Intraoperative Mapping of the Anterior Nucleus of the Thalamus
Abstract number :
1.478
Submission category :
9. Surgery / 9A. Adult
Year :
2023
Submission ID :
1280
Source :
www.aesnet.org
Presentation date :
12/2/2023 12:00:00 AM
Published date :
Authors :
Presenting Author: David Satzer, MD – University of Colorado - Anschutz Medical Campus
Megan Ryan, MS – Neurosurgery – University of Colorado - Anschutz Medical Campus; Lesley Kaye, MD – Neurology – University of Colorado - Anschutz Medical Campus; Steven Ojemann, MD – Neurosurgery – University of Colorado - Anschutz Medical Campus; Daniel Kramer, MD – Neurosurgery – University of Colorado - Anschutz Medical Campus; John Thompson, PhD – Neurosurgery – University of Colorado - Anschutz Medical Campus
Rationale: Deep brain stimulation (DBS) of the anterior nucleus of the thalamus (ANT) is an effective therapy for drug-resistant focal epilepsy. Prior studies have suggested that the junction of the ANT and the mammillothalamic tract (mtt) is the optimal stimulation target. Electrophysiologic biomarkers to guide electrode placement and therapeutic programming remain elusive.
Methods: Microelectrode recording (MER) was performed in seven patients (fourteen hemispheres) during placement of ANT DBS electrodes under general anesthesia. Single-cell recordings and local field potentials (LFP) were measured from the microelectrode tip. MER sites were determined based upon co-registration of preoperative MRI, postoperative CT, and the Morel atlas of the thalamus. Single-unit bursting was characterized visually.
Results: ANT single-unit activity was characterized by regular bursting activity that disappeared upon mtt entry. Spectral analysis of intraoperative LFP revealed an alpha band (8-12 Hz) peak, the center and prominence of which was consistent between hemispheres but varied between patients. Overall, alpha power was highest at the ANT-mtt border and dorsal mtt. Maximal alpha power was seen within 3 mm of the ANT-mtt border in 7/11 hemispheres.
Conclusions: The border between ANT and mtt may be defined through intraoperative single-cell and LFP recordings under general anesthesia. Given that stimulation proximity to the ANT-mtt junction has been positively correlated with seizure reduction, alpha band oscillations originating from that location might serve as a useful biomarker for targeting and therapeutic programming. Further work is needed to explore the effects of seizures and stimulation on ANT-mtt alpha oscillations.
Funding: This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.
Surgery