del Cíngulo/diagnóstico por imagen , Humanos , Interleucina-6/sangre , Imagen por Resonancia Magnética/métodos , Estrés Psicológico/sangreRESUMEN
Previous research provided evidence for the critical importance of the PFC and BG for reactive motor inhibition, that is, when actions are cancelled in response to external signals. Less is known about the role of the PFC and BG in proactive motor inhibition, referring to preparation for an upcoming stop signal. In this study, patients with unilateral lesions to the BG or lateral PFC performed in a cued go/no-go task, whereas their EEG was recorded. The paradigm called for cue-based preparation for upcoming, lateralized no-go signals. Based on previous findings, we focused on EEG indices of cognitive control (prefrontal beta), motor preparation (sensorimotor mu/beta, contingent negative variation [CNV]), and preparatory attention (occipital alpha, CNV). On a behavioral level, no differences between patients and controls were found, suggesting an intact ability to proactively prepare for motor inhibition. Patients showed an altered preparatory CNV effect, but no other differences in electrophysiological activity related to proactive and reactive motor inhibition. Our results suggest a context-dependent role of BG and PFC structures in motor inhibition, being critical in reactive, unpredictable contexts, but less so in situations where one can prepare for stopping on a short timescale.
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Inhibición Psicológica , Corteza Prefrontal , Atención , Ganglios Basales , Humanos , Inhibición Proactiva , Tiempo de Reacción , Inhibición ReactivaRESUMEN
Damage to the ventromedial PFC (VMPFC) can cause maladaptive social behavior, but the cognitive processes underlying these behavioral changes are still uncertain. Here, we tested whether patients with acquired VMPFC lesions show altered approach-avoidance tendencies to emotional facial expressions. Thirteen patients with focal VMPFC lesions and 31 age- and gender-matched healthy controls performed an implicit approach-avoidance task in which they either pushed or pulled a joystick depending on stimulus color. Whereas controls avoided angry faces, VMPFC patients displayed an incongruent response pattern characterized by both increased approach and reduced avoidance of angry facial expressions. The approach bias was stronger in patients with higher self-reported impulsivity and disinhibition and in those with larger lesions. We further used linear ballistic accumulator modeling to investigate latent parameters underlying approach-avoidance decisions. Controls displayed negative drift rates when approaching angry faces, whereas VMPFC lesions abolished this pattern. In addition, VMPFC patients had weaker response drifts than controls during avoidance. Finally, patients showed reduced drift rate variability and shorter nondecision times, indicating impulsive and rigid decision-making. Our findings thus suggest that VMPFC damage alters the pace of evidence accumulation in response to social signals, eliminating a default, protective avoidant bias and facilitating a dysfunctional approach behavior.
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Emociones , Expresión Facial , Conducta de Elección , Humanos , Conducta Impulsiva , Corteza Prefrontal/diagnóstico por imagen , PrejuicioRESUMEN
Alpha oscillations (8-13 Hz) have been suggested to play an important role in dynamic neural processes underlying learning and memory. The goal of this study was to scrutinize the role of alpha oscillations in communication within a cortico-cerebellar network implicated in motor sequence learning. To this end, we conducted two EEG experiments using a serial reaction time task. In the first experiment, we explored changes in alpha power and cross-channel alpha coherence as subjects learned a motor sequence. We found a gradual decrease in spectral alpha power over left premotor cortex (PMC) and sensorimotor cortex (SM1) during learning blocks. In addition, alpha coherence between left PMC/SM1 and left cerebellar crus I was specifically decreased during sequence learning, possibly reflecting a functional decoupling in the broader motor learning network. In the second experiment in a different cohort, we applied 10Hz transcranial alternating current stimulation (tACS), a method shown to entrain local oscillatory activity, to left M1 (lM1) and right cerebellum (rCB) during sequence learning. We observed a tendency for diminished learning following rCB tACS compared to sham, but not following lM1 tACS. Learning-related alpha power following rCB tACS was increased in left PMC, possibly reflecting increase in local inhibitory neural activity. Importantly, learning-specific alpha coherence between left PMC and right cerebellar lobule VIIb was enhanced following rCB tACS. These findings provide strong evidence for a causal role of alpha oscillations in controlling information transfer in a premotor-cerebellar loop during motor sequence learning. Our findings are consistent with a model in which sequence learning may be impaired by enhancing premotor cortical alpha oscillation via external modulation of cerebellar oscillations.
