Perceptions and decisions depend on sensory impressions, but also on past experiences and the internal state of an animal. Behavior is therefore very adaptive and flexible. Which signals and neural networks allow the communication between brain and body? And how do they modulate behavior? In this project, we studied these questions on the example of the senses of smell and taste, the most important modalities in food-related decisions and preferences. Specifically, we wanted to understand how chemosensory information is processed by the brain to guide decision-making and how physiology and metabolic needs such as hunger influence neuronal processes and cognitive function. To this end, we were using an interdisciplinary approach combining molecular biology, genetics, electrophysiology, in vivo multiphoton functional imaging and state-of-the-art behavioral analysis in the animal model Drosophila melanogaster.
The project was divided into three main workpackages (WP). The goal of WP1 was to identify the neural circuit mechanisms underpinning hunger state-dependent changes in chemosensory preference and choice behavior. In several publications, we showed that the mushroom body, the learning center of the fly, played a crucial role in foraging behavior and decision-making in hungry animals. In particular, we showed that dopaminergic neurons carry information regarding the valence of odors in a hunger state-dependent manner and thereby influence goal-directed behavior. In WP2, we concentrated on the role of reproductive state in chemosensory choices of female flies. We published several papers showing that mating modulates taste and odor processing at multiple stages in chemosensory processing -from sensory neurons to the two higher olfactory brain centers of insects. Moreover, we found that dopaminergic neurons played an important role in conveying mating state to these higher brain centers and thereby strongly impacted on chemosensory choices. Finally, in WP3, we explored the impact of pathogen infection on chemosensory processing and behavior. In a recent publication, we showed that flies lastingly adapt their feeding behavior using their mushroom body when exposed to food contaminated with pathogenic bacteria. Our data suggested that ingested pathogens activate the innate immune system which then communicates the presence of pathogens through specific neural circuits to ultimately adapt feeding behavior.
Overview of results and their dissemination:
1. Selected publications:
• Kobler J, Rodriguez FJ, Petcu I, Grunwald Kadow IC (2020). Current Biology 28:S0960-9822(20)31353-1
• K.P. Siju, Stih V, Aimon S, Gjorgjieva J, Portugues P, Grunwald Kadow IC (2020). Current Biology 30(11):2104-2115.
• Sayin S, De Backer JF, Wosniack ME, Lewis L, Siju KP, Frisch LM, Schlegel P, Edmondson-Stait A, Sharifi N, Fisher CB, Calle-Schuler S, Lauritzen S, Bock D, Costa M, Jefferis GSXE, Gjorgjieva J, Grunwald Kadow IC (2019). Neuron 104, 544–558
• Hussain, A, Pooryasin, A, Zhang, M, Loschek, LF, La Fortezza, M, Friedrich, AB, Blais, CM, Üçpunar, HK, Yépez, YA, Lehmann, M, Gompel, N, Gagneur, J, Sigrist, SJ and Grunwald Kadow IC (2018). eLife 2018;7:e32018.
• Hussain A*, Zhang M*, Üçpunar HK, Svensson T, Quillery E, Gompel N, Ignell R, Grunwald Kadow IC (2016). PLoS Biology 14:e1002454. doi:10.1371
• Hussain A*, Üçpunar HK*, Zhang M, Loschek LF, Grunwald Kadow IC (2016). PLoS Biology 14:e1002455. doi: 10.1371
2. Science outreach:
• Initiator and co-organizer of the public seminar series ‘TUM@Freising – Wissenschaft erklärt für alle’
• Speaker at TEDxTUM conference 2018 ‘Conscious Reflection’, Munich, Germany
• Speaker and discussion panelist at ‘Women of TUM’ talks 2020 on the topic ‘Mot:vat:on’
• Contributed expertise and interviews to public Science shows and journals (Radio Mikro – Bayern 2, dasGehirn.info Revista SAÚDE, 3Sat nano aha, Quarks&Co, latestThinking.org Bild der Wissenschaft)
3. Scientific presentations (selected):
Plenary lecture at Neurofly 2020, Toledo, Spain
Keynote speaker at ECRO (European Chemoreception Research Organization) Conference 2020 (Dresden, Germany)
Invited seminar at King’s college, London, UK, 2019
Invited seminar at Salk Institute, San Diego, USA, 2018
‘Structure and Function of the Insect Mushroom Body’ Conference, Janelia Research Campus, Ashburn, U.S.A. 2017