Directional elements: the preprints are out! Congratulations to our amazing team linked here: biorxiv.org/content/10.64898… biorxiv.org/content/10.64898… biorxiv.org/content/10.64898… We screened for principles governing global brain dynamics by developing a set of new methods: 1) conformal immersion microscopy for recording high-speed/high-resolution neural activity across dorsal cortex; 2) unbiased computational screening of brain-spanning activity for fast directionally-propagating spatiotemporal elements; and 3) novel genetically-encoded voltage sensing integrated with designed spectrally-compatible opsins (derived from our channelrhodopsin structure work) for systematic causal testing. This unbiased screening/testing approach (which we show is applicable either to voltage or calcium imaging) allowed discovery and functional validation of a surprisingly well-defined set of directional elements that generalized across cell types and frequencies. The ability to work over long timescales at high speeds and with broad scope, anchored in optogenetic causal testing, unveiled rich spatiotemporal structure that was remarkably tractable. From the perspective of natural brain function, the directional elements were found to be behaviorally relevant and robust to diverse perturbations; however, we also found specific conditions allowing elemental incidence and boundaries to be selectively modulated, which may provide translational as well as basic-science insight... I'm so grateful to all our collaborators, and honored to work with all the outstanding students, postdocs, and staff who worked together to develop and apply this approach...