Taste, besides smell, contributes to our experience of environment, from the pleasure of eating to the formation of childhood memories. How are the information about taste qualities (e. g. salty, sour, sweet, and bitter) and intensity represented by activity in the nervous system? This question lies at the center of a long-standing debate in the field of gustatory neurobiology. In that time, two major theories have emerged that have dominated the literatures. There are the labeled-line theory and the across-neuron-pattern theory. However, it is not yet clear how the nervous systems process the information about taste quality and intensity. On the other hand, we seldom recognize experience of pure taste. Taste recognition is strongly influenced by other senses such as vision and smell. Vision and smell have shown to enhance or suppress taste perception. Moreover, orbitofrontal cortex (OFC) is knwon to play an important role in the integration of gustatory and other sensory information. However little is known about the neural mechanism underlying the modulation of taste perception induced by vision and smell. We are concerned with the enhancement or suppression of taste perception induced by smell. It has been reported that taste perception is enhanced or suppressed by smell [1]. To address the neural mechniam underlying the modulation of taste perception elicted by smell, we developed a neural model of the gustatory system including the primary gustatory cortex (GC) and the OFC. Using this model, we show that the GC integrates the information of taste components encoded by the hindbrain and represents the information of a taste as a temporal sequence of dynamical attractors. We also show that the modulation of taste perception by smell is caused by the difference in the spatial fluctuation of GC activity evoked by tastes. The present study provides a new insight into understanding the neural mechnaims by which taste perception is modulated by smell.

[1] Stevenson, R J et al. Chem Senses, 24;627-635 (1999).