Odor Canopy: A Method for Comfortable Odorant Delivery in MRI

Area of Science:

• Neuroimaging
• Sensory Neuroscience
• Biomedical Engineering

Background:

• Functional magnetic resonance imaging (fMRI) is crucial for studying brain responses to stimuli.
• Olfactory fMRI faces challenges due to imaging artifacts and difficulties in controlling odorant delivery.
• Existing odor delivery systems (nasal cannulas, masks) have drawbacks and cause discomfort.

Purpose of the Study:

• To introduce and validate a novel odor delivery system for fMRI of olfaction.
• To address limitations of current odorant delivery methods in the MRI environment.
• To enhance comfort and data quality in olfactory fMRI research.

Main Methods:

• Modification of an MRI head-coil to create an "odor canopy" microenvironment.
• Rapid switching (under 150 ms) of odorants within the odor canopy.
• Proof-of-concept experiments to assess odorant presence/absence detection and comfort levels.
• fMRI data acquisition to evaluate typical olfactory brain responses.

Main Results:

• The odor canopy enables rapid and artifact-free odorant delivery without nasal cannulas or masks.
• Participants reported greater comfort with the odor canopy compared to nasal masks.
• fMRI data demonstrated clear dissociable odorant presence and absence signals.
• Typical olfactory brain responses were observed using the odor canopy system.

Conclusions:

• The odor canopy is a promising innovation for olfactory fMRI.
• This method minimizes discomfort and improves stimulus control in olfactory neuroimaging.
• The odor canopy facilitates more reliable and comfortable studies of the human olfactory system.