Hedonic-specific activity in piriform cortex during odor imagery mimics that during odor perception

Area of Science:

• Neuroscience
• Sensory Perception
• Brain Imaging

Background:

• Visual imagery is known to activate visual cortical areas.
• The existence and neural basis of olfactory imagery remain debated.
• Understanding olfactory imagery could reveal broader principles of sensory mental representation.

Purpose of the Study:

• To investigate whether olfactory imagery activates the olfactory cortex.
• To determine if hedonic-specific activity patterns observed in olfactory perception are also present during olfactory imagery.
• To explore the neural correlates of cue-dependent olfactory imagery.

Main Methods:

• Functional magnetic resonance imaging (fMRI) was employed.
• Participants alternated between smelling and imagining pleasant and unpleasant odors.
• Brain activity was measured during both perception and imagery tasks.

Main Results:

• Imagining odors induced activity in olfactory cortical areas, mimicking real odor perception.
• Hedonic specificity was observed: unpleasant odors (real and imagined) elicited greater activity than pleasant odors in specific brain regions.
• Activated regions included the left frontal piriform cortex and left insula for both real and imagined odors.

Conclusions:

• Olfactory imagery is accompanied by activity in primary olfactory cortical structures.
• Mental imagery of sensory events, across modalities, likely involves the activation of primary sensory cortical areas.
• These findings support the existence of olfactory imagery and its shared neural mechanisms with sensory perception.