Flygenvectors: The spatial and temporal structure of neural activity across the fly brain

Abstract

What are the spatial and temporal scales of brain-wide neuronal activity, and how do activities at different scales interact? We used SCAPE microscopy to image a large fraction of the central brain of adult Drosophila melanogaster with high spatiotemporal resolution while flies engaged in a variety of behaviors, including running, grooming and flailing. This revealed neural representations of behavior on multiple spatial and temporal scales. The activity of most neurons across the brain correlated (or, in some cases, anticorrelated) with running and flailing over timescales that ranged from seconds to almost a minute. Grooming elicited a much weaker global response. Although these behaviors accounted for a large fraction of neural activity, residual activity not directly correlated with behavior was high dimensional. Many dimensions of the residual activity reflect the activity of small clusters of spatially organized neurons that may correspond to genetically defined cell types. These clusters participate in the global dynamics, indicating that neural activity reflects a combination of local and broadly distributed components. This suggests that microcircuits with highly specified functions are provided with knowledge of the larger context in which they operate, conferring a useful balance of specificity and flexibility.

Mapping the Neural Dynamics of Locomotion across the Drosophila Brain

“…In addition, brain-wide signatures of neural activity associated with swimming and crawling have been measured in larval zebrafish, larval Drosophila , and C. elegans (Ahrens et al, 2012; Chen et al, 2018; Dunn et al, 2016; Hallinen et al, 2021; Kato et al, 2015; Kim et al, 2017; Mu et al, 2020; Naumann et al, 2016; Nguyena et al, 2015; Susoy et al, 2021). Moreover, recent work has described whole-brain imaging techniques in adult flies in the context of state dependent changes in activity and metabolism (Aimon et al, 2019; Mann et al, 2017; Mann et al, 2021; Schaffer et al, 2021; Tainton-Heap et al, 2021), as well as sensory evoked responses (Harris et al, 2015; Münch et al, 2021; Pacheco et al, 2021). Given the accumulating evidence across species for widespread distribution of motor signatures, directly measuring this topography is likely to provide insight into how the brain produces walking behavior.…”

Combined patterns of activity of major neuronal classes underpin a global change in brain state during spontaneous and forced walk inDrosophila

“…We prepared the flies as described in detail in 14 . Briefly, we fixed a fly to a custom-designed 3D printed holder, so as to allow access to the whole posterior side of the head while the legs were free to move.…”

“…To image wholebrain activity during spontaneous behavior, we fixed the fly's head to a holder and opened the posterior head capsule while leaving the legs free to move 14 (Fig. 1a).…”

Neural Circuits Underlying Behavioral Flexibility: Insights From Drosophila

“…Indeed, locomotor activity seems to be one of the most critical behavioral states an organism needs to account for. Large-scale imaging studies have found that walking state increases global brain activity, suggesting that this state signal is transmitted to many different circuits with different functions (Aimon et al, 2019 ; Schaffer et al, 2021 ). One function of this state-dependent modulation may be to suppress behaviors that should not be expressed during walking.…”