Molecular Transduction and Combinatorial Encoding in the Early Olfactory System of the Fruit Fly

We briefly describe below our work on in vivo recordings in the antenna and the antennal lobe of the fruit fly as well as modeling the transduction and combinatorial encoding of the olfactory sensory neurons.

In Vivo Recordings in the Early Olfactory System

We believe that the lack of a deeper understanding of how Olfactory Sensory Neurons (OSNs) encode odorants has fundamentally hindered progress in understanding olfactory signal processing in higher brain centers. Moreover, the lack of precise stimulus delivery and measurement systems has fundamentally limited the progress of functional identification in olfaction.

To address this limitation, we developed a novel in vivo experimental setup with precise and reproducible delivery of airborne stimuli. This experimental setup enabled us to apply system identification methods to OSNs in Drosophila. We applied time-varying odorant stimuli and recorded in vivo the response of Projection Neurons (PNs) postsynaptic to OSNs. These novel type of recordings have shown that individual OSNs and PNs encode the gradient and acceleration of odorant concentration waveforms, respectively. This research was performed in collaboration with Dr. Richard Axel in the Axel Laboratory.

  1. Anmo J. Kim, Aurel A. Lazar and Yevgeniy B. Slutskiy, System Identification of Drosophila Olfactory Sensory Neurons , Journal of Computational Neuroscience, Vol. 30, No.1, February 2011, pp. 143-161, Special Issue on Methods of Information Theory.
  2. A.J. Kim, A.A. Lazar, and Y.B. Slutskiy, Projection Neurons in Drosophila Antennal Lobes Signal the Acceleration of Odor Concentrations, eLife 2015;10.7554/eLife.06651, June 2015.
  3. A.A. Lazar and C.-H. Yeh, Functional Identification of an Antennal Lobe DM4 Projection Neuron of the Fruit Fly, Computational Neuroscience Meeting, Volume 15, July 2014, Québec City, Canada.

Molecular Computing Models of the Early Olfactory System

The antenna and the antenna lobe of the early olfactory system of the fruit fly brain are, respectively, described by the publications below. Open source code and documentation will be available at

  1. Aurel A. Lazar and Chung-Heng Yeh, A Parallel Processing Model of Drosophila Olfactory Sensory Neurons and Its Biological Validation, Neurokernel Request for Comments, Neurokernel RFC #10, December 2017.
  2. Aurel A. Lazar and Chung-Heng Yeh, A Molecular Odorant Transduction Model and Combinatorial Encoding in the Drosophila Antennae, Computational Neuroscience Meeting (featured oral presentation), July 13-18, 2018, Seattle, WA.
  3. Aurel A. Lazar and Chung-Heng Yeh, The Channel: A Canonical Neural Circuit Abstraction of the Fruit Fly Antennal Lobe Construction and Composition Rules, Neurokernel Request for Comments, Neurokernel RFC #11, 2018, to appear.

The Bionet Group is supported by grants from


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