Browsing by Author "Dunn, Timothy W"

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    Brain-wide mapping of neural activity controlling zebrafish exploratory locomotion.
    (eLife, 2016-03-22) Dunn, Timothy W; Mu, Yu; Narayan, Sujatha; Randlett, Owen; Naumann, Eva A; Naumann, Eva A; Yang, Chao-Tsung; Schier, Alexander F; Schier, Alexander F; Freeman, Jeremy; Engert, Florian; Ahrens, Misha B
    In the absence of salient sensory cues to guide behavior, animals must still execute sequences of motor actions in order to forage and explore. How such successive motor actions are coordinated to form global locomotion trajectories is unknown. We mapped the structure of larval zebrafish swim trajectories in homogeneous environments and found that trajectories were characterized by alternating sequences of repeated turns to the left and to the right. Using whole-brain light-sheet imaging, we identified activity relating to the behavior in specific neural populations that we termed the anterior rhombencephalic turning region (ARTR). ARTR perturbations biased swim direction and reduced the dependence of turn direction on turn history, indicating that the ARTR is part of a network generating the temporal correlations in turn direction. We also find suggestive evidence for ARTR mutual inhibition and ARTR projections to premotor neurons. Finally, simulations suggest the observed turn sequences may underlie efficient exploration of local environments.
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    Gigapixel imaging with a novel multi-camera array microscope.
    (eLife, 2022-12) Thomson, Eric E; Harfouche, Mark; Kim, Kanghyun; Konda, Pavan C; Seitz, Catherine W; Cooke, Colin; Xu, Shiqi; Jacobs, Whitney S; Blazing, Robin; Chen, Yang; Sharma, Sunanda; Dunn, Timothy W; Park, Jaehee; Horstmeyer, Roarke W; Naumann, Eva A
    The dynamics of living organisms are organized across many spatial scales. However, current cost-effective imaging systems can measure only a subset of these scales at once. We have created a scalable multi-camera array microscope (MCAM) that enables comprehensive high-resolution recording from multiple spatial scales simultaneously, ranging from structures that approach the cellular scale to large-group behavioral dynamics. By collecting data from up to 96 cameras, we computationally generate gigapixel-scale images and movies with a field of view over hundreds of square centimeters at an optical resolution of 18 µm. This allows us to observe the behavior and fine anatomical features of numerous freely moving model organisms on multiple spatial scales, including larval zebrafish, fruit flies, nematodes, carpenter ants, and slime mold. Further, the MCAM architecture allows stereoscopic tracking of the z-position of organisms using the overlapping field of view from adjacent cameras. Overall, by removing the bottlenecks imposed by single-camera image acquisition systems, the MCAM provides a powerful platform for investigating detailed biological features and behavioral processes of small model organisms across a wide range of spatial scales.