Rats track odour trails accurately using a multi-layered strategy with near-optimal sampling

Area of Science:

• Neuroscience
• Animal Behavior
• Olfactory Sensory Processing

Background:

• Olfactory tracking is vital for survival, guiding animals to resources and away from threats.
• Active sampling, where animals control their sensory input, is key to effective odor detection.
• Understanding the mechanisms of precise odor tracking in mammals is crucial for olfactory research.

Purpose of the Study:

• To investigate the accuracy and sampling strategies rats employ when tracking odor trails.
• To determine the neural and behavioral correlates of successful odor trail following.
• To elucidate the multi-layered sensory strategies enabling high-fidelity olfactory navigation.

Main Methods:

• Rats were trained to follow odor trails on a treadmill apparatus.
• Local field potentials (LFPs) from the olfactory bulb and sniffing rates were recorded.
• Nasal occlusion was used to assess the role of each nostril in tracking accuracy.

Main Results:

• Rats tracked odor trails with high accuracy, within approximately 1 cm.
• Sniffing rates, but not olfactory bulb LFPs, differed significantly between tracking and non-tracking states.
• Tracking accuracy decreased when one nostril was occluded.
• Rats exhibited predictive path choices at forks and wide "casting" sweeps when encountering odor gaps.

Conclusions:

• Rats employ a sophisticated, multi-layered strategy for accurate odor trail tracking.
• Efficient sampling and high-precision navigation are achieved through adaptive behavioral responses.
• Sniffing patterns are critical modulators of olfactory performance in active tracking tasks.