We are constantly bombarded by the sights, sounds, and smells of the world around us. Many decisions we make are based on the specifics of these sensory stimuli. For example, the visual appeal of beautiful scenery may keep us climbing up a tough hiking trail, but traffic noise from a nearby highway may be loud enough for us to decide it's not worth the effort. In a more mundane situation, we may choose whether or not to eat a particular fruit based on its color, smell, and feel, with past experience guiding how we weight the different factors.
A fundamental goal of sensory neuroscience is to understand how the brain represents and processes such information. Our research focuses on this issue, as well as on the question of how neural circuits integrate information from different modalities. We would like to uncover links between such computations and adaptive decision-making. We believe that exploring such issues requires studying the activity of large populations of neurons in a behaving organism. Furthermore, validating any potential answers will require manipulating neural circuits in precise and well-controlled ways. A suitable model system to use is the fruit fly, Drosophila melanogaster, which has long been the organism of choice for behavioral genetics and comes with tools to fluorescently label, manipulate, and record the activity of genetically targeted neurons.
For the past few years we have been using both electrophysiology and two-photon imaging (often simultaneously) to record from brain neurons in the intact adult fruit fly. For optical imaging, we use genetically encoded sensors (of, for example, calcium), including new indicators developed by Loren Looger's lab at Janelia. The advantage of such sensors is that the same genetically identified neurons can be targeted for imaging in fly after fly. Although these sensors currently lack the temporal resolution to monitor neural activity with single action potential resolution in vivo, they can nonetheless be used to identify foci of interest for more refined recordings using electrophysiological techniques. With this combination of electrophysiological and optical methods, along with a variety of computational techniques, we are exploring neural processing of sensory information underlying simple behaviors.
Our lab is interested in two broad areas of research:
Identification of neurons and circuits in the fly brain involved in multisensory integration: This effort involves using genetic, electrophysiological, and imaging techniques to establish functional connectivity and to map circuits of interest. Our particular obsession is an area of the insect brain, called the central complex, that is considered to be important for sensorimotor processing.
Neural representation of sensory information underlying behavior: We are using existing electrophysiological and optical methods, as well as some in development, to study sensorimotor computations in single neurons and ensembles of neurons. Computational analysis and modeling will be key components of this effort going forward.
A major focus of our lab is to develop improved techniques for monitoring the activity of large numbers of neurons in an intact fly. Our goal is to be able to monitor and manipulate the activity of selected populations of neurons in a behaving fruit fly. In this effort, we are collaborating with other labs at Janelia. To combine high-throughput physiological recordings with fly behavior, we work with other groups at Janelia Farm, including Michael Reiser's lab, the Applied Physics and Instrumentation Group, and the Instrumentation Design and Fabrication Group. Much of the appeal of the fruit fly as a model organism lies in the many molecular tools being developed for it: expertise in this field is abundant at Janelia, and we benefit greatly from research in the labs of Gerry Rubin and Julie Simpson, among others.
Establishing causal links between multimodal computations of neuronal ensembles and the fly's decision-making behavior is a long-term goal for our lab. Along the way, we hope to discover some general principles about sensory representations, neural computation, and the functional organization of small circuits in the fly brain.
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Last updated May 08, 2009
