Peter Rupprecht

Viewpoints: how the hippocampus contributes to memory, navigation and cognition - Nature Neuroscience The hippocampus serves a critical function in memory, navigation, and cognition. Nature Neuroscience asked John Lisman to lead a group of researchers in a dialog on shared and distinct viewpoints on t...

This "viewpoint" article on the function of hippocampus: www.nature.com/articles/nn....
Because it shows the disagreement within the field while highlighting the important questions.

Wow ...

Sounds interesting, and sorry that I cannot attend! Is this drift (both image responses and gaze) on a timescale of minutes? I find it difficult to imagine how such slow gaze drift would look like.

First whole-brain recording of social sound processing in a vertebrate. Surprises start in the hindbrain; thalamus gates conspecific calls; male and female brains diverge downstream. Work by @joerghenninger.bsky.social, @mh123.bsky.social sky.social and team. www.biorxiv.org/content/10.6...

Two-photon calcium imaging at 24,000 lines/s, with the resonant axis spanning 4x what other systems can do. Inertia-free. Diffraction-limited. No tradeoffs. Che-Hang Yu developed a 4x angle multiplier for laser scanning. His paper is out today: opg.optica.org/optica/fullt... 1/n #fluorescenceFriday

A man standing in front of scientific equipment, with a dubious and pained look on his face. Aluminium foil is prominently visible.

First time patching in months, y'all know what that means: I am about to spend the next few hours discovering fun and novel ways in which an ephys setup can break!

A database and deep learning toolbox for noise-optimized, generalized spike inference from calcium imaging - Nature Neuroscience Rupprecht et al. compiled a large database of simultaneous electrophysiological and calcium recordings from the same neurons. An algorithm (termed CASCADE) trained with this ground truth enables relia...

For more context, here's our original paper describing Cascade: www.nature.com/articles/s41...
And here's our preprint describing the models trained for use with GCaMP8 indicators: www.biorxiv.org/content/10.1...

CascadeTorch: a PyTorch version of Cascade for spike inference I’m glad to share a PyTorch-based implementation of spike inference from calcium imaging data: CascadeTorch, now available on GitHub. The original Cascade repository remains fully supported. …

Interested in deep learning-based spike inference with Cascade? We re-implemented the code in Torch -previously in Tensorflow - for better compatibility.

Blog: gcamp6f.com/2026/02/17/c...

GitHub: github.com/PTRRupprecht...

A new preprint introduces aDISCO, a DISCO-based clearing approach that makes whole archival FFPE human tissues transparent and antibody-compatible, enabling true 3D light-sheet histology across brain & multiple organs at cellular resolution. Aguzzi & Helmchen teams.
www.biorxiv.org/content/10.1...

subthreshold depolarization before a complex spike correlates with local calcium during the complex spike.

But then where do the branch-specific variations in voltage come from? We found that in apical dendrites, small subthreshold depolarizations *preceding* a complex spike partially predict voltage (and Ca2+) amplitude *during* the event. This suggests conjunctive amplification of inputs and spikes.

What's the relation between voltage and calcium in dendrites? Xiang Wu studied this in CA2 hippocampal pyramidal cells in behaving mice. www.biorxiv.org/content/10.6...

Many more details and analyses, on cell-type effects in astrocytes, pyramidal cells and interneurons during arousal versus optogenetic LC stimulation: www.biorxiv.org/content/10.6...
Huge congrats to Sian on her beautiful PhD work! 5/5

Example of activity traces obtained from calcium imaging for interneurons during natural arousal and artificial arousal (LC stimulation) across days.

A subpopulation of interneurons is directly activated by LC activation. Those interneurons are preferentially located in specific CA1 laminae. 4/5

Example of activity traces for astrocytes during natural arousal and artificial arousal (LC stimulation) across days.

Several interesting observations along the way. For example, astrocytes show diverse sensitivities to LC stimulation, variable across cells but consistently for each cell. 3/5

Scheme illustrating the central finding: LC stimulation vs. natural arousal elicit distinct cellular responses across cell types.

