...to study the basic biophysical mechanisms enabling animals to sense the required cues in their environment. In this project we will use different ultra-fast electronic spectroscopy techniques to elucidate the fundamental charge and spin transfer processes underlying radical pair formation in cryptochromes. These experiments shall selectively probe the dynamics of radical pairs in their singlet and triplet states, provide evidence for coherent singlet-triplet interconversion and, thus, test a cornerstone of the currently proposed models for radical-pair based magnetoreception. 

Team: Christoph Lienau, Antonietta de Sio, Daniel Timmer

...to investigate the basic biophysical mechanisms enabling the animals to sense the required cues in their environment. The aim of this project is to identify a structural candidate for a putative magnetite-based magnetoreceptor in sensory nerve endings of the ophthalmic branch of the trigeminal nerve in fishes und birds. For this purpose, we will use light-microscopy combined with spatially resolved magnetometry to detect magnetic particles in neuronally labelled tissue slices and electron microscopy to reveal their ultrastructure.

Team: Michael Winklhofer, Laura Ziegenbalg, Franziska Curdt

...to identify the molecules that interact with the primary magnetic sensors and the molecules in a downstream signalling cascade that eventually trigger a change in the membrane potential of the primary signalling cascade. We identified six putative protein interaction partners of European robin cryptochrome 4a, which all code for retina specific proteins. We therefore focus on characterising cryptochrome mediated binding processes using biochemical and biophysical methods including protein-membrane interaction processes. Our studies also aim at characterising the trigger events that start initiate the downstream signalling cascade.

Team: Karl-Wilhelm Koch, Ümmügülsüm Güzelsoy, Srdan Vujinovic

...to reveal the fundamental processes that make magnetic sensing robust. We will use molecular dynamics and spin dynamics simulations to elucidate the fundamental physical and chemical requirements for cryptochrome-based magnetoreception and to make predictions for critical experimental tests of the hypothesis in migratory animals. Project 1 will study the molecular origins of the interactions of cryptochrome with its key interaction partners. Project 2 will use computer simulations to guide and interpret the results of experimental studies of the magnetic sensitivity of cryptochromes in vivo and ex vivo and to understand more completely the operation of a radical pair magnetoreceptor.

Team: Ilia Solov'yov, Peter J. Hore, Gesa Grüning, Anders Frederiksen, Jonathan Hungerland

...to understand the functional and evolutionary history of cryptochrome magnetic sensitivity. Using the protein production pipeline and mutational strategies set up during the first funding period, this project will produce a variety of cryptochrome mutants from several different bird species. The magnetic sensitivity of these mutated proteins will be measured spectroscopically by our Mercator Fellows and collaborators in Oxford. Based on the insight from new protein mutants, spectroscopic measurements, theoretical predictions, and phylogenetic analyses, we will investigate why some cryptochromes are more magnetically sensitive than others.

Team: Henrik Mouritsen, Christiane Timmel, Stuart Mackenzie, Rabea Bartölke, Bahareh Dabirmanesh

...to study which neuronal cell types and pathways in the retina are involved in the processing of magnetic signals. The processing of magnetic compass information in migratory birds is initiated in the retina, presumably in cryptochrome 4-expressing double cone photoreceptors. Magnetic information is likely sent from retinal ganglion to higher brain areas cells via the thalamofugal pathway. However, the retinal circuitry that processes magnetic information is not known so far. To investigate this, we will combine electrophysiological recordings with a detailed morphological analysis of the processing pathways in the bird retina.

Team: Karin Dedek, Vaishnavi Balaji, Julia Joanna Forst

...to study how light-dependent magnetic signals are represented at the level of retinal ganglion cells and how the retina separates magnetic field changes from changes in light-intensity, colour, and polarisation. According to the hypothesis of a light-dependent radical pair mechanism in the eye of migratory birds, magnetosensory information is embedded in the responses of retinal ganglion cells. We are using large-scale multi-electrode arrays to record the activity of large fractions of ganglion cells while exposing the retina to magnetic and visual stimulation. We found strong evidence of magnetosensitive ganglion cells and will build on these results to understand how magnetosensory information is encoded in ganglion cell responses.

Team: Martin Greschner, Max Manackin

...to identify where multisensory integration of navigation-relevant information from all senses used takes place in the brain. This project aims to reveal the anatomical foundations with which birds integrate sensory input, set navigational goals, use them to compute and control navigational directions, and finally activate the appropriate motor output. To this end, we will trace key sensory pathways from their first area of representation in the telencephalon, via a 'prefrontal' area and the hippocampus down to the motor output structures. By using both long-distance night-migratory songbirds and shorter-distance diurnally migrating pigeons, we will cover the variety of anatomical blueprints of navigating birds.

Team: Onur Güntürkün, Dominik Heyers, Dinora Abdulazhanova

...to study how the brain encodes places (map), directions (compass), and goals. Navigation is about getting from point ‘A’ to point ‘B’. We know a lot about encoding of point ‘A’ (the animal’s position) by place- and grid-cells, but much less is known about the neural representation of point ‘B’ (the animal’s goal). Likewise, little is known about the neural basis of navigation in complex environments. We will study these questions in Egyptian fruit bats navigating through a very large maze containing several goals; neural activity will be recorded by a world-unique wireless electrophysiology device (neural-logger), which we developed. These experiments will provide novel insights on the neural basis of natural navigation.

