Dual microelectrode technique for deep brain stereotactic surgery in humans

Department of Physiology, University of Toronto, Toronto, Canada.
Neurosurgery (Impact Factor: 3.62). 04/2007; 60(4 Suppl 2):277-83; discussion 283-4. DOI: 10.1227/01.NEU.0000255389.85161.03
Source: PubMed


To improve functional stereotactic microelectrode localization of small deep brain structures by developing and evaluating a recording system with two closely separated independently controlled microelectrodes.
Data were obtained from 52 patients using this dual microelectrode technique and 38 patients using the standard single microelectrode technique for subthalamic nucleus localization in patients with Parkinson's disease.
There was a decrease in the incidence of noncontributory trajectories, defined as a single penetration made by the pair of closely spaced parallel microelectrodes, owing to microelectrode failure (from 7.2% to <1%), an improved localization and verification of nuclear borders, and a significant decrease in the number of trajectories used to localize the subthalamic nucleus from a median of three to two per initial operative side (P < 0.001). The technique also provides the novel opportunity to examine population activity by correlating the discharge between two closely spaced simultaneously recorded neurons and can be used to monitor the electrophysiological effects of local electrical stimulation or microinjections of pharmacological agents.
Our experience indicates that the use of two closely spaced microelectrodes improves the utility of microelectrode localization in minimally invasive functional neurosurgery.

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    • "A tungsten microelectrode was used for both extracellular stimulation and recording (10 Hz–5 kHz bandpass filtered, 1000–5000 gain; Guideline 3000 system, Axon Instruments, Union City, CA) in each subject (see [13] for further details). The microelectrode passed through the thalamus as it was driven toward the STN. "
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    • "Another important anatomical landmark was the internal capsule that could be identified by stimulation-evoked tetanic contractions of contralateral muscles. Monopolar extracellular recordings of neuronal firing and LFPs were obtained simultaneously using two independently driven tungsten microelectrodes (about 25 lm tip length, axes 600 lm apart, $0.2-MX impedance at 1 kHz) as described previously (Levy et al., 2007). Recordings were amplified 5000–10,000 times and filtered at 10–5000 Hz (analog Butterworth filters: high-pass, one pole; low-pass, two poles; at 5 Hz amplitude was decreased by roughly 50%) using two Guideline System GS3000 (Axon Instruments , Union City, CA) amplifiers. "
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