Our main finding is that natural arousal and optogenetic LC stimulation elicit strikingly distinct responses at the single-cell level. 2/5

Excited to share our new preprint! We explore the link between the locus coeruleus (LC) and arousal for astrocytes, pyramidal cells, interneurons in the hippocampus. A fantastic collaboration with @sianduss.bsky.social @bohaceklab.bsky.social, and many others: www.biorxiv.org/content/10.6... 1/5

What I meant is that a smart PDF reader could generate/guess the abbreviations, without any need to hard-code them for each instance of an abbreviation.

Google Scholar PDF Reader - Chrome Web Store Supercharge your paper reading: follow references, skim outline, jump to figures, cite and save.

Great idea, but works only with LaTeX. Maybe best to implement it via the *PDF reader*, not the PDF. Some browser addons for reading PDFs do this already by linking figure refs and citations (chromewebstore.google.com/detail/googl...)
Adding the same feature for abbreviations should be feasible.

That's a very interesting approach! What happens if you select the 10-20 best quadruplet rules and select neurons/synapses randomly from these rules? Wouldn't this diversity make the network/neuron more stable and capable? Curious about your take.

But from a scientific perspective, your approach (modeling first, then data analysis) seems absolutely valid to me!

In a paper, mixing modeling, data analysis and experiments may be more difficult to browse and follow for the average reader. In systems neuroscience, we are used to seeing first the data analysis and then - in the final figure - a model (which can be ignored by those who don't understand it).

Still have to read it carefully with all methods and details, but it's a candidate for my favorite paper of 2026! Very cool, and important work to understand how neurons and dendrites work!

Annual report of my intuition about the brain (2025, part III) How does the brain work, and how can we understand it? To approach this big question from a broad perspective, I want to report on some ideas about the brain that marked me most over the …

What would it really mean to achieve experimental goals that currently seem out of reach: a new blog post.

Part III - Simultaneously recording from all neurons of the human brain
gcamp6f.com/2026/01/03/a...

Annual report of my intuition about the brain (2025, part III) How does the brain work, and how can we understand it? To approach this big question from a broad perspective, I want to report on some ideas about the brain that marked me most over the …

What would it really mean to achieve experimental goals that currently seem out of reach: a new blog post.

Part II - Recording the inputs and the output of a single neuron in real time in vivo
gcamp6f.com/2025/12/30/a...

Annual report of my intuition about the brain (2025, part I) How does the brain work, and how can we understand it? To approach this big question from a broad perspective, I want to report on some ideas about the brain that marked me most over the …

What would it really mean to achieve experimental goals that currently seem out of reach: a new blog post.

Part I - connectomics
gcamp6f.com/2025/12/27/a...

New preprint from the lab! 🚀
We find that hippocampal OLM interneurons provide a circuit-level inhibitory feedback signal that dynamically controls when and where behavioral timescale synaptic plasticity can occur.
Feedback welcome!

What is the computational role of dendritic excitations? Byung Hun Lee and team mapped voltage dynamics throughout the dendritic trees of CA1 pyramidal neurons in mice navigating in virtual reality. www.biorxiv.org/content/10.6...

All the work by @colah.bsky.social (blog posts, distill etc.) is amazing - clear and transparent, with little or no jargon, trying to address the hard problems head-on.

Dirigo: a future Python alternative to Scanimage? Over the last 20 years, many microscopes that are capable of resonant scanning two-photon microscopy have converged on using ScanImage, a powerful software package with many strengths but also two …

Thankful for this blog piece by @ptrrupprecht.bsky.social on the Dirigo project. Glad you liked the posts!
gcamp6f.com/2025/11/14/d...

But I believe that post-publication reviews, or the suggestions that you've made, or simply transparent open reviews, which is used by many journals already, are a good way to read papers better and more efficiently. And this is a culture change that has already taken place during the last decade...