Olfactory receptor neurons use gain control and complementary kinetics to encode intermittent odorant stimuli

Area of Science:

• Neuroscience
• Olfactory receptor neurons
• Sensory processing

Background:

• Insects navigate using odor plumes with rapidly changing intensities.
• Understanding how olfactory receptor neurons (ORNs) detect natural stimuli is unclear.
• Natural odor signals lack scale, posing a challenge for detection.

Purpose of the Study:

• Investigate how Drosophila ORNs detect naturalistic odor stimuli.
• Determine the mechanisms underlying olfactory sensing of intermittent signals.
• Analyze adaptation and saturation in ORN responses.

Main Methods:

• In vivo stimulation of Drosophila ORNs with naturalistic and Gaussian stimuli.
• Analysis of ORN responses to varying stimulus mean and variance.
• Characterization of gain control mechanisms at transduction and spiking levels.

Main Results:

• Drosophila ORNs adapt to both the mean and variance of odor stimuli.
• Mean-dependent gain control follows the Weber-Fechner relation at transduction.
• Variance-dependent gain control occurs at transduction and spiking.
• Complementary kinetics in transduction and spike generation preserve odor timing.
• ORNs exhibit scale-invariant sensing of odorant encounters.

Conclusions:

• Adaptation and saturation are key to naturalistic olfactory sensing in Drosophila.
• ORNs employ complementary mechanisms to maintain temporal fidelity in spiking.
• Scale-invariant sensing is crucial for insect odor plume navigation.