“I’m delighted that my work is being acknowledged in this way,” says Professor Tobias Ackels. “As well as bringing important recognition for me personally, winning the prize is also a major vote of confidence that will give me momentum for my future career. This award will motivate me to stick rigorously to the course I’ve set myself and push ahead with my research in order to gain a better understanding of how we perceive our environment.”
“Through his research, Tobias Ackels is unlocking some completely new insights into how our sense of smell works,” reveals Professor Bernd Weber, Dean of the Faculty of Medicine at the University of Bonn and acting Executive Committee Chair of the University Hospital Bonn. “We’re very happy to have been able to secure his services for the University of Bonn.” Tobias Ackels came to Bonn from the London-based Francis Crick Institute in time for the start of the 2023/24 winter semester.
Differentiating between smells in an instant
As far as nocturnal animals are concerned, their sense of smell is their most important tool for sniffing their way around in the dark. This is not easy, because every smell is composed of many different molecules and every natural scent is made up of a large number of smells that change all the time. In the past, the “sniff” was regarded as the smallest unit of information in odor processing. But Tobias Ackels, who is a member of the Life and Health Transdisciplinary Research Area (TRA) at the University of Bonn, has proven this not to be the case: even between sniffs, mammals are absorbing information that can influence their behavior.
In mice, just as in humans, smells are registered by olfactory cells in the nasal mucosa. Each of these nerve cells carries only one type of olfactory receptor. Mice have over 1,000 of these types and humans around 350. Several thousand olfactory cells carry the same receptor in each case. If an odorant molecule binds to it, it triggers a—relatively slow—signaling cascade inside the cell, whereupon the various pieces of information come together in the brain’s olfactory bulb with a slight time lag. This delayed convergence increases the amount of information contained in the signals from the olfactory cells, thus making the olfactory bulb receptive to rapidly changing stimuli that would otherwise be lost. Tobias Ackels confirmed this hypothesis first in a computer model and then using a fluorescence microscope to get measurements of nerve cell activity in mice that had been exposed to stimuli of this kind.
Ackels then took a group of thirsty mice and presented them with mixtures of two odors, correlated either synchronously or asynchronously, that fluctuated within a high frequency range. In so doing, he simulated the situation that they would encounter in their natural environment. Synchronous odors are those that all originate in the same place, while asynchronous ones come from different locations. Half of the mice were rewarded with water when they recognized a synchronous stimulus, the other half when they recognized an asynchronous one. Both groups learned to tell the difference and became able to do so up to a fluctuation frequency of 40 hertz, thus demonstrating that they smell faster than they breathe: with fluctuations of up to 40 times per second, they can glean spatial information from scents. “These observations indicate that mammals can use this ability to distinguish at lightning speed between sources of different olfactory signals in order to find their way around,” explains Ackels, who does his research at the University Hospital Bonn’s Institute of Experimental Epileptology and Cognition Research. This is also important for us humans, as we will smell a forest fire before we spot it, for example.
An early-warning system for dementia?
Tobias Ackels is currently using his Starting Grant from the European Research Council (ERC) to study how information is extracted from the olfactory bulb and passed on to higher regions of the rhinencephalon, or “olfactory brain,” and what role so-called interneurons play in this process. “There are suggestions that a failing sense of smell might be an early sign of dementia, because a deterioration in our ability to smell often precedes the structural changes, poor memory and clinical symptoms associated with the disease,” says Ackels. This hypothesis is one area in which his basic research could be applied in practice, about which he is engaging in close dialogue with clinicians at the German Center for Neurodegenerative Diseases (DZNE) in Bonn.
About Tobias Ackels
Professor Tobias Ackels studied biology at RWTH Aachen University from 2005 to 2011, obtaining his doctorate there in 2015 with a thesis on signal processing in the olfactory system in mammals. Between 2015 and 2023, he worked as a postdoc in the group led by Professor Andreas Schäfer at the Francis Crick Institute in London. He returned to Germany in August 2023, accepting a W2 professorship at the University of Bonn, and currently heads up the “Sensory Dynamics and Behaviour” group in the Institute of Experimental Epileptology and Cognition Research at the University Hospital Bonn. 2023 also saw him awarded an ERC Starting Grant.
About the Paul Ehrlich and Ludwig Darmstaedter Early Career Award
The Paul Ehrlich Foundation presents the award once a year to an early-career researcher working in Germany in recognition of their outstanding research in the field of biomedicine. The €60,000 prize money has to be put toward research. The award, together with the Main Prize for 2025, will be presented by the Chairman of the Scientific Council of the Paul Ehrlich Foundation at a ceremony held in Frankfurt’s Paulskirche church at 5 pm on March 14, 2025.