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Ritmo alfa/fisiología , Cerebelo/fisiología , Aprendizaje/fisiología , Corteza Motora/fisiología , Desempeño Psicomotor/fisiología , Estimulación Transcraneal de Corriente Directa/métodos , Adolescente , Adulto , Electroencefalografía/métodos , Femenino , Humanos , Masculino , Red Nerviosa/fisiología , Tiempo de Reacción/fisiología , Adulto JovenRESUMEN
BACKGROUND: Several monogenic causes for isolated dystonia have been identified, but they collectively account for only a small proportion of cases. Two genome-wide association studies have reported a few potential dystonia risk loci; but conclusions have been limited by small sample sizes, partial coverage of genetic variants, or poor reproducibility. OBJECTIVE: To identify robust genetic variants and loci in a large multicenter cervical dystonia cohort using a genome-wide approach. METHODS: We performed a genome-wide association study using cervical dystonia samples from the Dystonia Coalition. Logistic and linear regressions, including age, sex, and population structure as covariates, were employed to assess variant- and gene-based genetic associations with disease status and age at onset. We also performed a replication study for an identified genome-wide significant signal. RESULTS: After quality control, 919 cervical dystonia patients compared with 1491 controls of European ancestry were included in the analyses. We identified one genome-wide significant variant (rs2219975, chromosome 3, upstream of COL8A1, P-value 3.04 × 10-8 ). The association was not replicated in a newly genotyped sample of 473 cervical dystonia cases and 481 controls. Gene-based analysis identified DENND1A to be significantly associated with cervical dystonia (P-value 1.23 × 10-6 ). One low-frequency variant was associated with lower age-at-onset (16.4 ± 2.9 years, P-value = 3.07 × 10-8 , minor allele frequency = 0.01), located within the GABBR2 gene on chromosome 9 (rs147331823). CONCLUSION: The genetic underpinnings of cervical dystonia are complex and likely consist of multiple distinct variants of small effect sizes. Larger sample sizes may be needed to provide sufficient statistical power to address the presumably multi-genic etiology of cervical dystonia. © 2021 International Parkinson and Movement Disorder Society.
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Estudio de Asociación del Genoma Completo , Tortícolis , Proteínas Adaptadoras de Señalización del Receptor del Dominio de Muerte/genética , Frecuencia de los Genes , Predisposición Genética a la Enfermedad/genética , Factores de Intercambio de Guanina Nucleótido/genética , Humanos , Polimorfismo de Nucleótido Simple/genética , Reproducibilidad de los Resultados , Tortícolis/genéticaRESUMEN
Social interactions can be stressful, especially if they involve provocation or ambiguity. At the same time, such interactions necessitate social cognition. The question thus arises how stress affects social cognition and how personality attributes modulate this effect. The aim of the current study was to investigate the link between emotional reactivity, physical exercise, and social cognition under stress. As a measure of social cognition, we used spontaneous perspective taking, i.e., the degree to which participants represented the mental state of another agent. Studying young female participants, we investigated how physiological regulation, measured through resting heart-rate variability, is related to spontaneous social perspective taking under stress, and to predicted anger in an ambiguous social scenario. When controlling for resting heart rate, vagally mediated heart-rate variability was negatively correlated with the effect of stress on perspective taking, indicating that good physiological regulation supports social cognition under stress. Further, participants who reported to exercise at least once a week showed higher perspective taking under stress than less active participants. Finally, we found tentative evidence for participants who exercised regularly to show reduced predicted anger in response to an ambiguous provocation. Our findings suggest that good physiological regulation and regular physical exercise support social cognition under stress.
