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The mirror neuron system (MNS) becomes active during action execution and action observation, which is presumably reflected by reductions in mu (8–13 Hz) activity in the electroencephalogram over the sensorimotor cortex. The function of the MNS is still fiercely debated. The current study aimed to investigate a role of the MNS in anticipating others' actions by examining whether the MNS was activated – indexed by mu power suppression – prior to the onset of observed actions when the onset and type of action could be predicted on the basis of environmental cues. Young adults performed and observed cued grasping and placing actions in a card game in a real-life setting, while the predictability of the observed actions was manipulated using rules. Significant mu suppression, relative to within-trial baseline activity, was found both prior to and during executed actions, but also during action observation, and, crucially, prior to observed actions provided they were predictable. No anticipatory mu reductions were found prior to unpredictable observed actions. These results suggest top-down modulation of MNS activity by conceptual knowledge. This is the first study to demonstrate mu suppression prior to action onset – possibly reflecting MNS anticipatory activity – by explicitly manipulating predictability. [ABSTRACT FROM AUTHOR]

While much progress has been made in how brain organization supports language function, the language network's ability to adapt to immediate disturbances by means of reorganization remains unclear. The aim of this study was to examine acute reorganizational changes in brain activity related to conceptual and lexical retrieval in unimpaired language production following transient disruption of the left middle temporal gyrus (MTG). In a randomized single‐blind within‐subject experiment, we recorded the electroencephalogram from 16 healthy participants during a context‐driven picture‐naming task. Prior to the task, the left MTG was perturbed with real continuous theta‐burst stimulation (cTBS) or sham stimulation. During the task, participants read lead‐in sentences creating a constraining (e.g., "The farmer milks the") or nonconstraining context (e.g., "The farmer buys the"). The last word was shown as a picture that participants had to name (e.g., "cow"). Replicating behavioral studies, participants were overall faster in naming pictures following a constraining relative to a nonconstraining context, but this effect did not differ between real and sham cTBS. In contrast, real cTBS increased overall error rates compared to sham cTBS. In line with previous studies, we observed a decrease in alpha‐beta (8–24 Hz) oscillatory power for constraining relative to nonconstraining contexts over left temporal–parietal cortex after participants received sham cTBS. However, following real cTBS, this decrease extended toward left prefrontal regions associated with both domain‐general and domain‐specific control mechanisms. Our findings provide evidence that immediately after perturbing the left MTG, the lexical‐semantic network is able to quickly reconfigure, also recruiting domain‐general regions. [ABSTRACT FROM AUTHOR]

High frequency repetitive Transcranial Magnetic Stimulation (rTMS) over the left dorsolateral prefrontal cortex (DLPFC) has been found to alleviate depressive symptoms. However, the mechanisms driving these effects are still poorly understood. In the current study, we tested the idea that this intervention protects against negative mood shifts following emotional provocation. We furthermore explored changes in EEG activity (frontal alpha asymmetry) and effects on attentional processing (emotional Stroop). To this end, 23 healthy individuals participated in two sessions separated by one week, whereby they once received 15min of 10Hz rTMS stimulation (1500 pulses) at 110% of the individual motor threshold, and once sham stimulation. Then, negative mood was induced using sad movie clips. The results revealed a significantly stronger mood decline following rTMS compared to sham stimulation. No changes were observed in frontal alpha asymmetry and attentional processing. Our findings are at odds with the view that high frequency rTMS over the left DLPFC directly protects against the induction of negative mood, but rather suggest that it enhances the effects of emotional provocation. Possibly, in healthy young individuals, this stimulation protocol heightens susceptibility to mood induction procedures in general. [ABSTRACT FROM AUTHOR]

Objective: Paired associative stimulation (PAS) has been used to study normal and abnormal cortical plasticity. However, a normative review of PAS effects has not been provided so far. To this end, the magnitude and time course of PAS protocols was systematically evaluated here. Methods: A literature search in PubMed using the search term paired associative stimulation was conducted. Main inclusion criteria were that experiments were conducted in primary motor cortex of healthy volunteers without motor training before intervention and motor evoked potentials as primary outcome measure. This search yielded in total 104 experiments, which were analyzed to examine the potentiating (PASLTP) and depressing effects of PAS (PASLTD) on cortical excitability levels in healthy volunteers. Results: PASLTP induces reliable and stable potentiating effects (maximum ± standard error 38.5 ± 3.3%) on cortical excitability levels up to 90 min. PASLTP was most effective when applied at frequencies of 0.05 and 0.2 Hz. Analyses of the PASLTD studies demonstrated reliable and stable depression of cortical excitability levels up to 120 min (maximum ± standard error -23.0 ± 1.9%). Conclusions: PAS significantly modulates cortical excitability. The potentiating effects of PASLTP are stronger than the depressing effects for PASLTD. [ABSTRACT FROM AUTHOR]

