ABSTRACT

Most animals survive in turbulent air or water environments and are living proof that it is possible to quantify odor signals in complex turbulent flow conditions to track and find sources of odors (such as food, mates, etc.). However, our engineering knowledge is still incapable of formulating simple and effective measurements that will enable man-made systems to predict, navigate and utilize properties of this turbulent flow to locate sources of chemical release. This project builds on recent exciting computational modeling of the neurobiology of organisms by the proposers, which predict that lobsters are capable of estimating not only the concentration of odors but also the time since the last odor was encountered. Lobsters accomplish this by using ensemble competition across a population of olfactory receptor neurons (ORNs), called "bursting ORNs". Bursting ORNs function to compute the time since last encounter of an odor that, along with concentration, can provide a measure of the distance to the odor source. This research will seek to increase understanding of how ORNs perceive odor concentration and intermittency measured within an odor plume, and how this information is integrated within the lobster's brain. An additional major objective is to develop new neurobiology-based theories in the search for odor sources that can be implemented within human-engineered autonomous underwater vehicles that have the ability to navigate in turbulent chemical plumes. This work will enhance defense and civilian applications of a new generation of electronic noses for tracking chemicals in natural or man-initiated disasters. Through this project, there are also excellent resources and outreach opportunities for integrated education and training of students at the intersection of fluid dynamics, neuroscience, computer engineering and information processing. Outreach will be coordinated through the Center of Innovative Brain Machine Interfaces at the University of Florida and will provide opportunities for undergraduate and graduate research, promote neurotechnology innovations, and foster entrepreneurship activities in order to create potential future start-up companies.

This research brings together a multidisciplinary and complementary team of experts, including a fluid dynamicist, a neurobiologist, and an electrical engineer with the very clear goal of understanding and exploiting olfactory scene analysis in turbulent flow. The research will include laboratory experiments of chemical plume mixing and ORN responses to odor encounters by lobsters, theoretical analysis of search optimization, as well as numerical simulations and novel system architecture for electronic noses with the goal of equipping autonomous underwater vehicles with the ability to navigate in turbulent chemical plumes. This will increase our understanding of how bursting olfactory neuron responses are exploited by the olfactory lobe, the first olfactory relay, and how this information is integrated with the odor specific information in the olfactory bulb. Moreover, this work will enhance our understanding of turbulent plume dynamics in order to develop a new neurobiology-based theory in the search for odor sources. Using information obtained from a large-scale plume, the researchers will use the olfactory organs of the lobster as a model system to understand the physical constraints placed on these chemosensors and examine the role of spatial and temporal relationships of odor inputs in the excitation of olfactory receptor neurons. The work will provide a conceptual substrate for olfactory scene analysis informed by neurobiology, which is still in its infancy compared with vision and audition.

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