Inspiratory phase-locked alpha oscillation in human olfaction: source generators estimated by a dipole tracing method

Area of Science:

• Neuroscience
• Olfactory Perception
• Respiratory Physiology

Background:

• Olfactory perception and emotional responses are closely linked to breathing patterns.
• Understanding the neural mechanisms underlying olfactory processing during respiration is crucial.

Purpose of the Study:

• To investigate changes in respiratory patterns during olfactory stimulation.
• To identify inspiratory-related electroencephalographic potentials and their neural origins.
• To explore the relationship between respiration and olfactory perception.

Main Methods:

• Simultaneous respiration and electroencephalography (EEG) recordings were obtained.
• Participants were exposed to pleasant and unpleasant odors.
• EEG was triggered by inspiration onset to analyze inspiratory-phase locked potentials.
• Dipole tracing was used to estimate the location of neural sources.

Main Results:

• Respiratory frequency decreased with pleasant odor recognition and increased with unpleasant odor detection/recognition.
• A novel inspiratory phase-locked alpha oscillation (I-alpha) was identified during olfactory stimulation.
• I-alpha was localized to limbic areas and specific cortical regions, including the entorhinal cortex, hippocampus, amygdala, and orbitofrontal cortex.

Conclusions:

• Olfactory stimulation significantly alters respiratory patterns.
• Inspiratory phase-locked alpha oscillations (I-alpha) are associated with olfactory processing in the brain.
• These findings suggest the olfactory cortex plays a role in integrating respiratory and olfactory information.