There is a wealth of data suggesting that behavioural events are reflected in the basal ganglia through phasic changes in the discharge of individual neurones. Here we investigate whether events are also reflected in momentary changes in the degree of synchronization between neuronal elements. We simultaneously recorded local potentials (LPs) from the subthalamic nucleus (STN) and/or ipsilateral globus pallidus interna (GPi) or scalp EEG during voluntary movements of a hand-held joystick in six awake patients following neurosurgery for Parkinson's disease. Without medication the power within the STN and the coherence between the STN and the GPi were dominated by activity with a frequency of <30 Hz. This coupling was attenuated by movement. In the presence of exogenous dopaminergic stimulation, power within the STN and coherence between the STN and the GPi was dominated by activity at 70-85 Hz, which increased with movement. The movement-related changes in coherence between the STN and EEG showed a similar pattern of pharmacological dependence, as seen subcortically. Movement-related frequency-specific changes in synchronization occur in the basal ganglia and extend to involve subcortico-cortical motor loops. The dynamic organization of activities in the frequency domain might provide a means for temporal co-ordination within and across different processing streams in the basal ganglia. This organization is critically dependent on the level of dopaminergic activity.

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Measurements taken downstream of freeway/on-ramp merges have verified that discharge flow diminishes when a merge becomes an active bottleneck. We show that metering the on-ramp can recover the higher discharge flow and thereby increase merge capacity. Detailed observations collected using video revealed that the outflow drop following activation was triggered by a queue that formed near the merge in the freeway shoulder lane and then spread laterally, as drivers changed lanes to maneuver around slow traffic. Once restrictive metering mitigated this shoulder lane queue, high outflows often returned to the median lane. Merge outflow could be increased to levels measured prior to the bottleneck activation by then relaxing the metering rate so that inflows from the on-ramp increased. Although outflows recovered in this fashion were unstable and never persisted for periods greater than 13 mins, the findings are the first real evidence that ramp metering can favorably affect the capacity of an isolated merge. The findings point to control strategies that might stabilize outflow and increase merge capacity even more.

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