There was also a significant shift in the population of VA/VLo neurons that were inhibited during STN DBS, whereas VPLo neurons tended to be activated. Burst activity was reduced in VA/VLo, but was not significantly changed in VPLo. Neurons in both VA/VLo and VPLo tended to become more periodic and regular with a shift in oscillatory activity from low to high frequencies. Stimulation parameters that produced improvement in rigidity and bradykinesia resulted in changes in the pattern and power of oscillatory activity of neuronal activity that were similar in both regions of the motor thalamus. Here we extend our observations to neurons in the pallidal and cerebellar receiving areas of the motor thalamus during STN DBS. We previously reported STN stimulation increased the rate and produced a more regular and periodic pattern of neuronal activity in the internal segment of the globus pallidus (GPi). The mechanism by which STN DBS elicits its beneficial effect, however, remains unclear.
Intraoperative microelectrode recordings confirmed these coordinates in all cases from the first microelectrode pass, thereby eliminating prolonged intraoperative electrophysiological STN searching and tissue disruption that may occur from multiple passes.ģT MR imaging appears to be an excellent tool for reliable and accurate direct visualization of the human STN, necessary for precise surgical targeting.Deep brain stimulation (DBS) in the subthalamic nucleus (STN) is an effective tool for the treatment of advanced Parkinson's disease. These coordinates are used for surgical targeting.Īt 3T, the STN was visualized as a small, hypointense, almond-shaped structure in 3 planes located immediately lateral to the anterior edge of the red nucleus, medial to the internal capsule, about 5 mm inferior, 1-2 mm posterior, and 9-12 mm lateral to the midcommissural point.
The STN is identified in all 3 planes by cross-referencing in a 3-plane viewer. With the patient positioned within a standard Leksell type G stereotactic frame localizer, rapidly acquired scout images are used to prescribe volumes of contiguous high-resolution T2-weighted fast spin-echo images in the axial, sagittal, and coronal planes through the midbrain and basal ganglia. We performed preoperative stereotactic MR imaging at 3T to visualize the STN in 13 patients undergoing deep-brain stimulation for PD. The STN is also difficult to visualize directly by using MR imaging at 1.5 T. CT imaging is dependent on atlas coordinates, because the STN is not visualized. A combination of anatomic imaging with a stereotactic frame, atlas coordinates, and intraoperative neurophysiology is currently considered the most reliable approach for STN targeting. Although procedural details are well established, targeting STN remains problematic because of its variable location and relatively small size (20-30 mm(3)). Electrical stimulation of the subthalamic nucleus (STN) is an accepted treatment for advanced Parkinson disease (PD).