FOR 5424:  Modulation of olfaction: how recurrent circuits govern state-dependent behaviour

• Subject Area: Biology ; Medicine
• Term: since 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 466488864

Hunger and reproduction are arguably the two most relevant drives in animal behaviour. Most species – from worms to insects to mammals – heavily rely on olfaction to follow these drives, i.e. to retrieve food and find suitable mating partners. Conversely, metabolic and reproductive states modulate odour perception according to the animal’s behavioural and physiological needs, along with its actual state of general arousal. While we start to understand primary feed-forward processing in olfaction, the role of the many short- and long-range recurrent connections - in part counter to the sensory stream - that are revealed in more and more detail in olfactory systems across phylae remain elusive. Here we propose that these different types of recurrent circuit motifs play an important modulatory role in state-dependent olfactory processing, perception and behaviour. The aim of this initiative is, therefore, to test this hypothesis experimentally in distant animal models (insects versus rodents), from the level of the neuroanatomy of the underlying recurrent circuits, their individual synaptic connectivity and physiology, the modulation of the ensemble activity of principal neurons, to the modulation of perception and behaviour by exemplary fundamental state-dependent variables, i.e. hunger, reproductive drive, arousal, and experience. To achieve this goal, we will jointly develop, standardize and optimize methods, with a special focus on precise control of the olfactory stimulus and on recording techniques suitable for studying recurrent circuit motifs. The expected outcomes of our ambitious research project will be relevant not only for olfactory processing but will reveal essential rules and mechanisms for the function of recurrent connections within the entire nervous system.

• DFG Programme: Research Units
• International Connection: United Kingdom

Projects

• Basal forebrain mediated modulation of information processing in olfactory cortical areas in awake behaving mice (Applicant Rothermel, Markus )
• Coordination Funds (Applicant Egger, Veronica )
• Investigating the role of centrifugal hypothalamic projections to the olfactory system in feeding behaviour (Applicant Steculorum, Ph.D., Sophie )
• Modulation of olfaction by recurrent centrifugal connections after olfactory-visual convergence in the honeybee (Applicants Rössler, Wolfgang ;  Strube-Bloss, Martin Fritz )
• Modulation of recurrent processing within olfactory bulb glomerular columns via granule cells, including their centrifugal glutamatergic inputs from PC and AON (Applicants Egger, Veronica ;  Schaefer, Andreas T. )
• Molecular and cellular mechanisms of oestrus state-dependent odour valence modulation (Applicant Cichy, Annika )
• Optimization and distribution of a precise odour delivery device (Applicants Ackels, Tobias ;  Rothermel, Markus )
• Recurrent connections between higher olfactory brain areas and their role in mating state-dependent behaviour in Drosophila (Applicant Grunwald Kadow, Ilona )
• State-dependent serotonergic long-range modulation of local interneurons in the Drosophila larval antennal lobe (Applicant Vogt, Katrin )
• The role of recurrent long- and short-range connections in experience-dependent modulation in Drosophila (Applicants Knaden, Markus ;  Sachse, Silke )
• TP2 Centrifugal cholinergic modulation of the bulbar vasopressin system (Applicant Egger, Veronica )

• Spokesperson: Professorin Dr. Veronica Egger