Descending control of motor sequences in

Simpson, Julie H.

doi:10.1016/j.conb.2023.102822

Cited by 7 publications

(2 citation statements)

References 83 publications

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“…Many DNs identified at light level have been associated with specific behaviours, specific sensory stimuli and evoked motor programs ( Simpson, 2024 ). We have previously described the wide range of motor circuits targeted by the DNs population in the male VNC (H. S. J.…”

Section: Resultsmentioning

confidence: 99%

Comparative connectomics of the descending and ascending neurons of theDrosophilanervous system: stereotypy and sexual dimorphism

Stürner,

Brooks,

Capdevila

et al. 2024

Preprint

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In most complex nervous systems there is a clear anatomical separation between the nerve cord, which contains most of the final motor outputs necessary for behaviour, and the brain. In insects, the neck connective is both a physical and information bottleneck connecting the brain and the ventral nerve cord (VNC, spinal cord analogue) and comprises diverse populations of descending (DN), ascending (AN) and sensory ascending neurons, which are crucial for sensorimotor signalling and control.Integrating three separate EM datasets, we now provide a complete connectomic description of the ascending and descending neurons of the female nervous system ofDrosophilaand compare them with neurons of the male nerve cord. Proofread neuronal reconstructions have been matched across hemispheres, datasets and sexes. Crucially, we have also matched 51% of DN cell types to light level data defining specific driver lines as well as classifying all ascending populations.We use these results to reveal the general architecture, tracts, neuropil innervation and connectivity of neck connective neurons. We observe connected chains of descending and ascending neurons spanning the neck, which may subserve motor sequences. We provide a complete description of sexually dimorphic DN and AN populations, with detailed analysis of circuits implicated in sex-related behaviours, including female ovipositor extrusion (DNp13), male courtship (DNa12/aSP22) and song production (AN hemilineage 08B). Our work represents the first EM-level circuit analyses spanning the entire central nervous system of an adult animal.

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Section: Resultsmentioning

confidence: 99%

Comparative connectomics of the descending and ascending neurons of theDrosophilanervous system: stereotypy and sexual dimorphism

Stürner,

Brooks,

Capdevila

et al. 2024

Preprint

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“… To convert intentions into actions, movement instructions must pass from the brain to downstream motor circuits through descending neurons (DNs). These include small sets of command-like neurons that are sufficient to drive behaviours 1 —the circuit mechanisms for which remain unclear. Here we show that command-like DNs in Drosophila directly recruit networks of additional DNs to orchestrate behaviours that require the active control of numerous body parts.…”

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confidence: 99%

Descending networks transform command signals into population motor control

Braun,

Hurtak,

Wang-Chen

et al. 2024

Nature

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To convert intentions into actions, movement instructions must pass from the brain to downstream motor circuits through descending neurons (DNs). These include small sets of command-like neurons that are sufficient to drive behaviours1—the circuit mechanisms for which remain unclear. Here we show that command-like DNs in Drosophila directly recruit networks of additional DNs to orchestrate behaviours that require the active control of numerous body parts. Specifically, we found that command-like DNs previously thought to drive behaviours alone2–4 in fact co-activate larger populations of DNs. Connectome analyses and experimental manipulations revealed that this functional recruitment can be explained by direct excitatory connections between command-like DNs and networks of interconnected DNs in the brain. Descending population recruitment is necessary for behavioural control: DNs with many downstream descending partners require network co-activation to drive complete behaviours and drive only simple stereotyped movements in their absence. These DN networks reside within behaviour-specific clusters that inhibit one another. These results support a mechanism for command-like descending control in which behaviours are generated through the recruitment of increasingly large DN networks that compose behaviours by combining multiple motor subroutines.

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Insect Flight: State of the Field and Future Directions

Treidel,

Deem,

Salcedo

et al. 2024

Integrative and Comparative Biology

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The evolution of flight in an early winged insect ancestral lineage is recognized as a key adaptation explaining the unparalleled success and diversification of insects. Subsequent transitions and modifications to flight machinery, including secondary reductions and losses, also play a central role in shaping the impacts of insects on broadscale geographic and ecological processes and patterns in the present and future. Given the importance of insect flight, there has been a centuries-long history of research and debate on the evolutionary origins and biological mechanisms of flight. Here, we revisit this history from an interdisciplinary perspective, discussing recent discoveries regarding the developmental origins, physiology, biomechanics, and neurobiology and sensory control of flight in a diverse set of insect models. We also identify major outstanding questions yet to be addressed and provide recommendations for overcoming current methodological challenges faced when studying insect flight, which will allow the field to continue to move forward in new and exciting directions. By integrating mechanistic work into ecological and evolutionary contexts, we hope that this synthesis promotes and stimulates new interdisciplinary research efforts necessary to close the many existing gaps about the causes and consequences of insect flight evolution.

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Descending control of motor sequences in

Cited by 7 publications

References 83 publications

Comparative connectomics of the descending and ascending neurons of theDrosophilanervous system: stereotypy and sexual dimorphism

Comparative connectomics of the descending and ascending neurons of theDrosophilanervous system: stereotypy and sexual dimorphism

Descending networks transform command signals into population motor control

Insect Flight: State of the Field and Future Directions

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