Electrical stimulation of the insular cortex induces flavor-preferences in rats.

The present study examined the role of the Insular cortex (IC) in flavor-guided behavior. For that purpose, a flavored stimulus was paired with delayed electrical stimulation of this region. In addition, a standard operant task explored the involvement of the IC in a prefrontal self-stimulation reward-circuit. The results showed strong preferences for the flavored stimulus previously paired to the Insular stimulation, in a discriminative free choice test. However, the operant task revealed a failure to induce IC self-stimulation, suggesting that flavor preferences elicited by electrical stimulation of the IC are not due to activation of the prefrontal-stimulation reward circuit. These results are discussed in terms of the Insular Cortex as critical in processing visceral stimulus, hedonic valence and/or food-reward incentive learning.