Unbounded scaling of dimensionality with neuron number

Optical Neurotechnology
Our paper entitled “Simultaneous, cortex-wide and cellular-resolution neuronal population dynamics reveal an unbounded scaling of dimensionality with neuron number” has been published in Neuron. The brain’s remarkable properties arise from collective activity of millions of neurons. Widespread application of dimensionality reduction to multi-neuron recordings implies that neural dynamics can be approximated by low-dimensional “latent” signals reflecting neural computations. However, what would be the biological utility of such a redundant and metabolically costly encoding scheme and what is the appropriate resolution and scale of neural recording to understand brain function? Imaging the activity of one million neurons at cellular resolution and near-simultaneously across mouse cortex, we demonstrate an unbounded scaling of dimensionality with neuron number. While half of the neural variance lies within sixteen behavior-related dimensions, we find this unbounded scaling…
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Mesoscale volumetric light-field (MesoLF) imaging of neuroactivity across cortical areas at 18 Hz

Optical Neurotechnology, Research
Our paper entitled “Mesoscale volumetric light field (MesoLF) imaging of neuroactivity across cortical areas at 18 Hz” has been published in Nature Methods. We present a modular, mesoscale light field (MesoLF) imaging hardware and software solution that allows recording from thousands of neurons within volumes of ⌀4 × 0.2 mm, located at up to 350 µm depth in the mouse cortex, at 18 volumes per second (Video 1). Using our optical design and computational approach we show recording of ~10,000 neurons across multiple cortical areas in mice using workstation-grade computing resources. Video 1 | Animated perspective rendering of neuron positions and calcium activity recorded using MesoLF in mouse cortex. Field of view: ⌀4000 × 200 µm. Depth range: 0–200 µm. Recording frame rate: 18 Hz. Real-time recording duration: 405 s. Playback speed-up: 25×. Labelling construct: AAV9-TRE3-2xsomaGCaMP7f. Information…
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High-Speed, Cortex-Wide Volumetric Recording of Neuroactivity at Cellular Resolution Using Light Beads Microscopy

Optical Neurotechnology, Research
Our paper entitled “High-Speed, Cortex-Wide Volumetric Recording of Neuroactivity at Cellular Resolution using Light Beads Microscopy” has been published in Nature Methods. This work details our new method Light Beads Microscopy (LBM) which makes use of a column of “Light Beads” – individual beams which are distinguishable in time and focus to different depths in the sample (Fig. 1a)  – in order to record from the entire depth range of a given volume within the dead time between consecutive pulses from our excitation laser. By combining LBM with a commercial mesoscope, we can image mesoscale and volumetric fields of view (FOVs) at the same rate that a conventional mesoscope records a single plane. As a result, LBM gives optical access to the activity of cortex-wide volumes, allowing recording of up…
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