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Ira , Estrés Psicológico , Ira/fisiología , Cognición/fisiología , Ejercicio Físico , Femenino , Frecuencia Cardíaca/fisiología , Humanos , PersonalidadRESUMEN
Visuomotor adaptation (VMA) is a form of motor learning essential for performing day to day routines. Theoretical models and empirical evidence suggest a specific cortico-striato-cerebellar loop that mediates early and late learning in VMA. Here, we investigated dynamic changes in neural activity and connectivity when learning a novel visuomotor rotation using fMRI. We found that motor cortical regions, parietal cortex and cerebellum are recruited in the early phase of VMA, gradually reduce their activity as learning reaches plateau and rebound when the visuomotor rotation is removed. At this phase, dubbed de-adaptation, individual performance correlated with activity in motor and parietal cortex such that stronger activity was associated with better performance. Theory suggests that VMA is governed by the cortico-striato-cerebellar network during the early phase of learning and by the cortico-cerebellar loop at later stages. We tested this hypothesis using dynamic causal modelling and found distinct modulation of a cerebellar to dorsal premotor cortex (dPMC) loop. Specifically, the cerebellar to dPMC connection was modulated during adaptation, suggesting a release of inhibition and net excitatory effect of cerebellum on dPMC. The modulation of cerebellar to dPMC connection during de-adaptation was specifically related to behavioral learning parameter: stronger release of inhibition of the cerebellar to dPMC connection was associated with better de-adaptation. We interpret these findings to reflect dynamic interactions between representation of movement in cerebellum and visuomotor integration in dPMC.
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Adaptación Fisiológica/fisiología , Cerebelo/fisiología , Corteza Motora/fisiología , Desempeño Psicomotor/fisiología , Adulto , Cerebelo/diagnóstico por imagen , Femenino , Humanos , Aprendizaje/fisiología , Imagen por Resonancia Magnética , Masculino , Modelos Neurológicos , Actividad Motora/fisiología , Corteza Motora/diagnóstico por imagen , Vías Nerviosas/diagnóstico por imagen , Vías Nerviosas/fisiología , Adulto JovenRESUMEN
Non-invasive transcranial stimulation of cerebellum and primary motor cortex (M1) has been shown to enhance motor learning. However, the mechanisms by which stimulation improves learning remain largely unknown. Here, we sought to shed light on the neural correlates of transcranial direct current stimulation (tDCS) during motor learning by simultaneously recording functional magnetic resonance imaging (fMRI). We found that right cerebellar tDCS, but not left M1 tDCS, led to enhanced sequence learning in the serial reaction time task. Performance was also improved following cerebellar tDCS compared to sham in a sequence production task, reflecting superior training effects persisting into the post-training period. These behavioral effects were accompanied by increased learning-specific activity in right M1, left cerebellum lobule VI, left inferior frontal gyrus and right inferior parietal lobule during cerebellar tDCS compared to sham. Despite the lack of group-level changes comparing left M1 tDCS to sham, activity increase in right M1, supplementary motor area, and bilateral middle frontal cortex, under M1 tDCS, was associated with better sequence performance. This suggests that lack of group effects in M1 tDCS relate to inter-individual variability in learning-related activation patterns. We further investigated how tDCS modulates effective connectivity in the cortico-striato-cerebellar learning network. Using dynamic causal modelling, we found altered connectivity patterns during both M1 and cerebellar tDCS when compared to sham. Specifically, during cerebellar tDCS, negative modulation of a connection from putamen to cerebellum was decreased for sequence learning only, effectively leading to decreased inhibition of the cerebellum. These results show specific effects of cerebellar tDCS on functional activity and connectivity in the motor learning network and may facilitate the optimization of motor rehabilitation involving cerebellar non-invasive stimulation.
