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Jan Siemens

@jansiemens.bsky.social

130 followers 82 following 35 posts

Heat, cold, brain - viva sensory science and the hypothalamus https://siemenslab.de/

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Jan Siemens @jansiemens.bsky.social · May 11

How does temperature interact with the brain? This coming Wednesday Eve Marder, Laura Duvall and I will talk about thermally-induced neural activity, plasticity and the like.

Society for Neuroscience @sfn.org · May 8

Claim your spot now for the next webinar in partnership with @kavlifoundation.bsky.social!

Join the conversation as experts discuss mechanisms of neural adaptation in changing environments and recent advances in the field.

Register now: bit.ly/4k7h3MX

#NeuroSky

Promotional graphic for a Society for Neuroscience and The Kavli Foundation event titled 'Neuromodulatory Adaptation and Plasticity in Changing Environments’ on Wednesday, May 14, 11:30 a.m.–12:30 p.m. EDT. Features images of speakers Laura Duvall, PhD from Columbia University, Eve Marder, PhD from Brandeis University, and Jan-Erik Siemens, PhD from Heidelberg University.

Jan Siemens @jansiemens.bsky.social · Apr 20

Thank you Alexander -- yes, temperature science allows for easy wordplays

Jan Siemens @jansiemens.bsky.social · Apr 20

Summary: Different TRP channels shape how warmth is sensed: Trpv1 helps detect fast changes, Trpm2 supports stable warm preference. Curious to hear your thoughts.

Jan Siemens @jansiemens.bsky.social · Apr 20

We modeled mouse behavior with a drift-diffusion model: Trpv1-KO mice have less fidelity in detecting warm temp differences but compensate with higher sampling rate leading to an overall preference similar to wildtype mice. Trpm2-KOs fail to accumulate temp evidence, losing 31°C preference.

Jan Siemens @jansiemens.bsky.social · Apr 20

In agreement with this idea: in mice overexpressing Trpv1, neurons respond to warmth faster—and in the behavior assay the mice quickly lock onto 31°C, switching rooms less than wildtypes (purple: Trpv1 overexpressor mice; grey wildtypes).

Jan Siemens @jansiemens.bsky.social · Apr 20

Calcium imaging of cultured neurons reveals Trpv1 mediates the rapid neuronal response to warming, and less the steady-state signal. This suggests that the rate of temperature increase might be encoded by Trpv1 (each triangle is the responds onset to the warmth stimulus; x-axis: time in seconds)

Jan Siemens @jansiemens.bsky.social · Apr 20

Tracking data shows Trpv1-KOs switch rooms more often—possibly compensating for difficulty sensing warmth.. (Yellow = TRPV1 KO mice)

Jan Siemens @jansiemens.bsky.social · Apr 20

Trpv1-KO mice behave similar to wildtypes overall, but show trouble deciding early on (see above) —suggesting a delay in detecting the warmth difference.

Jan Siemens @jansiemens.bsky.social · Apr 20

Trpm2-KO mice no longer prefer 31°C and spend equal time at 34–38°C, suggesting Trpm2 is key for selecting innocuous warm temps.

Jan Siemens @jansiemens.bsky.social · Apr 20

Compared to floor-only tests, the chamber assay better detects subtle warm temp differences. Mice prefer temps nearer their thermoneutral zone (~31°C). Pink = chamber; black = classic plate assay.

Jan Siemens @jansiemens.bsky.social · Apr 20

So we built a chamber-based assay where we can precisely control full-room temps (including floor) via Peltier elements. Mice choose between two rooms via a tunnel (but don’t linger there!).

Jan Siemens @jansiemens.bsky.social · Apr 20

Ambient temperature is a whole-body experience —but most tests only use heated floors, mainly probing paw/snout sensitivity. These setups might also alter room temp unpredictably, which is rarely measured/reported.

Jan Siemens @jansiemens.bsky.social · Apr 20

How do mice decide which ambient temperature they prefer? Our new eLife paper by Muad (@hummuscience.bsky.social) explores how TRPV1 and TRPM2 channels shape temperature preference. A quick breakdown 👇
🔗 pubmed.ncbi.nlm.nih.gov/40215103/

Diverging roles of TRPV1 and TRPM2 in warm-temperature detection - PubMed

The perception of innocuous temperatures is crucial for thermoregulation. The TRP ion channels TRPV1 and TRPM2 have been implicated in warmth detection, yet their precise roles remain unclear. A key c...

pubmed.ncbi.nlm.nih.gov

Reposted by Jan Siemens

Meg Tirrell @megtirrell.bsky.social · Apr 9

Amid the Trump admin's dismantling of the US scientific ecosystem, Nobel Prize-winner @ardemp.bskyverified.social writes on @cnn.com: "I’ve already been approached with an offer to relocate my lab to China, complete with a promise of 20 years of stable research funding." www.cnn.com/2025/04/09/h...

Nobel laureate: I owe America my success. Today, its scientific future is in danger | CNN

Dr. Ardem Patapoutian says he watches “with deep sadness as the United States’ remarkable scientific enterprise, which took generations of hard work and national investment to build, faces a concerted...

Jan Siemens @jansiemens.bsky.social · Apr 19

This was a great meeting to mix and mingle with scientists of diverse fields broadly interested in how long-term environmental changes modulate neurobiology - thank you @kavlifoundation.bsky.social‬ and @alleninstitute.bsky.social !

