Rachel Wilson, PhD

Mission: The goal of our research is to understand how sensory information is processed by neural circuits, and to describe the mechanisms that underlie sensory processing.

Approach: We use the brain of the fruit fly Drosophila to investigate these questions. This tiny brain contains only ~100,000 neurons, and many individual neurons are uniquely identifiable across flies. Moreover, the powerful genetic toolbox of this organism provides a unique combination of tools for manipulating neural circuits.

Questions: We are characterizing the sensory responses of neurons in several different brain regions, with a particular emphasis on the olfactory system and auditory system. We aim to understand why it might be useful to represent sensory information in this particular format, and why this information is "reformatted' (or "transformed") as it moves from one brain region to another. In parallel, we are investigating the circuit, cellular, and synaptic mechanisms that shape these transformations. Our ultimate goal is to be able to predict what perceptual deficits will result from specific perturbations of neural activity in these circuits.

Techniques: We primarily use electrophysiological techniques (patch clamp recording and extracellular single-unit recording) to record the activity of individual identified neurons in vivo.

To complement these electrophysiological techniques, we use a variety of genetic tools:

• We use the Gal4/UAS system to specifically label small subsets of neurons in the fly brain with fluorescent markers. This allows us to target our recording electrodes specifically to these neurons.
• We image patterns of activity in identified neurons by expressing a genetically-encoded calcium sensor in these neurons under Gal4/UAS control.
• We trace neural circuits by expressing genetically-encoded photoactivatable fluorophores under Gal4/UAS control and photoactivating in specific regions of interest.
• We use genetic tools to perturb patterns of electrical activity in neural circuits by manipulating expression of specific ion channels, receptors, or neurosecretory molecules.

Finally, we measure behavioral responses to sensory stimuli in individual flies. By comparing the impact of specific genetic manipulations on both neural activity and behavior, we aim to understand how patterns of electrical activity in the brain correspond to sensory perceptions.

"Our ultimate goal is to be able to predict what perceptual deficits will result from specific perturbations of neural activity in these circuits."