Kaspar Podgorski

CT-inspired two-photon lets us record glutamate activity from hundreds of synapses at a time, at >1000 Hz. Really happy to share this, and there's more to come! rdcu.be/bMihg

@Nick_from_Texas @AllenInstitute @abhi_aggarwal1 These are spontaneous release events in TTX (called 'minis'). They occur randomly. Without TTX, we see larger, synchronous, often wave-like patterns. Example data available for download with the 2023 iGluSnFR3 paper. Our newest indicators, iGluSnFR4, are now out on bioRxiv!

@AllenInstitute @abhi_aggarwal1 @PodgorskiLab I'm surprised the neuron activations don't occur in waves. Was this visualization built using data?

The fireworks in your mind. 🧠✨ This sparkling video shows the neurotransmitter glutamate being released into synapses, made possible by an indicator developed by @abhi_aggarwal1, @PodgorskiLab, and team. #HappyNewYear #NYE

Meet MagLOV: an engineered protein that responds STRONGLY to magnetic fields. This is a fluorescence timelapse of MagLOV in E. coli. We're waving a (small) magnet under the plate. Can you tell where the magnet is? Want some? It's on Addgene now! addgene.org/219957/

@WikiZong @voigtvision @timdweber @Thorlabs @brunopichler @Labrigger @ptrrupprecht @TeleVueOptics #67-251 Edmund

@PodgorskiLab @voigtvision @timdweber @Thorlabs @brunopichler @Labrigger @ptrrupprecht @TeleVueOptics Curious about which lens did you use as the second condenser lens.

Dear #Microscopy hivemind: What's the current take on using the @Thorlabs Silicon Photomultipliers for multiphoton imaging? Has anybody played with them? Are people happy with the dark counts? @PodgorskiLab @brunopichler @Labrigger @ptrrupprecht thorlabs.com/newgrouppage9.…

@voigtvision @timdweber @Thorlabs @brunopichler @Labrigger @ptrrupprecht @TeleVueOptics I don't- that's a great point and definitely worth knowing for the sensor size tradeoff!

@PodgorskiLab @timdweber @Thorlabs @brunopichler @Labrigger @ptrrupprecht @TeleVueOptics 👍 Do you know what the maximum acceptance cones are?

@voigtvision @timdweber @Thorlabs @brunopichler @Labrigger @ptrrupprecht @TeleVueOptics In our SLAP2 microscope, we get efficient collection with a single-element condenser as the second element of the detection path telescope. The 3mm active area is just big enough for the shortest FL singlet condensers in the Edmund catalog.

@timdweber @Thorlabs @PodgorskiLab @brunopichler @Labrigger @ptrrupprecht @TeleVueOptics The Ethos 13 mm has 100 degrees apparent FOV and an eye relief of 15 mm and costs approx. $650 - lots of money for an amateur astronomer, but not that much for a high-end #microscope But: It is huge: scopereviews.com/Ethos.html

@hod_dana @voigtvision @Thorlabs @brunopichler @Labrigger @ptrrupprecht *digitizer limits

@voigtvision @Thorlabs @PodgorskiLab @brunopichler @Labrigger @ptrrupprecht What I was told by their rep is that they should have a 6mm aperture version soon. May be worth waiting for it.

@hod_dana @voigtvision @Thorlabs @brunopichler @Labrigger @ptrrupprecht Overall, excited. 3mm has lower dark counts than 6mm would, and it's not too hard to keep all your light in the 3mm. 6mm will be a better drop-in. Main worry is that they will underperform the SiPMs impressive dynamic range at high gain because of amplifier rails/detector limits

I am thrilled to share my first bio paper ever in @AdamEzraCohen lab with super important contributions from @rhodamine110 lab! We asked the question: How do neurons compute? We focused on L2/3 neurons. Come for the science, stay for the videos! (1/17) twitter.com/biorxiv_neursc…

@KentaM_Hagihara Not to bias the poll, but what are the advantages of AAV9 over PhP.eB?

