Neuroscience 2005 Abstract
| Presentation Number: | 456.5 |
|---|---|
| Abstract Title: | Comparison of neural activity in the rat spinal cord using functional magnetic resonance imaging (fMRI) and field potentials during noxious electrical stimulation of the hind paw. |
| Authors: |
Lawrence, J.*1
; Gardiner, P. F.1
; Gardiner, K. R.1
; Malisza, K. L.1,2
1Dept Physiol, Univ. of Manitoba, Winnipeg, Canada 2MB, 4th Floor, Basic Med Sci Bldg, R3G 3J7, |
| Primary Theme and Topics |
Techniques in Neuroscience - Staining, Tracing, and Imaging Techniques |
| Session: |
456. Imaging by MRI and PET II Poster |
| Presentation Time: | Monday, November 14, 2005 8:00 AM-9:00 AM |
| Location: | Washington Convention Center - Hall A-C, Board # VV86 |
| Keywords: | FUNCTIONAL MRI, SPINAL CORD, ELECTROPHYSIOLOGY |
Functional MRI is a non-invasive technique that indirectly detects areas of neuronal activity by observing local changes in blood oxygen. Until recently fMRI has been used only for brain imaging, however, it has since been applied to the spinal cord (spinal fMRI). The relationship between areas of fMRI activity and areas of neuronal activity must be verified by comparison with gold standards in order for spinal fMRI to become more widely accepted. In the present study we compare areas of fMRI activity with areas of extracellular field potentials during noxious electrical stimulation of the hind paw in rats. Halothane-anesthetized rats were placed supine on a quadrature surface coil tuned and matched to 300 MHz. Six, 2 mm thick slices were centred on the vertebra and intervertebral discs between T12 and L1. Three functional imaging experiments on each animal were performed using electrical stimulation (~ 7 mA) delivered by two silver needle electrodes inserted subcutaneously in the dorsal surface of the right hind paw. In the same rats, electrophysiology studies were then performed in which the third to fifth lumbar spinal cord segments were exposed and extracellular recordings were taken in the gray matter on both sides using a 2-MΩ tungsten electrode. Recordings were taken during rest and stimulation every 150 µm to a depth of 1800 µm, at several sites spanning these segments. The greatest amount of fMRI activity was observed at the T13 vertebra. Peak negative extracellular potentials were also observed at this level corresponding to the L4 spinal cord segment. The comparison of areas of field potentials with areas of fMRI activity confirm that spinal fMRI can be used to detected areas of neuronal activity in the spinal cord.
Sample Citation:
[Authors]. [Abstract Title]. Program No. XXX.XX. 2005 Neuroscience Meeting Planner. Washington, DC: Society for Neuroscience, 2005. Online.
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