258 | Olfactory sensory adaptation: role and mechanisms

Sensory and Motor Systems

Author: Federico Andres Gascue | Email: fgascue@gmail.com

Federico Gascue , Nicolás Pírez , Fernando Locatelli

1° Instituto de Fisiología, Biología Molecular y Neurociencias; UBA-CONICET / Departamento de Fisiología, Biología Molecular y Celular, Facultad de Ciencias Exactas y Naturales, UBA

The olfactory system is exposed to a diversity of chemical stimuli, needing continuous adjustment based on the animal’s experience. Sensory adaptation, an important mechanism of modulation, is defined as the reduced sensitivity or response to persistent stimuli. Our study investigates olfactory sensory adaptation using honeybees, focusing on mechanisms, temporal aspects, and behavioral effects. Olfactory receptor neurons (ORN) activity was measured via electroantennograms. Adaptation’s induction, duration, and recovery were characterized, alongside with odor identity. Furthermore, to study the behavioral implications of adaptation for the animal, we conducted classical conditioning experiments using odorant mixtures. These experiments showed that adaptation reduces appetitive learning of adapted stimuli, while it enhanced learning of minor mixture’s components that normally would stay occluded. We also conducted calcium imaging experiments of antennal lobe projection neurons (PN), which allowed us to observe adaptation-induced neural representation changes. Lastly, a computational model mirrored experimental outcomes, suggesting that reduced ORN and PN responses are sufficient for adaptation, without the need of central plasticity. Overall, our results emphasize that sensory adaptation is critical in maintaining the olfactory system unsaturated and ready to detect changes in the olfactory context.