The connectome of the adult Drosophila mushroom body provides insights into function

• DOI: 10.7554/elife.62576
• Publication Date: 2020-12-14T15:10:48Z
• Authors: Feng Li; Jack W Lindsey; Elizabeth C Marin; Nils Otto; Marisa Dreher; Georgia Dempsey; Ildiko Stark; Alexander S Bates; Markus William Pl...; Philipp Schlegel; Aljoscha Nern; Shin-ya Takemura; Nils Eckstein; Tansy Yang; Audrey Francis; Amalia Braun; Ruchi Parekh; Marta Costa; Louis K Scheffer; Yoshinori Aso; Gregory SXE Jefferis; Larry F Abbott; Ashok Litwin-Kumar; Scott Waddell; Gerald M Rubin
• Keywords: 0301 basic medicine; Brain Mapping; 0303 health sciences; learning; D. melanogaster; QH301-705.5; behavior; Science; Q; R; neuronal circuits; memory; neuroscience; 03 medical and health sciences; Drosophila melanogaster; Connectome; Medicine; Animals; Biology (General); dopamine; Mushroom Bodies; Neuroscience

Making inferences about the computations performed by neuronal circuits from synapse-level connectivity maps is an emerging opportunity in neuroscience. The mushroom body (MB) is well positioned for developing and testing such an approach due to its conserved neuronal architecture, recently completed dense connectome, and extensive prior experimental studies of its roles in learning, memory, and activity regulation. Here, we identify new components of the MB circuit inDrosophila, including extensive visual input and MB output neurons (MBONs) with direct connections to descending neurons. We find unexpected structure in sensory inputs, in the transfer of information about different sensory modalities to MBONs, and in the modulation of that transfer by dopaminergic neurons (DANs). We provide insights into the circuitry used to integrate MB outputs, connectivity between the MB and the central complex and inputs to DANs, including feedback from MBONs. Our results provide a foundation for further theoretical and experimental work.