Axo-axonic inhibition suppresses Kenyon cell output in the Drosophila mushroom body

Authors: Yudi Wu, Albert Cardona

Presentation type: Poster at SNUFA 2026 online workshop (4-5 Nov 2026)

Abstract

n the Drosophila mushroom body, the APL neuron provides widespread inhibition that helps maintain sparse Kenyon-cell (KC) activity, a key feature of mushroom-body function. KCs also form axo-axonic inhibitory connections with one another, but the functional role of these connections remains unclear. We used a two-compartment Izhikevich model constrained by the EM-derived PN-KC-APL connectome to test how KC-KC inhibition shapes KC axonal output.

We compared responses to an odour stimulus (A) with responses to the same odour combined with optogenetic activation of a second projection neuron population (A+opto), asking whether the recruitment of additional KCs further suppresses the output of odour-A-responsive KCs.

Enabling KC-KC inhibitory connections hyperpolarized KC axons and substantially reduced their synaptic output. However, recruiting the second PN population did not reduce output from the odour-A-responsive KCs below the level evoked by odour A alone. These results suggest that axo-axonic KC-KC inhibition acts primarily as a brake on KC axonal output through axonal hyperpolarization, rather than producing additional input-dependent suppression of an active KC ensemble.

Are you the author and do you want to add some related links to this page? If so, check out our guide to adding related links and videos.