"Brain Activation Study by Acupuncture" / 全日本鍼灸学会雑誌

ABSTRACT

In this paper we introduce recent developments in the studies of brain activation during somatosensory stimulationexploiting new technologies. Somatosensory stimulation such as acupuncture, inauces tocai activation in tne central nervous system. The electroencephalogram is a popular method to investigate this activation, however, it is difficult to identify the exact location of the activation site. Recent new technologies may provide more accurate localization. Besides magnetoencephalography (MEG), which recognizes the activated brain areas by an evoked magnetic field with induced current, two other methodologies, which take advantage of physiological phenomena occurring during brain activation, were used in this functional study. Following excitation of neurons, brain tissue is supplied with oxygen from oxyhemoglobin causing oxyhemoglobin to turn into deoxyhemoglobin. As a consequence deoxyhemoglobin increases in the brain tissue. In the near-infrared spectrum, the deoxyhemoglobin absorption peak shows higher signal intensity than that of oxyhemoglobin, for which reason activated brain areas can be identified by absorption maps. In functional magnetic resonance imaging (fMRI) activated area can be revealed with high spatial resolution due to the change in magnetic susceptibility of deoxygeneated blood. This paper describes fMRI studies employing these three methods for the evaluation of experiments using acupuncture for focal brain activation.