Tag Archives: Microscopy

Matlab code for control of a resonant scanning microscope

For control of resonant scanning 2P microscopes, my host lab uses a software that I have written in Matlab. Due to some coincidences, the software is based on Scanimage 4.2, a version developed few years ago for an interface with a Thorlabs scope and Thorlabs … Continue reading

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Preamplifier bandwidth & two ways of counting photons

For two-photon point scanning microscopy, the excitation laser is typically pulsing at a repetition rate of 80 MHz, that is one pulse each 12.5 ns. To avoid aliasing, it was suggested to synchronize the sampling clock to laser pulses. For this, it is important … Continue reading

Posted in Calcium Imaging, Imaging, Microscopy | Tagged , , , | 2 Comments

Large field of view microscopes for mouse brain imaging

For typical confocal or two-photon microscopes that maintain (sub)cellular resolution, a high-magnification objective is needed (typically 16x, 20x or 25x). This in turn limits the field of view (FOV) to ⌀ 1.0-1.5 mm. For imaging in the mouse brain cortex, which is … Continue reading

Posted in Calcium Imaging, Imaging, Microscopy | Tagged , , | 5 Comments

Fast z-scanning using a voice coil motor

We just published a paper on fast remote z-scanning using a voice coil motor. For 2P calcium imaging. It’s a nice paper with some interesting technical details. The starting point was the remote z-scanning scheme used by Botcherby et al. (2012) from … Continue reading

Posted in Calcium Imaging, Imaging, Microscopy, Neuronal activity | Tagged , , , | 2 Comments

Modulating laser intensity on multiple timescales (x, y and z)

In point-scanning microscopy and especially when using resonant scanners, the intensity of the beam is typically modulated using a Pockels cell. For resonant scanning, the dwell time per micrometer is not constant along the scanned line, and one wants either to … Continue reading

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Undistort/unwarp images for resonant scanning microscopy

For image acquisition using a resonant scanning microscope, one of the image axes is scanned non-linearly, following the natural sinusoidal movements of the resonant scanner. This leads to a distortion of the acquired images, unless a online correction algorithm or … Continue reading

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Point spread functions

One way to characterize the quality of one’s microscope is to measure the point spread function (PSF), that is the image that is created by a point source  (which can be a fluorescent bead smaller than the expected size of the … Continue reading

Posted in Microscopy | Tagged , , | 3 Comments