Activity Patterns Elicited by Airflow in the Olfactory Bulb and Their Possible Functions

Area of Science:

• Neuroscience
• Olfactory System
• Sensory Physiology

Background:

• Olfactory sensory neurons (OSNs) detect odorants and airflow, but airflow sensing mechanisms are poorly understood.
• Olfactory bulb (OB) odor coding is well-studied, while mechanical stimulation coding remains largely unexplored.
• The functional significance of OSN airflow sensing is largely unknown.

Purpose of the Study:

• To map activity patterns in the rat olfactory bulb elicited by mechanical airflow.
• To investigate the relationship between airflow patterns and physiological parameters.
• To explore the potential functions of airflow sensing in OSNs and the OB.

Main Methods:

• Functional magnetic resonance imaging (fMRI) was used to map activity patterns in male rat OBs.
• Local field potential recordings were correlated with fMRI data.
• Physiological parameters (heart rate, respiratory rate, EEG) were examined in relation to airflow.

Main Results:

• Airflow evoked broader OB activity patterns compared to odorants.
• Pattern intensity increased with airflow, while topography remained consistent.
• Regular airflow decreased heart rate, respiratory rate, and beta-band EEG power.

Conclusions:

• Mechanical airflow signals are transmitted to the OB, which can process this information.
• Airflow sensing by OSNs has functional implications beyond odor detection.
• Olfactory airflow rhythm can regulate physiological and brain states, potentially explaining breath control benefits in practices like meditation and yoga.