Neuroscience 2005 Abstract
| Presentation Number: | 454.14 |
|---|---|
| Abstract Title: | A novel method for localizing electrode trajectories in the macaque brain using MRI. |
| Authors: |
Kalwani, R. M.*1
; Bloy, L.2
; Hulvershorn, J. W.3
; Elliot, M. A.2
; Gold, J. I.1
1Dept of Neuroscience, Univ. of Pennsylvania, Philadelphia, PA 2Dept of Radiology, Univ. of Pennsylvania, Philadelphia, PA 3Dept of Biochemistry and Biophysics, Univ. of Pennsylvania, Philadelphia, PA |
| Primary Theme and Topics |
Techniques in Neuroscience - Staining, Tracing, and Imaging Techniques |
| Secondary Theme and Topics | Techniques in Neuroscience<br />- Computation and Simulation |
| Session: |
454. Imaging by MRI and PET I Poster |
| Presentation Time: | Monday, November 14, 2005 9:00 AM-10:00 AM |
| Location: | Washington Convention Center - Hall A-C, Board # VV46 |
| Keywords: | stereotaxic, recording cylinder, ellipse, brain mapping |
Success of in vivo microelectrode placement is particularly challenging when targeted brain regions are below the cortical surface because stereotaxic locations can vary between individuals. In the past, post-mortem histology was the only technique available to verify the accuracy of electrode placement. More recently, magnetic resonance imaging (MRI) has become widely used but provides only a qualitative account of the relative locations of brain structures and recording cylinders. We have developed a novel technique using MRI to more quantitatively determine electrode trajectories relative to desired anatomical targets.
Surgically implanted recording cylinders are fitted with a 7 cm-long plastic tube filled with CuSO4-doped water to aid in the segmentation of the cylinder from brain matter in an MRI volume taken at 1.5T. For slices in which the image of a cylinder can be clearly distinguished from surrounding structures, the cylinder is fit to an ellipse. The mean major and minor axes of all such ellipses are computed to determine the cylinder boundary. The centers of the ellipses are fit to a line describing the center axis of the cylinder. These measurements are used to compute the interior projection of the cylinder through the brain. Phantom studies indicate that this virtual projection estimates the coverage of the recording cylinders with errors less than 5-7%, as measured by the overlap of estimated and actual cylinder trajectories. This error arises primary from a shift in the estimate of the center axis by ~1 mm over a depth of ~6 cm. We have used this technique in conjunction with Caret (Van Essen et al., 2001) and AFNI (Cox, 1996) brain mapping software to successfully localize several regions of the macaque brain, including the middle temporal area, the lateral intraparietal area and the frontal eye field.
Surgically implanted recording cylinders are fitted with a 7 cm-long plastic tube filled with CuSO4-doped water to aid in the segmentation of the cylinder from brain matter in an MRI volume taken at 1.5T. For slices in which the image of a cylinder can be clearly distinguished from surrounding structures, the cylinder is fit to an ellipse. The mean major and minor axes of all such ellipses are computed to determine the cylinder boundary. The centers of the ellipses are fit to a line describing the center axis of the cylinder. These measurements are used to compute the interior projection of the cylinder through the brain. Phantom studies indicate that this virtual projection estimates the coverage of the recording cylinders with errors less than 5-7%, as measured by the overlap of estimated and actual cylinder trajectories. This error arises primary from a shift in the estimate of the center axis by ~1 mm over a depth of ~6 cm. We have used this technique in conjunction with Caret (Van Essen et al., 2001) and AFNI (Cox, 1996) brain mapping software to successfully localize several regions of the macaque brain, including the middle temporal area, the lateral intraparietal area and the frontal eye field.
Supported by Supported by EY015260, the McKnight Foundation, the Burroughs-Wellcome Fund, and the Sloan Foundation.
Sample Citation:
[Authors]. [Abstract Title]. Program No. XXX.XX. 2005 Neuroscience Meeting Planner. Washington, DC: Society for Neuroscience, 2005. Online.
Copyright © 2005-2026 Society for Neuroscience; all rights reserved. Permission to republish any abstract or part of any abstract in any form must be obtained in writing by SfN office prior to publication.
