News

Accepted Symposium: Cell Diversity and Plasticity in the Mouse Olfactory System

Mai 16, 2025

We’re excited to share that the symposium on mouse olfactory research – organized by four of our graduate and undergraduate students (Hannah Tröger, Lena Terlau, Johanna Flesch, and Moritz Nesseler) – has been accepted for the program of the 2025 ECRO (European Chemoreception Research Organisation) Meeting this September.
The symposium will feature talks on cellular diversity, single-cell physiology, and circuit dynamics within the olfactory pathway, presented by early-career researchers from Europe and the US. Furhtermore, our own postdoctoral researcher, Andrés Hernandez-Clavijo, will be among the speakers!
If you’re planning to attend ECRO 2025, make sure to catch the symposium on Tuesday, September 16th at 11:15.

DFG Research Grants Programme – Individual Proposal

Mai 9, 2025

Dr. Andres Hernandez-Clavijo received an Individual Research Grant from the German Research Foundation (DFG) for the project „Unravelling the cell diversity in the accessory olfactory bulb (AOB) combining single cell transcriptomic analysis and electrophysiological approaches“. The main goal of the project is to use a multifaceted approach to investigate the cellular diversity in the mouse accessory olfactory bulb (AOB) mediating pheromone information processing and behavioral regulation. The funded period starts this year and will reach 2029.

Congratulations to Andres on acquiring this major grant! We are excited to see how this project developes.

New Publication: Ca2+-Activated Ion Channels Exert Opposite Effects in Different Signaling Compartments of Vomeronasal Sensory Neurons

April 17, 2025

Rudolf Degen, Victoria K Switacz, Jennifer Spehr, Marc Spehr (2025) Ca2+-Activated Ion Channels Exert Opposite Effects in Different Signaling Compartments of Vomeronasal Sensory Neurons. Journal of Neuroscience 16 April 2025, 45 (16) e2134242025; https://doi.org/10.1523/JNEUROSCI.2134-24.2025

Show abstract
In most mammals, conspecific chemical cues that drive innate social and sexual behavior are detected by the vomeronasal organ (VNO) and processed in the accessory olfactory bulb (AOB). Chemosensory stimulation of vomeronasal sensory neurons (VSNs) at their microvillous dendritic knobs triggers, first, a local signal transduction and amplification cascade and, second, transformation of that signal into action potential (AP) discharge at the soma. Both processes-signal transduction and AP generation-involve local Ca2+ elevations in the knob and soma, respectively. Here, we revisit the somewhat still controversial functions of Ca2+-activated ion channels in both VSN compartments. In acute mouse VNO slices (of either sex), focal photorelease of Ca2+ reveals that VSN knob and soma both act as independent Ca2+ signaling compartments, in which Ca2+ elevations exert opposite effects. While Ca2+ signals in the knob drive an excitatory inward current, Ca2+ elevations in the soma primarily activate hyperpolarizing outward currents that silence VSNs. A substantial fraction of the latter current is mediated by SK and/or BK channels. Notably, SK channel activity strongly affects VSN firing. Together, our study reveals a diverse composition of Ca2+-activated currents in VSN somata and uncovers an unexpected role of SK channels in dampening excitability and, thus, in controlling VSN-to-AOB information transfer.

New Publication: Kir7.1 is the physiological target for hormones and steroids that regulate uteroplacental function

März 11, 2025

Haoui M, Vergara C, Kenzler L, Schröer J, Zimmer-Bensch G, Fleck D, Wiesbrock C, Spehr M, Lishko PV (2025) Kir7.1 is the physiological target for hormones and steroids that regulate uteroplacental function. Science Advances DOI: https://doi.org/10.1126/sciadv.adr5086

ERS Grants for Two Projects in the Chemosensation Group

Februar 6, 2025

We are excited to announce that two new research projects in our group got funded by RWTH Aachen’s Exploratory Research Space (25th call „Bioinspired Sensory Systems“).

Dr. Christopher Wiesbrock, Prof. Dr. Simon Musall (Institute for Biology II, RWTH Aachen), and Dr. Viviana Rincón Montes (Research Center Jülich, Institute of Bioelectronics, IBI-3), lead a project that aims to record neural activity from the accessory olfactory bulb (AOB) in freely-moving mice. This interdisciplinary approach combines advanced microelectrode technology, neural data analysis, and behavioral studies to gain unprecedented insights into pheromone processing.

Dr. Andres Hernandez-Clavijo and Dr. Natja Haag (Institute for Human Genetics and Genomic Medicine, Medical Faculty, RWTH Aachen University) lead the project „Deciphering the neuronal diversity linking pheromone signaling and behavior regulation in the mammalian brain“. With this seed funds, Dr. Andres Hernandez-Clavijo and Dr. Haag would like to investigate the transcriptomic profiling of the neuronal heterogeneity in the mouse accessory olfactory bulb at single cell resolution.

