Department of Molecular Brain Physiology and Behavior, LIMES Institute, University of Bonn, Bonn, Germany; Department of Zoology, University of Cambridge, Cambridge, United Kingdom
Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
Richard D Fetter
Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States; Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, United States
Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States; Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, United Kingdom
We reconstructed, from a whole CNS EM volume, the synaptic map of input and output neurons that underlie food intake behavior of Drosophila larvae. Input neurons originate from enteric, pharyngeal and external sensory organs and converge onto seven distinct sensory synaptic compartments within the CNS. Output neurons consist of feeding motor, serotonergic modulatory and neuroendocrine neurons. Monosynaptic connections from a set of sensory synaptic compartments cover the motor, modulatory and neuroendocrine targets in overlapping domains. Polysynaptic routes are superimposed on top of monosynaptic connections, resulting in divergent sensory paths that converge on common outputs. A completely different set of sensory compartments is connected to the mushroom body calyx. The mushroom body output neurons are connected to interneurons that directly target the feeding output neurons. Our results illustrate a circuit architecture in which monosynaptic and multisynaptic connections from sensory inputs traverse onto output neurons via a series of converging paths.
