Visual EXPRESSO: Automated quantification of real time food ingestion and foraging in Drosophila
The EXPRESSO device automates the conventional CAFE assay and allows us to measure-real-time feeding behavior for extended periods of time for dozens of flies in parallel. The expresso sensor bank consists of five independent feeding channels. Each feeding channel has its own glass feeding capillary which sits along a linear array optical sensor. A micro-controller samples the data from the optical sensor and detects the liquid food level in the capillary. The first version of the Expresso system has allowed us to capture microstructure of food ingestion in flies. We plan to add new features to the Expresso system which will enhance its capacity to capture different steps in feeding behavior.
The EXPRESSO device automates the conventional CAFE assay and allows us to measure-real-time feeding behavior for extended periods of time for dozens of flies in parallel. The expresso sensor bank consists of five independent feeding channels. Each feeding channel has its own glass feeding capillary which sits along a linear array optical sensor. A micro-controller samples the data from the optical sensor and detects the liquid food level in the capillary. The first version of the Expresso system has allowed us to capture microstructure of food ingestion in flies. We plan to add new features to the Expresso system which will enhance its capacity to capture different steps in feeding behavior.
Neural Circuitry for Ingestion in Drosophila
Previously, we have identified local interneurons (IN1) in the fly taste center that receive input from sugar-sensitive pharyngeal taste neurons to control rapid and temporally precise sugar ingestion. To understand how this circuit regulates the timing of ingestion and how it is modulated by satiety, we are searching for neural populations downstream or upstream of IN1 neurons in the fly brain. Further anatomical and functional characterization of these neural subsets and their neurophysiological interactions with IN1 neurons will elucidate how flies regulate the temporal dynamics of food intake decisions.
Previously, we have identified local interneurons (IN1) in the fly taste center that receive input from sugar-sensitive pharyngeal taste neurons to control rapid and temporally precise sugar ingestion. To understand how this circuit regulates the timing of ingestion and how it is modulated by satiety, we are searching for neural populations downstream or upstream of IN1 neurons in the fly brain. Further anatomical and functional characterization of these neural subsets and their neurophysiological interactions with IN1 neurons will elucidate how flies regulate the temporal dynamics of food intake decisions.
Neural Correlates of State-Dependent Food Intake Decisions
To study neural correlates of state dependent decisions, we use custom imaging preparation to record neural activity from molecularly identified populations of neurons and circuits while flies are presented with sensory stimuli such as food or water. We are investigating how the neural circuits that regulate food intake decisions change activity during varying motivational states and sensory experiences. We are also developing chronic imaging methods to capture whole brain neural activity while an individual tethered fly is being deprived from food , directly revealing how neural processing is altered by entry into a different motivational state
To study neural correlates of state dependent decisions, we use custom imaging preparation to record neural activity from molecularly identified populations of neurons and circuits while flies are presented with sensory stimuli such as food or water. We are investigating how the neural circuits that regulate food intake decisions change activity during varying motivational states and sensory experiences. We are also developing chronic imaging methods to capture whole brain neural activity while an individual tethered fly is being deprived from food , directly revealing how neural processing is altered by entry into a different motivational state
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Neural Correlates of Foraging in flies
To quantify foraging decisions in flies, we are developing a virtual foraging assay (VR) based on the automated ball tracking system FICTRAC. In this VR-foraging task, nutrient deprived flies will explore their environment and will be given liquid food in a defined point in VR space in the presence of certain olfactory or visual cues. We will monitor fly’s trajectories before and after the food stimulus and in the presence or absence of visual/olfactory cues. The fly’s behavior will be tracked using a machine vision system that characterizes its position, velocity, and locomotion. Using the VR foraging task, we will identify neurons that regulate foraging decisions in flies. |
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Imaging neural circuit dynamics during ingestion in mice
In mammals, food is detected by the peripheral taste organs; the tongue, palate and the pharynx which are innervated by cranial nerve fibers that project to the nucleus of the solitary tract (NTS). NTS is one of the main visceral sensory nuclei located in the brainstem. It contains functionally distinct populations of neurons that convey information from a range of sensory neurons including the gustatory sensory neurons that innervate peripheral taste organs, and the vagal sensory neurons that innervate the gastrointestinal track. Because of the convergent inputs NTS receives from the peripheral taste organs, and the digestive tract, this brain region is likely to play a critical role in regulating food intake. However, investigating the functions of neurons in the NTS has been technically challenging especially because of the location of this brain area. We are developing a 3P microendoscope that combines the deep imaging capability of long wavelength 3P microscopy with the deep tissue access provided by GRIN lenses to image taste sensitive neurons in the brainstem nucleus, nucleus tractus solitarius (NTS), in awake mice during sugar ingestion with the aim to reveal their function in mediating taste processing at different metabolic states.
In mammals, food is detected by the peripheral taste organs; the tongue, palate and the pharynx which are innervated by cranial nerve fibers that project to the nucleus of the solitary tract (NTS). NTS is one of the main visceral sensory nuclei located in the brainstem. It contains functionally distinct populations of neurons that convey information from a range of sensory neurons including the gustatory sensory neurons that innervate peripheral taste organs, and the vagal sensory neurons that innervate the gastrointestinal track. Because of the convergent inputs NTS receives from the peripheral taste organs, and the digestive tract, this brain region is likely to play a critical role in regulating food intake. However, investigating the functions of neurons in the NTS has been technically challenging especially because of the location of this brain area. We are developing a 3P microendoscope that combines the deep imaging capability of long wavelength 3P microscopy with the deep tissue access provided by GRIN lenses to image taste sensitive neurons in the brainstem nucleus, nucleus tractus solitarius (NTS), in awake mice during sugar ingestion with the aim to reveal their function in mediating taste processing at different metabolic states.