Diversity of visual inputs to Kenyon cells of the Drosophila mushroom body

• Published in: Nature communications Vol. 15; no. 1; pp. 5698 - 18
• Main Authors: Ganguly, Ishani, Heckman, Emily L., Litwin-Kumar, Ashok, Clowney, E. Josephine, Behnia, Rudy
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 07.07.2024; Nature Publishing Group; Nature Portfolio
• Subjects: 631/378/1595; 631/378/3917; Animals; Cerebral hemispheres; Coding; Combinatorial analysis; Connectome; Drosophila; Drosophila melanogaster - physiology; Fruit flies; Hemispheres; Humanities and Social Sciences; Insects; Interneurons - physiology; multidisciplinary; Mushroom bodies; Mushroom Bodies - cytology; Mushroom Bodies - physiology; Neural coding; Neural networks; Neurons - physiology; Neuropil - cytology; Neuropil - physiology; Olfaction; Olfactory discrimination learning; Olfactory stimuli; Optic lobe; Optic Lobe, Nonmammalian - cytology; Optic Lobe, Nonmammalian - physiology; Population studies; Science; Science & Technology - Other Topics; Science (multidisciplinary); Visual discrimination learning; Visual flight; Visual Pathways - physiology; Visual perception; Visual stimuli
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-024-49616-z

The arthropod mushroom body is well-studied as an expansion layer representing olfactory stimuli and linking them to contingent events. However, 8% of mushroom body Kenyon cells in Drosophila melanogaster receive predominantly visual input, and their function remains unclear. Here, we identify inputs to visual Kenyon cells using the FlyWire adult whole-brain connectome. Input repertoires are similar across hemispheres and connectomes with certain inputs highly overrepresented. Many visual neurons presynaptic to Kenyon cells have large receptive fields, while interneuron inputs receive spatially restricted signals that may be tuned to specific visual features. Individual visual Kenyon cells randomly sample sparse inputs from combinations of visual channels, including multiple optic lobe neuropils. These connectivity patterns suggest that visual coding in the mushroom body, like olfactory coding, is sparse, distributed, and combinatorial. However, the specific input repertoire to the smaller population of visual Kenyon cells suggests a constrained encoding of visual stimuli. The Drosophila mushroom body, a well-studied olfactory learning center, also receives visual input with unknown function. Here, the authors leverage the FlyWire connectome to identify and characterize properties of visual inputs to the mushroom body.