The wiring diagram of a glomerular olfactory system
Matthew E Berck,
Avinash Khandelwal,
Lindsey Claus,
Luis Hernandez-Nunez,
Guangwei Si,
Christopher J Tabone,
Feng Li,
James W Truman,
Rick D Fetter,
Matthieu Louis,
Aravinthan DT Samuel,
Albert Cardona
Affiliations
Matthew E Berck
Department of Physics, Harvard University, Cambridge, United States; Center for Brain Science, Harvard University, Cambridge, United States
Avinash Khandelwal
EMBL-CRG Systems Biology Program, Centre for Genomic Regulation, The Barcelona Institute of Science and Technology, Barcelona, Spain; Universitat Pompeu Fabra, Barcelona, Spain
Lindsey Claus
Department of Physics, Harvard University, Cambridge, United States; Center for Brain Science, Harvard University, Cambridge, United States
Luis Hernandez-Nunez
Department of Physics, Harvard University, Cambridge, United States; Center for Brain Science, Harvard University, Cambridge, United States
Guangwei Si
Department of Physics, Harvard University, Cambridge, United States; Center for Brain Science, Harvard University, Cambridge, United States
EMBL-CRG Systems Biology Program, Centre for Genomic Regulation, The Barcelona Institute of Science and Technology, Barcelona, Spain; Universitat Pompeu Fabra, Barcelona, Spain
Aravinthan DT Samuel
Department of Physics, Harvard University, Cambridge, United States; Center for Brain Science, Harvard University, Cambridge, United States
The sense of smell enables animals to react to long-distance cues according to learned and innate valences. Here, we have mapped with electron microscopy the complete wiring diagram of the Drosophila larval antennal lobe, an olfactory neuropil similar to the vertebrate olfactory bulb. We found a canonical circuit with uniglomerular projection neurons (uPNs) relaying gain-controlled ORN activity to the mushroom body and the lateral horn. A second, parallel circuit with multiglomerular projection neurons (mPNs) and hierarchically connected local neurons (LNs) selectively integrates multiple ORN signals already at the first synapse. LN-LN synaptic connections putatively implement a bistable gain control mechanism that either computes odor saliency through panglomerular inhibition, or allows some glomeruli to respond to faint aversive odors in the presence of strong appetitive odors. This complete wiring diagram will support experimental and theoretical studies towards bridging the gap between circuits and behavior.
