scholarly journals Deep Brain Stimulation Does Not Silence Neurons in Subthalamic Nucleus in Parkinson's Patients

2010 ◽  
Vol 103 (2) ◽  
pp. 962-967 ◽  
Author(s):  
Jonathan D. Carlson ◽  
Daniel R. Cleary ◽  
Justin S. Cetas ◽  
Mary M. Heinricher ◽  
Kim J. Burchiel

Two broad hypotheses have been advanced to explain the clinical efficacy of deep brain stimulation (DBS) in the subthalamic nucleus (STN) for treatment of Parkinson's disease. One is that stimulation inactivates STN neurons, producing a functional lesion. The other is that electrical stimulation activates the STN output, thus “jamming” pathological activity in basal ganglia-corticothalamic circuits. Evidence consistent with both concepts has been adduced from modeling and animal studies, as well as from recordings in patients. However, the stimulation parameters used in many recording studies have not been well matched to those used clinically. In this study, we recorded STN activity in patients with Parkinson's disease during stimulation delivered through a clinical DBS electrode using standard therapeutic stimulus parameters. A microelectrode was used to record the firing of a single STN neuron during DBS (3–5 V, 80–200 Hz, 90- to 200-μs pulses; 33 neurons/11 patients). Firing rate was unchanged during the stimulus trains, and the recorded neurons did not show prolonged (s) changes in firing rate on termination of the stimulation. However, a brief (∼1 ms), short-latency (6 ms) postpulse inhibition was seen in 10 of 14 neurons analyzed. A subset of neurons displayed altered firing patterns, with a predominant shift toward random firing. These data do not support the idea that DBS inactivates the STN and are instead more consistent with the hypothesis that this stimulation provides a null signal to basal ganglia-corticothalamic circuitry that has been altered as part of Parkinson's disease.

Author(s):  
Ashesh A. Thaker ◽  
Kartik M. Reddy ◽  
John A. Thompson ◽  
Pamela David Gerecht ◽  
Mark S. Brown ◽  
...  

<b><i>Introduction:</i></b> Deep brain stimulation of the zona incerta is effective at treating tremor and other forms of parkinsonism. However, the structure is not well visualized with standard MRI protocols making direct surgical targeting unfeasible and contributing to inconsistent clinical outcomes. In this study, we applied coronal gradient echo MRI to directly visualize the rostral zona incerta in Parkinson’s disease patients to improve targeting for deep brain stimulation. <b><i>Methods:</i></b> We conducted a prospective study to optimize and evaluate an MRI sequence to visualize the rostral zona incerta in patients with Parkinson’s disease (<i>n</i> = 31) and other movement disorders (<i>n</i> = 13). We performed a contrast-to-noise ratio analysis of specific regions of interest to quantitatively assess visual discrimination of relevant deep brain structures in the optimized MRI sequence. Regions of interest were independently assessed by 2 neuroradiologists, and interrater reliability was assessed. <b><i>Results:</i></b> Rostral zona incerta and subthalamic nucleus were well delineated in our 5.5-min MRI sequence, indicated by excellent interrater agreement between neuroradiologists for region-of-interest measurements (&#x3e;0.90 intraclass coefficient). Mean contrast-to-noise ratio was high for both rostral zona incerta (6.39 ± 3.37) and subthalamic nucleus (17.27 ± 5.61) relative to adjacent white matter. There was no significant difference between mean signal intensities or contrast-to-noise ratio for Parkinson’s and non-Parkinson’s patients for either structure. <b><i>Discussion/Conclusion:</i></b> Our optimized coronal gradient echo MRI sequence delineates subcortical structures relevant to traditional and novel deep brain stimulation targets, including the zona incerta, with high contrast-to-noise. Future studies will prospectively apply this sequence to surgical planning and postimplantation outcomes.


2019 ◽  
Vol 9 (3) ◽  
pp. 51 ◽  
Author(s):  
Rens Verhagen ◽  
Lo Bour ◽  
Vincent Odekerken ◽  
Pepijn van den Munckhof ◽  
P. Schuurman ◽  
...  

Motor improvement after deep brain stimulation (DBS) in the subthalamic nucleus (STN) may vary substantially between Parkinson’s disease (PD) patients. Research into the relation between improvement and active contact location requires a correction for anatomical variation. We studied the relation between active contact location relative to the neurophysiological STN, estimated by the intraoperative microelectrode recordings (MER-based STN), and contralateral motor improvement after one year. A generic STN shape was transformed to fit onto the stereotactically defined MER sites. The location of 43 electrodes (26 patients), derived from MRI-fused CT images, was expressed relative to this patient-specific MER-based STN. Using regression analyses, the relation between contact location and motor improvement was studied. The regression model that predicts motor improvement based on levodopa effect alone was significantly improved by adding the one-year active contact coordinates (R2 change = 0.176, p = 0.014). In the combined prediction model (adjusted R2 = 0.389, p < 0.001), the largest contribution was made by the mediolateral location of the active contact (standardized beta = 0.490, p = 0.002). With the MER-based STN as a reference, we were able to find a significant relation between active contact location and motor improvement. MER-based STN modeling can be used to complement imaging-based STN models in the application of DBS.


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