Investigating the Role of Thermosensation in ‘Multimodal’ Olfactory Perception
1 Laboratory of Neural Circuits and Behaviour (LNCB), Indian Institute of Science Education and Research (IISER), Pune, Maharashtra, 411008, India
Organisms survive in their environment by processing diverse sensory stimuli and forming cohesive percept of external world. The mouse olfactory system, uniquely equipped with subsystems such as the Main Olfactory Epithelium, Septal Organ, Vomeronasal Organ, and Grueneberg Ganglion (GG), enables the detection of olfactory, mechanical, pheromonal, and temperature cues. While these subsystems have been studied independently, their interactions, and the perception of the ‘multimodal’ stimuli remain poorly understood. Additionally, the role of olfactory system in sensing the temperature also remains elusive. Here we focus on examining the effect of temperature on olfactory perception. First, we studied the ability of animals to discriminate temperatures inherent to their natural habitat, concurrently examining the involvement of GG in temperature perception. To accomplish it, we built a thermo-olfactometer capable of delivering odorized/non-odorized air of desired temperatures and standardized the required parameters. In a temperature discrimination task, mice reached accurate performance levels (>80%) in a few hundred trials, which was lost on the axotomization of GG, indicating a potential role of GG in temperature perception. Further, to reveal the impact of temperature on olfactory perception, animals were subjected to a multimodal discrimination task wherein they were trained to discriminate different odours coupled to different temperatures. Our results showed a faster learning in discrimination of multimodal stimuli (temperature and odour combined) compared to unimodal stimuli (temperature or odour alone) discrimination. Collectively, our findings elucidate the animals’ ability to discriminate varying temperatures through the Grueneberg Ganglion and the possible role of temperature in modulating olfactory perception.