Multimodal olfaction: Neural circuit mechanisms of dual modality sensing by the olfactory system

19th September 2024

Timing : 1 pm EST

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For a list of all talks at the NanoBio seminar Series Fall'24, see here


Delivering a needful action requires different prior steps – sensation, perception and decision-making. Our sense organs collect information from the external environment and convert the physical/chemical energy to neural representations. Pre-cortical and cortical neurons refine these representations, and generate a percept, which ultimately leads to a specific behavior. How do we study the complex circuit mechanisms underlying brain disorders? In our laboratory at IISER-Pune we probe olfactory perception and decision- making in healthy subjects and patients with olfactory dysfunctions, and investigate the neural circuit mechanisms using mouse models.

The subsystems present in rodent nose make it a unique sensory organ by imparting the abilities to detect chemical, mechanical and thermal stimuli. However, the neural mechanisms underlying ‘multimodal’ olfaction remain elusive. Recent results from our lab show that mice can discriminate various airflow rates accurately even in the absence of whiskers, through their nose. During the anemo-discrimination task, mice exhibited sniffing refinement indicating the orthonasal airflow information processing. Further, the stimulus-dependent, and learning-dependent calcium signals revealed the role of olfactory bulb inhibitory circuits in refining airflow-related information. Genetic perturbation of AMPAR function and optogenetic control bidirectionally shifted airflow discrimination learning pace, with contrasting phenotypes observed for odor learning. This implies varying optimal inhibition needed for the refinement of olfactory and airflow information. Strikingly, an enhancement in discrimination learning pace had resulted by combining odor and mechanical stimuli at subthreshold levels, confirming the facilitation of olfactory perception by mechanical stimuli. In my talk, I will discuss these results and explain how we use electrophysiological and optogenetic tools in mouse models for studying circuit mechanisms of brain disorders.



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Dr. Nixon M. Abraham
Associate Professor
Wellcome Trust DBT India Alliance Senior Fellow
Indian Institute of Science Education and Research (IISER)
Pune, India