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Cerebelo/fisiología , Aprendizaje/fisiología , Corteza Motora/fisiología , Desempeño Psicomotor/fisiología , Putamen/fisiología , Estimulación Transcraneal de Corriente Directa , Adulto , Mapeo Encefálico , Femenino , Humanos , Imagen por Resonancia Magnética , Masculino , Persona de Mediana Edad , Vías Nerviosas/fisiología , Tiempo de Reacción , Adulto JovenRESUMEN
Borderline personality disorder (BPD) is characterized by instability of affect, emotion dysregulation, and interpersonal dysfunction. Especially shame and guilt, so-called self-conscious emotions, are of central clinical relevance to BPD. However, only few experimental studies have focused on shame or guilt in BPD and none investigated their neurobiological underpinnings. In the present functional magnetic resonance imaging study, we took a scenario-based approach to experimentally induce feelings of shame, guilt, and disgust with neutral scenarios as control condition. We included 19 women with BPD (age 26.4 ± 5.8 years; DSM-IV diagnosed; medicated) and 22 healthy female control subjects (age 26.4 ± 4.6 years; matched for age and verbal IQ). Compared to controls, women with BPD reported more intense feelings when being confronted with affective scenarios, especially higher levels of shame, guilt, and fear. We found increased amygdala reactivity in BPD compared to controls for shame and guilt, but not for disgust scenarios (p = 0.05 FWE corrected at the cluster level; p < 0.0001 cluster defining threshold). Exploratory analyses showed that this was caused by a diminished habituation in women with BPD relative to control participants. This effect was specific to guilt and shame scenarios as both groups showed amygdala habituation to disgust scenarios. Our work suggests that heightened shame and guilt experience in BPD is not related to increased amygdala activity per se, but rather to decreased habituation to self-conscious emotions. This provides an explanation for the inconsistencies in previous imaging work on amygdala involvement in BPD as well as the typically slow progress in the psychotherapy of dysfunctional self-conscious emotions in this patient group.
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Síntomas Afectivos/fisiopatología , Trastorno de Personalidad Limítrofe/fisiopatología , Culpa , Habituación Psicofisiológica/fisiología , Vergüenza , Adulto , Síntomas Afectivos/diagnóstico por imagen , Síntomas Afectivos/etiología , Trastorno de Personalidad Limítrofe/complicaciones , Trastorno de Personalidad Limítrofe/diagnóstico por imagen , Mapeo Encefálico , Asco , Miedo/fisiología , Femenino , Humanos , Imagen por Resonancia Magnética , Adulto JovenRESUMEN
Alcohol intoxication is implicated in approximately half of all violent crimes. Over the past several decades, numerous theories have been proposed to account for the influence of alcohol on aggression. Nearly all of these theories imply that altered functioning in the prefrontal cortex is a proximal cause. In the present functional magnetic resonance imaging (fMRI) experiment, 50 healthy young men consumed either a low dose of alcohol or a placebo and completed an aggression paradigm against provocative and nonprovocative opponents. Provocation did not affect neural responses. However, relative to sober participants, during acts of aggression, intoxicated participants showed decreased activity in the prefrontal cortex, caudate, and ventral striatum, but heightened activation in the hippocampus. Among intoxicated participants, but not among sober participants, aggressive behavior was positively correlated with activation in the medial and dorsolateral prefrontal cortex. These results support theories that posit a role for prefrontal cortical dysfunction as an important factor in intoxicated aggression.
