Venkatakaushik Voleti

High-speed 3D imaging of cellular activity in the brain using axially-extended beams and light sheets

As optical reporters and modulators of cellular activity have become increasingly sophisticated, the amount that can be learned about the brain via high-speed cellular imaging has increased dramatically. However, despite fervent innovation, point-scanning microscopy is facing a fundamental limit in achievable 3D imaging speeds and fields of view. A range of alternative approaches are emerging, some of which are moving away from point-scanning to use axially-extended beams or sheets of light, for example swept confocally aligned planar excitation (SCAPE) microscopy. These methods are proving effective for high-speed volumetric imaging of the nervous system of small organisms such as Drosophila (fruit fly) and D. Rerio (Zebrafish), and are showing promise for imaging activity in the living mammalian brain using both single and two-photon excitation. This article describes these approaches and presents a simple model that demonstrates key advantages of axially-extended illumination over point-scanning strategies for high-speed volumetric imaging, including longer integration times per voxel, improved photon efficiency and reduced photodamage.

Whole-volume clustering of time series data from zebrafish brain calcium images via mixture modeling.

Calcium is a ubiquitous messenger in neural signaling events. An increasing number of techniques are enabling visualization of neurological activity in animal models via luminescent proteins that bind to calcium ions. These techniques generate large volumes of spatially correlated time series. A model-based functional data analysis methodology via Gaussian mixtures is suggested for the clustering of data from such visualizations is proposed. The methodology is theoretically justified and a computationally efficient approach to estimation is suggested. An example analysis of a zebrafish imaging experiment is presented.

Two-photon Swept Confocally Aligned Planar Excitation Microscopy (2P-SCAPE)

We report our recent progress on two-photon implementations of Swept Confocally Aligned Planar Excitation (SCAPE) microscopy for high-speed 3D in vivo imaging of scattering biological samples including mammalian brain.

Design of a Second Generation Laser Scanning Intersecting Plane Tomography (LSIPT) System

We present recent development of a single-objective, high-speed volumetric microscopy method, including optimization via a comprehensive ray tracing model. L-SIPT is capable of in-vivo imaging of intact rodent brain and transgenic drosophila at >30 VPS.