Congratulations to everyone involved for bringing these exciting projects to life!

Teaching Award 2024 for Prof. Marc Spehr

Januar 24, 2025

We are pleased to announce that Prof. Marc Spehr was awarded the Teaching Award of €5,000 on November 22, 2024, by the Student Council of Biological Sciences at RWTH Aachen University.

From left to right: Jule Stark (Biology Student Council), Prof. Dr. Marc Spehr (Head of the Institute of Biology 2 Chemosensory Research), Prof. Marco Oldiges (IBG-1), Lea Steffens (Biology Student Council).
From left to right: Jule Stark (Biology Student Council), Prof. Dr. Marc Spehr (Head of the Institute of Biology 2 Chemosensory Research), Prof. Marco Oldiges (Head of Bioprocesses and Bioanalytics), Lea Steffens (Biology Student Council).

This award recognizes the exceptional commitment of lecturers to university teaching and reflects the appreciation of students for outstanding teaching performance.

Congratulations to Prof. Marc Spehr and Prof. Marco Oldiges on their well-deserved recognition!

New Publication: Single-neuron representations of odours in the human brain

Oktober 23, 2024

Marcel S. Kehl, Sina Mackay, Kathrin Ohla, Matthias Schneider, Valeri Borger, Rainer Surges, Marc Spehr & Florian Mormann (2024) Single-neuron representations of odours in the human brain. Nature 634, 626–634 . https://doi.org/10.1038/s41586-024-08016-5

Show abstract
Olfaction is a fundamental sensory modality that guides animal and human behaviour1,2. However, the underlying neural processes of human olfaction are still poorly understood at the fundamental—that is, the single-neuron—level. Here we report recordings of single-neuron activity in the piriform cortex and medial temporal lobe in awake humans performing an odour rating and identification task. We identified odour-modulated neurons within the piriform cortex, amygdala, entorhinal cortex and hippocampus. In each of these regions, neuronal firing accurately encodes odour identity. Notably, repeated odour presentations reduce response firing rates, demonstrating central repetition suppression and habituation. Different medial temporal lobe regions have distinct roles in odour processing, with amygdala neurons encoding subjective odour valence, and hippocampal neurons predicting behavioural odour identification performance. Whereas piriform neurons preferably encode chemical odour identity, hippocampal activity reflects subjective odour perception. Critically, we identify that piriform cortex neurons reliably encode odour-related images, supporting a multimodal role of the human piriform cortex. We also observe marked cross-modal coding of both odours and images, especially in the amygdala and piriform cortex. Moreover, we identify neurons that respond to semantically coherent odour and image information, demonstrating conceptual coding schemes in olfaction. Our results bridge the long-standing gap between animal models and non-invasive human studies and advance our understanding of odour processing in the human brain by identifying neuronal odour-coding principles, regional functional differences and cross-modal integration.

Progress Report Retreat: A Successful Three-Day Event

September 12, 2024

From September 4th to 6th, 2024, our team gathered for a productive and enjoyable three-day retreat at Gut Alte Heide to present and discuss our progress report.
Each team member had the opportunity to present their data, which led to engaging discussions and valuable feedback. These presentations not only showcased our progress but also allowed us to learn from each other and improve our scientific presentation techniques.
After the talks, we had a lot of fun together. Being in nature and away from everyday distractions helped us bond as a team and recharge our creative energies.
Overall, the event was a great success. We left with new insights, stronger connections, and renewed enthusiasm for the next phase of our project.

Veränderungen im Sekretariat

August 5, 2024

Unsere Sekretärin Marijke Steitz hat das Institut verlassen, um eine längere Reise anzutreten. Ihre Aufgaben übernimmt ab sofort Theresa Schürz. Wir danken Marijke herzlich für ihre tolle Arbeit und wünschen ihr alles Gute auf ihren Wegen und eine tolle Erfahrung!

News from ISOT 2024 Reykjavik, Iceland

Juli 1, 2024

The chemosensation laboratory was represented by 8 members (Victoria Switacz, Hannah-Lena Tröger, Melissa Franke, Andres Hernandez-Clavijo, Lena Terlau, Fabian Quicken, Friederike Seifert, Christoph Hamacher) at the international symposium for smell and taste (ISOT) in Reykjavik, Iceland. In total, they presented 7 posters. Andres received a travel grant. Congrats, Andres!

