DBS is a surgically implanted device to deliver electrical pulses to inner brain structures involved in movement. Parkinson's disease patients who receive treatment, symptoms of movement, tremor and rigidity diminish when the device is activated, and quickly return if the device is turned off.
Despite the great success of DBS, some significant problems remain. A minority of patients never obtains the full benefit their physicians expect, some patients respond differently to DBS than others.
Researchers placed electrodes under the skulls of patients implanted with the DBS device. The activity of the motor cortex was recorded focusing on the synchronization of the signals throughout the brain region. The recordings showed excessive synchronization of activity rhythms in Parkinson's patients.
When DBS was placed in the subthalamic nucleus, when the stimulation reached the motor cortex, synchronization rapidly diminished, as though the neurons have decoupled themselves and are acting independently.