A5021217052- Photoreceptor and optogenetics research
- Neuroscience and Neuropharmacology Research
- Neural dynamics and brain function
- Neuroscience and Neural Engineering
- Advanced Fluorescence Microscopy Techniques
- Receptor Mechanisms and Signaling
- Molecular Communication and Nanonetworks
- Retinal Development and Disorders
- Advanced Memory and Neural Computing
- Memory and Neural Mechanisms
- Anesthesia and Neurotoxicity Research
- Pluripotent Stem Cells Research
- Nuclear Structure and Function
- Neurobiology and Insect Physiology Research
- Tissue Engineering and Regenerative Medicine
- Mitochondrial Function and Pathology
- Circadian rhythm and melatonin
- RNA Research and Splicing
- bioluminescence and chemiluminescence research
- Lipid Membrane Structure and Behavior
- Cell Image Analysis Techniques
- Plant Reproductive Biology
- Neurotransmitter Receptor Influence on Behavior
- Genetics, Aging, and Longevity in Model Organisms
- Psychoanalysis and Psychopathology Research
University Medical Center Hamburg-Eppendorf
2014-2024
Universität Hamburg
2014-2024
Heidelberg University
2007-2024
University Hospital Heidelberg
2023-2024
University Medical Centre Mannheim
2023-2024
Institute of Neurobiology and Molecular Medicine
2023
Friedrich Miescher Institute
2009-2011
University of California, San Francisco
2010
Center for Neurosciences
2009
The field of optogenetics uses channelrhodopsins (ChRs) for light-induced neuronal activation. However, optimized tools cellular inhibition at moderate light levels are lacking. We found that replacement E90 in the central gate ChR with positively charged residues produces chloride-conducting ChRs (ChloCs) only negligible cation conductance. Molecular dynamics modeling unveiled a high-affinity Cl(-)-binding site had been generated near gate. Stabilizing open state dramatically increased...
Abstract Optogenetic manipulation of neuronal activity through excitatory and inhibitory opsins has become an indispensable experimental strategy in neuroscience research. For many applications bidirectional control allowing both excitation inhibition the same neurons a single experiment is desired. This requires low spectral overlap between opsin, matched photocurrent amplitudes fixed expression ratio. Moreover, independent activation two distinct populations with different optogenetic...
Abstract Responses of the insular cortex (IC) and amygdala to stimuli positive negative valence are altered in patients with anxiety disorders. However, neural coding both by IC neurons remains unknown. Using fiber photometry recordings mice, we uncover a selective increase activity projection anterior (aIC), but not posterior (pIC) section, when animals exploring anxiogenic spaces, this is proportional level mice. Neurons aIC also respond valence, strength response strong mice levels...
Channelrhodopsins are light-activated ion channels that mediate cation permeation across cell membranes upon light absorption. Red-light-activated channelrhodopsins of particular interest, because red penetrates deeper into biological tissues and also enables dual-color experiments in combination with blue-light-activated optogenetic tools. Here we report the crystal structure most red-shifted channelrhodopsin from algae Chlamydomonas noctigama, Chrimson, at 2.6 Å resolution. Chrimson...
Significance Excitatory synapses convert presynaptic action potentials into chemical signals that are sensed by postsynaptic glutamate receptors. To eavesdrop on synaptic transmission, genetically encoded fluorescent sensors for have been developed. However, even the best available lag behind very fast dynamics in cleft. Here, we report development of an ultrafast sensor, iGlu u , which allowed us to image clearance and depression during 100-Hz spike trains. We found only boutons showing...
Long-term depression (LTD) weakens synaptic transmission in an activity-dependent manner. It is not clear, however, whether individual synapses are able to maintain a depressed state indefinitely, as intracellular recordings rarely exceed 1 h. Here, we combine optogenetic stimulation of identified Schaffer collateral axons with two-photon imaging postsynaptic calcium signals and follow the fate for 7 d after LTD induction. Optogenetic CA3 pyramidal cells at Hz led strong reliable transients...
Channelrhodopsins are light-gated cation channels that have been widely used for optogenetic stimulation of electrically excitable cells. Replacement a glutamic acid in the central gate with positively charged amino residue reverses ion selectivity and produces chloride-conducting ChRs (ChloCs). Expressed neurons, published ChloCs produced strong shunting effect but also small, yet significant depolarization from resting potential. Depending on state neuron, net result illumination might...
