Mapping of the primary gustatory cortex in human by functional MRI

Abstract

Using MEG we located the primary gustatory cortices (PGC) at the ventral end of the central sulcus (cs) and the transition between the parietal operculum and insula (area G) because of the fastest activation (Kobayakawa, et al, 1999), though MEG can detect activation only inside sulci. This study aimed to examine the extent of the PGC by fMRI using a computer-controlled tastant-delivery system. 12 volunteers (21-33 years old, right-handed), without dysgeusia, participated in the study. The tongue tip was continuously flowed with fluids during the recording session, consisting of at least 5 alternating control and stimulation periods separated with a small air. The stimulation period supplied 16 trials of stimulations, each consisting of 1 M NaCl (ca 1s) followed by 3 water rinse (ca 1s) separated with an air bubble, and the control period supplied water in the same sequence as stimulation. BOLD signals were detected by 1.5 T Siemens MRI scanner (Magnetom Vision) with EPI protocol, and processed using SPM 99. Signals were collected for 5 stimulation periods 9 s after the onset of stimulus period. In all subjects significant activations (1% uncorrected) were found at area G on one or both sides of the hemisphere, and in 58% at the rholandic operculum and cs. In some cases activation continued from area G to the frontal operculum. [Jpn J Physiol 54 Suppl:S177 (2004)]