Results translatability, stable/less-variable expression levels, tropism, etc, many factors to be considered. Rationale, comments, suggestions, and questions are all appreciated. Share your expertise and let's benchmark these sensors side-by-side in a standardized manner!

We @AllenInstitute for NeurDyn-Ophys are gearing up to launch a platform for in vivo testing of genetic NM/NT/Voltage indicators. We want your opinion on the most suitable AAV serotype to deliver sensors to be tested. Which serotype do you think would be the best fit?

@Notas_medicina @AllenInstitute @abhi_aggarwal1 @naturemethods This point can be a bit contentious- protons are more abundant... but the most abundant NT molecule

Take a break from doomscrolling and relax with this dazzling video of the neurotransmitter glutamate being released into synapses, made possible by a new indicator developed by @abhi_aggarwal1, @PodgorskiLab, & team. Out in @NatureMethods: nature.com/articles/s4159… #NeuroTwitter

🎉 Thrilled to share 4 yrs of hard work: iAspSnFR preprint at tinyurl.com/38ve4vh9 🔬 GFP-based aspartate sensor, engineered via deep mutational scanning, tested in HEK293 cells. Highly specific for intracellular aspartate! #iAspSnFR #biosensor #aspartate

@JimJohnsonSci @abhi_aggarwal1 @HHMIJanelia @AllenInstitute Yes! @abhi_aggarwal1 made a super-low affinity version and we are working with collaborators to apply it

@abhi_aggarwal1 @PodgorskiLab @HHMIJanelia @AllenInstitute Can these be flipped around and used to look at metabolism within cells?

iGluSnFR3 is published! Check it out⬇️ nature.com/articles/s4159… We made a new glutamate indicator with improved sensitivity, kinetics & localization for imaging synaptic transmission. This is #iGluSnFR3 in action detecting minis w/ TTX. @PodgorskiLab @HHMIJanelia @AllenInstitute

@HasanU_JP @abhi_aggarwal1 @HHMIJanelia @AllenInstitute I saw an abstract (I believe from Torok group) about development of an ultrafast iGluSnFR3. Axonal localization was achieved by Kim et al (doi.org/10.1523/JNEURO…). One of our iGluSnFR4 variants is *extremely* fast as well, but still to be tested in vivo. Stay tuned!

@abhi_aggarwal1 @PodgorskiLab @HHMIJanelia @AllenInstitute Hey! Great to see it published! Quick Q: is there any fast/ultrafast version of iGluSnFR3 available/coming? Quick Q2: any updates on axonal expression? (It works great in primary culture but we have some difficulty in schaffer collaterals in slice)

@AndrewHires @abhi_aggarwal1 @HHMIJanelia @AllenInstitute It's a tricky measurement to make. We haven't gone deep on it. Looking at amplitudes, some sites are very quantal, while others are not. There's been some nice work from @OertnerLab with older iGluSnFRs, would be exciting to see with iGluSnFR3.

@abhi_aggarwal1 @PodgorskiLab @HHMIJanelia @AllenInstitute Are you able to see any direct evidence for full fusion vs kiss-and-run release from single event spatiotemporal dynamics?

Our group is looking for a Research Associate interested in helping test new fluorescent indicators in vivo. Fun team. Relocation support to Seattle. Know anyone? #Divisions" target="_blank" rel="nofollow noopener">alleninstitute.org/careers/#Divis…

Folks, first paper of our lab is out!! We discovered that a couple of trans-synaptic proteins, LGI1 and ADAM23, are acutely translocated to the synaptic surface during firing! This controls their abundance at clefts, impacting locally glutamate release. biorxiv.org/content/10.110…

We wrote a blog post in 2018 about the latest glutamate sensor - but times have progressed and so must we. @abhi_aggarwal1 updated our post to feature the new newest sensor: iGluSnF from @PodgorskiLab. hubs.la/Q017BC5b0