The Effect of General Anesthesia on Acupuncture: A Functional MRI Study
We performed a study to examine brain activity as assessed by functional-MRI when acupuncture is administered to awake volunteers as compared to acupuncture administered to volunteers under general anesthesia. Healthy, acupuncture-naive volunteers were recruited for this cross-over study. Volunteers underwent two experimental sessions that included a sequence of 4-20 seconds of on and off manual acupuncture stimulation for a period of 3 minutes while awake and while under propofol general anesthesia. The acupuncture intervention was performed at left stomach 36. General anesthesia was induced and maintained with propofol. BOLD signal images were obtained in a 1.5 T MRI scanner in both experimental conditions. The primary single subject analysis for each study utilized a GLM to examine the response to the stimulus, and a spatially varying autoregressive model for the temporal errors. f-MRI imaging obtained during acupuncture stimulation in awake volunteers revealed: (1) Activation foci at bilateral primary and secondary somatosensory cortices, hypothalamus, contralateral substantia nigra, nucleus accumbens, bilateral hippocampal formations, and bilateral superior colliculi; (2) Deactivations at bilateral posterior lobes of cerebellum and contralateral posterior temple lobe. In contrast, f-MRI imaging obtained during acupuncture stimulation in volunteers under general anesthesia revealed: (1) Activation foci at the limbic orbitofrontal cortex, ipsilateral putamen, contralateral temple lobe and bilateral primary visual cortices; (2) Deactivation at the ipsilateral primary and secondary somatosensory cortices. Statistical analysis revealed significant differences at the following areas: ipsilateral primary and secondary somatosensory cortices, hypothalamus, posterior lateral thalamus, and contralateral head of caudate (p<0.005). We found significant differences in brain f-MRI images when comparing acupuncture while awake to acupuncture given under propofol general anesthesia.
School Location:USA - Connecticut
Source Type:Master's Thesis
Keywords:acupuncture mri anesthesia brain activity
Date of Publication:11/15/2006