Shown at -20° Rotation
Ø5 mm FOV Captures Multiple Brain Regions
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Random Access Scanning
The mesoscope creates high-speed images following user-defined scan patterns that translate the field of view laterally and axially.
Several images and the video on this webpage are taken from https://elifesciences.org/content/5/e14472/
Range of Motion
Thorlabs' Mesoscope provides subcellular resolution over an exceptionally large Ø5 mm field of view. As shown in the schematic at the top of the webpage, it enables in vivo functional imaging of spatially separated brain regions operating in concert. When imaging across user-defined, non-contiguous regions of interest within the field, near-video frame rates are possible, as demonstrated in the video to the right. A lateral scan unit, in conjunction with a built-in remote focusing mirror, enables both lateral and axial translation of the field during the measurement.
Developed and commercialized in collaboration with Karel Svoboda's research laboratory at HHMI's Janelia Research Campus, the mesoscope is designed for large-area functional imaging of individual neurons. It contains many optical systems that are specifically optimized to work together, including the built-in remote focusing mirror, which translates the focal plane over a 1 mm range; the lateral scan unit, which comprises virtually conjugated mirrors and a resonant scanner; a multi-jointed periscope that maintains the laser alignment over the entire range of motion; and the objective itself.
Since the study of awake, behaving specimens benefits from large working spaces, the mesoscope's enclosure leaves the surface of the optical workstation free for the experimental apparatus. In addition, we incorporated motion control systems directly into the mesoscope's body, permitting the specimen to remain fixed on the optical workstation as the mesoscope moves. The mesoscope body allows -20° to +20° rotation for the objective, as well as 2" of fine X motion, 6" of fine Y motion, and 2" of fine Z motion; just as with Thorlabs' Bergamo® II multiphoton microscope, X, Y, and Z rotate along with the objective.
The included objective is specifically designed for use with the mesoscope and provides large excitation and collection NAs of 0.6 and 1.0, respectively. Fast fine focusing adjustments are enabled by the lightweight remote focusing mirror, which translates the focal plane without moving the objective. The scan path wavelength range of 900 - 1070 nm was chosen for optimal two-photon excitation of GFP and red fluorescent proteins, and is compatible with any tunable Ti:sapphire laser designed for multiphoton microscopy, such as Thorlabs' Tiberius® laser.
2p-RAM: Two-Photon Random Access Mesoscope
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The mesoscope allows a user-defined number of regions of interest to be tracked within a single scan.
(Courtesy of Karel Svoboda, Janelia Research Campus, Virginia, USA.)