This review discusses neurobiological studies of oppositional defiant disorder and conduct disorder within the conceptual framework of three interrelated mental domains: punishment processing, reward processing, and cognitive control. First, impaired fear conditioning, reduced cortisol reactivity to stress, amygdala hyporeactivity to negative stimuli, and altered serotonin and noradrenaline neurotransmission suggest low punishment sensitivity, which may compromise the ability of children and adolescents to make associations between inappropriate behaviors and forthcoming punishments. Second, sympathetic nervous system hyporeactivity to incentives, low basal heart rate associated with sensation seeking, orbitofrontal cortex hyporeactiviy to reward, and altered dopamine functioning suggest a hyposensitivity to reward. The associated unpleasant emotional state may make children and adolescents prone to sensation-seeking behavior such as rule breaking, delinquency, and substance abuse. Third, impairments in executive functions, especially when motivational factors are involved, as well as structural deficits and impaired functioning of the paralimbic system encompassing the orbitofrontal and cingulate cortex, suggest impaired cognitive control over emotional behavior. In the discussion we argue that more insight into the neurobiology of oppositional defiance disorder and conduct disorder may be obtained by studying these disorders separately and by paying attention to the heterogeneity of symptoms within each disorder. [ABSTRACT FROM AUTHOR]

Several lines of evidence point towards the involvement of the cerebellum in reactive aggression. In addition to the posterior cerebellar hemisphere, the vermis has been suggested to play a prominent role in impulse regulation. In the present study, we set out to further examine the relationships between cerebellar grey matter volumes, aggression, and impulsivity in 201 healthy volunteers. 3 T structural magnetic resonance imaging scans were acquired to investigate grey matter volumes of the cerebellar vermis and the anterior and posterior lobules. Aggression was assessed with the Buss–Perry Aggression Questionnaire and impulsivity was measured with the Barratt Impulsiveness Scale-11. Results showed that impulsivity was positively associated with grey matter volumes of the cerebellar vermis and inversely correlated with grey matter volumes of the right posterior lobule. In addition, smaller volumes of the right posterior lobules were associated with higher physical aggression. Exploratory analyses indicated that for the right hemisphere, this association was driven by grey matter volumes of lobules VIIb and VIIIa. Our findings provide correlational evidence in healthy volunteers for the involvement of the cerebellar vermis and posterior lobules in a cortico-limbic-cerebellar circuit of aggression. [ABSTRACT FROM AUTHOR]

The aim of this treatment study was to evaluate the therapeutic effects of repetitive transcranial magnetic stimulation (rTMS) over the right parietal cortex in depression. In a double-blind, sham-controlled design ten consecutive sessions of 2 Hz rTMS (inter-pulse interval 0.5 s) at 90% motor threshold to the right parietal cortex (2400 pulses per session) were applied to 34 patients with the primary diagnosis of DSM-IV depression and a score of ⩾15 on the 17-item Hamilton Rating Scale for Depression (HAMD). The primary outcome measures were the percentage change from baseline on the 17-item HAMD scores after ten sessions, and the percentage of clinical (defined as ⩾50% reduction in HAMD score) and partial clinical (defined as ⩾30% reduction in HAMD score) responders. Reduction of HAMD scores in the real rTMS treatment (meanreal±S.D.,-x19.9±32.5%) was not statistically different from the sham rTMS treatment (meansham±S.D., x5.6±28.4 %), and the number of clinical responders did not differ between treatments. However, a significant greater number of partial clinical responders were observed in the real (43.8%) compared to the sham rTMS treatment (6.3%). This study provides the first evidence showing that 2 Hz rTMS over the right parietal cortex may have antidepressant properties, and warrants further research. [ABSTRACT FROM AUTHOR]