The neuronal basis of amino acid sensing in Drosophila melanogaster
Sensory and Behavioural Biology
Final Report Abstract
Animals adjust their feeding decisions to maintain nutrient homeostasis and to respond to changes in physiological needs. Our knowledge on how animals integrate their current internal states with sensory information in brain processing to perform adapted feeding decisions is very limited. As appropriate feeding decisions are crucial for the health and well-being of all organisms, a detailed understanding of the underlying neuronal processes is very important. In Drosophila, protein deprivation and mating both induce a specific appetite for yeast, the main protein source of fruit flies. I developed a novel imaging approach to investigate how taste processing in the brain of flies is modulated by different internal states. This technique allows to volumetrically record pan-neuronal activity at high resolution across full brain neuropils, while stimulating taste sensory neurons with different taste stimuli. Aligning all recorded 3D data in space enabled me to compare brain activity across flies in different internal states. I used this technique to compare taste induced brain activity in the fly’s taste processing center, the subesophageal zone (SEZ), in flies that had been either fully fed or protein deprived and in flies that were either virgins or mated. To extract response data from the anatomically not well-structured SEZ neuropil, I performed a functional brain segmentation based on the recorded response data. I discovered that metabolic state affected neuronal activity across all processing levels in the SEZ, including taste sensory regions, higher order integrative regions and motor output regions. Importantly, the modulations I found were nutrient specific, affecting the processing of proteinaceous yeast stimuli, but not the processing of water or sucrose stimuli. Particularly, I identified novel higher order taste processing regions in the posterior SEZ, that integrated taste and metabolic state information. Surprisingly, reproductive state, despite also inducing a strong and specific yeast appetite, did influence taste processing in the SEZ more sparsely, mostly affecting motor regions. In summary, in this research project I developed a pan-neuronal imaging approach that I used to tackle the internal state dependent neuronal processing underlying food choice behavior. The results provide important novel insights into the neuronal principles underlying nutrient specific appetites.
Publications
- 2018. An expression atlas of variant ionotropic glutamate receptors identifies a molecular basis of carbonation sensing. Nature Communications 9, 4252
Sánchez-Alcañiz, J.A., Silbering, A.F., Croset, V., Zappia, G., Sivasubramaniam, A.K., Abuin, L., Sahai, S.Y., Münch, D., Steck, K., Auer, T.O., Cruchet, S., Neagu-Maier, G.L., Sprecher, S.G., Ribeiro, C., Yapici, N., Benton, R.
- 2020. Nutrient homeostasis — translating internal states to behavior. Current Opinion in Neurobiology, Neurobiology of Behavior 60, 67–75
Münch, D., Ezra-Nevo, G., Francisco, A.P., Tastekin, I., Ribeiro, C.
(See online at https://doi.org/10.1016/j.conb.2019.10.004)
