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Identification of the target neuronal elements in electrical deep brain stimulation
J Holsheimer1, H Demeulemeester, B Nuttin
1Institute for Biomedical Technology, University of Twente, PO Box 217, NL-7500 AE Enschede, The Netherlands. j.holsheimer@el.utwente.nl
The European Journal of Neuroscience
|December 21, 2000
Summary
Deep-brain stimulation likely targets large myelinated axons, not cell bodies, in Parkinson
Area of Science:
- Neuroscience
- Neurosurgery
- Biomedical Engineering
Background:
- Deep-brain stimulation (DBS) is a therapeutic intervention for neurological disorders such as Parkinson's disease and essential tremor.
- Identifying the precise neuronal elements targeted by DBS is crucial for optimizing stimulation parameters and therapeutic outcomes.
- Neuronal elements, including large myelinated axons, small axons, and cell bodies/dendrites, exhibit distinct electrical properties, characterized by their strength-duration time constants (τsd).
Purpose of the Study:
- To determine the primary neuronal targets of electrical deep-brain stimulation in the thalamus and internal pallidum.
- To differentiate between axonal and cellular targets by analyzing strength-duration properties during tremor suppression.
Main Methods:
- Strength-duration data were collected from patients with Parkinson's disease or essential tremor undergoing DBS.
- Threshold voltages for tremor elimination were measured at various pulsewidths with high-frequency stimulation (130 Hz).
- The strength-duration time constant (τsd) was calculated using Weiss's linear approximation, with corrections for electrode polarization and amplitude resolution errors.
Main Results:
- Calculated mean τsd values were approximately 64.6 µs (thalamus) and 75.3 µs (internal pallidum) before corrections.
- After accounting for systematic errors, corrected mean τsd estimates were 129 µs (thalamus) and 151 µs (internal pallidum).
- These corrected τsd values align with the known properties of large myelinated axons (approx. 30–200 µs).
Conclusions:
- The findings strongly suggest that large myelinated axons are the primary neuronal targets activated during therapeutic DBS in the ventral intermediate thalamic nucleus and internal pallidum.
- This understanding aids in refining DBS electrode design and stimulation strategies for improved efficacy in movement disorder treatment.