Activation of the hypothalamus characterizes the acupuncture stimulation at the analgesic point in human: a positron emission tomography study

We performed a positron emission tomography study, using regional cerebral blood flow as the index of brain activity, to address the specificity of br ain activation pattern by acupuncture stimulation of short duration at the classical analgesic point. Needling manipulation at 2 Hz was performed at a classical point of prominent analgesic efficacy (Li 4, Heku) and a near-by non-classical/non-analgesic point, respectively, in normal subjects. Regio ns activated by acupuncture stimulation at Li 4 included the hypothalamus w ith an extension to midbrain, the insula, the anterior cingulate cortex, an d the cerebellum. Of note, it was only the stimulation at Fi 4 that activat ed the hypothalamus under the similar psychophysical ratings of acupuncture sensation (deqi) as elicited by the stimulation at the two points, respect ively. The data suggested that the hypothalamus might characterize the cent ral expression of acupuncture stimulation at the classical analgesic point and serve as one key element in mediating analgesic efficacy of acupuncture stimulation. (C) 2001 Elsevier Science Ireland Ltd. All rights reserved.