Tag Archives: photons

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 , , , | 1 Comment

Alvarez lenses and other strangely shaped optical elements

In typical microscopes, lenses or mirrors are moved forth and back to change the position of their focus. Tunable lenses like the electro-tunable lens or the TAG lens, on the other hand, are deformed by an external force and thereby … Continue reading

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Springtime for two-photon microscopy

Today, the fields and forests around Basel are full of flowers that try to disseminate their pollen. Fixed pollen are, apart from sub-diffraction beads and the convallaria rhizome, one of the most commonly used test/reference samples for fluorescence microscopy. This … Continue reading

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Can two-photon scanning be too fast?

The following back-of-the-envelope calculations do not lead to any useful result, but you might be interesting in reading through them if you want to get a better understanding of what happens during two-photon excitation microscopy. The basic idea of two-photon microscopy … Continue reading

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All-optical entirely passive laser scanning with MHz rates

Is it possible to let a laser beam scan over an angle without moving any mechanical parts to deflect the beam? It is. One strategy is to use a very short-pulsed laser beam: A short pulse width means a finite … Continue reading

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