Tastes and retronasal odours evoke a shared flavour-specific neural code in the human insula

Area of Science:

• Neuroscience
• Sensory Science
• Food Science

Background:

• Flavor perception arises from the integration of taste and retronasal olfactory signals.
• The neural mechanisms underlying this crossmodal integration in the human brain, particularly in the insula, are not fully understood.

Purpose of the Study:

• To investigate whether retronasal odorants elicit similar neural encoding patterns in the insula as their paired tastants.
• To explore the cortical integration of gustatory and olfactory sensory information during flavor perception.

Main Methods:

• Utilized a flavor-binding paradigm with healthy participants.
• Employed functional magnetic resonance imaging (fMRI) to capture brain activity.
• Applied multivariate pattern analysis (MVPA) to analyze neural representations of tastes and odors.

Main Results:

• Multivariate pattern analysis successfully classified retronasal odors within the insula.
• Overlapping neural representations were found between retronasal odors and their associated tastes, especially in the ventral anterior insula.
• Temporal drift in taste representations within the insula was observed, consistent with findings in rodent gustatory cortex.

Conclusions:

• Retronasal olfactory stimuli evoke neural patterns in the insula that overlap with those of gustatory stimuli, supporting a unified neural basis for flavor.
• These findings highlight the significant crossmodal interactions between gustatory and retronasal olfactory processing in constructing the flavor percept.