Chronos Chrimsonr
Chronos Chrimsonr - Related Videos
08:39
Whole-cell Patch-clamp Recordings for Electrophysiological Determination of Ion Selectivity in Channelrhodopsins
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Cited by 26 •
2017
This article describes how the ion selectivity of channelrhodopsin is determined with electrophysiological whole-cell patch-clamp recordings using HEK293 cells. Here, the experimental procedure for investigating chloride selectivity of an anion-selective channelrhodopsin is demonstrated. However, the procedure is transferable to other channelrhodopsins of distinct selectivity.
07:04
Long-range Channelrhodopsin-assisted Circuit Mapping of Inferior Colliculus Neurons with Blue and Red-shifted Channelrhodopsins
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Cited by 4 •
2020
Channelrhodopsin-assisted circuit mapping (CRACM) is a precision technique for functional mapping of long-range neuronal projections between anatomically and/or genetically identified groups of neurons. Here, we describe how to utilize CRACM to map auditory brainstem connections, including the use of a red-shifted opsin, ChrimsonR.
08:31
FM Dye Cycling at the Synapse: Comparing High Potassium Depolarization, Electrical and Channelrhodopsin Stimulation
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Cited by 7 •
2018
Synaptic vesicle (SV) cycling is the core mechanism of intercellular communication at neuronal synapses. FM dye uptake and release are the primary means of quantitatively assaying SV endo- and exocytosis. Here, we compare all the stimulation methods to drive FM1-43 cycling at the Drosophila neuromuscular junction (NMJ) model synapse.
03:01
Drosophila Optogenetics: A Method to Manipulate Neuronal Circuits
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2023
Optogenetics enables the use of light to manipulate neurons that are genetically engineered to express specific opsins–light-sensitive proteins whose light activation triggers a change in the state of the neuron. Here we describe an optogenetic approach in Drosophila using the opsin Channelrhodopsin2. The example protocol features an optogenetics assay set to study the neuronal circuitry behind the fly's escape behavior.
03:05
Photostimulation and Whole-Cell Patch Clamp Recordings of Neurons in Mouse Hippocampal Slices
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2025
The video demonstrates a protocol to study synaptic interactions and neuronal responses in a transfected mouse hippocampal brain slice. It involves illuminating long-range sensory neurons to trigger action potentials and recording the resulting excitatory post-synaptic potentials in the recorded neuron using the whole-cell patch-clamp technique.
FAQs
Their wavelength separation allows investigators to assign blue-light stimulation primarily to Chronos-expressing neurons and red-light stimulation primarily to ChrimsonR-expressing neurons. Because the two opsins occupy different spectral response ranges, illumination can be selected to favor one neuronal population over the other. This reduces dependence on a single optical control channel and enables more precise comparisons within the same circuit.
Rapid channel kinetics determine how closely neuronal activation follows the timing of light delivery. Chronos and ChrimsonR therefore support experiments in which stimulation is linked to defined illumination events, rather than only broad changes in activity. This temporal precision is especially valuable when researchers examine circuit function, because the timing of activation can be related to connectivity or behavioral effects.
When light opens either engineered cation channel, ions move into the membrane-expressing neuron and shift its membrane potential toward depolarization. If the depolarizing effect is sufficient, the neuron becomes activated. This mechanism connects an externally delivered light signal to neuronal activity, giving investigators a direct way to test how selected cells influence downstream circuit function.
Researchers can associate one population with Chronos and the other with ChrimsonR, then use blue or red illumination as separate control channels. The experiment can consequently compare responses produced by activating each population under its corresponding wavelength. This arrangement is useful for dissecting interactions between cell groups without treating the circuit as a single undifferentiated target.
The key elements are opsin expression in the neuronal populations of interest and delivery of the appropriate illumination: blue for Chronos and red for ChrimsonR. Researchers then interpret neuronal, circuit, or behavioral responses in relation to which population was stimulated. Keeping wavelength assignment and target population aligned is essential for meaningful comparisons.
These tools support studies of neural connectivity, circuit function, and behavior. By stimulating distinct expressing populations with spectrally separated light, investigators can ask whether activating one group changes activity or behavior differently from activating another. The approach is therefore suited to complex brain networks where separating contributions from multiple neuronal populations is scientifically important.