Team: Nachum Ulanowski, Shaked Palgi

...to know whether the spatial cell types encoding places (map), directions (compass), and goals discovered in mammals also exist in birds, the most studied long-distance navigators. This project represents the journey of a 12-year quest to find neurons in the avian brain that code for processes that enable a computation of map and compass. Such neurons are key to understanding how short and long-distance navigation is represented in the brain. By combining the joint expertise of three labs, we will search with single cell recordings in freely moving and/or flying birds for avian hippocampal neurons that code for relevant spatial properties that inform the animal about its present location, goal, and heading direction. 

Team: Onur Güntürkün, Henrik Mouritsen, Nachum Ulanovsky, Masahiro Inda

...that hypotheses generated from theory, biochemistry, molecular biology, neuroanatomy, and/or neurophysiology can be validated at the behavioural level. Therefore, this project will develop RNAi knockdown techniques and use behavioural tests in orientation cages under meticulously controlled static and time-dependent magnetic fields to test predictions made by the signal detection and neural processing sections. The obtained results will feed back lessons learned from behaviour to the sections the hypotheses originated from.

Team: Henrik Mouritsen, Constance Scharff, Ezequiel Mendoza, Baladev Satish

...that key behavioural results obtained in the laboratory be retested in the wild with freely-moving animals. During the first funding period, we obtained fundamental and unexpected results, namely no effects of electrosmog or a magnetic pulse on the departure direction of free-flying migratory birds. Logical follow-up questions are: Does electrosmog, which corrupts the birds’ magnetic compass in the laboratory, affect the departure decisions of migratory birds when a further compass system (e.g., star compass) is not available? Does a magnetic pulse affect the compensation ability of virtually translocated migratory birds?

Team: Heiko Schmaljohann, Annika Peter

...to consider the consequences of proposed navigational capacities and behaviour and related sensory mechanisms at spatial and temporal scales beyond those observable in the lab or in field experiments. To this end, we developed a modelling framework to assess orientation strategies based on geophysical compass cues, focusing on performance among compass courses on a global scale. The logical extension through enhanced SFB-collaborations is to model true navigation, collective migration of fish and bats versus solitary migratory birds and how migration routes evolve based on input from magnetic sensors.

Team: Bernd Blasius, Heiko Schmaljohann, James McLaren

...to gain a detailed understanding of the genomic background of the organisms that we investigate on various levels. Individual sequencing data not only provide access to the complete genomic inventory of our focal study species, but further facilitates the development of a strong molecular toolset. This enables us to identify regions in the genome that show variation with relevance for the behavioural phenotype, characterise variability and functional relevance of particular candidate loci along the genome, and beyond that open the opportunity to evaluate and interpret our findings in an evolutionary framework. This is particularly exciting in night-migratory songbirds where a strong genetic component of migratory behaviour has been demonstrated. 

Team: Miriam Liedvogel, Georg Manthey, Sonam Kulkarni

...to understand whether the mechanisms and principles of magnetoreception are similar across taxa. In this project, we will focus on migratory bats. By measuring orientation decisions following magnetic treatments in either a field laboratory or under free-flight conditions in radio-tagged bats by utilising a network of digital telemetry stations, we are now able to test the two prevailing hypotheses, the radical-pair-based and the magnetic-particle-based magnetoreception mechanism, in a mammalian model. 

Team: Oliver Lindecke, Fedor Tsellarius, Pegah Negahdar

...to understand the evolutionary potential and trajectories of migratory behaviour, which in turn requires detailed knowledge of the patterns, sources, and consequences of variance in the migratory phenotype, including variance in orientation and navigation. We collected 192 tracks of migratory journeys performed by 84 common terns (Sterna hirundo). Since almost all of these birds are of known sex, age and ancestry and since information on their natal conditions, annual phenology and reproductive performance is available, assessing the causes and consequences of variance in their migratory and navigational phenotype is now within reach.

Team: Sandra Bouwhuis, Nathalie Kürthen

...that doctoral researchers of the highly multidisciplinary Collaborative Research Center SFB 1372 be provided with all necessary scientific and personal skills to pursue their scientific projects and to collaborate effectively. To this end, the iRTG offers a comprehensive qualification and training programme, interdisciplinary education courses, and a stringent management and supervision system for a successful and timely completion of the doctoral project.

Team: Karin Dedek, Heiko Schmaljohann, Tabea Hildebrand

The SFB combines a unique diversity of research areas and methods to clarify the mechanisms behind magnetoreception and navigation in animals. The approach holds a lot of promise but also results in very diverse sets of data. Therefore, data management is a crucial part for the SFB and will be addressed in Inf01 by developing strategies for depositing and sharing the generated data. The aim of Inf01 is to provide an easy-to-use data management system for the researchers that facilitates cooperation within the SFB.

Team: Stefan Harfst, Ilia Solov'yov, Johannes Vosskuhl, Ouria Moridani

Team: Elmar Behrmann (PI), Heide Behrmann (PostDoc)

Team: Dominik Heyers (PI), Katrin Haase (PhD student)

Team: Gabriele Gerlach (PI), Lisa Spiecker (PostDoc)

Team: Arne Nolte (PI), Miriam Liedvogel (PI), Corinna Langebrake (PhD student), Raphael Schween (PhD student)