Abstract Coordinated activity patterns in the developing brain may contribute to wiring of neuronal circuits underlying future behavioural requirements. However, causal evidence for this hypothesis has been difficult obtain owing absence tools selective manipulation oscillations during early development. We established a protocol that combines optogenetics with electrophysiological recordings from neonatal mice vivo elucidate substrate network prefrontal cortex. show light-induced activation...
Abstract Information is transmitted between brain regions through the release of neurotransmitters from long-range projecting axons. Understanding how activity such connections contributes to behavior requires efficient methods for reversibly manipulating their function. Chemogenetic and optogenetic tools, acting endogenous G-protein-coupled receptor pathways, can be used modulate synaptic transmission, but existing tools are limited in sensitivity, spatiotemporal precision or spectral...
Synaptic activity initiates many adaptive responses in neurons. Here we report a novel form of structural plasticity dissociated hippocampal cultures and slice preparations. Using recently developed algorithm for three-dimensional image reconstruction quantitative measurements cell organelles, found that nuclei from neurons are highly infolded unequally sized nuclear compartments. Nuclear infoldings dynamic structures, which can radically transform the geometry nucleus response to neuronal...
This protocol describes the preparation of hippocampal slice cultures from rat or mouse pups using sterile conditions that do not require use antibiotics antimycotics. Combining very good optical and electrophysiological accessibility with a lifetime approaching intact animal, many fundamental questions about synaptic plasticity long-term dynamics network connectivity can be addressed this preparation.
Organization of signalling molecules in biological membranes is crucial for cellular communication. Many receptors, ion channels and cell adhesion are associated with proteins important their trafficking, surface localization or function. These complexes embedded a lipid environment varying composition. Binding affinities stoichiometry such were so far experimentally accessible only isolated systems monolayers culture. Visualization molecular dynamics within correlation to specialized...
Channelrhodopsins (ChRs) are algal light-gated ion channels widely used as optogenetic tools for manipulating neuronal activity. ChRs desensitize under continuous bright-light illumination, resulting in a significant decline of photocurrents. Here we describe metagenomically identified family phylogenetically distinct anion-conducting (designated MerMAIDs). MerMAIDs almost completely during illumination due to accumulation late non-conducting photointermediate that disrupts the permeation...
Single-cell electroporation allows the transfection of a small number neurons in an organotypic culture with single plasmid or defined mixture plasmids. Desired protein expression levels can vary depending on experimental goals (e.g., high are needed for optogenetic experiments); however, when too much is expressed, cellular toxicity and cell death may arise. To large degree, be controlled by adjusting concentration DNA pipette. Here, we present protocol transfecting individual hippocampal...
Abstract Information within the brain travels from neuron to across billions of synapses. At any given moment, only a small subset neurons and synapses are active, but finding active in tissue has been technical challenge. Here we introduce SynTagMA tag user-defined time window. Upon 395–405 nm illumination, this genetically encoded marker activity converts green red fluorescence if, it is bound calcium. Targeted presynaptic terminals, preSynTagMA allows discrimination between silent axons....
General anesthesia is characterized by reversible loss of consciousness accompanied transient amnesia. Yet, long-term memory impairment an undesirable side effect. How different types general anesthetics (GAs) affect the hippocampus, a brain region central to formation and consolidation, poorly understood. Using extracellular recordings, chronic 2-photon imaging, behavioral analysis, we monitor effects isoflurane (Iso), medetomidine/midazolam/fentanyl (MMF), ketamine/xylazine (Keta/Xyl) on...
We developed a family of genetically encoded serotonin (5-HT) sensors (sDarken) on the basis native 5-HT1A receptor and circularly permuted GFP. sDarken 5-HT are bright in unbound state diminish their fluorescence upon binding 5-HT. Sensor variants with different affinities for were engineered to increase versatility imaging dynamics. Experiments vitro vivo showed feasibility dynamics high temporal spatial resolution. As demonstrated here, designed show excellent membrane expression, have...
Abstract G q proteins are universally important for signal transduction in mammalian cells. The underlying kinetics and transformation from extracellular stimuli into intracellular signaling, however could not be investigated detail so far. Here we present the human Neuropsin (hOPN5) specific repetitive manipulation of signaling vitro vivo with high spatio-temporal resolution. Properties protein specificity hOPN5 characterized by UV light induced IP 3 generation, Ca 2+ transients inhibition...
Abstract Information processing in the brain is controlled by quantal release of neurotransmitters, a tightly regulated process. From ultrastructural analysis, it known that presynaptic boutons along single axons differ number vesicles docked at active zone. It not clear whether probability these to get released ( p ves ) homogenous or also varies between individual boutons. Here, we optically measure evoked transmitter Schaffer collateral synapses different calcium concentrations, using...