Category Archives: Microscopy

Heating up the objective for two-photon imaging

To image neurons in vivo with a large field of view, a large objective is necessary. This big piece of metal and glass is in indirect contact with the brain surface, with only water and maybe a cover slip in … Continue reading

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Temporal dispersion of spike rates from deconvolved calcium imaging data

On Twitter, Richie Hakim asked whether the toolbox Cascade for spike inference (preprint, Github) induces temporal dispersion of the predicted spiking activity compared to ground truth. This kind of temporal dispersion had been observed in a study from last year … Continue reading

Posted in Calcium Imaging, Data analysis, machine learning, Microscopy, Neuronal activity | Tagged , , | 1 Comment

Interview with Bruno Pichler

Bruno Pichler studied medicine, obtained a PhD in neuroscience, worked in the labs of Arthur Konnerth, Tom Mrsic-Flogel and Troy Margrie, and was R&D manager at Scientifica, before founding his own company, INSS, “to provide the international neuroscience community with … Continue reading

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Simultaneous calcium imaging and extracellular recording from the same neuron

Calcium imaging is a powerful method to record from many neurons simultaneously. But what do the recorded signals really mean? This question can only be properly addressed by experiments which record both calcium signals and action potentials from the same … Continue reading

Posted in Calcium Imaging, Data analysis, electrophysiology, machine learning, Microscopy, Neuronal activity, zebrafish | Tagged , , , , | Leave a comment

Alignment tools

This blog posts covers some tools and techniques that I’m typically using to align two-photon microscopes. If you’re an expert, you will probably find nothing new, but if you haven’t been doing this for years, this might offer you some … Continue reading

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A practical guide for adaptive optics

There is no standard curriculum to learn practical procedures about microscopy: how to align a setup, how to identify misalignments, how to identify broken parts, where to buy components, how to check their performance, and much more. How to learn … Continue reading

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Review: An artificial ground truth for calcium imaging

Selected paper: Charles, Song, Tank et al., Neural Anatomy and Optical Microscopy Simulation (NAOMi) for evaluating calcium imaging methods, bioRxiv (2019). What is the paper about? Calcium imaging is a central method to observe neuronal activity in the brain of … Continue reading

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Post-publication review: Somato-dendritic coupling of L5 neurons in V1

It requires more than a quick look at the abstract and the figures to fully understand a research paper and its limitations. One way to get there is to write a summary or critical review of a paper. In a contribution to … Continue reading

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Photon yield and pulse dispersion

This case report describes how a two-photon microscope was found to come with a fluorescence yield that was lower than expected; how the underlying cause was found out in a systematic manner; and how the problem was solved. All approaches and solutions are specific for the microscope under question. However, I hope that this report (1) will inspire other people who are troubleshooting or optimizing their microscopes, (2) will help other people better understand two-photon microscopes and the relevance of technical details. Continue reading

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Whole-cell patch clamp, part 4: look and feel

In previous blog posts, I have been discussing some aspects of whole-cell patch clamp recordings ([1], [2], [3], [4]). Today, I will show some instructive videos that I recorded during experiments. I’m hoping that they will convey the look and feel … Continue reading

Posted in Calcium Imaging, electrophysiology, Imaging, Microscopy, Neuronal activity, zebrafish | Tagged , , , | 3 Comments