International centre for translational eye research 

Molecular Modulators of Photoreceptor Dynamics: From Structure to Functional Biomarkers in the Living Retina

Photoreceptors are active biological sensors, and proteins involved in the visual cycle and phototransduction cascade, such as RBP3 and PDE6, undergo dynamic conformational changes tightly coupled to vision. In this talk, I will present an integrative structural biology program that combines cryoEM, cryoET, SAXS, and advanced imaging (including flicker optoretinography (f-ORG) and two-photon excitation fluorescence (TPEF)) to reveal how retinal proteins transform light into mechanical and chemical signals. Using f-ORG, we resolve nanometer-scale outer segment elongations and are now testing if PDE6 drives the conformational shifts during the light stimulus. In parallel, we resolved porcine RBP3 at 3.67 Å, characterized its ligand-driven flexibility, and will explore its potential as an early diagnostic biomarker in diabetic retinopathy, using TPEF. These molecules, traditionally viewed as intermediates, are emerging as functional indicators, therapeutic targets, and possible molecular transducers in broader light-dependent sensory processes.

Host: Karl Koch

Excursion to Wilhelmshaven + Picnic

Host: Nathalie Kürten

iRTG seminar summer break

(except for guest talks inbetween)

Reinhard Lab at Scuola Internazionale Superiore di Studi Avanzati (SISSA), Italy

The Neural Underpinning of Flexibility in Survival Behaviours

Avoiding danger is one of the most essential and conserved set of behaviours, observed in most species from crabs to primates. To optimize an animal’s survival, avoidance responses need to be fast and reliable, but also flexible and adaptable to the current context. However, how this flexibility in behavioural output is implemented in the brain is largely unknown. Furthermore, it is unclear how similar the precise circuits and mechanisms underlying a conserved behaviour are across contexts and species. The goal of my lab is to identify how information about the environment and state can adapt behavioural decision making. We approach this by using a highly standardized assay where we compare innate reactions and neural circuit activity while changing selected contextual elements. During this seminar, I will first introduce the ‘hard-wired’ neural circuit architecture from the retina to pre-motor areas that underlies survival behaviours, and discuss how this architecture allows for contextual information to shape those behaviours. Then I will focus on two specific examples of flexibility and their underlying neural circuits: (1) how ambient light changes and circadian rhythm temporarily adapt innate behaviours and (2) how habitat differences have led to the evolution of permanent changes in survival behaviour in different rodent species.

Host: Rabea Bartölke

Calegari Lab

Center for Regenerative Therapies Dresden

Technical University Dresden

https://www.shonalidhingra.com/

Interaction of sensory modalities and adult neurogenesis in rodent navigation

Hippocampus is considered as the brain’s processor for spatial navigation in mammals. Hippocampal place cells form the bases for this processing, and in making a cognitive map of space to guide navigation. The tuning of these place cells has shown to be closely tied to the visual cues around the animal. My recent rodent work showed that the location specificity of these place cells was highly correlated with the amount of visual information around the animal. Additionally, these place cells completely lost their spatial tuning when the animals were unable to coordinate the visual information with their own self-motion cues or proprioception. Using these findings, I hypothesize that the interaction and co-localization of information from different sensory modalities might be required for formation of place cells and precise navigation in rodents. Further, I am also currently investigating the potential role of hippocampal adult neurogenesis in gating sensory information from reaching these place cells, as animals with higher adult neurogenesis were found to navigate better. 

Host: Henrik Mouritsen

Guest talk by Valeria Marasco

(Research Institute of Wildlife Ecology, University of Veterinary Medicine Vienna)

https://valeriamarasco.blog/about/

Host: Miriam Liedvogel

Max Planck research group leader in Seewiesen

Host: Miriam

Location: BIS hall at the UOL Campus Haarentor