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Encéfalo/efectos de los fármacos , Encéfalo/fisiología , Etanol/administración & dosificación , Adulto , Agresión , Mapeo Encefálico , Núcleo Caudado/efectos de los fármacos , Núcleo Caudado/fisiología , Toma de Decisiones/efectos de los fármacos , Hipocampo/efectos de los fármacos , Hipocampo/fisiología , Humanos , Imagen por Resonancia Magnética , Masculino , Persona de Mediana Edad , Corteza Prefrontal/efectos de los fármacos , Corteza Prefrontal/fisiología , Estriado Ventral/efectos de los fármacos , Estriado Ventral/fisiología , Adulto JovenRESUMEN
Cross-frequency coupling is suggested to serve transfer of information between wide-spread neuronal assemblies and has been shown to underlie many cognitive functions including learning and memory. In previous work, we found that alpha (8-13â¯Hz) - gamma (30-48â¯Hz) phase amplitude coupling (αγPAC) is decreased during sequence learning in bilateral frontal cortex and right parietal cortex. We interpreted this to reflect decreased demands for visuo-motor mapping once the sequence has been encoded. In the present study, we put this hypothesis to the test by adding a "simple" condition to the standard serial reaction time task (SRTT) with minimal needs for visuo-motor mapping. The standard SRTT in our paradigm entailed a perceptual sequence allowing for implicit learning of a sequence of colors with randomly assigned motor responses. Sequence learning in this case was thus not associated with reduced demands for visuo-motor mapping. Analysis of oscillatory power revealed a learning-related alpha decrease pointing to a stronger recruitment of occipito-parietal areas when encoding the perceptual sequence. Replicating our previous findings but in contrast to our hypothesis, αγPAC was decreased in sequence compared to random trials over right frontal and parietal cortex. It also tended to be smaller compared to trials requiring a simple motor sequence. We additionally analyzed αγPAC in resting-state data of a separate cohort. PAC in electrodes over right parietal cortex was significantly stronger compared to sequence trials and tended to be higher compared to simple and random trials of the SRTT data. We suggest that αγPAC in right parietal cortex reflects a "default-mode" brain state, which gets perturbed to allow for encoding of visual regularities into memory.
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Encéfalo/fisiología , Aprendizaje Seriado/fisiología , Transferencia de Experiencia en Psicología/fisiología , Adulto , Electroencefalografía , Femenino , Humanos , Masculino , Estimulación Luminosa , Desempeño Psicomotor/fisiología , Tiempo de Reacción/fisiología , Adulto JovenRESUMEN
Implicit measures of aggressiveness are able to circumvent response biases that plague self-reports, but it is unclear how they link to neural activation during aggressive interactions and to aggression-related endocrine function. Here, we tested whether an implicit attentional bias toward antisocial semantic information was associated with endogenous testosterone (T) and cortisol (C) levels, as well as with aggressive behavior and amygdala reactivity to angry faces in a separate competitive paradigm. On Day one, participants (39 healthy young women) completed an emotional word Stroop task in which they had to indicate the font color of antisocial, prosocial, or neutral words. On Day two, we measured subjects' brain activity during a competitive reaction time task in which the female opponent displayed angry or neutral facial expressions at the start of each trial and provoked participants with increasingly strong sound blasts. T and C were measured in saliva during a regular weekday as well as before and after scanning. We previously showed that aggression was associated with enhanced amygdala reactivity to angry faces in this sample. The present analyses revealed that subjects were slower to identify the font color of antisocial relative to neutral words, and that this attentional bias predicted higher aggression. T and C were uncorrelated with Stroop scores. Crucially, the relationship between implicit attention to antisocial words and aggression was mediated by amygdala reactivity to angry faces. Our data indicate that a tendency to dwell on implicit hostile cues reflects enhanced responsivity to overt anger displays.
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Agresión/fisiología , Amígdala del Cerebelo/diagnóstico por imagen , Ira/fisiología , Atención/fisiología , Señales (Psicología) , Expresión Facial , Percepción Social , Adulto , Agresión/psicología , Femenino , Humanos , Imagen por Resonancia Magnética , Tiempo de Reacción/fisiología , Semántica , Adulto JovenRESUMEN
Empathy is an essential ability for prosocial behavior. Previous imaging studies identified a number of brain regions implicated in affective and cognitive aspects of empathy. In this study, we investigated the neural correlates of empathy from a network perspective using graph theory and beta-series correlations. Two independent data sets were acquired using the same paradigm that elicited empathic responses to socio-affective stimuli. One data set was used to define the network nodes and modular structure, the other data set was used to investigate the effects of emotional versus neutral stimuli on network connectivity. Emotional relative to neutral stimuli increased connectivity between 74 nodes belonging to different networks. Most of these nodes belonged to an extended default mode network (eDMN). The other nodes belonged to a cognitive control network or visual networks. Within the eDMN, posterior STG/TPJ regions were identified as provincial hubs. The eDMN also showed stronger connectivity to the cognitive control network encompassing lateral PFC regions. Connector hubs between the two networks were posterior cingulate cortex and ventrolateral PFC. This stresses the advantage of a network approach as regions similarly modulated by task conditions can be dissociated into distinct networks and regions crucial for network integration can be identified.
