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1/ New in @sciencemagazine w/ @KarlDeisseroth lab: science.sciencemag.org/content/early/…: new opsin + multi-photon holography to image ~4000 cells in 3D volumes over 5 cortical layers while also stimulating ~50 neurons to directly drive visual percepts; data analysis and theory reveal… 
2/ that visual cortex operates in a highly sensitive critically excitable regime in which stimulating a tiny subset of ~20 cells with similar orientation tuning is sufficient to both selectively recruit a large fraction of similarly responding cells and drive a specific percept
3/ theoretical analysis reveals this very low threshold, for the ignition of both large cell assemblies and perception, is almost as low as it can possibly be while still optimally avoiding false positive percepts driven by fluctuations in spontaneous activity
4/ a mean field analysis suggests a critically excitable operating regime for V1 in which large assemblies of order N similarly tuned neurons can be recruited by stimulating a tiny subset of only order square root of N neurons, thereby enabling strikingly high sensitivity
5/ overall this combo of all optical read-write technology, data analysis, and theory could hopefully lead to many new theory/exp collaborations where we read the language of the brain, modify it, write it back in, and see how the brain responds, in order to learn its secrets
6/ None of this possible without an amazing team working seamlessly across the @KarlDeisseroth lab and my lab with excellent experiments and technology dev by @JimMarshel @Yoon_Seok_Kim Sean Quirin, data analysis by @machado_ta and theory and sim by @kadmonj and Brandon Benson