News from FENS and ENCODS 2024

Our doctoral student, Moritz Nesseler, recently attended two neuroscience conferences in Vienna.
At ENCODS2024, a conference organized by and for neuroscience PhD students, he had the opportunity to connect with fellow PhD students and discuss shared research interests. Here, Moritz was awarded the Best Poster Award for his presentation on “Potential integration of main and accessory olfactory bulb axonal projections in the mouse amygdala”.
Following ENCODS2024, Moritz participated in FENS2024, the largest European neuroscience conference. Here, he engaged with leading experts and attended various sessions, exchanging ideas and gaining insights.

New Publication: A revised conceptual framework for mouse vomeronasal pumping and stimulus sampling

Februar 19, 2024

Christoph Hamacher, Rudolf Degen, Melissa Franke, Victoria K. Switacz, David Fleck, Raghu Ram Katreddi, Andres Hernandez-Clavijo, Martin Strauch, Nao Horio, Enno Hachgenei, Jennifer Spehr, Stephen D. Liberles, Dorit Merhof, Paolo E. Forni, Geraldine Zimmer-Bensch, Yoram Ben-Shaul, and Marc Spehr (2024) A revised conceptual framework for mouse vomeronasal pumping and stimulus sampling, Current Biology 34, https://doi.org/10.1016/j.cub.2024.01.036

Show abstract
The physiological performance of any sensory organ is determined by its anatomy and physical properties. Consequently, complex sensory structures with elaborate features have evolved to optimize stimulus detection. Understanding these structures and their physical nature forms the basis for mechanistic insights into sensory function. Despite its crucial role as a sensor for pheromones and other behaviorally instructive chemical cues, the vomeronasal organ (VNO) remains a poorly characterized mammalian sensory structure. Fundamental principles of its physico-mechanical function, including basic aspects of stimulus sampling, remain poorly explored. Here, we revisit the classical vasomotor pump hypothesis of vomeronasal stimulus uptake. Using advanced anatomical, histological, and physiological methods, we demonstrate that large parts of the lateral mouse VNO are composed of smooth muscle. Vomeronasal smooth muscle tissue comprises two subsets of fibers with distinct topography, structure, excitation-contraction coupling, and, ultimately, contractile properties. Specifically, contractions of a large population of noradrenaline-sensitive cells mediate both transverse and longitudinal lumen expansion, whereas cholinergic stimulation targets an adluminal group of smooth muscle fibers. The latter run parallel to the VNO’s rostro-caudal axis and are ideally situated to mediate antagonistic longitudinal constriction of the lumen. This newly discovered arrangement implies a novel mode of function. Single-cell transcriptomics and pharmacological profiling reveal the receptor subtypes involved. Finally, 2D/3D tomography provides non-invasive insight into the intact VNO’s anatomy and mechanics, enables measurement of luminal fluid volume, and allows an assessment of relative volume change upon noradrenergic stimulation. Together, we propose a revised conceptual framework for mouse vomeronasal pumping and, thus, stimulus sampling.

News from ECRO 2023 in Nijmegen

Oktober 6, 2023

7 members of the Chemosensation laboratory attended the annual meeting of the European Chemoreception Research Organization (ECRO). They represented the lab in full forces: Victoria, Christoph, Johanna and Moritz successfully presented their projects on posters. Additionally, Victoria, Andres and Moritz organized a symposium called ‚Novel perspectives in mouse olfaction‘, inviting junior group leaders to present their current work. The Spehr lab was represented with a talk in this symposium held by Friederike.
Johanna received a ECRO travel grant to cover for her expenses. Congrats Johanna!

News from the ETW2023

Juni 18, 2023

Five members of our group, Jerome Schröer, Lina Kenzler, David Fleck, Michelle Nowara, and Ilian Schröder (from left to right in the photo), attended the European Testis Workshop 2023 (ETW2023). This workshop brought together experts from the fields of reproductive biology and medicine to share their insights.

Four of our participants received funding from the Male Contraceptive Initiative (MCI) to cover their travel expenses. Lina Kenzler, Michelle Nowara, Jerome Schröer, and Ilian Schröder were the recipients of this grant, enabling their valuable contributions to the conference.

News from AChemS 2023

April 24, 2023

Lena Terlau, Friederike Seifert, Stefanie Kurth, Melissa Franke, and Marc Spehr attended the annual meeting of the Association for Chemoreception Sciences (AChemS) 2023, which took place in Bonita Springs, Florida. 

Lena received a travel grant from the European Chemoreception Research Organization (ECRO) that funded her participation. Moreover, at the meeting, Lena won the prestigious AChemS Award for Undergraduate Research for her poster presentation entitled “Insights into Adult Neurogenesis of Vomeronasal Sensory Neurons” Congratulations, Lena!!!