Taste memory induces brain activation as revealed by functional MRI

Purpose: Our goal was to use functional MRI (fMRI) to measure brain activat ion in response to imagination of tastes in humans. Method: fMR brain scans were obtained in 31 subjects (12 men, 19 women) usi ng multislice FLASH MRI and echo planar imaging (EPI) in response to imagin ation of tastes of salt and sweet in coronal sections selected from anterio r to posterior temporal brain regions. Activation images were derived using correlation analysis, and ratios of areas of brain activated to total brai n areas were calculated. Total activated pixel counts were used to quantita te regional brain activation. Results: Activation was present in each section in all subjects after imagi nation of each tastant. Activation was similar in response to imagination o f either salt or sweet and was quantitatively similar to that previously re ported in response to imagination of odors of banana and peppermint. Activa tion was similar in both men and women as opposed to previous results of od or memory in which activation in men was greater than in women. However, su bjective responses of intensity of imagined tastes were significantly great er than those previously obtained for odor memory and were consistently, al beit not significantly, greater in women than in men, similar to results pr eviously reported for odor memory. Brain regions activated in response to t aste imagination were consistent with regions previously described as invol ved with actual taste perception in both humans and animals. Regional brain localization for salt and sweet memories could not be differentiated. Conclusion: These studies indicate that (a) tastes can be imagined, (b) bra in regions activated for taste imagination are consistent with regions prev iously described for actual taste perception, and (c) similar to odor memor y for banana and menthone, regional brain localization for salt or sweet ta ste memories could not be differentiated.