Single-cell type analysis of wing premotor circuits in the ventral nerve cord ofDrosophila melanogaster

Abstract

To perform most behaviors, animals must send commands from higher-order processing centers in the brain to premotor circuits that reside in ganglia distinct from the brain, such as the mammalian spinal cord or insect ventral nerve cord. How these circuits are functionally organized to generate the great diversity of animal behavior remains unclear. An important first step in unraveling the organization of premotor circuits is to identify their constituent cell types and create tools to monitor and manipulate these with high specificity to assess their function. This is possible in the tractable ventral nerve cord of the fly. To generate such a toolkit, we used a combinatorial genetic technique (split-GAL4) to create 195 sparse driver lines targeting 198 individual cell types in the ventral nerve cord. These included wing and haltere motoneurons, modulatory neurons, and interneurons. Using a combination of behavioral, developmental, and anatomical analyses, we systematically characterized the cell types targeted in our collection. Taken together, the resources and results presented here form a powerful toolkit for future investigations of neural circuits and connectivity of premotor circuits while linking them to behavioral outputs.

Transforming descending input into behavior: The organization of premotor circuits in theDrosophilaMale Adult Nerve Cord connectome

“…Wing and haltere MNs. To determine the target muscle for wing and haltere MNs, we matched the MN dendrite morphology in MANC to light microscopy image volumes of MNs with known muscle targets (Ehrhardt et al, 2023), or for three MNs identified their muscle targets in new or (basalar, b1-3; first axillary, i1, i2; third axillary, iii1, iii3, iii4; fourth axillary, hg1-4), and indirect control muscles (tergopleural,tp;pleurosternal,ps1,ps2;tergotrochanteral,TTM). The hg2 muscle in the lateral view, and the power muscles and TTM in the medial view are omitted for clarity.…”

Nested neural circuits generate distinct acoustic signals during Drosophila courtship

“…Table 1. Finally, in cases where cell types described here resemble those targeted in a recently published collection of split-GAL4 reagents targeting wing neurons 56 , we note the possible matches in Sup. Table 1.…”

“…Electrical recordings from possible tp1 and tp2 muscles suggest that they are active during the wing stroke of pulse and sine song ( 37 ; called b3 and b4). tp2 motor neuron silencing phenotypes are currently inconsistent across studies 39,56 , but silencing the tpn motor neurons was shown to abolish pulse and sine song 39 . There are no direct connections from the core song circuit to tp2, but tp1 and tpn are weakly innervated by TN1A and dMS2.…”

“…There are no direct connections from the core song circuit to tp2, but tp1 and tpn are weakly innervated by TN1A and dMS2. Silencing ps1 motor neurons produces pulse-specific phenotypes 34,39,56 . Consistent with this, the ps1 motor neurons are innervated almost exclusively by vMS12 (Figure 8D, Sup.…”

Wings of Change: aPKC/FoxP-dependent plasticity in steering motor neurons underlies operant selflearning inDrosophila

“…Our results above (Fig. 3) will now allow us to select more specific driver lines, expressing only in the identified wing steering MNs (Ehrhardt et al, 2023), which may yield FoxP knock-out flies (or any other manipulation) with sufficient flight performance.…”