抄録
The gustatory-related regions of the cerebral cortex in human beings have been the issue of argument for a long time since Penfield and Boldrey (1937). Recent development of imaging techniques, however, has yielded various non-invasive methods, e.g., fMRI, PET and MEG, and allows us to measure the cerebral activities of living human subjects without surgical invasion. Among them, MEG has good temporal resolution, and can give a good estimation of the location of the activity much more precisely than EEG, because the magnetic field generated from living brain is free from distortion by the skull. MEG is, therefore, the most appropriate method to investigate the primary gustatory cortex in human.
We investigated the primary gustatory cortex (PGC) using a tactile-free taste delivery system and MEG, and found the activation at the transition between the parietal operculum and insula with the shortest latency. The ventral end of central sulcus was also activated with almost the same latency in the case of NaCl stimulation. The average latencies of activation were about 120 ms for NaCl and 220 ms for saccharin. In the range of 30 mM to 1M NaCl, the magnitude of ECD in the PGC increased significantly in a concentration-dependent manner. The cortical activation for saccharin was suppressed by gymnemate.
These results suggest that the transition area between the parietal operculum and the insula and the ventral end of the central sulcus are the PGC in human, which is posterior to the PGC in subhuman primates. [Jpn J Physiol 54 Suppl:S20 (2004)]
