Mit einer öffentlichen Vortragsreihe präsentieren und diskutieren wir allgemeinverständlich interdisziplinäre Ansätze in der Hirnforschung. In einem Wechsel aus internationalen, nationalen und lokalen Beiträgen stellen wir ein buntes Spektrum an Forschungshighlights aus Bremen und "umzu" vor.
Erfahren Sie vor Ort, wie die wissenschaftliche Zusammenarbeit zwischen verschiedenen Disziplinen zu einem vertiefenden Verständnis der Funktion des Gehirns beiträgt. Nehmen Sie am wissenschaftlichen Gedankenaustausch der beteiligten Institute teil, und sprechen Sie persönlich mit den Forschern, die am Gehirn und "umzu" interessiert sind!
Wir freuen uns auf Ihre/Eure Teilnahme!
13.05.2024 | 17:00 - 18:30
Raum 2030, Cognium, Hochschulring 18
A new optrode device for optogenetic stimulation of deep cortical layers based on the Utah array geometry
Dr. Christopher Friedrich Reiche
Optogenetic methods enable neuroscientist to study neural circuit function with high precision by making specifically targeted populations of neural tissue cells sensitive to light. To harness the full capabilities of this technique, it is essential for researchers to be able to deliver light with sufficient intensity not only to the surface but also into deep layers of the brain. In addition to this, a high level of spatial and temporal control is required while, at the same time, preventing stimulation artifacts or damage to the tissue by excessive heat generation. To address this challenge, we developed a novel neural implant device for light delivery based on the Utah Electrode Array (UEA) geometry: the Utah Optrode Array (UOA). This novel device combines a matrix-addressed µLED chip for light generation with an optical interposer and an array of needle-shaped borosilicate glass waveguides. Both the fabrication process of the waveguide array as well as encapsulation and wiring strategies are based on those used for the established UEA. In this talk the details on the development of the UOA along with its fabrication process and characterization, as well as the first successful in vivo experiments will be discussed.
27.05.2024 | 17:00 - 18:30
Raum 2030, Cognium, Hochschulring 18
Optical approaches to study glutamate receptor signaling: Mechanisms and synaptic function
Prof. Dr. Andreas Reiner
Glutamate receptors (GluRs) play a key role in the central nervous system, where they pass excitatory signals across synapses and modulate synaptic strength and plasticity. Our research mainly focuses on the subfamily of ionotropic glutamate receptors (iGluRs), which form glutamate-gated ion channels. In my talk, I will summarize our recent work on the diversity of this receptor family and discuss, how different receptor subunits may contribute to gating of the ion channel pore, which is an aspect that also has pharmacological implications. For these studies we heavily rely on optical methods: A particularly useful part of our toolset are chemical photoswitches (tethered photoswitchable ligands) that allow for the precise optical control of specific receptor subunits with high spatial and temporal precision. Besides this, we use genetically encoded sensors to investigate glutamatergic signaling in the context of pathological conditions, e.g. ischemic stress conditions.
03.06.2024 | 16:00 - 17:30
Haus der Wissenschaft, Sandstraße 4/5, Olbers-Saal
Die tiefe Hirnstimulation: State of the Art und Entwicklungen
Prof. Dr. Joachim Krauss
Die Tiefe Hirnstimulation ist mittlerweile ein etabliertes therapeutisches Verfahren, welches einen festen Platz gefunden hat bei der Behandlung von Bewegungsstörungen wie der Parkinson Erkrankung, dem essentiellen Tremor und verschiedenen Formen der Dystonie. Ferner wird die Methode angewendet bei psychiatrischen Erkrankungen wie der Zwangsstörung, neuropathischen Schmerzsyndromen und bestimmten Epilepsie-Formen. Weitere Indikationen sind Gegenstand der intensiven Forschung. In den letzten Jahren kam es zu wesentlichen Fortschritten in der Schrittmacher-Technologie und zu weiteren technischen Entwicklungen. Von besonderem zukünftigem Interesse ist die Einführung von closed-loop Methoden unter Verwendung von künstlicher Intelligenz. Erste Schritte sind hier sehr vielversprechend.
10.06.2024 | 17:00 - 18:30
Raum 2030, Cognium, Hochschulring 18
Plastic electronic brain interfaces: organic semiconductors for optogenetics and fluorescence imaging
Dr. Caroline Murawski
Neurological disorders are becoming increasingly common in our aging society. In order to improve our understanding of the brain and find therapy and treatment, methods are required to precisely control and monitor neuronal signals. Optogenetics and fluorescence imaging use light for stimulation and recording, respectively. This enables unprecedented spatial and temporal control over neuronal activity and read-out from thousands of cells simultaneously. The use of optics for interrogation and monitoring requires light sources and sensors that can be integrated with soft tissue and operated in direct contact with cells. In my talk, I will present how organic semiconductor devices, which are based on plastic-type materials that are fabricated on micrometre-thin, flexible substrates, may be used as brain interfaces. Multi-coloured organic LEDs are used in vitro and for activation and inhibition of neuronal activity in Drosophila melanogaster (fruit flies). Furthermore, the development of flexible sensors for fluorescence imaging is discussed and first results using organic LEDs and photodiodes will be presented.
17.06.2024 | 17:00 - 18:30
Raum 2030, Cognium, Hochschulring 18
"Clickety-clack": a non-equilibrium model of cortical activity performs perceptual inference
Prof. Dr. Jochen Braun
How does the cortex of humans and primates interpret unstable and ambiguous sensory input in terms of lifelong prior experience? Current theories ("free energy principle", "predictive coding") are based on equilibrium physics and posit reciprocal interactions between cortical levels ("top-down" and "bottom-up") to compare sensory input with prior experience and minimise discrepancies.
I propose a novel hypothesis -- an non-equilibrium hierarchy of birth-death processes -- formulated as a mesoscopic model of cortical activity at level of columns. The model relies on standard cortical artchitecture and connectivity (feedforward projections shape tuning, recurring connections normalize gain) and is based on the dynamics of multi-stable perception, which strongly implicates a far-from-equilibrium birth-death process.
The model links all levels of analysis of Marr: computation (optimal inference), algorithm (birth-death hierarchy) and implementation (attractor dynamics of cortical columns). I conclude that that perceptual inference may rely on a variational principle of non-equilibrium ("maximum caliber") and that stochastic neural activity ("noise correlations" or "shared variability") may be beneficial -- not detrimental -- for physiological function.
01.07.2024 | 17:00 - 18:30
Raum 2030, Cognium, Hochschulring 18
Unravelling brain Networks: How correlations between brain regions can help us understand brain (dys)function
Dr. Jana Schill
Brain function relies on a complex interplay of different brain regions. This interplay is known to change during healthy aging, and it can be disrupted in neurological diseases such as dystonia and Parkinson’s disease. In my talk I will present how viewing brain regions as nodes of a graph allows us to employ methods from the mathematical field of graph theory to better understand brain function. I will highlight that by investigating communication across the whole-brain network, it is possible to gain insight into how the brain functions, how neurological conditions and age affect the brain, and how the brain can ensure function through compensatory mechanisms in network communication.
Die Vorträge werden größtenteils auf Englisch gehalten (siehe Titel).
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