Neuronal mechanisms of bilateral olfactory information-comparison in the mammalian brain

• Applicant: Dr. Mohammad Tariq, Ph.D.
• Subject Area: Cognitive, Systems and Behavioural Neurobiology ; Experimental and Theoretical Network Neuroscience
• Term: since 2025
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 576725275

Background: Understanding the neural representations of the sensory cues within the environment is a central pursuit of neuroscience. Olfaction is one key sensory modality necessary to locate food resources, mates, and shelter as well as to avoid predation. Odors thus guide navigation and decision-making. While neural mechanisms for bilateral visual and auditory information comparison are well characterized, how/if bilateral olfactory information is compared remains unknown. Mounting evidence from behavioral and theoretical work supports that comparison of olfactory information across the two nostrils could serve as a differential guidance signal for animals to locate an odor-source. For auditory stimuli, the auditory information to each ear is compared to locate the source with respect to the head in the horizontal plane. This orienting signal is integrated in superior olivary nucleus (SON), located in brainstem. An olfactory brain area, anterior olfactory nucleus (AON), shares a similar kind of connectivity pattern as that of SON. Furthermore, AON is the first region where connections to the contralateral olfactory brain areas are made. This establishes AON as a likely region for bilateral olfactory comparison. Hypothesis: AON neurons generate comparative/differential signals by integrating the timing or amplitude of odors across the left and right nostrils. Method: Studying bilateral odor comparison in live animals has limitations as the arrival of the odor molecules to nostrils is gated by the sniffing of the animal. The semi-intact rodent nose-brain preparation, routinely used in my host lab, circumvents these issues, allowing for precise manipulation of olfactory amplitude or timing to each of the nostrils with no reliance on sniffing. Conclusion: This project aims to establish the neural mechanisms of bilateral olfactory comparison by recording AON neurons in the rodent nose-brain preparation while delivering precise odor information to each of the nostrils.

• DFG Programme: WBP Position