Exaggerated activity in the beta band (13-35 Hz) is a hallmark of basal ganglia signals in patients with Parkinson's disease (PD). Beta activity however is not constantly elevated, but comes in bursts. In previous work we showed that the longer beta bursts are maintained, the more the oscillatory synchronisation within the subthalamic nucleus (STN) increases, which is posited to limit the information coding capacity of local circuits. Accordingly, a higher incidence of longer bursts correlates positively with clinical impairment, while the opposite is true for short, more physiological bursts. Here, we test the hypothesis that beta bursts not only indicate local synchronisation within the STN, but also phasic coupling across the motor network and hence entail an even greater restriction of information coding capacity in patients with PD. Local field potentials from the subthalamic nucleus and EEG over the motor cortex area were recorded in nine PD patients after temporary lead externalization after surgery for deep brain stimulation and overnight withdrawal of levodopa. Beta bursts were defined as periods exceeding the 75th percentile of signal amplitude and the coupling between bursts was considered using two distinct measurements, first the % overlapping (%OVL) as a feature of the amplitude coupling and secondly the phase synchrony index (PSI) to measure the phase coupling between regions. %OVL between STN and cortex and between the left and the right STN was higher than expected between the regions than if they had been independent. Similarly, PSI was higher during bursts as opposed to non-bursts periods. In addition, %OVL was greater for long compared to short bursts. Our results support the hypothesis that beta bursts involve long-range coupling between structures in the basal ganglia-cortical network. The impact of this is greater during long as opposed to short duration beta bursts. Accordingly, we posit that episodes of simultaneously elevated coupling across multiple structures in the basal ganglia-cortical circuit further limit information coding capacity and may have further impact upon motor impairment.

Humans daily face social situations involving conflicts between competing moral decision. Despite a substantial amount of studies published over the past 10 years, the respective role of emotions and reason, their possible interaction, and their behavioural expression during moral evaluation remains an unresolved issue. A dualistic approach to moral evaluation proposes that the right dorsolateral prefrontal cortex (rDLPFc) controls emotional impulses. However, recent findings raise the possibility that the right DLPFc processes emotional information during moral decision making. We used repetitive transcranial magnetic stimulation (rTMS) to transiently disrupt rDLPFc activity before measuring decision making in the context of moral dilemmas. Results reveal an increase of the probability of utilitarian responses during objective evaluation of moral dilemmas in the rTMS group (compared to a SHAM one). This suggests that the right DLPFc function not only participates to a rational cognitive control process, but also integrates emotions generated by contextual information appraisal, which are decisive for response selection in moral judgements.