Olfactory receptor neuron responses coding for rapid odour sampling

Area of Science:

• Neuroscience
• Sensory Biology
• Olfaction Research

Background:

• Vertebrate olfactory receptor neurons (ORNs) respond to odorants rhythmically during natural breathing.
• The capacity of ORNs to encode high-frequency stimulation, especially during rapid sniffing, remains largely unexplored.

Purpose of the Study:

• To investigate how mouse ORNs encode odorant stimuli at different frequencies (2Hz and 5Hz) mimicking natural sniffing.
• To determine the fidelity and speed of the olfactory transduction cascade under varying stimulation frequencies and odorant concentrations.

Main Methods:

• Stimulating mouse ORNs with controlled odorant frequencies (2Hz and 5Hz).
• Analyzing action potential generation, response latency, and encoding reliability at different odorant concentrations.

Main Results:

• ORNs accurately follow low-frequency (2Hz) stimulation with high fidelity at intermediate odorant concentrations.
• High stimulus frequencies (5Hz) and high odorant concentrations significantly reduce action potential generation and response reliability.
• Increased frequency degrades ORN signaling, with high concentrations preventing action potential generation.

Conclusions:

• Olfactory receptor neurons modulate odorant signal processing in a frequency-dependent manner, influenced by sniffing rate.
• ORNs do not merely relay stimulus timing and concentration but actively process sensory information.
• Sniffing behavior critically impacts the fidelity of olfactory information transmitted to the brain.