Tag: two-photon

PMT power supply

I was cleaning house a bit, and among my old files I found this, which might be worth sharing. Years ago I made a centralized power supply for a custom 2-photon imaging system I built. There were two epi detectors (for red & green fluorescence) and three trans detectors (red, green, and IR-based “DIC-like Dodt”

Analysis algorithms: performance quantification and ground truth

We recently tweeted about a preprint from Eftychios A Pnevmatikakis and Andrea Giovannucci (code). The preprint is on motion correction for calcium imaging data. It is a nice quick read and discusses earlier work in the area. (That’s Eftychios of constrained-non-negative-matrix-factorization-for-calcium-imaging-analysis fame). Marius Pachitariu recognized the algorithm as very similar to one that he uses

Tons of 2p spectra – twophotondyes.com

  Daniel Fiole is curating a nice resource for 2p cross sections: twophotondyes.com There’s a lot here. It’s not just dyes, he has links for fluorescent proteins as well, and there’s 3p data linked to as well: Prior posts on 2p cross sections:  

Ripple noise on PMTs in 2-photon imaging – Part 2

The recent post on ripple noise generated some comments and additional discussion. Go check out the comments on that post. For example, Peter Rupprecht shared some snapshots an oscilloscope display showing the signal from the BNC connector at the back of the laser, in the presence of this ripple noise. The ripple is seen when

Ripple noise on PMTs in 2-photon imaging

Andrew Lim wrote in to discuss strategies on dealing with ripple noise in 2-photon imaging systems, particularly when using resonant scanners. He writes: This isn’t so much a tip as a problem with resonant two-photon scopes that several people have told me they also have but I haven’t seen a solution for (other people apparently

Postdoc position with Duguid in Edinburgh

A world-class in vivo patch clamp electrophysiologist, Ian Duguid, is recruiting to his lab. Ian provides excellent training, and his lab is in a tremendous setting: Edinburgh. Ian’s also one of the current leaders of the famous CSHL Ion Channels course. By the way, his web site also has some interesting machine drawings and other

Constrained non-negative matrix factorization for calcium imaging data analysis

I tweeted about this last fall. This is the best algorithm I’ve seen for segmenting and extracting time course from calcium imaging data. Eftychios Pnevmatikakis developed the code in Liam Paninski’s lab. The work is reported in a pair of papers in Neuron, and the code is freely available (links below). The source separation works

CANDLE-J for denoising 2p data

Collaborative Approach for eNhanced Denoising under Low-light Excitation, or CANDLE, is a denoising algorithm specialized for the type of images that are acquired in 2-photon imaging applications. There’s code for both ImageJ and MATLAB available at that link. Here’s a write up on it. The raw images are on the left, and the denoised (via

Upconversion: NIR in, vis out

Compared to visible (vis) light, near infrared (NIR) wavelength scatters less and is less absorbed in brain tissue. If your fluorescent target absorbs vis light, then one way to use NIR is to flood the area with molecules that will absorb NIR and emit vis light. The process is called “upconversion“, since it is in

Imaging Course at Max Planck Florida

The Max Planck Florida Institute for Neuroscience is holding an imaging course Jan 11-20, 2016. They have a really excellent line up of lecturers. A range of topics will be covered: two-photon imaging, FLIM, FRET, endoscopy, uncaging, optogenetics, SPIM, image analysis, instrumentation (alignment, system design), … Applications are due in a few days, Nov. 17.

FocusStack and StimServer for MATLAB

Dylan Muir and Bjorn Kampa created some MATLAB code for two-photon calcium imaging experiments. First up is FocusStack, which provides a suite of analysis tools. Next up is StimServer, which coordinates visual stimulus generation and presentation. The paper is open access. In particular, Dylan’s MATLAB functions MappedTensor and TIFFStack are worth checking out. Both provide

SIMA update – for 2p calcium imaging

SIMA has recently been updated (here’s the original Labrigger post): From the SIMA team: We have recently released updated versions of the SIMA & ROI Buddy tools for analysis of calcium imaging data (motion correction, segmentation, registration of ROIs across different imaging sessions, signal extraction). These new versions now support 3D datasets, allowing for analysis

Field of view = 3.5 mm with cellular resolution

In this preprint, Stirman et al. report achieving a 3.5 mm field of view with 2-photon excitation with cellular resolution. The design involves custom scan optics and a custom objective built in the SLAB. It’s an air immersion objective with about a 9.5 mm working distance. Rapid dissemination is a priority. If you’re interested, contact

A Canadian open source two-photon microscope system

This open source two-photon microscope system is adaptable for both slice (with substage detection) and in vivo experiments, and is built with largely COTS parts. The paper is a very nice resource. See also, designs shared by the Svoboda lab

Resonant scanning with ScanImage 5

ScanImage 5 supports resonant scanning with a wide range of hardware. So custom rigs can add resonant scanning pretty easily, while sticking with ScanImage for acquisition. It takes about $10,000 worth of electronics from National Instruments. In addition, you’ll need the resonant and galvo scanners themselves. From Cambridge, resonant scanners are under $2000, and conventional