Two brain pathways initiate distinct forward walking programs inDrosophila

Abstract

An animal at rest or engaged in stationary behaviors can instantaneously initiate goaldirected walking. How descending brain inputs trigger rapid transitions from a non-walking state to an appropriate walking state is unclear. Here, we identify two specific neuronal classes in the Drosophila brain that drive two distinct forward walking programs in a context-specific manner.The first class, named P9, consists of descending neurons that drive forward walking with ipsilateral turning. P9 receives inputs from central courtship-promoting neurons and visual projection neurons and is necessary for a male to track a female during courtship. The second class comprises novel, higher order neurons, named BPN, that drives straight, forward walking. BPN is required for high velocity walking and is active during long, fast, straight walking bouts. Thus, this study reveals separate brain pathways for object-directed steering and fast straight walking, providing insight into how the brain initiates different walking programs.Raw and processed data along with custom Matlab analysis scripts will be made available upon request. Design files for custom parts will be available upon request.Ache, J.M., Haupt, S.S., and Dürr, V. (2015). A direct descending pathway informing locomotor networks about tactile sensor movement.

Object-Displacement-Sensitive Visual Neurons Drive Freezing in Drosophila

“…However, we did not observe any significant reduction of the freezing by silencing DNp35 (Figure S2L). We also saw no effect of silencing DNp09, a descending neuron that is implicated in loom-induced freezing [68] and forward walking [29] and that is functionally connected to LC11 [29] (Figure S2K). These results imply that, unlike some VPNs that are directly presynaptic to descending neurons (e.g., LPLC2/LC4 to the giant fiber motor neuron [70]), outputs of LC11 undergo more nuanced computation in downstream circuitry before reaching command neurons.…”

“…For instance, experiments that activated LC11 using optogenetic methods did not observe obvious behavioral phenotypes [19]. One study found that silencing LC11 in male flies compromised tracking of females [29], while another did not [5]. One study has also reported that silencing LC11 impairs a reduction of minute time-scale freezing in response to looming stimuli when flies are in groups [30].…”

Spatiotemporally precise optogenetic activation of sensory neurons in freely walking Drosophila

“…Early studies in Drosophila used gynandromorphs to create bilaterally differentiated flies Benzer, 1970, 1972). Alternatively, sparse, stochastic expression patterns can be generated across a population, which then can be screened to determine the expression patterns of individual specimens (Bidaye et al, 2019;Lee and Luo, 1989;Ribeiro et al, 2018;Wu et al, 2016;Xu and Rubin, 1993). Both approaches rely on time-intensive techniques.…”

Binocular Mirror-Symmetric Microsaccadic Sampling EnablesDrosophilaHyperacute 3D-Vision

“…S57.). Both neuron-types have been shown to play a role in the circuitry controlling courtship behavior (102,103). The next most common neuron, IB011, displays some structural similarities to LC14 neurons (104).…”