Neural control of Drosophila foraging and food ingestion
Oral presentation
Precise regulation of food intake is essential for every animal to survive. Here, we use the fly, Drosophila melanogaster, to identify food intake and foraging circuits from sensory input to motor output to understand the neural computations the brain uses while deciding to consume a particular food source.
We have developed an automated system called Visual Expresso to capture fly foraging and food intake behaviors. This system captures fly locomotion and the dynamics of food intake at high temporal resolution. Visual Expresso data shows that flies regulate their food intake and foraging based on their hunger state and the quality of the food presented. Moreover, we found that hunger and thirst states interact to determine the amount of water or sugar ingested.
We are also working on identifying food intake circuits in flies. Previously, we identified a novel class of excitatory interneurons (IN1) in the fly brain that regulates food ingestion. Recently, we focused on identifying the IN1 food intake circuitry using optogenetics and anterograde trans-synaptic circuit tracing. In these experiments, we first focused on identifying sensory and modulatory inputs to IN1 neurons. We have found that sugar sensing neurons that express Gr64f and Gr43a provide excitatory input to IN1 neurons, whereas the other 2 groups of sugar sensing neurons Gr64a and Gr5a, bitter sensing neurons Gr66a, and water sensing neurons ppk28 cannot significantly activate or inhibit IN1 neurons. Neurons expressing the Gr43a receptor generated a strong and sustained calcium response in IN1 neurons thus we further investigated which Gr43a neurons produce this excitatory effect. Using genetic tools available, we labeled different populations of Gr43a neurons and found that a population of gut sensory neurons is required for IN1 activation. We will present our current results and the model for how the gut-brain axis might regulate state-dependent food intake in flies.
We have developed an automated system called Visual Expresso to capture fly foraging and food intake behaviors. This system captures fly locomotion and the dynamics of food intake at high temporal resolution. Visual Expresso data shows that flies regulate their food intake and foraging based on their hunger state and the quality of the food presented. Moreover, we found that hunger and thirst states interact to determine the amount of water or sugar ingested.
We are also working on identifying food intake circuits in flies. Previously, we identified a novel class of excitatory interneurons (IN1) in the fly brain that regulates food ingestion. Recently, we focused on identifying the IN1 food intake circuitry using optogenetics and anterograde trans-synaptic circuit tracing. In these experiments, we first focused on identifying sensory and modulatory inputs to IN1 neurons. We have found that sugar sensing neurons that express Gr64f and Gr43a provide excitatory input to IN1 neurons, whereas the other 2 groups of sugar sensing neurons Gr64a and Gr5a, bitter sensing neurons Gr66a, and water sensing neurons ppk28 cannot significantly activate or inhibit IN1 neurons. Neurons expressing the Gr43a receptor generated a strong and sustained calcium response in IN1 neurons thus we further investigated which Gr43a neurons produce this excitatory effect. Using genetic tools available, we labeled different populations of Gr43a neurons and found that a population of gut sensory neurons is required for IN1 activation. We will present our current results and the model for how the gut-brain axis might regulate state-dependent food intake in flies.