Olfactory subsystem in rodents: effects of temperature on odour perception

Abstract

In nature, an individual is continuously inundated with multiple sensory stimuli. Adequate reception of information from these stimuli is quintessential for decision-making. The process of decision-making requires activation of sensory peripheral organs that further transmit sensory inputs to higher centers of the brain. One mode of information processing is the activation of parallel neural pathways. Alternatively, information from multiple sensory cues can be integrated, leading to multi-sensory percept formation. Different sensory systems are specialized to detect different kinds of sensory stimuli based on their physicochemical nature. Therefore, information processing through multiple sensory systems is required for multisensory percept formation. However, the rodent olfactory system is known to process information about different types of stimuli. The olfactory system comprises of four subsystems that can detect stimuli of various kinds, e.g., temperature, chemical cues, and mechanical pressure. As a part of my thesis, I investigated decision-making in a temperature and odour dependent task. We used the Go/No-Go operant conditioning paradigm to train the animals to discriminate among different temperatures, different odourants, and different pairs of temperature-odourants coupled stimuli. We observed that the animals were able to perform temperature and odour discrimination tasks accurately. The pace of learning during the multi-sensory scenario was quicker than that of temperature discrimination, however, similar to that of odour discrimination. Our results suggest that odour cues may have higher importance over temperature cues, while animals rely on different olfactory subsystems to make the decisions. Investigating activation profiles in areas receiving information from Main Olfactory Epithelium and Gruenberg Ganglion will facilitate us in determining varying mechanisms for different training paradigms that we used.