Biology subjects

Noebauer, T.

Publications and source records attributed to Noebauer, T..

4 recordsLinked to original sources

bioRxiv2026

Large-scale volumetric two-photon calcium imaging enables cellular-resolution mesoscopic mapping of marmoset cortical areas

Primate neocortex is organized into functionally defined domains. Understanding how the functional organization within each domain emerges from single-cell tuning properties has been hampered by the lack of imaging tools that can capture large-scale activity at different depths of the scattering primate brain at cellular resolution and physiological timescales. Here, we demonstrate mesoscopic and volumetric cellular-resolution calcium imaging of entire cortical areas in the marmoset brain at multi-Hertz rates by combining fluorescence lifetime-limited temporally multiplexed two-photon recording based on Light Beads Microscopy (LBM) with optimized calcium indicator targeting. Using this approach, we perform volumetric recording of neuronal population activity within cortical volumes spanning up to 4 x 4 x 0.3 mm3 capturing the simultaneous activity of over 96,000 cells, including more than 46,000 stimulus-responsive neurons. In auditory cortex, we found fine-grain heterogeneous tuning of individual neurons to frequencies within broader tonotopic gradients. In the middle temporal area (MT) we found direction tuning along functional continua rather than discrete categories, encompassing uni-, bi-, and pandirectional tuning, where cells with similar tuning tend to cluster. Tuning direction follows a columnar organization with a lateral periodicity of [~]500 {micro}m and low variability across depth. Columns are organized by a pinwheel structure. Noise correlations between cells, revealing functional interactions, decay isotropically and monotonically with distance but remain significant even at lateral distances exceeding 3 mm and thus the scale of multiple columns. Together, these discoveries reveal the need for neurotechnologies bridging scales from single cells to multi-columnar systems. The technological advancements open the door for future large-scale, cellular-resolution investigations of functional organization and population dynamics across entire cortical areas in the primate brain.

neuroscience↗

bioRxiv2024

A Systematically Optimized Miniaturized Mesoscope (SOMM) for large-scale calcium imaging in freely moving mice

Understanding how neuronal dynamics gives rise to ethologically relevant behavior requires recording of neuronal population activity via technologies that are compatible with unconstrained animal behavior. However, realizations of cellular resolution head-mounted microscopes for mice have been based on conventional microscope designs that feature various forms of ad-hoc miniaturization and weight reduction measures necessary for compatibility with the weight-limits for free animal behavior. As a result, they have typically remained limited to a small field of view (FOV) or low resolution, a shallow depth range and often remain susceptible to motion-induced artifacts. Here, we present a systematically optimized miniaturized mesoscope (SOMM), a widefield, head-mounted fluorescent mesoscope based on a principled optimization approach that allows for mesoscale, cellular resolution imaging of neuroactivity while offering robustness against motion-induced artifacts. This is achieved by co-optimization of a compact diffractive optical element and the associated computational algorithm under form-factor and weight constraints while maximizing the obtainable FOV, depth of field (DOF), and resolution. SOMM enables recordings of neuronal population activity at up to 16 Hz within a FOV of 3.6 x 3.6 mm2 in the cortex of freely moving mice while featuring 4-{micro}m resolution, a DOF of 300 {micro}m at a weight of less than 2.5 g. We show SOMMs performance of recording large-scale neuronal population activity during social interactions, during conditioning-type experiments and by investigating neurovascular coupling using dual-color imaging.

neuroscience↗

bioRxiv2019

Cerebellar neurodynamics during motor planning predict decision timing and outcome on single-trial level

The neuronal basis of goal-directed behavior requires interaction of multiple separated brain regions. How subcortical regions and their interactions with brain-wide activity are involved in action selection is less understood. We have investigated this question by developing an assay based on whole-brain volumetric calcium imaging using light-field microscopy combined with an operant-conditioning task in larval zebrafish. We find global and recurring dynamics of brain states to exhibit pre-motor bifurcations towards mutually exclusive decision outcomes which arises from a spatially distributed network. Within this network the cerebellum shows a particularly strong pre-motor activity, predictive of both the timing and outcome of behavior up to [~]10 seconds before movement initiation. Furthermore, on the single-trial level, decision directions can be inferred from the difference neuroactivity between the ipsilateral and contralateral hemispheres, while the decision time can be quantitatively predicted by the rate of bi-hemispheric population ramping activity. Our results point towards a cognitive role of the cerebellum and its importance in motor planning.

neuroscience↗

bioRxiv2017

Video rate volumetric Ca2+ imaging across cortical layersusing Seeded Iterative Demixing (SID) microscopy

Light-field microscopy (LFM) is a scalable approach for volumetric Ca2+ imaging with the highest volumetric acquisition rates (up to 100 Hz). While this has enabled high-speed whole-brain Ca2+ imaging in small semi-transparent specimen, tissue scattering has limited its application in the rodent brain. Here we introduce Seeded Iterative Demixing (SID), a computational source extraction technique that extends LFM to the scattering mammalian cortex. Using GCaMP-expressing mice we demonstrate SIDs ability to capture neuronal dynamics in vivo within a volume of 900x900x260m located as deep as 380 m in the mouse cortex and hippocampus at 30 Hz volume rate while faithfully discriminating signals from neurons as close as 20 m, at three orders of magnitude reduced computational cost. The simplicity and scalability of LFM, coupled with the performance of SID opens up a range of new applications including closed-loop experiments and is expected to propel its wide dissemination within the neuroscience community.

neuroscience↗