| Taste is one of the basic oral functions, which has a very closely relationship with brain functions. For a long time plenty of studies have been conducted on the anatomic structure and physiologic functions of tongue and tastes. However, limited by technology, there was little known about the location of the gustatory pathways and the taste cortical areas. Recently, with the development of neurosurgery as well as medical imaging, more attentions have been paid to the research in this field. About the taste centrum, many studies have been done, but the results were not identical, which involved in different brain cortex and sub cortical structure. Moreover, in those studies the classification of taste was so rough (pleasant and unpleasant), which led to the location of taste centrum indiscriminate. The purpose of present study was to study the sweet tastecortical areas with PET and SPM (statistical parametric mapping) software, then to provide a foundation to further reveal the relationship between taste stimulation and brain functions.[PURPOSE] To analyze the changes of glucose metabolism in human brain caused by sweet taste stimulation, then locate the sweet taste centrum in the human brain primarily.[SUBJECTS AND METHODS] Six subjects, all right-handed, three men and three women, served as normal volunteers. Each was healthy, had no oral disease, and had similar educational background. Performed as the self-contrast of randomized paired design. The stimulations were given to subjects through sterilized cotton ball with size about 1cmX1cmX1cm, which were soaked in distilled water and 50% sucrose solution respectively for ready (house temperature). When used, those cotton balls were placed on the tongue of subject. During the experiment, PET scan was performed twice in each subject: a control state with distilled water cotton balls and a sweet taste state with sucrose solutioncotton balls.Using visual analysis to observe the PET images of sweet taste stimulation compared with those in the control state.Using Statistical Parameters Mapping (SPM) method to analyze thePET data. The data were calculated to compare the results of subjects in sweet taste and control state after normalizing and smoothing. Each subject's sequential PET images were transformed into spatial coordinates of a standard brain atlas, to investigate the variation of glucose metabolism in whole-brain measurements, and to generate normalized t value maps of variation in glucose metabolism during sweet taste stimulation compared with the control state. Then to locate the sweet stimulation activation areas in brain, according to the brodmann area.[RESULT] Visual analysis showed that the difference of PET images in the two groups was no evident. After computed and compared with SPM, the result showed that there were significant increase in glucose metabolism at insular lobe, parietal lobe, hippocampi, dorsal thalamus, superior frontal gyrus, middle frontal gyrus, posterior limb of internal capsule and inferior temporal gyrus in brains of volunteers in the sweet taste stimulation state compared with the control state (p<0.005 unconnected).[CONCLUSION] The 98 percents energy needed by human brain is generated by glucose metabolism in vivo. The brain has the character of function-blood-metabolism, trinity method for optimization, which provides us the access to study the special regions through tracing the glucosemetabolism in brain with the radiator 18F-FDG. In conclusion, we primarily consider that right insular lobe, right inferior temporal gyrus, left superior parietal lobule, left superior frontal gyrus, left middle frontal gyrus and left insular lobe in brain are sweet taste centrum. Right hippocampi, right posterior limb of internal capsule and left dorsal thalamus are also involved in the process of sweet taste stimulation. |
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