Walking elicits global brain activity in Drosophila

Movement and behavioral state influence perception, and a stimulus can elicit opposite behavioral actions depending on whether the animal is moving toward or away from it. Here, we use fast wholebrain lightfield imaging in adult Drosophila melanogaster to analyze the relationship between movement and neuronal activity. Using pan-neuronal calcium imaging, we observe brainwide neuronal activity that tightly correlated with spontaneous bouts of movement. Imaging of specific sets of neurons across the brain reveals that both excitatory and inhibitory as well as different types of neuromodulatory neurons are active during walk inconsistent with a reduction of inhibition on neuronal activity. While most neuron types are activated at walk-onset, serotonergic neurons show more complex patterns of activity with neurons in several brain regions being inhibited during walk. Using available anatomical data, we map forward running and turning-induced activity onto different brain subregions and sometimes individual neurons. Moreover, we find that spontaneous walk and forced walk elicit highly similar wholebrain activity suggesting that a large part of the observed activity corresponds to walk itself rather than its initiation by higher brain centers. Based on our data, we conclude that movement and movement-related sensory feedback signals originating in the ventral nerve cord induce wide-spread activity in the brain allowing the integration of behavioral state into most or all brain processes. ### Competing Interest Statement The authors have declared no competing interest.