News

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

October 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

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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.

Changes in the Secretariat

August 5, 2024

Our secretary, Marijke Steitz, has left the institute to embark on a long journey. Her duties will now be taken over by Theresa Schürz. We sincerely thank Marijke for her great work and wish her all the best on her travels and a wonderful experience!

News from ISOT 2024 Reykjavik, Iceland

July 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!

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

February 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

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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

October 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

June 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

June 16, 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!!!

News from NWG Göttingen

March 25, 2023

Victoria Switacz, Hannah Tröger, Moritz Nesseler and Friederike Seifert travelled to Göttingen and participated at the 15th Göttingen meeting of the German Neuroscience Society. They all successfully presented great posters.
See you again in 2025, Göttingen!

Friederike returns from Pennsylvania

October 17, 2022

Friederike came back from a 6-month research stay at Ma lab, University of Pennsylvania, Philadelphia. She learned to do in vivo virus-injections into the accessory olfactory bulb. These injections were used to chemogenetically inhibit Mitral cells during behavioural experiments.