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Afecto/fisiología , Red Nerviosa/fisiología , Medio Social , Adulto , Algoritmos , Mapeo Encefálico , Cognición/fisiología , Empatía/fisiología , Femenino , Humanos , Procesamiento de Imagen Asistido por Computador , Imagen por Resonancia Magnética , Masculino , Red Nerviosa/diagnóstico por imagen , Vías Nerviosas/diagnóstico por imagen , Vías Nerviosas/fisiología , Lóbulo Parietal/diagnóstico por imagen , Lóbulo Parietal/fisiología , Estimulación Luminosa , Corteza Prefrontal/diagnóstico por imagen , Corteza Prefrontal/fisiología , Lóbulo Temporal/diagnóstico por imagen , Lóbulo Temporal/fisiología , Adulto JovenRESUMEN
Implicit visuomotor sequence learning is important for our daily life, e.g., when writing or playing an instrument. Previous research identified a network of cortical regions that is relevant for motor sequence learning, namely primary motor cortex, premotor cortex, superior parietal cortex, and subcortical regions, including basal ganglia and cerebellum. Here, we investigated learning-related changes in oscillatory activity (theta, alpha and gamma power) and cross-frequency interactions (theta- and alpha-gamma phase-amplitude coupling) within cortical regions during sensorimotor memory formation. EEG was recorded from a large group of participants (n=73) performing the serial reaction time task (SRTT). Posterior parietal alpha power was larger early-on during sequence learning and smaller in later sessions. Alpha/low-gamma (8-13Hz and 30-48Hz) phase-amplitude coupling (PAC) was significantly smaller during sequence learning over right superior parietal cortex and frontal cortex. During the transition from sequential stimuli to random stimuli, participants made more errors, indicating that they still implicitly attempted to implement the learned motor sequence. At the same time, alpha/low-gamma phase-amplitude coupling was found to be smaller during the transition relative to later random trials. Our results show that learning and implementing a learned motor sequence reduces alpha/low-gamma PAC over parietal and frontal cortex. Fronto-parietal alpha/low-gamma PAC might be relevant for visuomotor mapping which becomes less relevant once the motor sequence has been encoded.
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Ritmo alfa/fisiología , Lóbulo Frontal/fisiología , Aprendizaje/fisiología , Lóbulo Parietal/fisiología , Desempeño Psicomotor/fisiología , Corteza Sensoriomotora/fisiología , Adolescente , Adulto , Mapeo Encefálico , Femenino , Humanos , Masculino , Destreza Motora/fisiología , Red Nerviosa/fisiología , Vías Nerviosas/fisiología , Tiempo de Reacción/fisiología , Adulto JovenRESUMEN
Changes in the environment require rapid modification or inhibition of ongoing behavior. We used the stop-signal paradigm and intracranial recordings to investigate response preparation, inhibition, and monitoring of task-relevant information. Electrocorticographic data were recorded in eight patients with electrodes covering frontal, temporal, and parietal cortex, and time-frequency analysis was used to examine power differences in the beta (13-30 Hz) and high-gamma bands (60-180 Hz). Over motor cortex, beta power decreased, and high-gamma power increased during motor preparation for both go trials (Go) and unsuccessful stops (US). For successful stops (SS), beta increased, and high-gamma was reduced, indexing the cancellation of the prepared response. In the middle frontal gyrus (MFG), stop signals elicited a transient high-gamma increase. The MFG response occurred before the estimated stop-signal reaction time but did not distinguish between SS and US trials, likely signaling attention to the salient stop stimulus. A postresponse high-gamma increase in MFG was stronger for US compared with SS and absent in Go, supporting a role in behavior monitoring. These results provide evidence for differential contributions of frontal subregions to response inhibition, including motor preparation and inhibitory control in motor cortex and cognitive control and action evaluation in lateral prefrontal cortex.
