RT Journal Article SR Electronic T1 Inhibitory muscarinic acetylcholine receptors enhance aversive olfactory conditioning in adult Drosophila JF bioRxiv FD Cold Spring Harbor Laboratory SP 382440 DO 10.1101/382440 A1 Noa Bielopolski A1 Hoger Amin A1 Anthi A. Apostolopoulou A1 Eyal Rozenfeld A1 Hadas Lerner A1 Wolf Huetteroth A1 Andrew C. Lin A1 Moshe Parnas YR 2018 UL http://biorxiv.org/content/early/2018/08/01/382440.abstract AB Olfactory associative learning in Drosophila is mediated by synaptic plasticity between the Kenyon cells of the mushroom body and their output neurons. Both Kenyon cells and their inputs are cholinergic, yet little is known about the physiological function of muscarinic acetylcholine receptors in learning in adult flies. Here we show that aversive olfactory learning in adult flies requires type A muscarinic acetylcholine receptors (mAChR-A) specifically in the gamma subtype of Kenyon cells. Surprisingly, mAChR-A inhibits odor responses in both Kenyon cell dendrites and axons. Moreover, mAChR-A knockdown impairs the learning-associated depression of odor responses in a mushroom body output neuron. Our results suggest that mAChR-A is required at Kenyon cell presynaptic terminals to depress the synapses between Kenyon cells and their output neurons, and may suggest a role for the recently discovered axo-axonal synapses between Kenyon cells.