Neuroscience 2005 Abstract
| Presentation Number: | 706.5 |
|---|---|
| Abstract Title: | Brain mechanisms underlying electroacupuncture-induced analgesia: a functional MRI study. |
| Authors: |
Feldman, S. C.*1
; Liu, W.1
; Xu, T.1
; Cook, D.1
; Komisaruk, B.2
1Dept Radiol, New Jersey Med. School, Newark, NJ 2NJ, 185 S Orange Ave, 07103, |
| Primary Theme and Topics |
Sensory and Motor Systems - Pain -- Pain imaging and perception |
| Session: |
706. Pain Imaging and Modulation Slide |
| Presentation Time: | Tuesday, November 15, 2005 2:00 PM-2:15 PM |
| Location: | Washington Convention Center - Room 201 |
| Keywords: | pain, thalamus and limbic system, activation volume changes, humans |
We previously reported that manual acupuncuture results in biphasic activation of specific CNS regions. In the present study we employed a continuous 25 min Electro-Acupuncture (EA) stimulation to examine the brain responses associated with attaining acupuncture-induced analgesia.
Ten subjects were studied,all signed our institution’s human subject protection (IRB) form. The study consisted of three conditions: EA acupuncture of two analgesia-related acupoints (LI-4, St-36), EA of a sham acupoint, and no stimulation. EA (2Hz) was applied for 25 minutes. Analgesia was assessed by determining a heat pain threshold for each subject before and after the test situations. Brain imaging was done on a Siemens 3T head only (Allegra) scanner with a standard bird-cage coil. Images were taken every 5 minutes. Data was analyzed using SPM99 and AFNI.We measured changes in activation volume for the 25 min and at each 5min step. FFT was used to determine changes in oscillation frequency and/or amplitude. The following regions showed increased activity: SM 1 and 2, anterior cingulate, insula, limbic structures, basal ganglia and thalamus. Activation volume in these areas was biphasic, i.e., the volumes increased to a maximum at 20 minutes, then decreased significantly despite continued stimulation.
A selective low frequency enhancement at 0.01 Hz was found in all the subjects. The maximal amplitude appeared at 15-20 min after EA onset. After acupuncture seven subjects had an increased pain threshold of 2.1 degree C; one subject had a decreased pain temperature threshold. The imaging correlates of analgesia showed decreased activation in all of the areas studied. The increased pain threshold temperature is suggestive of analgesia.The strong correlation between the maximal activated volume and the maximal amplitude of the oscillation may shed some light on the neuronal mechanisms underlying the attainment of analgesia. The enhanced low frequency oscillation may provide the reason for the reduced activity.
Ten subjects were studied,all signed our institution’s human subject protection (IRB) form. The study consisted of three conditions: EA acupuncture of two analgesia-related acupoints (LI-4, St-36), EA of a sham acupoint, and no stimulation. EA (2Hz) was applied for 25 minutes. Analgesia was assessed by determining a heat pain threshold for each subject before and after the test situations. Brain imaging was done on a Siemens 3T head only (Allegra) scanner with a standard bird-cage coil. Images were taken every 5 minutes. Data was analyzed using SPM99 and AFNI.We measured changes in activation volume for the 25 min and at each 5min step. FFT was used to determine changes in oscillation frequency and/or amplitude. The following regions showed increased activity: SM 1 and 2, anterior cingulate, insula, limbic structures, basal ganglia and thalamus. Activation volume in these areas was biphasic, i.e., the volumes increased to a maximum at 20 minutes, then decreased significantly despite continued stimulation.
A selective low frequency enhancement at 0.01 Hz was found in all the subjects. The maximal amplitude appeared at 15-20 min after EA onset. After acupuncture seven subjects had an increased pain threshold of 2.1 degree C; one subject had a decreased pain temperature threshold. The imaging correlates of analgesia showed decreased activation in all of the areas studied. The increased pain threshold temperature is suggestive of analgesia.The strong correlation between the maximal activated volume and the maximal amplitude of the oscillation may shed some light on the neuronal mechanisms underlying the attainment of analgesia. The enhanced low frequency oscillation may provide the reason for the reduced activity.
Sample Citation:
[Authors]. [Abstract Title]. Program No. XXX.XX. 2005 Neuroscience Meeting Planner. Washington, DC: Society for Neuroscience, 2005. Online.
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