Search results for "optogenetics"

Optical activation of TrkB neurotrophin receptor in mouse ventral hippocampus promotes plasticity and facilitates fear extinction

2021

AbstractSuccessful extinction of traumatic memories depends on neuronal plasticity in the fear extinction network. However, the mechanisms involved in the extinction process remain poorly understood. Here, we investigated the fear extinction network by using a new optogenetic technique that allows temporal and spatial control of neuronal plasticity in vivo. We optimized an optically inducible TrkB (CKII-optoTrkB), the receptor of the brain-derived neurotrophic factor, which can be activated upon blue light exposure to increase plasticity specifically in pyramidal neurons. The activation of CKII-optoTrkB facilitated the induction of LTP in Schaffer collateral-CA1 synapses after brief theta-b…

Cortical Recruitment Determines Learning Dynamics and Strategy

2018

AbstractSalience is a broad and widely used concept in neuroscience whose neuronal correlates, however, remain elusive. In behavioral conditioning, salience is used to explain various effects, such as stimulus overshadowing, and refers to how fast and strongly a stimulus can be associated with a conditioned event. Here, we show that sounds of diverse quality, but equal intensity and perceptual detectability, can recruit different levels of population activity in mouse auditory cortex. When using these sounds as cues in a Go/NoGo discrimination task, the degree of cortical recruitment matches the salience parameter of a reinforcement learning model used to analyze learning speed. We test an …

OPETH: Open Source Solution for Real-Time Peri-Event Time Histogram Based on Open Ephys

2019

Single cell electrophysiology remains one of the most widely used approaches of systems neuroscience. Decisions made by the experimenter during electrophysiology recording largely determine recording quality, duration of the project and value of the collected data. Therefore, online feedback aiding these decisions can lower monetary and time investment, and substantially speed up projects as well as allow novel studies otherwise not possible due to prohibitively low throughput. Real-time feedback is especially important in studies that involve optogenetic cell type identification by enabling a systematic search for neurons of interest. However, such tools are scarce and limited to costly co…

In vivo Imaging of Fully Active Brain Tissue in Awake Zebrafish Larvae and Juveniles by Skull and Skin Removal.

2021

Understanding the ephemeral changes that occur during brain development and maturation requires detailed high-resolution imaging in space and time at cellular and subcellular resolution. Advances in molecular and imaging technologies have allowed us to gain numerous detailed insights into cellular and molecular mechanisms of brain development in the transparent zebrafish embryo. Recently, processes of refinement of neuronal connectivity that occur at later larval stages several weeks after fertilization, which are for example control of social behavior, decision making or motivation-driven behavior, have moved into focus of research. At these stages, pigmentation of the zebrafish skin inter…

Making Waves: Initiation and Propagation of Corticothalamic Ca2+ Waves In Vivo

2013

Corticothalamic slow oscillations of neuronal activity determine internal brain states. At least in the cortex, the electrical activity is associated with large neuronal Ca(2+) transients. Here we implemented an optogenetic approach to explore causal features of the generation of slow oscillation-associated Ca(2+) waves in the in vivo mouse brain. We demonstrate that brief optogenetic stimulation (3-20 ms) of a local group of layer 5 cortical neurons is sufficient for the induction of global brain Ca(2+) waves. These Ca(2+) waves are evoked in an all-or-none manner, exhibit refractoriness during repetitive stimulation, and propagate over long distances. By local optogenetic stimulation, we …

Optogenetic Control of Intracellular Signaling: Class II Opsins

2017

Optogenetic Control of Bacterial Expression by Red Light

2022

In optogenetics, as in nature, sensory photoreceptors serve to control cellular processes by light. Bacteriophytochrome (BphP) photoreceptors sense red and far-red light via a biliverdin chromophore and, in response, cycle between the spectroscopically, structurally, and functionally distinct Pr and Pfr states. BphPs commonly belong to two-component systems that control the phosphorylation of cognate response regulators and downstream gene expression through histidine kinase modules. We recently demonstrated that the paradigm BphP from Deinococcus radiodurans exclusively acts as a phosphatase but that its photosensory module can control the histidine kinase activity of homologous receptors.…

Optogenetically blocking sharp wave ripple events in sleep does not interfere with the formation of stable spatial representation in the CA1 area of …

2016

During hippocampal sharp wave/ripple (SWR) events, previously occurring, sensory inputdriven neuronal firing patterns are replayed. Such replay is thought to be important for plasticity-related processes and consolidation of memory traces. It has previously been shown that the electrical stimulation-induced disruption of SWR events interferes with learning in rodents in different experimental paradigms. On the other hand, the cognitive map theory posits that the plastic changes of the firing of hippocampal place cells constitute the electrophysiological counterpart of the spatial learning, observable at the behavioral level. Therefore, we tested whether intact SWR events occurring during th…

Neuronal activity triggers uptake of hematopoietic extracellular vesicles in vivo

2019

Communication with the hematopoietic system is a vital component of regulating brain function in health and disease. Traditionally, the major routes considered for this neuroimmune communication are by individual molecules such as cytokines carried by blood, by neural transmission, or, in more severe pathologies, by the entry of peripheral immune cells into the brain. In addition, functional mRNA from peripheral blood can be directly transferred to neurons via extracellular vesicles (EVs), but the parameters that determine their uptake are unknown. Using varied animal models that stimulate neuronal activity by peripheral inflammation, optogenetics, and selective proteasome inhibition of dop…

Temporally precise control of single-neuron spiking by juxtacellular nanostimulation

2017

Temporal patterns of action potentials influence a variety of activity-dependent intra- and intercellular processes and play an important role in theories of neural coding. Elucidating the mechanisms underlying these phenomena requires imposing spike trains with precisely defined patterns, but this has been challenging due to the limitations of existing stimulation techniques. Here we present a new nanostimulation method providing control over the action potential output of individual cortical neurons. Spikes are elicited through the juxtacellular application of short-duration fluctuating currents (“kurzpulses”), allowing for the sub-millisecond precise and reproducible induction of arbitr…