The Kavli Foundation @kavlifoundation.org · Apr 15

Welcome to the Neurobiology in Changing Environments symposium! We’re thrilled to begin this important gathering exploring how nervous systems respond to our rapidly shifting world. #KavliNeuro #FrontierScience #NiCE

Jan Siemens @jansiemens.bsky.social · Mar 12

Very interesting study by Lin Yuan & Co in the Julius lab, explaining how sensory neurons can adapt to exitotoxicity and calcium challenges e.g. by Trpv1 activation. Spoiler alert: the electron transport chain is involved - we enjoyed discussing it in Journal club.

www.biorxiv.org/content/10.1...

Metabolic tuning facilitates nociceptor resilience to excitotoxicity

The capsaicin receptor, TRPV1, mediates the detection of harmful chemical and thermal stimuli. Overactivation of TRPV1 can lead to cellular damage or death through excitotoxicity, a phenomenon associa...

www.biorxiv.org

Reposted by Jan Siemens

Stefan Niggemeier @niggi.bsky.social · Feb 24

Bodo Ramelow übt sehr nachvollziehbare Kritik auch an der Rolle der Medien beim Wahlerfolg der AfD, weil alle über kein anderes Thema als „kriminelle Ausländer“ mehr gesprochen haben. www.deutschlandfunk.de/interview-mi...

Interview mit Bodo Ramelow, Linke, Ex-Ministerpräsident Thüringen, zur Wahl

www.deutschlandfunk.de

Reposted by Jan Siemens

Kristin Knouse @kristinknouse.bsky.social · Feb 24

Can we perform genome-wide screens in any cell type in the body?! Excited to share our roadmap for leveraging advances in sgRNA delivery, library design, and phenotypic selection to enable unprecedented genetic dissection of organismal physiology and disease.

www.cell.com/cell-genomic...

A roadmap toward genome-wide CRISPR screening throughout the organism

Genome-wide CRISPR screening in the organism has tremendous potential to answer long-standing questions of physiology and disease; however, technical limitations have prevented its broad application. ...

Jan Siemens @jansiemens.bsky.social · Feb 8

On February 12, shortly before “High noon”, scientists at German research campuses, including here in Heidelberg, will stand up for Democracy: “facts, not fake news are needed for democracy”. See aufstehenfuerdemokratie.de/englisch/ – there is also find a Petition related to the cause. Get involved.

Reposted by Jan Siemens

Katharine Gammon @kategammon.bsky.social · Jan 9

This is true. LA County has a population greater than that of 40 individual U.S. states.

Matt Shipman (he/him) @shiplives.bsky.social · Jan 9

Los Angeles County is 4,751 square miles -- almost twice as large as Delaware.

It is home to more than 9.5M people. Larger than Virginia or Arizona; more than twice the population of Louisiana or Kentucky.

It has a larger GDP than Ohio or Georgia.

These fires are a truly national crisis.

Jan Siemens @jansiemens.bsky.social · Dec 27

Just finished the book "Transformer" by Nick Lane, great inspiration to evolutionary biologists, bochemists and, yes, also neuroscientists - its all about transformation of organic molecules and energy flow and not (only) about genes. Highly recommended nick-lane.net/books/transf...

Transformer: The Deep Chemistry of Life and Death — Nick Lane

What brings the Earth to life, and our own lives to an end? Nick Lane turns the standard view upside down, focusing on Krebs cycle

Jan Siemens @jansiemens.bsky.social · Dec 23

A short, personal account how our recent heat acclimation study came to life -- paywall-free version can be found here rdcu.be/d38Xr

Heat acclimation induces hypothalamic temperature sensitivity that promotes heat tolerance

Nature Neuroscience - After long-term heat exposure, a discrete group of hypothalamic neurons in the anterior ventromedial preoptic area become hyperactive and acquire temperature sensitivity. This...

Jan Siemens @jansiemens.bsky.social · Dec 23

Interesting thoughts on the type of biological problems AI research can help with, the complexity of biology that requires human intellect (and cannot be replaced by AI -- at least not currently, but I think it never will...), and human language that connects it all.

Sam Rodriques @sgrodriques.bsky.social · Dec 21

The essential role of natural language in representing biology

--AI-Science community all-in on bio foundation models, will no-doubt be awesome
--However, the representation spaces in those models are too structured for most phenomena
--Language will be essential, currently largely underappreciated

The essential role of natural language in representing biology

At the time of writing, it is December 2024, and I am at NeurIPS. The word of the day, at least in the AI for Biology community, is foundation models. Everyone wants bigger data on more things to thro...

www.sam-rodriques.com

Reposted by Jan Siemens

Richard Sever @richardsever.bsky.social · Dec 21

Many academics point to bioRxiv as “the one thing improving science publishing”.

If so, the one thing you all can do is persuade colleagues to submit and make this a norm. 1/2

Jan Siemens @jansiemens.bsky.social · Dec 23

Pain research: Exciting insight into "silent" (or "sleeping") pain-sensing neurons from the Lampert Lab!

Angelika Lampert @lampertlab.bsky.social · Dec 22

Preprint alert: Using human microneurography protocols in PatchSeq experiments on pig DRGs we identify the molecular identity of human dermal CMi-fibers (sleeping nociceptors). We provide an integrated pig-human-more transcriptomic atlas and identify OSMR and SST as marker, backed by human expts.

bioRxiv Neuroscience @biorxiv-neursci.bsky.social · Dec 21

Molecular architecture of human dermal sleeping nociceptors https://www.biorxiv.org/content/10.1101/2024.12.20.629638v1