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Epilepsia Refractaria/fisiopatología , Corteza Motora/fisiología , Inhibición Neural , Adulto , Atención , Ritmo beta , Femenino , Ritmo Gamma , Humanos , Masculino , Corteza Motora/fisiopatología , Desempeño PsicomotorRESUMEN
Bilateral vestibular failure (BVF) is a severe chronic disorder of the labyrinth or the eighth cranial nerve characterized by unsteadiness of gait and disabling oscillopsia during head movements. According to animal data, vestibular input to the hippocampus is proposed to contribute to spatial memory and spatial navigation. Except for one seminal study showing the association of impaired spatial navigation and hippocampal atrophy, patient data in BVF are lacking. Therefore, we performed a voxel-wise comparison of the hippocampal gray matter volume (GMV) in a clinically representative sample of 27 patients with incomplete BVF and 29 age- and gender-matched healthy controls to test the hypothesis of hippocampal atrophy in BVF. Although the two groups did not generally differ in their hippocampal GMV, a reduction of GMV in the bilateral hippocampal CA3 region was significantly correlated with increased vestibulopathy-related clinical impairment. We propose that GMV reduction in the hippocampus of BVF patients is related to the severity of vestibular-induced disability which is in line with combined hippocampal atrophy and disorders of spatial navigation in complete vestibular deafferentation due to bilateral nerve section. Clinically, however, the most frequent etiologies of BVF cause incomplete lesions. Accordingly, hippocampus atrophy and deficits in spatial navigation occur possibly less frequently than previously suspected. Hum Brain Mapp 37:1998-2006, 2016. © 2016 Wiley Periodicals, Inc.
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Vestibulopatía Bilateral/patología , Sustancia Gris/patología , Hipocampo/patología , Anciano , Atrofia/patología , Vestibulopatía Bilateral/diagnóstico por imagen , Vestibulopatía Bilateral/fisiopatología , Estudios de Casos y Controles , Electroencefalografía , Potenciales Evocados/fisiología , Femenino , Sustancia Gris/diagnóstico por imagen , Humanos , Procesamiento de Imagen Asistido por Computador , Imagen por Resonancia Magnética , Masculino , Persona de Mediana Edad , Reflejo Vestibuloocular/fisiología , Análisis de Regresión , Índice de Severidad de la Enfermedad , Encuestas y CuestionariosRESUMEN
Altered neural processing of social signals such as angry facial expressions has been associated with increased aggressive behavior, but evidence for this relationship in healthy persons using ecologically valid experimental designs is lacking. We presented socially relevant videos of facial expressions in a functional magnetic resonance imaging (fMRI) version of the well-established Taylor Aggression Paradigm and investigated 41 healthy male participants, of whom 32 were included in the analysis. In each round of this competitive reaction time task, participants observed their opponent while he selected a punishment level for him, bearing either a neutral or angry facial expression. Afterward, participants in turn selected a punishment level for their opponent. Across participants, reactivity of the medial orbitofrontal cortex (OFC) to angry facial expressions was negatively related to aggressive behavior. Within participants and across trials, activity in the anterior cingulate cortex (ACC) was positively related to aggressive behavior specifically in response to angry expressions. Moreover, we found an effect of angry expressions on neural activity patterns during later stages of the task, demonstrating that the effect of angry expressions on neural reactivity is more than just a short-lived, stimulus-driven response. Our results underscore the importance of OFC and ACC for the shaping of socially adaptive responses to provocation.