Perception of odor-induced tastes following insular cortex lesion

Abstract

Lesions of the insula can affect olfaction and gustation. Here, we examined the effect of insula lesions on taste and taste-like experiences generated via smelling (i.e., odor-induced tastes) in patients with focal insula lesions and intact olfaction. From a set of 16 patients with lesions to the insula, we found 7 (6 with right-sided lesions) who performed normally on various olfactory measures. These were compared to 42 normal control subjects on tests of gustatory and odor-induced taste perception as well as control measures. The patients were impaired relative to controls on most gustatory measures. They were also impaired on tests of odor-induced taste perception, primarily for stimuli presented on the left side. Examining cases individually revealed evidence of a dissociation: two patients exhibited no impairment in odor-induced taste perception in spite of gustatory deficits. Together, these findings suggest that the insula mediates taste recognition, hedonics, and intensity judgments as well as odor-induced taste perception. However, the areas responsible for aspects of taste perception and those responsible for odor-induced taste do not fully overlap each other and they are also independent of olfactory areas.

Keywords:

• insula lesion
• gustation
• synesthesia
• odor-induced taste
• chemical senses

Acknowledgments

The authors would like to thank the ARC for their support, including the ARC Centre of Excellence grant on Cognition and Its Disorders. We acknowledge Zoe Thayer, Kylie Richardson, Zoe Terpening, and Tracey Shaw for their assistance with data collection. We are also grateful to the participants who volunteered their time for this project.